Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755097AbbHNSTA (ORCPT ); Fri, 14 Aug 2015 14:19:00 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:51144 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932435AbbHNRnM (ORCPT ); Fri, 14 Aug 2015 13:43:12 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Lutomirski , Steven Rostedt , Borislav Petkov , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.1 33/84] x86/nmi/64: Remove asm code that saves CR2 Date: Fri, 14 Aug 2015 10:42:01 -0700 Message-Id: <20150814174211.223520245@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150814174210.214822912@linuxfoundation.org> References: <20150814174210.214822912@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1917 Lines: 62 4.1-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 Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/entry_64.S | 18 ------------------ 1 file changed, 18 deletions(-) --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1603,29 +1603,11 @@ end_repeat_nmi: call paranoid_entry 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/