Commit | Line | Data |
---|---|---|
9a0b5817 | 1 | #include <linux/module.h> |
f6a57033 | 2 | #include <linux/sched.h> |
2f1dafe5 | 3 | #include <linux/mutex.h> |
9a0b5817 | 4 | #include <linux/list.h> |
19d36ccd AK |
5 | #include <linux/kprobes.h> |
6 | #include <linux/mm.h> | |
7 | #include <linux/vmalloc.h> | |
9a0b5817 GH |
8 | #include <asm/alternative.h> |
9 | #include <asm/sections.h> | |
19d36ccd | 10 | #include <asm/pgtable.h> |
8f4e956b AK |
11 | #include <asm/mce.h> |
12 | #include <asm/nmi.h> | |
b097976e | 13 | #include <asm/vsyscall.h> |
e587cadd MD |
14 | #include <asm/cacheflush.h> |
15 | #include <asm/io.h> | |
9a0b5817 | 16 | |
ab144f5e AK |
17 | #define MAX_PATCH_LEN (255-1) |
18 | ||
09488165 JB |
19 | #ifdef CONFIG_HOTPLUG_CPU |
20 | static int smp_alt_once; | |
9a0b5817 | 21 | |
d167a518 GH |
22 | static int __init bootonly(char *str) |
23 | { | |
24 | smp_alt_once = 1; | |
25 | return 1; | |
26 | } | |
b7fb4af0 | 27 | __setup("smp-alt-boot", bootonly); |
09488165 JB |
28 | #else |
29 | #define smp_alt_once 1 | |
30 | #endif | |
31 | ||
32 | static int debug_alternative; | |
b7fb4af0 | 33 | |
d167a518 GH |
34 | static int __init debug_alt(char *str) |
35 | { | |
36 | debug_alternative = 1; | |
37 | return 1; | |
38 | } | |
d167a518 GH |
39 | __setup("debug-alternative", debug_alt); |
40 | ||
09488165 JB |
41 | static int noreplace_smp; |
42 | ||
b7fb4af0 JF |
43 | static int __init setup_noreplace_smp(char *str) |
44 | { | |
45 | noreplace_smp = 1; | |
46 | return 1; | |
47 | } | |
48 | __setup("noreplace-smp", setup_noreplace_smp); | |
49 | ||
959b4fdf JF |
50 | #ifdef CONFIG_PARAVIRT |
51 | static int noreplace_paravirt = 0; | |
52 | ||
53 | static int __init setup_noreplace_paravirt(char *str) | |
54 | { | |
55 | noreplace_paravirt = 1; | |
56 | return 1; | |
57 | } | |
58 | __setup("noreplace-paravirt", setup_noreplace_paravirt); | |
59 | #endif | |
b7fb4af0 | 60 | |
d167a518 GH |
61 | #define DPRINTK(fmt, args...) if (debug_alternative) \ |
62 | printk(KERN_DEBUG fmt, args) | |
63 | ||
64 | #ifdef GENERIC_NOP1 | |
9a0b5817 GH |
65 | /* Use inline assembly to define this because the nops are defined |
66 | as inline assembly strings in the include files and we cannot | |
67 | get them easily into strings. */ | |
121d7bf5 | 68 | asm("\t.section .rodata, \"a\"\nintelnops: " |
9a0b5817 | 69 | GENERIC_NOP1 GENERIC_NOP2 GENERIC_NOP3 GENERIC_NOP4 GENERIC_NOP5 GENERIC_NOP6 |
f4be31ec SR |
70 | GENERIC_NOP7 GENERIC_NOP8 |
71 | "\t.previous"); | |
121d7bf5 JB |
72 | extern const unsigned char intelnops[]; |
73 | static const unsigned char *const intel_nops[ASM_NOP_MAX+1] = { | |
9a0b5817 GH |
74 | NULL, |
75 | intelnops, | |
76 | intelnops + 1, | |
77 | intelnops + 1 + 2, | |
78 | intelnops + 1 + 2 + 3, | |
79 | intelnops + 1 + 2 + 3 + 4, | |
80 | intelnops + 1 + 2 + 3 + 4 + 5, | |
81 | intelnops + 1 + 2 + 3 + 4 + 5 + 6, | |
82 | intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
