Add a comprehensive framework for formally documenting kernel APIs with
inline specifications. This framework provides:
- Structured API documentation with parameter specifications, return
values, error conditions, and execution context requirements
- Runtime validation capabilities for debugging (CONFIG_KAPI_RUNTIME_CHECKS)
- Export of specifications via debugfs for tooling integration
- Support for both internal kernel APIs and system calls
The framework stores specifications in a dedicated ELF section and
provides infrastructure for:
- Compile-time validation of specifications
- Runtime querying of API documentation
- Machine-readable export formats
- Integration with existing SYSCALL_DEFINE macros
This commit introduces the core infrastructure without modifying any
existing APIs. Subsequent patches will add specifications to individual
subsystems.
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
Documentation/admin-guide/kernel-api-spec.rst | 507 ++++++
MAINTAINERS | 9 +
arch/um/kernel/dyn.lds.S | 3 +
arch/um/kernel/uml.lds.S | 3 +
arch/x86/kernel/vmlinux.lds.S | 3 +
include/asm-generic/vmlinux.lds.h | 20 +
include/linux/kernel_api_spec.h | 1513 +++++++++++++++++
include/linux/syscall_api_spec.h | 137 ++
include/linux/syscalls.h | 38 +
init/Kconfig | 2 +
kernel/Makefile | 1 +
kernel/api/Kconfig | 35 +
kernel/api/Makefile | 7 +
kernel/api/kernel_api_spec.c | 1122 ++++++++++++
14 files changed, 3400 insertions(+)
create mode 100644 Documentation/admin-guide/kernel-api-spec.rst
create mode 100644 include/linux/kernel_api_spec.h
create mode 100644 include/linux/syscall_api_spec.h
create mode 100644 kernel/api/Kconfig
create mode 100644 kernel/api/Makefile
create mode 100644 kernel/api/kernel_api_spec.c
diff --git a/Documentation/admin-guide/kernel-api-spec.rst b/Documentation/admin-guide/kernel-api-spec.rst
new file mode 100644
index 0000000000000..3a63f6711e27b
--- /dev/null
+++ b/Documentation/admin-guide/kernel-api-spec.rst
@@ -0,0 +1,507 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================================
+Kernel API Specification Framework
+======================================
+
+:Author: Sasha Levin <sashal@kernel.org>
+:Date: June 2025
+
+.. contents:: Table of Contents
+ :depth: 3
+ :local:
+
+Introduction
+============
+
+The Kernel API Specification Framework (KAPI) provides a comprehensive system for
+formally documenting, validating, and introspecting kernel APIs. This framework
+addresses the long-standing challenge of maintaining accurate, machine-readable
+documentation for the thousands of internal kernel APIs and system calls.
+
+Purpose and Goals
+-----------------
+
+The framework aims to:
+
+1. **Improve API Documentation**: Provide structured, inline documentation that
+ lives alongside the code and is maintained as part of the development process.
+
+2. **Enable Runtime Validation**: Optionally validate API usage at runtime to catch
+ common programming errors during development and testing.
+
+3. **Support Tooling**: Export API specifications in machine-readable formats for
+ use by static analyzers, documentation generators, and development tools.
+
+4. **Enhance Debugging**: Provide detailed API information at runtime through debugfs
+ for debugging and introspection.
+
+5. **Formalize Contracts**: Explicitly document API contracts including parameter
+ constraints, execution contexts, locking requirements, and side effects.
+
+Architecture Overview
+=====================
+
+Components
+----------
+
+The framework consists of several key components:
+
+1. **Core Framework** (``kernel/api/kernel_api_spec.c``)
+
+ - API specification registration and storage
+ - Runtime validation engine
+ - Specification lookup and querying
+
+2. **DebugFS Interface** (``kernel/api/kapi_debugfs.c``)
+
+ - Runtime introspection via ``/sys/kernel/debug/kapi/``
+ - JSON and XML export formats
+ - Per-API detailed information
+
+3. **IOCTL Support** (``kernel/api/ioctl_validation.c``)
+
+ - Extended framework for IOCTL specifications
+ - Automatic validation wrappers
+ - Structure field validation
+
+4. **Specification Macros** (``include/linux/kernel_api_spec.h``)
+
+ - Declarative macros for API documentation
+ - Type-safe parameter specifications
+ - Context and constraint definitions
+
+Data Model
+----------
+
+The framework uses a hierarchical data model::
+
+ kernel_api_spec
+ ├── Basic Information
+ │ ├── name (API function name)
+ │ ├── version (specification version)
+ │ ├── description (human-readable description)
+ │ └── kernel_version (when API was introduced)
+ │
+ ├── Parameters (up to 16)
+ │ └── kapi_param_spec
+ │ ├── name
+ │ ├── type (int, pointer, string, etc.)
+ │ ├── direction (in, out, inout)
+ │ ├── constraints (range, mask, enum values)
+ │ └── validation rules
+ │
+ ├── Return Value
+ │ └── kapi_return_spec
+ │ ├── type
+ │ ├── success conditions
+ │ └── validation rules
+ │
+ ├── Error Conditions (up to 32)
+ │ └── kapi_error_spec
+ │ ├── error code
+ │ ├── condition description
+ │ └── recovery advice
+ │
+ ├── Execution Context
+ │ ├── allowed contexts (process, interrupt, etc.)
+ │ ├── locking requirements
+ │ └── preemption/interrupt state
+ │
+ └── Side Effects
+ ├── memory allocation
+ ├── state changes
+ └── signal handling
+
+Usage Guide
+===========
+
+Basic API Specification
+-----------------------
+
+To document a kernel API, use the specification macros in the implementation file:
+
+.. code-block:: c
+
+ #include <linux/kernel_api_spec.h>
+
+ KAPI_DEFINE_SPEC(kmalloc_spec, kmalloc, "3.0")
+ KAPI_DESCRIPTION("Allocate kernel memory")
+ KAPI_PARAM(0, size, KAPI_TYPE_SIZE_T, KAPI_DIR_IN,
+ "Number of bytes to allocate")
+ KAPI_PARAM_RANGE(0, 0, KMALLOC_MAX_SIZE)
+ KAPI_PARAM(1, flags, KAPI_TYPE_FLAGS, KAPI_DIR_IN,
+ "Allocation flags (GFP_*)")
+ KAPI_PARAM_MASK(1, __GFP_BITS_MASK)
+ KAPI_RETURN(KAPI_TYPE_POINTER, "Pointer to allocated memory or NULL")
+ KAPI_ERROR(ENOMEM, "Out of memory")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SOFTIRQ | KAPI_CTX_HARDIRQ)
+ KAPI_SIDE_EFFECT("Allocates memory from kernel heap")
+ KAPI_LOCK_NOT_REQUIRED("Any lock")
+ KAPI_END_SPEC
+
+ void *kmalloc(size_t size, gfp_t flags)
+ {
+ /* Implementation */
+ }
+
+System Call Specification
+-------------------------
+
+System calls use specialized macros:
+
+.. code-block:: c
+
+ KAPI_DEFINE_SYSCALL_SPEC(open_spec, open, "1.0")
+ KAPI_DESCRIPTION("Open a file")
+ KAPI_PARAM(0, pathname, KAPI_TYPE_USER_STRING, KAPI_DIR_IN,
+ "Path to file")
+ KAPI_PARAM_PATH(0, PATH_MAX)
+ KAPI_PARAM(1, flags, KAPI_TYPE_FLAGS, KAPI_DIR_IN,
+ "Open flags (O_*)")
+ KAPI_PARAM(2, mode, KAPI_TYPE_MODE_T, KAPI_DIR_IN,
+ "File permissions (if creating)")
+ KAPI_RETURN(KAPI_TYPE_INT, "File descriptor or -1")
+ KAPI_ERROR(EACCES, "Permission denied")
+ KAPI_ERROR(ENOENT, "File does not exist")
+ KAPI_ERROR(EMFILE, "Too many open files")
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+ KAPI_SIGNAL(EINTR, "Open can be interrupted by signal")
+ KAPI_END_SYSCALL_SPEC
+
+IOCTL Specification
+-------------------
+
+IOCTLs have extended support for structure validation:
+
+.. code-block:: c
+
+ KAPI_DEFINE_IOCTL_SPEC(vidioc_querycap_spec, VIDIOC_QUERYCAP,
+ "VIDIOC_QUERYCAP",
+ sizeof(struct v4l2_capability),
+ sizeof(struct v4l2_capability),
+ "video_fops")
+ KAPI_DESCRIPTION("Query device capabilities")
+ KAPI_IOCTL_FIELD(driver, KAPI_TYPE_CHAR_ARRAY, KAPI_DIR_OUT,
+ "Driver name", 16)
+ KAPI_IOCTL_FIELD(card, KAPI_TYPE_CHAR_ARRAY, KAPI_DIR_OUT,
+ "Device name", 32)
+ KAPI_IOCTL_FIELD(version, KAPI_TYPE_U32, KAPI_DIR_OUT,
+ "Driver version")
+ KAPI_IOCTL_FIELD(capabilities, KAPI_TYPE_FLAGS, KAPI_DIR_OUT,
+ "Device capabilities")
+ KAPI_END_IOCTL_SPEC
+
+Runtime Validation
+==================
+
+Enabling Validation
+-------------------
+
+Runtime validation is controlled by kernel configuration:
+
+1. Enable ``CONFIG_KAPI_SPEC`` to build the framework
+2. Enable ``CONFIG_KAPI_RUNTIME_CHECKS`` for runtime validation
+3. Optionally enable ``CONFIG_KAPI_SPEC_DEBUGFS`` for debugfs interface
+
+Validation Modes
+----------------
+
+The framework supports several validation modes:
+
+.. code-block:: c
+
+ /* Enable validation for specific API */
+ kapi_enable_validation("kmalloc");
+
+ /* Enable validation for all APIs */
+ kapi_enable_all_validation();
+
+ /* Set validation level */
+ kapi_set_validation_level(KAPI_VALIDATE_FULL);
+
+Validation Levels:
+
+- ``KAPI_VALIDATE_NONE``: No validation
+- ``KAPI_VALIDATE_BASIC``: Type and NULL checks only
+- ``KAPI_VALIDATE_NORMAL``: Basic + range and constraint checks
+- ``KAPI_VALIDATE_FULL``: All checks including custom validators
+
+Custom Validators
+-----------------
+
+APIs can register custom validation functions:
+
+.. code-block:: c
+
+ static bool validate_buffer_size(const struct kapi_param_spec *spec,
+ const void *value, void *context)
+ {
+ size_t size = *(size_t *)value;
+ struct my_context *ctx = context;
+
+ return size > 0 && size <= ctx->max_buffer_size;
+ }
+
+ KAPI_PARAM_CUSTOM_VALIDATOR(0, validate_buffer_size)
+
+DebugFS Interface
+=================
+
+The debugfs interface provides runtime access to API specifications:
+
+Directory Structure
+-------------------
+
+::
+
+ /sys/kernel/debug/kapi/
+ ├── apis/ # All registered APIs
+ │ ├── kmalloc/
+ │ │ ├── specification # Human-readable spec
+ │ │ ├── json # JSON format
+ │ │ └── xml # XML format
+ │ └── open/
+ │ └── ...
+ ├── summary # Overview of all APIs
+ ├── validation/ # Validation controls
+ │ ├── enabled # Global enable/disable
+ │ ├── level # Validation level
+ │ └── stats # Validation statistics
+ └── export/ # Bulk export options
+ ├── all.json # All specs in JSON
+ └── all.xml # All specs in XML
+
+Usage Examples
+--------------
+
+Query specific API::
+
+ $ cat /sys/kernel/debug/kapi/apis/kmalloc/specification
+ API: kmalloc
+ Version: 3.0
+ Description: Allocate kernel memory
+
+ Parameters:
+ [0] size (size_t, in): Number of bytes to allocate
+ Range: 0 - 4194304
+ [1] flags (flags, in): Allocation flags (GFP_*)
+ Mask: 0x1ffffff
+
+ Returns: pointer - Pointer to allocated memory or NULL
+
+ Errors:
+ ENOMEM: Out of memory
+
+ Context: process, softirq, hardirq
+
+ Side Effects:
+ - Allocates memory from kernel heap
+
+Export all specifications::
+
+ $ cat /sys/kernel/debug/kapi/export/all.json > kernel-apis.json
+
+Enable validation for specific API::
+
+ $ echo 1 > /sys/kernel/debug/kapi/apis/kmalloc/validate
+
+Performance Considerations
+==========================
+
+Memory Overhead
+---------------
+
+Each API specification consumes approximately 2-4KB of memory. With thousands
+of kernel APIs, this can add up to several megabytes. Consider:
+
+1. Building with ``CONFIG_KAPI_SPEC=n`` for production kernels
+2. Using ``__init`` annotations for APIs only used during boot
+3. Implementing lazy loading for rarely used specifications
+
+Runtime Overhead
+----------------
+
+When ``CONFIG_KAPI_RUNTIME_CHECKS`` is enabled:
+
+- Each validated API call adds 50-200ns overhead
+- Complex validations (custom validators) may add more
+- Use validation only in development/testing kernels
+
+Optimization Strategies
+-----------------------
+
+1. **Compile-time optimization**: When validation is disabled, all
+ validation code is optimized away by the compiler.
+
+2. **Selective validation**: Enable validation only for specific APIs
+ or subsystems under test.
+
+3. **Caching**: The framework caches validation results for repeated
+ calls with identical parameters.
+
+Documentation Generation
+------------------------
+
+The framework exports specifications via debugfs that can be used
+to generate documentation. Tools for automatic documentation generation
+from specifications are planned for future development.
+
+IDE Integration
+---------------
+
+Modern IDEs can use the JSON export for:
+
+- Parameter hints
+- Type checking
+- Context validation
+- Error code documentation
+
+Testing Framework
+-----------------
+
+The framework includes test helpers::
+
+ #ifdef CONFIG_KAPI_TESTING
+ /* Verify API behaves according to specification */
+ kapi_test_api("kmalloc", test_cases);
+ #endif
+
+Best Practices
+==============
+
+Writing Specifications
+----------------------
+
+1. **Be Comprehensive**: Document all parameters, errors, and side effects
+2. **Keep Updated**: Update specs when API behavior changes
+3. **Use Examples**: Include usage examples in descriptions
+4. **Validate Constraints**: Define realistic constraints for parameters
+5. **Document Context**: Clearly specify allowed execution contexts
+
+Maintenance
+-----------
+
+1. **Version Specifications**: Increment version when API changes
+2. **Deprecation**: Mark deprecated APIs and suggest replacements
+3. **Cross-reference**: Link related APIs in descriptions
+4. **Test Specifications**: Verify specs match implementation
+
+Common Patterns
+---------------
+
+**Optional Parameters**::
+
+ KAPI_PARAM(2, optional_arg, KAPI_TYPE_POINTER, KAPI_DIR_IN,
+ "Optional argument (may be NULL)")
+ KAPI_PARAM_OPTIONAL(2)
+
+**Variable Arguments**::
+
+ KAPI_PARAM(1, fmt, KAPI_TYPE_FORMAT_STRING, KAPI_DIR_IN,
+ "Printf-style format string")
+ KAPI_PARAM_VARIADIC(2, "Format arguments")
+
+**Callback Functions**::
+
+ KAPI_PARAM(1, callback, KAPI_TYPE_FUNCTION_PTR, KAPI_DIR_IN,
+ "Callback function")
+ KAPI_PARAM_CALLBACK(1, "int (*)(void *data)", "data")
+
+Troubleshooting
+===============
+
+Common Issues
+-------------
+
+**Specification Not Found**::
+
+ kernel: KAPI: Specification for 'my_api' not found
+
+ Solution: Ensure KAPI_DEFINE_SPEC is in the same translation unit
+ as the function implementation.
+
+**Validation Failures**::
+
+ kernel: KAPI: Validation failed for kmalloc parameter 'size':
+ value 5242880 exceeds maximum 4194304
+
+ Solution: Check parameter constraints or adjust specification if
+ the constraint is incorrect.
+
+**Build Errors**::
+
+ error: 'KAPI_TYPE_UNKNOWN' undeclared
+
+ Solution: Include <linux/kernel_api_spec.h> and ensure
+ CONFIG_KAPI_SPEC is enabled.
+
+Debug Options
+-------------
+
+Enable verbose debugging::
+
+ echo 8 > /proc/sys/kernel/printk
+ echo 1 > /sys/kernel/debug/kapi/debug/verbose
+
+Future Directions
+=================
+
+Planned Features
+----------------
+
+1. **Automatic Extraction**: Tool to extract specifications from existing
+ kernel-doc comments
+
+2. **Contract Verification**: Static analysis to verify implementation
+ matches specification
+
+3. **Performance Profiling**: Measure actual API performance against
+ documented expectations
+
+4. **Fuzzing Integration**: Use specifications to guide intelligent
+ fuzzing of kernel APIs
+
+5. **Version Compatibility**: Track API changes across kernel versions
+
+Research Areas
+--------------
+
+1. **Formal Verification**: Use specifications for mathematical proofs
+ of correctness
+
+2. **Runtime Monitoring**: Detect specification violations in production
+ with minimal overhead
+
+3. **API Evolution**: Analyze how kernel APIs change over time
+
+4. **Security Applications**: Use specifications for security policy
+ enforcement
+
+Contributing
+============
+
+Submitting Specifications
+-------------------------
+
+1. Add specifications to the same file as the API implementation
+2. Follow existing patterns and naming conventions
+3. Test with CONFIG_KAPI_RUNTIME_CHECKS enabled
+4. Verify debugfs output is correct
+5. Run scripts/checkpatch.pl on your changes
+
+Review Criteria
+---------------
+
+Specifications will be reviewed for:
+
+1. **Completeness**: All parameters and errors documented
+2. **Accuracy**: Specification matches implementation
+3. **Clarity**: Descriptions are clear and helpful
+4. **Consistency**: Follows framework conventions
+5. **Performance**: No unnecessary runtime overhead
+
+Contact
+-------
+
+- Maintainer: Sasha Levin <sashal@kernel.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index c3f7fbd0d67af..759f6c0b9a4dd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13047,6 +13047,15 @@ W: https://linuxtv.org
T: git git://linuxtv.org/media.git
F: drivers/media/radio/radio-keene*
+KERNEL API SPECIFICATION FRAMEWORK (KAPI)
+M: Sasha Levin <sashal@kernel.org>
+L: linux-api@vger.kernel.org
+S: Maintained
+F: Documentation/admin-guide/kernel-api-spec.rst
+F: include/linux/kernel_api_spec.h
+F: kernel/api/
+F: scripts/extract-kapi-spec.sh
+
KERNEL AUTOMOUNTER
M: Ian Kent <raven@themaw.net>
L: autofs@vger.kernel.org
diff --git a/arch/um/kernel/dyn.lds.S b/arch/um/kernel/dyn.lds.S
index a36b7918a011a..283ab11788d8c 100644
--- a/arch/um/kernel/dyn.lds.S
+++ b/arch/um/kernel/dyn.lds.S
@@ -102,6 +102,9 @@ SECTIONS
init.data : { INIT_DATA }
__init_end = .;
+ /* Kernel API specifications in dedicated section */
+ KAPI_SPECS_SECTION()
+
/* Ensure the __preinit_array_start label is properly aligned. We
could instead move the label definition inside the section, but
the linker would then create the section even if it turns out to
diff --git a/arch/um/kernel/uml.lds.S b/arch/um/kernel/uml.lds.S
index a409d4b66114f..e3850d8293436 100644
--- a/arch/um/kernel/uml.lds.S
+++ b/arch/um/kernel/uml.lds.S
@@ -74,6 +74,9 @@ SECTIONS
init.data : { INIT_DATA }
__init_end = .;
+ /* Kernel API specifications in dedicated section */
+ KAPI_SPECS_SECTION()
+
.data :
{
INIT_TASK_DATA(KERNEL_STACK_SIZE)
diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 4fa0be732af10..8cc508adc9d51 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -173,6 +173,9 @@ SECTIONS
RO_DATA(PAGE_SIZE)
X86_ALIGN_RODATA_END
+ /* Kernel API specifications in dedicated section */
+ KAPI_SPECS_SECTION()
+
/* Data */
.data : AT(ADDR(.data) - LOAD_OFFSET) {
/* Start of data section */
diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index fa5f19b8d53a0..7b47736057e01 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -279,6 +279,26 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG)
#define TRACE_SYSCALLS()
#endif
+#ifdef CONFIG_KAPI_SPEC
+#define KAPI_SPECS() \
+ . = ALIGN(8); \
+ __start_kapi_specs = .; \
+ KEEP(*(.kapi_specs)) \
+ __stop_kapi_specs = .;
+
+/* For placing KAPI specs in a dedicated section */
+#define KAPI_SPECS_SECTION() \
+ .kapi_specs : AT(ADDR(.kapi_specs) - LOAD_OFFSET) { \
+ . = ALIGN(8); \
+ __start_kapi_specs = .; \
+ KEEP(*(.kapi_specs)) \
+ __stop_kapi_specs = .; \
+ }
+#else
+#define KAPI_SPECS()
+#define KAPI_SPECS_SECTION()
+#endif
+
#ifdef CONFIG_BPF_EVENTS
#define BPF_RAW_TP() STRUCT_ALIGN(); \
BOUNDED_SECTION_BY(__bpf_raw_tp_map, __bpf_raw_tp)
diff --git a/include/linux/kernel_api_spec.h b/include/linux/kernel_api_spec.h
new file mode 100644
index 0000000000000..d8439d411f41e
--- /dev/null
+++ b/include/linux/kernel_api_spec.h
@@ -0,0 +1,1513 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * kernel_api_spec.h - Kernel API Formal Specification Framework
+ *
+ * This framework provides structures and macros to formally specify kernel APIs
+ * in both human and machine-readable formats. It supports comprehensive documentation
+ * of function signatures, parameters, return values, error conditions, and constraints.
