From: Steven Rostedt <rostedt@goodmis.org>

Most architectures use pt_regs within ftrace_regs making a lot of the
accessor functions just calls to the pt_regs internally. Instead of
duplication this effort, use a HAVE_ARCH_FTRACE_REGS for architectures
that have their own ftrace_regs that is not based on pt_regs and will
define all the accessor functions, and for the architectures that just use
pt_regs, it will leave it undefined, and the default accessor functions
will be used.

Note, this will also make it easier to add new accessor functions to
ftrace_regs as it will mean having to touch less architectures.

Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 arch/arm64/include/asm/ftrace.h     |  1 +
 arch/loongarch/include/asm/ftrace.h | 25 +-------------------
 arch/powerpc/include/asm/ftrace.h   | 26 +--------------------
 arch/riscv/include/asm/ftrace.h     |  1 +
 arch/s390/include/asm/ftrace.h      | 26 +--------------------
 arch/x86/include/asm/ftrace.h       | 21 +----------------
 include/linux/ftrace.h              | 32 ++++++-------------------
 include/linux/ftrace_regs.h         | 36 +++++++++++++++++++++++++++++
 8 files changed, 49 insertions(+), 119 deletions(-)
 create mode 100644 include/linux/ftrace_regs.h

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index bbb69c7751b9..5ccff4de7f09 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -54,6 +54,7 @@ extern void return_to_handler(void);
 unsigned long ftrace_call_adjust(unsigned long addr);
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
+#define HAVE_ARCH_FTRACE_REGS
 struct dyn_ftrace;
 struct ftrace_ops;
 struct ftrace_regs;
diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
index 0e15d36ce251..8f13eaeaa325 100644
--- a/arch/loongarch/include/asm/ftrace.h
+++ b/arch/loongarch/include/asm/ftrace.h
@@ -43,43 +43,20 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent);
 
 #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
 struct ftrace_ops;
-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
 
-struct __arch_ftrace_regs {
-	struct pt_regs regs;
-};
+#include <linux/ftrace_regs.h>
 
 static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
 {
 	return &arch_ftrace_regs(fregs)->regs;
 }
 
-static __always_inline unsigned long
-ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
-{
-	return instruction_pointer(&arch_ftrace_regs(fregs)->regs);
-}
-
 static __always_inline void
 ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, unsigned long ip)
 {
 	instruction_pointer_set(&arch_ftrace_regs(fregs)->regs, ip);
 }
 
-#define ftrace_regs_get_argument(fregs, n) \
-	regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
-#define ftrace_regs_get_stack_pointer(fregs) \
-	kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_return_value(fregs) \
-	regs_return_value(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_set_return_value(fregs, ret) \
-	regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
-#define ftrace_override_function_with_return(fregs) \
-	override_function_with_return(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_query_register_offset(name) \
-	regs_query_register_offset(name)
-
 #define ftrace_graph_func ftrace_graph_func
 void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
 		       struct ftrace_ops *op, struct ftrace_regs *fregs);
diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index e299fd47d201..0edfb874eb02 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -32,12 +32,7 @@ struct dyn_arch_ftrace {
 int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
 #define ftrace_init_nop ftrace_init_nop
 
-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
-
-struct __arch_ftrace_regs {
-	struct pt_regs regs;
-};
+#include <linux/ftrace_regs.h>
 
 static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
 {
@@ -52,25 +47,6 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
 	regs_set_return_ip(&arch_ftrace_regs(fregs)->regs, ip);
 }
 
-static __always_inline unsigned long
-ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
-{
-	return instruction_pointer(&arch_ftrace_regs(fregs)->regs);
-}
-
-#define ftrace_regs_get_argument(fregs, n) \
-	regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
-#define ftrace_regs_get_stack_pointer(fregs) \
-	kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_return_value(fregs) \
-	regs_return_value(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_set_return_value(fregs, ret) \
-	regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
-#define ftrace_override_function_with_return(fregs) \
-	override_function_with_return(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_query_register_offset(name) \
-	regs_query_register_offset(name)
-
 struct ftrace_ops;
 
