From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752430AbaLFRyy (ORCPT ); Sat, 6 Dec 2014 12:54:54 -0500 Received: from 1wt.eu ([62.212.114.60]:40692 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752169AbaLFRyu (ORCPT ); Sat, 6 Dec 2014 12:54:50 -0500 Message-Id: <20141206174148.502715555@1wt.eu> User-Agent: quilt/0.63-1 Date: Sat, 06 Dec 2014 18:41:50 +0100 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Brian Gerst , Linus Torvalds , Jan Beulich , Ingo Molnar , Willy Tarreau Subject: [ 02/25] x86, 64-bit: Move K8 B step iret fixup to fault entry asm MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 In-Reply-To: <2a26e912d2438674771c36169c190830@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Brian Gerst Move the handling of truncated %rip from an iret fault to the fault entry path. This allows x86-64 to use the standard search_extable() function. Signed-off-by: Brian Gerst Cc: Linus Torvalds Cc: Jan Beulich LKML-Reference: <1255357103-5418-1-git-send-email-brgerst@gmail.com> Signed-off-by: Ingo Molnar (cherry picked from commit ae24ffe5ecec17c956ac25371d7c2e12b4b36e53) [wt: only merged to fix patch context and ease merging of next patches] Signed-off-by: Willy Tarreau --- arch/x86/include/asm/uaccess.h | 1 - arch/x86/kernel/entry_64.S | 11 ++++++++--- arch/x86/mm/extable.c | 31 ------------------------------- 3 files changed, 8 insertions(+), 35 deletions(-) diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 61c5874..99f0ad7 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -570,7 +570,6 @@ extern struct movsl_mask { #ifdef CONFIG_X86_32 # include "uaccess_32.h" #else -# define ARCH_HAS_SEARCH_EXTABLE # include "uaccess_64.h" #endif diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 34a56a9..4f577eb 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -1491,12 +1491,17 @@ error_kernelspace: leaq irq_return(%rip),%rcx cmpq %rcx,RIP+8(%rsp) je error_swapgs - movl %ecx,%ecx /* zero extend */ - cmpq %rcx,RIP+8(%rsp) - je error_swapgs + movl %ecx,%eax /* zero extend */ + cmpq %rax,RIP+8(%rsp) + je bstep_iret cmpq $gs_change,RIP+8(%rsp) je error_swapgs jmp error_sti + +bstep_iret: + /* Fix truncated RIP */ + movq %rcx,RIP+8(%rsp) + je error_swapgs END(error_entry) diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c index 61b41ca..d0474ad 100644 --- a/arch/x86/mm/extable.c +++ b/arch/x86/mm/extable.c @@ -35,34 +35,3 @@ int fixup_exception(struct pt_regs *regs) return 0; } - -#ifdef CONFIG_X86_64 -/* - * Need to defined our own search_extable on X86_64 to work around - * a B stepping K8 bug. - */ -const struct exception_table_entry * -search_extable(const struct exception_table_entry *first, - const struct exception_table_entry *last, - unsigned long value) -{ - /* B stepping K8 bug */ - if ((value >> 32) == 0) - value |= 0xffffffffUL << 32; - - while (first <= last) { - const struct exception_table_entry *mid; - long diff; - - mid = (last - first) / 2 + first; - diff = mid->insn - value; - if (diff == 0) - return mid; - else if (diff < 0) - first = mid+1; - else - last = mid-1; - } - return NULL; -} -#endif -- 1.7.12.2.21.g234cd45.dirty