tleleu / rpms / kernel

Forked from rpms/kernel 3 years ago
Clone
Pablo Greco d6c4c4
From patchwork Mon Sep 30 05:59:25 2019
Pablo Greco d6c4c4
Content-Type: text/plain; charset="utf-8"
Pablo Greco d6c4c4
MIME-Version: 1.0
Pablo Greco d6c4c4
Content-Transfer-Encoding: 7bit
Pablo Greco d6c4c4
X-Patchwork-Submitter: Masahiro Yamada <yamada.masahiro@socionext.com>
Pablo Greco d6c4c4
X-Patchwork-Id: 1132459
Pablo Greco d6c4c4
Return-Path: <SRS0=rUXN=XZ=vger.kernel.org=linux-kernel-owner@kernel.org>
Pablo Greco d6c4c4
Received: from mail.kernel.org (mail.kernel.org [198.145.29.99])
Pablo Greco d6c4c4
	by smtp.lore.kernel.org (Postfix) with ESMTP id DF215C4360C
Pablo Greco d6c4c4
	for <linux-kernel@archiver.kernel.org>; Mon, 30 Sep 2019 06:02:56 +0000 (UTC)
Pablo Greco d6c4c4
Received: from vger.kernel.org (vger.kernel.org [209.132.180.67])
Pablo Greco d6c4c4
	by mail.kernel.org (Postfix) with ESMTP id B032A20815
Pablo Greco d6c4c4
	for <linux-kernel@archiver.kernel.org>; Mon, 30 Sep 2019 06:02:56 +0000 (UTC)
Pablo Greco d6c4c4
Authentication-Results: mail.kernel.org;
Pablo Greco d6c4c4
	dkim=pass (2048-bit key) header.d=nifty.com header.i=@nifty.com
Pablo Greco d6c4c4
 header.b="sVJyT1RO"
Pablo Greco d6c4c4
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
Pablo Greco d6c4c4
        id S1729635AbfI3GCz (ORCPT
Pablo Greco d6c4c4
        <rfc822;linux-kernel@archiver.kernel.org>);
Pablo Greco d6c4c4
        Mon, 30 Sep 2019 02:02:55 -0400
Pablo Greco d6c4c4
Received: from conuserg-10.nifty.com ([210.131.2.77]:65305 "EHLO
Pablo Greco d6c4c4
        conuserg-10.nifty.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
Pablo Greco d6c4c4
        with ESMTP id S1726121AbfI3GCz (ORCPT
Pablo Greco d6c4c4
        <rfc822;linux-kernel@vger.kernel.org>);
Pablo Greco d6c4c4
        Mon, 30 Sep 2019 02:02:55 -0400
Pablo Greco d6c4c4
Received: from localhost.localdomain (p14092-ipngnfx01kyoto.kyoto.ocn.ne.jp
Pablo Greco d6c4c4
 [153.142.97.92]) (authenticated)
Pablo Greco d6c4c4
        by conuserg-10.nifty.com with ESMTP id x8U60ANM011158;
Pablo Greco d6c4c4
        Mon, 30 Sep 2019 15:00:10 +0900
Pablo Greco d6c4c4
DKIM-Filter: OpenDKIM Filter v2.10.3 conuserg-10.nifty.com x8U60ANM011158
Pablo Greco d6c4c4
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nifty.com;
Pablo Greco d6c4c4
        s=dec2015msa; t=1569823213;
Pablo Greco d6c4c4
        bh=31RHoPop8t0h2pCPRnwABR+VMelvfuLJ6qwFWQxvRAk=;
Pablo Greco d6c4c4
        h=From:To:Cc:Subject:Date:From;
Pablo Greco d6c4c4
        b=sVJyT1ROU+6mzkZMRTb0M214/0QcKkmxRbNgDwh2q1TPJpEjPLOoE+y1jkVndgyce
Pablo Greco d6c4c4
         qBfr7v3nYiN5WSsx5xTwPYvHohsWcSS3AWwyVRw8Kxjd0CGrX8l5WcF76SmCvJPLCB
Pablo Greco d6c4c4
         wLRZ7C1/Z/zv9v8AVlB2BGhDmSvNQJ9bvuGi42d+JbBXGDfg0HZGGHEj7yDDLBV9nW
Pablo Greco d6c4c4
         EZkTGzP6wtIdqgD6DM5Lj4LA7FnlzH8Ocy6yp5agIZ7tdaiVh4E+Xb97KFsLgRin/o