83 | }; | |
d167a518 GH |
84 | #endif |
85 | ||
86 | #ifdef K8_NOP1 | |
121d7bf5 | 87 | asm("\t.section .rodata, \"a\"\nk8nops: " |
d167a518 | 88 | K8_NOP1 K8_NOP2 K8_NOP3 K8_NOP4 K8_NOP5 K8_NOP6 |
f4be31ec SR |
89 | K8_NOP7 K8_NOP8 |
90 | "\t.previous"); | |
121d7bf5 JB |
91 | extern const unsigned char k8nops[]; |
92 | static const unsigned char *const k8_nops[ASM_NOP_MAX+1] = { | |
9a0b5817 GH |
93 | NULL, |
94 | k8nops, | |
95 | k8nops + 1, | |
96 | k8nops + 1 + 2, | |
97 | k8nops + 1 + 2 + 3, | |
98 | k8nops + 1 + 2 + 3 + 4, | |
99 | k8nops + 1 + 2 + 3 + 4 + 5, | |
100 | k8nops + 1 + 2 + 3 + 4 + 5 + 6, | |
101 | k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
102 | }; | |
d167a518 GH |
103 | #endif |
104 | ||
105 | #ifdef K7_NOP1 | |
121d7bf5 | 106 | asm("\t.section .rodata, \"a\"\nk7nops: " |
d167a518 | 107 | K7_NOP1 K7_NOP2 K7_NOP3 K7_NOP4 K7_NOP5 K7_NOP6 |
f4be31ec SR |
108 | K7_NOP7 K7_NOP8 |
109 | "\t.previous"); | |
121d7bf5 JB |
110 | extern const unsigned char k7nops[]; |
111 | static const unsigned char *const k7_nops[ASM_NOP_MAX+1] = { | |
9a0b5817 GH |
112 | NULL, |
113 | k7nops, | |
114 | k7nops + 1, | |
115 | k7nops + 1 + 2, | |
116 | k7nops + 1 + 2 + 3, | |
117 | k7nops + 1 + 2 + 3 + 4, | |
118 | k7nops + 1 + 2 + 3 + 4 + 5, | |
119 | k7nops + 1 + 2 + 3 + 4 + 5 + 6, | |
120 | k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
121 | }; | |
d167a518 GH |
122 | #endif |
123 | ||
32c464f5 JB |
124 | #ifdef P6_NOP1 |
125 | asm("\t.section .rodata, \"a\"\np6nops: " | |
126 | P6_NOP1 P6_NOP2 P6_NOP3 P6_NOP4 P6_NOP5 P6_NOP6 | |
f4be31ec SR |
127 | P6_NOP7 P6_NOP8 |
128 | "\t.previous"); | |
32c464f5 JB |
129 | extern const unsigned char p6nops[]; |
130 | static const unsigned char *const p6_nops[ASM_NOP_MAX+1] = { | |
131 | NULL, | |
132 | p6nops, | |
133 | p6nops + 1, | |
134 | p6nops + 1 + 2, | |
135 | p6nops + 1 + 2 + 3, | |
136 | p6nops + 1 + 2 + 3 + 4, | |
137 | p6nops + 1 + 2 + 3 + 4 + 5, | |
138 | p6nops + 1 + 2 + 3 + 4 + 5 + 6, | |
139 | p6nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
140 | }; | |
141 | #endif | |
142 | ||
d167a518 GH |
143 | #ifdef CONFIG_X86_64 |
144 | ||
145 | extern char __vsyscall_0; | |
dfa60aba | 146 | const unsigned char *const *find_nop_table(void) |
d167a518 | 147 | { |
f31d731e PA |
148 | if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL && |
149 | boot_cpu_has(X86_FEATURE_NOPL)) | |
150 | return p6_nops; | |
151 | else | |
152 | return k8_nops; | |
d167a518 GH |
153 | } |
154 | ||
155 | #else /* CONFIG_X86_64 */ | |
156 | ||
dfa60aba | 157 | const unsigned char *const *find_nop_table(void) |
9a0b5817 | 158 | { |
f31d731e PA |
159 | if (boot_cpu_has(X86_FEATURE_K8)) |
160 | return k8_nops; | |
161 | else if (boot_cpu_has(X86_FEATURE_K7)) | |
162 | return k7_nops; | |
163 | else if (boot_cpu_has(X86_FEATURE_NOPL)) | |
164 | return p6_nops; | |
165 | else | |
166 | return intel_nops; | |
9a0b5817 GH |
167 | } |
168 | ||
