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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1965aae3 PA |
2 | #ifndef _ASM_X86_ALTERNATIVE_H |
3 | #define _ASM_X86_ALTERNATIVE_H | |
6b592570 PA |
4 | |
5 | #include <linux/types.h> | |
edc953fa | 6 | #include <linux/stringify.h> |
6b592570 PA |
7 | #include <asm/asm.h> |
8 | ||
5d1dd961 BPA |
9 | #define ALT_FLAGS_SHIFT 16 |
10 | ||
c22ef568 | 11 | #define ALT_FLAG_NOT (1 << 0) |
5d1dd961 | 12 | #define ALT_NOT(feature) ((ALT_FLAG_NOT << ALT_FLAGS_SHIFT) | (feature)) |
da0fe6e6 JG |
13 | #define ALT_FLAG_DIRECT_CALL (1 << 1) |
14 | #define ALT_DIRECT_CALL(feature) ((ALT_FLAG_DIRECT_CALL << ALT_FLAGS_SHIFT) | (feature)) | |
15 | #define ALT_CALL_ALWAYS ALT_DIRECT_CALL(X86_FEATURE_ALWAYS) | |
dda7bb76 | 16 | |
5e21a3ec JG |
17 | #ifndef __ASSEMBLY__ |
18 | ||
19 | #include <linux/stddef.h> | |
20 | ||
6b592570 PA |
21 | /* |
22 | * Alternative inline assembly for SMP. | |
23 | * | |
24 | * The LOCK_PREFIX macro defined here replaces the LOCK and | |
25 | * LOCK_PREFIX macros used everywhere in the source tree. | |
26 | * | |
27 | * SMP alternatives use the same data structures as the other | |
28 | * alternatives and the X86_FEATURE_UP flag to indicate the case of a | |
29 | * UP system running a SMP kernel. The existing apply_alternatives() | |
30 | * works fine for patching a SMP kernel for UP. | |
31 | * | |
32 | * The SMP alternative tables can be kept after boot and contain both | |
33 | * UP and SMP versions of the instructions to allow switching back to | |
34 | * SMP at runtime, when hotplugging in a new CPU, which is especially | |
35 | * useful in virtualized environments. | |
36 | * | |
37 | * The very common lock prefix is handled as special case in a | |
38 | * separate table which is a pure address list without replacement ptr | |
39 | * and size information. That keeps the table sizes small. | |
40 | */ | |
41 | ||
42 | #ifdef CONFIG_SMP | |
851a4cd7 IM |
43 | #define LOCK_PREFIX_HERE \ |
44 | ".pushsection .smp_locks,\"a\"\n" \ | |
45 | ".balign 4\n" \ | |
46 | ".long 671f - .\n" /* offset */ \ | |
47 | ".popsection\n" \ | |
48 | "671:" | |
49 | ||
50 | #define LOCK_PREFIX LOCK_PREFIX_HERE "\n\tlock; " | |
51 | ||
6b592570 | 52 | #else /* ! CONFIG_SMP */ |
b701a47b | 53 | #define LOCK_PREFIX_HERE "" |
6b592570 PA |
54 | #define LOCK_PREFIX "" |
55 | #endif | |
56 | ||
ff05ab23 PZ |
57 | /* |
58 | * objtool annotation to ignore the alternatives and only consider the original | |
59 | * instruction(s). | |
60 | */ | |
61 | #define ANNOTATE_IGNORE_ALTERNATIVE \ | |
62 | "999:\n\t" \ | |
63 | ".pushsection .discard.ignore_alts\n\t" \ | |
b8ec60e1 | 64 | ".long 999b\n\t" \ |
ff05ab23 PZ |
65 | ".popsection\n\t" |
66 | ||
5d1dd961 BPA |
67 | /* |
68 | * The patching flags are part of the upper bits of the @ft_flags parameter when | |
69 | * specifying them. The split is currently like this: | |
70 | * | |
71 | * [31... flags ...16][15... CPUID feature bit ...0] | |
72 | * | |
73 | * but since this is all hidden in the macros argument being split, those fields can be | |
74 | * extended in the future to fit in a u64 or however the need arises. | |
75 | */ | |
6b592570 | 76 | struct alt_instr { |
59e97e4d AL |
77 | s32 instr_offset; /* original instruction */ |
78 | s32 repl_offset; /* offset to replacement instruction */ | |
5d1dd961 BPA |
79 | |
80 | union { | |
81 | struct { | |
82 | u32 cpuid: 16; /* CPUID bit set for replacement */ | |
83 | u32 flags: 16; /* patching control flags */ | |
84 | }; | |
85 | u32 ft_flags; | |
