diff options
Diffstat (limited to 'arch/loongarch/include/asm/alternative-asm.h')
| -rw-r--r-- | arch/loongarch/include/asm/alternative-asm.h | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/arch/loongarch/include/asm/alternative-asm.h b/arch/loongarch/include/asm/alternative-asm.h new file mode 100644 index 000000000000..ff3d10ac393f --- /dev/null +++ b/arch/loongarch/include/asm/alternative-asm.h @@ -0,0 +1,82 @@ +/* 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 */ |