projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 9a0b5817 GH |
1 | #ifndef _I386_ALTERNATIVE_H |
| 2 | #define _I386_ALTERNATIVE_H | |
| 3 | ||
| 4 | #ifdef __KERNEL__ | |
| 5 | ||
| 30343d6c KS |
6 | #include <asm/types.h> |
| 7 | ||
| d167a518 GH |
8 | #include <linux/types.h> |
| 9 | ||
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10 | struct alt_instr { |
| 11 | u8 *instr; /* original instruction */ | |
| 12 | u8 *replacement; | |
| 13 | u8 cpuid; /* cpuid bit set for replacement */ | |
| 14 | u8 instrlen; /* length of original instruction */ | |
| 15 | u8 replacementlen; /* length of new instruction, <= instrlen */ | |
| 16 | u8 pad; | |
| 17 | }; | |
| 18 | ||
| 19 | extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end); | |
| 20 | ||
| 21 | struct module; | |
| 8ec4d41f | 22 | #ifdef CONFIG_SMP |
| 9a0b5817 GH |
23 | extern void alternatives_smp_module_add(struct module *mod, char *name, |
| 24 | void *locks, void *locks_end, | |
| 25 | void *text, void *text_end); | |
| 26 | extern void alternatives_smp_module_del(struct module *mod); | |
| 27 | extern void alternatives_smp_switch(int smp); | |
| 8ec4d41f GH |
28 | #else |
| 29 | static inline void alternatives_smp_module_add(struct module *mod, char *name, | |
| 30 | void *locks, void *locks_end, | |
| 31 | void *text, void *text_end) {} | |
| 32 | static inline void alternatives_smp_module_del(struct module *mod) {} | |
| 33 | static inline void alternatives_smp_switch(int smp) {} | |
| 34 | #endif | |
| 9a0b5817 GH |
35 | |
| 36 | #endif | |
| 37 | ||
| 38 | /* | |
| 39 | * Alternative instructions for different CPU types or capabilities. | |
| 40 | * | |
| 41 | * This allows to use optimized instructions even on generic binary | |
| 42 | * kernels. | |
| 43 | * | |
| 44 | * length of oldinstr must be longer or equal the length of newinstr | |
| 45 | * It can be padded with nops as needed. | |
| 46 | * | |
| 47 | * For non barrier like inlines please define new variants | |
| 48 | * without volatile and memory clobber. | |
| 49 | */ | |
| 50 | #define alternative(oldinstr, newinstr, feature) \ | |
| 51 | asm volatile ("661:\n\t" oldinstr "\n662:\n" \ | |
| 52 | ".section .altinstructions,\"a\"\n" \ | |
| 53 | " .align 4\n" \ | |
| 54 | " .long 661b\n" /* label */ \ | |
| 55 | " .long 663f\n" /* new instruction */ \ | |
| 56 | " .byte %c0\n" /* feature bit */ \ | |
| 57 | " .byte 662b-661b\n" /* sourcelen */ \ | |
| 58 | " .byte 664f-663f\n" /* replacementlen */ \ | |
| 59 | ".previous\n" \ | |
| 60 | ".section .altinstr_replacement,\"ax\"\n" \ | |
| 61 | "663:\n\t" newinstr "\n664:\n" /* replacement */\ | |
| 62 | ".previous" :: "i" (feature) : "memory") | |
| 63 | ||
| 64 | /* | |
| 65 | * Alternative inline assembly with input. | |
| 66 | * | |
| 67 | * Pecularities: | |
| 68 | * No memory clobber here. | |
| 69 | * Argument numbers start with 1. | |
| 70 | * Best is to use constraints that are fixed size (like (%1) ... "r") | |
| 71 | * If you use variable sized constraints like "m" or "g" in the | |
| 72 | * replacement maake sure to pad to the worst case length. | |
| 73 | */ | |
| 74 | #define alternative_input(oldinstr, newinstr, feature, input...) \ | |
| 75 | asm volatile ("661:\n\t" oldinstr "\n662:\n" \ | |
| 76 | ".section .altinstructions,\"a\"\n" \ | |
| 77 | " .align 4\n" \ | |
| 78 | " .long 661b\n" /* label */ \ | |
| 79 | " .long 663f\n" /* new instruction */ \ | |
| 80 | " .byte %c0\n" /* feature bit */ \ | |
| 81 | " .byte 662b-661b\n" /* sourcelen */ \ | |
| 82 | " .byte 664f-663f\n" /* replacementlen */ \ | |
| 83 | ".previous\n" \ | |
| 84 | ".section .altinstr_replacement,\"ax\"\n" \ | |
| 85 | "663:\n\t" newinstr "\n664:\n" /* replacement */\ | |
| 86 | ".previous" :: "i" (feature), ##input) | |
| 87 | ||
| 88 | /* | |
| 89 | * Alternative inline assembly for SMP. | |
| 90 | * | |
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91 | * The LOCK_PREFIX macro defined here replaces the LOCK and |
| 92 | * LOCK_PREFIX macros used everywhere in the source tree. | |
| 93 | * | |
| 94 | * SMP alternatives use the same data structures as the other | |
| 95 | * alternatives and the X86_FEATURE_UP flag to indicate the case of a | |
| 96 | * UP system running a SMP kernel. The existing apply_alternatives() | |
| 97 | * works fine for patching a SMP kernel for UP. | |
| 98 | * | |
| 99 | * The SMP alternative tables can be kept after boot and contain both | |
| 100 | * UP and SMP versions of the instructions to allow switching back to | |
| 101 | * SMP at runtime, when hotplugging in a new CPU, which is especially | |
| 102 | * useful in virtualized environments. | |
| 103 | * | |
| 104 | * The very common lock prefix is handled as special case in a | |
| 105 | * separate table which is a pure address list without replacement ptr | |
| 106 | * and size information. That keeps the table sizes small. | |
| 107 | */ | |
| 108 | ||
| 109 | #ifdef CONFIG_SMP | |
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110 | #define LOCK_PREFIX \ |
| 111 | ".section .smp_locks,\"a\"\n" \ | |
| 112 | " .align 4\n" \ | |
| 113 | " .long 661f\n" /* address */ \ | |
| 114 | ".previous\n" \ | |
| 115 | "661:\n\tlock; " | |
| 116 | ||
| 117 | #else /* ! CONFIG_SMP */ | |
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118 | #define LOCK_PREFIX "" |
| 119 | #endif | |
| 120 | ||
| 121 | #endif /* _I386_ALTERNATIVE_H */ |