diff options
Diffstat (limited to 'include/asm-x86_64/alternative.h')
| -rw-r--r-- | include/asm-x86_64/alternative.h | 70 |
1 files changed, 37 insertions, 33 deletions
diff --git a/include/asm-x86_64/alternative.h b/include/asm-x86_64/alternative.h index a09427640764..ab161e810151 100644 --- a/include/asm-x86_64/alternative.h +++ b/include/asm-x86_64/alternative.h @@ -5,6 +5,41 @@ #include <linux/types.h> #include <linux/stddef.h> + +/* + * Alternative inline assembly for SMP. + * + * The LOCK_PREFIX macro defined here replaces the LOCK and + * LOCK_PREFIX macros used everywhere in the source tree. + * + * SMP alternatives use the same data structures as the other + * alternatives and the X86_FEATURE_UP flag to indicate the case of a + * UP system running a SMP kernel. The existing apply_alternatives() + * works fine for patching a SMP kernel for UP. + * + * The SMP alternative tables can be kept after boot and contain both + * UP and SMP versions of the instructions to allow switching back to + * SMP at runtime, when hotplugging in a new CPU, which is especially + * useful in virtualized environments. + * + * The very common lock prefix is handled as special case in a + * separate table which is a pure address list without replacement ptr + * and size information. That keeps the table sizes small. + */ + +#ifdef CONFIG_SMP +#define LOCK_PREFIX \ + ".section .smp_locks,\"a\"\n" \ + " .align 8\n" \ + " .quad 661f\n" /* address */ \ + ".previous\n" \ + "661:\n\tlock; " + +#else /* ! CONFIG_SMP */ +#define LOCK_PREFIX "" +#endif + +/* This must be included *after* the definition of LOCK_PREFIX */ #include <asm/cpufeature.h> struct alt_instr { @@ -108,39 +143,6 @@ static inline void alternatives_smp_switch(int smp) {} */ #define ASM_OUTPUT2(a, b) a, b -/* - * Alternative inline assembly for SMP. - * - * The LOCK_PREFIX macro defined here replaces the LOCK and - * LOCK_PREFIX macros used everywhere in the source tree. - * - * SMP alternatives use the same data structures as the other - * alternatives and the X86_FEATURE_UP flag to indicate the case of a - * UP system running a SMP kernel. The existing apply_alternatives() - * works fine for patching a SMP kernel for UP. - * - * The SMP alternative tables can be kept after boot and contain both - * UP and SMP versions of the instructions to allow switching back to - * SMP at runtime, when hotplugging in a new CPU, which is especially - * useful in virtualized environments. - * - * The very common lock prefix is handled as special case in a - * separate table which is a pure address list without replacement ptr - * and size information. That keeps the table sizes small. - */ - -#ifdef CONFIG_SMP -#define LOCK_PREFIX \ - ".section .smp_locks,\"a\"\n" \ - " .align 8\n" \ - " .quad 661f\n" /* address */ \ - ".previous\n" \ - "661:\n\tlock; " - -#else /* ! CONFIG_SMP */ -#define LOCK_PREFIX "" -#endif - struct paravirt_patch; #ifdef CONFIG_PARAVIRT void apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end); @@ -152,4 +154,6 @@ apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end) #define __parainstructions_end NULL #endif +extern void text_poke(void *addr, unsigned char *opcode, int len); + #endif /* _X86_64_ALTERNATIVE_H */ |