86 | }; | |
87 | ||
6b592570 | 88 | u8 instrlen; /* length of original instruction */ |
4332195c | 89 | u8 replacementlen; /* length of new instruction */ |
4332195c | 90 | } __packed; |
6b592570 | 91 | |
60bc276b JG |
92 | extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; |
93 | ||
5e907bb0 IM |
94 | /* |
95 | * Debug flag that can be tested to see whether alternative | |
96 | * instructions were patched in already: | |
97 | */ | |
98 | extern int alternatives_patched; | |
99 | ||
6b592570 PA |
100 | extern void alternative_instructions(void); |
101 | extern void apply_alternatives(struct alt_instr *start, struct alt_instr *end); | |
75085009 | 102 | extern void apply_retpolines(s32 *start, s32 *end); |
15e67227 | 103 | extern void apply_returns(s32 *start, s32 *end); |
be0fffa5 | 104 | extern void apply_seal_endbr(s32 *start, s32 *end); |
931ab636 PZ |
105 | extern void apply_fineibt(s32 *start_retpoline, s32 *end_retpoine, |
106 | s32 *start_cfi, s32 *end_cfi); | |
6b592570 PA |
107 | |
108 | struct module; | |
e81dc127 TG |
109 | |
110 | struct callthunk_sites { | |
111 | s32 *call_start, *call_end; | |
60bc276b | 112 | struct alt_instr *alt_start, *alt_end; |
e81dc127 TG |
113 | }; |
114 | ||
115 | #ifdef CONFIG_CALL_THUNKS | |
116 | extern void callthunks_patch_builtin_calls(void); | |
eaf44c81 TG |
117 | extern void callthunks_patch_module_calls(struct callthunk_sites *sites, |
118 | struct module *mod); | |
7825451f | 119 | extern void *callthunks_translate_call_dest(void *dest); |
b2e9dfe5 | 120 | extern int x86_call_depth_emit_accounting(u8 **pprog, void *func); |
e81dc127 TG |
121 | #else |
122 | static __always_inline void callthunks_patch_builtin_calls(void) {} | |
eaf44c81 TG |
123 | static __always_inline void |
124 | callthunks_patch_module_calls(struct callthunk_sites *sites, | |
125 | struct module *mod) {} | |
7825451f PZ |
126 | static __always_inline void *callthunks_translate_call_dest(void *dest) |
127 | { | |
128 | return dest; | |
129 | } | |
b2e9dfe5 TG |
130 | static __always_inline int x86_call_depth_emit_accounting(u8 **pprog, |
131 | void *func) | |
132 | { | |
133 | return 0; | |
134 | } | |
e81dc127 | 135 | #endif |
6b592570 PA |
136 | |
137 | #ifdef CONFIG_SMP | |
138 | extern void alternatives_smp_module_add(struct module *mod, char *name, | |
139 | void *locks, void *locks_end, | |
140 | void *text, void *text_end); | |
141 | extern void alternatives_smp_module_del(struct module *mod); | |
816afe4f | 142 | extern void alternatives_enable_smp(void); |
2cfa1978 | 143 | extern int alternatives_text_reserved(void *start, void *end); |
3fb82d56 | 144 | extern bool skip_smp_alternatives; |
6b592570 PA |
145 | #else |
146 | static inline void alternatives_smp_module_add(struct module *mod, char *name, | |
2ac1ea7c JP |
147 | void *locks, void *locks_end, |
148 | void *text, void *text_end) {} | |
6b592570 | 149 | static inline void alternatives_smp_module_del(struct module *mod) {} |
816afe4f | 150 | static inline void alternatives_enable_smp(void) {} |
2cfa1978 MH |
151 | static inline int alternatives_text_reserved(void *start, void *end) |
152 | { | |
153 | return 0; | |
154 | } | |
6b592570 PA |
155 | #endif /* CONFIG_SMP */ |
156 | ||
da0fe6e6 JG |
157 | #define ALT_CALL_INSTR "call BUG_func" |
158 | ||
4332195c BP |
159 | #define b_replacement(num) "664"#num |
160 | #define e_replacement(num) "665"#num | |
954e482b | 161 | |
4332195c BP |
162 | #define alt_end_marker "663" |
163 | #define alt_slen "662b-661b" | |
4332195c BP |
