common.c 18 KB

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  1. #include <linux/init.h>
  2. #include <linux/string.h>
  3. #include <linux/delay.h>
  4. #include <linux/smp.h>
  5. #include <linux/module.h>
  6. #include <linux/percpu.h>
  7. #include <linux/bootmem.h>
  8. #include <asm/semaphore.h>
  9. #include <asm/processor.h>
  10. #include <asm/i387.h>
  11. #include <asm/msr.h>
  12. #include <asm/io.h>
  13. #include <asm/mmu_context.h>
  14. #include <asm/mtrr.h>
  15. #include <asm/mce.h>
  16. #ifdef CONFIG_X86_LOCAL_APIC
  17. #include <asm/mpspec.h>
  18. #include <asm/apic.h>
  19. #include <mach_apic.h>
  20. #endif
  21. #include "cpu.h"
  22. DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = {
  23. [GDT_ENTRY_KERNEL_CS] = { { { 0x0000ffff, 0x00cf9a00 } } },
  24. [GDT_ENTRY_KERNEL_DS] = { { { 0x0000ffff, 0x00cf9200 } } },
  25. [GDT_ENTRY_DEFAULT_USER_CS] = { { { 0x0000ffff, 0x00cffa00 } } },
  26. [GDT_ENTRY_DEFAULT_USER_DS] = { { { 0x0000ffff, 0x00cff200 } } },
  27. /*
  28. * Segments used for calling PnP BIOS have byte granularity.
  29. * They code segments and data segments have fixed 64k limits,
  30. * the transfer segment sizes are set at run time.
  31. */
  32. /* 32-bit code */
  33. [GDT_ENTRY_PNPBIOS_CS32] = { { { 0x0000ffff, 0x00409a00 } } },
  34. /* 16-bit code */
  35. [GDT_ENTRY_PNPBIOS_CS16] = { { { 0x0000ffff, 0x00009a00 } } },
  36. /* 16-bit data */
  37. [GDT_ENTRY_PNPBIOS_DS] = { { { 0x0000ffff, 0x00009200 } } },
  38. /* 16-bit data */
  39. [GDT_ENTRY_PNPBIOS_TS1] = { { { 0x00000000, 0x00009200 } } },
  40. /* 16-bit data */
  41. [GDT_ENTRY_PNPBIOS_TS2] = { { { 0x00000000, 0x00009200 } } },
  42. /*
  43. * The APM segments have byte granularity and their bases
  44. * are set at run time. All have 64k limits.
  45. */
  46. /* 32-bit code */
  47. [GDT_ENTRY_APMBIOS_BASE] = { { { 0x0000ffff, 0x00409a00 } } },
  48. /* 16-bit code */
  49. [GDT_ENTRY_APMBIOS_BASE+1] = { { { 0x0000ffff, 0x00009a00 } } },
  50. /* data */
  51. [GDT_ENTRY_APMBIOS_BASE+2] = { { { 0x0000ffff, 0x00409200 } } },
  52. [GDT_ENTRY_ESPFIX_SS] = { { { 0x00000000, 0x00c09200 } } },
  53. [GDT_ENTRY_PERCPU] = { { { 0x00000000, 0x00000000 } } },
  54. } };
  55. EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
  56. __u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;
  57. static int cachesize_override __cpuinitdata = -1;
  58. static int disable_x86_serial_nr __cpuinitdata = 1;
  59. struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {};
  60. static void __cpuinit default_init(struct cpuinfo_x86 *c)
  61. {
  62. /* Not much we can do here... */
  63. /* Check if at least it has cpuid */
  64. if (c->cpuid_level == -1) {
  65. /* No cpuid. It must be an ancient CPU */
  66. if (c->x86 == 4)
  67. strcpy(c->x86_model_id, "486");
  68. else if (c->x86 == 3)
  69. strcpy(c->x86_model_id, "386");
  70. }
  71. }
  72. static struct cpu_dev __cpuinitdata default_cpu = {
  73. .c_init = default_init,
  74. .c_vendor = "Unknown",
  75. };
  76. static struct cpu_dev *this_cpu __cpuinitdata = &default_cpu;
