Commit | Line | Data |
---|---|---|
c767a54b JP |
1 | #define pr_fmt(fmt) "SMP alternatives: " fmt |
2 | ||
9a0b5817 | 3 | #include <linux/module.h> |
f6a57033 | 4 | #include <linux/sched.h> |
2f1dafe5 | 5 | #include <linux/mutex.h> |
9a0b5817 | 6 | #include <linux/list.h> |
8b5a10fc | 7 | #include <linux/stringify.h> |
19d36ccd AK |
8 | #include <linux/mm.h> |
9 | #include <linux/vmalloc.h> | |
3945dab4 | 10 | #include <linux/memory.h> |
3d55cc8a | 11 | #include <linux/stop_machine.h> |
5a0e3ad6 | 12 | #include <linux/slab.h> |
fd4363ff | 13 | #include <linux/kdebug.h> |
9a0b5817 GH |
14 | #include <asm/alternative.h> |
15 | #include <asm/sections.h> | |
19d36ccd | 16 | #include <asm/pgtable.h> |
8f4e956b AK |
17 | #include <asm/mce.h> |
18 | #include <asm/nmi.h> | |
e587cadd | 19 | #include <asm/cacheflush.h> |
78ff7fae | 20 | #include <asm/tlbflush.h> |
e587cadd | 21 | #include <asm/io.h> |
78ff7fae | 22 | #include <asm/fixmap.h> |
9a0b5817 | 23 | |
ab144f5e AK |
24 | #define MAX_PATCH_LEN (255-1) |
25 | ||
8b5a10fc | 26 | static int __initdata_or_module debug_alternative; |
b7fb4af0 | 27 | |
d167a518 GH |
28 | static int __init debug_alt(char *str) |
29 | { | |
30 | debug_alternative = 1; | |
31 | return 1; | |
32 | } | |
d167a518 GH |
33 | __setup("debug-alternative", debug_alt); |
34 | ||
09488165 JB |
35 | static int noreplace_smp; |
36 | ||
b7fb4af0 JF |
37 | static int __init setup_noreplace_smp(char *str) |
38 | { | |
39 | noreplace_smp = 1; | |
40 | return 1; | |
41 | } | |
42 | __setup("noreplace-smp", setup_noreplace_smp); | |
43 | ||
959b4fdf | 44 | #ifdef CONFIG_PARAVIRT |
8b5a10fc | 45 | static int __initdata_or_module noreplace_paravirt = 0; |
959b4fdf JF |
46 | |
47 | static int __init setup_noreplace_paravirt(char *str) | |
48 | { | |
49 | noreplace_paravirt = 1; | |
50 | return 1; | |
51 | } | |
52 | __setup("noreplace-paravirt", setup_noreplace_paravirt); | |
53 | #endif | |
b7fb4af0 | 54 | |
db477a33 BP |
55 | #define DPRINTK(fmt, args...) \ |
56 | do { \ | |
57 | if (debug_alternative) \ | |
58 | printk(KERN_DEBUG "%s: " fmt "\n", __func__, ##args); \ | |
c767a54b | 59 | } while (0) |
d167a518 | 60 | |
48c7a250 BP |
61 | #define DUMP_BYTES(buf, len, fmt, args...) \ |
62 | do { \ | |
63 | if (unlikely(debug_alternative)) { \ | |
64 | int j; \ | |
65 | \ | |
66 | if (!(len)) \ | |
67 | break; \ | |
68 | \ | |
69 | printk(KERN_DEBUG fmt, ##args); \ | |
70 | for (j = 0; j < (len) - 1; j++) \ | |
71 | printk(KERN_CONT "%02hhx ", buf[j]); \ | |
72 | printk(KERN_CONT "%02hhx\n", buf[j]); \ | |
73 | } \ | |
74 | } while (0) | |
75 | ||
dc326fca PA |
76 | /* |
77 | * Each GENERIC_NOPX is of X bytes, and defined as an array of bytes | |
78 | * that correspond to that nop. Getting from one nop to the next, we | |
79 | * add to the array the offset that is equal to the sum of all sizes of | |
80 | * nops preceding the one we are after. | |
81 | * | |
82 | * Note: The GENERIC_NOP5_ATOMIC is at the end, as it breaks the | |
83 | * nice symmetry of sizes of the previous nops. | |
84 | */ | |
8b5a10fc | 85 | #if defined(GENERIC_NOP1) && !defined(CONFIG_X86_64) |
dc326fca PA |
86 | static const unsigned char intelnops[] = |
87 | { | |
88 | GENERIC_NOP1, | |
89 | GENERIC_NOP2, | |
90 | GENERIC_NOP3, | |
91 | GENERIC_NOP4, | |
92 | GENERIC_NOP5, | |
93 | GENERIC_NOP6, | |
94 | GENERIC_NOP7, | |
95 | GENERIC_NOP8, | |
96 | GENERIC_NOP5_ATOMIC | |
97 | }; | |
98 | static const unsigned char * const intel_nops[ASM_NOP_MAX+2] = | |
99 | { | |
9a0b5817 GH |
100 | NULL, |
101 | intelnops, | |
102 | intelnops + 1, | |
103 | intelnops + 1 + 2, | |
104 | intelnops + 1 + 2 + 3, | |
