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 70EB2C433FE for ; Tue, 15 Nov 2022 20:57:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 12D756B007E; Tue, 15 Nov 2022 15:57:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0DE2C6B0080; Tue, 15 Nov 2022 15:57:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EC0908E0002; Tue, 15 Nov 2022 15:57:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id DAD376B007E for ; Tue, 15 Nov 2022 15:57:06 -0500 (EST) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id B055D1A0507 for ; Tue, 15 Nov 2022 20:57:06 +0000 (UTC) X-FDA: 80136886452.16.5EFE8C5 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf15.hostedemail.com (Postfix) with ESMTP id 03984A0010 for ; Tue, 15 Nov 2022 20:57:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=5xpV9WfbtmqX+4AnIe4/hDPc2QaV12bRadfZHnoqeoI=; b=tml2TgJH1mD2dmkD+cLwZIUZVu fr/XlobwIp+nHqDydSxYztW3WSHwPbxb8w9Fs5rbWAFS9TirYPXwzjJJ2m/IJuaVGFkW6EVESaAtJ h7Not2ly4fXX0XlbCo2v/aaJUQH6yqC3j/KUNrvX58PMWyltZVeMTLMxs2qluXWjzKNdVPXMp0Kpo 1WqIY+BhrdxAuDuZQOmVLCKzVdRLwWs4tpKXXHtiMoK44YGrUnox4fUs8FTGFRk3fFEmltDBxAFvi nCQMVRjQHaWkHieB0wcGJNNWFfcU4Ja68+OTbReRhuUL3QmDe/DPG4JkjFzpd5NVV2jLFI19ET8Hn pW7afWsA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1ov2zF-00Gdjt-J5; Tue, 15 Nov 2022 20:56:54 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A1314300282; Tue, 15 Nov 2022 21:56:45 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8E5BD2CCDC2B8; Tue, 15 Nov 2022 21:56:45 +0100 (CET) Date: Tue, 15 Nov 2022 21:56:45 +0100 From: Peter Zijlstra To: "Edgecombe, Rick P" Cc: "bsingharora@gmail.com" , "hpa@zytor.com" , "Syromiatnikov, Eugene" , "rdunlap@infradead.org" , "keescook@chromium.org" , "Yu, Yu-cheng" , "dave.hansen@linux.intel.com" , "kirill.shutemov@linux.intel.com" , "Eranian, Stephane" , "linux-mm@kvack.org" , "fweimer@redhat.com" , "nadav.amit@gmail.com" , "jannh@google.com" , "dethoma@microsoft.com" , "kcc@google.com" , "linux-arch@vger.kernel.org" , "bp@alien8.de" , "oleg@redhat.com" , "hjl.tools@gmail.com" , "Yang, Weijiang" , "Lutomirski, Andy" , "pavel@ucw.cz" , "arnd@arndb.de" , "tglx@linutronix.de" , "mike.kravetz@oracle.com" , "x86@kernel.org" , "linux-doc@vger.kernel.org" , "jamorris@linux.microsoft.com" , "john.allen@amd.com" , "rppt@kernel.org" , "mingo@redhat.com" , "Shankar, Ravi V" , "corbet@lwn.net" , "linux-kernel@vger.kernel.org" , "linux-api@vger.kernel.org" , "gorcunov@gmail.com" , "akpm@linux-foundation.org" Subject: Re: [PATCH v3 18/37] mm: Add guard pages around a shadow stack. Message-ID: References: <20221104223604.29615-1-rick.p.edgecombe@intel.com> <20221104223604.29615-19-rick.p.edgecombe@intel.com> <6e402f94fe1e942116aca729f1d54fd1399cb98a.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6e402f94fe1e942116aca729f1d54fd1399cb98a.camel@intel.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1668545826; a=rsa-sha256; cv=none; b=LBy0vsP+efVdFTXRr8RNNF3IIo7NANcozcn5fFpiW6v0+TcQiEmHYXytVRDlqTVxYEymec 0IZigXl7aQIDQOKnR21BmuShC5jw9MUJNWyoejHeTYEDLKYPBUcUwYOxy7t/ZeGEPzAWvj dEk4tne9kL+Xo9/pixEVmJdNVkZs//o= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=tml2TgJH; dmarc=none; spf=none (imf15.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=peterz@infradead.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1668545826; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=5xpV9WfbtmqX+4AnIe4/hDPc2QaV12bRadfZHnoqeoI=; b=n1t/3oYI3t8k/vCzQU3Oh7W0MkS0Ei71G17s4VpZrH2Mjj6XHi2zcDsTxHSYPT4ABF+OtL cTBDeM0mIXA2lx2o6cnDHT8CeCIC6MOtuodQ6hE1QRPxn0UG47A0pGonBbDlDiAylxW5dS wS8ghar+r0EfJCgyKY6JXZKIQftFFs8= Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=tml2TgJH; dmarc=none; spf=none (imf15.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=peterz@infradead.org X-Rspam-User: X-Stat-Signature: bh4nyxtf4doo34opgohj7iyhgnbx6a1x X-Rspamd-Queue-Id: 03984A0010 X-Rspamd-Server: rspam11 X-HE-Tag: 1668545825-726020 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: On Tue, Nov 15, 2022 at 08:40:19PM +0000, Edgecombe, Rick P wrote: > > > +unsigned long __weak stack_guard_start_gap(struct vm_area_struct > > > *vma) > > > +{ > > > + if (vma->vm_flags & VM_GROWSDOWN) > > > + return stack_guard_gap; > > > + return 0; > > > +} > > > > I'm thinking perhaps this wants to be an inline function? > > I don't think it can work with weak then. That was kinda the point, __weak sucks and this is very small in any case.