  77. static int __init cachesize_setup(char *str)
  78. {
  79. get_option(&str, &cachesize_override);
  80. return 1;
  81. }
  82. __setup("cachesize=", cachesize_setup);
  83. int __cpuinit get_model_name(struct cpuinfo_x86 *c)
  84. {
  85. unsigned int *v;
  86. char *p, *q;
  87. if (cpuid_eax(0x80000000) < 0x80000004)
  88. return 0;
  89. v = (unsigned int *) c->x86_model_id;
  90. cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
  91. cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
  92. cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
  93. c->x86_model_id[48] = 0;
  94. /* Intel chips right-justify this string for some dumb reason;
  95. undo that brain damage */
  96. p = q = &c->x86_model_id[0];
  97. while (*p == ' ')
  98. p++;
  99. if (p != q) {
  100. while (*p)
  101. *q++ = *p++;
  102. while (q <= &c->x86_model_id[48])
  103. *q++ = '\0'; /* Zero-pad the rest */
  104. }
  105. return 1;
  106. }
  107. void __cpuinit display_cacheinfo(struct cpuinfo_x86 *c)
  108. {
  109. unsigned int n, dummy, ecx, edx, l2size;
  110. n = cpuid_eax(0x80000000);
  111. if (n >= 0x80000005) {
  112. cpuid(0x80000005, &dummy, &dummy, &ecx, &edx);
  113. printk(KERN_INFO "CPU: L1 I Cache: %dK (%d bytes/line), D cache %dK (%d bytes/line)\n",
  114. edx>>24, edx&0xFF, ecx>>24, ecx&0xFF);
  115. c->x86_cache_size = (ecx>>24)+(edx>>24);
  116. }
  117. if (n < 0x80000006) /* Some chips just has a large L1. */
  118. return;
  119. ecx = cpuid_ecx(0x80000006);
  120. l2size = ecx >> 16;
  121. /* do processor-specific cache resizing */
  122. if (this_cpu->c_size_cache)
  123. l2size = this_cpu->c_size_cache(c, l2size);
  124. /* Allow user to override all this if necessary. */
  125. if (cachesize_override != -1)
  126. l2size = cachesize_override;
  127. if (l2size == 0)
  128. return; /* Again, no L2 cache is possible */
  129. c->x86_cache_size = l2size;
  130. printk(KERN_INFO "CPU: L2 Cache: %dK (%d bytes/line)\n",
  131. l2size, ecx & 0xFF);
  132. }
  133. /*
  134. * Naming convention should be: <Name> [(<Codename>)]
  135. * This table only is used unless init_<vendor>() below doesn't set it;
  136. * in particular, if CPUID levels 0x80000002..4 are supported, this isn't used
  137. *
  138. */
  139. /* Look up CPU names by table lookup. */
  140. static char __cpuinit *table_lookup_model(struct cpuinfo_x86 *c)
  141. {
  142. struct cpu_model_info *info;
  143. if (c->x86_model >= 16)
  144. return NULL; /* Range check */
  145. if (!this_cpu)
  146. return NULL;
  147. info = this_cpu->c_models;
  148. while (info && info->family) {
  149. if (info->family == c->x86)
  150. return info->model_names[c->x86_model];
  151. info++;
  152. }
  153. return NULL; /* Not found */
  154. }
  155. static void __cpuinit get_cpu_vendor(struct cpuinfo_x86 *c, int early)
  156. {
  157. char *v = c->x86_vendor_id;
  158. int i;
  159. static int printed;
  160. for (i = 0; i < X86_VENDOR_NUM; i++) {
  161. if (cpu_devs[i]) {
  162. if (!strcmp(v, cpu_devs[i]->c_ident[0]) ||
  163. (cpu_devs[i]->c_ident[1] &&
  164. !strcmp(v, cpu_devs[i]->c_ident[1]))) {
