From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2DF2B2E7F3F; Fri, 7 Nov 2025 19:13:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762542831; cv=none; b=oKg3a82xkgrHQAHB+1nz9iw7kXOUxCM774dCGCss8HO/O+/Lb/jaRS3Qp1uQADGRUSNRjoHzCOiF/mjJGh5bxc6ElV2kiJj7snltbZiiIdyNCPEqnIuGUOUJ+NppqjIhj3Ztn5QKeKGNB4Pl/v9FE5aqikE8uGHz9z8x0tdavkQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762542831; c=relaxed/simple; bh=QPvzf1ncoB2akJVkCU9fnOKK8+smlfhFLevU4TnM4/I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=D6I2mvaNDX2TKU3DCyvnu47rZ2C4NP1kI1lrOdHljworh75XxSnWrlaZJugOIWqDKr/NdVyE+G2HEad4b0oAeiQtJhmugJijHa0ry11UzCn783Kp7hhA16OG+EnOq7wZ6YPLxOH/JOSVEYCnkCl9bA0F1nZ4i3YMqCCuxPv+KsI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=hfd6kSqa; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="hfd6kSqa" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFA61C116C6; Fri, 7 Nov 2025 19:13:48 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="hfd6kSqa" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1762542827; 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=g9Te8GHaL0ce//jLPAsz2MwD/P3XSQZAUk5sFkofyv8=; b=hfd6kSqaknI2Wd4hZsGmzGAGKB+4Sqsz1FlvG10wU6tNM5nW5DAnBl//wiECgOZiQIS+9H Y2Rh2yY5KKP8rFYmpxZjsIi0KU4kbqZb+TFqewtpbBPZhDjSKrs0KY1gK1F1uhW9eDTvdY zpdrtAZzzEKmIbBkB78DZlqqFMjuczI= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 3582e0ca (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Fri, 7 Nov 2025 19:13:46 +0000 (UTC) Date: Fri, 7 Nov 2025 20:13:28 +0100 From: "Jason A. Donenfeld" To: Thiago Macieira Cc: Borislav Petkov , Christopher Snowhill , Gregory Price , x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com, peterz@infradead.org, mario.limonciello@amd.com, riel@surriel.com, yazen.ghannam@amd.com, me@mixaill.net, kai.huang@intel.com, sandipan.das@amd.com, darwi@linutronix.de, stable@vger.kernel.org Subject: Re: [PATCH v2] x86/amd: Disable RDSEED on AMD Zen5 because of an error. Message-ID: References: <4632322.0HT0TaD9VG@tjmaciei-mobl5> <1903914.sHLxoZxqIA@tjmaciei-mobl5> 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: <1903914.sHLxoZxqIA@tjmaciei-mobl5> On Wed, Nov 05, 2025 at 08:41:01AM -0800, Thiago Macieira wrote: > > Oh yea, good question. Well, with every major OS now having a mechanism > > to skip syscalls for random numbers, I guess you could indeed just alias > > global() to system() and call it a day. Then users really cannot shoot > > themselves in the foot. That would be simpler too. Seems like the best > > option. > > Indeed. > > But consider people who haven't upgraded Linux (yes, we get people asking to > keep everything intact in their system, but upgrade Qt only, then complain > when our dependency minimums change). How much of an impact would they have? I suppose you could benchmark it and see if it matters. The syscall is obviously slower than the megafast vDSO code, so it will probably also be a bit slower than the MT code. But I suspect for most use cases maybe it doesn't matter that much? It's worth a try and seeing if anybody complains. Jason