Pablo Greco d6c4c4
         kTPCap5ub1TziurVW+1pbzwH+G3TNVeY+yJdYcAQRFzXXOrTa7s5zIJUtObrYVGCA2
Pablo Greco d6c4c4
         ctH5uaN1kjx1g==
Pablo Greco d6c4c4
X-Nifty-SrcIP: [153.142.97.92]
Pablo Greco d6c4c4
From: Masahiro Yamada <yamada.masahiro@socionext.com>
Pablo Greco d6c4c4
To: linux-arm-kernel@lists.infradead.org,
Pablo Greco d6c4c4
        Russell King <rmk+kernel@armlinux.org.uk>
Pablo Greco d6c4c4
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Pablo Greco d6c4c4
        Olof Johansson <olof@lixom.net>, Arnd Bergmann <arnd@arndb.de>,
Pablo Greco d6c4c4
        Nick Desaulniers <ndesaulniers@google.com>,
Pablo Greco d6c4c4
        Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
Pablo Greco d6c4c4
        Masahiro Yamada <yamada.masahiro@socionext.com>,
Pablo Greco d6c4c4
        Julien Thierry <julien.thierry.kdev@gmail.com>,
Pablo Greco d6c4c4
        Russell King <linux@armlinux.org.uk>,
Pablo Greco d6c4c4
        Stefan Agner <stefan@agner.ch>,
Pablo Greco d6c4c4
        Thomas Gleixner <tglx@linutronix.de>,
Pablo Greco d6c4c4
        Vincent Whitchurch <vincent.whitchurch@axis.com>,
Pablo Greco d6c4c4
        linux-kernel@vger.kernel.org
Pablo Greco d6c4c4
Subject: [PATCH] ARM: fix __get_user_check() in case uaccess_* calls are not
Pablo Greco d6c4c4
 inlined
Pablo Greco d6c4c4
Date: Mon, 30 Sep 2019 14:59:25 +0900
Pablo Greco d6c4c4
Message-Id: <20190930055925.25842-1-yamada.masahiro@socionext.com>
Pablo Greco d6c4c4
X-Mailer: git-send-email 2.17.1
Pablo Greco d6c4c4
Sender: linux-kernel-owner@vger.kernel.org
Pablo Greco d6c4c4
Precedence: bulk
Pablo Greco d6c4c4
List-ID: <linux-kernel.vger.kernel.org>
Pablo Greco d6c4c4
X-Mailing-List: linux-kernel@vger.kernel.org
Pablo Greco d6c4c4
Pablo Greco d6c4c4
KernelCI reports that bcm2835_defconfig is no longer booting since
Pablo Greco d6c4c4
commit ac7c3e4ff401 ("compiler: enable CONFIG_OPTIMIZE_INLINING
Pablo Greco d6c4c4
forcibly"):
Pablo Greco d6c4c4
Pablo Greco d6c4c4
  https://lkml.org/lkml/2019/9/26/825
Pablo Greco d6c4c4
Pablo Greco d6c4c4
I also received a regression report from Nicolas Saenz Julienne:
Pablo Greco d6c4c4
Pablo Greco d6c4c4
  https://lkml.org/lkml/2019/9/27/263
Pablo Greco d6c4c4
Pablo Greco d6c4c4
This problem has cropped up on arch/arm/config/bcm2835_defconfig
Pablo Greco d6c4c4
because it enables CONFIG_CC_OPTIMIZE_FOR_SIZE. The compiler tends
Pablo Greco d6c4c4
to prefer not inlining functions with -Os. I was able to reproduce
Pablo Greco d6c4c4
it with other boards and defconfig files by manually enabling
Pablo Greco d6c4c4
CONFIG_CC_OPTIMIZE_FOR_SIZE.
Pablo Greco d6c4c4
Pablo Greco d6c4c4
The __get_user_check() specifically uses r0, r1, r2 registers.
Pablo Greco d6c4c4
So, uaccess_save_and_enable() and uaccess_restore() must be inlined
Pablo Greco d6c4c4
in order to avoid those registers being overwritten in the callees.
