Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 1 | #include <linux/module.h> |
| 2 | #include <linux/spinlock.h> |
| 3 | #include <linux/list.h> |
| 4 | #include <asm/alternative.h> |
| 5 | #include <asm/sections.h> |
| 6 | |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 7 | static int no_replacement = 0; |
| 8 | static int smp_alt_once = 0; |
| 9 | static int debug_alternative = 0; |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 10 | |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 11 | static int __init noreplacement_setup(char *s) |
| 12 | { |
| 13 | no_replacement = 1; |
| 14 | return 1; |
| 15 | } |
| 16 | static int __init bootonly(char *str) |
| 17 | { |
| 18 | smp_alt_once = 1; |
| 19 | return 1; |
| 20 | } |
| 21 | static int __init debug_alt(char *str) |
| 22 | { |
| 23 | debug_alternative = 1; |
| 24 | return 1; |
| 25 | } |
| 26 | |
| 27 | __setup("noreplacement", noreplacement_setup); |
| 28 | __setup("smp-alt-boot", bootonly); |
| 29 | __setup("debug-alternative", debug_alt); |
| 30 | |
| 31 | #define DPRINTK(fmt, args...) if (debug_alternative) \ |
| 32 | printk(KERN_DEBUG fmt, args) |
| 33 | |
| 34 | #ifdef GENERIC_NOP1 |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 35 | /* Use inline assembly to define this because the nops are defined |
| 36 | as inline assembly strings in the include files and we cannot |
| 37 | get them easily into strings. */ |
| 38 | asm("\t.data\nintelnops: " |
| 39 | GENERIC_NOP1 GENERIC_NOP2 GENERIC_NOP3 GENERIC_NOP4 GENERIC_NOP5 GENERIC_NOP6 |
| 40 | GENERIC_NOP7 GENERIC_NOP8); |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 41 | extern unsigned char intelnops[]; |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 42 | static unsigned char *intel_nops[ASM_NOP_MAX+1] = { |
| 43 | NULL, |
| 44 | intelnops, |
| 45 | intelnops + 1, |
| 46 | intelnops + 1 + 2, |
| 47 | intelnops + 1 + 2 + 3, |
| 48 | intelnops + 1 + 2 + 3 + 4, |
| 49 | intelnops + 1 + 2 + 3 + 4 + 5, |
| 50 | intelnops + 1 + 2 + 3 + 4 + 5 + 6, |
| 51 | intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7, |
| 52 | }; |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 53 | #endif |
| 54 | |
| 55 | #ifdef K8_NOP1 |
| 56 | asm("\t.data\nk8nops: " |
| 57 | K8_NOP1 K8_NOP2 K8_NOP3 K8_NOP4 K8_NOP5 K8_NOP6 |
| 58 | K8_NOP7 K8_NOP8); |
| 59 | extern unsigned char k8nops[]; |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 60 | static unsigned char *k8_nops[ASM_NOP_MAX+1] = { |
| 61 | NULL, |
| 62 | k8nops, |
| 63 | k8nops + 1, |
| 64 | k8nops + 1 + 2, |
| 65 | k8nops + 1 + 2 + 3, |
| 66 | k8nops + 1 + 2 + 3 + 4, |
| 67 | k8nops + 1 + 2 + 3 + 4 + 5, |
| 68 | k8nops + 1 + 2 + 3 + 4 + 5 + 6, |
| 69 | k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, |
| 70 | }; |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 71 | #endif |
| 72 | |
| 73 | #ifdef K7_NOP1 |
| 74 | asm("\t.data\nk7nops: " |
| 75 | K7_NOP1 K7_NOP2 K7_NOP3 K7_NOP4 K7_NOP5 K7_NOP6 |
| 76 | K7_NOP7 K7_NOP8); |
| 77 | extern unsigned char k7nops[]; |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 78 | static unsigned char *k7_nops[ASM_NOP_MAX+1] = { |
| 79 | NULL, |
| 80 | k7nops, |
| 81 | k7nops + 1, |
| 82 | k7nops + 1 + 2, |
| 83 | k7nops + 1 + 2 + 3, |
| 84 | k7nops + 1 + 2 + 3 + 4, |
| 85 | k7nops + 1 + 2 + 3 + 4 + 5, |
| 86 | k7nops + 1 + 2 + 3 + 4 + 5 + 6, |
| 87 | k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, |
| 88 | }; |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 89 | #endif |
| 90 | |
| 91 | #ifdef CONFIG_X86_64 |