105 | intelnops + 1 + 2 + 3 + 4, | |
106 | intelnops + 1 + 2 + 3 + 4 + 5, | |
107 | intelnops + 1 + 2 + 3 + 4 + 5 + 6, | |
108 | intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
dc326fca | 109 | intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8, |
9a0b5817 | 110 | }; |
d167a518 GH |
111 | #endif |
112 | ||
113 | #ifdef K8_NOP1 | |
dc326fca PA |
114 | static const unsigned char k8nops[] = |
115 | { | |
116 | K8_NOP1, | |
117 | K8_NOP2, | |
118 | K8_NOP3, | |
119 | K8_NOP4, | |
120 | K8_NOP5, | |
121 | K8_NOP6, | |
122 | K8_NOP7, | |
123 | K8_NOP8, | |
124 | K8_NOP5_ATOMIC | |
125 | }; | |
126 | static const unsigned char * const k8_nops[ASM_NOP_MAX+2] = | |
127 | { | |
9a0b5817 GH |
128 | NULL, |
129 | k8nops, | |
130 | k8nops + 1, | |
131 | k8nops + 1 + 2, | |
132 | k8nops + 1 + 2 + 3, | |
133 | k8nops + 1 + 2 + 3 + 4, | |
134 | k8nops + 1 + 2 + 3 + 4 + 5, | |
135 | k8nops + 1 + 2 + 3 + 4 + 5 + 6, | |
136 | k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
dc326fca | 137 | k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8, |
9a0b5817 | 138 | }; |
d167a518 GH |
139 | #endif |
140 | ||
8b5a10fc | 141 | #if defined(K7_NOP1) && !defined(CONFIG_X86_64) |
dc326fca PA |
142 | static const unsigned char k7nops[] = |
143 | { | |
144 | K7_NOP1, | |
145 | K7_NOP2, | |
146 | K7_NOP3, | |
147 | K7_NOP4, | |
148 | K7_NOP5, | |
149 | K7_NOP6, | |
150 | K7_NOP7, | |
151 | K7_NOP8, | |
152 | K7_NOP5_ATOMIC | |
153 | }; | |
154 | static const unsigned char * const k7_nops[ASM_NOP_MAX+2] = | |
155 | { | |
9a0b5817 GH |
156 | NULL, |
157 | k7nops, | |
158 | k7nops + 1, | |
159 | k7nops + 1 + 2, | |
160 | k7nops + 1 + 2 + 3, | |
161 | k7nops + 1 + 2 + 3 + 4, | |
162 | k7nops + 1 + 2 + 3 + 4 + 5, | |
163 | k7nops + 1 + 2 + 3 + 4 + 5 + 6, | |
164 | k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
dc326fca | 165 | k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8, |
9a0b5817 | 166 | }; |
d167a518 GH |
167 | #endif |
168 | ||
32c464f5 | 169 | #ifdef P6_NOP1 |
cb09cad4 | 170 | static const unsigned char p6nops[] = |
dc326fca PA |
171 | { |
172 | P6_NOP1, | |
173 | P6_NOP2, | |
174 | P6_NOP3, | |
175 | P6_NOP4, | |
176 | P6_NOP5, | |
177 | P6_NOP6, | |
178 | P6_NOP7, | |
179 | P6_NOP8, | |
180 | P6_NOP5_ATOMIC | |
181 | }; | |
182 | static const unsigned char * const p6_nops[ASM_NOP_MAX+2] = | |
183 | { | |
32c464f5 JB |
184 | NULL, |
185 | p6nops, | |
186 | p6nops + 1, | |
187 | p6nops + 1 + 2, | |
188 | p6nops + 1 + 2 + 3, | |
189 | p6nops + 1 + 2 + 3 + 4, | |
190 | p6nops + 1 + 2 + 3 + 4 + 5, | |
191 | p6nops + 1 + 2 + 3 + 4 + 5 + 6, | |
192 | p6nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
dc326fca | 193 | p6nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8, |
32c464f5 JB |
194 | }; |
195 | #endif | |
196 | ||
dc326fca | 197 | /* Initialize these to a safe default */ |
d167a518 | 198 | #ifdef CONFIG_X86_64 |
dc326fca PA |
199 | const unsigned char * const *ideal_nops = p6_nops; |
200 | #else | |
201 | const unsigned char * const *ideal_nops = intel_nops; | |
202 | #endif | |
d167a518 | 203 | |
dc326fca | 204 | void __init arch_init_ideal_nops(void) |
d167a518 | 205 | { |
dc326fca PA |
206 | switch (boot_cpu_data.x86_vendor) { |
207 | case X86_VENDOR_INTEL: | |
d8d9766c PA |
208 | /* |
209 | * Due to a decoder implementation quirk, some | |
210 | * specific Intel CPUs actually perform better with | |
211 | * the "k8_nops" than with the SDM-recommended NOPs. | |
212 | */ | |
213 | if (boot_cpu_data.x86 == 6 && | |
214 | boot_cpu_data.x86_model >= 0x0f && | |
215 | boot_cpu_data.x86_model != 0x1c && | |
