44 lines
1.3 KiB
C
44 lines
1.3 KiB
C
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#ifndef __ASM_ALTERNATIVE_H
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#define __ASM_ALTERNATIVE_H
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#include <linux/types.h>
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#include <linux/stddef.h>
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#include <linux/stringify.h>
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struct alt_instr {
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s32 orig_offset; /* offset to original instruction */
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s32 alt_offset; /* offset to replacement instruction */
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u16 cpufeature; /* cpufeature bit set for replacement */
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u8 orig_len; /* size of original instruction(s) */
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u8 alt_len; /* size of new instruction(s), <= orig_len */
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};
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void apply_alternatives(void);
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void free_alternatives_memory(void);
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#define ALTINSTR_ENTRY(feature) \
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" .word 661b - .\n" /* label */ \
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" .word 663f - .\n" /* new instruction */ \
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" .hword " __stringify(feature) "\n" /* feature bit */ \
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" .byte 662b-661b\n" /* source len */ \
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" .byte 664f-663f\n" /* replacement len */
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/* alternative assembly primitive: */
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#define ALTERNATIVE(oldinstr, newinstr, feature) \
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"661:\n\t" \
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oldinstr "\n" \
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"662:\n" \
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".pushsection .altinstructions,\"a\"\n" \
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ALTINSTR_ENTRY(feature) \
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".popsection\n" \
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".pushsection .altinstr_replacement, \"a\"\n" \
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"663:\n\t" \
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newinstr "\n" \
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"664:\n\t" \
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".popsection\n\t" \
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".if ((664b-663b) != (662b-661b))\n\t" \
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" .error \"Alternatives instruction length mismatch\"\n\t"\
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".endif\n"
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#endif /* __ASM_ALTERNATIVE_H */
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