Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934927AbbHLJ1U (ORCPT ); Wed, 12 Aug 2015 05:27:20 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:60699 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934338AbbHLI55 (ORCPT ); Wed, 12 Aug 2015 04:57:57 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Andy Lutomirski , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Ben Hutchings , Luis Henriques Subject: [PATCH 3.16.y-ckt 051/118] x86/nmi/64: Remove asm code that saves CR2 Date: Wed, 12 Aug 2015 09:55:53 +0100 Message-Id: <1439369820-27005-52-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1439369820-27005-1-git-send-email-luis.henriques@canonical.com> References: <1439369820-27005-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2187 Lines: 64 3.16.7-ckt16 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski commit 0e181bb58143cb4a2e8f01c281b0816cd0e4798e upstream. Now that do_nmi saves CR2, we don't need to save it in asm. Signed-off-by: Andy Lutomirski Reviewed-by: Steven Rostedt Acked-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar [bwh: Backported to 4.0: adjust filename, context] Signed-off-by: Ben Hutchings [ luis: backported to 3.16: used Ben's backport to 4.0 ] Signed-off-by: Luis Henriques --- arch/x86/kernel/entry_64.S | 18 ------------------ 1 file changed, 18 deletions(-) diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index c0ec84a1890e..5ee10d35d79f 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1636,29 +1636,11 @@ end_repeat_nmi: call save_paranoid DEFAULT_FRAME 0 - /* - * Save off the CR2 register. If we take a page fault in the NMI then - * it could corrupt the CR2 value. If the NMI preempts a page fault - * handler before it was able to read the CR2 register, and then the - * NMI itself takes a page fault, the page fault that was preempted - * will read the information from the NMI page fault and not the - * origin fault. Save it off and restore it if it changes. - * Use the r12 callee-saved register. - */ - movq %cr2, %r12 - /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ movq %rsp,%rdi movq $-1,%rsi call do_nmi - /* Did the NMI take a page fault? Restore cr2 if it did */ - movq %cr2, %rcx - cmpq %rcx, %r12 - je 1f - movq %r12, %cr2 -1: - testl %ebx,%ebx /* swapgs needed? */ jnz nmi_restore nmi_swapgs: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/