From patchwork Fri Aug 16 11:07:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alice Ryhl X-Patchwork-Id: 13765982 Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F1F0319E7F5 for ; Fri, 16 Aug 2024 11:08:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723806506; cv=none; b=jGJdkMCJ/CV/ezgR7LWK3YK2SLg+QFmls+yJwZOFf/pUTruHeLmEo4WepiXCVnwgoIJ3HXr78g5EJ4EiiLO0oOefWzT3kKjb9u0oWKKgyFZNNGXBGUzg/Ybg/GfwXIQgja9hKeAUzmlOHd/ZvtXfnE6xFeCFSoBMdJGPmORhSoM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723806506; c=relaxed/simple; bh=mbr+t2kdtAR0gaGGgahPyE7BcbfXEyne0mHE/YfAoMM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=kkoy80qv6/D5mwFX67CQZ+5Iawh0zenvwqXNUH9OWYv7ZLEyMeQ0JTxvcXWcXLWllcwKmmrF/IaPiqzo4P1IcVzSUa+zsfKfRh0u3PDjoDW1ZudhCfpgIyFa/EVaDx/iivVpK0Wy79Hm1tBHKu6d9/+ol/lGTpdfa6Muw6keIV0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=l8+KafJA; arc=none smtp.client-ip=209.85.128.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="l8+KafJA" Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-650ab31aabdso27410857b3.3 for ; Fri, 16 Aug 2024 04:08:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1723806504; x=1724411304; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=f8cDHUaReumSMCOwyu04+mqYJDxHlzEMGiEzz4YHS0I=; b=l8+KafJAX+BuLRXc8kBvwwvZXecSAxT/zREOn480lVeSQ8CObESlFTs1K7PV6OdxC6 OeVbfXxMl+ML2QqpvHuW3mTEdel+LhH4C8khQeu/crBC1qg94dxr/oGlhemrxKSr0Alp YD0lVOXVFzBDP2hFMpZ02tz1Q7uW960P69PmAWiyapH4kYZa8BnJHns7ARRdP0vb35M1 dRDLBwt8vQTura0WnKKORU2nKXjvC/4AsIhLKNmbGN/+Aj+5uu/mRg7EyIM9TiVo885B QvGKLGkx2aez2b1hUKFzBGe8/3Feaus0yj789i61wHR4/l6BxbIvHOg/Dr/wj6zjFKY3 WB2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723806504; x=1724411304; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=f8cDHUaReumSMCOwyu04+mqYJDxHlzEMGiEzz4YHS0I=; b=WxWbZ426GWMJcpMu9Jn/5bQ42PfnjWbeEIBIZnvUlxxxMUSPQzQxidBA6z+rOurr8n TacHDqTbvFQCF6sZJQGklt2v+ec/s/8hArIhBjJ1QnVwz2+gRJkAfkuYiJ96xL3ruD28 yGMZ/EWgcFOF8bdtDmX5Dhad0JzIjKJehqltLsdo5AlcHBQVGsPQF/NVWYpAF4GAJLzo NJW+aeTC1OZExiyU0sCcSD76+XG1C7+Ij62VvvUKRwkuwn0wvc7HG1JqcGBV4B04jYmR msdTyWyFkEBqArKTlIPWEDFT0ptGuC4tTKgWzy6yqruZICNl5PtQrJMd2aBAp4p1mzq+ 6Z9A== X-Gm-Message-State: AOJu0YwYDpUIiokKJEPwIlRQRsxf0tYbedx+8hwDBTQsvpnSRT6TplDe aazTEEBYtvBTnGDTzLuESRgqFBSbA+hM86nnatZKOYYUt43O2VSKVfjSVb1hLPN7DJbXqZtiVDy mvzJYowo5YofYuA== X-Google-Smtp-Source: AGHT+IHH8lqqbhavxoP9Vhrf4pidZ6/IQffeAAO7T7zZPPnk0pGCI+CN5pb9fvzDZryrjR97LYdyHBHJxNwBKX8= X-Received: from aliceryhl.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:35bd]) (user=aliceryhl job=sendgmr) by 2002:a05:690c:7281:b0:68e:8de6:618b with SMTP id 00721157ae682-6b1b72af093mr1195957b3.2.1723806503892; Fri, 16 Aug 2024 04:08:23 -0700 (PDT) Date: Fri, 16 Aug 2024 11:07:39 +0000 In-Reply-To: <20240816-tracepoint-v7-0-d609b916b819@google.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240816-tracepoint-v7-0-d609b916b819@google.com> X-Developer-Key: i=aliceryhl@google.com; a=openpgp; fpr=49F6C1FAA74960F43A5B86A1EE7A392FDE96209F X-Developer-Signature: v=1; a=openpgp-sha256; l=6866; i=aliceryhl@google.com; h=from:subject:message-id; bh=mbr+t2kdtAR0gaGGgahPyE7BcbfXEyne0mHE/YfAoMM=; b=owEBbQKS/ZANAwAKAQRYvu5YxjlGAcsmYgBmvzMdw+Rmuw1TZAV/JDQBRFjlFdszXt+U1btzR gGP87RjnbOJAjMEAAEKAB0WIQSDkqKUTWQHCvFIvbIEWL7uWMY5RgUCZr8zHQAKCRAEWL7uWMY5 Rn4jEACX97xcITEZga8P+ngCFqMoTIOKDVCNcrHpYF1tLAFZDcR9+ZyrndHeCvZol3Ll5q11q18 kd9BSXFiKXLVSYTY+FqEDInWIquj6oGSWuz0uoyTkHvbQGQ0Tbc/EdWGx5hU11NcUaGjrsxCGqb 06bAm9AYahSnbpMI87qadxYJ5tjW/eNhxjQU0S/BxReS+m3/rcmLwrpxQKI/HD7FbdSg69OUEnk sqJeeZQVy2CyHsoDWpO2TBYkOpi/zuprwTO3+tjl/9fz/CRV4DfcS5CseZnOOiOTHAYSuUGnT8D gf12tNcy2PklPmTCrrpsX9w5hfCPU1NR1/7Hg0wMrkBiBZMY35RM5ScaiPJ5joj/eWQHLDbvrzR rGWR3OgLMb91wNGe6mXEe3CarzS9pJKXQu5yyIWcHUYtWYHcKNjF4D3BJnG93RDDkAz4ctOLcuz uO0S2+nNx56UrOP7QRbqIu1cKaiGl2M5neW1y6n1Bb/n2cH0PYp5xaeC9sQa+ecyzw3Kj1EaBLG MSvgcTS9T5/R/wB5AouMqn8j7gVWaz4asQMshftP+tAgmrCFyi7msOEYSvnhTGx2BlNIJCgFt4E gOqQJNjdL+HUbc8+sPDOr9q5HGaDikRjs7pZy3nxtLy4Up0Anr58vd4LLaUoxA+gBe6up974yfC CQrWHCnO/UBYrbw== X-Mailer: b4 0.13.0 Message-ID: <20240816-tracepoint-v7-2-d609b916b819@google.com> Subject: [PATCH v7 2/5] rust: add tracepoint support From: Alice Ryhl To: Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Peter