From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:43012 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757284AbbKFRSM (ORCPT ); Fri, 6 Nov 2015 12:18:12 -0500 Subject: Patch "arm64: compat: fix stxr failure case in SWP emulation" has been added to the 4.2-stable tree To: will.deacon@arm.com, gregkh@linuxfoundation.org, shengjiu.wang@freescale.com, vladimir.murzin@arm.com Cc: , From: Date: Fri, 06 Nov 2015 09:18:08 -0800 Message-ID: <1446830288457@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled arm64: compat: fix stxr failure case in SWP emulation to the 4.2-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm64-compat-fix-stxr-failure-case-in-swp-emulation.patch and it can be found in the queue-4.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 589cb22bbedacf325951014c07a35a2b01ca57f6 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 15 Oct 2015 13:55:53 +0100 Subject: arm64: compat: fix stxr failure case in SWP emulation From: Will Deacon commit 589cb22bbedacf325951014c07a35a2b01ca57f6 upstream. If the STXR instruction fails in the SWP emulation code, we leave *data overwritten with the loaded value, therefore corrupting the data written by a subsequent, successful attempt. This patch re-jigs the code so that we only write back to *data once we know that the update has happened. Fixes: bd35a4adc413 ("arm64: Port SWP/SWPB emulation support from arm") Reported-by: Shengjiu Wang Reported-by: Vladimir Murzin Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/armv8_deprecated.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -279,22 +279,24 @@ static void register_insn_emulation_sysc */ #define __user_swpX_asm(data, addr, res, temp, B) \ __asm__ __volatile__( \ - " mov %w2, %w1\n" \ - "0: ldxr"B" %w1, [%3]\n" \ - "1: stxr"B" %w0, %w2, [%3]\n" \ + "0: ldxr"B" %w2, [%3]\n" \ + "1: stxr"B" %w0, %w1, [%3]\n" \ " cbz %w0, 2f\n" \ " mov %w0, %w4\n" \ + " b 3f\n" \ "2:\n" \ + " mov %w1, %w2\n" \ + "3:\n" \ " .pushsection .fixup,\"ax\"\n" \ " .align 2\n" \ - "3: mov %w0, %w5\n" \ - " b 2b\n" \ + "4: mov %w0, %w5\n" \ + " b 3b\n" \ " .popsection" \ " .pushsection __ex_table,\"a\"\n" \ " .align 3\n" \ - " .quad 0b, 3b\n" \ - " .quad 1b, 3b\n" \ - " .popsection" \ + " .quad 0b, 4b\n" \ + " .quad 1b, 4b\n" \ + " .popsection\n" \ : "=&r" (res), "+r" (data), "=&r" (temp) \ : "r" (addr), "i" (-EAGAIN), "i" (-EFAULT) \ : "memory") Patches currently in stable-queue which might be from will.deacon@arm.com are queue-4.2/arm64-kernel-fix-tcr_el1.t0sz-restore-on-systems-with-extended-idmap.patch queue-4.2/arm64-compat-fix-stxr-failure-case-in-swp-emulation.patch queue-4.2/revert-arm64-unwind-fix-pc-calculation.patch