| .. | .. |
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| 2 | 2 | #ifndef _ASM_X86_ALTERNATIVE_H |
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| 3 | 3 | #define _ASM_X86_ALTERNATIVE_H |
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| 4 | 4 | |
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| 5 | | -#ifndef __ASSEMBLY__ |
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| 6 | | - |
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| 7 | 5 | #include <linux/types.h> |
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| 8 | | -#include <linux/stddef.h> |
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| 9 | 6 | #include <linux/stringify.h> |
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| 10 | 7 | #include <asm/asm.h> |
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| 8 | + |
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| 9 | +#define ALTINSTR_FLAG_INV (1 << 15) |
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| 10 | +#define ALT_NOT(feat) ((feat) | ALTINSTR_FLAG_INV) |
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| 11 | + |
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| 12 | +#ifndef __ASSEMBLY__ |
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| 13 | + |
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| 14 | +#include <linux/stddef.h> |
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| 11 | 15 | |
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| 12 | 16 | /* |
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| 13 | 17 | * Alternative inline assembly for SMP. |
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| .. | .. |
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| 45 | 49 | #define LOCK_PREFIX "" |
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| 46 | 50 | #endif |
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| 47 | 51 | |
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| 52 | +/* |
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| 53 | + * objtool annotation to ignore the alternatives and only consider the original |
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| 54 | + * instruction(s). |
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| 55 | + */ |
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| 56 | +#define ANNOTATE_IGNORE_ALTERNATIVE \ |
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| 57 | + "999:\n\t" \ |
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| 58 | + ".pushsection .discard.ignore_alts\n\t" \ |
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| 59 | + ".long 999b - .\n\t" \ |
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| 60 | + ".popsection\n\t" |
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| 61 | + |
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| 48 | 62 | struct alt_instr { |
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| 49 | 63 | s32 instr_offset; /* original instruction */ |
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| 50 | 64 | s32 repl_offset; /* offset to replacement instruction */ |
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| 51 | 65 | u16 cpuid; /* cpuid bit set for replacement */ |
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| 52 | 66 | u8 instrlen; /* length of original instruction */ |
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| 53 | 67 | u8 replacementlen; /* length of new instruction */ |
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| 54 | | - u8 padlen; /* length of build-time padding */ |
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| 55 | 68 | } __packed; |
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| 56 | 69 | |
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| 57 | 70 | /* |
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| .. | .. |
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| 62 | 75 | |
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| 63 | 76 | extern void alternative_instructions(void); |
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| 64 | 77 | extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end); |
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| 78 | +extern void apply_retpolines(s32 *start, s32 *end); |
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| 79 | +extern void apply_returns(s32 *start, s32 *end); |
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| 65 | 80 | |
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| 66 | 81 | struct module; |
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| 67 | 82 | |
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| .. | .. |
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| 90 | 105 | |
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| 91 | 106 | #define alt_end_marker "663" |
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| 92 | 107 | #define alt_slen "662b-661b" |
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| 93 | | -#define alt_pad_len alt_end_marker"b-662b" |
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| 94 | 108 | #define alt_total_slen alt_end_marker"b-661b" |
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| 95 | 109 | #define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f" |
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| 96 | 110 | |
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| 97 | | -#define __OLDINSTR(oldinstr, num) \ |
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| 98 | | - "661:\n\t" oldinstr "\n662:\n" \ |
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| 99 | | - ".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \ |
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| 100 | | - "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" |
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| 101 | | - |
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| 102 | 111 | #define OLDINSTR(oldinstr, num) \ |
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| 103 | | - __OLDINSTR(oldinstr, num) \ |
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| 112 | + "# ALT: oldnstr\n" \ |
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| 113 | + "661:\n\t" oldinstr "\n662:\n" \ |
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| 114 | + "# ALT: padding\n" \ |
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| 115 | + ".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \ |
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| 116 | + "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" \ |
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| 104 | 117 | alt_end_marker ":\n" |
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| 105 | 118 | |
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| 106 | 119 | /* |
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| .. | .. |
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| 116 | 129 | * additionally longer than the first replacement alternative. |
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| 117 | 130 | */ |
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| 118 | 131 | #define OLDINSTR_2(oldinstr, num1, num2) \ |
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| 132 | + "# ALT: oldinstr2\n" \ |
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| 119 | 133 | "661:\n\t" oldinstr "\n662:\n" \ |
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| 134 | + "# ALT: padding2\n" \ |
