From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qv1-f53.google.com (mail-qv1-f53.google.com [209.85.219.53]) (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 5468C1B1D52 for ; Wed, 21 Aug 2024 17:08:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724260109; cv=none; b=fnwuzIi3NjppAF2kGSuJnyw9vyo/FR4C00R+e8M3GvED75IRrQexM4Yrr3tyLuSF0RPsMySN0dEvvgHjCsQTEV1eIoe+IxwQuh+WpC1AeqqT3G2oqMC5g58L+tMyIFDreKgyDOQeBQb9VzsEnD2XoRcbY6SY0RIbgIuCMdyHym4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724260109; c=relaxed/simple; bh=IuVDw/80YWYc4Tv7MyJ7dZ15Npf/cBodIg8N5LcldTM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mstqmHlUFFjxEhcFOUGntY1uCU6I6RSf5scSWgbOsLlokPp5F9FnKEfzA6YtCDCtqIrdf0RyzGi+3VV185DmQ7leRJp8pEKbWUDS5noARZMJhlzn2n8IRnA5FYHXcLI/x0zAYGS4Pi+RBDtGo/LrXjEUvcWV7S3ZHkNOuiQ7iAM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=Z9r/ct1X; arc=none smtp.client-ip=209.85.219.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Z9r/ct1X" Received: by mail-qv1-f53.google.com with SMTP id 6a1803df08f44-6bf8a662467so25208626d6.3 for ; Wed, 21 Aug 2024 10:08:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1724260106; x=1724864906; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:feedback-id:from:to:cc:subject:date :message-id:reply-to; bh=WItMaeY5hi8+K3FTWN8onrZqOVRFgwo42FK4ki6Up7k=; b=Z9r/ct1XoOPToY5pXv4mygjRKkAx/rzW/tOhsVShwzg+AWkOJOJgVz5HEdGH4m03Kv a14Dbwjm78Pxyx4iwygligY0QxX3ahFEVaMempoRlDIQHaXOYqWKejUwGdkHpLKFDPae C2UKzdaOjXypNwuRLBvSxN2Te7fvhRx4dt9Jsr4geWPWazpcMOpusmJklCkWVkJeXnyL YjgA5Usf6Q+en3iD2KtQwHc9y0+6nsVh86o9jIOPn/gK9VjQ0I0j+1hE6DDsD5vb7nTx 07dZTDVjYyq6fnsFE1HVzXlnji2vnoVAV8My8gC8fbY4V6AtGWsc29LVJD7PvzGnSFnC U/6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724260106; x=1724864906; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:feedback-id:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=WItMaeY5hi8+K3FTWN8onrZqOVRFgwo42FK4ki6Up7k=; b=F2CGqu7pusSYWzoBF7myMB/y0Z0B3z9oZZCoUyIh30qC77t2qIutKWIAVd3S27T8G2 rnH+G4IoJzfo7qqAFDDlv4TRd21xyyAInrtBGDKVwcTRqJZjWpGYaoxzF59W/wqXABYq mp2S8Fc/T3zX4oyMPN38FABaFjBwjw/DYi0qkK/NibigHiuNBQIEsZqyBlOYvOYJfjZY PygwwgWfRfmUZH8apYsMzyaOqv7noDd5Yvp8UQdcpAt1mzfltwS6nrDf2mzwm8HonhUx FN/SbPB83zAffU3Iv4AaaW8Cyhi5VpW8kQTTI/PJpTyBjLMUIhlgbDwB6rFLoBgHXfGZ FySA== X-Forwarded-Encrypted: i=1; AJvYcCULyMaN8zikfX9RnjItuGiXq0qwAdHwm1R1yK3dmSHYsFQTKKa+tquj35jvcDMiAuf3lqfWPfAE383XSuW86A==@vger.kernel.org X-Gm-Message-State: AOJu0YxRRq/JnqSpfI37qjMlGdQKaKUCPoX7IXZHHINYcM8FZb1XVLRg lSZY0i8wiQsmQOYSt9ZR5BkeMTQYxzt1Pmrf+mNdHySypEQBNmbj83Iazvw1 X-Google-Smtp-Source: AGHT+IFgzLEFazOLV2NiBDtpbCYcR89ibPWHYvZ2PcIUH205gH/HXqZgq3yCxcOLufX/1B6bGcAJUg== X-Received: by 2002:a05:6214:5987:b0:6bd:88d5:fa87 with SMTP id 6a1803df08f44-6c155e1f87dmr36394806d6.55.1724260105489; Wed, 21 Aug 2024 10:08:25 -0700 (PDT) Received: from fauth1-smtp.messagingengine.com (fauth1-smtp.messagingengine.com. [103.168.172.200]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6bf6fdd8875sm63470266d6.16.2024.08.21.10.08.