d167a518 GH |
169 | #endif /* CONFIG_X86_64 */ |
170 | ||
ab144f5e | 171 | /* Use this to add nops to a buffer, then text_poke the whole buffer. */ |
e587cadd | 172 | void add_nops(void *insns, unsigned int len) |
139ec7c4 | 173 | { |
121d7bf5 | 174 | const unsigned char *const *noptable = find_nop_table(); |
139ec7c4 RR |
175 | |
176 | while (len > 0) { | |
177 | unsigned int noplen = len; | |
178 | if (noplen > ASM_NOP_MAX) | |
179 | noplen = ASM_NOP_MAX; | |
ab144f5e | 180 | memcpy(insns, noptable[noplen], noplen); |
139ec7c4 RR |
181 | insns += noplen; |
182 | len -= noplen; | |
183 | } | |
184 | } | |
e587cadd | 185 | EXPORT_SYMBOL_GPL(add_nops); |
139ec7c4 | 186 | |
d167a518 | 187 | extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; |
d167a518 GH |
188 | extern u8 *__smp_locks[], *__smp_locks_end[]; |
189 | ||
9a0b5817 GH |
190 | /* Replace instructions with better alternatives for this CPU type. |
191 | This runs before SMP is initialized to avoid SMP problems with | |
192 | self modifying code. This implies that assymetric systems where | |
193 | APs have less capabilities than the boot processor are not handled. | |
194 | Tough. Make sure you disable such features by hand. */ | |
195 | ||
196 | void apply_alternatives(struct alt_instr *start, struct alt_instr *end) | |
197 | { | |
9a0b5817 | 198 | struct alt_instr *a; |
ab144f5e | 199 | char insnbuf[MAX_PATCH_LEN]; |
9a0b5817 | 200 | |
77bf90ed | 201 | DPRINTK("%s: alt table %p -> %p\n", __func__, start, end); |
9a0b5817 | 202 | for (a = start; a < end; a++) { |
ab144f5e | 203 | u8 *instr = a->instr; |
9a0b5817 | 204 | BUG_ON(a->replacementlen > a->instrlen); |
ab144f5e | 205 | BUG_ON(a->instrlen > sizeof(insnbuf)); |
9a0b5817 GH |
206 | if (!boot_cpu_has(a->cpuid)) |
207 | continue; | |
d167a518 GH |
208 | #ifdef CONFIG_X86_64 |
209 | /* vsyscall code is not mapped yet. resolve it manually. */ | |
210 | if (instr >= (u8 *)VSYSCALL_START && instr < (u8*)VSYSCALL_END) { | |
211 | instr = __va(instr - (u8*)VSYSCALL_START + (u8*)__pa_symbol(&__vsyscall_0)); | |
212 | DPRINTK("%s: vsyscall fixup: %p => %p\n", | |
77bf90ed | 213 | __func__, a->instr, instr); |
d167a518 GH |
214 | } |
215 | #endif | |
ab144f5e AK |
216 | memcpy(insnbuf, a->replacement, a->replacementlen); |
217 | add_nops(insnbuf + a->replacementlen, | |
218 | a->instrlen - a->replacementlen); | |
e587cadd | 219 | text_poke_early(instr, insnbuf, a->instrlen); |
9a0b5817 GH |
220 | } |
221 | } | |
222 | ||
8ec4d41f GH |
223 | #ifdef CONFIG_SMP |
224 | ||
9a0b5817 GH |
225 | static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end) |
226 | { | |
227 | u8 **ptr; | |
228 | ||
229 | for (ptr = start; ptr < end; ptr++) { | |
230 | if (*ptr < text) | |
231 | continue; | |
232 | if (*ptr > text_end) | |
233 | continue; | |
f88f07e0 MD |
234 | /* turn DS segment override prefix into lock prefix */ |
235 | text_poke(*ptr, ((unsigned char []){0xf0}), 1); | |
9a0b5817 GH |
236 | }; |
