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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E922DC87FCD for ; Thu, 29 Aug 2024 18:06:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 490B76B00B4; Thu, 29 Aug 2024 14:06:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 440BD6B00B6; Thu, 29 Aug 2024 14:06:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 308466B00B7; Thu, 29 Aug 2024 14:06:35 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 0B2456B00B4 for ; Thu, 29 Aug 2024 14:06:35 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 6E88EA11AC for ; Thu, 29 Aug 2024 18:06:34 +0000 (UTC) X-FDA: 82506063108.10.DE3792E Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) by imf14.hostedemail.com (Postfix) with ESMTP id 5AD0A100004 for ; Thu, 29 Aug 2024 18:06:32 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf14.hostedemail.com: domain of segher@kernel.crashing.org designates 63.228.1.57 as permitted sender) smtp.mailfrom=segher@kernel.crashing.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724954693; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=M2EXF4QOW7B4s/ekQXjuln9WzllK4pkYg0nLXXL7tBw=; b=dHYqgGKXoCR9/hfvJ4GbthoomGt/QBK/YLSznuiTZRraNVO6mS21F4lzzL8ULRngPccwsl 6gjsLpZgG/ig6B6ltivMsRzeHR4bZHtVVEfYetSvHkrllXj2Fifc1Q5C8trOSJQSgeVolp r/Q23T/sp83SRcWiZvP6/BOVzcLZUds= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724954693; a=rsa-sha256; cv=none; b=LPitTO+Dq3uhlkE4EBxYZxBo7ysETK7Tfz9WoawBiYLbNYOBCn9Cah8f2RC5eN8IcBLIQJ 9aEUxEVdS6x/N9HF00Zpp0LNDJah7M/4GZG/B/EM8l691hw6XVZBd2nGuXEI1XxFU8aw5m zeR54+ehXyk2J4ITmLyzT0NTqL5CjnM= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf14.hostedemail.com: domain of segher@kernel.crashing.org designates 63.228.1.57 as permitted sender) smtp.mailfrom=segher@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> 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 X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 5AD0A100004 X-Stat-Signature: cjmhekdqub35tzj1iwykjak68xumoptg X-Rspam-User: X-HE-Tag: 1724954792-631918 X-HE-Meta: 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 niOahDeX iuhQ91uMJ3RVRS/rbkY7n3BcnOi4dIUO3E0Gxo35iKBIcew2ij5vl3kyzeaI/Bn/4yXCw7RttBnfcMT6SZN0vQvHivIaqgJJJ6RfneEcXWLyLssOwfdRLyU8VgJ5w0vsT/w5v X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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