Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933253AbbHXJRi (ORCPT ); Mon, 24 Aug 2015 05:17:38 -0400 Received: from mx2.suse.de ([195.135.220.15]:58157 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932810AbbHXJKN (ORCPT ); Mon, 24 Aug 2015 05:10:13 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Andy Lutomirski , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Jiri Slaby Subject: [PATCH 3.12 58/82] x86/nmi/64: Remove asm code that saves CR2 Date: Mon, 24 Aug 2015 11:09:18 +0200 Message-Id: <1965b0c76bdcabfa455f141f9ebfe89ee9f862e7.1440407339.git.jslaby@suse.cz> X-Mailer: git-send-email 2.5.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2009 Lines: 64 From: Andy Lutomirski 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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 Signed-off-by: Jiri Slaby --- 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 7b22af265d12..fd27e5b86d7b 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1876,29 +1876,11 @@ 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: -- 2.5.0 -- 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/