Pablo Greco d6c4c4
Pablo Greco d6c4c4
Prior to commit 9012d011660e ("compiler: allow all arches to enable
Pablo Greco d6c4c4
CONFIG_OPTIMIZE_INLINING"), the 'inline' marker was always enough for
Pablo Greco d6c4c4
inlining functions, except on x86.
Pablo Greco d6c4c4
Pablo Greco d6c4c4
Since that commit, all architectures can enable CONFIG_OPTIMIZE_INLINING.
Pablo Greco d6c4c4
So, __always_inline is now the only guaranteed way of forcible inlining.
Pablo Greco d6c4c4
Pablo Greco d6c4c4
I want to keep as much compiler's freedom as possible about the inlining
Pablo Greco d6c4c4
decision. So, I changed the function call order instead of adding
Pablo Greco d6c4c4
__always_inline around.
Pablo Greco d6c4c4
Pablo Greco d6c4c4
Call uaccess_save_and_enable() before assigning the __p ("r0"), and
Pablo Greco d6c4c4
uaccess_restore() after evacuating the __e ("r0").
Pablo Greco d6c4c4
Pablo Greco d6c4c4
Fixes: 9012d011660e ("compiler: allow all arches to enable CONFIG_OPTIMIZE_INLINING")
Pablo Greco d6c4c4
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Pablo Greco d6c4c4
Reported-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Pablo Greco d6c4c4
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pablo Greco d6c4c4
Acked-by: Arnd Bergmann <arnd@arndb.de>
Pablo Greco d6c4c4
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Pablo Greco d6c4c4
Tested-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Pablo Greco d6c4c4
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Pablo Greco d6c4c4
---
Pablo Greco d6c4c4
Pablo Greco d6c4c4
 arch/arm/include/asm/uaccess.h | 8 +++++---
Pablo Greco d6c4c4
 1 file changed, 5 insertions(+), 3 deletions(-)
Pablo Greco d6c4c4
Pablo Greco d6c4c4
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
Pablo Greco d6c4c4
index 303248e5b990..559f252d7e3c 100644
Pablo Greco d6c4c4
--- a/arch/arm/include/asm/uaccess.h
Pablo Greco d6c4c4
+++ b/arch/arm/include/asm/uaccess.h
Pablo Greco d6c4c4
@@ -191,11 +191,12 @@ extern int __get_user_64t_4(void *);
Pablo Greco d6c4c4
 #define __get_user_check(x, p)						\
Pablo Greco d6c4c4
 	({								\
Pablo Greco d6c4c4
 		unsigned long __limit = current_thread_info()->addr_limit - 1; \
Pablo Greco d6c4c4
+		unsigned int __ua_flags = uaccess_save_and_enable();	\
Pablo Greco d6c4c4
 		register typeof(*(p)) __user *__p asm("r0") = (p);	\
Pablo Greco d6c4c4
 		register __inttype(x) __r2 asm("r2");			\
Pablo Greco d6c4c4
 		register unsigned long __l asm("r1") = __limit;		\
Pablo Greco d6c4c4
 		register int __e asm("r0");				\
Pablo Greco d6c4c4
-		unsigned int __ua_flags = uaccess_save_and_enable();	\
Pablo Greco d6c4c4
+		unsigned int __err;					\
Pablo Greco d6c4c4
 		switch (sizeof(*(__p))) {				\
Pablo Greco d6c4c4
 		case 1:							\
Pablo Greco d6c4c4
 			if (sizeof((x)) >= 8)				\
Pablo Greco d6c4c4
@@ -223,9 +224,10 @@ extern int __get_user_64t_4(void *);
Pablo Greco d6c4c4
 			break;						\
Pablo Greco d6c4c4
 		default: __e = __get_user_bad(); break;			\
Pablo Greco d6c4c4
 		}							\
Pablo Greco d6c4c4
-		uaccess_restore(__ua_flags);				\
Pablo Greco d6c4c4
+		__err = __e;						\
Pablo Greco d6c4c4
 		x = (typeof(*(p))) __r2;				\
Pablo Greco d6c4c4
-		__e;							\
Pablo Greco d6c4c4
+		uaccess_restore(__ua_flags);				\
Pablo Greco d6c4c4
+		__err;							\
Pablo Greco d6c4c4
 	})
Pablo Greco d6c4c4
 
Pablo Greco d6c4c4
 #define get_user(x, p)							\