| Message ID | 20240621-tracepoint-v3-2-9e44eeea2b85@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Tracepoints and static branch in Rust | expand |
On Fri, Jun 21, 2024 at 12:35 PM 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> > --- > include/linux/tracepoint.h | 18 +++++++++++++++- > include/trace/define_trace.h | 7 ++++++ > rust/bindings/bindings_helper.h | 1 + > rust/kernel/lib.rs | 1 + > rust/kernel/tracepoint.rs | 47 +++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 73 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); \ > + } > + > /* > * 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..b47cc036acba 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 > > diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h Hmm, I tried using the support where I have both events and hooks: #define CREATE_TRACE_POINTS #define CREATE_RUST_TRACE_POINTS #include <trace/hooks/rust_binder.h> #include <trace/events/rust_binder.h> But it's not really working. Initially I thought that it's because I need to undef DEFINE_RUST_DO_TRACE at the end of this file, but even when I added that, I still get this error: error: redefinition of 'str__rust_binder__trace_system_name' Is the Rust support missing something, or is the answer just that you can't have two files of the same name like this? Or am I doing something else wrong? Alice
On Fri, Jun 21, 2024 at 02:52:10PM +0200, Alice Ryhl wrote: [...] > > Hmm, I tried using the support where I have both events and hooks: > > #define CREATE_TRACE_POINTS > #define CREATE_RUST_TRACE_POINTS > #include <trace/hooks/rust_binder.h> > #include <trace/events/rust_binder.h> > > But it's not really working. Initially I thought that it's because I > need to undef DEFINE_RUST_DO_TRACE at the end of this file, but even > when I added that, I still get this error: > > error: redefinition of 'str__rust_binder__trace_system_name' > > Is the Rust support missing something, or is the answer just that you > can't have two files of the same name like this? Or am I doing > something else wrong? > Because your hooks/rust_binder.h and events/rust_binder.h use the same TRACE_SYSTEM name? Could you try something like: #define TRACE_SYSTEM rust_binder_hook in your hooks/rust_binder.h? Regards, Boqun > Alice
On Tue, Jun 25, 2024 at 8:11 PM Boqun Feng <boqun.feng@gmail.com> wrote: > > On Fri, Jun 21, 2024 at 02:52:10PM +0200, Alice Ryhl wrote: > [...] > > > > Hmm, I tried using the support where I have both events and hooks: > > > > #define CREATE_TRACE_POINTS > > #define CREATE_RUST_TRACE_POINTS > > #include <trace/hooks/rust_binder.h> > > #include <trace/events/rust_binder.h> > > > > But it's not really working. Initially I thought that it's because I > > need to undef DEFINE_RUST_DO_TRACE at the end of this file, but even > > when I added that, I still get this error: > > > > error: redefinition of 'str__rust_binder__trace_system_name' > > > > Is the Rust support missing something, or is the answer just that you > > can't have two files of the same name like this? Or am I doing > > something else wrong? > > > > Because your hooks/rust_binder.h and events/rust_binder.h use the same > TRACE_SYSTEM name? Could you try something like: > > #define TRACE_SYSTEM rust_binder_hook > > in your hooks/rust_binder.h? I was able to get it to work by moving the includes into two different .c files. I don't think changing TRACE_SYSTEM works because it must match the filename. Alice
On Wed, 26 Jun 2024 10:48:23 +0200 Alice Ryhl <aliceryhl@google.com> wrote: > > > > Because your hooks/rust_binder.h and events/rust_binder.h use the same > > TRACE_SYSTEM name? Could you try something like: > > > > #define TRACE_SYSTEM rust_binder_hook > > > > in your hooks/rust_binder.h? > > I was able to get it to work by moving the includes into two different > .c files. I don't think changing TRACE_SYSTEM works because it must > match the filename. Try to use: #define TRACE_SYSTEM_VAR rust_binder_hook_other_name in one. Then that is used as the variable for that file. -- Steve
On Wed, Jun 26, 2024 at 8:43 PM Steven Rostedt <rostedt@goodmis.org> wrote: > > On Wed, 26 Jun 2024 10:48:23 +0200 > Alice Ryhl <aliceryhl@google.com> wrote: > > > > > > > Because your hooks/rust_binder.h and events/rust_binder.h use the same > > > TRACE_SYSTEM name? Could you try something like: > > > > > > #define TRACE_SYSTEM rust_binder_hook > > > > > > in your hooks/rust_binder.h? > > > > I was able to get it to work by moving the includes into two different > > .c files. I don't think changing TRACE_SYSTEM works because it must > > match the filename. > > Try to use: > > #define TRACE_SYSTEM_VAR rust_binder_hook_other_name > > in one. Then that is used as the variable for that file. Thanks. I also made a change to restore the value of DEFINE_RUST_DO_TRACE after define_trace.h Alice
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..b47cc036acba 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 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 a0be9544996d..96f8f11c51f2 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -45,6 +45,7 @@ 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 | 7 ++++++ rust/bindings/bindings_helper.h | 1 + rust/kernel/lib.rs | 1 + rust/kernel/tracepoint.rs | 47 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 73 insertions(+), 1 deletion(-)