From patchwork Fri Feb 11 10:15:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 12743132 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 B7B23C433F5 for ; Fri, 11 Feb 2022 10:16:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 340196B0078; Fri, 11 Feb 2022 05:16:00 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2F0176B007B; Fri, 11 Feb 2022 05:16:00 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1B6A36B007D; Fri, 11 Feb 2022 05:16:00 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.26]) by kanga.kvack.org (Postfix) with ESMTP id 0CBB86B0078 for ; 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Fri, 11 Feb 2022 11:15:54 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id PxD6oSWwTPjq; Fri, 11 Feb 2022 11:15:54 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (unknown [192.168.6.91]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 0D3FF8B764; Fri, 11 Feb 2022 11:15:54 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 21BAFhgh943140 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Fri, 11 Feb 2022 11:15:43 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 21BAFgp0943138; Fri, 11 Feb 2022 11:15:42 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Andrew Morton Cc: Christophe Leroy , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH v2] mm: Uninline copy_overflow() Date: Fri, 11 Feb 2022 11:15:32 +0100 Message-Id: <1b19e3168b6bed6b9488d35e50a592f5229a2d45.1644574519.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1644574530; l=2540; s=20211009; h=from:subject:message-id; bh=z3J1iKFpDr2MWVTPAEqkcnrhVq1f99BUm63wD5NNhUo=; b=dpgnxmCt8BSkYxfjGRVX30PmvMPKiXnY8MAX17TY+F67vqv67AA+TCpPvoBEGvpZAGMOVDnBPNsu O03T9PlYCqmr2dyCACeKKabPiu0+ux13qW5eVGib6/xj2eJj2j6X X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= Authentication-Results: imf14.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf14.hostedemail.com: domain of christophe.leroy@csgroup.eu designates 93.17.235.10 as permitted sender) smtp.mailfrom=christophe.leroy@csgroup.eu X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: E9C2F100005 X-Stat-Signature: knrktmqbwaz4kcrqt8bh9piu9grgg6xg X-HE-Tag: 1644574558-675163 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: While building a small config with CONFIG_CC_OPTIMISE_FOR_SIZE, I ended up with more than 50 times the following function in vmlinux because GCC doesn't honor the 'inline' keyword: c00243bc : c00243bc: 94 21 ff f0 stwu r1,-16(r1) c00243c0: 7c 85 23 78 mr r5,r4 c00243c4: 7c 64 1b 78 mr r4,r3 c00243c8: 3c 60 c0 62 lis r3,-16286 c00243cc: 7c 08 02 a6 mflr r0 c00243d0: 38 63 5e e5 addi r3,r3,24293 c00243d4: 90 01 00 14 stw r0,20(r1) c00243d8: 4b ff 82 45 bl c001c61c <__warn_printk> c00243dc: 0f e0 00 00 twui r0,0 c00243e0: 80 01 00 14 lwz r0,20(r1) c00243e4: 38 21 00 10 addi r1,r1,16 c00243e8: 7c 08 03 a6 mtlr r0 c00243ec: 4e 80 00 20 blr With -Winline, GCC tells: /include/linux/thread_info.h:212:20: warning: inlining failed in call to 'copy_overflow': call is unlikely and code size would grow [-Winline] copy_overflow() is a non conditional warning called by check_copy_size() on an error path. check_copy_size() have to remain inlined in order to benefit from constant folding, but copy_overflow() is not worth inlining. Uninline it. This reduces the size of vmlinux by almost 4kbytes. Signed-off-by: Christophe Leroy --- v2: Added missing EXPORT_SYMBOL() and enhanced commit message --- include/linux/thread_info.h | 5 +---- mm/maccess.c | 6 ++++++ 2 files changed, 7 insertions(+), 4 deletions(-) diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 73a6f34b3847..1087d1e2be5c 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -209,10 +209,7 @@ __bad_copy_from(void); extern void __compiletime_error("copy destination size is too small") __bad_copy_to(void); -static inline void copy_overflow(int size, unsigned long count) -{ - WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count); -} +void copy_overflow(int size, unsigned long count); static __always_inline __must_check bool check_copy_size(const void *addr, size_t bytes, bool is_source) diff --git a/mm/maccess.c b/mm/maccess.c index d3f1a1f0b1c1..6b11a22f4b01 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -335,3 +335,9 @@ long strnlen_user_nofault(const void __user *unsafe_addr, long count) return ret; } + +void copy_overflow(int size, unsigned long count) +{ + WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count); +} +EXPORT_SYMBOL_GPL(copy_overflow)