| 92 | |
| 93 | extern char __vsyscall_0; |
| 94 | static inline unsigned char** find_nop_table(void) |
| 95 | { |
| 96 | return k8_nops; |
| 97 | } |
| 98 | |
| 99 | #else /* CONFIG_X86_64 */ |
| 100 | |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 101 | static struct nop { |
| 102 | int cpuid; |
| 103 | unsigned char **noptable; |
| 104 | } noptypes[] = { |
| 105 | { X86_FEATURE_K8, k8_nops }, |
| 106 | { X86_FEATURE_K7, k7_nops }, |
| 107 | { -1, NULL } |
| 108 | }; |
| 109 | |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 110 | static unsigned char** find_nop_table(void) |
| 111 | { |
| 112 | unsigned char **noptable = intel_nops; |
| 113 | int i; |
| 114 | |
| 115 | for (i = 0; noptypes[i].cpuid >= 0; i++) { |
| 116 | if (boot_cpu_has(noptypes[i].cpuid)) { |
| 117 | noptable = noptypes[i].noptable; |
| 118 | break; |
| 119 | } |
| 120 | } |
| 121 | return noptable; |
| 122 | } |
| 123 | |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 124 | #endif /* CONFIG_X86_64 */ |
| 125 | |
| 126 | extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; |
| 127 | extern struct alt_instr __smp_alt_instructions[], __smp_alt_instructions_end[]; |
| 128 | extern u8 *__smp_locks[], *__smp_locks_end[]; |
| 129 | |
| 130 | extern u8 __smp_alt_begin[], __smp_alt_end[]; |
| 131 | |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 132 | /* Replace instructions with better alternatives for this CPU type. |
| 133 | This runs before SMP is initialized to avoid SMP problems with |
| 134 | self modifying code. This implies that assymetric systems where |
| 135 | APs have less capabilities than the boot processor are not handled. |
| 136 | Tough. Make sure you disable such features by hand. */ |
| 137 | |
| 138 | void apply_alternatives(struct alt_instr *start, struct alt_instr *end) |
| 139 | { |
| 140 | unsigned char **noptable = find_nop_table(); |
| 141 | struct alt_instr *a; |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 142 | u8 *instr; |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 143 | int diff, i, k; |
| 144 | |
| 145 | DPRINTK("%s: alt table %p -> %p\n", __FUNCTION__, start, end); |
| 146 | for (a = start; a < end; a++) { |
| 147 | BUG_ON(a->replacementlen > a->instrlen); |
| 148 | if (!boot_cpu_has(a->cpuid)) |
| 149 | continue; |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 150 | instr = a->instr; |
| 151 | #ifdef CONFIG_X86_64 |
| 152 | /* vsyscall code is not mapped yet. resolve it manually. */ |
| 153 | if (instr >= (u8 *)VSYSCALL_START && instr < (u8*)VSYSCALL_END) { |
| 154 | instr = __va(instr - (u8*)VSYSCALL_START + (u8*)__pa_symbol(&__vsyscall_0)); |
| 155 | DPRINTK("%s: vsyscall fixup: %p => %p\n", |
| 156 | __FUNCTION__, a->instr, instr); |
| 157 | } |
| 158 | #endif |
| 159 | memcpy(instr, a->replacement, a->replacementlen); |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 160 | diff = a->instrlen - a->replacementlen; |
| 161 | /* Pad the rest with nops */ |
| 162 | for (i = a->replacementlen; diff > 0; diff -= k, i += k) { |
| 163 | k = diff; |
| 164 | if (k > ASM_NOP_MAX) |
| 165 | k = ASM_NOP_MAX; |
| 166 | memcpy(a->instr + i, noptable[k], k); |
| 167 | } |
| 168 | } |
| 169 | } |
| 170 | |
| 171 | static void alternatives_smp_save(struct alt_instr *start, struct alt_instr *end) |
| 172 | { |
| 173 | struct alt_instr *a; |
| 174 | |
| 175 | DPRINTK("%s: alt table %p-%p\n", __FUNCTION__, start, end); |
| 176 | for (a = start; a < end; a++) { |
| 177 | memcpy(a->replacement + a->replacementlen, |