+ */
+
+#ifndef _LINUX_KERNEL_API_SPEC_H
+#define _LINUX_KERNEL_API_SPEC_H
+
+#include <linux/types.h>
+#include <linux/stringify.h>
+#include <linux/compiler.h>
+
+struct sigaction;
+
+#define KAPI_MAX_PARAMS 16
+#define KAPI_MAX_ERRORS 32
+#define KAPI_MAX_CONSTRAINTS 16
+#define KAPI_MAX_SIGNALS 32
+#define KAPI_MAX_NAME_LEN 128
+#define KAPI_MAX_DESC_LEN 512
+#define KAPI_MAX_CAPABILITIES 8
+#define KAPI_MAX_SOCKET_STATES 16
+#define KAPI_MAX_PROTOCOL_BEHAVIORS 8
+#define KAPI_MAX_NET_ERRORS 16
+#define KAPI_MAX_SOCKOPTS 16
+#define KAPI_MAX_ADDR_FAMILIES 8
+
+/**
+ * enum kapi_param_type - Parameter type classification
+ * @KAPI_TYPE_VOID: void type
+ * @KAPI_TYPE_INT: Integer types (int, long, etc.)
+ * @KAPI_TYPE_UINT: Unsigned integer types
+ * @KAPI_TYPE_PTR: Pointer types
+ * @KAPI_TYPE_STRUCT: Structure types
+ * @KAPI_TYPE_UNION: Union types
+ * @KAPI_TYPE_ENUM: Enumeration types
+ * @KAPI_TYPE_FUNC_PTR: Function pointer types
+ * @KAPI_TYPE_ARRAY: Array types
+ * @KAPI_TYPE_FD: File descriptor - validated in process context
+ * @KAPI_TYPE_USER_PTR: User space pointer - validated for access and size
+ * @KAPI_TYPE_PATH: Pathname - validated for access and path limits
+ * @KAPI_TYPE_CUSTOM: Custom/complex types
+ */
+enum kapi_param_type {
+ KAPI_TYPE_VOID = 0,
+ KAPI_TYPE_INT,
+ KAPI_TYPE_UINT,
+ KAPI_TYPE_PTR,
+ KAPI_TYPE_STRUCT,
+ KAPI_TYPE_UNION,
+ KAPI_TYPE_ENUM,
+ KAPI_TYPE_FUNC_PTR,
+ KAPI_TYPE_ARRAY,
+ KAPI_TYPE_FD, /* File descriptor - validated in process context */
+ KAPI_TYPE_USER_PTR, /* User space pointer - validated for access and size */
+ KAPI_TYPE_PATH, /* Pathname - validated for access and path limits */
+ KAPI_TYPE_CUSTOM,
+};
+
+/**
+ * enum kapi_param_flags - Parameter attribute flags
+ * @KAPI_PARAM_IN: Input parameter
+ * @KAPI_PARAM_OUT: Output parameter
+ * @KAPI_PARAM_INOUT: Input/output parameter
+ * @KAPI_PARAM_OPTIONAL: Optional parameter (can be NULL)
+ * @KAPI_PARAM_CONST: Const qualified parameter
+ * @KAPI_PARAM_VOLATILE: Volatile qualified parameter
+ * @KAPI_PARAM_USER: User space pointer
+ * @KAPI_PARAM_DMA: DMA-capable memory required
+ * @KAPI_PARAM_ALIGNED: Alignment requirements
+ */
+enum kapi_param_flags {
+ KAPI_PARAM_IN = (1 << 0),
+ KAPI_PARAM_OUT = (1 << 1),
+ KAPI_PARAM_INOUT = (1 << 2),
+ KAPI_PARAM_OPTIONAL = (1 << 3),
+ KAPI_PARAM_CONST = (1 << 4),
+ KAPI_PARAM_VOLATILE = (1 << 5),
+ KAPI_PARAM_USER = (1 << 6),
+ KAPI_PARAM_DMA = (1 << 7),
+ KAPI_PARAM_ALIGNED = (1 << 8),
+};
+
+/**
+ * enum kapi_context_flags - Function execution context flags
+ * @KAPI_CTX_PROCESS: Can be called from process context
+ * @KAPI_CTX_SOFTIRQ: Can be called from softirq context
+ * @KAPI_CTX_HARDIRQ: Can be called from hardirq context
+ * @KAPI_CTX_NMI: Can be called from NMI context
+ * @KAPI_CTX_ATOMIC: Must be called in atomic context
+ * @KAPI_CTX_SLEEPABLE: May sleep
+ * @KAPI_CTX_PREEMPT_DISABLED: Requires preemption disabled
+ * @KAPI_CTX_IRQ_DISABLED: Requires interrupts disabled
+ */
+enum kapi_context_flags {
+ KAPI_CTX_PROCESS = (1 << 0),
+ KAPI_CTX_SOFTIRQ = (1 << 1),
+ KAPI_CTX_HARDIRQ = (1 << 2),
+ KAPI_CTX_NMI = (1 << 3),
+ KAPI_CTX_ATOMIC = (1 << 4),
+ KAPI_CTX_SLEEPABLE = (1 << 5),
+ KAPI_CTX_PREEMPT_DISABLED = (1 << 6),
+ KAPI_CTX_IRQ_DISABLED = (1 << 7),
+};
+
+/**
+ * enum kapi_lock_type - Lock types used/required by the function
+ * @KAPI_LOCK_NONE: No locking requirements
+ * @KAPI_LOCK_MUTEX: Mutex lock
+ * @KAPI_LOCK_SPINLOCK: Spinlock
+ * @KAPI_LOCK_RWLOCK: Read-write lock
+ * @KAPI_LOCK_SEQLOCK: Sequence lock
+ * @KAPI_LOCK_RCU: RCU lock
+ * @KAPI_LOCK_SEMAPHORE: Semaphore
+ * @KAPI_LOCK_CUSTOM: Custom locking mechanism
+ */
+enum kapi_lock_type {
+ KAPI_LOCK_NONE = 0,
+ KAPI_LOCK_MUTEX,
+ KAPI_LOCK_SPINLOCK,
+ KAPI_LOCK_RWLOCK,
+ KAPI_LOCK_SEQLOCK,
+ KAPI_LOCK_RCU,
+ KAPI_LOCK_SEMAPHORE,
+ KAPI_LOCK_CUSTOM,
+};
+
+/**
+ * enum kapi_constraint_type - Types of parameter constraints
+ * @KAPI_CONSTRAINT_NONE: No constraint
+ * @KAPI_CONSTRAINT_RANGE: Numeric range constraint
+ * @KAPI_CONSTRAINT_MASK: Bitmask constraint
+ * @KAPI_CONSTRAINT_ENUM: Enumerated values constraint
+ * @KAPI_CONSTRAINT_CUSTOM: Custom validation function
+ */
+enum kapi_constraint_type {
+ KAPI_CONSTRAINT_NONE = 0,
+ KAPI_CONSTRAINT_RANGE,
+ KAPI_CONSTRAINT_MASK,
+ KAPI_CONSTRAINT_ENUM,
+ KAPI_CONSTRAINT_CUSTOM,
+};
+
+/**
+ * struct kapi_param_spec - Parameter specification
+ * @name: Parameter name
+ * @type_name: Type name as string
+ * @type: Parameter type classification
+ * @flags: Parameter attribute flags
+ * @size: Size in bytes (for arrays/buffers)
+ * @alignment: Required alignment
+ * @min_value: Minimum valid value (for numeric types)
+ * @max_value: Maximum valid value (for numeric types)
+ * @valid_mask: Valid bits mask (for flag parameters)
+ * @enum_values: Array of valid enumerated values
+ * @enum_count: Number of valid enumerated values
+ * @constraint_type: Type of constraint applied
+ * @validate: Custom validation function
+ * @description: Human-readable description
+ * @constraints: Additional constraints description
+ * @size_param_idx: Index of parameter that determines size (-1 if fixed size)
+ * @size_multiplier: Multiplier for size calculation (e.g., sizeof(struct))
+ */
+struct kapi_param_spec {
+ char name[KAPI_MAX_NAME_LEN];
+ char type_name[KAPI_MAX_NAME_LEN];
+ enum kapi_param_type type;
+ u32 flags;
+ size_t size;
+ size_t alignment;
+ s64 min_value;
+ s64 max_value;
+ u64 valid_mask;
+ const s64 *enum_values;
+ u32 enum_count;
+ enum kapi_constraint_type constraint_type;
+ bool (*validate)(s64 value);
+ char description[KAPI_MAX_DESC_LEN];
+ char constraints[KAPI_MAX_DESC_LEN];
+ int size_param_idx; /* Index of param that determines size, -1 if N/A */
+ size_t size_multiplier; /* Size per unit (e.g., sizeof(struct epoll_event)) */
+} __attribute__((packed));
+
+/**
+ * struct kapi_error_spec - Error condition specification
+ * @error_code: Error code value
+ * @name: Error code name (e.g., "EINVAL")
+ * @condition: Condition that triggers this error
+ * @description: Detailed error description
+ */
+struct kapi_error_spec {
+ int error_code;
+ char name[KAPI_MAX_NAME_LEN];
+ char condition[KAPI_MAX_DESC_LEN];
+ char description[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * enum kapi_return_check_type - Return value check types
+ * @KAPI_RETURN_EXACT: Success is an exact value
+ * @KAPI_RETURN_RANGE: Success is within a range
+ * @KAPI_RETURN_ERROR_CHECK: Success is when NOT in error list
+ * @KAPI_RETURN_FD: Return value is a file descriptor (>= 0 is success)
+ * @KAPI_RETURN_CUSTOM: Custom validation function
+ */
+enum kapi_return_check_type {
+ KAPI_RETURN_EXACT,
+ KAPI_RETURN_RANGE,
+ KAPI_RETURN_ERROR_CHECK,
+ KAPI_RETURN_FD,
+ KAPI_RETURN_CUSTOM,
+};
+
+/**
+ * struct kapi_return_spec - Return value specification
+ * @type_name: Return type name
+ * @type: Return type classification
+ * @check_type: Type of success check to perform
+ * @success_value: Exact value indicating success (for EXACT)
+ * @success_min: Minimum success value (for RANGE)
+ * @success_max: Maximum success value (for RANGE)
+ * @error_values: Array of error values (for ERROR_CHECK)
+ * @error_count: Number of error values
+ * @is_success: Custom function to check success
+ * @description: Return value description
+ */
+struct kapi_return_spec {
+ char type_name[KAPI_MAX_NAME_LEN];
+ enum kapi_param_type type;
+ enum kapi_return_check_type check_type;
+ s64 success_value;
+ s64 success_min;
+ s64 success_max;
+ const s64 *error_values;
+ u32 error_count;
+ bool (*is_success)(s64 retval);
+ char description[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * struct kapi_lock_spec - Lock requirement specification
+ * @lock_name: Name of the lock
+ * @lock_type: Type of lock
+ * @acquired: Whether function acquires this lock
+ * @released: Whether function releases this lock
+ * @held_on_entry: Whether lock must be held on entry
+ * @held_on_exit: Whether lock is held on exit
+ * @description: Additional lock requirements
+ */
+struct kapi_lock_spec {
+ char lock_name[KAPI_MAX_NAME_LEN];
+ enum kapi_lock_type lock_type;
+ bool acquired;
+ bool released;
+ bool held_on_entry;
+ bool held_on_exit;
+ char description[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * struct kapi_constraint_spec - Additional constraint specification
+ * @name: Constraint name
+ * @description: Constraint description
+ * @expression: Formal expression (if applicable)
+ */
+struct kapi_constraint_spec {
+ char name[KAPI_MAX_NAME_LEN];
+ char description[KAPI_MAX_DESC_LEN];
+ char expression[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * enum kapi_signal_direction - Signal flow direction
+ * @KAPI_SIGNAL_RECEIVE: Function may receive this signal
+ * @KAPI_SIGNAL_SEND: Function may send this signal
+ * @KAPI_SIGNAL_HANDLE: Function handles this signal specially
+ * @KAPI_SIGNAL_BLOCK: Function blocks this signal
+ * @KAPI_SIGNAL_IGNORE: Function ignores this signal
+ */
+enum kapi_signal_direction {
+ KAPI_SIGNAL_RECEIVE = (1 << 0),
+ KAPI_SIGNAL_SEND = (1 << 1),
+ KAPI_SIGNAL_HANDLE = (1 << 2),
+ KAPI_SIGNAL_BLOCK = (1 << 3),
+ KAPI_SIGNAL_IGNORE = (1 << 4),
+};
+
+/**
+ * enum kapi_signal_action - What the function does with the signal
+ * @KAPI_SIGNAL_ACTION_DEFAULT: Default signal action applies
+ * @KAPI_SIGNAL_ACTION_TERMINATE: Causes termination
+ * @KAPI_SIGNAL_ACTION_COREDUMP: Causes termination with core dump
+ * @KAPI_SIGNAL_ACTION_STOP: Stops the process
+ * @KAPI_SIGNAL_ACTION_CONTINUE: Continues a stopped process
+ * @KAPI_SIGNAL_ACTION_CUSTOM: Custom handling described in notes
+ * @KAPI_SIGNAL_ACTION_RETURN: Returns from syscall with EINTR
+ * @KAPI_SIGNAL_ACTION_RESTART: Restarts the syscall
+ * @KAPI_SIGNAL_ACTION_QUEUE: Queues the signal for later delivery
+ * @KAPI_SIGNAL_ACTION_DISCARD: Discards the signal
+ * @KAPI_SIGNAL_ACTION_TRANSFORM: Transforms to another signal
+ */
+enum kapi_signal_action {
+ KAPI_SIGNAL_ACTION_DEFAULT = 0,
+ KAPI_SIGNAL_ACTION_TERMINATE,
+ KAPI_SIGNAL_ACTION_COREDUMP,
+ KAPI_SIGNAL_ACTION_STOP,
+ KAPI_SIGNAL_ACTION_CONTINUE,
+ KAPI_SIGNAL_ACTION_CUSTOM,
+ KAPI_SIGNAL_ACTION_RETURN,
+ KAPI_SIGNAL_ACTION_RESTART,
+ KAPI_SIGNAL_ACTION_QUEUE,
+ KAPI_SIGNAL_ACTION_DISCARD,
+ KAPI_SIGNAL_ACTION_TRANSFORM,
+};
+
+/**
+ * struct kapi_signal_spec - Signal specification
+ * @signal_num: Signal number (e.g., SIGKILL, SIGTERM)
+ * @signal_name: Signal name as string
+ * @direction: Direction flags (OR of kapi_signal_direction)
+ * @action: What happens when signal is received
+ * @target: Description of target process/thread for sent signals
+ * @condition: Condition under which signal is sent/received/handled
+ * @description: Detailed description of signal handling
+ * @restartable: Whether syscall is restartable after this signal
+ * @sa_flags_required: Required signal action flags (SA_*)
+ * @sa_flags_forbidden: Forbidden signal action flags
+ * @error_on_signal: Error code returned when signal occurs (-EINTR, etc)
+ * @transform_to: Signal number to transform to (if action is TRANSFORM)
+ * @timing: When signal can occur ("entry", "during", "exit", "anytime")
+ * @priority: Signal handling priority (lower processed first)
+ * @interruptible: Whether this operation is interruptible by this signal
+ * @queue_behavior: How signal is queued ("realtime", "standard", "coalesce")
+ * @state_required: Required process state for signal to be delivered
+ * @state_forbidden: Forbidden process state for signal delivery
+ */
+struct kapi_signal_spec {
+ int signal_num;
+ char signal_name[32];
+ u32 direction;
+ enum kapi_signal_action action;
+ char target[KAPI_MAX_DESC_LEN];
+ char condition[KAPI_MAX_DESC_LEN];
+ char description[KAPI_MAX_DESC_LEN];
+ bool restartable;
+ u32 sa_flags_required;
+ u32 sa_flags_forbidden;
+ int error_on_signal;
+ int transform_to;
+ char timing[32];
+ u8 priority;
+ bool interruptible;
+ char queue_behavior[128];
+ u32 state_required;
+ u32 state_forbidden;
+} __attribute__((packed));
+
+/**
+ * struct kapi_signal_mask_spec - Signal mask specification
+ * @mask_name: Name of the signal mask
+ * @signals: Array of signal numbers in the mask
+ * @signal_count: Number of signals in the mask
+ * @description: Description of what this mask represents
+ */
+struct kapi_signal_mask_spec {
+ char mask_name[KAPI_MAX_NAME_LEN];
+ int signals[KAPI_MAX_SIGNALS];
+ u32 signal_count;
+ char description[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * struct kapi_struct_field - Structure field specification
+ * @name: Field name
+ * @type: Field type classification
+ * @type_name: Type name as string
+ * @offset: Offset within structure
+ * @size: Size of field in bytes
+ * @flags: Field attribute flags
+ * @constraint_type: Type of constraint applied
+ * @min_value: Minimum valid value (for numeric types)
+ * @max_value: Maximum valid value (for numeric types)
+ * @valid_mask: Valid bits mask (for flag fields)
+ * @description: Field description
+ */
+struct kapi_struct_field {
+ char name[KAPI_MAX_NAME_LEN];
+ enum kapi_param_type type;
+ char type_name[KAPI_MAX_NAME_LEN];
+ size_t offset;
+ size_t size;
+ u32 flags;
+ enum kapi_constraint_type constraint_type;
+ s64 min_value;
+ s64 max_value;
+ u64 valid_mask;
+ char description[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * struct kapi_struct_spec - Structure type specification
+ * @name: Structure name
+ * @size: Total size of structure
+ * @alignment: Required alignment
+ * @field_count: Number of fields
+ * @fields: Field specifications
+ * @description: Structure description
+ */
+struct kapi_struct_spec {
+ char name[KAPI_MAX_NAME_LEN];
+ size_t size;
+ size_t alignment;
+ u32 field_count;
+ struct kapi_struct_field fields[KAPI_MAX_PARAMS];
+ char description[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * enum kapi_capability_action - What the capability allows
+ * @KAPI_CAP_BYPASS_CHECK: Bypasses a check entirely
+ * @KAPI_CAP_INCREASE_LIMIT: Increases or removes a limit
+ * @KAPI_CAP_OVERRIDE_RESTRICTION: Overrides a restriction
+ * @KAPI_CAP_GRANT_PERMISSION: Grants permission that would otherwise be denied
+ * @KAPI_CAP_MODIFY_BEHAVIOR: Changes the behavior of the operation
+ * @KAPI_CAP_ACCESS_RESOURCE: Allows access to restricted resources
+ * @KAPI_CAP_PERFORM_OPERATION: Allows performing a privileged operation
+ */
+enum kapi_capability_action {
+ KAPI_CAP_BYPASS_CHECK = 0,
+ KAPI_CAP_INCREASE_LIMIT,
+ KAPI_CAP_OVERRIDE_RESTRICTION,
+ KAPI_CAP_GRANT_PERMISSION,
+ KAPI_CAP_MODIFY_BEHAVIOR,
+ KAPI_CAP_ACCESS_RESOURCE,
+ KAPI_CAP_PERFORM_OPERATION,
+};
+
+/**
+ * struct kapi_capability_spec - Capability requirement specification
+ * @capability: The capability constant (e.g., CAP_IPC_LOCK)
+ * @cap_name: Capability name as string
+ * @action: What the capability allows (kapi_capability_action)
+ * @allows: Description of what the capability allows
+ * @without_cap: What happens without the capability
+ * @check_condition: Condition when capability is checked
+ * @priority: Check priority (lower checked first)
+ * @alternative: Alternative capabilities that can be used
+ * @alternative_count: Number of alternative capabilities
+ */
+struct kapi_capability_spec {
+ int capability;
+ char cap_name[KAPI_MAX_NAME_LEN];
+ enum kapi_capability_action action;
+ char allows[KAPI_MAX_DESC_LEN];
+ char without_cap[KAPI_MAX_DESC_LEN];
+ char check_condition[KAPI_MAX_DESC_LEN];