216 | boot_cpu_data.x86_model != 0x26 && | |
217 | boot_cpu_data.x86_model != 0x27 && | |
218 | boot_cpu_data.x86_model < 0x30) { | |
219 | ideal_nops = k8_nops; | |
220 | } else if (boot_cpu_has(X86_FEATURE_NOPL)) { | |
dc326fca PA |
221 | ideal_nops = p6_nops; |
222 | } else { | |
223 | #ifdef CONFIG_X86_64 | |
224 | ideal_nops = k8_nops; | |
225 | #else | |
226 | ideal_nops = intel_nops; | |
227 | #endif | |
228 | } | |
d6250a3f | 229 | break; |
dc326fca PA |
230 | default: |
231 | #ifdef CONFIG_X86_64 | |
232 | ideal_nops = k8_nops; | |
233 | #else | |
234 | if (boot_cpu_has(X86_FEATURE_K8)) | |
235 | ideal_nops = k8_nops; | |
236 | else if (boot_cpu_has(X86_FEATURE_K7)) | |
237 | ideal_nops = k7_nops; | |
238 | else | |
239 | ideal_nops = intel_nops; | |
240 | #endif | |
241 | } | |
9a0b5817 GH |
242 | } |
243 | ||
ab144f5e | 244 | /* Use this to add nops to a buffer, then text_poke the whole buffer. */ |
8b5a10fc | 245 | static void __init_or_module add_nops(void *insns, unsigned int len) |
139ec7c4 | 246 | { |
139ec7c4 RR |
247 | while (len > 0) { |
248 | unsigned int noplen = len; | |
249 | if (noplen > ASM_NOP_MAX) | |
250 | noplen = ASM_NOP_MAX; | |
dc326fca | 251 | memcpy(insns, ideal_nops[noplen], noplen); |
139ec7c4 RR |
252 | insns += noplen; |
253 | len -= noplen; | |
254 | } | |
255 | } | |
256 | ||
d167a518 | 257 | extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; |
5967ed87 | 258 | extern s32 __smp_locks[], __smp_locks_end[]; |
fa6f2cc7 | 259 | void *text_poke_early(void *addr, const void *opcode, size_t len); |
d167a518 | 260 | |
48c7a250 BP |
261 | /* |
262 | * Are we looking at a near JMP with a 1 or 4-byte displacement. | |
263 | */ | |
264 | static inline bool is_jmp(const u8 opcode) | |
265 | { | |
266 | return opcode == 0xeb || opcode == 0xe9; | |
267 | } | |
268 | ||
269 | static void __init_or_module | |
270 | recompute_jump(struct alt_instr *a, u8 *orig_insn, u8 *repl_insn, u8 *insnbuf) | |
271 | { | |
272 | u8 *next_rip, *tgt_rip; | |
273 | s32 n_dspl, o_dspl; | |
274 | int repl_len; | |
275 | ||
276 | if (a->replacementlen != 5) | |
277 | return; | |
278 | ||
279 | o_dspl = *(s32 *)(insnbuf + 1); | |
280 | ||
281 | /* next_rip of the replacement JMP */ | |
282 | next_rip = repl_insn + a->replacementlen; | |
283 | /* target rip of the replacement JMP */ | |
284 | tgt_rip = next_rip + o_dspl; | |
285 | n_dspl = tgt_rip - orig_insn; | |
286 | ||
287 | DPRINTK("target RIP: %p, new_displ: 0x%x", tgt_rip, n_dspl); | |
288 | ||
289 | if (tgt_rip - orig_insn >= 0) { | |
290 | if (n_dspl - 2 <= 127) | |
291 | goto two_byte_jmp; | |
292 | else | |
293 | goto five_byte_jmp; | |
294 | /* negative offset */ | |
295 | } else { | |
296 | if (((n_dspl - 2) & 0xff) == (n_dspl - 2)) | |
297 | goto two_byte_jmp; | |
298 | else | |
299 | goto five_byte_jmp; | |
300 | } | |
301 | ||
302 | two_byte_jmp: | |
303 | n_dspl -= 2; | |
304 | ||
305 | insnbuf[0] = 0xeb; | |
306 | insnbuf[1] = (s8)n_dspl; | |
307 | add_nops(insnbuf + 2, 3); | |
308 | ||
309 | repl_len = 2; | |
310 | goto done; | |
311 | ||
312 | five_byte_jmp: | |
313 | n_dspl -= 5; | |
314 | ||
315 | insnbuf[0] = 0xe9; | |
316 | *(s32 *)&insnbuf[1] = n_dspl; | |
317 | ||
318 | repl_len = 5; | |
319 | ||
320 | done: | |
321 | ||
322 | DPRINTK("final displ: 0x%08x, JMP 0x%lx", | |
323 | n_dspl, (unsigned long)orig_insn + n_dspl + repl_len); | |
324 | } | |
325 | ||
db477a33 BP |
326 | /* |
327 | * Replace instructions with better alternatives for this CPU type. This runs | |
328 | * before SMP is initialized to avoid SMP problems with self modifying code. | |
