Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752070AbeACUNH (ORCPT + 1 other); Wed, 3 Jan 2018 15:13:07 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:32898 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751753AbeACUNF (ORCPT ); Wed, 3 Jan 2018 15:13:05 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hugh Dickins , Jiri Kosina Subject: [PATCH 4.4 08/37] kaiser: fix regs to do_nmi() ifndef CONFIG_KAISER Date: Wed, 3 Jan 2018 21:11:14 +0100 Message-Id: <20180103195057.292615142@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180103195056.837404126@linuxfoundation.org> References: <20180103195056.837404126@linuxfoundation.org> User-Agent: quilt/0.65 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 Return-Path: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hugh Dickins pjt has observed that nmi's second (nmi_from_kernel) call to do_nmi() adjusted the %rdi regs arg, rightly when CONFIG_KAISER, but wrongly when not CONFIG_KAISER. Although the minimal change is to add an #ifdef CONFIG_KAISER around the addq line, that looks cluttered, and I prefer how the first call to do_nmi() handled it: prepare args in %rdi and %rsi before getting into the CONFIG_KAISER block, since it does not touch them at all. And while we're here, place the "#ifdef CONFIG_KAISER" that follows each, to enclose the "Unconditionally restore CR3" comment: matching how the "Unconditionally use kernel CR3" comment above is enclosed. Signed-off-by: Hugh Dickins Acked-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- arch/x86/entry/entry_64.S | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1297,12 +1297,13 @@ ENTRY(nmi) movq %rax, %cr3 #endif call do_nmi + +#ifdef CONFIG_KAISER /* * Unconditionally restore CR3. I know we return to * kernel code that needs user CR3, but do we ever return * to "user mode" where we need the kernel CR3? */ -#ifdef CONFIG_KAISER popq %rax mov %rax, %cr3 #endif @@ -1526,6 +1527,8 @@ end_repeat_nmi: SWAPGS xorl %ebx, %ebx 1: + movq %rsp, %rdi + movq $-1, %rsi #ifdef CONFIG_KAISER /* Unconditionally use kernel CR3 for do_nmi() */ /* %rax is saved above, so OK to clobber here */ @@ -1538,16 +1541,14 @@ end_repeat_nmi: #endif /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ - movq %rsp, %rdi - addq $8, %rdi /* point %rdi at ptregs, fixed up for CR3 */ - movq $-1, %rsi call do_nmi + +#ifdef CONFIG_KAISER /* * Unconditionally restore CR3. We might be returning to * kernel code that needs user CR3, like just just before * a sysret. */ -#ifdef CONFIG_KAISER popq %rax mov %rax, %cr3 #endif