+ u8 priority;
+ int alternative[KAPI_MAX_CAPABILITIES];
+ u32 alternative_count;
+} __attribute__((packed));
+
+/**
+ * enum kapi_side_effect_type - Types of side effects
+ * @KAPI_EFFECT_NONE: No side effects
+ * @KAPI_EFFECT_ALLOC_MEMORY: Allocates memory
+ * @KAPI_EFFECT_FREE_MEMORY: Frees memory
+ * @KAPI_EFFECT_MODIFY_STATE: Modifies global/shared state
+ * @KAPI_EFFECT_SIGNAL_SEND: Sends signals
+ * @KAPI_EFFECT_FILE_POSITION: Modifies file position
+ * @KAPI_EFFECT_LOCK_ACQUIRE: Acquires locks
+ * @KAPI_EFFECT_LOCK_RELEASE: Releases locks
+ * @KAPI_EFFECT_RESOURCE_CREATE: Creates system resources (FDs, PIDs, etc)
+ * @KAPI_EFFECT_RESOURCE_DESTROY: Destroys system resources
+ * @KAPI_EFFECT_SCHEDULE: May cause scheduling/context switch
+ * @KAPI_EFFECT_HARDWARE: Interacts with hardware
+ * @KAPI_EFFECT_NETWORK: Network I/O operation
+ * @KAPI_EFFECT_FILESYSTEM: Filesystem modification
+ * @KAPI_EFFECT_PROCESS_STATE: Modifies process state
+ */
+enum kapi_side_effect_type {
+ KAPI_EFFECT_NONE = 0,
+ KAPI_EFFECT_ALLOC_MEMORY = (1 << 0),
+ KAPI_EFFECT_FREE_MEMORY = (1 << 1),
+ KAPI_EFFECT_MODIFY_STATE = (1 << 2),
+ KAPI_EFFECT_SIGNAL_SEND = (1 << 3),
+ KAPI_EFFECT_FILE_POSITION = (1 << 4),
+ KAPI_EFFECT_LOCK_ACQUIRE = (1 << 5),
+ KAPI_EFFECT_LOCK_RELEASE = (1 << 6),
+ KAPI_EFFECT_RESOURCE_CREATE = (1 << 7),
+ KAPI_EFFECT_RESOURCE_DESTROY = (1 << 8),
+ KAPI_EFFECT_SCHEDULE = (1 << 9),
+ KAPI_EFFECT_HARDWARE = (1 << 10),
+ KAPI_EFFECT_NETWORK = (1 << 11),
+ KAPI_EFFECT_FILESYSTEM = (1 << 12),
+ KAPI_EFFECT_PROCESS_STATE = (1 << 13),
+};
+
+/**
+ * struct kapi_side_effect - Side effect specification
+ * @type: Bitmask of effect types
+ * @target: What is affected (e.g., "process memory", "file descriptor table")
+ * @condition: Condition under which effect occurs
+ * @description: Detailed description of the effect
+ * @reversible: Whether the effect can be undone
+ */
+struct kapi_side_effect {
+ u32 type;
+ char target[KAPI_MAX_NAME_LEN];
+ char condition[KAPI_MAX_DESC_LEN];
+ char description[KAPI_MAX_DESC_LEN];
+ bool reversible;
+} __attribute__((packed));
+
+/**
+ * struct kapi_state_transition - State transition specification
+ * @from_state: Starting state description
+ * @to_state: Ending state description
+ * @condition: Condition for transition
+ * @object: Object whose state changes
+ * @description: Detailed description
+ */
+struct kapi_state_transition {
+ char from_state[KAPI_MAX_NAME_LEN];
+ char to_state[KAPI_MAX_NAME_LEN];
+ char condition[KAPI_MAX_DESC_LEN];
+ char object[KAPI_MAX_NAME_LEN];
+ char description[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+#define KAPI_MAX_STRUCT_SPECS 8
+#define KAPI_MAX_SIDE_EFFECTS 16
+#define KAPI_MAX_STATE_TRANS 8
+
+#ifdef CONFIG_NET
+/**
+ * enum kapi_socket_state - Socket states for state machine
+ */
+enum kapi_socket_state {
+ KAPI_SOCK_STATE_UNSPEC = 0,
+ KAPI_SOCK_STATE_CLOSED,
+ KAPI_SOCK_STATE_OPEN,
+ KAPI_SOCK_STATE_BOUND,
+ KAPI_SOCK_STATE_LISTEN,
+ KAPI_SOCK_STATE_SYN_SENT,
+ KAPI_SOCK_STATE_SYN_RECV,
+ KAPI_SOCK_STATE_ESTABLISHED,
+ KAPI_SOCK_STATE_FIN_WAIT1,
+ KAPI_SOCK_STATE_FIN_WAIT2,
+ KAPI_SOCK_STATE_CLOSE_WAIT,
+ KAPI_SOCK_STATE_CLOSING,
+ KAPI_SOCK_STATE_LAST_ACK,
+ KAPI_SOCK_STATE_TIME_WAIT,
+ KAPI_SOCK_STATE_CONNECTED,
+ KAPI_SOCK_STATE_DISCONNECTED,
+};
+
+/**
+ * enum kapi_socket_protocol - Socket protocol types
+ */
+enum kapi_socket_protocol {
+ KAPI_PROTO_TCP = (1 << 0),
+ KAPI_PROTO_UDP = (1 << 1),
+ KAPI_PROTO_UNIX = (1 << 2),
+ KAPI_PROTO_RAW = (1 << 3),
+ KAPI_PROTO_PACKET = (1 << 4),
+ KAPI_PROTO_NETLINK = (1 << 5),
+ KAPI_PROTO_SCTP = (1 << 6),
+ KAPI_PROTO_DCCP = (1 << 7),
+ KAPI_PROTO_ALL = 0xFFFFFFFF,
+};
+
+/**
+ * enum kapi_buffer_behavior - Network buffer handling behaviors
+ */
+enum kapi_buffer_behavior {
+ KAPI_BUF_PEEK = (1 << 0),
+ KAPI_BUF_TRUNCATE = (1 << 1),
+ KAPI_BUF_SCATTER = (1 << 2),
+ KAPI_BUF_ZERO_COPY = (1 << 3),
+ KAPI_BUF_KERNEL_ALLOC = (1 << 4),
+ KAPI_BUF_DMA_CAPABLE = (1 << 5),
+ KAPI_BUF_FRAGMENT = (1 << 6),
+};
+
+/**
+ * enum kapi_async_behavior - Asynchronous operation behaviors
+ */
+enum kapi_async_behavior {
+ KAPI_ASYNC_BLOCK = 0,
+ KAPI_ASYNC_NONBLOCK = (1 << 0),
+ KAPI_ASYNC_POLL_READY = (1 << 1),
+ KAPI_ASYNC_SIGNAL_DRIVEN = (1 << 2),
+ KAPI_ASYNC_AIO = (1 << 3),
+ KAPI_ASYNC_IO_URING = (1 << 4),
+ KAPI_ASYNC_EPOLL = (1 << 5),
+};
+
+/**
+ * struct kapi_socket_state_spec - Socket state requirement/transition
+ */
+struct kapi_socket_state_spec {
+ enum kapi_socket_state required_states[KAPI_MAX_SOCKET_STATES];
+ u32 required_state_count;
+ enum kapi_socket_state forbidden_states[KAPI_MAX_SOCKET_STATES];
+ u32 forbidden_state_count;
+ enum kapi_socket_state resulting_state;
+ char state_condition[KAPI_MAX_DESC_LEN];
+ u32 applicable_protocols;
+} __attribute__((packed));
+
+/**
+ * struct kapi_protocol_behavior - Protocol-specific behavior
+ */
+struct kapi_protocol_behavior {
+ u32 applicable_protocols;
+ char behavior[KAPI_MAX_DESC_LEN];
+ s64 protocol_flags;
+ char flag_description[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * struct kapi_buffer_spec - Network buffer specification
+ */
+struct kapi_buffer_spec {
+ u32 buffer_behaviors;
+ size_t min_buffer_size;
+ size_t max_buffer_size;
+ size_t optimal_buffer_size;
+ char fragmentation_rules[KAPI_MAX_DESC_LEN];
+ bool can_partial_transfer;
+ char partial_transfer_rules[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * struct kapi_async_spec - Asynchronous behavior specification
+ */
+struct kapi_async_spec {
+ enum kapi_async_behavior supported_modes;
+ int nonblock_errno;
+ u32 poll_events_in;
+ u32 poll_events_out;
+ char completion_condition[KAPI_MAX_DESC_LEN];
+ bool supports_timeout;
+ char timeout_behavior[KAPI_MAX_DESC_LEN];
+} __attribute__((packed));
+
+/**
+ * struct kapi_addr_family_spec - Address family specification
+ */
+struct kapi_addr_family_spec {
+ int family;
+ char family_name[32];
+ size_t addr_struct_size;
+ size_t min_addr_len;
+ size_t max_addr_len;
+ char addr_format[KAPI_MAX_DESC_LEN];
+ bool supports_wildcard;
+ bool supports_multicast;
+ bool supports_broadcast;
+ char special_addresses[KAPI_MAX_DESC_LEN];
+ u32 port_range_min;
+ u32 port_range_max;
+} __attribute__((packed));
+#endif /* CONFIG_NET */
+
+/**
+ * struct kernel_api_spec - Complete kernel API specification
+ * @name: Function name
+ * @version: API version
+ * @description: Brief description
+ * @long_description: Detailed description
+ * @context_flags: Execution context flags
+ * @param_count: Number of parameters
+ * @params: Parameter specifications
+ * @return_spec: Return value specification
+ * @error_count: Number of possible errors
+ * @errors: Error specifications
+ * @lock_count: Number of lock specifications
+ * @locks: Lock requirement specifications
+ * @constraint_count: Number of additional constraints
+ * @constraints: Additional constraint specifications
+ * @examples: Usage examples
+ * @notes: Additional notes
+ * @since_version: Kernel version when introduced
+ * @deprecated: Whether API is deprecated
+ * @replacement: Replacement API if deprecated
+ * @signal_count: Number of signal specifications
+ * @signals: Signal handling specifications
+ * @signal_mask_count: Number of signal mask specifications
+ * @signal_masks: Signal mask specifications
+ * @struct_spec_count: Number of structure specifications
+ * @struct_specs: Structure type specifications
+ * @side_effect_count: Number of side effect specifications
+ * @side_effects: Side effect specifications
+ * @state_trans_count: Number of state transition specifications
+ * @state_transitions: State transition specifications
+ */
+struct kernel_api_spec {
+ char name[KAPI_MAX_NAME_LEN];
+ u32 version;
+ char description[KAPI_MAX_DESC_LEN];
+ char long_description[KAPI_MAX_DESC_LEN * 4];
+ u32 context_flags;
+
+ /* Parameters */
+ u32 param_count;
+ struct kapi_param_spec params[KAPI_MAX_PARAMS];
+
+ /* Return value */
+ struct kapi_return_spec return_spec;
+
+ /* Errors */
+ u32 error_count;
+ struct kapi_error_spec errors[KAPI_MAX_ERRORS];
+
+ /* Locking */
+ u32 lock_count;
+ struct kapi_lock_spec locks[KAPI_MAX_CONSTRAINTS];
+
+ /* Constraints */
+ u32 constraint_count;
+ struct kapi_constraint_spec constraints[KAPI_MAX_CONSTRAINTS];
+
+ /* Additional information */
+ char examples[KAPI_MAX_DESC_LEN * 2];
+ char notes[KAPI_MAX_DESC_LEN * 2];
+ char since_version[32];
+ bool deprecated;
+ char replacement[KAPI_MAX_NAME_LEN];
+
+ /* Signal specifications */
+ u32 signal_count;
+ struct kapi_signal_spec signals[KAPI_MAX_SIGNALS];
+
+ /* Signal mask specifications */
+ u32 signal_mask_count;
+ struct kapi_signal_mask_spec signal_masks[KAPI_MAX_SIGNALS];
+
+ /* Structure specifications */
+ u32 struct_spec_count;
+ struct kapi_struct_spec struct_specs[KAPI_MAX_STRUCT_SPECS];
+
+ /* Side effects */
+ u32 side_effect_count;
+ struct kapi_side_effect side_effects[KAPI_MAX_SIDE_EFFECTS];
+
+ /* State transitions */
+ u32 state_trans_count;
+ struct kapi_state_transition state_transitions[KAPI_MAX_STATE_TRANS];
+
+ /* Capability specifications */
+ u32 capability_count;
+ struct kapi_capability_spec capabilities[KAPI_MAX_CAPABILITIES];
+
+#ifdef CONFIG_NET
+ /* Networking-specific fields */
+ struct kapi_socket_state_spec socket_state;
+ struct kapi_protocol_behavior protocol_behaviors[KAPI_MAX_PROTOCOL_BEHAVIORS];
+ u32 protocol_behavior_count;
+ struct kapi_buffer_spec buffer_spec;
+ struct kapi_async_spec async_spec;
+ struct kapi_addr_family_spec addr_families[KAPI_MAX_ADDR_FAMILIES];
+ u32 addr_family_count;
+
+ /* Network operation characteristics */
+ bool is_connection_oriented;
+ bool is_message_oriented;
+ bool supports_oob_data;
+ bool supports_peek;
+ bool supports_select_poll;
+ bool is_reentrant;
+
+ /* Network semantic descriptions */
+ char connection_establishment[KAPI_MAX_DESC_LEN];
+ char connection_termination[KAPI_MAX_DESC_LEN];
+ char data_transfer_semantics[KAPI_MAX_DESC_LEN];
+#endif /* CONFIG_NET */
+} __attribute__((packed));
+
+/* Macros for defining API specifications */
+
+/**
+ * DEFINE_KERNEL_API_SPEC - Define a kernel API specification
+ * @func_name: Function name to specify
+ */
+#define DEFINE_KERNEL_API_SPEC(func_name) \
+ static struct kernel_api_spec __kapi_spec_##func_name \
+ __used __section(".kapi_specs") = { \
+ .name = __stringify(func_name), \
+ .version = 1,
+
+#define KAPI_END_SPEC };
+
+/**
+ * KAPI_DESCRIPTION - Set API description
+ * @desc: Description string
+ */
+#define KAPI_DESCRIPTION(desc) \
+ .description = desc,
+
+/**
+ * KAPI_LONG_DESC - Set detailed API description
+ * @desc: Detailed description string
+ */
+#define KAPI_LONG_DESC(desc) \
+ .long_description = desc,
+
+/**
+ * KAPI_CONTEXT - Set execution context flags
+ * @flags: Context flags (OR'ed KAPI_CTX_* values)
+ */
+#define KAPI_CONTEXT(flags) \
+ .context_flags = flags,
+
+/**
+ * KAPI_PARAM - Define a parameter specification
+ * @idx: Parameter index (0-based)
+ * @pname: Parameter name
+ * @ptype: Type name string
+ * @pdesc: Parameter description
+ */
+#define KAPI_PARAM(idx, pname, ptype, pdesc) \
+ .params[idx] = { \
+ .name = pname, \
+ .type_name = ptype, \
+ .description = pdesc, \
+ .size_param_idx = -1, /* Default: no dynamic sizing */
+
+#define KAPI_PARAM_TYPE(ptype) \
+ .type = ptype,
+
+#define KAPI_PARAM_FLAGS(pflags) \
+ .flags = pflags,
+
+#define KAPI_PARAM_SIZE(psize) \
+ .size = psize,
+
+#define KAPI_PARAM_RANGE(pmin, pmax) \
+ .min_value = pmin, \
+ .max_value = pmax,
+
+#define KAPI_PARAM_CONSTRAINT_TYPE(ctype) \
+ .constraint_type = ctype,
+
+#define KAPI_PARAM_CONSTRAINT(desc) \
+ .constraints = desc,
+
+#define KAPI_PARAM_VALID_MASK(mask) \
+ .valid_mask = mask,
+
+#define KAPI_PARAM_ENUM_VALUES(values) \
+ .enum_values = values, \
+ .enum_count = ARRAY_SIZE(values),
+
+#define KAPI_PARAM_END },
+
+/**
+ * KAPI_RETURN - Define return value specification
+ * @rtype: Return type name
+ * @rdesc: Return value description
+ */
+#define KAPI_RETURN(rtype, rdesc) \
+ .return_spec = { \
+ .type_name = rtype, \
+ .description = rdesc,
+
+#define KAPI_RETURN_SUCCESS(val) \
+ .success_value = val,
+
+#define KAPI_RETURN_TYPE(rtype) \
+ .type = rtype,
+
+#define KAPI_RETURN_CHECK_TYPE(ctype) \
+ .check_type = ctype,
+
+#define KAPI_RETURN_ERROR_VALUES(values) \
+ .error_values = values,
+
+#define KAPI_RETURN_ERROR_COUNT(count) \
+ .error_count = count,
+
+#define KAPI_RETURN_SUCCESS_RANGE(min, max) \
+ .success_min = min, \
+ .success_max = max,
+
+#define KAPI_RETURN_END },
+
+/**
+ * KAPI_ERROR - Define an error condition
+ * @idx: Error index
+ * @ecode: Error code value
+ * @ename: Error name
+ * @econd: Error condition
+ * @edesc: Error description
+ */
+#define KAPI_ERROR(idx, ecode, ename, econd, edesc) \
+ .errors[idx] = { \
+ .error_code = ecode, \
+ .name = ename, \
+ .condition = econd, \
+ .description = edesc, \
+ },
+
+/**
+ * KAPI_LOCK - Define a lock requirement
+ * @idx: Lock index
+ * @lname: Lock name
+ * @ltype: Lock type
+ */
+#define KAPI_LOCK(idx, lname, ltype) \
+ .locks[idx] = { \
+ .lock_name = lname, \
+ .lock_type = ltype,
+
+#define KAPI_LOCK_ACQUIRED \
+ .acquired = true,
+
+#define KAPI_LOCK_RELEASED \
+ .released = true,
+
+#define KAPI_LOCK_HELD_ENTRY \
+ .held_on_entry = true,
+
+#define KAPI_LOCK_HELD_EXIT \
+ .held_on_exit = true,
+
+#define KAPI_LOCK_DESC(ldesc) \
+ .description = ldesc,
+
+#define KAPI_LOCK_END },
+
+/**
+ * KAPI_CONSTRAINT - Define an additional constraint
+ * @idx: Constraint index
+ * @cname: Constraint name
+ * @cdesc: Constraint description
+ */
+#define KAPI_CONSTRAINT(idx, cname, cdesc) \
+ .constraints[idx] = { \
+ .name = cname, \
+ .description = cdesc,
+
+#define KAPI_CONSTRAINT_EXPR(expr) \
+ .expression = expr,
+
+#define KAPI_CONSTRAINT_END },
+
+/**
+ * KAPI_EXAMPLES - Set API usage examples
+ * @examples: Examples string
+ */
+#define KAPI_EXAMPLES(ex) \
+ .examples = ex,
+
+/**
+ * KAPI_NOTES - Set API notes
+ * @notes: Notes string
+ */
+#define KAPI_NOTES(n) \
+ .notes = n,
+
+/**
+ * KAPI_SIGNAL - Define a signal specification
+ * @idx: Signal index
+ * @signum: Signal number (e.g., SIGKILL)
+ * @signame: Signal name string
+ * @dir: Direction flags
+ * @act: Action taken
+ */
+#define KAPI_SIGNAL(idx, signum, signame, dir, act) \
+ .signals[idx] = { \
+ .signal_num = signum, \
+ .signal_name = signame, \
+ .direction = dir, \
+ .action = act,
+
+#define KAPI_SIGNAL_TARGET(tgt) \
+ .target = tgt,
+
+#define KAPI_SIGNAL_CONDITION(cond) \
+ .condition = cond,
+
+#define KAPI_SIGNAL_DESC(desc) \
+ .description = desc,
+
+#define KAPI_SIGNAL_RESTARTABLE \
+ .restartable = true,
+
+#define KAPI_SIGNAL_SA_FLAGS_REQ(flags) \
+ .sa_flags_required = flags,
+
+#define KAPI_SIGNAL_SA_FLAGS_FORBID(flags) \
+ .sa_flags_forbidden = flags,
+
+#define KAPI_SIGNAL_ERROR(err) \
+ .error_on_signal = err,
+
+#define KAPI_SIGNAL_TRANSFORM(sig) \
+ .transform_to = sig,
+
+#define KAPI_SIGNAL_TIMING(when) \
+ .timing = when,
+
+#define KAPI_SIGNAL_PRIORITY(prio) \
+ .priority = prio,
+
+#define KAPI_SIGNAL_INTERRUPTIBLE \
+ .interruptible = true,
+
+#define KAPI_SIGNAL_QUEUE(behavior) \
+ .queue_behavior = behavior,
+
+#define KAPI_SIGNAL_STATE_REQ(state) \
+ .state_required = state,
+
+#define KAPI_SIGNAL_STATE_FORBID(state) \
+ .state_forbidden = state,
+
+#define KAPI_SIGNAL_END },
+
+#define KAPI_SIGNAL_COUNT(n) \
+ .signal_count = n,
+
+/**
+ * KAPI_SIGNAL_MASK - Define a signal mask specification