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 21 Aug 2024 10:08:24 -0700 (PDT) Received: from phl-compute-01.internal (phl-compute-01.nyi.internal [10.202.2.41]) by mailfauth.nyi.internal (Postfix) with ESMTP id 662A01200043; Wed, 21 Aug 2024 13:08:23 -0400 (EDT) Received: from phl-mailfrontend-01 ([10.202.2.162]) by phl-compute-01.internal (MEProxy); Wed, 21 Aug 2024 13:08:23 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeeftddruddukedguddtlecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpggftfghnshhusghstghrihgsvgdp uffrtefokffrpgfnqfghnecuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivg hnthhsucdlqddutddtmdenucfjughrpeffhffvvefukfhfgggtuggjsehttdortddttddv necuhfhrohhmpeeuohhquhhnucfhvghnghcuoegsohhquhhnrdhfvghnghesghhmrghilh drtghomheqnecuggftrfgrthhtvghrnhepjeelveeguddvheehvddvkeegvdehgfejhedu geejtedtheekleehieefvdeulefgnecuffhomhgrihhnpehrshdrshgsnecuvehluhhsth gvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepsghoqhhunhdomhgvshhm thhprghuthhhphgvrhhsohhnrghlihhthidqieelvdeghedtieegqddujeejkeehheehvd dqsghoqhhunhdrfhgvnhhgpeepghhmrghilhdrtghomhesfhhigihmvgdrnhgrmhgvpdhn sggprhgtphhtthhopeehfedpmhhouggvpehsmhhtphhouhhtpdhrtghpthhtoheprghlih gtvghrhihhlhesghhoohhglhgvrdgtohhmpdhrtghpthhtoheprhhoshhtvgguthesghho ohgumhhishdrohhrghdprhgtphhtthhopehmhhhirhgrmhgrtheskhgvrhhnvghlrdhorh hgpdhrtghpthhtohepmhgrthhhihgvuhdruggvshhnohihvghrshesvghffhhitghiohhs rdgtohhmpdhrtghpthhtohepphgvthgvrhiisehinhhfrhgruggvrggurdhorhhgpdhrtg hpthhtohepjhhpohhimhgsohgvsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehjsggr rhhonhesrghkrghmrghirdgtohhmpdhrtghpthhtoheprghruggssehkvghrnhgvlhdroh hrghdprhgtphhtthhopehojhgvuggrsehkvghrnhgvlhdrohhrgh X-ME-Proxy: Feedback-ID: iad51458e:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 21 Aug 2024 13:08:22 -0400 (EDT) Date: Wed, 21 Aug 2024 10:08:16 -0700 From: Boqun Feng To: Alice Ryhl Cc: Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Peter Zijlstra , Josh Poimboeuf , Jason Baron , Ard Biesheuvel , Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , 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 Subject: Re: [PATCH v7 5/5] rust: add arch_static_branch Message-ID: References: <20240816-tracepoint-v7-0-d609b916b819@google.com> <20240816-tracepoint-v7-5-d609b916b819@google.com> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240816-tracepoint-v7-5-d609b916b819@google.com> On Fri, Aug 16, 2024 at 11:07:42AM +0000, Alice Ryhl wrote: > To allow the Rust implementation of static_key_false to use runtime code > patching instead of the generic implementation, pull in the relevant > inline assembly from the jump_label.h header by running the C > preprocessor on a .rs.S file. Build rules are added for .rs.S files. > > Since the relevant inline asm has been adjusted to export the inline asm > via the ARCH_STATIC_BRANCH_ASM macro in a consistent way, the Rust side > does not need architecture specific code to pull in the asm. > > It is not possible to use the existing C implementation of > arch_static_branch via a Rust helper because it passes the argument > `key` to inline assembly as an 'i' parameter. Any attempt to add a C > helper for this function will fail to compile because the value of `key` > must be known at compile-time. > > Suggested-by: Peter Zijlstra (Intel) > Co-developed-by: Miguel Ojeda > Signed-off-by: Miguel Ojeda > Signed-off-by: Alice Ryhl > --- > rust/Makefile | 5 ++- > rust/kernel/.gitignore | 3 ++ > rust/kernel/arch_static_branch_asm.rs.S | 7 ++++ > rust/kernel/jump_label.rs | 64 ++++++++++++++++++++++++++++++++- > rust/kernel/lib.rs | 30 ++++++++++++++++ > scripts/Makefile.build | 9 ++++- > 6 files changed, 115 insertions(+), 3 deletions(-) > > diff --git a/rust/Makefile b/rust/Makefile > index 199e0db67962..277fcef656b8 100644 > --- a/rust/Makefile > +++ b/rust/Makefile > @@ -14,6 +14,8 @@ CFLAGS_REMOVE_helpers.o = -Wmissing-prototypes -Wmissing-declarations > always-$(CONFIG_RUST) += libmacros.so > no-clean-files += libmacros.so > > +always-$(subst y,$(CONFIG_RUST),$(CONFIG_JUMP_LABEL)) += kernel/arch_static_branch_asm.rs > + > always-$(CONFIG_RUST) += bindings/bindings_generated.rs bindings/bindings_helpers_generated.rs > obj-$(CONFIG_RUST) += alloc.o bindings.o kernel.o > always-$(CONFIG_RUST) += exports_alloc_generated.h exports_bindings_generated.h \ > @@ -409,7 +411,8 @@ $(obj)/uapi.o: $(src)/uapi/lib.rs \ > $(obj)/kernel.o: private rustc_target_flags = --extern alloc \ > --extern build_error --extern macros --extern bindings --extern uapi > $(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/alloc.o $(obj)/build_error.o \ > - $(obj)/libmacros.so $(obj)/bindings.o $(obj)/uapi.o FORCE > + $(obj)/libmacros.so $(obj)/bindings.o $(obj)/uapi.o \ > + $(obj)/kernel/arch_static_branch_asm.rs FORCE > +$(call if_changed_rule,rustc_library) > > endif # CONFIG_RUST > diff --git a/rust/kernel/.gitignore b/rust/kernel/.gitignore > new file mode 100644 > index 000000000000..d082731007c6 > --- /dev/null > +++ b/rust/kernel/.gitignore > @@ -0,0 +1,3 @@ > +# SPDX-License-Identifier: GPL-2.0 > + > +/arch_static_branch_asm.rs > diff --git a/rust/kernel/arch_static_branch_asm.rs.S b/rust/kernel/arch_static_branch_asm.rs.S > new file mode 100644 > index 000000000000..9e373d4f7567 > --- /dev/null > +++ b/rust/kernel/arch_static_branch_asm.rs.S > @@ -0,0 +1,7 @@ > +// SPDX-License-Identifier: GPL-2.0 > + > +#include > + > +// Cut here. > + > +::kernel::concat_literals!(ARCH_STATIC_BRANCH_ASM("{symb} + {off} + {branch}", "{l_yes}")) > diff --git a/rust/kernel/jump_label.rs b/rust/kernel/jump_label.rs > index 011e1fc1d19a..7757e4f8e85e 100644 > --- a/rust/kernel/jump_label.rs > +++ b/rust/kernel/jump_label.rs > @@ -23,7 +23,69 @@ macro_rules! static_key_false { > let _key: *const $keytyp = ::core::ptr::addr_of!($key); > let _key: *const $crate::bindings::static_key = ::core::ptr::addr_of!((*_key).$field); > > - $crate::bindings::static_key_count(_key.cast_mut()) > 0 > + #[cfg(not(CONFIG_JUMP_LABEL))] > + { > + $crate::bindings::static_key_count(_key.cast_mut()) > 0 > + } > + > + #[cfg(CONFIG_JUMP_LABEL)] > + $crate::jump_label::arch_static_branch! { $key, $keytyp, $field, false } > }}; > } > pub use static_key_false; > + > +/// Assert that the assembly block evaluates to a string literal. > +#[cfg(CONFIG_JUMP_LABEL)] > +const _: &str = include!("arch_static_branch_asm.rs"); Have you try this with "make O="? I hit the following issue, but I am rebasing on rust-dev, so I might miss something: error: couldn't read ../rust/kernel/arch_static_branch_asm.rs: No such file or directory (os error 2) --> ../rust/kernel/jump_label.rs:39:17 | 39 | const _: &str = include!("arch_static_branch_asm.rs"); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: this error originates in the macro `include` (in Nightly builds, run with -Z macro-backtrace for more info) error: aborting due to 1 previous error Regards, Boqun > + > +#[macro_export] > +#[doc(hidden)] > +#[cfg(CONFIG_JUMP_LABEL)] > +#[cfg(not(CONFIG_HAVE_JUMP_LABEL_HACK))] > +macro_rules! arch_static_branch { > + ($key:path, $keytyp:ty, $field:ident, $branch:expr) => {'my_label: { > + $crate::asm!( > + include!(concat!(env!("SRCTREE"), "/rust/kernel/arch_static_branch_asm.rs")); > + l_yes = label { > + break 'my_label true; > + }, > + symb = sym $key, > + off = const ::core::mem::offset_of!