 #define ftrace_graph_func ftrace_graph_func
diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
index c6bcdff105b5..3d66437a1029 100644
--- a/arch/riscv/include/asm/ftrace.h
+++ b/arch/riscv/include/asm/ftrace.h
@@ -125,6 +125,7 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
 #define arch_ftrace_get_regs(regs) NULL
+#define HAVE_ARCH_FTRACE_REGS
 struct ftrace_ops;
 struct ftrace_regs;
 #define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 1498d0a9c762..fc97d75dc752 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -51,12 +51,7 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
 	return addr;
 }
 
-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
-
-struct __arch_ftrace_regs {
-	struct pt_regs regs;
-};
+#include <linux/ftrace_regs.h>
 
 static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
 {
@@ -84,12 +79,6 @@ static __always_inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph
 }
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
-static __always_inline unsigned long
-ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs)
-{
-	return arch_ftrace_regs(fregs)->regs.psw.addr;
-}
-
 static __always_inline void
 ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
 				    unsigned long ip)
@@ -97,19 +86,6 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
 	arch_ftrace_regs(fregs)->regs.psw.addr = ip;
 }
 
-#define ftrace_regs_get_argument(fregs, n) \
-	regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
-#define ftrace_regs_get_stack_pointer(fregs) \
-	kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_return_value(fregs) \
-	regs_return_value(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_set_return_value(fregs, ret) \
-	regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
-#define ftrace_override_function_with_return(fregs) \
-	override_function_with_return(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_query_register_offset(name) \
-	regs_query_register_offset(name)
-
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 /*
  * When an ftrace registered caller is tracing a function that is
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 87943f7a299b..8f02d28c571a 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -33,12 +33,8 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
 }
 
 #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
 
-struct __arch_ftrace_regs {
-	struct pt_regs		regs;
-};
+#include <linux/ftrace_regs.h>
 
 static __always_inline struct pt_regs *
 arch_ftrace_get_regs(struct ftrace_regs *fregs)
@@ -52,21 +48,6 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs)
 #define ftrace_regs_set_instruction_pointer(fregs, _ip)	\
 	do { arch_ftrace_regs(fregs)->regs.ip = (_ip); } while (0)
 
-#define ftrace_regs_get_instruction_pointer(fregs) \
-	arch_ftrace_regs(fregs)->regs.ip)
-
-#define ftrace_regs_get_argument(fregs, n) \
-	regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
-#define ftrace_regs_get_stack_pointer(fregs) \
-	kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_return_value(fregs) \
-	regs_return_value(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_set_return_value(fregs, ret) \
-	regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
-#define ftrace_override_function_with_return(fregs) \
-	override_function_with_return(&arch_ftrace_regs(fregs)->regs)
-#define ftrace_regs_query_register_offset(name) \
-	regs_query_register_offset(name)
 
 struct ftrace_ops;
 #define ftrace_graph_func ftrace_graph_func
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index f7d4f152f84d..c96f9b0eb86e 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -113,6 +113,8 @@ static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *val
 
 #ifdef CONFIG_FUNCTION_TRACER
 
+#include <linux/ftrace_regs.h>
+
 extern int ftrace_enabled;
 
 /**
@@ -150,14 +152,11 @@ struct ftrace_regs {
 #define ftrace_regs_size()	sizeof(struct __arch_ftrace_regs)
 
 #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
-
-struct __arch_ftrace_regs {
-	struct pt_regs		regs;
-};
-
-struct ftrace_regs;
-#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
-
+/*
+ * Architectures that define HAVE_DYNAMIC_FTRACE_WITH_ARGS must define their own
+ * arch_ftrace_get_regs() where it only returns pt_regs *if* it is fully
+ * populated. It should return NULL otherwise.
+ */
 static inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
 {
 	return &arch_ftrace_regs(fregs)->regs;
@@ -191,23 +190,6 @@ static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs)
 	return ftrace_get_regs(fregs) != NULL;
 }
 
