From nobody Thu Dec 18 15:24:27 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A99DCDB482 for ; Wed, 18 Oct 2023 13:45:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344728AbjJRNpH (ORCPT ); Wed, 18 Oct 2023 09:45:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231562AbjJRNpD (ORCPT ); Wed, 18 Oct 2023 09:45:03 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9571595; Wed, 18 Oct 2023 06:45:01 -0700 (PDT) Date: Wed, 18 Oct 2023 13:44:59 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1697636700; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Mn1R1D8LCZyXRyc+VdxbsLSJ9bsUZqepc3iAJQINwx0=; b=mCxibk6xYxt62iYT5CvrcV5a7mbDgwEAK5eJIFczKY/JTy8hgdWGDNVYFBR6KWDcNqbzZS nMacdn6vrBh4aCZdo1bNgSNcsdcCdaHrE+AZk0jJFoIafgzJxq/ppa7NsWUhlH/ejXP3vM 3ijHemP0528A4eyaHk+fuK6wFZsmtaXT7RcgdEvua5b5rB3oN+LLiw9LQGj02BDfaxHwsA y/xKnr8DjRyU/Qn5GEysfaEKKAK5avbhPxo1++CgyaYWJ/MiPsZ/u8em6+BPQ+JbvxAUhH EfBbACl85PrrDZ0RCYv8SkTpunU3YrWSyjcZ24Uo82v/12A6yXD7tqV6Tk7hxw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1697636700; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Mn1R1D8LCZyXRyc+VdxbsLSJ9bsUZqepc3iAJQINwx0=; b=aZH7NdcWIn71zvYYPCvDu1x/dNBna/ir9tGipZUunernAdQu26L03P8423FxD/2T1Tn+Nw ZetpclpinhBsTjCQ== From: "tip-bot2 for Uros Bizjak" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: x86/percpu] x86/percpu: Use the correct asm operand modifier in percpu_stable_op() Cc: Uros Bizjak , Ingo Molnar , Andy Lutomirski , Brian Gerst , Denys Vlasenko , "H. Peter Anvin" , Linus Torvalds , Josh Poimboeuf , Sean Christopherson , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20231016200755.287403-1-ubizjak@gmail.com> References: <20231016200755.287403-1-ubizjak@gmail.com> MIME-Version: 1.0 Message-ID: <169763669910.3135.5711813859163110694.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the x86/percpu branch of tip: Commit-ID: e39828d2c1c0781ccfcf742791daf88fdfa481ea Gitweb: https://git.kernel.org/tip/e39828d2c1c0781ccfcf742791daf88fd= fa481ea Author: Uros Bizjak AuthorDate: Mon, 16 Oct 2023 22:07:30 +02:00 Committer: Ingo Molnar CommitterDate: Wed, 18 Oct 2023 14:09:16 +02:00 x86/percpu: Use the correct asm operand modifier in percpu_stable_op() The "P" asm operand modifier is a x86 target-specific modifier. When used for a constant, it drops all syntax-specific prefixes and issues the bare constant. This modifier is not correct for address handling, in this case a generic "a" operand modifier should be used. The "a" asm operand modifier substitutes a memory reference, with the actual operand treated as address. For x86_64, when a symbol is provided, the "a" modifier emits "sym(%rip)" instead of "sym", enabling shorter %rip-relative addressing. Clang allows only "i" and "r" operand constraints with an "a" modifier, so the patch normalizes the modifier/constraint pair to "a"/"i" which is consistent between both compilers. The patch reduces code size of a test build by 4072 bytes: text data bss dec hex filename 25523268 4388300 808452 30720020 1d4c014 vmlinux-old.o 25519196 4388300 808452 30715948 1d4b02c vmlinux-new.o [ mingo: Changelog clarity. ] Signed-off-by: Uros Bizjak Signed-off-by: Ingo Molnar Cc: Andy Lutomirski Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Josh Poimboeuf Cc: Uros Bizjak Cc: Sean Christopherson Link: https://lore.kernel.org/r/20231016200755.287403-1-ubizjak@gmail.com --- arch/x86/include/asm/percpu.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h index 5474690..ac3220a 100644 --- a/arch/x86/include/asm/percpu.h +++ b/arch/x86/include/asm/percpu.h @@ -194,9 +194,9 @@ do { \ #define percpu_stable_op(size, op, _var) \ ({ \ __pcpu_type_##size pfo_val__; \ - asm(__pcpu_op2_##size(op, __force_percpu_arg(P[var]), "%[val]") \ + asm(__pcpu_op2_##size(op, __force_percpu_arg(a[var]), "%[val]") \ : [val] __pcpu_reg_##size("=3D", pfo_val__) \ - : [var] "p" (&(_var))); \ + : [var] "i" (&(_var))); \ (typeof(_var))(unsigned long) pfo_val__; \ })