diff options
Diffstat (limited to 'arch/x86/include/asm/alternative.h')
| -rw-r--r-- | arch/x86/include/asm/alternative.h | 74 |
1 files changed, 59 insertions, 15 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 49331bedc158..70780689599a 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -75,23 +75,54 @@ static inline int alternatives_text_reserved(void *start, void *end) } #endif /* CONFIG_SMP */ +#define OLDINSTR(oldinstr) "661:\n\t" oldinstr "\n662:\n" + +#define b_replacement(number) "663"#number +#define e_replacement(number) "664"#number + +#define alt_slen "662b-661b" +#define alt_rlen(number) e_replacement(number)"f-"b_replacement(number)"f" + +#define ALTINSTR_ENTRY(feature, number) \ + " .long 661b - .\n" /* label */ \ + " .long " b_replacement(number)"f - .\n" /* new instruction */ \ + " .word " __stringify(feature) "\n" /* feature bit */ \ + " .byte " alt_slen "\n" /* source len */ \ + " .byte " alt_rlen(number) "\n" /* replacement len */ + +#define DISCARD_ENTRY(number) /* rlen <= slen */ \ + " .byte 0xff + (" alt_rlen(number) ") - (" alt_slen ")\n" + +#define ALTINSTR_REPLACEMENT(newinstr, feature, number) /* replacement */ \ + b_replacement(number)":\n\t" newinstr "\n" e_replacement(number) ":\n\t" + /* alternative assembly primitive: */ #define ALTERNATIVE(oldinstr, newinstr, feature) \ - \ - "661:\n\t" oldinstr "\n662:\n" \ - ".section .altinstructions,\"a\"\n" \ - " .long 661b - .\n" /* label */ \ - " .long 663f - .\n" /* new instruction */ \ - " .word " __stringify(feature) "\n" /* feature bit */ \ - " .byte 662b-661b\n" /* sourcelen */ \ - " .byte 664f-663f\n" /* replacementlen */ \ - ".previous\n" \ - ".section .discard,\"aw\",@progbits\n" \ - " .byte 0xff + (664f-663f) - (662b-661b)\n" /* rlen <= slen */ \ - ".previous\n" \ - ".section .altinstr_replacement, \"ax\"\n" \ - "663:\n\t" newinstr "\n664:\n" /* replacement */ \ - ".previous" + OLDINSTR(oldinstr) \ + ".section .altinstructions,\"a\"\n" \ + ALTINSTR_ENTRY(feature, 1) \ + ".previous\n" \ + ".section .discard,\"aw\",@progbits\n" \ + DISCARD_ENTRY(1) \ + ".previous\n" \ + ".section .altinstr_replacement, \"ax\"\n" \ + ALTINSTR_REPLACEMENT(newinstr, feature, 1) \ + ".previous" + +#define ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)\ + OLDINSTR(oldinstr) \ + ".section .altinstructions,\"a\"\n" \ + ALTINSTR_ENTRY(feature1, 1) \ + ALTINSTR_ENTRY(feature2, 2) \ + ".previous\n" \ + ".section .discard,\"aw\",@progbits\n" \ + DISCARD_ENTRY(1) \ + DISCARD_ENTRY(2) \ + ".previous\n" \ + ".section .altinstr_replacement, \"ax\"\n" \ + ALTINSTR_REPLACEMENT(newinstr1, feature1, 1) \ + ALTINSTR_REPLACEMENT(newinstr2, feature2, 2) \ + ".previous" /* * This must be included *after* the definition of ALTERNATIVE due to @@ -140,6 +171,19 @@ static inline int alternatives_text_reserved(void *start, void *end) : output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input) /* + * Like alternative_call, but there are two features and respective functions. + * If CPU has feature2, function2 is used. + * Otherwise, if CPU has feature1, function1 is used. + * Otherwise, old function is used. + */ +#define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2, \ + output, input...) \ + asm volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\ + "call %P[new2]", feature2) \ + : output : [old] "i" (oldfunc), [new1] "i" (newfunc1), \ + [new2] "i" (newfunc2), ## input) + +/* * use this macro(s) if you need more than one output parameter * in alternative_io */ |