Commit | Line | Data |
---|---|---|
9a0b5817 | 1 | #include <linux/module.h> |
f6a57033 | 2 | #include <linux/sched.h> |
9a0b5817 GH |
3 | #include <linux/spinlock.h> |
4 | #include <linux/list.h> | |
5 | #include <asm/alternative.h> | |
6 | #include <asm/sections.h> | |
7 | ||
b7fb4af0 | 8 | static int noreplace_smp = 0; |
d167a518 GH |
9 | static int smp_alt_once = 0; |
10 | static int debug_alternative = 0; | |
9a0b5817 | 11 | |
d167a518 GH |
12 | static int __init bootonly(char *str) |
13 | { | |
14 | smp_alt_once = 1; | |
15 | return 1; | |
16 | } | |
b7fb4af0 JF |
17 | __setup("smp-alt-boot", bootonly); |
18 | ||
d167a518 GH |
19 | static int __init debug_alt(char *str) |
20 | { | |
21 | debug_alternative = 1; | |
22 | return 1; | |
23 | } | |
d167a518 GH |
24 | __setup("debug-alternative", debug_alt); |
25 | ||
b7fb4af0 JF |
26 | static int __init setup_noreplace_smp(char *str) |
27 | { | |
28 | noreplace_smp = 1; | |
29 | return 1; | |
30 | } | |
31 | __setup("noreplace-smp", setup_noreplace_smp); | |
32 | ||
959b4fdf JF |
33 | #ifdef CONFIG_PARAVIRT |
34 | static int noreplace_paravirt = 0; | |
35 | ||
36 | static int __init setup_noreplace_paravirt(char *str) | |
37 | { | |
38 | noreplace_paravirt = 1; | |
39 | return 1; | |
40 | } | |
41 | __setup("noreplace-paravirt", setup_noreplace_paravirt); | |
42 | #endif | |
b7fb4af0 | 43 | |
d167a518 GH |
44 | #define DPRINTK(fmt, args...) if (debug_alternative) \ |
45 | printk(KERN_DEBUG fmt, args) | |
46 | ||
47 | #ifdef GENERIC_NOP1 | |
9a0b5817 GH |
48 | /* Use inline assembly to define this because the nops are defined |
49 | as inline assembly strings in the include files and we cannot | |
50 | get them easily into strings. */ | |
51 | asm("\t.data\nintelnops: " | |
52 | GENERIC_NOP1 GENERIC_NOP2 GENERIC_NOP3 GENERIC_NOP4 GENERIC_NOP5 GENERIC_NOP6 | |
53 | GENERIC_NOP7 GENERIC_NOP8); | |
d167a518 | 54 | extern unsigned char intelnops[]; |
9a0b5817 GH |
55 | static unsigned char *intel_nops[ASM_NOP_MAX+1] = { |
56 | NULL, | |
57 | intelnops, | |
58 | intelnops + 1, | |
59 | intelnops + 1 + 2, | |
60 | intelnops + 1 + 2 + 3, | |
61 | intelnops + 1 + 2 + 3 + 4, | |
62 | intelnops + 1 + 2 + 3 + 4 + 5, | |
63 | intelnops + 1 + 2 + 3 + 4 + 5 + 6, | |
64 | intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
65 | }; | |
d167a518 GH |
66 | #endif |
67 | ||
68 | #ifdef K8_NOP1 | |
69 | asm("\t.data\nk8nops: " | |
70 | K8_NOP1 K8_NOP2 K8_NOP3 K8_NOP4 K8_NOP5 K8_NOP6 | |
71 | K8_NOP7 K8_NOP8); | |
72 | extern unsigned char k8nops[]; | |
9a0b5817 GH |
73 | static unsigned char *k8_nops[ASM_NOP_MAX+1] = { |
74 | NULL, | |
75 | k8nops, | |
76 | k8nops + 1, | |
77 | k8nops + 1 + 2, | |
78 | k8nops + 1 + 2 + 3, | |
79 | k8nops + 1 + 2 + 3 + 4, | |
80 | k8nops + 1 + 2 + 3 + 4 + 5, | |
81 | k8nops + 1 + 2 + 3 + 4 + 5 + 6, | |
82 | k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
83 | }; | |
d167a518 GH |
84 | #endif |
85 | ||
86 | #ifdef K7_NOP1 | |
87 | asm("\t.data\nk7nops: " | |
88 | K7_NOP1 K7_NOP2 K7_NOP3 K7_NOP4 K7_NOP5 K7_NOP6 | |
89 | K7_NOP7 K7_NOP8); | |
90 | extern unsigned char k7nops[]; | |
9a0b5817 GH |
91 | static unsigned char *k7_nops[ASM_NOP_MAX+1] = { |
92 | NULL, | |
93 | k7nops, | |
94 | k7nops + 1, | |
95 | k7nops + 1 + 2, | |
96 | k7nops + 1 + 2 + 3, | |
97 | k7nops + 1 + 2 + 3 + 4, | |
98 | k7nops + 1 + 2 + 3 + 4 + 5, | |
99 | k7nops + 1 + 2 + 3 + 4 + 5 + 6, | |
100 | k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, | |
101 | }; | |
d167a518 GH |
102 | #endif |
103 | ||
