name : alternative-asm.h /* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_ALTERNATIVE_ASM_H #define _ASM_ALTERNATIVE_ASM_H #ifdef __ASSEMBLY__ #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 /* __ASSEMBLY__ */ #endif /* _ASM_ALTERNATIVE_ASM_H */