b6a68a16dc
This avoids confusing the disassembler. Costs 2 bytes per BUG. Thanks to Suresh Siddha and Jan Beulich for suggesting suitable instructions. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
36 lines
957 B
C
36 lines
957 B
C
#ifndef __ASM_X8664_BUG_H
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#define __ASM_X8664_BUG_H 1
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#include <linux/stringify.h>
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/*
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* Tell the user there is some problem. The exception handler decodes
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* this frame.
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*/
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struct bug_frame {
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unsigned char ud2[2];
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unsigned char mov;
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/* should use 32bit offset instead, but the assembler doesn't
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like it */
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char *filename;
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unsigned char ret;
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unsigned short line;
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} __attribute__((packed));
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#ifdef CONFIG_BUG
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#define HAVE_ARCH_BUG
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/* We turn the bug frame into valid instructions to not confuse
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the disassembler. Thanks to Jan Beulich & Suresh Siddha
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for nice instruction selection.
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The magic numbers generate mov $64bitimm,%eax ; ret $offset. */
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#define BUG() \
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asm volatile( \
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"ud2 ; .byte 0xa3 ; .quad %c1 ; .byte 0xc2 ; .short %c0" :: \
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"i"(__LINE__), "i" (__stringify(__FILE__)))
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void out_of_line_bug(void);
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#else
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static inline void out_of_line_bug(void) { }
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#endif
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#include <asm-generic/bug.h>
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#endif
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