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| 120 | 135 | ".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * " \ |
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| 121 | 136 | "(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n" \ |
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| 137 | + alt_end_marker ":\n" |
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| 138 | + |
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| 139 | +#define OLDINSTR_3(oldinsn, n1, n2, n3) \ |
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| 140 | + "# ALT: oldinstr3\n" \ |
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| 141 | + "661:\n\t" oldinsn "\n662:\n" \ |
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| 142 | + "# ALT: padding3\n" \ |
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| 143 | + ".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \ |
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| 144 | + " - (" alt_slen ")) > 0) * " \ |
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| 145 | + "(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \ |
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| 146 | + " - (" alt_slen ")), 0x90\n" \ |
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| 122 | 147 | alt_end_marker ":\n" |
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| 123 | 148 | |
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| 124 | 149 | #define ALTINSTR_ENTRY(feature, num) \ |
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| .. | .. |
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| 126 | 151 | " .long " b_replacement(num)"f - .\n" /* new instruction */ \ |
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| 127 | 152 | " .word " __stringify(feature) "\n" /* feature bit */ \ |
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| 128 | 153 | " .byte " alt_total_slen "\n" /* source len */ \ |
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| 129 | | - " .byte " alt_rlen(num) "\n" /* replacement len */ \ |
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| 130 | | - " .byte " alt_pad_len "\n" /* pad len */ |
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| 154 | + " .byte " alt_rlen(num) "\n" /* replacement len */ |
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| 131 | 155 | |
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| 132 | | -#define ALTINSTR_REPLACEMENT(newinstr, feature, num) /* replacement */ \ |
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| 133 | | - b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n\t" |
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| 156 | +#define ALTINSTR_REPLACEMENT(newinstr, feature, num) /* replacement */ \ |
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| 157 | + "# ALT: replacement " #num "\n" \ |
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| 158 | + b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n" |
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| 134 | 159 | |
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| 135 | 160 | /* alternative assembly primitive: */ |
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| 136 | 161 | #define ALTERNATIVE(oldinstr, newinstr, feature) \ |
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| .. | .. |
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| 153 | 178 | ALTINSTR_REPLACEMENT(newinstr2, feature2, 2) \ |
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| 154 | 179 | ".popsection\n" |
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| 155 | 180 | |
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| 181 | +/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ |
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| 182 | +#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \ |
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| 183 | + ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ |
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| 184 | + newinstr_yes, feature) |
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| 185 | + |
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| 186 | +#define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \ |
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| 187 | + OLDINSTR_3(oldinsn, 1, 2, 3) \ |
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| 188 | + ".pushsection .altinstructions,\"a\"\n" \ |
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| 189 | + ALTINSTR_ENTRY(feat1, 1) \ |
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| 190 | + ALTINSTR_ENTRY(feat2, 2) \ |
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| 191 | + ALTINSTR_ENTRY(feat3, 3) \ |
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| 192 | + ".popsection\n" \ |
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| 193 | + ".pushsection .altinstr_replacement, \"ax\"\n" \ |
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| 194 | + ALTINSTR_REPLACEMENT(newinsn1, feat1, 1) \ |
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| 195 | + ALTINSTR_REPLACEMENT(newinsn2, feat2, 2) \ |
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| 196 | + ALTINSTR_REPLACEMENT(newinsn3, feat3, 3) \ |
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| 197 | + ".popsection\n" |
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| 198 | + |
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| 156 | 199 | /* |
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| 157 | 200 | * Alternative instructions for different CPU types or capabilities. |
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| 158 | 201 | * |
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| .. | .. |
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| 166 | 209 | * without volatile and memory clobber. |
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| 167 | 210 | */ |
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| 168 | 211 | #define alternative(oldinstr, newinstr, feature) \ |
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| 169 | | - asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory") |
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| 212 | + asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory") |
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| 170 | 213 | |
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| 171 | 214 | #define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \ |
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| 172 | | - asm volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory") |
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| 215 | + asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory") |
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| 216 | + |
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| 217 | +#define alternative_ternary(oldinstr, feature, newinstr_yes, newinstr_no) \ |
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| 218 | + asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) ::: "memory") |
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| 173 | 219 | |
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| 174 | 220 | /* |
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| 175 | 221 | * Alternative inline assembly with input. |
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| 176 | 222 | * |
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| 177 | | - * Pecularities: |
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| 223 | + * Peculiarities: |
