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 26E113EB10C; Thu, 1 Oct 2026 10:48:20 +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=1790851702; cv=none; b=I/IoqP40qbUTKFu1sD6Zguce3tf5t16+9pdUZq0u6TkCgYW4StkIBQ+m/utLpqZMXmkK8HaCvZ601kaQfW13kOzPaooQUTDyxo7zaDwULlSsbDcum5CcsviGmc1Fn8HlP91TTrCIZD/r/R7vHoumhcUv4JDE8O9bWlWsOziRFuc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790851702; c=relaxed/simple; bh=Nk60LiUU20mXr1zbUVNQcc4+c0dxMgDULcPnYRde7Y0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=tu/jHhEuBJrwjFEMZ9VGDqX1v7L14TVy0ODrwgOQU7aWJujiIMrPJDefNR1ILuJygHK6x0c68OYf4gqlCHcuL7ETWT8GeFS879VYIhpkHCXiU4sMuA6fKlsFUdPrY/TpMr/YeyML3qy0D83Z9ACdOaQth1VQmhfjlpjrMvZSiFI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=B57mDsY4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="B57mDsY4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D6031F000FF; Thu, 1 Oct 2026 10:48:17 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=zx2c4.com header.i=@zx2c4.com header.a=rsa-sha256 header.s=20210105 header.b=B57mDsY4 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1790851695; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/oOpPY/gsh1NivZHQbt/4ewXmUw4hi2f8c5A+91XjAQ=; b=B57mDsY4+jopKLImXZNVOWxdVpQrgNONXSBu75IrKyl7123Al4mEDaeWWuv661fwT5QFtp DyBe8f04ARHZI529RupFjeyvDFHWlpXWFuVEmNR4jf9UiXLsJ+Xu0/uwQUzKXb1sdqw5Bu rwXQT6Por1A+lDJO9XzMggVf/BrbZ0A= Received: by mail.zx2c4.com (OpenSMTPD) with ESMTPSA id 03abc62d (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 1 Oct 2026 10:48:15 +0000 (UTC) Date: Thu, 1 Oct 2026 12:48:10 +0200 From: "Jason A. Donenfeld" To: Nathan Chancellor Cc: "Christophe Leroy (CS GROUP)" , Nick Desaulniers , Andy Lutomirski , Thomas Gleixner , Theodore Ts'o , Vincenzo Frascino , 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() Message-ID: References: <20260930133813.GA3142230@ax162> <20260930151337.GD3142230@ax162> <20261001102059.GA4176271@ax162> 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 Content-Disposition: inline In-Reply-To: <20261001102059.GA4176271@ax162> On Thu, Oct 01, 2026 at 12:20:59PM +0200, Nathan Chancellor wrote: > control. The change that introduced -max-store-memset only did it to > "allow fine-tuning of the inlining threshold for performance analysis > and optimization". If they decide to remove it for whatever reason, > we're back to square one. I suppose all the more reason to get -finline-stringops=memset added to clang. Then the dual-default thing you came up with below will naturally start choosing the first option when it becomes available. > I know something like below would be uglier due to the ifdef but it > would avoid changing anything for GCC while clearing up the issue at > hand for clang in a guaranteed stable and succinct manner. But then we're back to the byte-by-byte codegen that Christophe pointed out. > If that is not acceptable, something like the following does appear to > work for me. Okay, great, let's do that. Does this commit seem okay with you? I used the diff you sent below and adjusted the commit message: https://git.zx2c4.com/linux-rng/commit/?id=56ff95ee85715047eb5b5220243778af657778c8 Jason