+ * @idx: Mask index
+ * @name: Mask name
+ * @desc: Mask description
+ */
+#define KAPI_SIGNAL_MASK(idx, name, desc) \
+ .signal_masks[idx] = { \
+ .mask_name = name, \
+ .description = desc,
+
+#define KAPI_SIGNAL_MASK_ADD(signum) \
+ .signals[.signal_count++] = signum,
+
+#define KAPI_SIGNAL_MASK_END },
+
+/**
+ * KAPI_STRUCT_SPEC - Define a structure specification
+ * @idx: Structure spec index
+ * @sname: Structure name
+ * @sdesc: Structure description
+ */
+#define KAPI_STRUCT_SPEC(idx, sname, sdesc) \
+ .struct_specs[idx] = { \
+ .name = #sname, \
+ .description = sdesc,
+
+#define KAPI_STRUCT_SIZE(ssize, salign) \
+ .size = ssize, \
+ .alignment = salign,
+
+#define KAPI_STRUCT_FIELD_COUNT(n) \
+ .field_count = n,
+
+/**
+ * KAPI_STRUCT_FIELD - Define a structure field
+ * @fidx: Field index
+ * @fname: Field name
+ * @ftype: Field type (KAPI_TYPE_*)
+ * @ftype_name: Type name as string
+ * @fdesc: Field description
+ */
+#define KAPI_STRUCT_FIELD(fidx, fname, ftype, ftype_name, fdesc) \
+ .fields[fidx] = { \
+ .name = fname, \
+ .type = ftype, \
+ .type_name = ftype_name, \
+ .description = fdesc,
+
+#define KAPI_FIELD_OFFSET(foffset) \
+ .offset = foffset,
+
+#define KAPI_FIELD_SIZE(fsize) \
+ .size = fsize,
+
+#define KAPI_FIELD_FLAGS(fflags) \
+ .flags = fflags,
+
+#define KAPI_FIELD_CONSTRAINT_RANGE(min, max) \
+ .constraint_type = KAPI_CONSTRAINT_RANGE, \
+ .min_value = min, \
+ .max_value = max,
+
+#define KAPI_FIELD_CONSTRAINT_MASK(mask) \
+ .constraint_type = KAPI_CONSTRAINT_MASK, \
+ .valid_mask = mask,
+
+#define KAPI_FIELD_CONSTRAINT_ENUM(values, count) \
+ .constraint_type = KAPI_CONSTRAINT_ENUM, \
+ .enum_values = values, \
+ .enum_count = count,
+
+#define KAPI_STRUCT_FIELD_END },
+
+#define KAPI_STRUCT_SPEC_END },
+
+/* Counter for structure specifications */
+#define KAPI_STRUCT_SPEC_COUNT(n) \
+ .struct_spec_count = n,
+
+/* Additional lock-related macros */
+#define KAPI_LOCK_COUNT(n) \
+ .lock_count = n,
+
+/**
+ * KAPI_SIDE_EFFECT - Define a side effect
+ * @idx: Side effect index
+ * @etype: Effect type bitmask (OR'ed KAPI_EFFECT_* values)
+ * @etarget: What is affected
+ * @edesc: Effect description
+ */
+#define KAPI_SIDE_EFFECT(idx, etype, etarget, edesc) \
+ .side_effects[idx] = { \
+ .type = etype, \
+ .target = etarget, \
+ .description = edesc, \
+ .reversible = false, /* Default to non-reversible */
+
+#define KAPI_EFFECT_CONDITION(cond) \
+ .condition = cond,
+
+#define KAPI_EFFECT_REVERSIBLE \
+ .reversible = true,
+
+#define KAPI_SIDE_EFFECT_END },
+
+/**
+ * KAPI_STATE_TRANS - Define a state transition
+ * @idx: State transition index
+ * @obj: Object whose state changes
+ * @from: From state
+ * @to: To state
+ * @desc: Transition description
+ */
+#define KAPI_STATE_TRANS(idx, obj, from, to, desc) \
+ .state_transitions[idx] = { \
+ .object = obj, \
+ .from_state = from, \
+ .to_state = to, \
+ .description = desc,
+
+#define KAPI_STATE_TRANS_COND(cond) \
+ .condition = cond,
+
+#define KAPI_STATE_TRANS_END },
+
+/* Counters for side effects and state transitions */
+#define KAPI_SIDE_EFFECT_COUNT(n) \
+ .side_effect_count = n,
+
+#define KAPI_STATE_TRANS_COUNT(n) \
+ .state_trans_count = n,
+
+/* Helper macros for common side effect patterns */
+#define KAPI_EFFECTS_MEMORY (KAPI_EFFECT_ALLOC_MEMORY | KAPI_EFFECT_FREE_MEMORY)
+#define KAPI_EFFECTS_LOCKING (KAPI_EFFECT_LOCK_ACQUIRE | KAPI_EFFECT_LOCK_RELEASE)
+#define KAPI_EFFECTS_RESOURCES (KAPI_EFFECT_RESOURCE_CREATE | KAPI_EFFECT_RESOURCE_DESTROY)
+#define KAPI_EFFECTS_IO (KAPI_EFFECT_NETWORK | KAPI_EFFECT_FILESYSTEM)
+
+/* Helper macros for common patterns */
+
+#define KAPI_PARAM_IN (KAPI_PARAM_IN)
+#define KAPI_PARAM_OUT (KAPI_PARAM_OUT)
+#define KAPI_PARAM_INOUT (KAPI_PARAM_IN | KAPI_PARAM_OUT)
+#define KAPI_PARAM_OPTIONAL (KAPI_PARAM_OPTIONAL)
+#define KAPI_PARAM_USER_PTR (KAPI_PARAM_USER | KAPI_PARAM_PTR)
+
+/* Common signal timing constants */
+#define KAPI_SIGNAL_TIME_ENTRY "entry"
+#define KAPI_SIGNAL_TIME_DURING "during"
+#define KAPI_SIGNAL_TIME_EXIT "exit"
+#define KAPI_SIGNAL_TIME_ANYTIME "anytime"
+#define KAPI_SIGNAL_TIME_BLOCKING "while_blocked"
+#define KAPI_SIGNAL_TIME_SLEEPING "while_sleeping"
+
+/* Common signal queue behaviors */
+#define KAPI_SIGNAL_QUEUE_STANDARD "standard"
+#define KAPI_SIGNAL_QUEUE_REALTIME "realtime"
+#define KAPI_SIGNAL_QUEUE_COALESCE "coalesce"
+#define KAPI_SIGNAL_QUEUE_REPLACE "replace"
+#define KAPI_SIGNAL_QUEUE_DISCARD "discard"
+
+/* Process state flags for signal delivery */
+#define KAPI_SIGNAL_STATE_RUNNING (1 << 0)
+#define KAPI_SIGNAL_STATE_SLEEPING (1 << 1)
+#define KAPI_SIGNAL_STATE_STOPPED (1 << 2)
+#define KAPI_SIGNAL_STATE_TRACED (1 << 3)
+#define KAPI_SIGNAL_STATE_ZOMBIE (1 << 4)
+#define KAPI_SIGNAL_STATE_DEAD (1 << 5)
+
+/* Capability specification macros */
+
+/**
+ * KAPI_CAPABILITY - Define a capability requirement
+ * @idx: Capability index
+ * @cap: Capability constant (e.g., CAP_IPC_LOCK)
+ * @name: Capability name string
+ * @act: Action type (kapi_capability_action)
+ */
+#define KAPI_CAPABILITY(idx, cap, name, act) \
+ .capabilities[idx] = { \
+ .capability = cap, \
+ .cap_name = name, \
+ .action = act,
+
+#define KAPI_CAP_ALLOWS(desc) \
+ .allows = desc,
+
+#define KAPI_CAP_WITHOUT(desc) \
+ .without_cap = desc,
+
+#define KAPI_CAP_CONDITION(cond) \
+ .check_condition = cond,
+
+#define KAPI_CAP_PRIORITY(prio) \
+ .priority = prio,
+
+#define KAPI_CAP_ALTERNATIVE(caps, count) \
+ .alternative = caps, \
+ .alternative_count = count,
+
+#define KAPI_CAPABILITY_END },
+
+/* Counter for capability specifications */
+#define KAPI_CAPABILITY_COUNT(n) \
+ .capability_count = n,
+
+/* Common signal patterns for syscalls */
+#define KAPI_SIGNAL_INTERRUPTIBLE_SLEEP \
+ KAPI_SIGNAL(0, SIGINT, "SIGINT", KAPI_SIGNAL_RECEIVE, KAPI_SIGNAL_ACTION_RETURN) \
+ KAPI_SIGNAL_TIMING(KAPI_SIGNAL_TIME_SLEEPING) \
+ KAPI_SIGNAL_ERROR(-EINTR) \
+ KAPI_SIGNAL_RESTARTABLE \
+ KAPI_SIGNAL_DESC("Interrupts sleep, returns -EINTR") \
+ KAPI_SIGNAL_END, \
+ KAPI_SIGNAL(1, SIGTERM, "SIGTERM", KAPI_SIGNAL_RECEIVE, KAPI_SIGNAL_ACTION_RETURN) \
+ KAPI_SIGNAL_TIMING(KAPI_SIGNAL_TIME_SLEEPING) \
+ KAPI_SIGNAL_ERROR(-EINTR) \
+ KAPI_SIGNAL_RESTARTABLE \
+ KAPI_SIGNAL_DESC("Interrupts sleep, returns -EINTR") \
+ KAPI_SIGNAL_END
+
+#define KAPI_SIGNAL_FATAL_DEFAULT \
+ KAPI_SIGNAL(2, SIGKILL, "SIGKILL", KAPI_SIGNAL_RECEIVE, KAPI_SIGNAL_ACTION_TERMINATE) \
+ KAPI_SIGNAL_TIMING(KAPI_SIGNAL_TIME_ANYTIME) \
+ KAPI_SIGNAL_PRIORITY(0) \
+ KAPI_SIGNAL_DESC("Process terminated immediately") \
+ KAPI_SIGNAL_END
+
+#define KAPI_SIGNAL_STOP_CONT \
+ KAPI_SIGNAL(3, SIGSTOP, "SIGSTOP", KAPI_SIGNAL_RECEIVE, KAPI_SIGNAL_ACTION_STOP) \
+ KAPI_SIGNAL_TIMING(KAPI_SIGNAL_TIME_ANYTIME) \
+ KAPI_SIGNAL_DESC("Process stopped") \
+ KAPI_SIGNAL_END, \
+ KAPI_SIGNAL(4, SIGCONT, "SIGCONT", KAPI_SIGNAL_RECEIVE, KAPI_SIGNAL_ACTION_CONTINUE) \
+ KAPI_SIGNAL_TIMING(KAPI_SIGNAL_TIME_ANYTIME) \
+ KAPI_SIGNAL_DESC("Process continued") \
+ KAPI_SIGNAL_END
+
+/* Validation and runtime checking */
+
+#ifdef CONFIG_KAPI_RUNTIME_CHECKS
+bool kapi_validate_params(const struct kernel_api_spec *spec, ...);
+bool kapi_validate_param(const struct kapi_param_spec *param_spec, s64 value);
+bool kapi_validate_param_with_context(const struct kapi_param_spec *param_spec,
+ s64 value, const s64 *all_params, int param_count);
+int kapi_validate_syscall_param(const struct kernel_api_spec *spec,
+ int param_idx, s64 value);
+int kapi_validate_syscall_params(const struct kernel_api_spec *spec,
+ const s64 *params, int param_count);
+bool kapi_check_return_success(const struct kapi_return_spec *return_spec, s64 retval);
+bool kapi_validate_return_value(const struct kernel_api_spec *spec, s64 retval);
+int kapi_validate_syscall_return(const struct kernel_api_spec *spec, s64 retval);
+void kapi_check_context(const struct kernel_api_spec *spec);
+void kapi_check_locks(const struct kernel_api_spec *spec);
+bool kapi_check_signal_allowed(const struct kernel_api_spec *spec, int signum);
+bool kapi_validate_signal_action(const struct kernel_api_spec *spec, int signum,
+ struct sigaction *act);
+int kapi_get_signal_error(const struct kernel_api_spec *spec, int signum);
+bool kapi_is_signal_restartable(const struct kernel_api_spec *spec, int signum);
+#else
+static inline bool kapi_validate_params(const struct kernel_api_spec *spec, ...)
+{
+ return true;
+}
+static inline bool kapi_validate_param(const struct kapi_param_spec *param_spec, s64 value)
+{
+ return true;
+}
+static inline bool kapi_validate_param_with_context(const struct kapi_param_spec *param_spec,
+ s64 value, const s64 *all_params, int param_count)
+{
+ return true;
+}
+static inline int kapi_validate_syscall_param(const struct kernel_api_spec *spec,
+ int param_idx, s64 value)
+{
+ return 0;
+}
+static inline int kapi_validate_syscall_params(const struct kernel_api_spec *spec,
+ const s64 *params, int param_count)
+{
+ return 0;
+}
+static inline bool kapi_check_return_success(const struct kapi_return_spec *return_spec, s64 retval)
+{
+ return true;
+}
+static inline bool kapi_validate_return_value(const struct kernel_api_spec *spec, s64 retval)
+{
+ return true;
+}
+static inline int kapi_validate_syscall_return(const struct kernel_api_spec *spec, s64 retval)
+{
+ return 0;
+}
+static inline void kapi_check_context(const struct kernel_api_spec *spec) {}
+static inline void kapi_check_locks(const struct kernel_api_spec *spec) {}
+static inline bool kapi_check_signal_allowed(const struct kernel_api_spec *spec, int signum)
+{
+ return true;
+}
+static inline bool kapi_validate_signal_action(const struct kernel_api_spec *spec, int signum,
+ struct sigaction *act)
+{
+ return true;
+}
+static inline int kapi_get_signal_error(const struct kernel_api_spec *spec, int signum)
+{
+ return -EINTR;
+}
+static inline bool kapi_is_signal_restartable(const struct kernel_api_spec *spec, int signum)
+{
+ return false;
+}
+#endif
+
+/* Export/query functions */
+const struct kernel_api_spec *kapi_get_spec(const char *name);
+int kapi_export_json(const struct kernel_api_spec *spec, char *buf, size_t size);
+void kapi_print_spec(const struct kernel_api_spec *spec);
+
+/* Registration for dynamic APIs */
+int kapi_register_spec(struct kernel_api_spec *spec);
+void kapi_unregister_spec(const char *name);
+
+/* Helper to get parameter constraint info */
+static inline bool kapi_get_param_constraint(const char *api_name, int param_idx,
+ enum kapi_constraint_type *type,
+ u64 *valid_mask, s64 *min_val, s64 *max_val)
+{
+ const struct kernel_api_spec *spec = kapi_get_spec(api_name);
+
+ if (!spec || param_idx >= spec->param_count)
+ return false;
+
+ if (type)
+ *type = spec->params[param_idx].constraint_type;
+ if (valid_mask)
+ *valid_mask = spec->params[param_idx].valid_mask;
+ if (min_val)
+ *min_val = spec->params[param_idx].min_value;
+ if (max_val)
+ *max_val = spec->params[param_idx].max_value;
+
+ return true;
+}
+
+#ifdef CONFIG_NET
+/* Networking-specific macros */
+
+/* Socket state requirement macros */
+#define KAPI_SOCKET_STATE_REQ(...) \
+ .socket_state = { \
+ .required_states = { __VA_ARGS__ }, \
+ .required_state_count = sizeof((enum kapi_socket_state[]){__VA_ARGS__})/sizeof(enum kapi_socket_state),
+
+#define KAPI_SOCKET_STATE_FORBID(...) \
+ .forbidden_states = { __VA_ARGS__ }, \
+ .forbidden_state_count = sizeof((enum kapi_socket_state[]){__VA_ARGS__})/sizeof(enum kapi_socket_state),
+
+#define KAPI_SOCKET_STATE_RESULT(state) \
+ .resulting_state = state,
+
+#define KAPI_SOCKET_STATE_COND(cond) \
+ .state_condition = cond,
+
+#define KAPI_SOCKET_STATE_PROTOS(protos) \
+ .applicable_protocols = protos,
+
+#define KAPI_SOCKET_STATE_END },
+
+/* Protocol behavior macros */
+#define KAPI_PROTOCOL_BEHAVIOR(idx, protos, desc) \
+ .protocol_behaviors[idx] = { \
+ .applicable_protocols = protos, \
+ .behavior = desc,
+
+#define KAPI_PROTOCOL_FLAGS(flags, desc) \
+ .protocol_flags = flags, \
+ .flag_description = desc,
+
+#define KAPI_PROTOCOL_BEHAVIOR_END },
+
+/* Async behavior macros */
+#define KAPI_ASYNC_SPEC(modes, errno) \
+ .async_spec = { \
+ .supported_modes = modes, \
+ .nonblock_errno = errno,
+
+#define KAPI_ASYNC_POLL(in, out) \
+ .poll_events_in = in, \
+ .poll_events_out = out,
+
+#define KAPI_ASYNC_COMPLETION(cond) \
+ .completion_condition = cond,
+
+#define KAPI_ASYNC_TIMEOUT(supported, desc) \
+ .supports_timeout = supported, \
+ .timeout_behavior = desc,
+
+#define KAPI_ASYNC_END },
+
+/* Buffer behavior macros */
+#define KAPI_BUFFER_SPEC(behaviors) \
+ .buffer_spec = { \
+ .buffer_behaviors = behaviors,
+
+#define KAPI_BUFFER_SIZE(min, max, optimal) \
+ .min_buffer_size = min, \
+ .max_buffer_size = max, \
+ .optimal_buffer_size = optimal,
+
+#define KAPI_BUFFER_PARTIAL(allowed, rules) \
+ .can_partial_transfer = allowed, \
+ .partial_transfer_rules = rules,
+
+#define KAPI_BUFFER_FRAGMENT(rules) \
+ .fragmentation_rules = rules,
+
+#define KAPI_BUFFER_END },
+
+/* Address family macros */
+#define KAPI_ADDR_FAMILY(idx, fam, name, struct_sz, min_len, max_len) \
+ .addr_families[idx] = { \
+ .family = fam, \
+ .family_name = name, \
+ .addr_struct_size = struct_sz, \
+ .min_addr_len = min_len, \
+ .max_addr_len = max_len,
+
+#define KAPI_ADDR_FORMAT(fmt) \
+ .addr_format = fmt,
+
+#define KAPI_ADDR_FEATURES(wildcard, multicast, broadcast) \
+ .supports_wildcard = wildcard, \
+ .supports_multicast = multicast, \
+ .supports_broadcast = broadcast,
+
+#define KAPI_ADDR_SPECIAL(addrs) \
+ .special_addresses = addrs,
+
+#define KAPI_ADDR_PORTS(min, max) \
+ .port_range_min = min, \
+ .port_range_max = max,
+
+#define KAPI_ADDR_FAMILY_END },
+
+#define KAPI_ADDR_FAMILY_COUNT(n) \
+ .addr_family_count = n,
+
+#define KAPI_PROTOCOL_BEHAVIOR_COUNT(n) \
+ .protocol_behavior_count = n,
+
+#define KAPI_CONSTRAINT_COUNT(n) \
+ .constraint_count = n,
+
+/* Network operation characteristics macros */
+#define KAPI_NET_CONNECTION_ORIENTED \
+ .is_connection_oriented = true,
+
+#define KAPI_NET_MESSAGE_ORIENTED \
+ .is_message_oriented = true,
+
+#define KAPI_NET_SUPPORTS_OOB \
+ .supports_oob_data = true,
+
+#define KAPI_NET_SUPPORTS_PEEK \
+ .supports_peek = true,
+
+#define KAPI_NET_REENTRANT \
+ .is_reentrant = true,
+
+/* Semantic description macros */
+#define KAPI_NET_CONN_ESTABLISH(desc) \
+ .connection_establishment = desc,
+
+#define KAPI_NET_CONN_TERMINATE(desc) \
+ .connection_termination = desc,
+
+#define KAPI_NET_DATA_TRANSFER(desc) \
+ .data_transfer_semantics = desc,
+
+#endif /* CONFIG_NET */
+
+#endif /* _LINUX_KERNEL_API_SPEC_H */
diff --git a/include/linux/syscall_api_spec.h b/include/linux/syscall_api_spec.h
new file mode 100644
index 0000000000000..0a813ad89ea15
--- /dev/null
+++ b/include/linux/syscall_api_spec.h
@@ -0,0 +1,137 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * syscall_api_spec.h - System Call API Specification Integration
+ *
+ * This header extends the SYSCALL_DEFINEX macros to support inline API specifications,
+ * allowing syscall documentation to be written alongside the implementation in a
+ * human-readable and machine-parseable format.
+ */
+
+#ifndef _LINUX_SYSCALL_API_SPEC_H
+#define _LINUX_SYSCALL_API_SPEC_H
+
+#include <linux/kernel_api_spec.h>
+
+
+
+/* Automatic syscall validation infrastructure */
+/*
+ * The validation is now integrated directly into the SYSCALL_DEFINEx macros
+ * in syscalls.h when CONFIG_KAPI_RUNTIME_CHECKS is enabled.
