| Message ID | 20240628-tracepoint-v4-2-353d523a9c15@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Tracepoints and static branch in Rust | expand |
On Fri, Jun 28, 2024 at 01:23:32PM +0000, Alice Ryhl wrote: > Make it possible to have Rust code call into tracepoints defined by C > code. It is still required that the tracepoint is declared in a C > header, and that this header is included in the input to bindgen. > > Signed-off-by: Alice Ryhl <aliceryhl@google.com> > --- > include/linux/tracepoint.h | 18 +++++++++++++++- > include/trace/define_trace.h | 12 +++++++++++ > rust/bindings/bindings_helper.h | 1 + > rust/kernel/lib.rs | 1 + > rust/kernel/tracepoint.rs | 47 +++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 78 insertions(+), 1 deletion(-) > > diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h > index 689b6d71590e..d82af4d77c9f 100644 > --- a/include/linux/tracepoint.h > +++ b/include/linux/tracepoint.h > @@ -238,6 +238,20 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) > #define __DECLARE_TRACE_RCU(name, proto, args, cond) > #endif > > +/* > + * Declare an exported function that Rust code can call to trigger this > + * tracepoint. This function does not include the static branch; that is done > + * in Rust to avoid a function call when the tracepoint is disabled. > + */ > +#define DEFINE_RUST_DO_TRACE(name, proto, args) > +#define DEFINE_RUST_DO_TRACE_REAL(name, proto, args) \ nit: IMO using a __* prefix would be a better option to describe the internal use of the macro instead of the _REAL suffix. Other than that, this patch looks good to me: Reviewed-by: Carlos Llamas <cmllamas@google.com>
On Fri, 28 Jun 2024 13:23:32 +0000 Alice Ryhl <aliceryhl@google.com> wrote: > Make it possible to have Rust code call into tracepoints defined by C > code. It is still required that the tracepoint is declared in a C > header, and that this header is included in the input to bindgen. > > Signed-off-by: Alice Ryhl <aliceryhl@google.com> The Rust part LGTM. Some comment about the C part. > --- > include/linux/tracepoint.h | 18 +++++++++++++++- > include/trace/define_trace.h | 12 +++++++++++ > rust/bindings/bindings_helper.h | 1 + > rust/kernel/lib.rs | 1 + > rust/kernel/tracepoint.rs | 47 +++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 78 insertions(+), 1 deletion(-) > > diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h > index 689b6d71590e..d82af4d77c9f 100644 > --- a/include/linux/tracepoint.h > +++ b/include/linux/tracepoint.h > @@ -238,6 +238,20 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) > #define __DECLARE_TRACE_RCU(name, proto, args, cond) > #endif > > +/* > + * Declare an exported function that Rust code can call to trigger this > + * tracepoint. This function does not include the static branch; that is done > + * in Rust to avoid a function call when the tracepoint is disabled. > + */ > +#define DEFINE_RUST_DO_TRACE(name, proto, args) > +#define DEFINE_RUST_DO_TRACE_REAL(name, proto, args) \ > + notrace void rust_do_trace_##name(proto) \ > + { \ > + __DO_TRACE(name, \ > + TP_ARGS(args), \ > + cpu_online(raw_smp_processor_id()), 0); \ I guess this doesn't support conditions. Currently the conditions are specified during declaration and not during definition. Would it make sense to have static inline void do_trace_##name(proto) { __DO_TRACE(name, TP_ARGS(args), TP_CONDITION(cond), 0); } in `__DECLARE_TRACE` and then simply call it in `rust_do_trace_##name`? > + } > + > /* > * Make sure the alignment of the structure in the __tracepoints section will > * not add unwanted padding between the beginning of the section and the > @@ -253,6 +267,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) > extern int __traceiter_##name(data_proto); \ > DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name); \ > extern struct tracepoint __tracepoint_##name; \ > + extern void rust_do_trace_##name(proto); \ > static inline void trace_##name(proto) \ > { \ > if (static_key_false(&__tracepoint_##name.key)) \ > @@ -337,7 +352,8 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) > void __probestub_##_name(void *__data, proto) \ > { \ > } \ > - DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); > + DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); \ > + DEFINE_RUST_DO_TRACE(_name, TP_PROTO(proto), TP_ARGS(args)) > > #define DEFINE_TRACE(name, proto, args) \ > DEFINE_TRACE_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args)); > diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h > index 00723935dcc7..08ed5ce63a96 100644 > --- a/include/trace/define_trace.h > +++ b/include/trace/define_trace.h > @@ -72,6 +72,13 @@ > #define DECLARE_TRACE(name, proto, args) \ > DEFINE_TRACE(name, PARAMS(proto), PARAMS(args)) > > +/* If requested, create helpers for calling these tracepoints from Rust. */ > +#ifdef CREATE_RUST_TRACE_POINTS > +#undef DEFINE_RUST_DO_TRACE > +#define DEFINE_RUST_DO_TRACE(name, proto, args) \ > + DEFINE_RUST_DO_TRACE_REAL(name, PARAMS(proto), PARAMS(args)) > +#endif > + > #undef TRACE_INCLUDE > #undef __TRACE_INCLUDE > > @@ -129,6 +136,11 @@ > # undef UNDEF_TRACE_INCLUDE_PATH > #endif > > +#ifdef CREATE_RUST_TRACE_POINTS > +# undef DEFINE_RUST_DO_TRACE > +# define DEFINE_RUST_DO_TRACE(name, proto, args) > +#endif > + > /* We may be processing more files */ > #define CREATE_TRACE_POINTS >
On Tue, 30 Jul 2024 11:35:27 +0100 Gary Guo <gary@garyguo.net> wrote: > > +/* > > + * Declare an exported function that Rust code can call to trigger this > > + * tracepoint. This function does not include the static branch; that is done > > + * in Rust to avoid a function call when the tracepoint is disabled. > > + */ > > +#define DEFINE_RUST_DO_TRACE(name, proto, args) > > +#define DEFINE_RUST_DO_TRACE_REAL(name, proto, args) \ > > + notrace void rust_do_trace_##name(proto) \ > > + { \ > > + __DO_TRACE(name, \ > > + TP_ARGS(args), \ > > + cpu_online(raw_smp_processor_id()), 0); \ > > I guess this doesn't support conditions. Currently the conditions are > specified during declaration and not during definition. > > Would it make sense to have > > static inline void do_trace_##name(proto) > { > __DO_TRACE(name, TP_ARGS(args), TP_CONDITION(cond), 0); But where is the "cond" passed in from? I guess in the future if you want to add conditions, you would then just add: #define DEFINE_RUST_DO_TRACE_REAL_CONDITION(name, proto, args, cond) \ notrace void rust_do_trace_##name(proto) \ { \ __DO_TRACE(name, \ TP_ARGS(args), \ cpu_online(raw_smp_processor_id()) && \ TP_CONDITION(cond), 0); \ -- Steve > } > > in `__DECLARE_TRACE` and then simply call it in `rust_do_trace_##name`? > > > + } > > + > > /*
On 28.06.24 15:23, Alice Ryhl wrote: > diff --git a/rust/kernel/tracepoint.rs b/rust/kernel/tracepoint.rs > new file mode 100644 > index 000000000000..1005f09e0330 > --- /dev/null > +++ b/rust/kernel/tracepoint.rs > @@ -0,0 +1,47 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +// Copyright (C) 2024 Google LLC. > + > +//! Logic for tracepoints. > + > +/// Declare the Rust entry point for a tracepoint. > +#[macro_export] > +macro_rules! declare_trace { > + ($($(#[$attr:meta])* $pub:vis fn $name:ident($($argname:ident : $argtyp:ty),* $(,)?);)*) => {$( > + $( #[$attr] )* > + #[inline(always)] > + $pub unsafe fn $name($($argname : $argtyp),*) { > + #[cfg(CONFIG_TRACEPOINTS)] > + { > + use $crate::bindings::*; Why is this needed, can't you put this into the invocation of `paste!`? ie `[< $crate::bindings::__tracepoint_ $name >]`? > + > + // SAFETY: It's always okay to query the static key for a tracepoint. > + let should_trace = unsafe { > + $crate::macros::paste! { > + $crate::static_key::static_key_false!( > + [< __tracepoint_ $name >], > + $crate::bindings::tracepoint, > + key > + ) > + } > + }; > + > + if should_trace { > + $crate::macros::paste! { > + // SAFETY: The caller guarantees that it is okay to call this tracepoint. Can you add this on the docs of `$name`? ie add a Safety section. The docs should still appear when creating them/when LSPs show them to you. --- Cheers, Benno > + unsafe { [< rust_do_trace_ $name >]($($argname),*) }; > + } > + } > + } > + > + #[cfg(not(CONFIG_TRACEPOINTS))] > + { > + // If tracepoints are disabled, insert a trivial use of each argument > + // to avoid unused argument warnings. > + $( let _unused = $argname; )* > + } > + } > + )*} > +} > + > +pub use declare_trace; > > -- > 2.45.2.803.g4e1b14247a-goog >
