diff options
Diffstat (limited to 'ARM-fix-__get_user_check-in-case-uaccess_-calls-are-not-inlined.patch')
-rw-r--r-- | ARM-fix-__get_user_check-in-case-uaccess_-calls-are-not-inlined.patch | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/ARM-fix-__get_user_check-in-case-uaccess_-calls-are-not-inlined.patch b/ARM-fix-__get_user_check-in-case-uaccess_-calls-are-not-inlined.patch new file mode 100644 index 000000000..db893d26e --- /dev/null +++ b/ARM-fix-__get_user_check-in-case-uaccess_-calls-are-not-inlined.patch @@ -0,0 +1,143 @@ +From patchwork Mon Sep 30 05:59:25 2019 +Content-Type: text/plain; charset="utf-8" +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +X-Patchwork-Submitter: Masahiro Yamada <yamada.masahiro@socionext.com> +X-Patchwork-Id: 1132459 +Return-Path: <SRS0=rUXN=XZ=vger.kernel.org=linux-kernel-owner@kernel.org> +Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) + by smtp.lore.kernel.org (Postfix) with ESMTP id DF215C4360C + for <linux-kernel@archiver.kernel.org>; Mon, 30 Sep 2019 06:02:56 +0000 (UTC) +Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) + by mail.kernel.org (Postfix) with ESMTP id B032A20815 + for <linux-kernel@archiver.kernel.org>; Mon, 30 Sep 2019 06:02:56 +0000 (UTC) +Authentication-Results: mail.kernel.org; + dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com + header.b="sVJyT1RO" +Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand + id S1729635AbfI3GCz (ORCPT + <rfc822;linux-kernel@archiver.kernel.org>); + Mon, 30 Sep 2019 02:02:55 -0400 +Received: from conuserg-10.nifty.com ([210.131.2.77]:65305 "EHLO + conuserg-10.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org + with ESMTP id S1726121AbfI3GCz (ORCPT + <rfc822;linux-kernel@vger.kernel.org>); + Mon, 30 Sep 2019 02:02:55 -0400 +Received: from localhost.localdomain (p14092-ipngnfx01kyoto.kyoto.ocn.ne.jp + [153.142.97.92]) (authenticated) + by conuserg-10.nifty.com with ESMTP id x8U60ANM011158; + Mon, 30 Sep 2019 15:00:10 +0900 +DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-10.nifty.com x8U60ANM011158 +DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com; + s=dec2015msa; t=1569823213; + bh=31RHoPop8t0h2pCPRnwABR+VMelvfuLJ6qwFWQxvRAk=; + h=From:To:Cc:Subject:Date:From; + b=sVJyT1ROU+6mzkZMRTb0M214/0QcKkmxRbNgDwh2q1TPJpEjPLOoE+y1jkVndgyce + qBfr7v3nYiN5WSsx5xTwPYvHohsWcSS3AWwyVRw8Kxjd0CGrX8l5WcF76SmCvJPLCB + wLRZ7C1/Z/zv9v8AVlB2BGhDmSvNQJ9bvuGi42d+JbBXGDfg0HZGGHEj7yDDLBV9nW + EZkTGzP6wtIdqgD6DM5Lj4LA7FnlzH8Ocy6yp5agIZ7tdaiVh4E+Xb97KFsLgRin/o + kTPCap5ub1TziurVW+1pbzwH+G3TNVeY+yJdYcAQRFzXXOrTa7s5zIJUtObrYVGCA2 + ctH5uaN1kjx1g== +X-Nifty-SrcIP: [153.142.97.92] +From: Masahiro Yamada <yamada.masahiro@socionext.com> +To: linux-arm-kernel@lists.infradead.org, + Russell King <rmk+kernel@armlinux.org.uk> +Cc: Linus Torvalds <torvalds@linux-foundation.org>, + Olof Johansson <olof@lixom.net>, Arnd Bergmann <arnd@arndb.de>, + Nick Desaulniers <ndesaulniers@google.com>, + Nicolas Saenz Julienne <nsaenzjulienne@suse.de>, + Masahiro Yamada <yamada.masahiro@socionext.com>, + Julien Thierry <julien.thierry.kdev@gmail.com>, + Russell King <linux@armlinux.org.uk>, + Stefan Agner <stefan@agner.ch>, + Thomas Gleixner <tglx@linutronix.de>, + Vincent Whitchurch <vincent.whitchurch@axis.com>, + linux-kernel@vger.kernel.org +Subject: [PATCH] ARM: fix __get_user_check() in case uaccess_* calls are not + inlined +Date: Mon, 30 Sep 2019 14:59:25 +0900 +Message-Id: <20190930055925.25842-1-yamada.masahiro@socionext.com> +X-Mailer: git-send-email 2.17.1 +Sender: linux-kernel-owner@vger.kernel.org +Precedence: bulk +List-ID: <linux-kernel.vger.kernel.org> +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 arch/arm/config/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 +in order to avoid those registers being overwritten in the callees. + +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 want to keep as much compiler's freedom as possible about the inlining +decision. So, I changed the function call order instead of adding +__always_inline around. + +Call uaccess_save_and_enable() before assigning the __p ("r0"), and +uaccess_restore() after evacuating the __e ("r0"). + +Fixes: 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING") +Reported-by: "kernelci.org bot" <bot@kernelci.org> +Reported-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> +Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> +Acked-by: Arnd Bergmann <arnd@arndb.de> +Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> +Tested-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com> +Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> +--- + + arch/arm/include/asm/uaccess.h | 8 +++++--- + 1 file changed, 5 insertions(+), 3 deletions(-) + +diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h +index 303248e5b990..559f252d7e3c 100644 +--- a/arch/arm/include/asm/uaccess.h ++++ b/arch/arm/include/asm/uaccess.h +@@ -191,11 +191,12 @@ extern int __get_user_64t_4(void *); + #define __get_user_check(x, p) \ + ({ \ + unsigned long __limit = current_thread_info()->addr_limit - 1; \ ++ unsigned int __ua_flags = uaccess_save_and_enable(); \ + register typeof(*(p)) __user *__p asm("r0") = (p); \ + register __inttype(x) __r2 asm("r2"); \ + register unsigned long __l asm("r1") = __limit; \ + register int __e asm("r0"); \ +- unsigned int __ua_flags = uaccess_save_and_enable(); \ ++ unsigned int __err; \ + switch (sizeof(*(__p))) { \ + case 1: \ + if (sizeof((x)) >= 8) \ +@@ -223,9 +224,10 @@ extern int __get_user_64t_4(void *); + break; \ + default: __e = __get_user_bad(); break; \ + } \ +- uaccess_restore(__ua_flags); \ ++ __err = __e; \ + x = (typeof(*(p))) __r2; \ +- __e; \ ++ uaccess_restore(__ua_flags); \ ++ __err; \ + }) + + #define get_user(x, p) \ |