($keytyp, $field), > + branch = const $crate::jump_label::bool_to_int($branch), > + ); > + > + break 'my_label false; > + }}; > +} > + > +#[macro_export] > +#[doc(hidden)] > +#[cfg(CONFIG_JUMP_LABEL)] > +#[cfg(CONFIG_HAVE_JUMP_LABEL_HACK)] > +macro_rules! arch_static_branch { > + ($key:path, $keytyp:ty, $field:ident, $branch:expr) => {'my_label: { > + $crate::asm!( > + include!(concat!(env!("SRCTREE"), "/rust/kernel/arch_static_branch_asm.rs")); > + l_yes = label { > + break 'my_label true; > + }, > + symb = sym $key, > + off = const ::core::mem::offset_of!($keytyp, $field), > + branch = const 2 | $crate::jump_label::bool_to_int($branch), > + ); > + > + break 'my_label false; > + }}; > +} > + > +#[cfg(CONFIG_JUMP_LABEL)] > +pub use arch_static_branch; > + > +/// A helper used by inline assembly to pass a boolean to as a `const` parameter. > +/// > +/// Using this function instead of a cast lets you assert that the input is a boolean, and not some > +/// other type that can also be cast to an integer. > +#[doc(hidden)] > +pub const fn bool_to_int(b: bool) -> i32 { > + b as i32 > +} > diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs > index d00a44b000b6..9e9b95ab6966 100644 > --- a/rust/kernel/lib.rs > +++ b/rust/kernel/lib.rs > @@ -145,3 +145,33 @@ macro_rules! container_of { > ptr.sub(offset) as *const $type > }} > } > + > +/// Helper for `.rs.S` files. > +#[doc(hidden)] > +#[macro_export] > +macro_rules! concat_literals { > + ($( $asm:literal )* ) => { > + ::core::concat!($($asm),*) > + }; > +} > + > +/// Wrapper around `asm!` that uses at&t syntax on x86. > +// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` > +// syntax. > +#[cfg(target_arch = "x86_64")] > +#[macro_export] > +macro_rules! asm { > + ($($asm:expr),* ; $($rest:tt)*) => { > + ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* ) > + }; > +} > + > +/// Wrapper around `asm!` that uses at&t syntax on x86. > +// For non-x86 arches we just pass through to `asm!`. > +#[cfg(not(target_arch = "x86_64"))] > +#[macro_export] > +macro_rules! asm { > + ($($asm:expr),* ; $($rest:tt)*) => { > + ::core::arch::asm!( $($asm)*, $($rest)* ) > + }; > +} > diff --git a/scripts/Makefile.build b/scripts/Makefile.build > index 72b1232b1f7d..59fe83fba647 100644 > --- a/scripts/Makefile.build > +++ b/scripts/Makefile.build > @@ -263,12 +263,13 @@ $(obj)/%.lst: $(obj)/%.c FORCE > # Compile Rust sources (.rs) > # --------------------------------------------------------------------------- > > -rust_allowed_features := new_uninit > +rust_allowed_features := asm_const,asm_goto,new_uninit > > # `--out-dir` is required to avoid temporaries being created by `rustc` in the > # current working directory, which may be not accessible in the out-of-tree > # modules case. > rust_common_cmd = \ > + SRCTREE=$(abspath $(srctree)) \ > RUST_MODFILE=$(modfile) $(RUSTC_OR_CLIPPY) $(rust_flags) \ > -Zallow-features=$(rust_allowed_features) \ > -Zcrate-attr=no_std \ > @@ -318,6 +319,12 @@ quiet_cmd_rustc_ll_rs = $(RUSTC_OR_CLIPPY_QUIET) $(quiet_modtag) $@ > $(obj)/%.ll: $(obj)/%.rs FORCE > +$(call if_changed_dep,rustc_ll_rs) > > +quiet_cmd_rustc_rs_rs_S = RSCPP $(quiet_modtag) $@ > + cmd_rustc_rs_rs_S = $(CPP) $(c_flags) -xc -C -P $< | sed '1,/^\/\/ Cut here.$$/d' >$@ > + > +$(obj)/%.rs: $(obj)/%.rs.S FORCE > + +$(call if_changed_dep,rustc_rs_rs_S) > + > # Compile assembler sources (.S) > # --------------------------------------------------------------------------- > > > -- > 2.46.0.184.g6999bdac58-goog >