237 | } | |
238 | ||
239 | static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end) | |
240 | { | |
9a0b5817 GH |
241 | u8 **ptr; |
242 | ||
b7fb4af0 JF |
243 | if (noreplace_smp) |
244 | return; | |
245 | ||
9a0b5817 GH |
246 | for (ptr = start; ptr < end; ptr++) { |
247 | if (*ptr < text) | |
248 | continue; | |
249 | if (*ptr > text_end) | |
250 | continue; | |
f88f07e0 MD |
251 | /* turn lock prefix into DS segment override prefix */ |
252 | text_poke(*ptr, ((unsigned char []){0x3E}), 1); | |
9a0b5817 GH |
253 | }; |
254 | } | |
255 | ||
256 | struct smp_alt_module { | |
257 | /* what is this ??? */ | |
258 | struct module *mod; | |
259 | char *name; | |
260 | ||
261 | /* ptrs to lock prefixes */ | |
262 | u8 **locks; | |
263 | u8 **locks_end; | |
264 | ||
265 | /* .text segment, needed to avoid patching init code ;) */ | |
266 | u8 *text; | |
267 | u8 *text_end; | |
268 | ||
269 | struct list_head next; | |
270 | }; | |
271 | static LIST_HEAD(smp_alt_modules); | |
2f1dafe5 | 272 | static DEFINE_MUTEX(smp_alt); |
ca74a6f8 | 273 | static int smp_mode = 1; /* protected by smp_alt */ |
9a0b5817 | 274 | |
9a0b5817 GH |
275 | void alternatives_smp_module_add(struct module *mod, char *name, |
276 | void *locks, void *locks_end, | |
277 | void *text, void *text_end) | |
278 | { | |
279 | struct smp_alt_module *smp; | |
9a0b5817 | 280 | |
b7fb4af0 JF |
281 | if (noreplace_smp) |
282 | return; | |
283 | ||
9a0b5817 GH |
284 | if (smp_alt_once) { |
285 | if (boot_cpu_has(X86_FEATURE_UP)) | |
286 | alternatives_smp_unlock(locks, locks_end, | |
287 | text, text_end); | |
288 | return; | |
289 | } | |
290 | ||
291 | smp = kzalloc(sizeof(*smp), GFP_KERNEL); | |
292 | if (NULL == smp) | |
293 | return; /* we'll run the (safe but slow) SMP code then ... */ | |
294 | ||
295 | smp->mod = mod; | |
296 | smp->name = name; | |
297 | smp->locks = locks; | |
298 | smp->locks_end = locks_end; | |
299 | smp->text = text; | |
300 | smp->text_end = text_end; | |
301 | DPRINTK("%s: locks %p -> %p, text %p -> %p, name %s\n", | |
77bf90ed | 302 | __func__, smp->locks, smp->locks_end, |
9a0b5817 GH |
303 | smp->text, smp->text_end, smp->name); |
304 | ||
2f1dafe5 | 305 | mutex_lock(&smp_alt); |
9a0b5817 GH |
306 | list_add_tail(&smp->next, &smp_alt_modules); |
307 | if (boot_cpu_has(X86_FEATURE_UP)) | |
308 | alternatives_smp_unlock(smp->locks, smp->locks_end, | |
309 | smp->text, smp->text_end); | |
2f1dafe5 | 310 | mutex_unlock(&smp_alt); |
9a0b5817 GH |
311 | } |
312 | ||
313 | void alternatives_smp_module_del(struct module *mod) | |
314 | { | |
315 | struct smp_alt_module *item; | |
9a0b5817 | 316 | |
b7fb4af0 | 317 | if (smp_alt_once || noreplace_smp) |
9a0b5817 GH |
318 | return; |
319 | ||
2f1dafe5 | 320 | mutex_lock(&smp_alt); |
9a0b5817 GH |
321 | list_for_each_entry(item, &smp_alt_modules, next) { |
322 | if (mod != item->mod) | |
323 | continue; | |
324 | list_del(&item->next); | |
