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- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef _ASM_ALTERNATIVE_ASM_H
- #define _ASM_ALTERNATIVE_ASM_H
- #ifdef __ASSEMBLER__
- #include <asm/asm.h>
- /*
- * Issue one struct alt_instr descriptor entry (need to put it into
- * the section .altinstructions, see below). This entry contains
- * enough information for the alternatives patching code to patch an
- * instruction. See apply_alternatives().
- */
- .macro altinstruction_entry orig alt feature orig_len alt_len
- .long \orig - .
- .long \alt - .
- .short \feature
- .byte \orig_len
- .byte \alt_len
- .endm
- /*
- * Define an alternative between two instructions. If @feature is
- * present, early code in apply_alternatives() replaces @oldinstr with
- * @newinstr. ".fill" directive takes care of proper instruction padding
- * in case @newinstr is longer than @oldinstr.
- */
- .macro ALTERNATIVE oldinstr, newinstr, feature
- 140 :
- \oldinstr
- 141 :
- .fill - (((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)) / 4, 4, 0x03400000
- 142 :
- .pushsection .altinstructions, "a"
- altinstruction_entry 140b, 143f, \feature, 142b-140b, 144f-143f
- .popsection
- .subsection 1
- 143 :
- \newinstr
- 144 :
- .previous
- .endm
- #define old_len (141b-140b)
- #define new_len1 (144f-143f)
- #define new_len2 (145f-144f)
- #define alt_max_short(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b)))))
- /*
- * Same as ALTERNATIVE macro above but for two alternatives. If CPU
- * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
- * @feature2, it replaces @oldinstr with @feature2.
- */
- .macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
- 140 :
- \oldinstr
- 141 :
- .fill - ((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \
- (alt_max_short(new_len1, new_len2) - (old_len)) / 4, 4, 0x03400000
- 142 :
- .pushsection .altinstructions, "a"
- altinstruction_entry 140b, 143f, \feature1, 142b-140b, 144f-143f, 142b-141b
- altinstruction_entry 140b, 144f, \feature2, 142b-140b, 145f-144f, 142b-141b
- .popsection
- .subsection 1
- 143 :
- \newinstr1
- 144 :
- \newinstr2
- 145 :
- .previous
- .endm
- #endif /* __ASSEMBLER__ */
- #endif /* _ASM_ALTERNATIVE_ASM_H */
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