diff options
Diffstat (limited to 'arch/x86/include/asm/alternative.h')
| -rw-r--r-- | arch/x86/include/asm/alternative.h | 149 |
1 files changed, 132 insertions, 17 deletions
diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 13adca37c99a..a3c2315aca12 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -2,13 +2,17 @@ #ifndef _ASM_X86_ALTERNATIVE_H #define _ASM_X86_ALTERNATIVE_H -#ifndef __ASSEMBLY__ - #include <linux/types.h> -#include <linux/stddef.h> #include <linux/stringify.h> #include <asm/asm.h> +#define ALTINSTR_FLAG_INV (1 << 15) +#define ALT_NOT(feat) ((feat) | ALTINSTR_FLAG_INV) + +#ifndef __ASSEMBLY__ + +#include <linux/stddef.h> + /* * Alternative inline assembly for SMP. * @@ -61,7 +65,6 @@ struct alt_instr { u16 cpuid; /* cpuid bit set for replacement */ u8 instrlen; /* length of original instruction */ u8 replacementlen; /* length of new instruction */ - u8 padlen; /* length of build-time padding */ } __packed; /* @@ -100,7 +103,6 @@ static inline int alternatives_text_reserved(void *start, void *end) #define alt_end_marker "663" #define alt_slen "662b-661b" -#define alt_pad_len alt_end_marker"b-662b" #define alt_total_slen alt_end_marker"b-661b" #define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f" @@ -147,10 +149,9 @@ static inline int alternatives_text_reserved(void *start, void *end) " .long " b_replacement(num)"f - .\n" /* new instruction */ \ " .word " __stringify(feature) "\n" /* feature bit */ \ " .byte " alt_total_slen "\n" /* source len */ \ - " .byte " alt_rlen(num) "\n" /* replacement len */ \ - " .byte " alt_pad_len "\n" /* pad len */ + " .byte " alt_rlen(num) "\n" /* replacement len */ -#define ALTINSTR_REPLACEMENT(newinstr, feature, num) /* replacement */ \ +#define ALTINSTR_REPLACEMENT(newinstr, num) /* replacement */ \ "# ALT: replacement " #num "\n" \ b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n" @@ -161,7 +162,7 @@ static inline int alternatives_text_reserved(void *start, void *end) ALTINSTR_ENTRY(feature, 1) \ ".popsection\n" \ ".pushsection .altinstr_replacement, \"ax\"\n" \ - ALTINSTR_REPLACEMENT(newinstr, feature, 1) \ + ALTINSTR_REPLACEMENT(newinstr, 1) \ ".popsection\n" #define ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)\ @@ -171,10 +172,15 @@ static inline int alternatives_text_reserved(void *start, void *end) ALTINSTR_ENTRY(feature2, 2) \ ".popsection\n" \ ".pushsection .altinstr_replacement, \"ax\"\n" \ - ALTINSTR_REPLACEMENT(newinstr1, feature1, 1) \ - ALTINSTR_REPLACEMENT(newinstr2, feature2, 2) \ + ALTINSTR_REPLACEMENT(newinstr1, 1) \ + ALTINSTR_REPLACEMENT(newinstr2, 2) \ ".popsection\n" +/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ +#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \ + ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ + newinstr_yes, feature) + #define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \ OLDINSTR_3(oldinsn, 1, 2, 3) \ ".pushsection .altinstructions,\"a\"\n" \ @@ -183,9 +189,9 @@ static inline int alternatives_text_reserved(void *start, void *end) ALTINSTR_ENTRY(feat3, 3) \ ".popsection\n" \ ".pushsection .altinstr_replacement, \"ax\"\n" \ - ALTINSTR_REPLACEMENT(newinsn1, feat1, 1) \ - ALTINSTR_REPLACEMENT(newinsn2, feat2, 2) \ - ALTINSTR_REPLACEMENT(newinsn3, feat3, 3) \ + ALTINSTR_REPLACEMENT(newinsn1, 1) \ + ALTINSTR_REPLACEMENT(newinsn2, 2) \ + ALTINSTR_REPLACEMENT(newinsn3, 3) \ ".popsection\n" /* @@ -206,15 +212,15 @@ static inline int alternatives_text_reserved(void *start, void *end) #define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \ asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory") +#define alternative_ternary(oldinstr, feature, newinstr_yes, newinstr_no) \ + asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) ::: "memory") + /* * Alternative inline assembly with input. * * Peculiarities: * No memory clobber here. * Argument numbers start with 1. - * Best is to use constraints that are fixed size (like (%1) ... "r") - * If you use variable sized constraints like "m" or "g" in the - * replacement make sure to pad to the worst case length. * Leaving an unused argument 0 to keep API compatibility. */ #define alternative_input(oldinstr, newinstr, feature, input...) \ @@ -271,6 +277,115 @@ static inline int alternatives_text_reserved(void *start, void *end) */ #define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr +#else /* __ASSEMBLY__ */ + +#ifdef CONFIG_SMP + .macro LOCK_PREFIX +672: lock + .pushsection .smp_locks,"a" + .balign 4 + .long 672b - . + .popsection + .endm +#else + .macro LOCK_PREFIX + .endm +#endif + +/* + * objtool annotation to ignore the alternatives and only consider the original + * instruction(s). + */ +.macro ANNOTATE_IGNORE_ALTERNATIVE + .Lannotate_\@: + .pushsection .discard.ignore_alts + .long .Lannotate_\@ - . + .popsection +.endm + +/* + * 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 - . + .word \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. ".skip" directive takes care of proper instruction padding + * in case @newinstr is longer than @oldinstr. + */ +.macro ALTERNATIVE oldinstr, newinstr, feature +140: + \oldinstr +141: + .skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90 +142: + + .pushsection .altinstructions,"a" + altinstruction_entry 140b,143f,\feature,142b-140b,144f-143f + .popsection + + .pushsection .altinstr_replacement,"ax" +143: + \newinstr +144: + .popsection +.endm + +#define old_len 141b-140b +#define new_len1 144f-143f +#define new_len2 145f-144f + +/* + * gas compatible max based on the idea from: + * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax + * + * The additional "-" is needed because gas uses a "true" value of -1. + */ +#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: + .skip -((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \ + (alt_max_short(new_len1, new_len2) - (old_len)),0x90 +142: + + .pushsection .altinstructions,"a" + altinstruction_entry 140b,143f,\feature1,142b-140b,144f-143f + altinstruction_entry 140b,144f,\feature2,142b-140b,145f-144f + .popsection + + .pushsection .altinstr_replacement,"ax" +143: + \newinstr1 +144: + \newinstr2 +145: + .popsection +.endm + +/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ +#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \ + ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ + newinstr_yes, feature + #endif /* __ASSEMBLY__ */ #endif /* _ASM_X86_ALTERNATIVE_H */ |