From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out4-smtp.messagingengine.com ([66.111.4.28]:57385 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750871AbbKFF4r (ORCPT ); Fri, 6 Nov 2015 00:56:47 -0500 Received: from compute2.internal (compute2.nyi.internal [10.202.2.42]) by mailout.nyi.internal (Postfix) with ESMTP id 004EC2074D for ; Fri, 6 Nov 2015 00:56:46 -0500 (EST) Subject: FAILED: patch "[PATCH] arm64: compat: fix stxr failure case in SWP emulation" failed to apply to 4.2-stable tree To: will.deacon@arm.com, shengjiu.wang@freescale.com, stable@vger.kernel.org, vladimir.murzin@arm.com Cc: From: Date: Thu, 05 Nov 2015 21:56:45 -0800 Message-ID: <144678940518864@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: The patch below does not apply to the 4.2-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From 589cb22bbedacf325951014c07a35a2b01ca57f6 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 15 Oct 2015 13:55:53 +0100 Subject: [PATCH] arm64: compat: fix stxr failure case in SWP emulation 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. Cc: Fixes: bd35a4adc413 ("arm64: Port SWP/SWPB emulation support from arm") Reported-by: Shengjiu Wang Reported-by: Vladimir Murzin Signed-off-by: Will Deacon diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c index bcee7abac68e..937f5e58a4d3 100644 --- a/arch/arm64/kernel/armv8_deprecated.c +++ b/arch/arm64/kernel/armv8_deprecated.c @@ -284,21 +284,23 @@ static void register_insn_emulation_sysctl(struct ctl_table *table) __asm__ __volatile__( \ ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, \ CONFIG_ARM64_PAN) \ - " 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" \ + " .quad 0b, 4b\n" \ + " .quad 1b, 4b\n" \ " .popsection\n" \ ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, \ CONFIG_ARM64_PAN) \