329 | * This implies that asymmetric systems where APs have less capabilities than | |
330 | * the boot processor are not handled. Tough. Make sure you disable such | |
331 | * features by hand. | |
332 | */ | |
8b5a10fc JB |
333 | void __init_or_module apply_alternatives(struct alt_instr *start, |
334 | struct alt_instr *end) | |
9a0b5817 | 335 | { |
9a0b5817 | 336 | struct alt_instr *a; |
59e97e4d | 337 | u8 *instr, *replacement; |
1b1d9258 | 338 | u8 insnbuf[MAX_PATCH_LEN]; |
9a0b5817 | 339 | |
db477a33 | 340 | DPRINTK("alt table %p -> %p", start, end); |
50973133 FY |
341 | /* |
342 | * The scan order should be from start to end. A later scanned | |
db477a33 | 343 | * alternative code can overwrite previously scanned alternative code. |
50973133 FY |
344 | * Some kernel functions (e.g. memcpy, memset, etc) use this order to |
345 | * patch code. | |
346 | * | |
347 | * So be careful if you want to change the scan order to any other | |
348 | * order. | |
349 | */ | |
9a0b5817 | 350 | for (a = start; a < end; a++) { |
48c7a250 BP |
351 | int insnbuf_sz = 0; |
352 | ||
59e97e4d AL |
353 | instr = (u8 *)&a->instr_offset + a->instr_offset; |
354 | replacement = (u8 *)&a->repl_offset + a->repl_offset; | |
ab144f5e | 355 | BUG_ON(a->instrlen > sizeof(insnbuf)); |
65fc985b | 356 | BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32); |
9a0b5817 GH |
357 | if (!boot_cpu_has(a->cpuid)) |
358 | continue; | |
59e97e4d | 359 | |
db477a33 BP |
360 | DPRINTK("feat: %d*32+%d, old: (%p, len: %d), repl: (%p, len: %d)", |
361 | a->cpuid >> 5, | |
362 | a->cpuid & 0x1f, | |
363 | instr, a->instrlen, | |
364 | replacement, a->replacementlen); | |
365 | ||
48c7a250 BP |
366 | DUMP_BYTES(instr, a->instrlen, "%p: old_insn: ", instr); |
367 | DUMP_BYTES(replacement, a->replacementlen, "%p: rpl_insn: ", replacement); | |
368 | ||
59e97e4d | 369 | memcpy(insnbuf, replacement, a->replacementlen); |
48c7a250 | 370 | insnbuf_sz = a->replacementlen; |
59e97e4d AL |
371 | |
372 | /* 0xe8 is a relative jump; fix the offset. */ | |
db477a33 BP |
373 | if (*insnbuf == 0xe8 && a->replacementlen == 5) { |
374 | *(s32 *)(insnbuf + 1) += replacement - instr; | |
48c7a250 BP |
375 | DPRINTK("Fix CALL offset: 0x%x, CALL 0x%lx", |
376 | *(s32 *)(insnbuf + 1), | |
377 | (unsigned long)instr + *(s32 *)(insnbuf + 1) + 5); | |
db477a33 | 378 | } |
59e97e4d | 379 | |
48c7a250 BP |
380 | if (a->replacementlen && is_jmp(replacement[0])) |
381 | recompute_jump(a, instr, replacement, insnbuf); | |
382 | ||
383 | if (a->instrlen > a->replacementlen) { | |
4332195c BP |
384 | add_nops(insnbuf + a->replacementlen, |
385 | a->instrlen - a->replacementlen); | |
48c7a250 BP |
386 | insnbuf_sz += a->instrlen - a->replacementlen; |
387 | } | |
388 | DUMP_BYTES(insnbuf, insnbuf_sz, "%p: final_insn: ", instr); | |
59e97e4d | 389 | |
48c7a250 | 390 | text_poke_early(instr, insnbuf, insnbuf_sz); |
9a0b5817 GH |
391 | } |
392 | } | |
393 | ||
8ec4d41f | 394 | #ifdef CONFIG_SMP |
5967ed87 JB |
395 | static void alternatives_smp_lock(const s32 *start, const s32 *end, |
396 | u8 *text, u8 *text_end) | |
9a0b5817 | 397 | { |
5967ed87 | 398 | const s32 *poff; |
9a0b5817 | 399 | |
3945dab4 | 400 | mutex_lock(&text_mutex); |
5967ed87 JB |
401 | for (poff = start; poff < end; poff++) { |
402 | u8 *ptr = (u8 *)poff + *poff; | |
403 | ||
404 | if (!*poff || ptr < text || ptr >= text_end) | |
9a0b5817 | 405 | continue; |
f88f07e0 | 406 | /* turn DS segment override prefix into lock prefix */ |
d9c5841e PA |
407 | if (*ptr == 0x3e) |
408 | text_poke(ptr, ((unsigned char []){0xf0}), 1); | |
4b8073e4 | 409 | } |
3945dab4 | 410 | mutex_unlock(&text_mutex); |
9a0b5817 GH |