  165. c->x86_vendor = i;
  166. if (!early)
  167. this_cpu = cpu_devs[i];
  168. return;
  169. }
  170. }
  171. }
  172. if (!printed) {
  173. printed++;
  174. printk(KERN_ERR "CPU: Vendor unknown, using generic init.\n");
  175. printk(KERN_ERR "CPU: Your system may be unstable.\n");
  176. }
  177. c->x86_vendor = X86_VENDOR_UNKNOWN;
  178. this_cpu = &default_cpu;
  179. }
  180. static int __init x86_fxsr_setup(char *s)
  181. {
  182. setup_clear_cpu_cap(X86_FEATURE_FXSR);
  183. setup_clear_cpu_cap(X86_FEATURE_XMM);
  184. return 1;
  185. }
  186. __setup("nofxsr", x86_fxsr_setup);
  187. static int __init x86_sep_setup(char *s)
  188. {
  189. setup_clear_cpu_cap(X86_FEATURE_SEP);
  190. return 1;
  191. }
  192. __setup("nosep", x86_sep_setup);
  193. /* Standard macro to see if a specific flag is changeable */
  194. static inline int flag_is_changeable_p(u32 flag)
  195. {
  196. u32 f1, f2;
  197. asm("pushfl\n\t"
  198. "pushfl\n\t"
  199. "popl %0\n\t"
  200. "movl %0,%1\n\t"
  201. "xorl %2,%0\n\t"
  202. "pushl %0\n\t"
  203. "popfl\n\t"
  204. "pushfl\n\t"
  205. "popl %0\n\t"
  206. "popfl\n\t"
  207. : "=&r" (f1), "=&r" (f2)
  208. : "ir" (flag));
  209. return ((f1^f2) & flag) != 0;
  210. }
  211. /* Probe for the CPUID instruction */
  212. static int __cpuinit have_cpuid_p(void)
  213. {
  214. return flag_is_changeable_p(X86_EFLAGS_ID);
  215. }
  216. void __init cpu_detect(struct cpuinfo_x86 *c)
  217. {
  218. /* Get vendor name */
  219. cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
  220. (unsigned int *)&c->x86_vendor_id[0],
  221. (unsigned int *)&c->x86_vendor_id[8],
  222. (unsigned int *)&c->x86_vendor_id[4]);
  223. c->x86 = 4;
  224. if (c->cpuid_level >= 0x00000001) {
  225. u32 junk, tfms, cap0, misc;
  226. cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
  227. c->x86 = (tfms >> 8) & 15;
  228. c->x86_model = (tfms >> 4) & 15;
  229. if (c->x86 == 0xf)
  230. c->x86 += (tfms >> 20) & 0xff;
  231. if (c->x86 >= 0x6)
  232. c->x86_model += ((tfms >> 16) & 0xF) << 4;
  233. c->x86_mask = tfms & 15;
  234. if (cap0 & (1<<19)) {
  235. c->x86_cache_alignment = ((misc >> 8) & 0xff) * 8;
  236. c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
  237. }
  238. }
  239. }
  240. static void __cpuinit early_get_cap(struct cpuinfo_x86 *c)
  241. {
  242. u32 tfms, xlvl;
  243. unsigned int ebx;
  244. memset(&c->x86_capability, 0, sizeof c->x86_capability);
  245. if (have_cpuid_p()) {
  246. /* Intel-defined flags: level 0x00000001 */
  247. if (c->cpuid_level >= 0x00000001) {
  248. u32 capability, excap;
  249. cpuid(0x00000001, &tfms, &ebx, &excap, &capability);
  250. c->x86_capability[0] = capability;
  251. c->x86_capability[4] = excap;
  252. }
  253. /* AMD-defined flags: level 0x80000001 */
  254. xlvl = cpuid_eax(0x80000000);
  255. if ((xlvl & 0xffff0000) == 0x80000000) {
  256. if (xlvl >= 0x80000001) {
  257. c->x86_capability[1] = cpuid_edx(0x80000001);
  258. c->x86_capability[6] = cpuid_ecx(0x80000001);
  259. }
  260. }
  261. }
  262. }
  263. /*
  264. * Do minimum CPU detection early.
