From patchwork Tue Oct 15 13:14:56 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alice Ryhl X-Patchwork-Id: 13836403 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7273FD2169C for ; Tue, 15 Oct 2024 13:17:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:From:Subject:Message-ID: References:Mime-Version:In-Reply-To:Date:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=gfE7ZShE5ohktZ/M4YwIz7ImaV3NbvLnf2y1kLbWEX8=; b=JsAdYeznmmWxs1mC/uOsWxqr0I FNFnUD5GdfnTT8MeOMy55EEwI31hG0m9+1wwm8xAOWhvIXuMZi4BLTEmYC7J41bb6YapWyhl0jOSq 7n07goTJnNkNv2WAll2lWwLv+SvOf6Z32IwOacWE5zwvwE1IB2pXbWdUOxPJ0NSQobFurymxRXMRx tXuC9yblcf2u460EsD6NR7ldl2RSB+VHLYMsmQyKVbnLSJkl3Yhw+PsbVH/MnB0L/yK593K24THDv qzJesslxRBYhM1JowKfrnT8b4woTlhovlkzhnw5XmcRwxA6Vxg4DYvVPOs5lvrArXnpRePN8csOip 0Ku3iI2g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t0hQ7-00000008JYI-49Ri; Tue, 15 Oct 2024 13:17:03 +0000 Received: from mail-yw1-x1149.google.com ([2607:f8b0:4864:20::1149]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t0hOc-00000008Iua-1ImS for linux-riscv@lists.infradead.org; Tue, 15 Oct 2024 13:15:32 +0000 Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-6e3245ed6b8so76714017b3.0 for ; Tue, 15 Oct 2024 06:15:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1728998129; x=1729602929; darn=lists.infradead.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=Qvgr+n6BCCNgQWUs70Ofe8Bn1gFUAza68YbSHBnfTLY=; b=cLbPiQM8WjQnVNS1R1QE2dQos+y8C82sAuAsNH0qzGomShc468k9gSLEcrUQbK31R7 ke/8S8PFnFwbyd+u/Pdyee/R+Hq48a7c9EeLDz58plgxinHkc/Xgr5Q1RpD71qkvD8jJ N23qx5BbEU1rmCPYOZEV+OlsIlORtHab8wMn2SgPxeW4s8eEdO5TUgObRHZy3gDZP/+1 cYG6M3AO0WYtG2Mmumk4PiEnFymV0pS1xncT2NejGJei8ljTK4JGQA6pb+z8e1CX6KBg IGecEI0yD9RW7APHpR/Ml4uIq2VADEBvLxBO2J+d0t0raqBTO62jhq1fuQqOKbbTtGx1 mEYQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728998129; x=1729602929; 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=Qvgr+n6BCCNgQWUs70Ofe8Bn1gFUAza68YbSHBnfTLY=; b=vRBePgVVxtxsu4CKTZij6XVlQrX4J97Ga0/4u9Evcpwr6WuuGKulPZcI/ASGN04R4N pG0sz/F8KPuyUTWg6XQ1y4QAsGSoLhM9dba0l6K7GOfuSyiya/wiZJzFZqZ107lj3d7w r/nviHGuYH+jPzp2r6Z9UAriyPOeBRYlAZ2c3M8u6HfRsgkLf8z7kAo49VQG/C8vnPYX fMw+4o+tb+imK5Qd6Gu9ts0wNJRBxw2ElU6JXKnhtwUOhx5JrNKmK63HxjYJfV8oRkgd g48QRcKqTEoiksdlFmw/s8z5e2QT2ECUl9xjbFj1E5cC0wY5kZWDMa6qGJcw8ZgoWa6U RFHQ== X-Forwarded-Encrypted: i=1; AJvYcCUyT8wC8kf8nH56DjSXgqFsfj3w81MmVvcE6L/H50+Jm8BSQkHNZC8ObJL2gdGm69eBOYQCvEqkmgs7ww==@lists.infradead.org X-Gm-Message-State: AOJu0Yy/OHwc8fCA9zDjlvrl7WuNEACfSBMrrg2oOdSbDb2HQ7WXFQjz BGH9g2wcaTg9t2hpwXGAl9ipZW/0/IGdYxRYlpAFvP7JKA7zTryRax84FdMH/D80ZsZjD9iWwdc cMjbuTL/36fwvuA== X-Google-Smtp-Source: AGHT+IH2aipjAuwBfMr6lWsvCGRlG0PFPRVftjjOVqprnLHjHCiydmMQVYwQADN3PA15UjoohsjIs5Ot+NwtIxo= X-Received: from aliceryhl.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:35bd]) (user=aliceryhl job=sendgmr) by 2002:a25:d0c3:0:b0:e28:e7b0:ba89 with SMTP id 3f1490d57ef6-e29782d5437mr91276.4.1728998128548; Tue, 15 Oct 2024 06:15:28 -0700 (PDT) Date: Tue, 15 Oct 2024 13:14:56 +0000 In-Reply-To: <20241015-tracepoint-v11-0-cceb65820089@google.com> Mime-Version: 1.0 References: <20241015-tracepoint-v11-0-cceb65820089@google.com> X-Developer-Key: i=aliceryhl@google.com; a=openpgp; fpr=49F6C1FAA74960F43A5B86A1EE7A392FDE96209F X-Developer-Signature: v=1; a=openpgp-sha256; l=7835; i=aliceryhl@google.com; h=from:subject:message-id; bh=GMLTcVVdmPl90l3vR60nLHEg+YV0m6WjZcRDkYDuaVU=; b=owEBbQKS/ZANAwAKAQRYvu5YxjlGAcsmYgBnDmrmpScs98atPErvy3Y3eDID5B6ICKiw+WaX3 dd0B5/EcSWJAjMEAAEKAB0WIQSDkqKUTWQHCvFIvbIEWL7uWMY5RgUCZw5q5gAKCRAEWL7uWMY5 RnB9D/0UA1WuJngFq3RXVOyFVknNYlK5cilfOkXWXwOcoiwZMU6kVx9cPG+1OwA5DfxXhvyvCjv 6oOSS+gaOV2wBrhGCz5bRclAN3LDMDFwjwfcDdlc7z7KUpJ44fWXi3FHcSvB6hXUDLSXzC361GB 3rESJnwE7beWBsmzOFPkHdvjSvaXsil0sseYstVZoHs4bVFT4gVRtD/0+64P4CkyDJQ4kpxYK3Z he3RpQ1akkRuff0JmCbd50c3smDhO/nHhKal/J1Rx05JeSyaF9bV6+sTGuiiL+IwWyY+MSvCFTu GuARc5Cx9bRPG1/U7+V+09IQgApXpjHrAGWXocYntPmyRcLIhNmewXdu0SJJAOKrLqC3/o4m0wW UtRk9qxO5wIQs7+cBeW/kG+CVkK7H+BhoGizw/mC7a7GNCLJ+8k7t8Mw2u9ghRyQqRxXYaD8zlX BXJ6Z05N+pCHBpOIZGjRBXyDWXeYkbk74RTjbXM7QEYoc++5N2QaeRr+hJxTQN7+h+JxCJlGHR/ mjvDwccIlqvEPDzuhE4mB327nc10KvLuu6+uCl18YOB5t1vXd+91vLIypq8hyEGDff2zQ29Hyg6 vzBYqAaxefiiAWIN9sZnUDVQzrzgpqzWwKCXWjog113vaO4y4/2J/8aTDfiuP0dChPs3DuTjwkR sgK5iD1yMaqp1zw== X-Mailer: b4 0.13.0 Message-ID: <20241015-tracepoint-v11-2-cceb65820089@google.com> Subject: [PATCH v11 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241015_061530_470053_5C33EA82 X-CRM114-Status: GOOD ( 27.58 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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 Reviewed-by: Boqun Feng Signed-off-by: Alice Ryhl --- include/linux/tracepoint.h | 28 ++++++++++++++++++++++- 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, 90 insertions(+), 1 deletion(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 0dc67fad706c..84c4924e499f 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -225,6 +225,18 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) preempt_enable_notrace(); \ } while (0) +/* + * 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 @@ -240,6 +252,7 @@ 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 int \ register_trace_##name(void (*probe)(data_proto), void *data) \ { \ @@ -271,6 +284,12 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #define __DECLARE_TRACE(name, proto, args, cond, data_proto) \ __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), cond, PARAMS(data_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_branch_unlikely(&__tracepoint_##name.key)) \ @@ -285,6 +304,12 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #define __DECLARE_TRACE_SYSCALL(name, proto, args, cond, data_proto) \ __DECLARE_TRACE_COMMON(name, PARAMS(proto), PARAMS(args), cond, PARAMS(data_proto)) \ + static inline void __rust_do_trace_##name(proto) \ + { \ + __DO_TRACE(name, \ + TP_ARGS(args), \ + TP_CONDITION(cond), 1); \ + } \ static inline void trace_##name(proto) \ { \ if (static_branch_unlikely(&__tracepoint_##name.key)) \ @@ -339,7 +364,8 @@ 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 ff5fa17a6259..0557626b6f6a 100644 --- a/include/trace/define_trace.h +++ b/include/trace/define_trace.h @@ -76,6 +76,13 @@ #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 @@ -134,6 +141,11 @@ # 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 e0846e7e93e6..752572e638a6 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 708ff817ccc3..55f81f49024e 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -54,6 +54,7 @@ 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..c6e80aa99e8e --- /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_branch_unlikely!( + $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;