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 689b6d71590e..d82af4d77c9f 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -238,6 +238,20 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #define __DECLARE_TRACE_RCU(name, proto, args, cond) #endif +/* + * Declare an exported function that Rust code can call to trigger this + * tracepoint. This function does not include the static branch; that is done + * in Rust to avoid a function call when the tracepoint is disabled. + */ +#define DEFINE_RUST_DO_TRACE(name, proto, args) +#define DEFINE_RUST_DO_TRACE_REAL(name, proto, args) \ + notrace void rust_do_trace_##name(proto) \ + { \ + __DO_TRACE(name, \ + TP_ARGS(args), \ + cpu_online(raw_smp_processor_id()), 0); \ + } + /* * Make sure the alignment of the structure in the __tracepoints section will * not add unwanted padding between the beginning of the section and the @@ -253,6 +267,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) extern int __traceiter_##name(data_proto); \ DECLARE_STATIC_CALL(tp_func_##name, __traceiter_##name); \ extern struct tracepoint __tracepoint_##name; \ + extern void rust_do_trace_##name(proto); \ static inline void trace_##name(proto) \ { \ if (static_key_false(&__tracepoint_##name.key)) \ @@ -337,7 +352,8 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) void __probestub_##_name(void *__data, proto) \ { \ } \ - DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); + DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); \ + DEFINE_RUST_DO_TRACE(_name, TP_PROTO(proto), TP_ARGS(args)) #define DEFINE_TRACE(name, proto, args) \ DEFINE_TRACE_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args)); diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h index 00723935dcc7..08ed5ce63a96 100644 --- a/include/trace/define_trace.h +++ b/include/trace/define_trace.h @@ -72,6 +72,13 @@ #define DECLARE_TRACE(name, proto, args) \ DEFINE_TRACE(name, PARAMS(proto), PARAMS(args)) +/* If requested, create helpers for calling these tracepoints from Rust. */ +#ifdef CREATE_RUST_TRACE_POINTS +#undef DEFINE_RUST_DO_TRACE +#define DEFINE_RUST_DO_TRACE(name, proto, args) \ + DEFINE_RUST_DO_TRACE_REAL(name, PARAMS(proto), PARAMS(args)) +#endif + #undef TRACE_INCLUDE #undef __TRACE_INCLUDE @@ -129,6 +136,11 @@ # undef UNDEF_TRACE_INCLUDE_PATH #endif +#ifdef CREATE_RUST_TRACE_POINTS +# undef DEFINE_RUST_DO_TRACE +# define DEFINE_RUST_DO_TRACE(name, proto, args) +#endif + /* We may be processing more files */ #define CREATE_TRACE_POINTS diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index ddb5644d4fd9..d442f9ccfc2c 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -15,6 +15,7 @@ #include <linux/refcount.h> #include <linux/sched.h> #include <linux/slab.h> +#include <linux/tracepoint.h> #include <linux/wait.h> #include <linux/workqueue.h> diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index fffd4e1dd1c1..9ae90eb69020 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -46,6 +46,7 @@ pub mod sync; pub mod task; pub mod time; +pub mod tracepoint; pub mod types; pub mod workqueue; diff --git a/rust/kernel/tracepoint.rs b/rust/kernel/tracepoint.rs new file mode 100644 index 000000000000..1005f09e0330 --- /dev/null +++ b/rust/kernel/tracepoint.rs @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0 + +// Copyright (C) 2024 Google LLC. + +//! Logic for tracepoints. + +/// Declare the Rust entry point for a tracepoint. +#[macro_export] +macro_rules! declare_trace { + ($($(#[$attr:meta])* $pub:vis fn $name:ident($($argname:ident : $argtyp:ty),* $(,)?);)*) => {$( + $( #[$attr] )* + #[inline(always)] + $pub unsafe fn $name($($argname : $argtyp),*) { + #[cfg(CONFIG_TRACEPOINTS)] + { + use $crate::bindings::*; + + // SAFETY: It's always okay to query the static key for a tracepoint. + let should_trace = unsafe { + $crate::macros::paste! { + $crate::static_key::static_key_false!( + [< __tracepoint_ $name >], + $crate::bindings::tracepoint, + key + ) + } + }; + + if should_trace { + $crate::macros::paste! { + // SAFETY: The caller guarantees that it is okay to call this tracepoint. + unsafe { [< rust_do_trace_ $name >]($($argname),*) }; + } + } + } + + #[cfg(not(CONFIG_TRACEPOINTS))] + { + // If tracepoints are disabled, insert a trivial use of each argument + // to avoid unused argument warnings. + $( let _unused = $argname; )* + } + } + )*} +} + +pub use declare_trace;
Make it possible to have Rust code call into tracepoints defined by C code. It is still required that the tracepoint is declared in a C header, and that this header is included in the input to bindgen. Signed-off-by: Alice Ryhl <aliceryhl@google.com> --- include/linux/tracepoint.h | 18 +++++++++++++++- include/trace/define_trace.h | 12 +++++++++++ rust/bindings/bindings_helper.h | 1 + rust/kernel/lib.rs | 1 + rust/kernel/tracepoint.rs | 47 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 78 insertions(+), 1 deletion(-)