  265. * Fields really needed: vendor, cpuid_level, family, model, mask,
  266. * cache alignment.
  267. * The others are not touched to avoid unwanted side effects.
  268. *
  269. * WARNING: this function is only called on the BP. Don't add code here
  270. * that is supposed to run on all CPUs.
  271. */
  272. static void __init early_cpu_detect(void)
  273. {
  274. struct cpuinfo_x86 *c = &boot_cpu_data;
  275. c->x86_cache_alignment = 32;
  276. c->x86_clflush_size = 32;
  277. if (!have_cpuid_p())
  278. return;
  279. cpu_detect(c);
  280. get_cpu_vendor(c, 1);
  281. if (c->x86_vendor != X86_VENDOR_UNKNOWN &&
  282. cpu_devs[c->x86_vendor]->c_early_init)
  283. cpu_devs[c->x86_vendor]->c_early_init(c);
  284. early_get_cap(c);
  285. }
  286. static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
  287. {
  288. u32 tfms, xlvl;
  289. unsigned int ebx;
  290. if (have_cpuid_p()) {
  291. /* Get vendor name */
  292. cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
  293. (unsigned int *)&c->x86_vendor_id[0],
  294. (unsigned int *)&c->x86_vendor_id[8],
  295. (unsigned int *)&c->x86_vendor_id[4]);
  296. get_cpu_vendor(c, 0);
  297. /* Initialize the standard set of capabilities */
  298. /* Note that the vendor-specific code below might override */
  299. /* Intel-defined flags: level 0x00000001 */
  300. if (c->cpuid_level >= 0x00000001) {
  301. u32 capability, excap;
  302. cpuid(0x00000001, &tfms, &ebx, &excap, &capability);
  303. c->x86_capability[0] = capability;
  304. c->x86_capability[4] = excap;
  305. c->x86 = (tfms >> 8) & 15;
  306. c->x86_model = (tfms >> 4) & 15;
  307. if (c->x86 == 0xf)
  308. c->x86 += (tfms >> 20) & 0xff;
  309. if (c->x86 >= 0x6)
  310. c->x86_model += ((tfms >> 16) & 0xF) << 4;
  311. c->x86_mask = tfms & 15;
  312. #ifdef CONFIG_X86_HT
  313. c->apicid = phys_pkg_id((ebx >> 24) & 0xFF, 0);
  314. #else
  315. c->apicid = (ebx >> 24) & 0xFF;
  316. #endif
  317. if (test_cpu_cap(c, X86_FEATURE_CLFLSH))
  318. c->x86_clflush_size = ((ebx >> 8) & 0xff) * 8;
  319. } else {
  320. /* Have CPUID level 0 only - unheard of */
  321. c->x86 = 4;
  322. }
  323. /* AMD-defined flags: level 0x80000001 */
  324. xlvl = cpuid_eax(0x80000000);
  325. if ((xlvl & 0xffff0000) == 0x80000000) {
  326. if (xlvl >= 0x80000001) {
  327. c->x86_capability[1] = cpuid_edx(0x80000001);
  328. c->x86_capability[6] = cpuid_ecx(0x80000001);
  329. }
  330. if (xlvl >= 0x80000004)
  331. get_model_name(c); /* Default name */
  332. }
  333. init_scattered_cpuid_features(c);
  334. }
  335. #ifdef CONFIG_X86_HT
  336. c->phys_proc_id = (cpuid_ebx(1) >> 24) & 0xff;
  337. #endif
  338. }
  339. static void __cpuinit squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
  340. {
  341. if (cpu_has(c, X86_FEATURE_PN) && disable_x86_serial_nr) {
  342. /* Disable processor serial number */
  343. unsigned long lo, hi;
  344. rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
  345. lo |= 0x200000;
  346. wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
  347. printk(KERN_NOTICE "CPU serial number disabled.\n");
  348. clear_cpu_cap(c, X86_FEATURE_PN);
  349. /* Disabling the serial number may affect the cpuid level */
  350. c->cpuid_level = cpuid_eax(0);
  351. }
  352. }
  353. static int __init x86_serial_nr_setup(char *s)
  354. {
  355. disable_x86_serial_nr = 0;
  356. return 1;
  357. }
  358. __setup("serialnumber", x86_serial_nr_setup);
  359. /*
  360. * This does the hard work of actually picking apart the CPU stuff...
