From mboxrd@z Thu Jan 1 00:00:00 1970 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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 65890C8303E for ; Thu, 29 Aug 2024 18:09:59 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Wvq7T6QJJz2yxN; Fri, 30 Aug 2024 04:09:57 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=63.228.1.57 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1724954997; cv=none; b=YQUCtRoJaNYPAaB3C9KhUlYB7JyfPKOLEeHFEpljhrlfdCmbkRzIUVbriwOke4xIo4O0feJx1reZo30ogFMXS6jFdzgML0+a6DuVQY9w7vfLQejewnHBYRabCUXTzIGbZChWLONg5o3dNRQQp/t659pnohrrMrNl7jvkHwRgC9S20hK/YTZrj6gtw6SOpHFkjJLEHtv8ts41Kx7Xk5NMju3N2VD7v9t8ZDXZbjjMlbgasxFdHLO4ceYqoSla+Pk43r1v1VCjTTibxBN4tIDkcMyS5R0gtE9Tndc4PBzOGfiAa9/WRLKlPBNZ9zy01Zk9gDse8T35z85iLohevFneSg== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1724954997; c=relaxed/relaxed; bh=M2EXF4QOW7B4s/ekQXjuln9WzllK4pkYg0nLXXL7tBw=; h=Received:Received:X-Authentication-Warning:Date:From:To:Cc: Subject:Message-ID:References:Mime-Version:Content-Type: Content-Disposition:Content-Transfer-Encoding:In-Reply-To: User-Agent; b=d82/KHu/FaroVvpO2sqaqECdDv4WWSOyUgRrbQr3AWVrLmWj1d//uiEy+yhzQ0y+q57LDqwLsiFUocWiS9EdFCS0ZsQChJDiP/pr8uE3TZ2ipsNmpmjjMeBJMQudiwm5kgIoVUw1k9PGPOmeIp6WAzpVH5u9ziDlPn2ce16St2GVnhB8Kc3VtcSX6MhKlrdpGiTkNue6B013jZciZ2VAY/LZQglDeWver9WwdZMmse7TZyOjIN8X3E+S15BeGh+wTMbcpFcwPnMkeoniXHjcrtRbeoskDjAqo2innuUsIUusFjl7FXwUD6Ia8aS2mnI+W72cZmmIjafXOTKXq/EKvw== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org; spf=pass (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=lists.ozlabs.org) smtp.mailfrom=kernel.crashing.org Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=lists.ozlabs.org) Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by lists.ozlabs.org (Postfix) with ESMTP id 4Wvq7S6kMnz2yxL for ; Fri, 30 Aug 2024 04:09:56 +1000 (AEST) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 47TI2hac000933; Thu, 29 Aug 2024 13:02:44 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 47TI2fBi000932; Thu, 29 Aug 2024 13:02:41 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Thu, 29 Aug 2024 13:02:41 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Ard Biesheuvel , Arnd Bergmann , "Jason A . Donenfeld" , Eric Biggers , Michael Ellerman , Nicholas Piggin , Naveen N Rao , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , "Theodore Ts'o" , Andrew Morton , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Vincenzo Frascino , shuah , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Linux-Arch , linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v2 05/17] vdso: Avoid call to memset() by getrandom Message-ID: <20240829180241.GJ29862@gate.crashing.org> References: <20240827180819.GB2049@sol.localdomain> <20240827225330.GC29862@gate.crashing.org> <20240828124519.GE29862@gate.crashing.org> <20240828162025.GG29862@gate.crashing.org> <20240828172538.GI29862@gate.crashing.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Post: List-Subscribe: , , List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.4.2.3i On Thu, Aug 29, 2024 at 07:36:38PM +0200, Christophe Leroy wrote: > > > Le 28/08/2024 à 19:25, Segher Boessenkool a écrit : > > > >>Not sure about static binaries, though: do those even use the VDSO? > > > >With "static binary" people usually mean "a binary not using any DSOs", > >I think the VDSO is a DSO, also in this respect? As always, -static > >builds are *way* less problematic (and faster and smaller :-) ) > > > > AFAIK on powerpc even static binaries use the vDSO, otherwise signals > don't work. How can that work? Non-dynamic binaries do not use ld.so (that is the definition of a dynamic binary, even). So they cannot link (at runtime) to any DSO (unless that is done manually?!) Maybe there is something at a fixed offset in the vDSO, or something like that? Is this documented somewhere? Segher