104 | #ifdef CONFIG_X86_64 | |
105 | ||
106 | extern char __vsyscall_0; | |
107 | static inline unsigned char** find_nop_table(void) | |
108 | { | |
109 | return k8_nops; | |
110 | } | |
111 | ||
112 | #else /* CONFIG_X86_64 */ | |
113 | ||
9a0b5817 GH |
114 | static struct nop { |
115 | int cpuid; | |
116 | unsigned char **noptable; | |
117 | } noptypes[] = { | |
118 | { X86_FEATURE_K8, k8_nops }, | |
119 | { X86_FEATURE_K7, k7_nops }, | |
120 | { -1, NULL } | |
121 | }; | |
122 | ||
9a0b5817 GH |
123 | static unsigned char** find_nop_table(void) |
124 | { | |
125 | unsigned char **noptable = intel_nops; | |
126 | int i; | |
127 | ||
128 | for (i = 0; noptypes[i].cpuid >= 0; i++) { | |
129 | if (boot_cpu_has(noptypes[i].cpuid)) { | |
130 | noptable = noptypes[i].noptable; | |
131 | break; | |
132 | } | |
133 | } | |
134 | return noptable; | |
135 | } | |
136 | ||
d167a518 GH |
137 | #endif /* CONFIG_X86_64 */ |
138 | ||
139ec7c4 RR |
139 | static void nop_out(void *insns, unsigned int len) |
140 | { | |
141 | unsigned char **noptable = find_nop_table(); | |
142 | ||
143 | while (len > 0) { | |
144 | unsigned int noplen = len; | |
145 | if (noplen > ASM_NOP_MAX) | |
146 | noplen = ASM_NOP_MAX; | |
147 | memcpy(insns, noptable[noplen], noplen); | |
148 | insns += noplen; | |
149 | len -= noplen; | |
150 | } | |
151 | } | |
152 | ||
d167a518 | 153 | extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; |
d167a518 GH |
154 | extern u8 *__smp_locks[], *__smp_locks_end[]; |
155 | ||
9a0b5817 GH |
156 | /* Replace instructions with better alternatives for this CPU type. |
157 | This runs before SMP is initialized to avoid SMP problems with | |
158 | self modifying code. This implies that assymetric systems where | |
159 | APs have less capabilities than the boot processor are not handled. | |
160 | Tough. Make sure you disable such features by hand. */ | |
161 | ||
162 | void apply_alternatives(struct alt_instr *start, struct alt_instr *end) | |
163 | { | |
9a0b5817 | 164 | struct alt_instr *a; |
d167a518 | 165 | u8 *instr; |
139ec7c4 | 166 | int diff; |
9a0b5817 GH |
167 | |
168 | DPRINTK("%s: alt table %p -> %p\n", __FUNCTION__, start, end); | |
169 | for (a = start; a < end; a++) { | |
170 | BUG_ON(a->replacementlen > a->instrlen); | |
171 | if (!boot_cpu_has(a->cpuid)) | |
172 | continue; | |
d167a518 GH |
173 | instr = a->instr; |
174 | #ifdef CONFIG_X86_64 | |
175 | /* vsyscall code is not mapped yet. resolve it manually. */ | |
176 | if (instr >= (u8 *)VSYSCALL_START && instr < (u8*)VSYSCALL_END) { | |
177 | instr = __va(instr - (u8*)VSYSCALL_START + (u8*)__pa_symbol(&__vsyscall_0)); | |
178 | DPRINTK("%s: vsyscall fixup: %p => %p\n", | |
179 | __FUNCTION__, a->instr, instr); | |
180 | } | |
181 | #endif | |
182 | memcpy(instr, a->replacement, a->replacementlen); | |
9a0b5817 | 183 | diff = a->instrlen - a->replacementlen; |
139ec7c4 | 184 | nop_out(instr + a->replacementlen, diff); |
9a0b5817 GH |
185 | } |
186 | } | |
187 | ||
8ec4d41f GH |
188 | #ifdef CONFIG_SMP |
189 | ||
9a0b5817 GH |
190 | static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end) |
191 | { | |
192 | u8 **ptr; | |
193 | ||
194 | for (ptr = start; ptr < end; ptr++) { | |
195 | if (*ptr < text) | |
196 | continue; | |
197 | if (*ptr > text_end) | |
198 | continue; | |
199 | **ptr = 0xf0; /* lock prefix */ | |
200 | }; | |
201 | } | |
202 | ||
203 | static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end) | |
204 | { | |
9a0b5817 GH |
205 | u8 **ptr; |
206 | ||
