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[PATCH v12 3/5] rust: samples: add tracepoint to Rust sample

Alice Ryhl posted 5 patches 3 weeks, 4 days ago
[PATCH v12 3/5] rust: samples: add tracepoint to Rust sample
Posted by Alice Ryhl 3 weeks, 4 days ago 
This updates the Rust printing sample to invoke a tracepoint. This
ensures that we have a user in-tree from the get-go even though the
patch is being merged before its real user.

Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
---
 MAINTAINERS                        |  1 +
 include/trace/events/rust_sample.h | 31 +++++++++++++++++++++++++++++++
 rust/bindings/bindings_helper.h    |  1 +
 samples/rust/Makefile              |  3 ++-
 samples/rust/rust_print.rs         | 18 ++++++++++++++++++
 samples/rust/rust_print_events.c   |  8 ++++++++
 6 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index a097afd76ded..a9b71411d77a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20223,6 +20223,7 @@ C:	zulip://rust-for-linux.zulipchat.com
 P:	https://rust-for-linux.com/contributing
 T:	git https://github.com/Rust-for-Linux/linux.git rust-next
 F:	Documentation/rust/
+F:	include/trace/events/rust_sample.h
 F:	rust/
 F:	samples/rust/
 F:	scripts/*rust*
diff --git a/include/trace/events/rust_sample.h b/include/trace/events/rust_sample.h
new file mode 100644
index 000000000000..dbc80ca2e465
--- /dev/null
+++ b/include/trace/events/rust_sample.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Tracepoints for `samples/rust/rust_print.rs`.
+ *
+ * Copyright (C) 2024 Google, Inc.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM rust_sample
+
+#if !defined(_RUST_SAMPLE_TRACE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _RUST_SAMPLE_TRACE_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(rust_sample_loaded,
+	TP_PROTO(int magic_number),
+	TP_ARGS(magic_number),
+	TP_STRUCT__entry(
+		__field(int, magic_number)
+	),
+	TP_fast_assign(
+		__entry->magic_number = magic_number;
+	),
+	TP_printk("magic=%d", __entry->magic_number)
+);
+
+#endif /* _RUST_SAMPLE_TRACE_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
index 752572e638a6..b072c197ce9e 100644
--- a/rust/bindings/bindings_helper.h
+++ b/rust/bindings/bindings_helper.h
@@ -23,6 +23,7 @@
 #include <linux/tracepoint.h>
 #include <linux/wait.h>
 #include <linux/workqueue.h>
+#include <trace/events/rust_sample.h>
 
 /* `bindgen` gets confused at certain things. */
 const size_t RUST_CONST_HELPER_ARCH_SLAB_MINALIGN = ARCH_SLAB_MINALIGN;
diff --git a/samples/rust/Makefile b/samples/rust/Makefile
index 03086dabbea4..f29280ec4820 100644
--- a/samples/rust/Makefile
+++ b/samples/rust/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
+ccflags-y += -I$(src)				# needed for trace events
 
 obj-$(CONFIG_SAMPLE_RUST_MINIMAL)		+= rust_minimal.o
-obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o
+obj-$(CONFIG_SAMPLE_RUST_PRINT)			+= rust_print.o rust_print_events.o
 
 subdir-$(CONFIG_SAMPLE_RUST_HOSTPROGS)		+= hostprogs
diff --git a/samples/rust/rust_print.rs b/samples/rust/rust_print.rs
index 6eabb0d79ea3..6d14b08cac1c 100644
--- a/samples/rust/rust_print.rs
+++ b/samples/rust/rust_print.rs
@@ -69,6 +69,8 @@ fn init(_module: &'static ThisModule) -> Result<Self> {
 
         arc_print()?;
 
+        trace::trace_rust_sample_loaded(42);
+
         Ok(RustPrint)
     }
 }
@@ -78,3 +80,19 @@ fn drop(&mut self) {
         pr_info!("Rust printing macros sample (exit)\n");
     }
 }
+
+mod trace {
+    use core::ffi::c_int;
+
+    kernel::declare_trace! {
+        /// # Safety
+        ///
+        /// Always safe to call.
+        unsafe fn rust_sample_loaded(magic: c_int);
+    }
+
+    pub(crate) fn trace_rust_sample_loaded(magic: i32) {
+        // SAFETY: Always safe to call.
+        unsafe { rust_sample_loaded(magic as c_int) }
+    }
+}
diff --git a/samples/rust/rust_print_events.c b/samples/rust/rust_print_events.c
new file mode 100644
index 000000000000..a9169ff0edf1
--- /dev/null
+++ b/samples/rust/rust_print_events.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2024 Google LLC
+ */
+
+#define CREATE_TRACE_POINTS
+#define CREATE_RUST_TRACE_POINTS
+#include <trace/events/rust_sample.h>