+ *
+ * The validation happens in the __do_kapi_sys##name wrapper function which:
+ * 1. Validates all parameters before calling the actual syscall
+ * 2. Calls the real syscall implementation
+ * 3. Validates the return value
+ * 4. Returns the result
+ */
+
+
+/*
+ * Helper macros for common syscall patterns
+ */
+
+/* For syscalls that can sleep */
+#define KAPI_SYSCALL_SLEEPABLE \
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE)
+
+/* For syscalls that must be atomic */
+#define KAPI_SYSCALL_ATOMIC \
+ KAPI_CONTEXT(KAPI_CTX_PROCESS | KAPI_CTX_ATOMIC)
+
+/* Common parameter specifications */
+#define KAPI_PARAM_FD(idx, desc) \
+ KAPI_PARAM(idx, "fd", "int", desc) \
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN) \
+ .type = KAPI_TYPE_FD, \
+ .constraint_type = KAPI_CONSTRAINT_NONE, \
+ KAPI_PARAM_END
+
+#define KAPI_PARAM_USER_BUF(idx, name, desc) \
+ KAPI_PARAM(idx, name, "void __user *", desc) \
+ KAPI_PARAM_FLAGS(KAPI_PARAM_USER_PTR | KAPI_PARAM_IN) \
+ KAPI_PARAM_END
+
+#define KAPI_PARAM_USER_STRUCT(idx, name, struct_type, desc) \
+ KAPI_PARAM(idx, name, #struct_type " __user *", desc) \
+ KAPI_PARAM_FLAGS(KAPI_PARAM_USER | KAPI_PARAM_IN) \
+ .type = KAPI_TYPE_USER_PTR, \
+ .size = sizeof(struct_type), \
+ .constraint_type = KAPI_CONSTRAINT_NONE, \
+ KAPI_PARAM_END
+
+#define KAPI_PARAM_SIZE_T(idx, name, desc) \
+ KAPI_PARAM(idx, name, "size_t", desc) \
+ KAPI_PARAM_FLAGS(KAPI_PARAM_IN) \
+ KAPI_PARAM_RANGE(0, SIZE_MAX) \
+ KAPI_PARAM_END
+
+/* Common error specifications */
+#define KAPI_ERROR_EBADF(idx) \
+ KAPI_ERROR(idx, -EBADF, "EBADF", "Invalid file descriptor", \
+ "The file descriptor is not valid or has been closed")
+
+#define KAPI_ERROR_EINVAL(idx, condition) \
+ KAPI_ERROR(idx, -EINVAL, "EINVAL", condition, \
+ "Invalid argument provided")
+
+#define KAPI_ERROR_ENOMEM(idx) \
+ KAPI_ERROR(idx, -ENOMEM, "ENOMEM", "Insufficient memory", \
+ "Cannot allocate memory for the operation")
+
+#define KAPI_ERROR_EPERM(idx) \
+ KAPI_ERROR(idx, -EPERM, "EPERM", "Operation not permitted", \
+ "The calling process does not have the required permissions")
+
+#define KAPI_ERROR_EFAULT(idx) \
+ KAPI_ERROR(idx, -EFAULT, "EFAULT", "Bad address", \
+ "Invalid user space address provided")
+
+/* Standard return value specifications */
+#define KAPI_RETURN_SUCCESS_ZERO \
+ KAPI_RETURN("long", "0 on success, negative error code on failure") \
+ KAPI_RETURN_SUCCESS(0, "== 0") \
+ KAPI_RETURN_END
+
+#define KAPI_RETURN_FD_SPEC \
+ KAPI_RETURN("long", "File descriptor on success, negative error code on failure") \
+ .check_type = KAPI_RETURN_FD, \
+ KAPI_RETURN_END
+
+#define KAPI_RETURN_COUNT \
+ KAPI_RETURN("long", "Number of bytes processed on success, negative error code on failure") \
+ KAPI_RETURN_SUCCESS(0, ">= 0") \
+ KAPI_RETURN_END
+
+/**
+ * KAPI_ERROR_COUNT - Set the error count
+ * @count: Number of errors defined
+ */
+#define KAPI_ERROR_COUNT(count) \
+ .error_count = count,
+
+/**
+ * KAPI_PARAM_COUNT - Set the parameter count
+ * @count: Number of parameters defined
+ */
+#define KAPI_PARAM_COUNT(count) \
+ .param_count = count,
+
+/**
+ * KAPI_SINCE_VERSION - Set the since version
+ * @version: Version string when the API was introduced
+ */
+#define KAPI_SINCE_VERSION(version) \
+ .since_version = version,
+
+
+/**
+ * KAPI_SIGNAL_MASK_COUNT - Set the signal mask count
+ * @count: Number of signal masks defined
+ */
+#define KAPI_SIGNAL_MASK_COUNT(count) \
+ .signal_mask_count = count,
+
+
+
+#endif /* _LINUX_SYSCALL_API_SPEC_H */
\ No newline at end of file
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e5603cc91963d..62a8edc14ec87 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -87,6 +87,7 @@ struct xattr_args;
#include <linux/bug.h>
#include <linux/sem.h>
#include <asm/siginfo.h>
+#include <linux/syscall_api_spec.h>
#include <linux/unistd.h>
#include <linux/quota.h>
#include <linux/key.h>
@@ -132,6 +133,7 @@ struct xattr_args;
#define __SC_TYPE(t, a) t
#define __SC_ARGS(t, a) a
#define __SC_TEST(t, a) (void)BUILD_BUG_ON_ZERO(!__TYPE_IS_LL(t) && sizeof(t) > sizeof(long))
+#define __SC_CAST_TO_S64(t, a) (s64)(a)
#ifdef CONFIG_FTRACE_SYSCALLS
#define __SC_STR_ADECL(t, a) #a
@@ -242,6 +244,41 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
* done within __do_sys_*().
*/
#ifndef __SYSCALL_DEFINEx
+#ifdef CONFIG_KAPI_RUNTIME_CHECKS
+#define __SYSCALL_DEFINEx(x, name, ...) \
+ __diag_push(); \
+ __diag_ignore(GCC, 8, "-Wattribute-alias", \
+ "Type aliasing is used to sanitize syscall arguments");\
+ asmlinkage long sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)) \
+ __attribute__((alias(__stringify(__se_sys##name)))); \
+ ALLOW_ERROR_INJECTION(sys##name, ERRNO); \
+ static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__));\
+ static inline long __do_kapi_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__)); \
+ asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)); \
+ asmlinkage long __se_sys##name(__MAP(x,__SC_LONG,__VA_ARGS__)) \
+ { \
+ long ret = __do_kapi_sys##name(__MAP(x,__SC_CAST,__VA_ARGS__));\
+ __MAP(x,__SC_TEST,__VA_ARGS__); \
+ __PROTECT(x, ret,__MAP(x,__SC_ARGS,__VA_ARGS__)); \
+ return ret; \
+ } \
+ __diag_pop(); \
+ static inline long __do_kapi_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))\
+ { \
+ const struct kernel_api_spec *__spec = kapi_get_spec("sys_" #name); \
+ if (__spec) { \
+ s64 __params[x] = { __MAP(x,__SC_CAST_TO_S64,__VA_ARGS__) }; \
+ int __ret = kapi_validate_syscall_params(__spec, __params, x); \
+ if (__ret) return __ret; \
+ } \
+ long ret = __do_sys##name(__MAP(x,__SC_ARGS,__VA_ARGS__)); \
+ if (__spec) { \
+ kapi_validate_syscall_return(__spec, (s64)ret); \
+ } \
+ return ret; \
+ } \
+ static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
+#else /* !CONFIG_KAPI_RUNTIME_CHECKS */
#define __SYSCALL_DEFINEx(x, name, ...) \
__diag_push(); \
__diag_ignore(GCC, 8, "-Wattribute-alias", \
@@ -260,6 +297,7 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
} \
__diag_pop(); \
static inline long __do_sys##name(__MAP(x,__SC_DECL,__VA_ARGS__))
+#endif /* CONFIG_KAPI_RUNTIME_CHECKS */
#endif /* __SYSCALL_DEFINEx */
/* For split 64-bit arguments on 32-bit architectures */
diff --git a/init/Kconfig b/init/Kconfig
index af4c2f0854554..7a15248933895 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -2079,6 +2079,8 @@ config TRACEPOINTS
source "kernel/Kconfig.kexec"
+source "kernel/api/Kconfig"
+
endmenu # General setup
source "arch/Kconfig"
diff --git a/kernel/Makefile b/kernel/Makefile
index 32e80dd626af0..ba94ee4bb2292 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -56,6 +56,7 @@ obj-y += livepatch/
obj-y += dma/
obj-y += entry/
obj-$(CONFIG_MODULES) += module/
+obj-$(CONFIG_KAPI_SPEC) += api/
obj-$(CONFIG_KCMP) += kcmp.o
obj-$(CONFIG_FREEZER) += freezer.o
diff --git a/kernel/api/Kconfig b/kernel/api/Kconfig
new file mode 100644
index 0000000000000..fde25ec70e134
--- /dev/null
+++ b/kernel/api/Kconfig
@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Kernel API Specification Framework Configuration
+#
+
+config KAPI_SPEC
+ bool "Kernel API Specification Framework"
+ help
+ This option enables the kernel API specification framework,
+ which provides formal documentation of kernel APIs in both
+ human and machine-readable formats.
+
+ The framework allows developers to document APIs inline with
+ their implementation, including parameter specifications,
+ return values, error conditions, locking requirements, and
+ execution context constraints.
+
+ When enabled, API specifications can be queried at runtime
+ and exported in various formats (JSON, XML) through debugfs.
+
+ If unsure, say N.
+
+config KAPI_RUNTIME_CHECKS
+ bool "Runtime API specification checks"
+ depends on KAPI_SPEC
+ depends on DEBUG_KERNEL
+ help
+ Enable runtime validation of API usage against specifications.
+ This includes checking execution context requirements, parameter
+ validation, and lock state verification.
+
+ This adds overhead and should only be used for debugging and
+ development. The checks use WARN_ONCE to report violations.
+
+ If unsure, say N.
diff --git a/kernel/api/Makefile b/kernel/api/Makefile
new file mode 100644
index 0000000000000..4120ded7e5cf1
--- /dev/null
+++ b/kernel/api/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the Kernel API Specification Framework
+#
+
+# Core API specification framework
+obj-$(CONFIG_KAPI_SPEC) += kernel_api_spec.o
\ No newline at end of file
diff --git a/kernel/api/kernel_api_spec.c b/kernel/api/kernel_api_spec.c
new file mode 100644
index 0000000000000..8827e9f96c111
--- /dev/null
+++ b/kernel/api/kernel_api_spec.c
@@ -0,0 +1,1122 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kernel_api_spec.c - Kernel API Specification Framework Implementation
+ *
+ * Provides runtime support for kernel API specifications including validation,
+ * export to various formats, and querying capabilities.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kernel_api_spec.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/export.h>
+#include <linux/preempt.h>
+#include <linux/hardirq.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/uaccess.h>
+#include <linux/limits.h>
+#include <linux/fcntl.h>
+
+/* Section where API specifications are stored */
+extern struct kernel_api_spec __start_kapi_specs[];
+extern struct kernel_api_spec __stop_kapi_specs[];
+
+/* Dynamic API registration */
+static LIST_HEAD(dynamic_api_specs);
+static DEFINE_MUTEX(api_spec_mutex);
+
+struct dynamic_api_spec {
+ struct list_head list;
+ struct kernel_api_spec *spec;
+};
+
+/**
+ * kapi_get_spec - Get API specification by name
+ * @name: Function name to look up
+ *
+ * Return: Pointer to API specification or NULL if not found
+ */
+const struct kernel_api_spec *kapi_get_spec(const char *name)
+{
+ struct kernel_api_spec *spec;
+ struct dynamic_api_spec *dyn_spec;
+
+ /* Search static specifications */
+ for (spec = __start_kapi_specs; spec < __stop_kapi_specs; spec++) {
+ if (strcmp(spec->name, name) == 0)
+ return spec;
+ }
+
+ /* Search dynamic specifications */
+ mutex_lock(&api_spec_mutex);
+ list_for_each_entry(dyn_spec, &dynamic_api_specs, list) {
+ if (strcmp(dyn_spec->spec->name, name) == 0) {
+ mutex_unlock(&api_spec_mutex);
+ return dyn_spec->spec;
+ }
+ }
+ mutex_unlock(&api_spec_mutex);
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(kapi_get_spec);
+
+/**
+ * kapi_register_spec - Register a dynamic API specification
+ * @spec: API specification to register
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+int kapi_register_spec(struct kernel_api_spec *spec)
+{
+ struct dynamic_api_spec *dyn_spec;
+
+ if (!spec || !spec->name[0])
+ return -EINVAL;
+
+ /* Check if already exists */
+ if (kapi_get_spec(spec->name))
+ return -EEXIST;
+
+ dyn_spec = kzalloc(sizeof(*dyn_spec), GFP_KERNEL);
+ if (!dyn_spec)
+ return -ENOMEM;
+
+ dyn_spec->spec = spec;
+
+ mutex_lock(&api_spec_mutex);
+ list_add_tail(&dyn_spec->list, &dynamic_api_specs);
+ mutex_unlock(&api_spec_mutex);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kapi_register_spec);
+
+/**
+ * kapi_unregister_spec - Unregister a dynamic API specification
+ * @name: Name of API to unregister
+ */
+void kapi_unregister_spec(const char *name)
+{
+ struct dynamic_api_spec *dyn_spec, *tmp;
+
+ mutex_lock(&api_spec_mutex);
+ list_for_each_entry_safe(dyn_spec, tmp, &dynamic_api_specs, list) {
+ if (strcmp(dyn_spec->spec->name, name) == 0) {
+ list_del(&dyn_spec->list);
+ kfree(dyn_spec);
+ break;
+ }
+ }
+ mutex_unlock(&api_spec_mutex);
+}
+EXPORT_SYMBOL_GPL(kapi_unregister_spec);
+
+/**
+ * param_type_to_string - Convert parameter type to string
+ * @type: Parameter type
+ *
+ * Return: String representation of type
+ */
+static const char *param_type_to_string(enum kapi_param_type type)
+{
+ static const char * const type_names[] = {
+ [KAPI_TYPE_VOID] = "void",
+ [KAPI_TYPE_INT] = "int",
+ [KAPI_TYPE_UINT] = "uint",
+ [KAPI_TYPE_PTR] = "pointer",
+ [KAPI_TYPE_STRUCT] = "struct",
+ [KAPI_TYPE_UNION] = "union",
+ [KAPI_TYPE_ENUM] = "enum",
+ [KAPI_TYPE_FUNC_PTR] = "function_pointer",
+ [KAPI_TYPE_ARRAY] = "array",
+ [KAPI_TYPE_FD] = "file_descriptor",
+ [KAPI_TYPE_USER_PTR] = "user_pointer",
+ [KAPI_TYPE_PATH] = "pathname",
+ [KAPI_TYPE_CUSTOM] = "custom",
+ };
+
+ if (type >= ARRAY_SIZE(type_names))
+ return "unknown";
+
+ return type_names[type];
+}
+
+/**
+ * lock_type_to_string - Convert lock type to string
+ * @type: Lock type
+ *
+ * Return: String representation of lock type
+ */
+static const char *lock_type_to_string(enum kapi_lock_type type)
+{
+ static const char * const lock_names[] = {
+ [KAPI_LOCK_NONE] = "none",
+ [KAPI_LOCK_MUTEX] = "mutex",
+ [KAPI_LOCK_SPINLOCK] = "spinlock",
+ [KAPI_LOCK_RWLOCK] = "rwlock",
+ [KAPI_LOCK_SEQLOCK] = "seqlock",
+ [KAPI_LOCK_RCU] = "rcu",
+ [KAPI_LOCK_SEMAPHORE] = "semaphore",
+ [KAPI_LOCK_CUSTOM] = "custom",
+ };
+
+ if (type >= ARRAY_SIZE(lock_names))
+ return "unknown";
+
+ return lock_names[type];
+}
+
+/**
+ * return_check_type_to_string - Convert return check type to string
+ * @type: Return check type
+ *
+ * Return: String representation of return check type
+ */
+static const char *return_check_type_to_string(enum kapi_return_check_type type)
+{
+ static const char * const check_names[] = {
+ [KAPI_RETURN_EXACT] = "exact",
+ [KAPI_RETURN_RANGE] = "range",
+ [KAPI_RETURN_ERROR_CHECK] = "error_check",
+ [KAPI_RETURN_FD] = "file_descriptor",
+ [KAPI_RETURN_CUSTOM] = "custom",
+ };
+
+ if (type >= ARRAY_SIZE(check_names))
+ return "unknown";
+
+ return check_names[type];
+}
+
+/**
+ * capability_action_to_string - Convert capability action to string
+ * @action: Capability action
+ *
+ * Return: String representation of capability action
+ */
+static const char *capability_action_to_string(enum kapi_capability_action action)
+{
+ static const char * const action_names[] = {
+ [KAPI_CAP_BYPASS_CHECK] = "bypass_check",
+ [KAPI_CAP_INCREASE_LIMIT] = "increase_limit",
+ [KAPI_CAP_OVERRIDE_RESTRICTION] = "override_restriction",
+ [KAPI_CAP_GRANT_PERMISSION] = "grant_permission",
+ [KAPI_CAP_MODIFY_BEHAVIOR] = "modify_behavior",
+ [KAPI_CAP_ACCESS_RESOURCE] = "access_resource",
+ [KAPI_CAP_PERFORM_OPERATION] = "perform_operation",
+ };
+
+ if (action >= ARRAY_SIZE(action_names))
+ return "unknown";
+
+ return action_names[action];
+}
+
+/**
+ * kapi_export_json - Export API specification to JSON format
+ * @spec: API specification to export
+ * @buf: Buffer to write JSON to
+ * @size: Size of buffer
+ *
+ * Return: Number of bytes written or negative error
+ */
+int kapi_export_json(const struct kernel_api_spec *spec, char *buf, size_t size)
+{
+ int ret = 0;
+ int i;
+
+ if (!spec || !buf || size == 0)
+ return -EINVAL;
+
+ ret = scnprintf(buf, size,
+ "{\n"
+ " \"name\": \"%s\",\n"
+ " \"version\": %u,\n"
+ " \"description\": \"%s\",\n"
+ " \"long_description\": \"%s\",\n"
+ " \"context_flags\": \"0x%x\",\n",
+ spec->name,
+ spec->version,
+ spec->description,
+ spec->long_description,
+ spec->context_flags);
+
+ /* Parameters */
+ ret += scnprintf(buf + ret, size - ret,
+ " \"parameters\": [\n");
+
+ for (i = 0; i < spec->param_count && i < KAPI_MAX_PARAMS; i++) {
+ const struct kapi_param_spec *param = &spec->params[i];
+
+ ret += scnprintf(buf + ret, size - ret,
+ " {\n"
+ " \"name\": \"%s\",\n"
+ " \"type\": \"%s\",\n"
+ " \"type_class\": \"%s\",\n"
+ " \"flags\": \"0x%x\",\n"
+ " \"description\": \"%s\"\n"
+ " }%s\n",
+ param->name,
+ param->type_name,
+ param_type_to_string(param->type),
+ param->flags,
+ param->description,
+ (i < spec->param_count - 1) ? "," : "");
+ }
+
+ ret += scnprintf(buf + ret, size - ret, " ],\n");
+
+ /* Return value */
+ ret += scnprintf(buf + ret, size - ret,
+ " \"return\": {\n"
+ " \"type\": \"%s\",\n"
+ " \"type_class\": \"%s\",\n"
+ " \"check_type\": \"%s\",\n",
+ spec->return_spec.type_name,
+ param_type_to_string(spec->return_spec.type),
+ return_check_type_to_string(spec->return_spec.check_type));
+
+ switch (spec->return_spec.check_type) {
+ case KAPI_RETURN_EXACT:
+ ret += scnprintf(buf + ret, size - ret,
+ " \"success_value\": %lld,\n",
+ spec->return_spec.success_value);
+ break;
+ case KAPI_RETURN_RANGE:
+ ret += scnprintf(buf + ret, size - ret,
+ " \"success_min\": %lld,\n"
+ " \"success_max\": %lld,\n",
+ spec->return_spec.success_min,
+ spec->return_spec.success_max);
+ break;
+ case KAPI_RETURN_ERROR_CHECK:
+ ret += scnprintf(buf + ret, size - ret,
+ " \"error_count\": %u,\n",
+ spec->return_spec.error_count);
+ break;
+ default:
+ break;
+ }
+
+ ret += scnprintf(buf + ret, size - ret,
+ " \"description\": \"%s\"\n"
+ " },\n",
+ spec->return_spec.description);
+
+ /* Errors */
+ ret += scnprintf(buf + ret, size - ret,
+ " \"errors\": [\n");
+
+ for (i = 0; i < spec->error_count && i < KAPI_MAX_ERRORS; i++) {
+ const struct kapi_error_spec *error = &spec->errors[i];
+
+ ret += scnprintf(buf + ret, size - ret,
+ " {\n"
+ " \"code\": %d,\n"
+ " \"name\": \"%s\",\n"
+ " \"condition\": \"%s\",\n"
+ " \"description\": \"%s\"\n"
+ " }%s\n",
+ error->error_code,
+ error->name,
+ error->condition,
+ error->description,
+ (i < spec->error_count - 1) ? "," : "");
+ }
+
+ ret += scnprintf(buf + ret, size - ret, " ],\n");
+
+ /* Locks */
+ ret += scnprintf(buf + ret, size - ret,
+ " \"locks\": [\n");
+
+ for (i = 0; i < spec->lock_count && i < KAPI_MAX_CONSTRAINTS; i++) {
+ const struct kapi_lock_spec *lock = &spec->locks[i];