b7fb4af0 JF |
207 | if (noreplace_smp) |
208 | return; | |
209 | ||
9a0b5817 GH |
210 | for (ptr = start; ptr < end; ptr++) { |
211 | if (*ptr < text) | |
212 | continue; | |
213 | if (*ptr > text_end) | |
214 | continue; | |
139ec7c4 | 215 | nop_out(*ptr, 1); |
9a0b5817 GH |
216 | }; |
217 | } | |
218 | ||
219 | struct smp_alt_module { | |
220 | /* what is this ??? */ | |
221 | struct module *mod; | |
222 | char *name; | |
223 | ||
224 | /* ptrs to lock prefixes */ | |
225 | u8 **locks; | |
226 | u8 **locks_end; | |
227 | ||
228 | /* .text segment, needed to avoid patching init code ;) */ | |
229 | u8 *text; | |
230 | u8 *text_end; | |
231 | ||
232 | struct list_head next; | |
233 | }; | |
234 | static LIST_HEAD(smp_alt_modules); | |
235 | static DEFINE_SPINLOCK(smp_alt); | |
236 | ||
9a0b5817 GH |
237 | void alternatives_smp_module_add(struct module *mod, char *name, |
238 | void *locks, void *locks_end, | |
239 | void *text, void *text_end) | |
240 | { | |
241 | struct smp_alt_module *smp; | |
242 | unsigned long flags; | |
243 | ||
b7fb4af0 JF |
244 | if (noreplace_smp) |
245 | return; | |
246 | ||
9a0b5817 GH |
247 | if (smp_alt_once) { |
248 | if (boot_cpu_has(X86_FEATURE_UP)) | |
249 | alternatives_smp_unlock(locks, locks_end, | |
250 | text, text_end); | |
251 | return; | |
252 | } | |
253 | ||
254 | smp = kzalloc(sizeof(*smp), GFP_KERNEL); | |
255 | if (NULL == smp) | |
256 | return; /* we'll run the (safe but slow) SMP code then ... */ | |
257 | ||
258 | smp->mod = mod; | |
259 | smp->name = name; | |
260 | smp->locks = locks; | |
261 | smp->locks_end = locks_end; | |
262 | smp->text = text; | |
263 | smp->text_end = text_end; | |
264 | DPRINTK("%s: locks %p -> %p, text %p -> %p, name %s\n", | |
265 | __FUNCTION__, smp->locks, smp->locks_end, | |
266 | smp->text, smp->text_end, smp->name); | |
267 | ||
268 | spin_lock_irqsave(&smp_alt, flags); | |
269 | list_add_tail(&smp->next, &smp_alt_modules); | |
270 | if (boot_cpu_has(X86_FEATURE_UP)) | |
271 | alternatives_smp_unlock(smp->locks, smp->locks_end, | |
272 | smp->text, smp->text_end); | |
273 | spin_unlock_irqrestore(&smp_alt, flags); | |
274 | } | |
275 | ||
276 | void alternatives_smp_module_del(struct module *mod) | |
277 | { | |
278 | struct smp_alt_module *item; | |
279 | unsigned long flags; | |
280 | ||
b7fb4af0 | 281 | if (smp_alt_once || noreplace_smp) |
9a0b5817 GH |
282 | return; |
283 | ||
284 | spin_lock_irqsave(&smp_alt, flags); | |
285 | list_for_each_entry(item, &smp_alt_modules, next) { | |
286 | if (mod != item->mod) | |
287 | continue; | |
288 | list_del(&item->next); | |
289 | spin_unlock_irqrestore(&smp_alt, flags); | |
290 | DPRINTK("%s: %s\n", __FUNCTION__, item->name); | |
291 | kfree(item); | |
292 | return; | |
293 | } | |
294 | spin_unlock_irqrestore(&smp_alt, flags); | |
295 | } | |
296 | ||
297 | void alternatives_smp_switch(int smp) | |
298 | { | |
299 | struct smp_alt_module *mod; | |
300 | unsigned long flags; | |
301 | ||
3047e99e IM |
302 | #ifdef CONFIG_LOCKDEP |
303 | /* | |
304 | * A not yet fixed binutils section handling bug prevents | |
305 | * alternatives-replacement from working reliably, so turn | |
306 | * it off: | |
307 | */ | |
308 | printk("lockdep: not fixing up alternatives.\n"); | |
309 | return; | |
310 | #endif | |
311 | ||
b7fb4af0 | 312 | if (noreplace_smp || smp_alt_once) |
9a0b5817 GH |
313 | return; |
314 | BUG_ON(!smp && (num_online_cpus() > 1)); | |
315 | ||
316 | spin_lock_irqsave(&smp_alt, flags); | |
317 | if (smp) { | |