| 178 | a->instr, |
| 179 | a->instrlen); |
| 180 | } |
| 181 | } |
| 182 | |
| 183 | static void alternatives_smp_apply(struct alt_instr *start, struct alt_instr *end) |
| 184 | { |
| 185 | struct alt_instr *a; |
| 186 | |
| 187 | for (a = start; a < end; a++) { |
| 188 | memcpy(a->instr, |
| 189 | a->replacement + a->replacementlen, |
| 190 | a->instrlen); |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end) |
| 195 | { |
| 196 | u8 **ptr; |
| 197 | |
| 198 | for (ptr = start; ptr < end; ptr++) { |
| 199 | if (*ptr < text) |
| 200 | continue; |
| 201 | if (*ptr > text_end) |
| 202 | continue; |
| 203 | **ptr = 0xf0; /* lock prefix */ |
| 204 | }; |
| 205 | } |
| 206 | |
| 207 | static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end) |
| 208 | { |
| 209 | unsigned char **noptable = find_nop_table(); |
| 210 | u8 **ptr; |
| 211 | |
| 212 | for (ptr = start; ptr < end; ptr++) { |
| 213 | if (*ptr < text) |
| 214 | continue; |
| 215 | if (*ptr > text_end) |
| 216 | continue; |
| 217 | **ptr = noptable[1][0]; |
| 218 | }; |
| 219 | } |
| 220 | |
| 221 | struct smp_alt_module { |
| 222 | /* what is this ??? */ |
| 223 | struct module *mod; |
| 224 | char *name; |
| 225 | |
| 226 | /* ptrs to lock prefixes */ |
| 227 | u8 **locks; |
| 228 | u8 **locks_end; |
| 229 | |
| 230 | /* .text segment, needed to avoid patching init code ;) */ |
| 231 | u8 *text; |
| 232 | u8 *text_end; |
| 233 | |
| 234 | struct list_head next; |
| 235 | }; |
| 236 | static LIST_HEAD(smp_alt_modules); |
| 237 | static DEFINE_SPINLOCK(smp_alt); |
| 238 | |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 239 | void alternatives_smp_module_add(struct module *mod, char *name, |
| 240 | void *locks, void *locks_end, |
| 241 | void *text, void *text_end) |
| 242 | { |
| 243 | struct smp_alt_module *smp; |
| 244 | unsigned long flags; |
| 245 | |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 246 | if (no_replacement) |
| 247 | return; |
| 248 | |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 249 | if (smp_alt_once) { |
| 250 | if (boot_cpu_has(X86_FEATURE_UP)) |
| 251 | alternatives_smp_unlock(locks, locks_end, |
| 252 | text, text_end); |
| 253 | return; |
| 254 | } |
| 255 | |
| 256 | smp = kzalloc(sizeof(*smp), GFP_KERNEL); |
| 257 | if (NULL == smp) |
| 258 | return; /* we'll run the (safe but slow) SMP code then ... */ |
| 259 | |
| 260 | smp->mod = mod; |
| 261 | smp->name = name; |
| 262 | smp->locks = locks; |
| 263 | smp->locks_end = locks_end; |
| 264 | smp->text = text; |
| 265 | smp->text_end = text_end; |
| 266 | DPRINTK("%s: locks %p -> %p, text %p -> %p, name %s\n", |
| 267 | __FUNCTION__, smp->locks, smp->locks_end, |
| 268 | smp->text, smp->text_end, smp->name); |
| 269 | |
| 270 | spin_lock_irqsave(&smp_alt, flags); |
| 271 | list_add_tail(&smp->next, &smp_alt_modules); |
| 272 | if (boot_cpu_has(X86_FEATURE_UP)) |
| 273 | alternatives_smp_unlock(smp->locks, smp->locks_end, |
| 274 | smp->text, smp->text_end); |
| 275 | spin_unlock_irqrestore(&smp_alt, flags); |
| 276 | } |
| 277 | |
| 278 | void alternatives_smp_module_del(struct module *mod) |
| 279 | { |
| 280 | struct smp_alt_module *item; |
| 281 | unsigned long flags; |
| 282 | |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 283 | if (no_replacement || smp_alt_once) |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 284 | return; |
| 285 | |
| 286 | spin_lock_irqsave(&smp_alt, flags); |
| 287 | list_for_each_entry(item, &smp_alt_modules, next) { |
| 288 | if (mod != item->mod) |