+
+ ret += scnprintf(buf + ret, size - ret,
+ " {\n"
+ " \"name\": \"%s\",\n"
+ " \"type\": \"%s\",\n"
+ " \"acquired\": %s,\n"
+ " \"released\": %s,\n"
+ " \"held_on_entry\": %s,\n"
+ " \"held_on_exit\": %s,\n"
+ " \"description\": \"%s\"\n"
+ " }%s\n",
+ lock->lock_name,
+ lock_type_to_string(lock->lock_type),
+ lock->acquired ? "true" : "false",
+ lock->released ? "true" : "false",
+ lock->held_on_entry ? "true" : "false",
+ lock->held_on_exit ? "true" : "false",
+ lock->description,
+ (i < spec->lock_count - 1) ? "," : "");
+ }
+
+ ret += scnprintf(buf + ret, size - ret, " ],\n");
+
+ /* Capabilities */
+ ret += scnprintf(buf + ret, size - ret,
+ " \"capabilities\": [\n");
+
+ for (i = 0; i < spec->capability_count && i < KAPI_MAX_CAPABILITIES; i++) {
+ const struct kapi_capability_spec *cap = &spec->capabilities[i];
+
+ ret += scnprintf(buf + ret, size - ret,
+ " {\n"
+ " \"capability\": %d,\n"
+ " \"name\": \"%s\",\n"
+ " \"action\": \"%s\",\n"
+ " \"allows\": \"%s\",\n"
+ " \"without_cap\": \"%s\",\n"
+ " \"check_condition\": \"%s\",\n"
+ " \"priority\": %u",
+ cap->capability,
+ cap->cap_name,
+ capability_action_to_string(cap->action),
+ cap->allows,
+ cap->without_cap,
+ cap->check_condition,
+ cap->priority);
+
+ if (cap->alternative_count > 0) {
+ int j;
+ ret += scnprintf(buf + ret, size - ret,
+ ",\n \"alternatives\": [");
+ for (j = 0; j < cap->alternative_count; j++) {
+ ret += scnprintf(buf + ret, size - ret,
+ "%d%s", cap->alternative[j],
+ (j < cap->alternative_count - 1) ? ", " : "");
+ }
+ ret += scnprintf(buf + ret, size - ret, "]");
+ }
+
+ ret += scnprintf(buf + ret, size - ret,
+ "\n }%s\n",
+ (i < spec->capability_count - 1) ? "," : "");
+ }
+
+ ret += scnprintf(buf + ret, size - ret, " ],\n");
+
+ /* Additional info */
+ ret += scnprintf(buf + ret, size - ret,
+ " \"since_version\": \"%s\",\n"
+ " \"deprecated\": %s,\n"
+ " \"replacement\": \"%s\",\n"
+ " \"examples\": \"%s\",\n"
+ " \"notes\": \"%s\"\n"
+ "}\n",
+ spec->since_version,
+ spec->deprecated ? "true" : "false",
+ spec->replacement,
+ spec->examples,
+ spec->notes);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kapi_export_json);
+
+
+/**
+ * kapi_print_spec - Print API specification to kernel log
+ * @spec: API specification to print
+ */
+void kapi_print_spec(const struct kernel_api_spec *spec)
+{
+ int i;
+
+ if (!spec)
+ return;
+
+ pr_info("=== Kernel API Specification ===\n");
+ pr_info("Name: %s\n", spec->name);
+ pr_info("Version: %u\n", spec->version);
+ pr_info("Description: %s\n", spec->description);
+
+ if (spec->long_description[0])
+ pr_info("Long Description: %s\n", spec->long_description);
+
+ pr_info("Context Flags: 0x%x\n", spec->context_flags);
+
+ /* Parameters */
+ if (spec->param_count > 0) {
+ pr_info("Parameters:\n");
+ for (i = 0; i < spec->param_count && i < KAPI_MAX_PARAMS; i++) {
+ const struct kapi_param_spec *param = &spec->params[i];
+ pr_info(" [%d] %s: %s (flags: 0x%x)\n",
+ i, param->name, param->type_name, param->flags);
+ if (param->description[0])
+ pr_info(" Description: %s\n", param->description);
+ }
+ }
+
+ /* Return value */
+ pr_info("Return: %s\n", spec->return_spec.type_name);
+ if (spec->return_spec.description[0])
+ pr_info(" Description: %s\n", spec->return_spec.description);
+
+ /* Errors */
+ if (spec->error_count > 0) {
+ pr_info("Possible Errors:\n");
+ for (i = 0; i < spec->error_count && i < KAPI_MAX_ERRORS; i++) {
+ const struct kapi_error_spec *error = &spec->errors[i];
+ pr_info(" %s (%d): %s\n",
+ error->name, error->error_code, error->condition);
+ }
+ }
+
+ /* Capabilities */
+ if (spec->capability_count > 0) {
+ pr_info("Capabilities:\n");
+ for (i = 0; i < spec->capability_count && i < KAPI_MAX_CAPABILITIES; i++) {
+ const struct kapi_capability_spec *cap = &spec->capabilities[i];
+ pr_info(" %s (%d):\n", cap->cap_name, cap->capability);
+ pr_info(" Action: %s\n", capability_action_to_string(cap->action));
+ pr_info(" Allows: %s\n", cap->allows);
+ pr_info(" Without: %s\n", cap->without_cap);
+ if (cap->check_condition[0])
+ pr_info(" Condition: %s\n", cap->check_condition);
+ }
+ }
+
+ pr_info("================================\n");
+}
+EXPORT_SYMBOL_GPL(kapi_print_spec);
+
+#ifdef CONFIG_KAPI_RUNTIME_CHECKS
+
+/**
+ * kapi_validate_fd - Validate that a file descriptor is valid in current context
+ * @fd: File descriptor to validate
+ *
+ * Return: true if fd is valid in current process context, false otherwise
+ */
+static bool kapi_validate_fd(int fd)
+{
+ struct fd f;
+
+ /* Special case: AT_FDCWD is always valid */
+ if (fd == AT_FDCWD)
+ return true;
+
+ /* Check basic range */
+ if (fd < 0)
+ return false;
+
+ /* Check if fd is valid in current process context */
+ f = fdget(fd);
+ if (fd_empty(f)) {
+ return false;
+ }
+
+ /* fd is valid, release reference */
+ fdput(f);
+ return true;
+}
+
+/**
+ * kapi_validate_user_ptr - Validate that a user pointer is accessible
+ * @ptr: User pointer to validate
+ * @size: Size in bytes to validate
+ * @write: Whether write access is required
+ *
+ * Return: true if user memory is accessible, false otherwise
+ */
+static bool kapi_validate_user_ptr(const void __user *ptr, size_t size, bool write)
+{
+ /* NULL is valid if parameter is marked optional */
+ if (!ptr)
+ return false;
+
+ /* Check if the user memory region is accessible */
+ if (write) {
+ return access_ok(ptr, size);
+ } else {
+ return access_ok(ptr, size);
+ }
+}
+
+/**
+ * kapi_validate_user_ptr_with_params - Validate user pointer with dynamic size
+ * @param_spec: Parameter specification
+ * @ptr: User pointer to validate
+ * @all_params: Array of all parameter values
+ * @param_count: Number of parameters
+ *
+ * Return: true if user memory is accessible, false otherwise
+ */
+static bool kapi_validate_user_ptr_with_params(const struct kapi_param_spec *param_spec,
+ const void __user *ptr,
+ const s64 *all_params,
+ int param_count)
+{
+ size_t actual_size;
+ bool write;
+
+ /* NULL is allowed for optional parameters */
+ if (!ptr && (param_spec->flags & KAPI_PARAM_OPTIONAL))
+ return true;
+
+ /* Calculate actual size based on related parameter */
+ if (param_spec->size_param_idx >= 0 &&
+ param_spec->size_param_idx < param_count) {
+ s64 count = all_params[param_spec->size_param_idx];
+
+ /* Validate count is positive */
+ if (count <= 0) {
+ pr_warn("Parameter %s: size determinant is non-positive (%lld)\n",
+ param_spec->name, count);
+ return false;
+ }
+
+ /* Check for multiplication overflow */
+ if (param_spec->size_multiplier > 0 &&
+ count > SIZE_MAX / param_spec->size_multiplier) {
+ pr_warn("Parameter %s: size calculation overflow\n",
+ param_spec->name);
+ return false;
+ }
+
+ actual_size = count * param_spec->size_multiplier;
+ } else {
+ /* Use fixed size */
+ actual_size = param_spec->size;
+ }
+
+ write = (param_spec->flags & KAPI_PARAM_OUT) ||
+ (param_spec->flags & KAPI_PARAM_INOUT);
+
+ return kapi_validate_user_ptr(ptr, actual_size, write);
+}
+
+/**
+ * kapi_validate_path - Validate that a pathname is accessible and within limits
+ * @path: User pointer to pathname
+ * @param_spec: Parameter specification
+ *
+ * Return: true if path is valid, false otherwise
+ */
+static bool kapi_validate_path(const char __user *path,
+ const struct kapi_param_spec *param_spec)
+{
+ size_t len;
+
+ /* NULL is allowed for optional parameters */
+ if (!path && (param_spec->flags & KAPI_PARAM_OPTIONAL))
+ return true;
+
+ if (!path) {
+ pr_warn("Parameter %s: NULL path not allowed\n", param_spec->name);
+ return false;
+ }
+
+ /* Check if the path is accessible */
+ if (!access_ok(path, 1)) {
+ pr_warn("Parameter %s: path pointer %p not accessible\n",
+ param_spec->name, path);
+ return false;
+ }
+
+ /* Use strnlen_user to get the length and validate accessibility */
+ len = strnlen_user(path, PATH_MAX + 1);
+ if (len == 0) {
+ pr_warn("Parameter %s: invalid path pointer %p\n",
+ param_spec->name, path);
+ return false;
+ }
+
+ /* Check path length limit */
+ if (len > PATH_MAX) {
+ pr_warn("Parameter %s: path too long (exceeds PATH_MAX)\n",
+ param_spec->name);
+ return false;
+ }
+
+ return true;
+}
+
+/**
+ * kapi_validate_param - Validate a parameter against its specification
+ * @param_spec: Parameter specification
+ * @value: Parameter value to validate
+ *
+ * Return: true if valid, false otherwise
+ */
+bool kapi_validate_param(const struct kapi_param_spec *param_spec, s64 value)
+{
+ int i;
+
+ /* Special handling for file descriptor type */
+ if (param_spec->type == KAPI_TYPE_FD) {
+ if (!kapi_validate_fd((int)value)) {
+ pr_warn("Parameter %s: invalid file descriptor %lld\n",
+ param_spec->name, value);
+ return false;
+ }
+ /* Continue with additional constraint checks if needed */
+ }
+
+ /* Special handling for user pointer type */
+ if (param_spec->type == KAPI_TYPE_USER_PTR) {
+ const void __user *ptr = (const void __user *)value;
+ bool write = (param_spec->flags & KAPI_PARAM_OUT) ||
+ (param_spec->flags & KAPI_PARAM_INOUT);
+
+ /* NULL is allowed for optional parameters */
+ if (!ptr && (param_spec->flags & KAPI_PARAM_OPTIONAL))
+ return true;
+
+ if (!kapi_validate_user_ptr(ptr, param_spec->size, write)) {
+ pr_warn("Parameter %s: invalid user pointer %p (size: %zu, %s)\n",
+ param_spec->name, ptr, param_spec->size,
+ write ? "write" : "read");
+ return false;
+ }
+ /* Continue with additional constraint checks if needed */
+ }
+
+ /* Special handling for path type */
+ if (param_spec->type == KAPI_TYPE_PATH) {
+ const char __user *path = (const char __user *)value;
+
+ if (!kapi_validate_path(path, param_spec)) {
+ return false;
+ }
+ /* Continue with additional constraint checks if needed */
+ }
+
+ switch (param_spec->constraint_type) {
+ case KAPI_CONSTRAINT_NONE:
+ return true;
+
+ case KAPI_CONSTRAINT_RANGE:
+ if (value < param_spec->min_value || value > param_spec->max_value) {
+ pr_warn("Parameter %s value %lld out of range [%lld, %lld]\n",
+ param_spec->name, value,
+ param_spec->min_value, param_spec->max_value);
+ return false;
+ }
+ return true;
+
+ case KAPI_CONSTRAINT_MASK:
+ if (value & ~param_spec->valid_mask) {
+ pr_warn("Parameter %s value 0x%llx contains invalid bits (valid mask: 0x%llx)\n",
+ param_spec->name, value, param_spec->valid_mask);
+ return false;
+ }
+ return true;
+
+ case KAPI_CONSTRAINT_ENUM:
+ if (!param_spec->enum_values || param_spec->enum_count == 0)
+ return true;
+
+ for (i = 0; i < param_spec->enum_count; i++) {
+ if (value == param_spec->enum_values[i])
+ return true;
+ }
+ pr_warn("Parameter %s value %lld not in valid enumeration\n",
+ param_spec->name, value);
+ return false;
+
+ case KAPI_CONSTRAINT_CUSTOM:
+ if (param_spec->validate)
+ return param_spec->validate(value);
+ return true;
+
+ default:
+ return true;
+ }
+}
+EXPORT_SYMBOL_GPL(kapi_validate_param);
+
+/**
+ * kapi_validate_param_with_context - Validate parameter with access to all params
+ * @param_spec: Parameter specification
+ * @value: Parameter value to validate
+ * @all_params: Array of all parameter values
+ * @param_count: Number of parameters
+ *
+ * Return: true if valid, false otherwise
+ */
+bool kapi_validate_param_with_context(const struct kapi_param_spec *param_spec,
+ s64 value, const s64 *all_params, int param_count)
+{
+ /* Special handling for user pointer type with dynamic sizing */
+ if (param_spec->type == KAPI_TYPE_USER_PTR) {
+ const void __user *ptr = (const void __user *)value;
+
+ /* NULL is allowed for optional parameters */
+ if (!ptr && (param_spec->flags & KAPI_PARAM_OPTIONAL))
+ return true;
+
+ if (!kapi_validate_user_ptr_with_params(param_spec, ptr, all_params, param_count)) {
+ pr_warn("Parameter %s: invalid user pointer %p\n",
+ param_spec->name, ptr);
+ return false;
+ }
+ /* Continue with additional constraint checks if needed */
+ }
+
+ /* For other types, fall back to regular validation */
+ return kapi_validate_param(param_spec, value);
+}
+EXPORT_SYMBOL_GPL(kapi_validate_param_with_context);
+
+/**
+ * kapi_validate_syscall_param - Validate syscall parameter with enforcement
+ * @spec: API specification
+ * @param_idx: Parameter index
+ * @value: Parameter value
+ *
+ * Return: -EINVAL if invalid, 0 if valid
+ */
+int kapi_validate_syscall_param(const struct kernel_api_spec *spec,
+ int param_idx, s64 value)
+{
+ const struct kapi_param_spec *param_spec;
+
+ if (!spec || param_idx >= spec->param_count)
+ return 0;
+
+ param_spec = &spec->params[param_idx];
+
+ if (!kapi_validate_param(param_spec, value)) {
+ if (strncmp(spec->name, "sys_", 4) == 0) {
+ /* For syscalls, we can return EINVAL to userspace */
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kapi_validate_syscall_param);
+
+/**
+ * kapi_validate_syscall_params - Validate all syscall parameters together
+ * @spec: API specification
+ * @params: Array of parameter values
+ * @param_count: Number of parameters
+ *
+ * Return: -EINVAL if any parameter is invalid, 0 if all valid
+ */
+int kapi_validate_syscall_params(const struct kernel_api_spec *spec,
+ const s64 *params, int param_count)
+{
+ int i;
+
+ if (!spec || !params)
+ return 0;
+
+ /* Validate that we have the expected number of parameters */
+ if (param_count != spec->param_count) {
+ pr_warn("API %s: parameter count mismatch (expected %u, got %d)\n",
+ spec->name, spec->param_count, param_count);
+ return -EINVAL;
+ }
+
+ /* Validate each parameter with context */
+ for (i = 0; i < spec->param_count && i < KAPI_MAX_PARAMS; i++) {
+ const struct kapi_param_spec *param_spec = &spec->params[i];
+
+ if (!kapi_validate_param_with_context(param_spec, params[i], params, param_count)) {
+ if (strncmp(spec->name, "sys_", 4) == 0) {
+ /* For syscalls, we can return EINVAL to userspace */
+ return -EINVAL;
+ }
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kapi_validate_syscall_params);
+
+/**
+ * kapi_check_return_success - Check if return value indicates success
+ * @return_spec: Return specification
+ * @retval: Return value to check
+ *
+ * Returns true if the return value indicates success according to the spec.
+ */
+bool kapi_check_return_success(const struct kapi_return_spec *return_spec, s64 retval)
+{
+ u32 i;
+
+ if (!return_spec)
+ return true; /* No spec means we can't validate */
+
+ switch (return_spec->check_type) {
+ case KAPI_RETURN_EXACT:
+ return retval == return_spec->success_value;
+
+ case KAPI_RETURN_RANGE:
+ return retval >= return_spec->success_min &&
+ retval <= return_spec->success_max;
+
+ case KAPI_RETURN_ERROR_CHECK:
+ /* Success if NOT in error list */
+ if (return_spec->error_values) {
+ for (i = 0; i < return_spec->error_count; i++) {
+ if (retval == return_spec->error_values[i])
+ return false; /* Found in error list */
+ }
+ }
+ return true; /* Not in error list = success */
+
+ case KAPI_RETURN_FD:
+ /* File descriptors: >= 0 is success, < 0 is error */
+ return retval >= 0;
+
+ case KAPI_RETURN_CUSTOM:
+ if (return_spec->is_success)
+ return return_spec->is_success(retval);
+ fallthrough;
+
+ default:
+ return true; /* Unknown check type, assume success */
+ }
+}
+EXPORT_SYMBOL_GPL(kapi_check_return_success);
+
+/**
+ * kapi_validate_return_value - Validate that return value matches spec
+ * @spec: API specification
+ * @retval: Return value to validate
+ *
+ * Return: true if return value is valid according to spec, false otherwise.
+ *
+ * This function checks:
+ * 1. If the value indicates success, it must match the success criteria
+ * 2. If the value indicates error, it must be one of the specified error codes
+ */
+bool kapi_validate_return_value(const struct kernel_api_spec *spec, s64 retval)
+{
+ int i;
+ bool is_success;
+
+ if (!spec)
+ return true; /* No spec means we can't validate */
+
+ /* First check if this is a success return */
+ is_success = kapi_check_return_success(&spec->return_spec, retval);
+
+ if (is_success) {
+ /* Success case - already validated by kapi_check_return_success */
+ return true;
+ }
+
+ /* Special validation for file descriptor returns */
+ if (spec->return_spec.check_type == KAPI_RETURN_FD && is_success) {
+ /* For successful FD returns, validate it's a valid FD */
+ if (!kapi_validate_fd((int)retval)) {
+ pr_warn("API %s returned invalid file descriptor %lld\n",
+ spec->name, retval);
+ return false;
+ }
+ return true;
+ }
+
+ /* Error case - check if it's one of the specified errors */
+ if (spec->error_count == 0) {
+ /* No errors specified, so any error is potentially valid */
+ pr_debug("API %s returned unspecified error %lld\n",
+ spec->name, retval);
+ return true;
+ }
+
+ /* Check if the error is in our list of specified errors */
+ for (i = 0; i < spec->error_count && i < KAPI_MAX_ERRORS; i++) {
+ if (retval == spec->errors[i].error_code)
+ return true;
+ }
+
+ /* Error not in spec */
+ pr_warn("API %s returned unspecified error code %lld. Valid errors are:\n",
+ spec->name, retval);
+ for (i = 0; i < spec->error_count && i < KAPI_MAX_ERRORS; i++) {
+ pr_warn(" %s (%d): %s\n",
+ spec->errors[i].name,
+ spec->errors[i].error_code,
+ spec->errors[i].condition);
+ }
+
+ return false;
+}
+EXPORT_SYMBOL_GPL(kapi_validate_return_value);
+
+/**
+ * kapi_validate_syscall_return - Validate syscall return value with enforcement
+ * @spec: API specification
+ * @retval: Return value
+ *
+ * Return: 0 if valid, -EINVAL if the return value doesn't match spec
+ *
+ * For syscalls, this can help detect kernel bugs where unspecified error
+ * codes are returned to userspace.
