From ae24ffe5ecec17c956ac25371d7c2e12b4b36e53 Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Mon, 12 Oct 2009 10:18:23 -0400 Subject: [PATCH] x86, 64-bit: Move K8 B step iret fixup to fault entry asm 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 --- 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 d2c6c930b491..abd3e0ea762a 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 b5c061f8f358..af0f4b226dbe 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 61b41ca3b5a2..d0474ad2a6e5 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 -- 2.20.1