411 | } |
412 | ||
5967ed87 JB |
413 | static void alternatives_smp_unlock(const s32 *start, const s32 *end, |
414 | u8 *text, u8 *text_end) | |
9a0b5817 | 415 | { |
5967ed87 | 416 | const s32 *poff; |
9a0b5817 | 417 | |
3945dab4 | 418 | mutex_lock(&text_mutex); |
5967ed87 JB |
419 | for (poff = start; poff < end; poff++) { |
420 | u8 *ptr = (u8 *)poff + *poff; | |
421 | ||
422 | if (!*poff || ptr < text || ptr >= text_end) | |
9a0b5817 | 423 | continue; |
f88f07e0 | 424 | /* turn lock prefix into DS segment override prefix */ |
d9c5841e PA |
425 | if (*ptr == 0xf0) |
426 | text_poke(ptr, ((unsigned char []){0x3E}), 1); | |
4b8073e4 | 427 | } |
3945dab4 | 428 | mutex_unlock(&text_mutex); |
9a0b5817 GH |
429 | } |
430 | ||
431 | struct smp_alt_module { | |
432 | /* what is this ??? */ | |
433 | struct module *mod; | |
434 | char *name; | |
435 | ||
436 | /* ptrs to lock prefixes */ | |
5967ed87 JB |
437 | const s32 *locks; |
438 | const s32 *locks_end; | |
9a0b5817 GH |
439 | |
440 | /* .text segment, needed to avoid patching init code ;) */ | |
441 | u8 *text; | |
442 | u8 *text_end; | |
443 | ||
444 | struct list_head next; | |
445 | }; | |
446 | static LIST_HEAD(smp_alt_modules); | |
2f1dafe5 | 447 | static DEFINE_MUTEX(smp_alt); |
816afe4f | 448 | static bool uniproc_patched = false; /* protected by smp_alt */ |
9a0b5817 | 449 | |
8b5a10fc JB |
450 | void __init_or_module alternatives_smp_module_add(struct module *mod, |
451 | char *name, | |
452 | void *locks, void *locks_end, | |
453 | void *text, void *text_end) | |
9a0b5817 GH |
454 | { |
455 | struct smp_alt_module *smp; | |
9a0b5817 | 456 | |
816afe4f RR |
457 | mutex_lock(&smp_alt); |
458 | if (!uniproc_patched) | |
459 | goto unlock; | |
b7fb4af0 | 460 | |
816afe4f RR |
461 | if (num_possible_cpus() == 1) |
462 | /* Don't bother remembering, we'll never have to undo it. */ | |
463 | goto smp_unlock; | |
9a0b5817 GH |
464 | |
465 | smp = kzalloc(sizeof(*smp), GFP_KERNEL); | |
466 | if (NULL == smp) | |
816afe4f RR |
467 | /* we'll run the (safe but slow) SMP code then ... */ |
468 | goto unlock; | |
9a0b5817 GH |
469 | |
470 | smp->mod = mod; | |
471 | smp->name = name; | |
472 | smp->locks = locks; | |
473 | smp->locks_end = locks_end; | |
474 | smp->text = text; | |
475 | smp->text_end = text_end; | |
db477a33 BP |
476 | DPRINTK("locks %p -> %p, text %p -> %p, name %s\n", |
477 | smp->locks, smp->locks_end, | |
9a0b5817 GH |
478 | smp->text, smp->text_end, smp->name); |
479 | ||
9a0b5817 | 480 | list_add_tail(&smp->next, &smp_alt_modules); |
816afe4f RR |
481 | smp_unlock: |
482 | alternatives_smp_unlock(locks, locks_end, text, text_end); | |
483 | unlock: | |
2f1dafe5 | 484 | mutex_unlock(&smp_alt); |
9a0b5817 GH |
485 | } |
486 | ||
8b5a10fc | 487 | void __init_or_module alternatives_smp_module_del(struct module *mod) |
9a0b5817 GH |
488 | { |
489 | struct smp_alt_module *item; | |
9a0b5817 | 490 | |
2f1dafe5 | 491 | mutex_lock(&smp_alt); |
9a0b5817 GH |
492 | list_for_each_entry(item, &smp_alt_modules, next) { |
493 | if (mod != item->mod) | |
494 | continue; | |
495 | list_del(&item->next); | |
9a0b5817 | 496 | kfree(item); |
816afe4f | 497 | break; |
9a0b5817 | 498 | } |
2f1dafe5 | 499 | mutex_unlock(&smp_alt); |
9a0b5817 GH |
500 | } |
501 | ||
816afe4f | 502 | void alternatives_enable_smp(void) |
9a0b5817 GH |
503 | { |
504 | struct smp_alt_module *mod; | |
9a0b5817 | 505 | |
816afe4f RR |
506 | /* Why bother if there are no other CPUs? */ |
507 | BUG_ON(num_possible_cpus() == 1); | |
9a0b5817 | 508 | |
2f1dafe5 | 509 | mutex_lock(&smp_alt); |
ca74a6f8 | 510 | |
816afe4f | 511 | if (uniproc_patched) { |