| 289 | continue; |
| 290 | list_del(&item->next); |
| 291 | spin_unlock_irqrestore(&smp_alt, flags); |
| 292 | DPRINTK("%s: %s\n", __FUNCTION__, item->name); |
| 293 | kfree(item); |
| 294 | return; |
| 295 | } |
| 296 | spin_unlock_irqrestore(&smp_alt, flags); |
| 297 | } |
| 298 | |
| 299 | void alternatives_smp_switch(int smp) |
| 300 | { |
| 301 | struct smp_alt_module *mod; |
| 302 | unsigned long flags; |
| 303 | |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 304 | if (no_replacement || smp_alt_once) |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 305 | return; |
| 306 | BUG_ON(!smp && (num_online_cpus() > 1)); |
| 307 | |
| 308 | spin_lock_irqsave(&smp_alt, flags); |
| 309 | if (smp) { |
| 310 | printk(KERN_INFO "SMP alternatives: switching to SMP code\n"); |
| 311 | clear_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability); |
| 312 | clear_bit(X86_FEATURE_UP, cpu_data[0].x86_capability); |
| 313 | alternatives_smp_apply(__smp_alt_instructions, |
| 314 | __smp_alt_instructions_end); |
| 315 | list_for_each_entry(mod, &smp_alt_modules, next) |
| 316 | alternatives_smp_lock(mod->locks, mod->locks_end, |
| 317 | mod->text, mod->text_end); |
| 318 | } else { |
| 319 | printk(KERN_INFO "SMP alternatives: switching to UP code\n"); |
| 320 | set_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability); |
| 321 | set_bit(X86_FEATURE_UP, cpu_data[0].x86_capability); |
| 322 | apply_alternatives(__smp_alt_instructions, |
| 323 | __smp_alt_instructions_end); |
| 324 | list_for_each_entry(mod, &smp_alt_modules, next) |
| 325 | alternatives_smp_unlock(mod->locks, mod->locks_end, |
| 326 | mod->text, mod->text_end); |
| 327 | } |
| 328 | spin_unlock_irqrestore(&smp_alt, flags); |
| 329 | } |
| 330 | |
| 331 | void __init alternative_instructions(void) |
| 332 | { |
Gerd Hoffmann | d167a51 | 2006-06-26 13:56:16 +0200 | [diff] [blame] | 333 | if (no_replacement) { |
| 334 | printk(KERN_INFO "(SMP-)alternatives turned off\n"); |
| 335 | free_init_pages("SMP alternatives", |
| 336 | (unsigned long)__smp_alt_begin, |
| 337 | (unsigned long)__smp_alt_end); |
| 338 | return; |
| 339 | } |
Gerd Hoffmann | 9a0b581 | 2006-03-23 02:59:32 -0800 | [diff] [blame] | 340 | apply_alternatives(__alt_instructions, __alt_instructions_end); |
| 341 | |
| 342 | /* switch to patch-once-at-boottime-only mode and free the |
| 343 | * tables in case we know the number of CPUs will never ever |
| 344 | * change */ |
| 345 | #ifdef CONFIG_HOTPLUG_CPU |
| 346 | if (num_possible_cpus() < 2) |
| 347 | smp_alt_once = 1; |
| 348 | #else |
| 349 | smp_alt_once = 1; |
| 350 | #endif |
| 351 | |
| 352 | if (smp_alt_once) { |
| 353 | if (1 == num_possible_cpus()) { |
| 354 | printk(KERN_INFO "SMP alternatives: switching to UP code\n"); |
| 355 | set_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability); |
| 356 | set_bit(X86_FEATURE_UP, cpu_data[0].x86_capability); |
| 357 | apply_alternatives(__smp_alt_instructions, |
| 358 | __smp_alt_instructions_end); |
| 359 | alternatives_smp_unlock(__smp_locks, __smp_locks_end, |
| 360 | _text, _etext); |
| 361 | } |
| 362 | free_init_pages("SMP alternatives", |
| 363 | (unsigned long)__smp_alt_begin, |
| 364 | (unsigned long)__smp_alt_end); |
| 365 | } else { |
| 366 | alternatives_smp_save(__smp_alt_instructions, |
| 367 | __smp_alt_instructions_end); |
| 368 | alternatives_smp_module_add(NULL, "core kernel", |
| 369 | __smp_locks, __smp_locks_end, |
| 370 | _text, _etext); |
| 371 | alternatives_smp_switch(0); |
| 372 | } |
| 373 | } |