164 | #define alt_total_slen alt_end_marker"b-661b" |
165 | #define alt_rlen(num) e_replacement(num)"f-"b_replacement(num)"f" | |
954e482b | 166 | |
1c1ed473 BP |
167 | #define OLDINSTR(oldinstr, num) \ |
168 | "# ALT: oldnstr\n" \ | |
4332195c | 169 | "661:\n\t" oldinstr "\n662:\n" \ |
1c1ed473 | 170 | "# ALT: padding\n" \ |
4332195c | 171 | ".skip -(((" alt_rlen(num) ")-(" alt_slen ")) > 0) * " \ |
1c1ed473 | 172 | "((" alt_rlen(num) ")-(" alt_slen ")),0x90\n" \ |
4332195c BP |
173 | alt_end_marker ":\n" |
174 | ||
dbe4058a | 175 | /* |
6b32c126 | 176 | * gas compatible max based on the idea from: |
dbe4058a BP |
177 | * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax |
178 | * | |
6b32c126 | 179 | * The additional "-" is needed because gas uses a "true" value of -1. |
dbe4058a | 180 | */ |
6b32c126 | 181 | #define alt_max_short(a, b) "((" a ") ^ (((" a ") ^ (" b ")) & -(-((" a ") < (" b ")))))" |
dbe4058a | 182 | |
4332195c BP |
183 | /* |
184 | * Pad the second replacement alternative with additional NOPs if it is | |
185 | * additionally longer than the first replacement alternative. | |
186 | */ | |
dbe4058a | 187 | #define OLDINSTR_2(oldinstr, num1, num2) \ |
1c1ed473 | 188 | "# ALT: oldinstr2\n" \ |
dbe4058a | 189 | "661:\n\t" oldinstr "\n662:\n" \ |
1c1ed473 | 190 | "# ALT: padding2\n" \ |
dbe4058a BP |
191 | ".skip -((" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")) > 0) * " \ |
192 | "(" alt_max_short(alt_rlen(num1), alt_rlen(num2)) " - (" alt_slen ")), 0x90\n" \ | |
4332195c BP |
193 | alt_end_marker ":\n" |
194 | ||
71a93c26 BP |
195 | #define OLDINSTR_3(oldinsn, n1, n2, n3) \ |
196 | "# ALT: oldinstr3\n" \ | |
197 | "661:\n\t" oldinsn "\n662:\n" \ | |
198 | "# ALT: padding3\n" \ | |
199 | ".skip -((" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \ | |
200 | " - (" alt_slen ")) > 0) * " \ | |
201 | "(" alt_max_short(alt_max_short(alt_rlen(n1), alt_rlen(n2)), alt_rlen(n3)) \ | |
202 | " - (" alt_slen ")), 0x90\n" \ | |
203 | alt_end_marker ":\n" | |
204 | ||
5d1dd961 | 205 | #define ALTINSTR_ENTRY(ft_flags, num) \ |
954e482b | 206 | " .long 661b - .\n" /* label */ \ |
4332195c | 207 | " .long " b_replacement(num)"f - .\n" /* new instruction */ \ |
5d1dd961 | 208 | " .4byte " __stringify(ft_flags) "\n" /* feature + flags */ \ |
4332195c | 209 | " .byte " alt_total_slen "\n" /* source len */ \ |
23c1ad53 | 210 | " .byte " alt_rlen(num) "\n" /* replacement len */ |
954e482b | 211 | |
db16e072 | 212 | #define ALTINSTR_REPLACEMENT(newinstr, num) /* replacement */ \ |
1c1ed473 BP |
213 | "# ALT: replacement " #num "\n" \ |
214 | b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n" | |
954e482b | 215 | |
edc953fa | 216 | /* alternative assembly primitive: */ |
5d1dd961 | 217 | #define ALTERNATIVE(oldinstr, newinstr, ft_flags) \ |
4332195c | 218 | OLDINSTR(oldinstr, 1) \ |
9cebed42 | 219 | ".pushsection .altinstructions,\"a\"\n" \ |
5d1dd961 | 220 | ALTINSTR_ENTRY(ft_flags, 1) \ |
9cebed42 | 221 | ".popsection\n" \ |
9cebed42 | 222 | ".pushsection .altinstr_replacement, \"ax\"\n" \ |
db16e072 | 223 | ALTINSTR_REPLACEMENT(newinstr, 1) \ |
b9e705ef | 224 | ".popsection\n" |
954e482b | 225 | |
5d1dd961 | 226 | #define ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \ |
4332195c | 227 | OLDINSTR_2(oldinstr, 1, 2) \ |
9cebed42 | 228 | ".pushsection .altinstructions,\"a\"\n" \ |
5d1dd961 BPA |
229 | ALTINSTR_ENTRY(ft_flags1, 1) \ |
230 | ALTINSTR_ENTRY(ft_flags2, 2) \ | |
9cebed42 | 231 | ".popsection\n" \ |
9cebed42 | 232 | ".pushsection .altinstr_replacement, \"ax\"\n" \ |
db16e072 JG |
