1 #ifndef _I386_ALTERNATIVE_H 2 #define _I386_ALTERNATIVE_H 3 4 #include <asm/types.h> 5 #include <linux/stddef.h> 6 #include <linux/types.h> 7 8 struct alt_instr { 9 u8 *instr; /* original instruction */ 10 u8 *replacement; 11 u8 cpuid; /* cpuid bit set for replacement */ 12 u8 instrlen; /* length of original instruction */ 13 u8 replacementlen; /* length of new instruction, <= instrlen */ 14 u8 pad; 15 }; 16 17 extern void alternative_instructions(void); 18 extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end); 19 20 struct module; 21 #ifdef CONFIG_SMP 22 extern void alternatives_smp_module_add(struct module *mod, char *name, 23 void *locks, void *locks_end, 24 void *text, void *text_end); 25 extern void alternatives_smp_module_del(struct module *mod); 26 extern void alternatives_smp_switch(int smp); 27 #else 28 static inline void alternatives_smp_module_add(struct module *mod, char *name, 29 void *locks, void *locks_end, 30 void *text, void *text_end) {} 31 static inline void alternatives_smp_module_del(struct module *mod) {} 32 static inline void alternatives_smp_switch(int smp) {} 33 #endif /* CONFIG_SMP */ 34 35 /* 36 * Alternative instructions for different CPU types or capabilities. 37 * 38 * This allows to use optimized instructions even on generic binary 39 * kernels. 40 * 41 * length of oldinstr must be longer or equal the length of newinstr 42 * It can be padded with nops as needed. 43 * 44 * For non barrier like inlines please define new variants 45 * without volatile and memory clobber. 46 */ 47 #define alternative(oldinstr, newinstr, feature) \ 48 asm volatile ("661:\n\t" oldinstr "\n662:\n" \ 49 ".section .altinstructions,\"a\"\n" \ 50 " .align 4\n" \ 51 " .long 661b\n" /* label */ \ 52 " .long 663f\n" /* new instruction */ \ 53 " .byte %c0\n" /* feature bit */ \ 54 " .byte 662b-661b\n" /* sourcelen */ \ 55 " .byte 664f-663f\n" /* replacementlen */ \ 56 ".previous\n" \ 57 ".section .altinstr_replacement,\"ax\"\n" \ 58 "663:\n\t" newinstr "\n664:\n" /* replacement */\ 59 ".previous" :: "i" (feature) : "memory") 60 61 /* 62 * Alternative inline assembly with input. 63 * 64 * Pecularities: 65 * No memory clobber here. 66 * Argument numbers start with 1. 67 * Best is to use constraints that are fixed size (like (%1) ... "r") 68 * If you use variable sized constraints like "m" or "g" in the 69 * replacement maake sure to pad to the worst case length. 70 */ 71 #define alternative_input(oldinstr, newinstr, feature, input...) \ 72 asm volatile ("661:\n\t" oldinstr "\n662:\n" \ 73 ".section .altinstructions,\"a\"\n" \ 74 " .align 4\n" \ 75 " .long 661b\n" /* label */ \ 76 " .long 663f\n" /* new instruction */ \ 77 " .byte %c0\n" /* feature bit */ \ 78 " .byte 662b-661b\n" /* sourcelen */ \ 79 " .byte 664f-663f\n" /* replacementlen */ \ 80 ".previous\n" \ 81 ".section .altinstr_replacement,\"ax\"\n" \ 82 "663:\n\t" newinstr "\n664:\n" /* replacement */\ 83 ".previous" :: "i" (feature), ##input) 84 85 /* Like alternative_input, but with a single output argument */ 86 #define alternative_io(oldinstr, newinstr, feature, output, input...) \ 87 asm volatile ("661:\n\t" oldinstr "\n662:\n" \ 88 ".section .altinstructions,\"a\"\n" \ 89 " .align 4\n" \ 90 " .long 661b\n" /* label */ \ 91 " .long 663f\n" /* new instruction */ \ 92 " .byte %c[feat]\n" /* feature bit */ \ 93 " .byte 662b-661b\n" /* sourcelen */ \ 94 " .byte 664f-663f\n" /* replacementlen */ \ 95 ".previous\n" \ 96 ".section .altinstr_replacement,\"ax\"\n" \ 97 "663:\n\t" newinstr "\n664:\n" /* replacement */ \ 98 ".previous" : output : [feat] "i" (feature), ##input) 99 100 /* 101 * use this macro(s) if you need more than one output parameter 102 * in alternative_io 103 */ 104 #define ASM_OUTPUT2(a, b) a, b 105 106 /* 107 * Alternative inline assembly for SMP. 108 * 109 * The LOCK_PREFIX macro defined here replaces the LOCK and 110 * LOCK_PREFIX macros used everywhere in the source tree. 111 * 112 * SMP alternatives use the same data structures as the other 113 * alternatives and the X86_FEATURE_UP flag to indicate the case of a 114 * UP system running a SMP kernel. The existing apply_alternatives() 115 * works fine for patching a SMP kernel for UP. 116 * 117 * The SMP alternative tables can be kept after boot and contain both 118 * UP and SMP versions of the instructions to allow switching back to 119 * SMP at runtime, when hotplugging in a new CPU, which is especially 120 * useful in virtualized environments. 121 * 122 * The very common lock prefix is handled as special case in a 123 * separate table which is a pure address list without replacement ptr 124 * and size information. That keeps the table sizes small. 125 */ 126 127 #ifdef CONFIG_SMP 128 #define LOCK_PREFIX \ 129 ".section .smp_locks,\"a\"\n" \ 130 " .align 4\n" \ 131 " .long 661f\n" /* address */ \ 132 ".previous\n" \ 133 "661:\n\tlock; " 134 135 #else /* ! CONFIG_SMP */ 136 #define LOCK_PREFIX "" 137 #endif 138 139 struct paravirt_patch_site; 140 #ifdef CONFIG_PARAVIRT 141 void apply_paravirt(struct paravirt_patch_site *start, 142 struct paravirt_patch_site *end); 143 #else 144 static inline void 145 apply_paravirt(struct paravirt_patch_site *start, 146 struct paravirt_patch_site *end) 147 {} 148 #define __parainstructions NULL 149 #define __parainstructions_end NULL 150 #endif 151 152 extern void text_poke(void *addr, unsigned char *opcode, int len); 153 154 #endif /* _I386_ALTERNATIVE_H */ 155
