From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 745B8483BFB; Fri, 2 Oct 2026 10:57:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790938668; cv=none; b=kGCd7VUIhVuNYynaqLcBbI44MREo9Vx7ffl24oVdjvZcYS3y/LFYIEsUIyf+2TS2R7JFTmhrqA67KiWsyuMZ5YWziUoZCOQuyiSJmPlmtCI6Y/ZKCkuPnYZwfx1jVrIATg/eHBWni2adOuUWE+OLRQzQyNUJ1sLtFL4VjOtPiZA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790938668; c=relaxed/simple; bh=R51dg7ziNjc7/URYyrQ8hbJ1FiRW53tsc+2qT9TtDSk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=FkekjaWfs5hjtUSevl7sPQe4wjnZynR6QUWI1tzVoCsMvvRDp+y6FdOEr2cnIL9QHQYIxmLchHkjcXVvVskfUqO2PfiVDKbVAL90Nw7wTEfYYkXFtMazP0Uu/gV7HOZqfMUVZtmxPfJHCQ9YXpRu6hmXoqeeLXPf1aDuBYOX+LE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aWofcNL0; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aWofcNL0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AFC801F000FF; Fri, 2 Oct 2026 10:57:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790938663; bh=XhYZeDORiSI8/JK5prOnI48AZTeR83aeNlRw2yNVr5w=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=aWofcNL0IpfhNz1F+V5tIezxAIC+6gSsXgAkREeV4BVed+0FiauQXMNWVw9LKPLB6 ir4DE+mQOj7fAnn9wWN24mGIs2yiLoWuxDgSoIcePHXYebp3Jn+1nUa9x2wySQefzf WQmIi/OFo2WoqQKAzGhoPoMrrzBB5bUlFah8eMf2FJVRJ6H6P9gC/qpBZuRnPjv0y/ F5TtGt5oyxTCxCgpw9JS+D+Ugcg53pdmW58E1qfTVRE4UNxCd1Jv8/fulyxe9xvM3n QuSyWTZZF/fLNAxS4cWJJyIBxQRSN/S3tMrqSUHZbQdB27JrxaRUMLy+tg6NqQf98F +C8Ubag62FOcA== From: "Christophe Leroy (CS GROUP)" To: Andy Lutomirski , Thomas Gleixner , Theodore Ts'o , "Jason A. Donenfeld" , Nathan Chancellor Cc: Christophe Leroy , Vincenzo Frascino , Nick Desaulniers , Bill Wendling , Justin Stitt , Catalin Marinas , Will Deacon , Mark Rutland , Huacai Chen , WANG Xuerui , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, llvm@lists.linux.dev Subject: Re: [PATCH v2] random: vDSO: Avoid call to memset() when zeroing reserved in __cvdso_getrandom_data() Date: Fri, 2 Oct 2026 12:57:06 +0200 Message-ID: <179093852073.149722.832232613857480812.b4-ty@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260925-vdso-getrandom-avoid-memset-llvm-24-v2-1-ce640f872393@kernel.org> References: <20260925-vdso-getrandom-avoid-memset-llvm-24-v2-1-ce640f872393@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" X-Developer-Signature: v=1; a=openpgp-sha256; l=948; i=chleroy@kernel.org; h=from:subject:message-id; bh=cZWyz0y5XGYe9zKs9PNHSxiUlxW65egvfT4xEgdntpI=; b=owGbwMvMwCV2d0KB2p7V54MZT6slMWTt7+OJ/rvq89WD/OHOTgfiuFYb3eV9siQjX6ZB4uV8W fGZTfsNOkpZGMS4GGTFFFmO/+feNaPrS2r+1F36MHNYmUCGMHBxCsBElsQyMkw/0pmesd3U1s2/ +cCt35+i1GxcP3PlXZzn80qx+rxOmQLD/5gj9bZ29RUatWfD9vbt1+NKmTHbS7kya1+avMNCTlt NfgA= X-Developer-Key: i=chleroy@kernel.org; a=openpgp; fpr=10FFE6F8B390DE17ACC2632368A92FEB01B8DD78 Content-Transfer-Encoding: 8bit On Fri, 25 Sep 2026 22:46:32 +0100, Nathan Chancellor wrote: > After a recent change in LLVM [1], builds with the random vDSO > implementation, such as PowerPC and RISC-V, fail when checking the vDSO: > > arch/powerpc/kernel/vdso/vdso32.so.dbg: dynamic relocations are not supported > arch/riscv/kernel/vdso/vdso.so.dbg: dynamic relocations are not supported > > memset() is now generated when zeroing params->reserved for some builds > because LLVM has an optimization (now run in more instances) that can > recognize at compile time when it is assigning a static value to a > contiguous area of memory and turn that into a call to memset(). Both > clang and GCC assume memset() is always available [2]. > > [...] Applied, thanks! [1/1] random: vDSO: Avoid call to memset() when zeroing reserved in __cvdso_getrandom_data() (no commit info) Best regards, -- Christophe Leroy (CS GROUP)