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| 178 | 224 | * No memory clobber here. |
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| 179 | 225 | * Argument numbers start with 1. |
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| 180 | | - * Best is to use constraints that are fixed size (like (%1) ... "r") |
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| 181 | | - * If you use variable sized constraints like "m" or "g" in the |
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| 182 | | - * replacement make sure to pad to the worst case length. |
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| 183 | 226 | * Leaving an unused argument 0 to keep API compatibility. |
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| 184 | 227 | */ |
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| 185 | 228 | #define alternative_input(oldinstr, newinstr, feature, input...) \ |
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| 186 | | - asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ |
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| 229 | + asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ |
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| 187 | 230 | : : "i" (0), ## input) |
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| 188 | 231 | |
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| 189 | 232 | /* |
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| .. | .. |
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| 196 | 239 | */ |
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| 197 | 240 | #define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, \ |
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| 198 | 241 | feature2, input...) \ |
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| 199 | | - asm volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \ |
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| 242 | + asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \ |
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| 200 | 243 | newinstr2, feature2) \ |
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| 201 | 244 | : : "i" (0), ## input) |
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| 202 | 245 | |
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| 203 | 246 | /* Like alternative_input, but with a single output argument */ |
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| 204 | 247 | #define alternative_io(oldinstr, newinstr, feature, output, input...) \ |
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| 205 | | - asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ |
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| 248 | + asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ |
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| 206 | 249 | : output : "i" (0), ## input) |
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| 207 | 250 | |
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| 208 | 251 | /* Like alternative_io, but for replacing a direct call with another one. */ |
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| 209 | 252 | #define alternative_call(oldfunc, newfunc, feature, output, input...) \ |
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| 210 | | - asm volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \ |
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| 253 | + asm_inline volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \ |
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| 211 | 254 | : output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input) |
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| 212 | 255 | |
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| 213 | 256 | /* |
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| .. | .. |
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| 218 | 261 | */ |
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| 219 | 262 | #define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2, \ |
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| 220 | 263 | output, input...) \ |
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| 221 | | - asm volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\ |
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| 264 | + asm_inline volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\ |
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| 222 | 265 | "call %P[new2]", feature2) \ |
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| 223 | 266 | : output, ASM_CALL_CONSTRAINT \ |
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| 224 | 267 | : [old] "i" (oldfunc), [new1] "i" (newfunc1), \ |
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| .. | .. |
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| 236 | 279 | */ |
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| 237 | 280 | #define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr |
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| 238 | 281 | |
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| 282 | +#else /* __ASSEMBLY__ */ |
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| 283 | + |
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| 284 | +#ifdef CONFIG_SMP |
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| 285 | + .macro LOCK_PREFIX |
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| 286 | +672: lock |
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| 287 | + .pushsection .smp_locks,"a" |
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| 288 | + .balign 4 |
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| 289 | + .long 672b - . |
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| 290 | + .popsection |
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| 291 | + .endm |
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| 292 | +#else |
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| 293 | + .macro LOCK_PREFIX |
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| 294 | + .endm |
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| 295 | +#endif |
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| 296 | + |
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| 297 | +/* |
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| 298 | + * objtool annotation to ignore the alternatives and only consider the original |
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| 299 | + * instruction(s). |
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| 300 | + */ |
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| 301 | +.macro ANNOTATE_IGNORE_ALTERNATIVE |
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| 302 | + .Lannotate_\@: |
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| 303 | + .pushsection .discard.ignore_alts |
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| 304 | + .long .Lannotate_\@ - . |
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| 305 | + .popsection |
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| 306 | +.endm |
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| 307 | + |
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| 308 | +/* |
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| 309 | + * Issue one struct alt_instr descriptor entry (need to put it into |
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| 310 | + * the section .altinstructions, see below). This entry contains |