-#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
-#define ftrace_regs_get_instruction_pointer(fregs) \
-	instruction_pointer(ftrace_get_regs(fregs))
-#define ftrace_regs_get_argument(fregs, n) \
-	regs_get_kernel_argument(ftrace_get_regs(fregs), n)
-#define ftrace_regs_get_stack_pointer(fregs) \
-	kernel_stack_pointer(ftrace_get_regs(fregs))
-#define ftrace_regs_return_value(fregs) \
-	regs_return_value(ftrace_get_regs(fregs))
-#define ftrace_regs_set_return_value(fregs, ret) \
-	regs_set_return_value(ftrace_get_regs(fregs), ret)
-#define ftrace_override_function_with_return(fregs) \
-	override_function_with_return(ftrace_get_regs(fregs))
-#define ftrace_regs_query_register_offset(name) \
-	regs_query_register_offset(name)
-#endif
-
 typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
 			      struct ftrace_ops *op, struct ftrace_regs *fregs);
 
diff --git a/include/linux/ftrace_regs.h b/include/linux/ftrace_regs.h
new file mode 100644
index 000000000000..1cdd4bfa440b
--- /dev/null
+++ b/include/linux/ftrace_regs.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_FTRACE_TYPES_H
+#define _LINUX_FTRACE_TYPES_H
+
+/*
+ * For archs that just copy pt_regs in ftrace regs, it can use this default.
+ * If an architecture does not use pt_regs, it must define all the below
+ * accessor functions.
+ */
+#ifndef HAVE_ARCH_FTRACE_REGS
+struct __arch_ftrace_regs {
+	struct pt_regs		regs;
+};
+
+#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
+
+struct ftrace_regs;
+
+#define ftrace_regs_get_instruction_pointer(fregs) \
+	instruction_pointer(arch_ftrace_get_regs(fregs))
+#define ftrace_regs_get_argument(fregs, n) \
+	regs_get_kernel_argument(arch_ftrace_get_regs(fregs), n)
+#define ftrace_regs_get_stack_pointer(fregs) \
+	kernel_stack_pointer(arch_ftrace_get_regs(fregs))
+#define ftrace_regs_return_value(fregs) \
+	regs_return_value(arch_ftrace_get_regs(fregs))
+#define ftrace_regs_set_return_value(fregs, ret) \
+	regs_set_return_value(arch_ftrace_get_regs(fregs), ret)
+#define ftrace_override_function_with_return(fregs) \
+	override_function_with_return(arch_ftrace_get_regs(fregs))
+#define ftrace_regs_query_register_offset(name) \
+	regs_query_register_offset(name)
+
+#endif /* HAVE_ARCH_FTRACE_REGS */
+
+#endif /* _LINUX_FTRACE_TYPES_H */
-- 
2.45.2

Loongarch maintainers, please note the below comments!


On Tue, 08 Oct 2024 19:05:29 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:


> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index bbb69c7751b9..5ccff4de7f09 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -54,6 +54,7 @@ extern void return_to_handler(void);
>  unsigned long ftrace_call_adjust(unsigned long addr);
>  
>  #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
> +#define HAVE_ARCH_FTRACE_REGS
>  struct dyn_ftrace;
>  struct ftrace_ops;
>  struct ftrace_regs;
> diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
> index 0e15d36ce251..8f13eaeaa325 100644
> --- a/arch/loongarch/include/asm/ftrace.h
> +++ b/arch/loongarch/include/asm/ftrace.h
> @@ -43,43 +43,20 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent);
>  
>  #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
>  struct ftrace_ops;
> -struct ftrace_regs;
> -#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
>  
> -struct __arch_ftrace_regs {
> -	struct pt_regs regs;
> -};
> +#include <linux/ftrace_regs.h>
>  
>  static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
>  {
>  	return &arch_ftrace_regs(fregs)->regs;
>  }

The above function is incorrect. I know I just added the comment about how
it is to work below, but if pt_regs is not fully filled, then
arch_ftrace_get_regs() must return NULL.

This is because if a callback is registered with ftrace, and forgets to add
the FTRACE_OPS_FL_SAVE_REGS flag, then when it does:

	regs = ftrace_get_regs(fregs);

it should get NULL and not a partially filled pt_regs set. Because the API
is that ftrace_get_regs() will return either a full pt_regs (where the
caller can know that it has all the correct registers) or NULL where it
does not have any registers.

It's an all or nothing approach.

You can see x86 has:

static __always_inline struct pt_regs *
arch_ftrace_get_regs(struct ftrace_regs *fregs)
{
	/* Only when FL_SAVE_REGS is set, cs will be non zero */
	if (!arch_ftrace_regs(fregs)->regs.cs)
		return NULL;
	return &arch_ftrace_regs(fregs)->regs;
}

Where it checks if regs.cs is set to determine if it has all the regs or
not.

Please do something similar for your architecture.

