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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CDC35C65BA7 for ; Fri, 5 Oct 2018 16:26:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9BBDE208E7 for ; Fri, 5 Oct 2018 16:26:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9BBDE208E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729698AbeJEX0L (ORCPT ); Fri, 5 Oct 2018 19:26:11 -0400 Received: from terminus.zytor.com ([198.137.202.136]:48375 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727878AbeJEX0K (ORCPT ); Fri, 5 Oct 2018 19:26:10 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w95GOrO63209018 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 5 Oct 2018 09:24:53 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w95GOrkT3209015; Fri, 5 Oct 2018 09:24:53 -0700 Date: Fri, 5 Oct 2018 09:24:53 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Arnd Bergmann Message-ID: Cc: luto@kernel.org, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, bp@alien8.de, tglx@linutronix.de, dave.hansen@linux.intel.com, keescook@chromium.org, jroedel@suse.de, peterz@infradead.org, mingo@kernel.org, arnd@arndb.de, toshi.kani@hpe.com, hpa@zytor.com Reply-To: bp@alien8.de, tglx@linutronix.de, akpm@linux-foundation.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, luto@kernel.org, toshi.kani@hpe.com, hpa@zytor.com, arnd@arndb.de, mingo@kernel.org, jroedel@suse.de, peterz@infradead.org, dave.hansen@linux.intel.com, keescook@chromium.org In-Reply-To: <20181005161333.765973-1-arnd@arndb.de> References: <20181005161333.765973-1-arnd@arndb.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/mm: Avoid VLA in pgd_alloc() Git-Commit-ID: 1be3f247c2882a82279cbcf43717581ea943b692 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 1be3f247c2882a82279cbcf43717581ea943b692 Gitweb: https://git.kernel.org/tip/1be3f247c2882a82279cbcf43717581ea943b692 Author: Arnd Bergmann AuthorDate: Fri, 5 Oct 2018 18:13:16 +0200 Committer: Ingo Molnar CommitDate: Fri, 5 Oct 2018 18:16:55 +0200 x86/mm: Avoid VLA in pgd_alloc() Turning on -Wvla found a new VLA usage: arch/x86/mm/pgtable.c: In function 'pgd_alloc': include/linux/build_bug.h:29:45: error: ISO C90 forbids variable length array 'u_pmds' [-Werror=vla] arch/x86/mm/pgtable.c:190:34: note: in expansion of macro 'static_cpu_has' #define PREALLOCATED_USER_PMDS (static_cpu_has(X86_FEATURE_PTI) ? \ ^~~~~~~~~~~~~~ arch/x86/mm/pgtable.c:431:16: note: in expansion of macro 'PREALLOCATED_USER_PMDS' pmd_t *u_pmds[PREALLOCATED_USER_PMDS]; ^~~~~~~~~~~~~~~~~~~~~~ Use the actual size of the array that is used for X86_FEATURE_PTI instead of the variable size. Signed-off-by: Arnd Bergmann Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Joerg Roedel Cc: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Toshi Kani Fixes: 68664695ae57 ("Makefile: Globally enable VLA warning") Fixes: f59dbe9ca670 ("x86/pgtable/pae: Use separate kernel PMDs for user page-table") Link: http://lkml.kernel.org/r/20181005161333.765973-1-arnd@arndb.de Signed-off-by: Ingo Molnar --- arch/x86/mm/pgtable.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 089e78c4effd..386b43e3e0ac 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -189,6 +189,7 @@ static void pgd_dtor(pgd_t *pgd) */ #define PREALLOCATED_USER_PMDS (static_cpu_has(X86_FEATURE_PTI) ? \ KERNEL_PGD_PTRS : 0) +#define MAX_PREALLOCATED_USER_PMDS KERNEL_PGD_PTRS void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd) { @@ -211,6 +212,7 @@ void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd) /* No need to prepopulate any pagetable entries in non-PAE modes. */ #define PREALLOCATED_PMDS 0 #define PREALLOCATED_USER_PMDS 0 +#define MAX_PREALLOCATED_USER_PMDS 0 #endif /* CONFIG_X86_PAE */ static void free_pmds(struct mm_struct *mm, pmd_t *pmds[], int count) @@ -428,8 +430,8 @@ static inline void _pgd_free(pgd_t *pgd) pgd_t *pgd_alloc(struct mm_struct *mm) { pgd_t *pgd; - pmd_t *u_pmds[PREALLOCATED_USER_PMDS]; - pmd_t *pmds[PREALLOCATED_PMDS]; + pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS]; + pmd_t *pmds[MAX_PREALLOCATED_USER_PMDS]; pgd = _pgd_alloc();