2f1dafe5 | 325 | mutex_unlock(&smp_alt); |
77bf90ed | 326 | DPRINTK("%s: %s\n", __func__, item->name); |
9a0b5817 GH |
327 | kfree(item); |
328 | return; | |
329 | } | |
2f1dafe5 | 330 | mutex_unlock(&smp_alt); |
9a0b5817 GH |
331 | } |
332 | ||
333 | void alternatives_smp_switch(int smp) | |
334 | { | |
335 | struct smp_alt_module *mod; | |
9a0b5817 | 336 | |
3047e99e IM |
337 | #ifdef CONFIG_LOCKDEP |
338 | /* | |
17abecfe IM |
339 | * Older binutils section handling bug prevented |
340 | * alternatives-replacement from working reliably. | |
341 | * | |
342 | * If this still occurs then you should see a hang | |
343 | * or crash shortly after this line: | |
3047e99e | 344 | */ |
17abecfe | 345 | printk("lockdep: fixing up alternatives.\n"); |
3047e99e IM |
346 | #endif |
347 | ||
b7fb4af0 | 348 | if (noreplace_smp || smp_alt_once) |
9a0b5817 GH |
349 | return; |
350 | BUG_ON(!smp && (num_online_cpus() > 1)); | |
351 | ||
2f1dafe5 | 352 | mutex_lock(&smp_alt); |
ca74a6f8 AK |
353 | |
354 | /* | |
355 | * Avoid unnecessary switches because it forces JIT based VMs to | |
356 | * throw away all cached translations, which can be quite costly. | |
357 | */ | |
358 | if (smp == smp_mode) { | |
359 | /* nothing */ | |
360 | } else if (smp) { | |
9a0b5817 | 361 | printk(KERN_INFO "SMP alternatives: switching to SMP code\n"); |
53756d37 JF |
362 | clear_cpu_cap(&boot_cpu_data, X86_FEATURE_UP); |
363 | clear_cpu_cap(&cpu_data(0), X86_FEATURE_UP); | |
9a0b5817 GH |
364 | list_for_each_entry(mod, &smp_alt_modules, next) |
365 | alternatives_smp_lock(mod->locks, mod->locks_end, | |
366 | mod->text, mod->text_end); | |
367 | } else { | |
368 | printk(KERN_INFO "SMP alternatives: switching to UP code\n"); | |
53756d37 JF |
369 | set_cpu_cap(&boot_cpu_data, X86_FEATURE_UP); |
370 | set_cpu_cap(&cpu_data(0), X86_FEATURE_UP); | |
9a0b5817 GH |
371 | list_for_each_entry(mod, &smp_alt_modules, next) |
372 | alternatives_smp_unlock(mod->locks, mod->locks_end, | |
373 | mod->text, mod->text_end); | |
374 | } | |
ca74a6f8 | 375 | smp_mode = smp; |
2f1dafe5 | 376 | mutex_unlock(&smp_alt); |
9a0b5817 GH |
377 | } |
378 | ||
8ec4d41f GH |
379 | #endif |
380 | ||
139ec7c4 | 381 | #ifdef CONFIG_PARAVIRT |
98de032b JF |
382 | void apply_paravirt(struct paravirt_patch_site *start, |
383 | struct paravirt_patch_site *end) | |
139ec7c4 | 384 | { |
98de032b | 385 | struct paravirt_patch_site *p; |
ab144f5e | 386 | char insnbuf[MAX_PATCH_LEN]; |
139ec7c4 | 387 | |
959b4fdf JF |
388 | if (noreplace_paravirt) |
389 | return; | |
390 | ||
139ec7c4 RR |
391 | for (p = start; p < end; p++) { |
392 | unsigned int used; | |
393 | ||
ab144f5e | 394 | BUG_ON(p->len > MAX_PATCH_LEN); |
d34fda4a CW |
395 | /* prep the buffer with the original instructions */ |
396 | memcpy(insnbuf, p->instr, p->len); | |
93b1eab3 JF |
397 | used = pv_init_ops.patch(p->instrtype, p->clobbers, insnbuf, |
398 | (unsigned long)p->instr, p->len); | |
7f63c41c | 399 | |
63f70270 JF |
