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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 C46C6C388F3 for ; Tue, 1 Oct 2019 08:39:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 92D95215EA for ; Tue, 1 Oct 2019 08:39:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com header.b="p91ffoOa" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733097AbfJAIjj (ORCPT ); Tue, 1 Oct 2019 04:39:39 -0400 Received: from conuserg-07.nifty.com ([210.131.2.74]:21926 "EHLO conuserg-07.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727274AbfJAIji (ORCPT ); Tue, 1 Oct 2019 04:39:38 -0400 Received: from localhost.localdomain (p14092-ipngnfx01kyoto.kyoto.ocn.ne.jp [153.142.97.92]) (authenticated) by conuserg-07.nifty.com with ESMTP id x918bGRK010166; Tue, 1 Oct 2019 17:37:16 +0900 DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-07.nifty.com x918bGRK010166 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; s=dec2015msa; t=1569919038; bh=5vgn6LNEnRoez/oiB48qIZvraN4rGfguB7nlITyUZnQ=; h=From:To:Cc:Subject:Date:From; b=p91ffoOa2E/AqaszRIYAKxH64lj7JJFDmZ79GZ/o3VRI/mwetxYYTQsnMaUw14GmA ZVm6pzze0VUYtB3hV7bLkjiHP+ofi+YmdztVAuitDJ3kA93dhWnhTO8TVLFTz6Dl7g XvOobdLSRmBFYm3F1wliVdaWSZMBm6GoDv/aBdFWMv2Rmxw2+0ZeUdVRufx3OS7r0P Hs72Fd2OSDGs662tuHHS+kUJnTYqsSs2+cjjh4jfgQUE+jKBtvSnylC86v6Zs0O5G6 WF0bdsK1XFHCIBi6PJrD9ZiZqjOv17oQVq7jZI87bIrFBpbYdHV9ykA61Q81Qo8YXo +B0Gs6PCTXyTQ== X-Nifty-SrcIP: [153.142.97.92] From: Masahiro Yamada To: linux-arm-kernel@lists.infradead.org, Russell King Cc: Linus Torvalds , Olof Johansson , Arnd Bergmann , Nick Desaulniers , Nicolas Saenz Julienne , Masahiro Yamada , Allison Randal , Enrico Weigelt , Greg Kroah-Hartman , Julien Thierry , Kate Stewart , Russell King , Stefan Agner , Thomas Gleixner , Vincent Whitchurch , linux-kernel@vger.kernel.org Subject: [PATCH v2] ARM: add __always_inline to functions called from __get_user_check() Date: Tue, 1 Oct 2019 17:37:01 +0900 Message-Id: <20191001083701.27207-1-yamada.masahiro@socionext.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org KernelCI reports that bcm2835_defconfig is no longer booting since commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly") (https://lkml.org/lkml/2019/9/26/825). I also received a regression report from Nicolas Saenz Julienne (https://lkml.org/lkml/2019/9/27/263). This problem has cropped up on bcm2835_defconfig because it enables CONFIG_CC_OPTIMIZE_FOR_SIZE. The compiler tends to prefer not inlining functions with -Os. I was able to reproduce it with other boards and defconfig files by manually enabling CONFIG_CC_OPTIMIZE_FOR_SIZE. The __get_user_check() specifically uses r0, r1, r2 registers. So, uaccess_save_and_enable() and uaccess_restore() must be inlined. Otherwise, those register assignments would be entirely dropped, according to my analysis of the disassembly. Prior to commit 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING"), the 'inline' marker was always enough for inlining functions, except on x86. Since that commit, all architectures can enable CONFIG_OPTIMIZE_INLINING. So, __always_inline is now the only guaranteed way of forcible inlining. I also added __always_inline to 4 functions in the call-graph from the __get_user_check() macro. Fixes: 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING") Reported-by: "kernelci.org bot" Reported-by: Nicolas Saenz Julienne Signed-off-by: Masahiro Yamada --- Changes in v2: - Use __always_inline instead of changing the function call places (per Russell King) - The previous submission is: https://lore.kernel.org/patchwork/patch/1132459/ arch/arm/include/asm/domain.h | 8 ++++---- arch/arm/include/asm/uaccess.h | 4 ++-- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/arch/arm/include/asm/domain.h b/arch/arm/include/asm/domain.h index 567dbede4785..f1d0a7807cd0 100644 --- a/arch/arm/include/asm/domain.h +++ b/arch/arm/include/asm/domain.h @@ -82,7 +82,7 @@ #ifndef __ASSEMBLY__ #ifdef CONFIG_CPU_CP15_MMU -static inline unsigned int get_domain(void) +static __always_inline unsigned int get_domain(void) { unsigned int domain; @@ -94,7 +94,7 @@ static inline unsigned int get_domain(void) return domain; } -static inline void set_domain(unsigned val) +static __always_inline void set_domain(unsigned int val) { asm volatile( "mcr p15, 0, %0, c3, c0 @ set domain" @@ -102,12 +102,12 @@ static inline void set_domain(unsigned val) isb(); } #else -static inline unsigned int get_domain(void) +static __always_inline unsigned int get_domain(void) { return 0; } -static inline void set_domain(unsigned val) +static __always_inline void set_domain(unsigned int val) { } #endif diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 303248e5b990..98c6b91be4a8 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -22,7 +22,7 @@ * perform such accesses (eg, via list poison values) which could then * be exploited for priviledge escalation. */ -static inline unsigned int uaccess_save_and_enable(void) +static __always_inline unsigned int uaccess_save_and_enable(void) { #ifdef CONFIG_CPU_SW_DOMAIN_PAN unsigned int old_domain = get_domain(); @@ -37,7 +37,7 @@ static inline unsigned int uaccess_save_and_enable(void) #endif } -static inline void uaccess_restore(unsigned int flags) +static __always_inline void uaccess_restore(unsigned int flags) { #ifdef CONFIG_CPU_SW_DOMAIN_PAN /* Restore the user access mask */ -- 2.17.1