From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48082 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965367AbbI2OTP (ORCPT ); Tue, 29 Sep 2015 10:19:15 -0400 Subject: Patch "x86/nmi/64: Remove asm code that saves CR2" has been added to the 3.14-stable tree To: luto@kernel.org, bp@suse.de, gregkh@linuxfoundation.org, mingo@kernel.org, peterz@infradead.org, rostedt@goodmis.org, tglx@linutronix.de, torvalds@linux-foundation.org Cc: , From: Date: Tue, 29 Sep 2015 16:19:08 +0200 Message-ID: <1443536348234174@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 x86/nmi/64: Remove asm code that saves CR2 to the 3.14-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: x86-nmi-64-remove-asm-code-that-saves-cr2.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 0e181bb58143cb4a2e8f01c281b0816cd0e4798e Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 15 Jul 2015 10:29:34 -0700 Subject: x86/nmi/64: Remove asm code that saves CR2 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 @@ -1885,28 +1885,10 @@ 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 Patches currently in stable-queue which might be from luto@kernel.org are queue-3.14/x86-nmi-64-use-df-to-avoid-userspace-rsp-confusing-nested-nmi-detection.patch queue-3.14/x86-nmi-enable-nested-do_nmi-handling-for-64-bit-kernels.patch queue-3.14/x86-nmi-64-remove-asm-code-that-saves-cr2.patch queue-3.14/x86-nmi-64-switch-stacks-on-userspace-nmi-entry.patch queue-3.14/x86-nmi-64-improve-nested-nmi-comments.patch queue-3.14/x86-nmi-64-reorder-nested-nmi-checks.patch