c767a54b | 512 | pr_info("switching to SMP code\n"); |
816afe4f | 513 | BUG_ON(num_online_cpus() != 1); |
53756d37 JF |
514 | clear_cpu_cap(&boot_cpu_data, X86_FEATURE_UP); |
515 | clear_cpu_cap(&cpu_data(0), X86_FEATURE_UP); | |
9a0b5817 GH |
516 | list_for_each_entry(mod, &smp_alt_modules, next) |
517 | alternatives_smp_lock(mod->locks, mod->locks_end, | |
518 | mod->text, mod->text_end); | |
816afe4f | 519 | uniproc_patched = false; |
9a0b5817 | 520 | } |
2f1dafe5 | 521 | mutex_unlock(&smp_alt); |
9a0b5817 GH |
522 | } |
523 | ||
2cfa1978 MH |
524 | /* Return 1 if the address range is reserved for smp-alternatives */ |
525 | int alternatives_text_reserved(void *start, void *end) | |
526 | { | |
527 | struct smp_alt_module *mod; | |
5967ed87 | 528 | const s32 *poff; |
076dc4a6 MH |
529 | u8 *text_start = start; |
530 | u8 *text_end = end; | |
2cfa1978 MH |
531 | |
532 | list_for_each_entry(mod, &smp_alt_modules, next) { | |
076dc4a6 | 533 | if (mod->text > text_end || mod->text_end < text_start) |
2cfa1978 | 534 | continue; |
5967ed87 JB |
535 | for (poff = mod->locks; poff < mod->locks_end; poff++) { |
536 | const u8 *ptr = (const u8 *)poff + *poff; | |
537 | ||
538 | if (text_start <= ptr && text_end > ptr) | |
2cfa1978 | 539 | return 1; |
5967ed87 | 540 | } |
2cfa1978 MH |
541 | } |
542 | ||
543 | return 0; | |
544 | } | |
48c7a250 | 545 | #endif /* CONFIG_SMP */ |
8ec4d41f | 546 | |
139ec7c4 | 547 | #ifdef CONFIG_PARAVIRT |
8b5a10fc JB |
548 | void __init_or_module apply_paravirt(struct paravirt_patch_site *start, |
549 | struct paravirt_patch_site *end) | |
139ec7c4 | 550 | { |
98de032b | 551 | struct paravirt_patch_site *p; |
ab144f5e | 552 | char insnbuf[MAX_PATCH_LEN]; |
139ec7c4 | 553 | |
959b4fdf JF |
554 | if (noreplace_paravirt) |
555 | return; | |
556 | ||
139ec7c4 RR |
557 | for (p = start; p < end; p++) { |
558 | unsigned int used; | |
559 | ||
ab144f5e | 560 | BUG_ON(p->len > MAX_PATCH_LEN); |
d34fda4a CW |
561 | /* prep the buffer with the original instructions */ |
562 | memcpy(insnbuf, p->instr, p->len); | |
93b1eab3 JF |
563 | used = pv_init_ops.patch(p->instrtype, p->clobbers, insnbuf, |
564 | (unsigned long)p->instr, p->len); | |
7f63c41c | 565 | |
63f70270 JF |
566 | BUG_ON(used > p->len); |
567 | ||
139ec7c4 | 568 | /* Pad the rest with nops */ |
ab144f5e | 569 | add_nops(insnbuf + used, p->len - used); |
e587cadd | 570 | text_poke_early(p->instr, insnbuf, p->len); |
139ec7c4 | 571 | } |
139ec7c4 | 572 | } |
98de032b | 573 | extern struct paravirt_patch_site __start_parainstructions[], |
139ec7c4 RR |
574 | __stop_parainstructions[]; |
575 | #endif /* CONFIG_PARAVIRT */ | |
576 | ||
9a0b5817 GH |
577 | void __init alternative_instructions(void) |
578 | { | |
8f4e956b AK |
579 | /* The patching is not fully atomic, so try to avoid local interruptions |
580 | that might execute the to be patched code. | |
581 | Other CPUs are not running. */ | |
582 | stop_nmi(); | |
123aa76e AK |
583 | |
584 | /* | |
585 | * Don't stop machine check exceptions while patching. | |
586 | * MCEs only happen when something got corrupted and in this | |
587 | * case we must do something about the corruption. | |
588 | * Ignoring it is worse than a unlikely patching race. | |
589 | * Also machine checks tend to be broadcast and if one CPU | |
590 | * goes into machine check the others follow quickly, so we don't | |
591 | * expect a machine check to cause undue problems during to code | |
592 | * patching. | |
593 | */ | |
8f4e956b | 594 | |
9a0b5817 GH |
595 | apply_alternatives(__alt_instructions, __alt_instructions_end); |
596 | ||