-- 
2.47.0.163.g1226f6d8fa-goog
Re: [PATCH v12 3/5] rust: samples: add tracepoint to Rust sample
Posted by kernel test robot 3 weeks, 1 day ago 
Hi Alice,

kernel test robot noticed the following build errors:

[auto build test ERROR on eb887c4567d1b0e7684c026fe7df44afa96589e6]

url:    https://github.com/intel-lab-lkp/linux/commits/Alice-Ryhl/rust-add-static_branch_unlikely-for-static_key_false/20241031-000709
base:   eb887c4567d1b0e7684c026fe7df44afa96589e6
patch link:    https://lore.kernel.org/r/20241030-tracepoint-v12-3-eec7f0f8ad22%40google.com
patch subject: [PATCH v12 3/5] rust: samples: add tracepoint to Rust sample
config: x86_64-randconfig-103-20241101 (https://download.01.org/0day-ci/archive/20241102/202411021421.jZ0FSDq6-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241102/202411021421.jZ0FSDq6-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202411021421.jZ0FSDq6-lkp@intel.com/

All errors (new ones prefixed by >>):

>> error[E0425]: cannot find value `__tracepoint_rust_sample_loaded` in crate `$crate::bindings`
   --> samples/rust/rust_print.rs:87:5
   |
   87 | /     kernel::declare_trace! {
   88 | |         /// # Safety
   89 | |         ///
   90 | |         /// Always safe to call.
   91 | |         unsafe fn rust_sample_loaded(magic: c_int);
   92 | |     }
   | |_____^ not found in `$crate::bindings`
   |
   = note: this error originates in the macro `kernel::declare_trace` (in Nightly builds, run with -Z macro-backtrace for more info)
--
>> error[E0425]: cannot find function `rust_do_trace_rust_sample_loaded` in crate `$crate::bindings`
   --> samples/rust/rust_print.rs:87:5
   |
   87 | /     kernel::declare_trace! {
   88 | |         /// # Safety
   89 | |         ///
   90 | |         /// Always safe to call.
   91 | |         unsafe fn rust_sample_loaded(magic: c_int);
   92 | |     }
   | |_____^ not found in `$crate::bindings`
   |
   = note: this error originates in the macro `kernel::declare_trace` (in Nightly builds, run with -Z macro-backtrace for more info)

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Re: [PATCH v12 3/5] rust: samples: add tracepoint to Rust sample
Posted by Alice Ryhl 2 weeks, 6 days ago 
On Sat, Nov 2, 2024 at 8:08 AM kernel test robot <lkp@intel.com> wrote:
>
> Hi Alice,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on eb887c4567d1b0e7684c026fe7df44afa96589e6]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Alice-Ryhl/rust-add-static_branch_unlikely-for-static_key_false/20241031-000709
> base:   eb887c4567d1b0e7684c026fe7df44afa96589e6
> patch link:    https://lore.kernel.org/r/20241030-tracepoint-v12-3-eec7f0f8ad22%40google.com
> patch subject: [PATCH v12 3/5] rust: samples: add tracepoint to Rust sample
> config: x86_64-randconfig-103-20241101 (https://download.01.org/0day-ci/archive/20241102/202411021421.jZ0FSDq6-lkp@intel.com/config)
> compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241102/202411021421.jZ0FSDq6-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202411021421.jZ0FSDq6-lkp@intel.com/
>
> All errors (new ones prefixed by >>):
>
> >> error[E0425]: cannot find value `__tracepoint_rust_sample_loaded` in crate `$crate::bindings`
>    --> samples/rust/rust_print.rs:87:5
>    |
>    87 | /     kernel::declare_trace! {
>    88 | |         /// # Safety
>    89 | |         ///
>    90 | |         /// Always safe to call.
>    91 | |         unsafe fn rust_sample_loaded(magic: c_int);
>    92 | |     }
>    | |_____^ not found in `$crate::bindings`
>    |
>    = note: this error originates in the macro `kernel::declare_trace` (in Nightly builds, run with -Z macro-backtrace for more info)
> --
> >> error[E0425]: cannot find function `rust_do_trace_rust_sample_loaded` in crate `$crate::bindings`
>    --> samples/rust/rust_print.rs:87:5
>    |
>    87 | /     kernel::declare_trace! {
>    88 | |         /// # Safety
>    89 | |         ///
>    90 | |         /// Always safe to call.
>    91 | |         unsafe fn rust_sample_loaded(magic: c_int);
>    92 | |     }
>    | |_____^ not found in `$crate::bindings`
>    |
>    = note: this error originates in the macro `kernel::declare_trace` (in Nightly builds, run with -Z macro-backtrace for more info)

This bot is using a buggy bindgen. Please see
https://lore.kernel.org/all/20241030-bindgen-libclang-warn-v1-1-3a7ba9fedcfe@google.com/
which was also mentioned in the cover letter.

Alice

Patchew 2.1-devel-b67e4c2

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