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Commit ae24ffe5 authored by Brian Gerst's avatar Brian Gerst Committed by Ingo Molnar
Browse files

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: default avatarBrian Gerst <brgerst@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <1255357103-5418-1-git-send-email-brgerst@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent f3834b9e

arch/x86/include/asm/uaccess.h

+0 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/entry_64.S

+8 −3
Original line number Diff line number Diff line
@@ -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)

arch/x86/mm/extable.c

+0 −31
Original line number Diff line number Diff line
@@ -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