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| 311 | + * enough information for the alternatives patching code to patch an |
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| 312 | + * instruction. See apply_alternatives(). |
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| 313 | + */ |
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| 314 | +.macro altinstruction_entry orig alt feature orig_len alt_len |
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| 315 | + .long \orig - . |
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| 316 | + .long \alt - . |
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| 317 | + .word \feature |
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| 318 | + .byte \orig_len |
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| 319 | + .byte \alt_len |
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| 320 | +.endm |
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| 321 | + |
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| 322 | +/* |
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| 323 | + * Define an alternative between two instructions. If @feature is |
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| 324 | + * present, early code in apply_alternatives() replaces @oldinstr with |
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| 325 | + * @newinstr. ".skip" directive takes care of proper instruction padding |
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| 326 | + * in case @newinstr is longer than @oldinstr. |
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| 327 | + */ |
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| 328 | +.macro ALTERNATIVE oldinstr, newinstr, feature |
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| 329 | +140: |
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| 330 | + \oldinstr |
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| 331 | +141: |
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| 332 | + .skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90 |
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| 333 | +142: |
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| 334 | + |
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| 335 | + .pushsection .altinstructions,"a" |
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| 336 | + altinstruction_entry 140b,143f,\feature,142b-140b,144f-143f |
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| 337 | + .popsection |
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| 338 | + |
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| 339 | + .pushsection .altinstr_replacement,"ax" |
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| 340 | +143: |
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| 341 | + \newinstr |
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| 342 | +144: |
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| 343 | + .popsection |
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| 344 | +.endm |
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| 345 | + |
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| 346 | +#define old_len 141b-140b |
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| 347 | +#define new_len1 144f-143f |
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| 348 | +#define new_len2 145f-144f |
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| 349 | + |
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| 350 | +/* |
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| 351 | + * gas compatible max based on the idea from: |
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| 352 | + * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax |
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| 353 | + * |
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| 354 | + * The additional "-" is needed because gas uses a "true" value of -1. |
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| 355 | + */ |
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| 356 | +#define alt_max_short(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b))))) |
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| 357 | + |
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| 358 | + |
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| 359 | +/* |
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| 360 | + * Same as ALTERNATIVE macro above but for two alternatives. If CPU |
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| 361 | + * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has |
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| 362 | + * @feature2, it replaces @oldinstr with @feature2. |
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| 363 | + */ |
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| 364 | +.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2 |
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| 365 | +140: |
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| 366 | + \oldinstr |
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| 367 | +141: |
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| 368 | + .skip -((alt_max_short(new_len1, new_len2) - (old_len)) > 0) * \ |
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| 369 | + (alt_max_short(new_len1, new_len2) - (old_len)),0x90 |
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| 370 | +142: |
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| 371 | + |
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| 372 | + .pushsection .altinstructions,"a" |
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| 373 | + altinstruction_entry 140b,143f,\feature1,142b-140b,144f-143f |
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| 374 | + altinstruction_entry 140b,144f,\feature2,142b-140b,145f-144f |
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| 375 | + .popsection |
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| 376 | + |
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| 377 | + .pushsection .altinstr_replacement,"ax" |
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| 378 | +143: |
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| 379 | + \newinstr1 |
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| 380 | +144: |
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| 381 | + \newinstr2 |
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| 382 | +145: |
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| 383 | + .popsection |
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| 384 | +.endm |
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| 385 | + |
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| 386 | +/* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ |
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| 387 | +#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \ |
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| 388 | + ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ |
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| 389 | + newinstr_yes, feature |
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| 390 | + |
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| 239 | 391 | #endif /* __ASSEMBLY__ */ |
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| 240 | 392 | |
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| 241 | 393 | #endif /* _ASM_X86_ALTERNATIVE_H */ |
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