318 | printk(KERN_INFO "SMP alternatives: switching to SMP code\n"); | |
319 | clear_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability); | |
320 | clear_bit(X86_FEATURE_UP, cpu_data[0].x86_capability); | |
9a0b5817 GH |
321 | list_for_each_entry(mod, &smp_alt_modules, next) |
322 | alternatives_smp_lock(mod->locks, mod->locks_end, | |
323 | mod->text, mod->text_end); | |
324 | } else { | |
325 | printk(KERN_INFO "SMP alternatives: switching to UP code\n"); | |
326 | set_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability); | |
327 | set_bit(X86_FEATURE_UP, cpu_data[0].x86_capability); | |
9a0b5817 GH |
328 | list_for_each_entry(mod, &smp_alt_modules, next) |
329 | alternatives_smp_unlock(mod->locks, mod->locks_end, | |
330 | mod->text, mod->text_end); | |
331 | } | |
332 | spin_unlock_irqrestore(&smp_alt, flags); | |
333 | } | |
334 | ||
8ec4d41f GH |
335 | #endif |
336 | ||
139ec7c4 | 337 | #ifdef CONFIG_PARAVIRT |
98de032b JF |
338 | void apply_paravirt(struct paravirt_patch_site *start, |
339 | struct paravirt_patch_site *end) | |
139ec7c4 | 340 | { |
98de032b | 341 | struct paravirt_patch_site *p; |
139ec7c4 | 342 | |
959b4fdf JF |
343 | if (noreplace_paravirt) |
344 | return; | |
345 | ||
139ec7c4 RR |
346 | for (p = start; p < end; p++) { |
347 | unsigned int used; | |
348 | ||
349 | used = paravirt_ops.patch(p->instrtype, p->clobbers, p->instr, | |
350 | p->len); | |
7f63c41c | 351 | |
63f70270 JF |
352 | BUG_ON(used > p->len); |
353 | ||
139ec7c4 RR |
354 | /* Pad the rest with nops */ |
355 | nop_out(p->instr + used, p->len - used); | |
356 | } | |
357 | ||
63f70270 JF |
358 | /* Sync to be conservative, in case we patched following |
359 | * instructions */ | |
139ec7c4 RR |
360 | sync_core(); |
361 | } | |
98de032b | 362 | extern struct paravirt_patch_site __start_parainstructions[], |
139ec7c4 RR |
363 | __stop_parainstructions[]; |
364 | #endif /* CONFIG_PARAVIRT */ | |
365 | ||
9a0b5817 GH |
366 | void __init alternative_instructions(void) |
367 | { | |
e51959fa | 368 | unsigned long flags; |
e51959fa ZA |
369 | |
370 | local_irq_save(flags); | |
9a0b5817 GH |
371 | apply_alternatives(__alt_instructions, __alt_instructions_end); |
372 | ||
373 | /* switch to patch-once-at-boottime-only mode and free the | |
374 | * tables in case we know the number of CPUs will never ever | |
375 | * change */ | |
376 | #ifdef CONFIG_HOTPLUG_CPU | |
377 | if (num_possible_cpus() < 2) | |
378 | smp_alt_once = 1; | |
379 | #else | |
380 | smp_alt_once = 1; | |
381 | #endif | |
382 | ||
8ec4d41f | 383 | #ifdef CONFIG_SMP |
9a0b5817 GH |
384 | if (smp_alt_once) { |
385 | if (1 == num_possible_cpus()) { | |
386 | printk(KERN_INFO "SMP alternatives: switching to UP code\n"); | |
387 | set_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability); | |
388 | set_bit(X86_FEATURE_UP, cpu_data[0].x86_capability); | |
9a0b5817 GH |
389 | alternatives_smp_unlock(__smp_locks, __smp_locks_end, |
390 | _text, _etext); | |
391 | } | |
392 | free_init_pages("SMP alternatives", | |
e3ebadd9 LT |
393 | (unsigned long)__smp_locks, |
394 | (unsigned long)__smp_locks_end); | |
9a0b5817 | 395 | } else { |
9a0b5817 GH |
396 | alternatives_smp_module_add(NULL, "core kernel", |
397 | __smp_locks, __smp_locks_end, | |
398 | _text, _etext); | |
399 | alternatives_smp_switch(0); | |
400 | } | |
8ec4d41f | 401 | #endif |
441d40dc | 402 | apply_paravirt(__parainstructions, __parainstructions_end); |
e51959fa | 403 | local_irq_restore(flags); |
9a0b5817 | 404 | } |