  361. */
  362. void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
  363. {
  364. int i;
  365. c->loops_per_jiffy = loops_per_jiffy;
  366. c->x86_cache_size = -1;
  367. c->x86_vendor = X86_VENDOR_UNKNOWN;
  368. c->cpuid_level = -1; /* CPUID not detected */
  369. c->x86_model = c->x86_mask = 0; /* So far unknown... */
  370. c->x86_vendor_id[0] = '\0'; /* Unset */
  371. c->x86_model_id[0] = '\0'; /* Unset */
  372. c->x86_max_cores = 1;
  373. c->x86_clflush_size = 32;
  374. memset(&c->x86_capability, 0, sizeof c->x86_capability);
  375. if (!have_cpuid_p()) {
  376. /*
  377. * First of all, decide if this is a 486 or higher
  378. * It's a 486 if we can modify the AC flag
  379. */
  380. if (flag_is_changeable_p(X86_EFLAGS_AC))
  381. c->x86 = 4;
  382. else
  383. c->x86 = 3;
  384. }
  385. generic_identify(c);
  386. if (this_cpu->c_identify)
  387. this_cpu->c_identify(c);
  388. /*
  389. * Vendor-specific initialization. In this section we
  390. * canonicalize the feature flags, meaning if there are
  391. * features a certain CPU supports which CPUID doesn't
  392. * tell us, CPUID claiming incorrect flags, or other bugs,
  393. * we handle them here.
  394. *
  395. * At the end of this section, c->x86_capability better
  396. * indicate the features this CPU genuinely supports!
  397. */
  398. if (this_cpu->c_init)
  399. this_cpu->c_init(c);
  400. /* Disable the PN if appropriate */
  401. squash_the_stupid_serial_number(c);
  402. /*
  403. * The vendor-specific functions might have changed features. Now
  404. * we do "generic changes."
  405. */
  406. /* If the model name is still unset, do table lookup. */
  407. if (!c->x86_model_id[0]) {
  408. char *p;
  409. p = table_lookup_model(c);
  410. if (p)
  411. strcpy(c->x86_model_id, p);
  412. else
  413. /* Last resort... */
  414. sprintf(c->x86_model_id, "%02x/%02x",
  415. c->x86, c->x86_model);
  416. }
  417. /*
  418. * On SMP, boot_cpu_data holds the common feature set between
  419. * all CPUs; so make sure that we indicate which features are
  420. * common between the CPUs. The first time this routine gets
  421. * executed, c == &boot_cpu_data.
