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548acf1923
Huge amounts of help from Andy Lutomirski and Borislav Petkov to
produce this. Andy provided the inspiration to add classes to the
exception table with a clever bit-squeezing trick, Boris pointed
out how much cleaner it would all be if we just had a new field.
Linus Torvalds blessed the expansion with:
' I'd rather not be clever in order to save just a tiny amount of space
in the exception table, which isn't really criticial for anybody. '
The third field is another relative function pointer, this one to a
handler that executes the actions.
We start out with three handlers:
1: Legacy - just jumps the to fixup IP
2: Fault - provide the trap number in %ax to the fixup code
3: Cleaned up legacy for the uaccess error hack
Signed-off-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f6af78fcbd348cf4939875cfda9c19689b5e50b8.1455732970.git.tony.luck@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
117 lines
2.9 KiB
C
117 lines
2.9 KiB
C
#ifndef _ASM_X86_ASM_H
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#define _ASM_X86_ASM_H
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#ifdef __ASSEMBLY__
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# define __ASM_FORM(x) x
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# define __ASM_FORM_RAW(x) x
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# define __ASM_FORM_COMMA(x) x,
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#else
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# define __ASM_FORM(x) " " #x " "
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# define __ASM_FORM_RAW(x) #x
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# define __ASM_FORM_COMMA(x) " " #x ","
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#endif
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#ifdef CONFIG_X86_32
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# define __ASM_SEL(a,b) __ASM_FORM(a)
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# define __ASM_SEL_RAW(a,b) __ASM_FORM_RAW(a)
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#else
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# define __ASM_SEL(a,b) __ASM_FORM(b)
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# define __ASM_SEL_RAW(a,b) __ASM_FORM_RAW(b)
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#endif
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#define __ASM_SIZE(inst, ...) __ASM_SEL(inst##l##__VA_ARGS__, \
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inst##q##__VA_ARGS__)
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#define __ASM_REG(reg) __ASM_SEL_RAW(e##reg, r##reg)
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#define _ASM_PTR __ASM_SEL(.long, .quad)
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#define _ASM_ALIGN __ASM_SEL(.balign 4, .balign 8)
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#define _ASM_MOV __ASM_SIZE(mov)
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#define _ASM_INC __ASM_SIZE(inc)
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#define _ASM_DEC __ASM_SIZE(dec)
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#define _ASM_ADD __ASM_SIZE(add)
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#define _ASM_SUB __ASM_SIZE(sub)
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#define _ASM_XADD __ASM_SIZE(xadd)
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#define _ASM_AX __ASM_REG(ax)
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#define _ASM_BX __ASM_REG(bx)
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#define _ASM_CX __ASM_REG(cx)
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#define _ASM_DX __ASM_REG(dx)
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#define _ASM_SP __ASM_REG(sp)
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#define _ASM_BP __ASM_REG(bp)
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#define _ASM_SI __ASM_REG(si)
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#define _ASM_DI __ASM_REG(di)
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/* Exception table entry */
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#ifdef __ASSEMBLY__
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# define _ASM_EXTABLE_HANDLE(from, to, handler) \
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.pushsection "__ex_table","a" ; \
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.balign 4 ; \
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.long (from) - . ; \
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.long (to) - . ; \
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.long (handler) - . ; \
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.popsection
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# define _ASM_EXTABLE(from, to) \
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_ASM_EXTABLE_HANDLE(from, to, ex_handler_default)
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# define _ASM_EXTABLE_FAULT(from, to) \
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_ASM_EXTABLE_HANDLE(from, to, ex_handler_fault)
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# define _ASM_EXTABLE_EX(from, to) \
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_ASM_EXTABLE_HANDLE(from, to, ex_handler_ext)
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# define _ASM_NOKPROBE(entry) \
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.pushsection "_kprobe_blacklist","aw" ; \
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_ASM_ALIGN ; \
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_ASM_PTR (entry); \
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.popsection
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.macro ALIGN_DESTINATION
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/* check for bad alignment of destination */
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movl %edi,%ecx
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andl $7,%ecx
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jz 102f /* already aligned */
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subl $8,%ecx
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negl %ecx
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subl %ecx,%edx
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100: movb (%rsi),%al
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101: movb %al,(%rdi)
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incq %rsi
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incq %rdi
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decl %ecx
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jnz 100b
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102:
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.section .fixup,"ax"
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103: addl %ecx,%edx /* ecx is zerorest also */
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jmp copy_user_handle_tail
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.previous
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_ASM_EXTABLE(100b,103b)
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_ASM_EXTABLE(101b,103b)
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.endm
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#else
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# define _EXPAND_EXTABLE_HANDLE(x) #x
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# define _ASM_EXTABLE_HANDLE(from, to, handler) \
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" .pushsection \"__ex_table\",\"a\"\n" \
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" .balign 4\n" \
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" .long (" #from ") - .\n" \
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" .long (" #to ") - .\n" \
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" .long (" _EXPAND_EXTABLE_HANDLE(handler) ") - .\n" \
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" .popsection\n"
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# define _ASM_EXTABLE(from, to) \
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_ASM_EXTABLE_HANDLE(from, to, ex_handler_default)
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# define _ASM_EXTABLE_FAULT(from, to) \
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_ASM_EXTABLE_HANDLE(from, to, ex_handler_fault)
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# define _ASM_EXTABLE_EX(from, to) \
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_ASM_EXTABLE_HANDLE(from, to, ex_handler_ext)
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/* For C file, we already have NOKPROBE_SYMBOL macro */
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#endif
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#endif /* _ASM_X86_ASM_H */
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