8ec4d41f | 597 | #ifdef CONFIG_SMP |
816afe4f RR |
598 | /* Patch to UP if other cpus not imminent. */ |
599 | if (!noreplace_smp && (num_present_cpus() == 1 || setup_max_cpus <= 1)) { | |
600 | uniproc_patched = true; | |
9a0b5817 GH |
601 | alternatives_smp_module_add(NULL, "core kernel", |
602 | __smp_locks, __smp_locks_end, | |
603 | _text, _etext); | |
9a0b5817 | 604 | } |
8f4e956b | 605 | |
816afe4f | 606 | if (!uniproc_patched || num_possible_cpus() == 1) |
f68fd5f4 FW |
607 | free_init_pages("SMP alternatives", |
608 | (unsigned long)__smp_locks, | |
609 | (unsigned long)__smp_locks_end); | |
816afe4f RR |
610 | #endif |
611 | ||
612 | apply_paravirt(__parainstructions, __parainstructions_end); | |
f68fd5f4 | 613 | |
8f4e956b | 614 | restart_nmi(); |
9a0b5817 | 615 | } |
19d36ccd | 616 | |
e587cadd MD |
617 | /** |
618 | * text_poke_early - Update instructions on a live kernel at boot time | |
619 | * @addr: address to modify | |
620 | * @opcode: source of the copy | |
621 | * @len: length to copy | |
622 | * | |
19d36ccd AK |
623 | * When you use this code to patch more than one byte of an instruction |
624 | * you need to make sure that other CPUs cannot execute this code in parallel. | |
e587cadd MD |
625 | * Also no thread must be currently preempted in the middle of these |
626 | * instructions. And on the local CPU you need to be protected again NMI or MCE | |
627 | * handlers seeing an inconsistent instruction while you patch. | |
19d36ccd | 628 | */ |
fa6f2cc7 | 629 | void *__init_or_module text_poke_early(void *addr, const void *opcode, |
8b5a10fc | 630 | size_t len) |
19d36ccd | 631 | { |
e587cadd MD |
632 | unsigned long flags; |
633 | local_irq_save(flags); | |
19d36ccd | 634 | memcpy(addr, opcode, len); |
e587cadd | 635 | sync_core(); |
5367b688 | 636 | local_irq_restore(flags); |
e587cadd MD |
637 | /* Could also do a CLFLUSH here to speed up CPU recovery; but |
638 | that causes hangs on some VIA CPUs. */ | |
639 | return addr; | |
640 | } | |
641 | ||
642 | /** | |
643 | * text_poke - Update instructions on a live kernel | |
644 | * @addr: address to modify | |
645 | * @opcode: source of the copy | |
646 | * @len: length to copy | |
647 | * | |
648 | * Only atomic text poke/set should be allowed when not doing early patching. | |
649 | * It means the size must be writable atomically and the address must be aligned | |
650 | * in a way that permits an atomic write. It also makes sure we fit on a single | |
651 | * page. | |
78ff7fae MH |
652 | * |
653 | * Note: Must be called under text_mutex. | |
e587cadd | 654 | */ |
9c54b616 | 655 | void *text_poke(void *addr, const void *opcode, size_t len) |
e587cadd | 656 | { |
78ff7fae | 657 | unsigned long flags; |
e587cadd | 658 | char *vaddr; |
b7b66baa MD |
659 | struct page *pages[2]; |
660 | int i; | |
e587cadd | 661 | |
b7b66baa MD |
662 | if (!core_kernel_text((unsigned long)addr)) { |
663 | pages[0] = vmalloc_to_page(addr); | |
664 | pages[1] = vmalloc_to_page(addr + PAGE_SIZE); | |
15a601eb | 665 | } else { |
b7b66baa | 666 | pages[0] = virt_to_page(addr); |
00c6b2d5 | 667 | WARN_ON(!PageReserved(pages[0])); |
b7b66baa | 668 | pages[1] = virt_to_page(addr + PAGE_SIZE); |
e587cadd | 669 | } |
b7b66baa | 670 | BUG_ON(!pages[0]); |
7cf49427 | 671 | local_irq_save(flags); |
78ff7fae MH |
672 | set_fixmap(FIX_TEXT_POKE0, page_to_phys(pages[0])); |
673 | if (pages[1]) | |
674 | set_fixmap(FIX_TEXT_POKE1, page_to_phys(pages[1])); | |
675 | vaddr = (char *)fix_to_virt(FIX_TEXT_POKE0); | |
b7b66baa | 676 | memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len); |
78ff7fae MH |
677 | clear_fixmap(FIX_TEXT_POKE0); |
