From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by smtp.subspace.kernel.org (Postfix) with ESMTP id B52291B5EC8; Thu, 29 Aug 2024 18:10:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=63.228.1.57 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724955010; cv=none; b=IBoxF+215HEz9QRMfrrP+G0FFhgc0y8RON9IXXZ4lt/O1vtro0R2rX3Ed123KpDrwlMqhEQpu66htw+oXSc/d6COUaiPR0HjOsGTlwS5zzqtZn0pv2+VX8bM1T3opx4xDjSaq1dR4HP2prL+KJLFAXEZb2WbTphZHMJerCPCS0Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724955010; c=relaxed/simple; bh=Dk7L9zYDsUOil9EZzG0eOuo3b9mPRIUPgURR2DLTmLM=; h=Date:From:To:Cc:Subject:Message-ID:References:Mime-Version: Content-Type:Content-Disposition:In-Reply-To; b=nMa2BilSPvQ9G8Wg4kHh3MnP0SgXwmyjyRI8KcJ6UdhdLTiEXUNIrBZzClb/Ww3/uwZrV8c3LF/3vF5oMZkdo/PdCaUG3aSDGuV4fk1hXp2Rp0gFrzvL4T/mPkzVFLv0ITRtoc73Tfj5JZltRsLX6VGN08pPgpMRFDbFThiZGJM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org; spf=pass smtp.mailfrom=kernel.crashing.org; arc=none smtp.client-ip=63.228.1.57 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.crashing.org 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> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: 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