233 | ALTINSTR_REPLACEMENT(newinstr1, 1) \ |
234 | ALTINSTR_REPLACEMENT(newinstr2, 2) \ | |
b9e705ef | 235 | ".popsection\n" |
edc953fa | 236 | |
e208b3c4 | 237 | /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ |
5d1dd961 | 238 | #define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \ |
e208b3c4 | 239 | ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ |
5d1dd961 BPA |
240 | newinstr_yes, ft_flags) |
241 | ||
242 | #define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \ | |
243 | newinsn3, ft_flags3) \ | |
244 | OLDINSTR_3(oldinsn, 1, 2, 3) \ | |
245 | ".pushsection .altinstructions,\"a\"\n" \ | |
246 | ALTINSTR_ENTRY(ft_flags1, 1) \ | |
247 | ALTINSTR_ENTRY(ft_flags2, 2) \ | |
248 | ALTINSTR_ENTRY(ft_flags3, 3) \ | |
249 | ".popsection\n" \ | |
250 | ".pushsection .altinstr_replacement, \"ax\"\n" \ | |
251 | ALTINSTR_REPLACEMENT(newinsn1, 1) \ | |
252 | ALTINSTR_REPLACEMENT(newinsn2, 2) \ | |
253 | ALTINSTR_REPLACEMENT(newinsn3, 3) \ | |
71a93c26 BP |
254 | ".popsection\n" |
255 | ||
6b592570 PA |
256 | /* |
257 | * Alternative instructions for different CPU types or capabilities. | |
258 | * | |
259 | * This allows to use optimized instructions even on generic binary | |
260 | * kernels. | |
261 | * | |
262 | * length of oldinstr must be longer or equal the length of newinstr | |
263 | * It can be padded with nops as needed. | |
264 | * | |
265 | * For non barrier like inlines please define new variants | |
266 | * without volatile and memory clobber. | |
267 | */ | |
5d1dd961 BPA |
268 | #define alternative(oldinstr, newinstr, ft_flags) \ |
269 | asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory") | |
6b592570 | 270 | |
5d1dd961 BPA |
271 | #define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \ |
272 | asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory") | |
4332195c | 273 | |
5d1dd961 BPA |
274 | #define alternative_ternary(oldinstr, ft_flags, newinstr_yes, newinstr_no) \ |
275 | asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) ::: "memory") | |
e208b3c4 | 276 | |
6b592570 PA |
277 | /* |
278 | * Alternative inline assembly with input. | |
279 | * | |
a97673a1 | 280 | * Peculiarities: |
6b592570 PA |
281 | * No memory clobber here. |
282 | * Argument numbers start with 1. | |
edc953fa | 283 | * Leaving an unused argument 0 to keep API compatibility. |
6b592570 | 284 | */ |
5d1dd961 BPA |
285 | #define alternative_input(oldinstr, newinstr, ft_flags, input...) \ |
286 | asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) \ | |
edc953fa | 287 | : : "i" (0), ## input) |
6b592570 | 288 | |
5b3e83f4 FY |
289 | /* |
290 | * This is similar to alternative_input. But it has two features and | |
291 | * respective instructions. | |
292 | * | |
293 | * If CPU has feature2, newinstr2 is used. | |
294 | * Otherwise, if CPU has feature1, newinstr1 is used. | |
295 | * Otherwise, oldinstr is used. | |
296 | */ | |
5d1dd961 BPA |
297 | #define alternative_input_2(oldinstr, newinstr1, ft_flags1, newinstr2, \ |
298 | ft_flags2, input...) \ | |
299 | asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, \ | |
300 | newinstr2, ft_flags2) \ | |
5b3e83f4 FY |
301 | : : "i" (0), ## input) |
302 | ||
6b592570 | 303 | /* Like alternative_input, but with a single output argument */ |
5d1dd961 BPA |
304 | #define alternative_io(oldinstr, newinstr, ft_flags, output, input...) \ |
305 | asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) \ | |
edc953fa | 306 | : output : "i" (0), ## input) |
6b592570 | 307 | |