>  
> -static __always_inline unsigned long
> -ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
> -{
> -	return instruction_pointer(&arch_ftrace_regs(fregs)->regs);
> -}
> -
>  static __always_inline void
>  ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, unsigned long ip)
>  {
>  	instruction_pointer_set(&arch_ftrace_regs(fregs)->regs, ip);
>  }
>  
> 


> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index f7d4f152f84d..c96f9b0eb86e 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -113,6 +113,8 @@ static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *val
>  
>  #ifdef CONFIG_FUNCTION_TRACER
>  
> +#include <linux/ftrace_regs.h>
> +
>  extern int ftrace_enabled;
>  
>  /**
> @@ -150,14 +152,11 @@ struct ftrace_regs {
>  #define ftrace_regs_size()	sizeof(struct __arch_ftrace_regs)
>  
>  #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
> -
> -struct __arch_ftrace_regs {
> -	struct pt_regs		regs;
> -};
> -
> -struct ftrace_regs;
> -#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
> -
> +/*
> + * Architectures that define HAVE_DYNAMIC_FTRACE_WITH_ARGS must define their own
> + * arch_ftrace_get_regs() where it only returns pt_regs *if* it is fully
> + * populated. It should return NULL otherwise.
> + */

I'm adding the above comment to help other architectures know of this requirement.

>  static inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
>  {
>  	return &arch_ftrace_regs(fregs)->regs;


-- Steve

On Tue, Oct 08, 2024 at 07:05:29PM -0400, Steven Rostedt wrote:
> From: Steven Rostedt <rostedt@goodmis.org>
> 
> Most architectures use pt_regs within ftrace_regs making a lot of the
> accessor functions just calls to the pt_regs internally. Instead of
> duplication this effort, use a HAVE_ARCH_FTRACE_REGS for architectures
> that have their own ftrace_regs that is not based on pt_regs and will
> define all the accessor functions, and for the architectures that just use
> pt_regs, it will leave it undefined, and the default accessor functions
> will be used.
> 
> Note, this will also make it easier to add new accessor functions to
> ftrace_regs as it will mean having to touch less architectures.
> 
> Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
...
>  arch/s390/include/asm/ftrace.h      | 26 +--------------------

Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390

On Tue, 08 Oct 2024 19:05:29 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: Steven Rostedt <rostedt@goodmis.org>
> 
> Most architectures use pt_regs within ftrace_regs making a lot of the
> accessor functions just calls to the pt_regs internally. Instead of
> duplication this effort, use a HAVE_ARCH_FTRACE_REGS for architectures
> that have their own ftrace_regs that is not based on pt_regs and will
> define all the accessor functions, and for the architectures that just use
> pt_regs, it will leave it undefined, and the default accessor functions
> will be used.
> 
> Note, this will also make it easier to add new accessor functions to
> ftrace_regs as it will mean having to touch less architectures.
> 
> Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
>  arch/arm64/include/asm/ftrace.h     |  1 +
>  arch/loongarch/include/asm/ftrace.h | 25 +-------------------
>  arch/powerpc/include/asm/ftrace.h   | 26 +--------------------
>  arch/riscv/include/asm/ftrace.h     |  1 +
>  arch/s390/include/asm/ftrace.h      | 26 +--------------------
>  arch/x86/include/asm/ftrace.h       | 21 +----------------
>  include/linux/ftrace.h              | 32 ++++++-------------------
>  include/linux/ftrace_regs.h         | 36 +++++++++++++++++++++++++++++
>  8 files changed, 49 insertions(+), 119 deletions(-)
>  create mode 100644 include/linux/ftrace_regs.h
> 
> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index bbb69c7751b9..5ccff4de7f09 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -54,6 +54,7 @@ extern void return_to_handler(void);
>  unsigned long ftrace_call_adjust(unsigned long addr);
>  
>  #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
> +#define HAVE_ARCH_FTRACE_REGS
>  struct dyn_ftrace;
>  struct ftrace_ops;
>  struct ftrace_regs;
> diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h
> index 0e15d36ce251..8f13eaeaa325 100644
> --- a/arch/loongarch/include/asm/ftrace.h
> +++ b/arch/loongarch/include/asm/ftrace.h
> @@ -43,43 +43,20 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent);
>  
>  #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
>  struct ftrace_ops;
> -struct ftrace_regs;
> -#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
>  
> -struct __arch_ftrace_regs {
> -	struct pt_regs regs;
> -};
> +#include <linux/ftrace_regs.h>
>  
>  static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
>  {
>  	return &arch_ftrace_regs(fregs)->regs;
>  }
>  
> -static __always_inline unsigned long
> -ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
> -{
> -	return instruction_pointer(&arch_ftrace_regs(fregs)->regs);
> -}
> -
>  static __always_inline void
>  ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, unsigned long ip)
>  {
>  	instruction_pointer_set(&arch_ftrace_regs(fregs)->regs, ip);
>  }
>  
> -#define ftrace_regs_get_argument(fregs, n) \
> -	regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
> -#define ftrace_regs_get_stack_pointer(fregs) \
> -	kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_return_value(fregs) \
> -	regs_return_value(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_set_return_value(fregs, ret) \
> -	regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
> -#define ftrace_override_function_with_return(fregs) \
> -	override_function_with_return(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_query_register_offset(name) \
> -	regs_query_register_offset(name)
> -
>  #define ftrace_graph_func ftrace_graph_func
>  void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,
>  		       struct ftrace_ops *op, struct ftrace_regs *fregs);
> diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
> index e299fd47d201..0edfb874eb02 100644
> --- a/arch/powerpc/include/asm/ftrace.h
> +++ b/arch/powerpc/include/asm/ftrace.h
> @@ -32,12 +32,7 @@ struct dyn_arch_ftrace {
>  int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
>  #define ftrace_init_nop ftrace_init_nop
>  
> -struct ftrace_regs;
> -#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
> -
> -struct __arch_ftrace_regs {
> -	struct pt_regs regs;
> -};
> +#include <linux/ftrace_regs.h>
>  
>  static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
>  {
> @@ -52,25 +47,6 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
>  	regs_set_return_ip(&arch_ftrace_regs(fregs)->regs, ip);
>  }
>  
> -static __always_inline unsigned long
> -ftrace_regs_get_instruction_pointer(struct ftrace_regs *fregs)
> -{
> -	return instruction_pointer(&arch_ftrace_regs(fregs)->regs);
> -}
> -
> -#define ftrace_regs_get_argument(fregs, n) \
> -	regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
> -#define ftrace_regs_get_stack_pointer(fregs) \
> -	kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_return_value(fregs) \
> -	regs_return_value(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_set_return_value(fregs, ret) \
> -	regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
> -#define ftrace_override_function_with_return(fregs) \
> -	override_function_with_return(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_query_register_offset(name) \
> -	regs_query_register_offset(name)
> -
>  struct ftrace_ops;
>  
>  #define ftrace_graph_func ftrace_graph_func
> diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
> index c6bcdff105b5..3d66437a1029 100644
> --- a/arch/riscv/include/asm/ftrace.h
> +++ b/arch/riscv/include/asm/ftrace.h
> @@ -125,6 +125,7 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);
>  
>  #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS
>  #define arch_ftrace_get_regs(regs) NULL
> +#define HAVE_ARCH_FTRACE_REGS
>  struct ftrace_ops;
>  struct ftrace_regs;
>  #define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
> diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
> index 1498d0a9c762..fc97d75dc752 100644
> --- a/arch/s390/include/asm/ftrace.h
> +++ b/arch/s390/include/asm/ftrace.h
> @@ -51,12 +51,7 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
>  	return addr;
>  }
>  
> -struct ftrace_regs;
> -#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
> -
> -struct __arch_ftrace_regs {
> -	struct pt_regs regs;
> -};
> +#include <linux/ftrace_regs.h>
>  
>  static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
>  {
> @@ -84,12 +79,6 @@ static __always_inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph
>  }
>  #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
>  
> -static __always_inline unsigned long
> -ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs)
> -{
> -	return arch_ftrace_regs(fregs)->regs.psw.addr;
> -}
> -
>  static __always_inline void
>  ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
>  				    unsigned long ip)
> @@ -97,19 +86,6 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,
>  	arch_ftrace_regs(fregs)->regs.psw.addr = ip;
>  }
>  
> -#define ftrace_regs_get_argument(fregs, n) \
> -	regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
> -#define ftrace_regs_get_stack_pointer(fregs) \
> -	kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_return_value(fregs) \
> -	regs_return_value(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_set_return_value(fregs, ret) \
> -	regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
> -#define ftrace_override_function_with_return(fregs) \
> -	override_function_with_return(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_query_register_offset(name) \
> -	regs_query_register_offset(name)
> -
>  #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
>  /*
>   * When an ftrace registered caller is tracing a function that is
> diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
> index 87943f7a299b..8f02d28c571a 100644
> --- a/arch/x86/include/asm/ftrace.h
> +++ b/arch/x86/include/asm/ftrace.h
> @@ -33,12 +33,8 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr)
>  }
>  
>  #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
> -struct ftrace_regs;
> -#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
>  
> -struct __arch_ftrace_regs {
> -	struct pt_regs		regs;
> -};
> +#include <linux/ftrace_regs.h>
>  
>  static __always_inline struct pt_regs *
>  arch_ftrace_get_regs(struct ftrace_regs *fregs)
> @@ -52,21 +48,6 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs)
>  #define ftrace_regs_set_instruction_pointer(fregs, _ip)	\
>  	do { arch_ftrace_regs(fregs)->regs.ip = (_ip); } while (0)
>  
> -#define ftrace_regs_get_instruction_pointer(fregs) \
> -	arch_ftrace_regs(fregs)->regs.ip)
> -
> -#define ftrace_regs_get_argument(fregs, n) \
> -	regs_get_kernel_argument(&arch_ftrace_regs(fregs)->regs, n)
> -#define ftrace_regs_get_stack_pointer(fregs) \
> -	kernel_stack_pointer(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_return_value(fregs) \
> -	regs_return_value(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_set_return_value(fregs, ret) \
> -	regs_set_return_value(&arch_ftrace_regs(fregs)->regs, ret)
> -#define ftrace_override_function_with_return(fregs) \
> -	override_function_with_return(&arch_ftrace_regs(fregs)->regs)
> -#define ftrace_regs_query_register_offset(name) \
> -	regs_query_register_offset(name)
>  
>  struct ftrace_ops;
>  #define ftrace_graph_func ftrace_graph_func
> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index f7d4f152f84d..c96f9b0eb86e 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -113,6 +113,8 @@ static inline int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *val
>  
>  #ifdef CONFIG_FUNCTION_TRACER
>  
> +#include <linux/ftrace_regs.h>
> +
>  extern int ftrace_enabled;
>  
>  /**
> @@ -150,14 +152,11 @@ struct ftrace_regs {
>  #define ftrace_regs_size()	sizeof(struct __arch_ftrace_regs)
>  
>  #ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
> -
> -struct __arch_ftrace_regs {
> -	struct pt_regs		regs;
> -};
> -
> -struct ftrace_regs;
> -#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
> -
> +/*
> + * Architectures that define HAVE_DYNAMIC_FTRACE_WITH_ARGS must define their own
> + * arch_ftrace_get_regs() where it only returns pt_regs *if* it is fully
> + * populated. It should return NULL otherwise.
> + */
>  static inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
>  {
>  	return &arch_ftrace_regs(fregs)->regs;
> @@ -191,23 +190,6 @@ static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs)
>  	return ftrace_get_regs(fregs) != NULL;
>  }
>  
> -#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
> -#define ftrace_regs_get_instruction_pointer(fregs) \
> -	instruction_pointer(ftrace_get_regs(fregs))
> -#define ftrace_regs_get_argument(fregs, n) \
> -	regs_get_kernel_argument(ftrace_get_regs(fregs), n)
> -#define ftrace_regs_get_stack_pointer(fregs) \
> -	kernel_stack_pointer(ftrace_get_regs(fregs))
> -#define ftrace_regs_return_value(fregs) \
> -	regs_return_value(ftrace_get_regs(fregs))
> -#define ftrace_regs_set_return_value(fregs, ret) \
> -	regs_set_return_value(ftrace_get_regs(fregs), ret)
> -#define ftrace_override_function_with_return(fregs) \
> -	override_function_with_return(ftrace_get_regs(fregs))
> -#define ftrace_regs_query_register_offset(name) \
> -	regs_query_register_offset(name)
> -#endif
> -
>  typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip,
>  			      struct ftrace_ops *op, struct ftrace_regs *fregs);
>  
> diff --git a/include/linux/ftrace_regs.h b/include/linux/ftrace_regs.h
> new file mode 100644
> index 000000000000..1cdd4bfa440b
> --- /dev/null
> +++ b/include/linux/ftrace_regs.h
> @@ -0,0 +1,36 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_FTRACE_TYPES_H
> +#define _LINUX_FTRACE_TYPES_H
               ^^^^^^^^^^^^^^^^  Is this _LINUX_FTRACE_REGS_H?