+ */
+int kapi_validate_syscall_return(const struct kernel_api_spec *spec, s64 retval)
+{
+ if (!spec)
+ return 0;
+
+ if (!kapi_validate_return_value(spec, retval)) {
+ /* Log the violation but don't change the return value */
+ WARN_ONCE(1, "Syscall %s returned unspecified value %lld\n",
+ spec->name, retval);
+ /* Could return -EINVAL here to enforce, but that might break userspace */
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kapi_validate_syscall_return);
+
+/**
+ * kapi_check_context - Check if current context matches API requirements
+ * @spec: API specification to check against
+ */
+void kapi_check_context(const struct kernel_api_spec *spec)
+{
+ u32 ctx = spec->context_flags;
+ bool valid = false;
+
+ if (!ctx)
+ return;
+
+ /* Check if we're in an allowed context */
+ if ((ctx & KAPI_CTX_PROCESS) && !in_interrupt())
+ valid = true;
+
+ if ((ctx & KAPI_CTX_SOFTIRQ) && in_softirq())
+ valid = true;
+
+ if ((ctx & KAPI_CTX_HARDIRQ) && in_hardirq())
+ valid = true;
+
+ if ((ctx & KAPI_CTX_NMI) && in_nmi())
+ valid = true;
+
+ if (!valid) {
+ WARN_ONCE(1, "API %s called from invalid context\n", spec->name);
+ }
+
+ /* Check specific requirements */
+ if ((ctx & KAPI_CTX_ATOMIC) && preemptible()) {
+ WARN_ONCE(1, "API %s requires atomic context\n", spec->name);
+ }
+
+ if ((ctx & KAPI_CTX_SLEEPABLE) && !preemptible()) {
+ WARN_ONCE(1, "API %s requires sleepable context\n", spec->name);
+ }
+}
+EXPORT_SYMBOL_GPL(kapi_check_context);
+
+#endif /* CONFIG_KAPI_RUNTIME_CHECKS */
+
+/* DebugFS interface */
+#ifdef CONFIG_DEBUG_FS
+
+static struct dentry *kapi_debugfs_root;
+
+static int kapi_spec_show(struct seq_file *s, void *v)
+{
+ struct kernel_api_spec *spec = s->private;
+ char *buf;
+ int ret;
+
+ buf = kmalloc(PAGE_SIZE * 4, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ ret = kapi_export_json(spec, buf, PAGE_SIZE * 4);
+ if (ret > 0)
+ seq_printf(s, "%s", buf);
+
+ kfree(buf);
+ return 0;
+}
+
+static int kapi_spec_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, kapi_spec_show, inode->i_private);
+}
+
+static const struct file_operations kapi_spec_fops = {
+ .open = kapi_spec_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static int kapi_list_show(struct seq_file *s, void *v)
+{
+ struct kernel_api_spec *spec;
+ struct dynamic_api_spec *dyn_spec;
+
+ seq_printf(s, "Kernel API Specifications:\n\n");
+
+ /* List static specifications */
+ seq_printf(s, "Static APIs:\n");
+ for (spec = __start_kapi_specs; spec < __stop_kapi_specs; spec++) {
+ seq_printf(s, " %s (v%u): %s\n",
+ spec->name, spec->version, spec->description);
+ }
+
+ /* List dynamic specifications */
+ seq_printf(s, "\nDynamic APIs:\n");
+ mutex_lock(&api_spec_mutex);
+ list_for_each_entry(dyn_spec, &dynamic_api_specs, list) {
+ spec = dyn_spec->spec;
+ seq_printf(s, " %s (v%u): %s\n",
+ spec->name, spec->version, spec->description);
+ }
+ mutex_unlock(&api_spec_mutex);
+
+ return 0;
+}
+
+static int kapi_list_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, kapi_list_show, NULL);
+}
+
+static const struct file_operations kapi_list_fops = {
+ .open = kapi_list_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+static int __init kapi_debugfs_init(void)
+{
+ struct kernel_api_spec *spec;
+ struct dentry *spec_dir;
+
+ kapi_debugfs_root = debugfs_create_dir("kapi", NULL);
+ if (!kapi_debugfs_root)
+ return -ENOMEM;
+
+ /* Create list file */
+ debugfs_create_file("list", 0444, kapi_debugfs_root, NULL,
+ &kapi_list_fops);
+
+ /* Create directory for specifications */
+ spec_dir = debugfs_create_dir("specs", kapi_debugfs_root);
+
+ /* Create files for each static specification */
+ for (spec = __start_kapi_specs; spec < __stop_kapi_specs; spec++) {
+ debugfs_create_file(spec->name, 0444, spec_dir, spec,
+ &kapi_spec_fops);
+ }
+
+ return 0;
+}
+
+late_initcall(kapi_debugfs_init);
+
+#endif /* CONFIG_DEBUG_FS */
\ No newline at end of file
--
2.39.5
Sasha Levin <sashal@kernel.org> writes: > Add a comprehensive framework for formally documenting kernel APIs with > inline specifications. This framework provides: > > - Structured API documentation with parameter specifications, return > values, error conditions, and execution context requirements > - Runtime validation capabilities for debugging (CONFIG_KAPI_RUNTIME_CHECKS) > - Export of specifications via debugfs for tooling integration > - Support for both internal kernel APIs and system calls > > The framework stores specifications in a dedicated ELF section and > provides infrastructure for: > - Compile-time validation of specifications > - Runtime querying of API documentation > - Machine-readable export formats > - Integration with existing SYSCALL_DEFINE macros > > This commit introduces the core infrastructure without modifying any > existing APIs. Subsequent patches will add specifications to individual > subsystems. > > Signed-off-by: Sasha Levin <sashal@kernel.org> > --- > Documentation/admin-guide/kernel-api-spec.rst | 507 ++++++ You need to add that file to index.rst in that directory or it won't be pulled into the docs build. Wouldn't it be nice to integrate all this stuff with out existing kerneldoc mechanism...? :) Thanks, jon
Em Mon, 30 Jun 2025 13:53:55 -0600 Jonathan Corbet <corbet@lwn.net> escreveu: > Sasha Levin <sashal@kernel.org> writes: > > > Add a comprehensive framework for formally documenting kernel APIs with > > inline specifications. This framework provides: > > > > - Structured API documentation with parameter specifications, return > > values, error conditions, and execution context requirements > > - Runtime validation capabilities for debugging (CONFIG_KAPI_RUNTIME_CHECKS) > > - Export of specifications via debugfs for tooling integration > > - Support for both internal kernel APIs and system calls > > > > The framework stores specifications in a dedicated ELF section and > > provides infrastructure for: > > - Compile-time validation of specifications > > - Runtime querying of API documentation > > - Machine-readable export formats > > - Integration with existing SYSCALL_DEFINE macros > > > > This commit introduces the core infrastructure without modifying any > > existing APIs. Subsequent patches will add specifications to individual > > subsystems. > > > > Signed-off-by: Sasha Levin <sashal@kernel.org> > > --- > > Documentation/admin-guide/kernel-api-spec.rst | 507 ++++++ > > You need to add that file to index.rst in that directory or it won't be > pulled into the docs build. > > Wouldn't it be nice to integrate all this stuff with out existing > kerneldoc mechanism...? :) +1 Having two different mechanisms (kapi and kerneldoc) makes a lot harder to maintain kAPI. Also, IGT (a testing tool for DRM subsystem) used to have a macro based documentation system. It got outdated with time, as people ends forgetting to update the macros when changing the code. Also, sometimes we want to add some rich text there, with graphs, tables, ... More important than that: people end not remembering to add such macros. As kerneldoc markups are similar to Doxygen and normal C comments, it is more likely that people will remember. So, IMO the best would be to use kerneldoc syntax there, letting Kerneldoc Sphinx extension handling it for docs, while having tools to implement the other features you mentioned. Thanks, Mauro
On Tue, Jul 01, 2025 at 12:20:58AM +0200, Mauro Carvalho Chehab wrote:
>Em Mon, 30 Jun 2025 13:53:55 -0600
>Jonathan Corbet <corbet@lwn.net> escreveu:
>
>> Sasha Levin <sashal@kernel.org> writes:
>>
>> > Add a comprehensive framework for formally documenting kernel APIs with
>> > inline specifications. This framework provides:
>> >
>> > - Structured API documentation with parameter specifications, return
>> > values, error conditions, and execution context requirements
>> > - Runtime validation capabilities for debugging (CONFIG_KAPI_RUNTIME_CHECKS)
>> > - Export of specifications via debugfs for tooling integration
>> > - Support for both internal kernel APIs and system calls
>> >
>> > The framework stores specifications in a dedicated ELF section and
>> > provides infrastructure for:
>> > - Compile-time validation of specifications
>> > - Runtime querying of API documentation
>> > - Machine-readable export formats
>> > - Integration with existing SYSCALL_DEFINE macros
>> >
>> > This commit introduces the core infrastructure without modifying any
>> > existing APIs. Subsequent patches will add specifications to individual
>> > subsystems.
>> >
>> > Signed-off-by: Sasha Levin <sashal@kernel.org>
>> > ---
>> > Documentation/admin-guide/kernel-api-spec.rst | 507 ++++++
>>
>> You need to add that file to index.rst in that directory or it won't be
>> pulled into the docs build.
>>
>> Wouldn't it be nice to integrate all this stuff with out existing
>> kerneldoc mechanism...? :)
>
>+1
>
>Having two different mechanisms (kapi and kerneldoc) makes a lot harder
>to maintain kAPI.
I hated the idea of not reusing kerneldoc.
My concern with kerneldoc was that I can't manipulate the
information it stores in the context of a kernel build. So for example,
I wasn't sure how I can expose information stored within kerneldoc via
debugfs on a running system (or how I can store it within the vmlinux
for later extraction from the binary built kernel).
I did some research based on your proposal, and I think I was incorrect
with the assumption above. I suppose we could do something like the
following:
1. Add new section patterns to doc_sect regex in to include API
specification sections: api-type, api-version, param-type, param-flags,
param-constraint, error-code, capability, signal, lock-req, since...
2. Create new output module (scripts/lib/kdoc/kdoc_apispec.py?) to
generate C macro invocations from parsed data.
Which will generate output like:
DEFINE_KERNEL_API_SPEC(function_name)
KAPI_DESCRIPTION("...")
KAPI_PARAM(0, "name", "type", "desc")
KAPI_PARAM_TYPE(KAPI_TYPE_INT)
KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
KAPI_PARAM_END
KAPI_END_SPEC
3. And then via makefile we can:
- Generate API specs from kerneldoc comments
- Include generated specs conditionally based on CONFIG_KERNEL_API_SPEC
Allowing us to just have these in the relevant source files:
#ifdef CONFIG_KERNEL_API_SPEC
#include "socket.apispec.h"
#endif
In theory, all of that will let us have something like the following in
kerneldoc:
- @api-type: syscall
- @api-version: 1
- @context-flags: KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE
- @param-type: family, KAPI_TYPE_INT
- @param-flags: family, KAPI_PARAM_IN
- @param-range: family, 0, 45
- @param-mask: type, SOCK_TYPE_MASK | SOCK_CLOEXEC | SOCK_NONBLOCK
- @error-code: -EAFNOSUPPORT, "Address family not supported"
- @error-condition: -EAFNOSUPPORT, "family < 0 || family >= NPROTO"
- @capability: CAP_NET_RAW, KAPI_CAP_GRANT_PERMISSION
- @capability-allows: CAP_NET_RAW, "Create SOCK_RAW sockets"
- @since: 2.0
- @return-type: KAPI_TYPE_FD
- @return-check: KAPI_RETURN_ERROR_CHECK
How does it sound? I'm pretty excited about the possiblity to align this
with kerneldoc. Please poke holes in the plan :)
--
Thanks,
Sasha
[Adding some of the ELISA folks, who are working in a related area and
might have thoughts on this. You can find the patch series under
discussion at:
https://lore.kernel.org/all/20250624180742.5795-1-sashal@kernel.org
]
Sasha Levin <sashal@kernel.org> writes:
> 1. Add new section patterns to doc_sect regex in to include API
> specification sections: api-type, api-version, param-type, param-flags,
> param-constraint, error-code, capability, signal, lock-req, since...
Easily enough done - you can never have too many regexes :)
> 2. Create new output module (scripts/lib/kdoc/kdoc_apispec.py?) to
> generate C macro invocations from parsed data.
>
> Which will generate output like:
>
> DEFINE_KERNEL_API_SPEC(function_name)
> KAPI_DESCRIPTION("...")
> KAPI_PARAM(0, "name", "type", "desc")
> KAPI_PARAM_TYPE(KAPI_TYPE_INT)
> KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
> KAPI_PARAM_END
> KAPI_END_SPEC
Also shouldn't be all that hard.
> 3. And then via makefile we can:
> - Generate API specs from kerneldoc comments
> - Include generated specs conditionally based on CONFIG_KERNEL_API_SPEC
>
> Allowing us to just have these in the relevant source files:
> #ifdef CONFIG_KERNEL_API_SPEC
> #include "socket.apispec.h"
> #endif
...seems like it should work.
> In theory, all of that will let us have something like the following in
> kerneldoc:
>
> - @api-type: syscall
> - @api-version: 1
> - @context-flags: KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE
> - @param-type: family, KAPI_TYPE_INT
> - @param-flags: family, KAPI_PARAM_IN
> - @param-range: family, 0, 45
> - @param-mask: type, SOCK_TYPE_MASK | SOCK_CLOEXEC | SOCK_NONBLOCK
> - @error-code: -EAFNOSUPPORT, "Address family not supported"
> - @error-condition: -EAFNOSUPPORT, "family < 0 || family >= NPROTO"
> - @capability: CAP_NET_RAW, KAPI_CAP_GRANT_PERMISSION
> - @capability-allows: CAP_NET_RAW, "Create SOCK_RAW sockets"
> - @since: 2.0
> - @return-type: KAPI_TYPE_FD
> - @return-check: KAPI_RETURN_ERROR_CHECK
>
> How does it sound? I'm pretty excited about the possiblity to align this
> with kerneldoc. Please poke holes in the plan :)
I think we could do it without all the @signs. We'd also want to see
how well we could integrate that information with the minimal structure
we already have: getting the return-value information into the Returns:
section, for example, and tying the parameter constraints to the
parameter descriptions we already have.
The other thing I would really like to see, to the extent we can, is
that a bunch of patches adding all this data to the source will actually
be accepted by the relevant maintainers. It would be a shame to get all
this infrastructure into place, then have things stall out due to
maintainer pushback. Maybe you should start by annotating the
scheduler-related system calls; if that works the rest should be a piece
of cake :)
Thanks,
jon
On Tue, Jul 01, 2025 at 01:01:27PM -0600, Jonathan Corbet wrote: >[Adding some of the ELISA folks, who are working in a related area and >might have thoughts on this. You can find the patch series under >discussion at: > > https://lore.kernel.org/all/20250624180742.5795-1-sashal@kernel.org Yup, we all met at OSS and reached the conclusion that we should lean towards a machine readable spec, which we thought was closer to my proposal than the kerneldoc work. However, with your suggestion, I think it makes more sense to go back to kerneldoc as that can be made machine readable. >> In theory, all of that will let us have something like the following in >> kerneldoc: >> >> - @api-type: syscall >> - @api-version: 1 >> - @context-flags: KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE >> - @param-type: family, KAPI_TYPE_INT >> - @param-flags: family, KAPI_PARAM_IN >> - @param-range: family, 0, 45 >> - @param-mask: type, SOCK_TYPE_MASK | SOCK_CLOEXEC | SOCK_NONBLOCK >> - @error-code: -EAFNOSUPPORT, "Address family not supported" >> - @error-condition: -EAFNOSUPPORT, "family < 0 || family >= NPROTO" >> - @capability: CAP_NET_RAW, KAPI_CAP_GRANT_PERMISSION >> - @capability-allows: CAP_NET_RAW, "Create SOCK_RAW sockets" >> - @since: 2.0 >> - @return-type: KAPI_TYPE_FD >> - @return-check: KAPI_RETURN_ERROR_CHECK >> >> How does it sound? I'm pretty excited about the possiblity to align this >> with kerneldoc. Please poke holes in the plan :) > >I think we could do it without all the @signs. We'd also want to see >how well we could integrate that information with the minimal structure >we already have: getting the return-value information into the Returns: >section, for example, and tying the parameter constraints to the >parameter descriptions we already have. Right! So I have a proof of concept which during the build process creates .apispec.h which are generated from kerneldoc and contain macros identical to the ones in my RFC. Here's an example of sys_mlock() spec: /** * sys_mlock - Lock pages in memory * @start: Starting address of memory range to lock * @len: Length of memory range to lock in bytes * * Locks pages in the specified address range into RAM, preventing them from * being paged to swap. Requires CAP_IPC_LOCK capability or RLIMIT_MEMLOCK * resource limit. * * long-desc: Locks pages in the specified address range into RAM, preventing * them from being paged to swap. Requires CAP_IPC_LOCK capability * or RLIMIT_MEMLOCK resource limit. * context-flags: KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE * param-type: start, KAPI_TYPE_UINT * param-flags: start, KAPI_PARAM_IN * param-constraint-type: start, KAPI_CONSTRAINT_NONE * param-constraint: start, Rounded down to page boundary * param-type: len, KAPI_TYPE_UINT * param-flags: len, KAPI_PARAM_IN * param-constraint-type: len, KAPI_CONSTRAINT_RANGE * param-range: len, 0, LONG_MAX * param-constraint: len, Rounded up to page boundary * return-type: KAPI_TYPE_INT * return-check-type: KAPI_RETURN_ERROR_CHECK * return-success: 0 * error-code: -ENOMEM, ENOMEM, Address range issue, * Some of the specified range is not mapped, has unmapped gaps, * or the lock would cause the number of mapped regions to exceed the limit. * error-code: -EPERM, EPERM, Insufficient privileges, * The caller is not privileged (no CAP_IPC_LOCK) and RLIMIT_MEMLOCK is 0. * error-code: -EINVAL, EINVAL, Address overflow, * The result of the addition start+len was less than start (arithmetic overflow). * error-code: -EAGAIN, EAGAIN, Some or all memory could not be locked, * Some or all of the specified address range could not be locked. * error-code: -EINTR, EINTR, Interrupted by signal, * The operation was interrupted by a fatal signal before completion. * error-code: -EFAULT, EFAULT, Bad address, * The specified address range contains invalid addresses that cannot be accessed. * since-version: 2.0 * lock: mmap_lock, KAPI_LOCK_RWLOCK * lock-acquired: true * lock-released: true * lock-desc: Process memory map write lock * signal: FATAL * signal-direction: KAPI_SIGNAL_RECEIVE * signal-action: KAPI_SIGNAL_ACTION_RETURN * signal-condition: Fatal signal pending * signal-desc: Fatal signals (SIGKILL) can interrupt the operation at two points: * when acquiring mmap_write_lock_killable() and during page population * in __mm_populate(). Returns -EINTR. Non-fatal signals do NOT interrupt * mlock - the operation continues even if SIGINT/SIGTERM are received. * signal-error: -EINTR * signal-timing: KAPI_SIGNAL_TIME_DURING * signal-priority: 0 * signal-interruptible: yes * signal-state-req: KAPI_SIGNAL_STATE_RUNNING * examples: mlock(addr, 4096); // Lock one page * mlock(addr, len); // Lock range of pages * notes: Memory locks do not stack - multiple calls on the same range can be * undone by a single munlock. Locks are not inherited by child processes. * Pages are locked on whole page boundaries. Commonly used by real-time * applications to prevent page faults during time-critical operations. * Also used for security to prevent sensitive data (e.g., cryptographic keys) * from being written to swap. Note: locked pages may still be saved to * swap during system suspend/hibernate. * * Tagged addresses are automatically handled via untagged_addr(). The operation * occurs in two phases: first VMAs are marked with VM_LOCKED, then pages are * populated into memory. When checking RLIMIT_MEMLOCK, the kernel optimizes * by recounting locked memory to avoid double-counting overlapping regions. * side-effect: KAPI_EFFECT_MODIFY_STATE | KAPI_EFFECT_ALLOC_MEMORY, process memory, Locks pages into physical memory, preventing swapping, reversible=yes * side-effect: KAPI_EFFECT_MODIFY_STATE, mm->locked_vm, Increases process locked memory counter, reversible=yes * side-effect: KAPI_EFFECT_ALLOC_MEMORY, physical pages, May allocate and populate page table entries, condition=Pages not already present, reversible=yes * side-effect: KAPI_EFFECT_MODIFY_STATE | KAPI_EFFECT_ALLOC_MEMORY, page faults, Triggers page faults to bring pages into memory, condition=Pages not already resident * side-effect: KAPI_EFFECT_MODIFY_STATE, VMA splitting, May split existing VMAs at lock boundaries, condition=Lock range partially overlaps existing VMA * state-trans: memory pages, swappable, locked in RAM, Pages become non-swappable and pinned in physical memory * state-trans: VMA flags, unlocked, VM_LOCKED set, Virtual memory area marked as locked * capability: CAP_IPC_LOCK, KAPI_CAP_BYPASS_CHECK, CAP_IPC_LOCK capability * capability-allows: Lock unlimited amount of memory (no RLIMIT_MEMLOCK enforcement) * capability-without: Must respect RLIMIT_MEMLOCK resource limit * capability-condition: Checked when RLIMIT_MEMLOCK is 0 or locking would exceed limit * capability-priority: 0 * constraint: RLIMIT_MEMLOCK Resource Limit, The RLIMIT_MEMLOCK soft resource limit specifies the maximum bytes of memory that may be locked into RAM. Unprivileged processes are restricted to this limit. CAP_IPC_LOCK capability allows bypassing this limit entirely. The limit is enforced per-process, not per-user. * constraint-expr: RLIMIT_MEMLOCK Resource Limit, locked_memory + request_size <= RLIMIT_MEMLOCK || CAP_IPC_LOCK * constraint: Memory Pressure and OOM, Locking large amounts of memory can cause system-wide memory pressure and potentially trigger the OOM killer. The kernel does not prevent locking memory that would destabilize the system. * constraint: Special Memory Areas, Some memory types cannot be locked or are silently skipped: VM_IO/VM_PFNMAP areas (device mappings) are skipped; Hugetlb pages are inherently pinned and skipped; DAX mappings are always present in memory and skipped; Secret memory (memfd_secret) mappings are skipped; VM_DROPPABLE memory cannot be locked and is skipped; Gate VMA (kernel entry point) is skipped; VM_LOCKED areas are already locked. These special areas are silently excluded without error. * * Context: Process context. May sleep. Takes mmap_lock for write. * * Return: 0 on success, negative error code on failure */ >The other thing I would really like to see, to the extent we can, is >that a bunch of patches adding all this data to the source will actually >be accepted by the relevant maintainers. It would be a shame to get all >this infrastructure into place, then have things stall out due to >maintainer pushback. Maybe you should start by annotating the >scheduler-related system calls; if that works the rest should be a piece >of cake :) In the RFC I've sent out I've specced out API from different subsystems to solicit some feedback on those, but so fair it's been quiet. I'll resend a "lean" RFC v3 with just the base macro spec infra + kerneldoc support + "tricker" sched API + "trickier" mm API. I'm thinking that if it's still quiet in a month or two I'll propose a talk at LPC around it, or maybe try and feedback/consensus during maintainer's summit. But yes, it doesn't make sense to take it in until we have an ack from a few larger subsystems. -- Thanks, Sasha