Zijlstra , Josh Poimboeuf , Jason Baron , Ard Biesheuvel , Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " , Benno Lossin , Andreas Hindborg Cc: linux-trace-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, Arnd Bergmann , linux-arch@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Sean Christopherson , Uros Bizjak , Catalin Marinas , Will Deacon , Marc Zyngier , Oliver Upton , Mark Rutland , Ryan Roberts , Fuad Tabba , linux-arm-kernel@lists.infradead.org, Paul Walmsley , Palmer Dabbelt , Albert Ou , Anup Patel , Andrew Jones , Alexandre Ghiti , Conor Dooley , Samuel Holland , linux-riscv@lists.infradead.org, Huacai Chen , WANG Xuerui , Bibo Mao , Tiezhu Yang , Andrew Morton , Tianrui Zhao , loongarch@lists.linux.dev, Alice Ryhl , Carlos Llamas 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. Instead of calling __DO_TRACE directly, the exported rust_do_trace_ function calls an inline helper function. This is because the `cond` argument does not exist at the callsite of DEFINE_RUST_DO_TRACE. __DECLARE_TRACE always emits an inline static and an extern declaration that is only used when CREATE_RUST_TRACE_POINTS is set. These should not end up in the final binary so it is not a problem that they sometimes are emitted without a user. Reviewed-by: Carlos Llamas Reviewed-by: Gary Guo Signed-off-by: Alice Ryhl --- include/linux/tracepoint.h | 22 +++++++++++++++++- include/trace/define_trace.h | 12 ++++++++++ rust/bindings/bindings_helper.h | 1 + rust/kernel/lib.rs | 1 + rust/kernel/tracepoint.rs | 49 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 84 insertions(+), 1 deletion(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 6be396bb4297..5042ca588e41 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -237,6 +237,18 @@ 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(name, proto, args) \ + notrace void rust_do_trace_##name(proto) \ + { \ + __rust_do_trace_##name(args); \ + } + /* * Make sure the alignment of the structure in the __tracepoints section will * not add unwanted padding between the beginning of the section and the @@ -252,6 +264,13 @@ 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 __rust_do_trace_##name(proto) \ + { \ + __DO_TRACE(name, \ + TP_ARGS(args), \ + TP_CONDITION(cond), 0); \ + } \ static inline void trace_##name(proto) \ { \ if (static_key_false(&__tracepoint_##name.key)) \ @@ -336,7 +355,8 @@ 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..8159294c2041 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(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 8fd092e1b809..fc6f94729789 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -20,6 +20,7 @@ #include #include #include +#include #include #include diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 91af9f75d121..d00a44b000b6 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -51,6 +51,7 @@ pub mod sync; pub mod task; pub mod time; +pub mod tracepoint; pub mod types; pub mod uaccess; pub mod workqueue; diff --git a/rust/kernel/tracepoint.rs b/rust/kernel/tracepoint.rs new file mode 100644 index 000000000000..cf2d9ad15912 --- /dev/null +++ b/rust/kernel/tracepoint.rs @@ -0,0 +1,49 @@ +// SPDX-License-Identifier: GPL-2.0 + +// Copyright (C) 2024 Google LLC. + +//! Logic for tracepoints. + +/// Declare the Rust entry point for a tracepoint. +/// +/// This macro generates an unsafe function that calls into C, and its safety requirements will be +/// whatever the relevant C code requires. To document these safety requirements, you may add +/// doc-comments when invoking the macro. +#[macro_export] +macro_rules! declare_trace { + ($($(#[$attr:meta])* $pub:vis unsafe fn $name:ident($($argname:ident : $argtyp:ty),* $(,)?);)*) => {$( + $( #[$attr] )* + #[inline(always)] + $pub unsafe fn $name($($argname : $argtyp),*) { + #[cfg(CONFIG_TRACEPOINTS)] + { + // SAFETY: It's always okay to query the static key for a tracepoint. + let should_trace = unsafe { + $crate::macros::paste! { + $crate::jump_label::static_key_false!( + $crate::bindings::[< __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 { $crate::bindings::[< 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;