> +
> +/*
> + * For archs that just copy pt_regs in ftrace regs, it can use this default.
> + * If an architecture does not use pt_regs, it must define all the below
> + * accessor functions.
> + */
> +#ifndef HAVE_ARCH_FTRACE_REGS
> +struct __arch_ftrace_regs {
> +	struct pt_regs		regs;
> +};
> +
> +#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
> +
> +struct ftrace_regs;
> +
> +#define ftrace_regs_get_instruction_pointer(fregs) \
> +	instruction_pointer(arch_ftrace_get_regs(fregs))
> +#define ftrace_regs_get_argument(fregs, n) \
> +	regs_get_kernel_argument(arch_ftrace_get_regs(fregs), n)
> +#define ftrace_regs_get_stack_pointer(fregs) \
> +	kernel_stack_pointer(arch_ftrace_get_regs(fregs))
> +#define ftrace_regs_return_value(fregs) \
> +	regs_return_value(arch_ftrace_get_regs(fregs))
> +#define ftrace_regs_set_return_value(fregs, ret) \
> +	regs_set_return_value(arch_ftrace_get_regs(fregs), ret)
> +#define ftrace_override_function_with_return(fregs) \
> +	override_function_with_return(arch_ftrace_get_regs(fregs))
> +#define ftrace_regs_query_register_offset(name) \
> +	regs_query_register_offset(name)
> +
> +#endif /* HAVE_ARCH_FTRACE_REGS */
> +
> +#endif /* _LINUX_FTRACE_TYPES_H */