1b1d9258 | 308 | /* Like alternative_io, but for replacing a direct call with another one. */ |
5d1dd961 BPA |
309 | #define alternative_call(oldfunc, newfunc, ft_flags, output, input...) \ |
310 | asm_inline volatile (ALTERNATIVE("call %P[old]", "call %P[new]", ft_flags) \ | |
1b1d9258 JB |
311 | : output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input) |
312 | ||
954e482b FY |
313 | /* |
314 | * Like alternative_call, but there are two features and respective functions. | |
315 | * If CPU has feature2, function2 is used. | |
316 | * Otherwise, if CPU has feature1, function1 is used. | |
317 | * Otherwise, old function is used. | |
318 | */ | |
5d1dd961 | 319 | #define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2, \ |
954e482b | 320 | output, input...) \ |
5d1dd961 BPA |
321 | asm_inline volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", ft_flags1,\ |
322 | "call %P[new2]", ft_flags2) \ | |
f5caf621 | 323 | : output, ASM_CALL_CONSTRAINT \ |
317c2ce7 | 324 | : [old] "i" (oldfunc), [new1] "i" (newfunc1), \ |
bd627103 | 325 | [new2] "i" (newfunc2), ## input) |
954e482b | 326 | |
6b592570 PA |
327 | /* |
328 | * use this macro(s) if you need more than one output parameter | |
329 | * in alternative_io | |
330 | */ | |
1b1d9258 | 331 | #define ASM_OUTPUT2(a...) a |
6b592570 | 332 | |
819165fb JB |
333 | /* |
334 | * use this macro if you need clobbers but no inputs in | |
335 | * alternative_{input,io,call}() | |
336 | */ | |
337 | #define ASM_NO_INPUT_CLOBBER(clbr...) "i" (0) : clbr | |
338 | ||
9824b00c JG |
339 | /* Macro for creating assembler functions avoiding any C magic. */ |
340 | #define DEFINE_ASM_FUNC(func, instr, sec) \ | |
341 | asm (".pushsection " #sec ", \"ax\"\n" \ | |
342 | ".global " #func "\n\t" \ | |
343 | ".type " #func ", @function\n\t" \ | |
344 | ASM_FUNC_ALIGN "\n" \ | |
345 | #func ":\n\t" \ | |
346 | ASM_ENDBR \ | |
347 | instr "\n\t" \ | |
348 | ASM_RET \ | |
349 | ".size " #func ", . - " #func "\n\t" \ | |
350 | ".popsection") | |
351 | ||
352 | void BUG_func(void); | |
353 | void nop_func(void); | |
354 | ||
5e21a3ec JG |
355 | #else /* __ASSEMBLY__ */ |
356 | ||
357 | #ifdef CONFIG_SMP | |
358 | .macro LOCK_PREFIX | |
359 | 672: lock | |
360 | .pushsection .smp_locks,"a" | |
361 | .balign 4 | |
362 | .long 672b - . | |
363 | .popsection | |
364 | .endm | |
365 | #else | |
366 | .macro LOCK_PREFIX | |
367 | .endm | |
368 | #endif | |
369 | ||
370 | /* | |
371 | * objtool annotation to ignore the alternatives and only consider the original | |
372 | * instruction(s). | |
373 | */ | |
374 | .macro ANNOTATE_IGNORE_ALTERNATIVE | |
375 | .Lannotate_\@: | |
376 | .pushsection .discard.ignore_alts | |
b8ec60e1 | 377 | .long .Lannotate_\@ |
5e21a3ec JG |
378 | .popsection |
379 | .endm | |
380 | ||
381 | /* | |
382 | * Issue one struct alt_instr descriptor entry (need to put it into | |
383 | * the section .altinstructions, see below). This entry contains | |
384 | * enough information for the alternatives patching code to patch an | |
385 | * instruction. See apply_alternatives(). | |
386 | */ | |
5d1dd961 | 387 | .macro altinstr_entry orig alt ft_flags orig_len alt_len |
5e21a3ec JG |
388 | .long \orig - . |
389 | .long \alt - . | |
5d1dd961 | 390 | .4byte \ft_flags |
5e21a3ec JG |
391 | .byte \orig_len |
392 | .byte \alt_len | |
5e21a3ec JG |
393 | .endm |
394 | ||
da0fe6e6 JG |
395 | .macro ALT_CALL_INSTR |
396 | call BUG_func | |
397 | .endm | |
398 | ||
5e21a3ec JG |
399 | /* |
400 | * Define an alternative between two instructions. If @feature is | |