400 | BUG_ON(used > p->len); |
401 | ||
139ec7c4 | 402 | /* Pad the rest with nops */ |
ab144f5e | 403 | add_nops(insnbuf + used, p->len - used); |
e587cadd | 404 | text_poke_early(p->instr, insnbuf, p->len); |
139ec7c4 | 405 | } |
139ec7c4 | 406 | } |
98de032b | 407 | extern struct paravirt_patch_site __start_parainstructions[], |
139ec7c4 RR |
408 | __stop_parainstructions[]; |
409 | #endif /* CONFIG_PARAVIRT */ | |
410 | ||
9a0b5817 GH |
411 | void __init alternative_instructions(void) |
412 | { | |
8f4e956b AK |
413 | /* The patching is not fully atomic, so try to avoid local interruptions |
414 | that might execute the to be patched code. | |
415 | Other CPUs are not running. */ | |
416 | stop_nmi(); | |
123aa76e AK |
417 | |
418 | /* | |
419 | * Don't stop machine check exceptions while patching. | |
420 | * MCEs only happen when something got corrupted and in this | |
421 | * case we must do something about the corruption. | |
422 | * Ignoring it is worse than a unlikely patching race. | |
423 | * Also machine checks tend to be broadcast and if one CPU | |
424 | * goes into machine check the others follow quickly, so we don't | |
425 | * expect a machine check to cause undue problems during to code | |
426 | * patching. | |
427 | */ | |
8f4e956b | 428 | |
9a0b5817 GH |
429 | apply_alternatives(__alt_instructions, __alt_instructions_end); |
430 | ||
431 | /* switch to patch-once-at-boottime-only mode and free the | |
432 | * tables in case we know the number of CPUs will never ever | |
433 | * change */ | |
434 | #ifdef CONFIG_HOTPLUG_CPU | |
435 | if (num_possible_cpus() < 2) | |
436 | smp_alt_once = 1; | |
9a0b5817 GH |
437 | #endif |
438 | ||
8ec4d41f | 439 | #ifdef CONFIG_SMP |
9a0b5817 GH |
440 | if (smp_alt_once) { |
441 | if (1 == num_possible_cpus()) { | |
442 | printk(KERN_INFO "SMP alternatives: switching to UP code\n"); | |
53756d37 JF |
443 | set_cpu_cap(&boot_cpu_data, X86_FEATURE_UP); |
444 | set_cpu_cap(&cpu_data(0), X86_FEATURE_UP); | |
445 | ||
9a0b5817 GH |
446 | alternatives_smp_unlock(__smp_locks, __smp_locks_end, |
447 | _text, _etext); | |
448 | } | |
9a0b5817 | 449 | } else { |
9a0b5817 GH |
450 | alternatives_smp_module_add(NULL, "core kernel", |
451 | __smp_locks, __smp_locks_end, | |
452 | _text, _etext); | |
ca74a6f8 AK |
453 | |
454 | /* Only switch to UP mode if we don't immediately boot others */ | |
649c6653 | 455 | if (num_present_cpus() == 1 || setup_max_cpus <= 1) |
ca74a6f8 | 456 | alternatives_smp_switch(0); |
9a0b5817 | 457 | } |
8ec4d41f | 458 | #endif |
441d40dc | 459 | apply_paravirt(__parainstructions, __parainstructions_end); |
8f4e956b | 460 | |
f68fd5f4 FW |
461 | if (smp_alt_once) |
462 | free_init_pages("SMP alternatives", | |
463 | (unsigned long)__smp_locks, | |
464 | (unsigned long)__smp_locks_end); | |
465 | ||
8f4e956b | 466 | restart_nmi(); |
9a0b5817 | 467 | } |
19d36ccd | 468 | |
e587cadd MD |
469 | /** |