Ditto.

Others looks good to me.

Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thank you!


> -- 
> 2.45.2
> 
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

On Wed, 9 Oct 2024 13:47:23 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:

> > --- /dev/null
> > +++ b/include/linux/ftrace_regs.h
> > @@ -0,0 +1,36 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef _LINUX_FTRACE_TYPES_H
> > +#define _LINUX_FTRACE_TYPES_H  
>                ^^^^^^^^^^^^^^^^  Is this _LINUX_FTRACE_REGS_H?

Ah, I originally called it ftrace_types.h, but later decided that name
didn't really fit. I changed all references to it but this one.

Thanks for catching this.

> 
> 
> > +
> > +/*
> > + * For archs that just copy pt_regs in ftrace regs, it can use this default.
> > + * If an architecture does not use pt_regs, it must define all the below
> > + * accessor functions.
> > + */
> > +#ifndef HAVE_ARCH_FTRACE_REGS
> > +struct __arch_ftrace_regs {
> > +	struct pt_regs		regs;
> > +};
> > +
> > +#define arch_ftrace_regs(fregs) ((struct __arch_ftrace_regs *)(fregs))
> > +
> > +struct ftrace_regs;
> > +
> > +#define ftrace_regs_get_instruction_pointer(fregs) \
> > +	instruction_pointer(arch_ftrace_get_regs(fregs))
> > +#define ftrace_regs_get_argument(fregs, n) \
> > +	regs_get_kernel_argument(arch_ftrace_get_regs(fregs), n)
> > +#define ftrace_regs_get_stack_pointer(fregs) \
> > +	kernel_stack_pointer(arch_ftrace_get_regs(fregs))
> > +#define ftrace_regs_return_value(fregs) \
> > +	regs_return_value(arch_ftrace_get_regs(fregs))
> > +#define ftrace_regs_set_return_value(fregs, ret) \
> > +	regs_set_return_value(arch_ftrace_get_regs(fregs), ret)
> > +#define ftrace_override_function_with_return(fregs) \
> > +	override_function_with_return(arch_ftrace_get_regs(fregs))
> > +#define ftrace_regs_query_register_offset(name) \
> > +	regs_query_register_offset(name)
> > +
> > +#endif /* HAVE_ARCH_FTRACE_REGS */
> > +
> > +#endif /* _LINUX_FTRACE_TYPES_H */  
> 
> Ditto.
> 
> Others looks good to me.
> 
> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Thanks,

I'll send a v2 with this update.

-- Steve