678 | if (pages[1]) | |
679 | clear_fixmap(FIX_TEXT_POKE1); | |
680 | local_flush_tlb(); | |
19d36ccd | 681 | sync_core(); |
a534b679 AK |
682 | /* Could also do a CLFLUSH here to speed up CPU recovery; but |
683 | that causes hangs on some VIA CPUs. */ | |
b7b66baa MD |
684 | for (i = 0; i < len; i++) |
685 | BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]); | |
7cf49427 | 686 | local_irq_restore(flags); |
e587cadd | 687 | return addr; |
19d36ccd | 688 | } |
3d55cc8a | 689 | |
fd4363ff JK |
690 | static void do_sync_core(void *info) |
691 | { | |
692 | sync_core(); | |
693 | } | |
694 | ||
695 | static bool bp_patching_in_progress; | |
696 | static void *bp_int3_handler, *bp_int3_addr; | |
697 | ||
17f41571 | 698 | int poke_int3_handler(struct pt_regs *regs) |
fd4363ff | 699 | { |
fd4363ff JK |
700 | /* bp_patching_in_progress */ |
701 | smp_rmb(); | |
702 | ||
703 | if (likely(!bp_patching_in_progress)) | |
17f41571 | 704 | return 0; |
fd4363ff | 705 | |
17f41571 JK |
706 | if (user_mode_vm(regs) || regs->ip != (unsigned long)bp_int3_addr) |
707 | return 0; | |
fd4363ff JK |
708 | |
709 | /* set up the specified breakpoint handler */ | |
17f41571 JK |
710 | regs->ip = (unsigned long) bp_int3_handler; |
711 | ||
712 | return 1; | |
fd4363ff | 713 | |
fd4363ff | 714 | } |
17f41571 | 715 | |
fd4363ff JK |
716 | /** |
717 | * text_poke_bp() -- update instructions on live kernel on SMP | |
718 | * @addr: address to patch | |
719 | * @opcode: opcode of new instruction | |
720 | * @len: length to copy | |
721 | * @handler: address to jump to when the temporary breakpoint is hit | |
722 | * | |
723 | * Modify multi-byte instruction by using int3 breakpoint on SMP. | |
ea8596bb MH |
724 | * We completely avoid stop_machine() here, and achieve the |
725 | * synchronization using int3 breakpoint. | |
fd4363ff JK |
726 | * |
727 | * The way it is done: | |
728 | * - add a int3 trap to the address that will be patched | |
729 | * - sync cores | |
730 | * - update all but the first byte of the patched range | |
731 | * - sync cores | |
732 | * - replace the first byte (int3) by the first byte of | |
733 | * replacing opcode | |
734 | * - sync cores | |
735 | * | |
736 | * Note: must be called under text_mutex. | |
737 | */ | |
738 | void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler) | |
739 | { | |
740 | unsigned char int3 = 0xcc; | |
741 | ||
742 | bp_int3_handler = handler; | |
743 | bp_int3_addr = (u8 *)addr + sizeof(int3); | |
744 | bp_patching_in_progress = true; | |
745 | /* | |
746 | * Corresponding read barrier in int3 notifier for | |
747 | * making sure the in_progress flags is correctly ordered wrt. | |
748 | * patching | |
749 | */ | |
750 | smp_wmb(); | |
751 | ||
752 | text_poke(addr, &int3, sizeof(int3)); | |
753 | ||
754 | on_each_cpu(do_sync_core, NULL, 1); | |
755 | ||
756 | if (len - sizeof(int3) > 0) { | |
757 | /* patch all but the first byte */ | |
758 | text_poke((char *)addr + sizeof(int3), | |
759 | (const char *) opcode + sizeof(int3), | |
760 | len - sizeof(int3)); | |
761 | /* | |
762 | * According to Intel, this core syncing is very likely | |
763 | * not necessary and we'd be safe even without it. But | |
764 | * better safe than sorry (plus there's not only Intel). | |
765 | */ | |
766 | on_each_cpu(do_sync_core, NULL, 1); | |
767 | } | |
768 | ||
769 | /* patch the first byte */ | |
770 | text_poke(addr, opcode, sizeof(int3)); | |
771 | ||
772 | on_each_cpu(do_sync_core, NULL, 1); | |
773 | ||
774 | bp_patching_in_progress = false; | |
775 | smp_wmb(); | |
776 | ||
777 | return addr; | |
778 | } | |
779 |