401 | * present, early code in apply_alternatives() replaces @oldinstr with | |
402 | * @newinstr. ".skip" directive takes care of proper instruction padding | |
403 | * in case @newinstr is longer than @oldinstr. | |
404 | */ | |
5d1dd961 | 405 | .macro ALTERNATIVE oldinstr, newinstr, ft_flags |
5e21a3ec JG |
406 | 140: |
407 | \oldinstr | |
408 | 141: | |
409 | .skip -(((144f-143f)-(141b-140b)) > 0) * ((144f-143f)-(141b-140b)),0x90 | |
410 | 142: | |
411 | ||
412 | .pushsection .altinstructions,"a" | |
5d1dd961 | 413 | altinstr_entry 140b,143f,\ft_flags,142b-140b,144f-143f |
5e21a3ec JG |
414 | .popsection |
415 | ||
416 | .pushsection .altinstr_replacement,"ax" | |
417 | 143: | |
418 | \newinstr | |
419 | 144: | |
420 | .popsection | |
421 | .endm | |
422 | ||
423 | #define old_len 141b-140b | |
424 | #define new_len1 144f-143f | |
425 | #define new_len2 145f-144f | |
52354973 | 426 | #define new_len3 146f-145f |
5e21a3ec JG |
427 | |
428 | /* | |
429 | * gas compatible max based on the idea from: | |
430 | * http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax | |
431 | * | |
432 | * The additional "-" is needed because gas uses a "true" value of -1. | |
433 | */ | |
52354973 PZ |
434 | #define alt_max_2(a, b) ((a) ^ (((a) ^ (b)) & -(-((a) < (b))))) |
435 | #define alt_max_3(a, b, c) (alt_max_2(alt_max_2(a, b), c)) | |
5e21a3ec JG |
436 | |
437 | ||
438 | /* | |
439 | * Same as ALTERNATIVE macro above but for two alternatives. If CPU | |
440 | * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has | |
441 | * @feature2, it replaces @oldinstr with @feature2. | |
442 | */ | |
5d1dd961 | 443 | .macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2 |
5e21a3ec JG |
444 | 140: |
445 | \oldinstr | |
446 | 141: | |
52354973 PZ |
447 | .skip -((alt_max_2(new_len1, new_len2) - (old_len)) > 0) * \ |
448 | (alt_max_2(new_len1, new_len2) - (old_len)),0x90 | |
5e21a3ec JG |
449 | 142: |
450 | ||
451 | .pushsection .altinstructions,"a" | |
5d1dd961 BPA |
452 | altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f |
453 | altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f | |
5e21a3ec JG |
454 | .popsection |
455 | ||
456 | .pushsection .altinstr_replacement,"ax" | |
457 | 143: | |
458 | \newinstr1 | |
459 | 144: | |
460 | \newinstr2 | |
461 | 145: | |
462 | .popsection | |
463 | .endm | |
464 | ||
5d1dd961 | 465 | .macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3 |
52354973 PZ |
466 | 140: |
467 | \oldinstr | |
468 | 141: | |
469 | .skip -((alt_max_3(new_len1, new_len2, new_len3) - (old_len)) > 0) * \ | |
470 | (alt_max_3(new_len1, new_len2, new_len3) - (old_len)),0x90 | |
471 | 142: | |
472 | ||
473 | .pushsection .altinstructions,"a" | |
5d1dd961 BPA |
474 | altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f |
475 | altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f | |
476 | altinstr_entry 140b,145f,\ft_flags3,142b-140b,146f-145f | |
52354973 PZ |
477 | .popsection |
478 | ||
479 | .pushsection .altinstr_replacement,"ax" | |
480 | 143: | |
481 | \newinstr1 | |
482 | 144: | |
483 | \newinstr2 | |
484 | 145: | |
485 | \newinstr3 | |
486 | 146: | |
487 | .popsection | |
488 | .endm | |
489 | ||
e208b3c4 | 490 | /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */ |
5d1dd961 | 491 | #define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \ |
e208b3c4 | 492 | ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS, \ |
5d1dd961 | 493 | newinstr_yes, ft_flags |
e208b3c4 | 494 | |
f005f5d8 AL |
495 | #endif /* __ASSEMBLY__ */ |
496 | ||
1965aae3 | 497 | #endif /* _ASM_X86_ALTERNATIVE_H */ |