Sasha Levin <sashal@kernel.org> writes: > So I have a proof of concept which during the build process creates > .apispec.h which are generated from kerneldoc and contain macros > identical to the ones in my RFC. > > Here's an example of sys_mlock() spec: So I'm getting ahead of the game, but I have to ask some questions... > /** > * sys_mlock - Lock pages in memory > * @start: Starting address of memory range to lock > * @len: Length of memory range to lock in bytes > * > * Locks pages in the specified address range into RAM, preventing them from > * being paged to swap. Requires CAP_IPC_LOCK capability or RLIMIT_MEMLOCK > * resource limit. > * > * long-desc: Locks pages in the specified address range into RAM, preventing > * them from being paged to swap. Requires CAP_IPC_LOCK capability > * or RLIMIT_MEMLOCK resource limit. Why duplicate the long description? > * context-flags: KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE > * param-type: start, KAPI_TYPE_UINT This is something I wondered before; rather than a bunch of lengthy KAPI_* symbols, why not just say __u64 (or some other familiar type) here? > * param-flags: start, KAPI_PARAM_IN > * param-constraint-type: start, KAPI_CONSTRAINT_NONE > * param-constraint: start, Rounded down to page boundary > * param-type: len, KAPI_TYPE_UINT > * param-flags: len, KAPI_PARAM_IN > * param-constraint-type: len, KAPI_CONSTRAINT_RANGE > * param-range: len, 0, LONG_MAX > * param-constraint: len, Rounded up to page boundary > * return-type: KAPI_TYPE_INT > * return-check-type: KAPI_RETURN_ERROR_CHECK > * return-success: 0 > * error-code: -ENOMEM, ENOMEM, Address range issue, > * Some of the specified range is not mapped, has unmapped gaps, > * or the lock would cause the number of mapped regions to exceed the limit. > * error-code: -EPERM, EPERM, Insufficient privileges, > * The caller is not privileged (no CAP_IPC_LOCK) and RLIMIT_MEMLOCK is 0. > * error-code: -EINVAL, EINVAL, Address overflow, > * The result of the addition start+len was less than start (arithmetic overflow). > * error-code: -EAGAIN, EAGAIN, Some or all memory could not be locked, > * Some or all of the specified address range could not be locked. > * error-code: -EINTR, EINTR, Interrupted by signal, > * The operation was interrupted by a fatal signal before completion. > * error-code: -EFAULT, EFAULT, Bad address, > * The specified address range contains invalid addresses that cannot be accessed. > * since-version: 2.0 > * lock: mmap_lock, KAPI_LOCK_RWLOCK > * lock-acquired: true > * lock-released: true > * lock-desc: Process memory map write lock > * signal: FATAL > * signal-direction: KAPI_SIGNAL_RECEIVE > * signal-action: KAPI_SIGNAL_ACTION_RETURN > * signal-condition: Fatal signal pending > * signal-desc: Fatal signals (SIGKILL) can interrupt the operation at two points: > * when acquiring mmap_write_lock_killable() and during page population > * in __mm_populate(). Returns -EINTR. Non-fatal signals do NOT interrupt > * mlock - the operation continues even if SIGINT/SIGTERM are received. > * signal-error: -EINTR > * signal-timing: KAPI_SIGNAL_TIME_DURING > * signal-priority: 0 > * signal-interruptible: yes > * signal-state-req: KAPI_SIGNAL_STATE_RUNNING > * examples: mlock(addr, 4096); // Lock one page > * mlock(addr, len); // Lock range of pages > * notes: Memory locks do not stack - multiple calls on the same range can be > * undone by a single munlock. Locks are not inherited by child processes. > * Pages are locked on whole page boundaries. Commonly used by real-time > * applications to prevent page faults during time-critical operations. > * Also used for security to prevent sensitive data (e.g., cryptographic keys) > * from being written to swap. Note: locked pages may still be saved to > * swap during system suspend/hibernate. > * > * Tagged addresses are automatically handled via untagged_addr(). The operation > * occurs in two phases: first VMAs are marked with VM_LOCKED, then pages are > * populated into memory. When checking RLIMIT_MEMLOCK, the kernel optimizes > * by recounting locked memory to avoid double-counting overlapping regions. > * side-effect: KAPI_EFFECT_MODIFY_STATE | KAPI_EFFECT_ALLOC_MEMORY, process memory, Locks pages into physical memory, preventing swapping, reversible=yes I hope the really long lines starting here aren't the intended way to go...:) > * side-effect: KAPI_EFFECT_MODIFY_STATE, mm->locked_vm, Increases process locked memory counter, reversible=yes > * side-effect: KAPI_EFFECT_ALLOC_MEMORY, physical pages, May allocate and populate page table entries, condition=Pages not already present, reversible=yes > * side-effect: KAPI_EFFECT_MODIFY_STATE | KAPI_EFFECT_ALLOC_MEMORY, page faults, Triggers page faults to bring pages into memory, condition=Pages not already resident > * side-effect: KAPI_EFFECT_MODIFY_STATE, VMA splitting, May split existing VMAs at lock boundaries, condition=Lock range partially overlaps existing VMA > * state-trans: memory pages, swappable, locked in RAM, Pages become non-swappable and pinned in physical memory > * state-trans: VMA flags, unlocked, VM_LOCKED set, Virtual memory area marked as locked > * capability: CAP_IPC_LOCK, KAPI_CAP_BYPASS_CHECK, CAP_IPC_LOCK capability > * capability-allows: Lock unlimited amount of memory (no RLIMIT_MEMLOCK enforcement) > * capability-without: Must respect RLIMIT_MEMLOCK resource limit > * capability-condition: Checked when RLIMIT_MEMLOCK is 0 or locking would exceed limit > * capability-priority: 0 > * constraint: RLIMIT_MEMLOCK Resource Limit, The RLIMIT_MEMLOCK soft resource limit specifies the maximum bytes of memory that may be locked into RAM. Unprivileged processes are restricted to this limit. CAP_IPC_LOCK capability allows bypassing this limit entirely. The limit is enforced per-process, not per-user. > * constraint-expr: RLIMIT_MEMLOCK Resource Limit, locked_memory + request_size <= RLIMIT_MEMLOCK || CAP_IPC_LOCK > * constraint: Memory Pressure and OOM, Locking large amounts of memory can cause system-wide memory pressure and potentially trigger the OOM killer. The kernel does not prevent locking memory that would destabilize the system. > * constraint: Special Memory Areas, Some memory types cannot be locked or are silently skipped: VM_IO/VM_PFNMAP areas (device mappings) are skipped; Hugetlb pages are inherently pinned and skipped; DAX mappings are always present in memory and skipped; Secret memory (memfd_secret) mappings are skipped; VM_DROPPABLE memory cannot be locked and is skipped; Gate VMA (kernel entry point) is skipped; VM_LOCKED areas are already locked. These special areas are silently excluded without error. > * > * Context: Process context. May sleep. Takes mmap_lock for write. > * > * Return: 0 on success, negative error code on failure Both of these, of course, are much less informative versions of the data you have put up above; it would be nice to unify them somehow. Thanks, jon
On Tue, Jul 01, 2025 at 03:43:32PM -0600, Jonathan Corbet wrote: >Sasha Levin <sashal@kernel.org> writes: > >> So I have a proof of concept which during the build process creates >> .apispec.h which are generated from kerneldoc and contain macros >> identical to the ones in my RFC. >> >> Here's an example of sys_mlock() spec: > >So I'm getting ahead of the game, but I have to ask some questions... > >> /** >> * sys_mlock - Lock pages in memory >> * @start: Starting address of memory range to lock >> * @len: Length of memory range to lock in bytes >> * >> * Locks pages in the specified address range into RAM, preventing them from >> * being paged to swap. Requires CAP_IPC_LOCK capability or RLIMIT_MEMLOCK >> * resource limit. >> * >> * long-desc: Locks pages in the specified address range into RAM, preventing >> * them from being paged to swap. Requires CAP_IPC_LOCK capability >> * or RLIMIT_MEMLOCK resource limit. > >Why duplicate the long description? Will fix. >> * context-flags: KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE >> * param-type: start, KAPI_TYPE_UINT > >This is something I wondered before; rather than a bunch of lengthy >KAPI_* symbols, why not just say __u64 (or some other familiar type) >here? I think it gets tricky when we got to more complex types. For example, how do we represent a FD or a (struct sockaddr *)? With macros, KAPI_TYPE_FD or KAPI_TYPE_SOCKADDR make sense, but __sockaddr will be a bit confusing (I think). >> * param-flags: start, KAPI_PARAM_IN >> * param-constraint-type: start, KAPI_CONSTRAINT_NONE >> * param-constraint: start, Rounded down to page boundary >> * param-type: len, KAPI_TYPE_UINT >> * param-flags: len, KAPI_PARAM_IN >> * param-constraint-type: len, KAPI_CONSTRAINT_RANGE >> * param-range: len, 0, LONG_MAX >> * param-constraint: len, Rounded up to page boundary >> * return-type: KAPI_TYPE_INT >> * return-check-type: KAPI_RETURN_ERROR_CHECK >> * return-success: 0 >> * error-code: -ENOMEM, ENOMEM, Address range issue, >> * Some of the specified range is not mapped, has unmapped gaps, >> * or the lock would cause the number of mapped regions to exceed the limit. >> * error-code: -EPERM, EPERM, Insufficient privileges, >> * The caller is not privileged (no CAP_IPC_LOCK) and RLIMIT_MEMLOCK is 0. >> * error-code: -EINVAL, EINVAL, Address overflow, >> * The result of the addition start+len was less than start (arithmetic overflow). >> * error-code: -EAGAIN, EAGAIN, Some or all memory could not be locked, >> * Some or all of the specified address range could not be locked. >> * error-code: -EINTR, EINTR, Interrupted by signal, >> * The operation was interrupted by a fatal signal before completion. >> * error-code: -EFAULT, EFAULT, Bad address, >> * The specified address range contains invalid addresses that cannot be accessed. >> * since-version: 2.0 >> * lock: mmap_lock, KAPI_LOCK_RWLOCK >> * lock-acquired: true >> * lock-released: true >> * lock-desc: Process memory map write lock >> * signal: FATAL >> * signal-direction: KAPI_SIGNAL_RECEIVE >> * signal-action: KAPI_SIGNAL_ACTION_RETURN >> * signal-condition: Fatal signal pending >> * signal-desc: Fatal signals (SIGKILL) can interrupt the operation at two points: >> * when acquiring mmap_write_lock_killable() and during page population >> * in __mm_populate(). Returns -EINTR. Non-fatal signals do NOT interrupt >> * mlock - the operation continues even if SIGINT/SIGTERM are received. >> * signal-error: -EINTR >> * signal-timing: KAPI_SIGNAL_TIME_DURING >> * signal-priority: 0 >> * signal-interruptible: yes >> * signal-state-req: KAPI_SIGNAL_STATE_RUNNING >> * examples: mlock(addr, 4096); // Lock one page >> * mlock(addr, len); // Lock range of pages >> * notes: Memory locks do not stack - multiple calls on the same range can be >> * undone by a single munlock. Locks are not inherited by child processes. >> * Pages are locked on whole page boundaries. Commonly used by real-time >> * applications to prevent page faults during time-critical operations. >> * Also used for security to prevent sensitive data (e.g., cryptographic keys) >> * from being written to swap. Note: locked pages may still be saved to >> * swap during system suspend/hibernate. >> * >> * Tagged addresses are automatically handled via untagged_addr(). The operation >> * occurs in two phases: first VMAs are marked with VM_LOCKED, then pages are >> * populated into memory. When checking RLIMIT_MEMLOCK, the kernel optimizes >> * by recounting locked memory to avoid double-counting overlapping regions. >> * side-effect: KAPI_EFFECT_MODIFY_STATE | KAPI_EFFECT_ALLOC_MEMORY, process memory, Locks pages into physical memory, preventing swapping, reversible=yes > >I hope the really long lines starting here aren't the intended way to go...:) I guess that we have two options around more complex blocks like these. One, the longer lines you've pointed out. They are indeed long and difficult to read, but they present a relatively static and "not too interesting" information which users are likely to gloss over. The other one would look something like: side-effect: KAPI_EFFECT_MODIFY_STATE side-effect-type: KAPI_EFFECT_MODIFY_STATE side-effect-target: mm->locked_vm side-effect-description: Increases process locked memory counter side-effect-reversible: yes Which isn't as long, but it occupies a bunch of vertical real estate while not being too interesting for most of the readers. >> * side-effect: KAPI_EFFECT_MODIFY_STATE, mm->locked_vm, Increases process locked memory counter, reversible=yes >> * side-effect: KAPI_EFFECT_ALLOC_MEMORY, physical pages, May allocate and populate page table entries, condition=Pages not already present, reversible=yes >> * side-effect: KAPI_EFFECT_MODIFY_STATE | KAPI_EFFECT_ALLOC_MEMORY, page faults, Triggers page faults to bring pages into memory, condition=Pages not already resident >> * side-effect: KAPI_EFFECT_MODIFY_STATE, VMA splitting, May split existing VMAs at lock boundaries, condition=Lock range partially overlaps existing VMA >> * state-trans: memory pages, swappable, locked in RAM, Pages become non-swappable and pinned in physical memory >> * state-trans: VMA flags, unlocked, VM_LOCKED set, Virtual memory area marked as locked >> * capability: CAP_IPC_LOCK, KAPI_CAP_BYPASS_CHECK, CAP_IPC_LOCK capability >> * capability-allows: Lock unlimited amount of memory (no RLIMIT_MEMLOCK enforcement) >> * capability-without: Must respect RLIMIT_MEMLOCK resource limit >> * capability-condition: Checked when RLIMIT_MEMLOCK is 0 or locking would exceed limit >> * capability-priority: 0 >> * constraint: RLIMIT_MEMLOCK Resource Limit, The RLIMIT_MEMLOCK soft resource limit specifies the maximum bytes of memory that may be locked into RAM. Unprivileged processes are restricted to this limit. CAP_IPC_LOCK capability allows bypassing this limit entirely. The limit is enforced per-process, not per-user. >> * constraint-expr: RLIMIT_MEMLOCK Resource Limit, locked_memory + request_size <= RLIMIT_MEMLOCK || CAP_IPC_LOCK >> * constraint: Memory Pressure and OOM, Locking large amounts of memory can cause system-wide memory pressure and potentially trigger the OOM killer. The kernel does not prevent locking memory that would destabilize the system. >> * constraint: Special Memory Areas, Some memory types cannot be locked or are silently skipped: VM_IO/VM_PFNMAP areas (device mappings) are skipped; Hugetlb pages are inherently pinned and skipped; DAX mappings are always present in memory and skipped; Secret memory (memfd_secret) mappings are skipped; VM_DROPPABLE memory cannot be locked and is skipped; Gate VMA (kernel entry point) is skipped; VM_LOCKED areas are already locked. These special areas are silently excluded without error. >> * >> * Context: Process context. May sleep. Takes mmap_lock for write. >> * >> * Return: 0 on success, negative error code on failure > >Both of these, of course, are much less informative versions of the data >you have put up above; it would be nice to unify them somehow. Ack -- Thanks, Sasha
Em Tue, 1 Jul 2025 10:23:03 -0400
Sasha Levin <sashal@kernel.org> escreveu:
> On Tue, Jul 01, 2025 at 12:20:58AM +0200, Mauro Carvalho Chehab wrote:
> >Em Mon, 30 Jun 2025 13:53:55 -0600
> >Jonathan Corbet <corbet@lwn.net> escreveu:
> >
> >> Sasha Levin <sashal@kernel.org> writes:
> >>
> >> > Add a comprehensive framework for formally documenting kernel APIs with
> >> > inline specifications. This framework provides:
> >> >
> >> > - Structured API documentation with parameter specifications, return
> >> > values, error conditions, and execution context requirements
> >> > - Runtime validation capabilities for debugging (CONFIG_KAPI_RUNTIME_CHECKS)
> >> > - Export of specifications via debugfs for tooling integration
> >> > - Support for both internal kernel APIs and system calls
> >> >
> >> > The framework stores specifications in a dedicated ELF section and
> >> > provides infrastructure for:
> >> > - Compile-time validation of specifications
> >> > - Runtime querying of API documentation
> >> > - Machine-readable export formats
> >> > - Integration with existing SYSCALL_DEFINE macros
> >> >
> >> > This commit introduces the core infrastructure without modifying any
> >> > existing APIs. Subsequent patches will add specifications to individual
> >> > subsystems.
> >> >
> >> > Signed-off-by: Sasha Levin <sashal@kernel.org>
> >> > ---
> >> > Documentation/admin-guide/kernel-api-spec.rst | 507 ++++++
> >>
> >> You need to add that file to index.rst in that directory or it won't be
> >> pulled into the docs build.
> >>
> >> Wouldn't it be nice to integrate all this stuff with out existing
> >> kerneldoc mechanism...? :)
> >
> >+1
> >
> >Having two different mechanisms (kapi and kerneldoc) makes a lot harder
> >to maintain kAPI.
>
> I hated the idea of not reusing kerneldoc.
>
> My concern with kerneldoc was that I can't manipulate the
> information it stores in the context of a kernel build. So for example,
> I wasn't sure how I can expose information stored within kerneldoc via
> debugfs on a running system (or how I can store it within the vmlinux
> for later extraction from the binary built kernel).
>
> I did some research based on your proposal, and I think I was incorrect
> with the assumption above. I suppose we could do something like the
> following:
>
> 1. Add new section patterns to doc_sect regex in to include API
> specification sections: api-type, api-version, param-type, param-flags,
> param-constraint, error-code, capability, signal, lock-req, since...
>
> 2. Create new output module (scripts/lib/kdoc/kdoc_apispec.py?) to
> generate C macro invocations from parsed data.
>
> Which will generate output like:
>
> DEFINE_KERNEL_API_SPEC(function_name)
> KAPI_DESCRIPTION("...")
> KAPI_PARAM(0, "name", "type", "desc")
> KAPI_PARAM_TYPE(KAPI_TYPE_INT)
> KAPI_PARAM_FLAGS(KAPI_PARAM_IN)
> KAPI_PARAM_END
> KAPI_END_SPEC
> 3. And then via makefile we can:
> - Generate API specs from kerneldoc comments
> - Include generated specs conditionally based on CONFIG_KERNEL_API_SPEC
>
> Allowing us to just have these in the relevant source files:
> #ifdef CONFIG_KERNEL_API_SPEC
> #include "socket.apispec.h"
> #endif
>
>
> In theory, all of that will let us have something like the following in
> kerneldoc:
>
> - @api-type: syscall
> - @api-version: 1
> - @context-flags: KAPI_CTX_PROCESS | KAPI_CTX_SLEEPABLE
> - @param-type: family, KAPI_TYPE_INT
> - @param-flags: family, KAPI_PARAM_IN
> - @param-range: family, 0, 45
> - @param-mask: type, SOCK_TYPE_MASK | SOCK_CLOEXEC | SOCK_NONBLOCK
> - @error-code: -EAFNOSUPPORT, "Address family not supported"
> - @error-condition: -EAFNOSUPPORT, "family < 0 || family >= NPROTO"
> - @capability: CAP_NET_RAW, KAPI_CAP_GRANT_PERMISSION
> - @capability-allows: CAP_NET_RAW, "Create SOCK_RAW sockets"
> - @since: 2.0
> - @return-type: KAPI_TYPE_FD
> - @return-check: KAPI_RETURN_ERROR_CHECK
>
> How does it sound? I'm pretty excited about the possiblity to align this
> with kerneldoc. Please poke holes in the plan :)
Sounds like a plan!
We did something somewhat similar on IGT.
The python classes there were written with the goal to document
tests, so its examples are related to test docs, but I wrote it
to be generic.
There, all fields comes form a JSON file like this:
https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/blob/master/tests/intel/xe_test_config.json?ref_type=heads
which describes what fields will be used. It also lists file
patterns that will use it. The fields allow hierarchical
grouping, with could be interesting for some types of fields.
From the json example (I dropped the optional field description
from the example, to make it cleaner):
"Category": {
"Mega feature": {
"Sub-category": {},
}
...
"Test category": {},
"Issue": {},
...
The hierarchical part is useful to properly order kapi content
without the need to add multiple Sphinx markups to manually reorder
the output inside the .rst files.
(*) I would avoid hardcoding the fields/structures, as eventually
we may need more flexibility to add fields and/or having some
fields that are specific, for instance, to debugfs or sysfs.
The python class it uses is at:
https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/blob/master/scripts/test_list.py?ref_type=heads
and caller is at:
https://gitlab.freedesktop.org/drm/igt-gpu-tools/-/blob/master/scripts/igt_doc.py?ref_type=heads
Eventually you may find something useful there. If so, feel free to
pick from it.
Regards,
Mauro
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