470 | * text_poke_early - Update instructions on a live kernel at boot time | |
471 | * @addr: address to modify | |
472 | * @opcode: source of the copy | |
473 | * @len: length to copy | |
474 | * | |
19d36ccd AK |
475 | * When you use this code to patch more than one byte of an instruction |
476 | * you need to make sure that other CPUs cannot execute this code in parallel. | |
e587cadd MD |
477 | * Also no thread must be currently preempted in the middle of these |
478 | * instructions. And on the local CPU you need to be protected again NMI or MCE | |
479 | * handlers seeing an inconsistent instruction while you patch. | |
19d36ccd | 480 | */ |
e587cadd | 481 | void *text_poke_early(void *addr, const void *opcode, size_t len) |
19d36ccd | 482 | { |
e587cadd MD |
483 | unsigned long flags; |
484 | local_irq_save(flags); | |
19d36ccd | 485 | memcpy(addr, opcode, len); |
e587cadd MD |
486 | local_irq_restore(flags); |
487 | sync_core(); | |
488 | /* Could also do a CLFLUSH here to speed up CPU recovery; but | |
489 | that causes hangs on some VIA CPUs. */ | |
490 | return addr; | |
491 | } | |
492 | ||
493 | /** | |
494 | * text_poke - Update instructions on a live kernel | |
495 | * @addr: address to modify | |
496 | * @opcode: source of the copy | |
497 | * @len: length to copy | |
498 | * | |
499 | * Only atomic text poke/set should be allowed when not doing early patching. | |
500 | * It means the size must be writable atomically and the address must be aligned | |
501 | * in a way that permits an atomic write. It also makes sure we fit on a single | |
502 | * page. | |
503 | */ | |
504 | void *__kprobes text_poke(void *addr, const void *opcode, size_t len) | |
505 | { | |
e587cadd MD |
506 | char *vaddr; |
507 | int nr_pages = 2; | |
b7b66baa MD |
508 | struct page *pages[2]; |
509 | int i; | |
e587cadd | 510 | |
34754b69 | 511 | might_sleep(); |
b7b66baa MD |
512 | if (!core_kernel_text((unsigned long)addr)) { |
513 | pages[0] = vmalloc_to_page(addr); | |
514 | pages[1] = vmalloc_to_page(addr + PAGE_SIZE); | |
15a601eb | 515 | } else { |
b7b66baa | 516 | pages[0] = virt_to_page(addr); |
00c6b2d5 | 517 | WARN_ON(!PageReserved(pages[0])); |
b7b66baa | 518 | pages[1] = virt_to_page(addr + PAGE_SIZE); |
e587cadd | 519 | } |
b7b66baa MD |
520 | BUG_ON(!pages[0]); |
521 | if (!pages[1]) | |
522 | nr_pages = 1; | |
523 | vaddr = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL); | |
524 | BUG_ON(!vaddr); | |
34754b69 | 525 | local_irq_disable(); |
b7b66baa | 526 | memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len); |
34754b69 | 527 | local_irq_enable(); |
b7b66baa | 528 | vunmap(vaddr); |
19d36ccd | 529 | sync_core(); |
a534b679 AK |
530 | /* Could also do a CLFLUSH here to speed up CPU recovery; but |
531 | that causes hangs on some VIA CPUs. */ | |
b7b66baa MD |
532 | for (i = 0; i < len; i++) |
533 | BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]); | |
e587cadd | 534 | return addr; |
19d36ccd | 535 | } |