  422. */
  423. if (c != &boot_cpu_data) {
  424. /* AND the already accumulated flags with these */
  425. for (i = 0 ; i < NCAPINTS ; i++)
  426. boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
  427. }
  428. /* Clear all flags overriden by options */
  429. for (i = 0; i < NCAPINTS; i++)
  430. c->x86_capability[i] &= ~cleared_cpu_caps[i];
  431. /* Init Machine Check Exception if available. */
  432. mcheck_init(c);
  433. select_idle_routine(c);
  434. }
  435. void __init identify_boot_cpu(void)
  436. {
  437. identify_cpu(&boot_cpu_data);
  438. sysenter_setup();
  439. enable_sep_cpu();
  440. }
  441. void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
  442. {
  443. BUG_ON(c == &boot_cpu_data);
  444. identify_cpu(c);
  445. enable_sep_cpu();
  446. mtrr_ap_init();
  447. }
  448. #ifdef CONFIG_X86_HT
  449. void __cpuinit detect_ht(struct cpuinfo_x86 *c)
  450. {
  451. u32 eax, ebx, ecx, edx;
  452. int index_msb, core_bits;
  453. cpuid(1, &eax, &ebx, &ecx, &edx);
  454. if (!cpu_has(c, X86_FEATURE_HT) || cpu_has(c, X86_FEATURE_CMP_LEGACY))
  455. return;
  456. smp_num_siblings = (ebx & 0xff0000) >> 16;
  457. if (smp_num_siblings == 1) {
  458. printk(KERN_INFO "CPU: Hyper-Threading is disabled\n");
  459. } else if (smp_num_siblings > 1) {
  460. if (smp_num_siblings > NR_CPUS) {
  461. printk(KERN_WARNING "CPU: Unsupported number of the "
  462. "siblings %d", smp_num_siblings);
  463. smp_num_siblings = 1;
  464. return;
  465. }
  466. index_msb = get_count_order(smp_num_siblings);
  467. c->phys_proc_id = phys_pkg_id((ebx >> 24) & 0xFF, index_msb);
  468. printk(KERN_INFO "CPU: Physical Processor ID: %d\n",
  469. c->phys_proc_id);
  470. smp_num_siblings = smp_num_siblings / c->x86_max_cores;
  471. index_msb = get_count_order(smp_num_siblings) ;
  472. core_bits = get_count_order(c->x86_max_cores);
  473. c->cpu_core_id = phys_pkg_id((ebx >> 24) & 0xFF, index_msb) &
  474. ((1 << core_bits) - 1);
  475. if (c->x86_max_cores > 1)
  476. printk(KERN_INFO "CPU: Processor Core ID: %d\n",
  477. c->cpu_core_id);
  478. }
  479. }
  480. #endif
  481. static __init int setup_noclflush(char *arg)
  482. {
  483. setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
  484. return 1;
  485. }
  486. __setup("noclflush", setup_noclflush);
  487. void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
  488. {
  489. char *vendor = NULL;
  490. if (c->x86_vendor < X86_VENDOR_NUM)
  491. vendor = this_cpu->c_vendor;
  492. else if (c->cpuid_level >= 0)
  493. vendor = c->x86_vendor_id;
  494. if (vendor && strncmp(c->x86_model_id, vendor, strlen(vendor)))
  495. printk("%s ", vendor);
  496. if (!c->x86_model_id[0])
  497. printk("%d86", c->x86);
  498. else
  499. printk("%s", c->x86_model_id);
  500. if (c->x86_mask || c->cpuid_level >= 0)
  501. printk(" stepping %02x\n", c->x86_mask);
  502. else
  503. printk("\n");
  504. }
  505. static __init int setup_disablecpuid(char *arg)
  506. {
  507. int bit;
  508. if (get_option(&arg, &bit) && bit < NCAPINTS*32)
  509. setup_clear_cpu_cap(bit);
  510. else
  511. return 0;
  512. return 1;
  513. }
  514. __setup("clearcpuid=", setup_disablecpuid);
  515. cpumask_t cpu_initialized __cpuinitdata = CPU_MASK_NONE;
  516. void __init early_cpu_init(void)
  517. {
  518. struct cpu_vendor_dev *cvdev;
  519. for (cvdev = __x86cpuvendor_start ;
  520. cvdev < __x86cpuvendor_end ;
  521. cvdev++)
  522. cpu_devs[cvdev->vendor] = cvdev->cpu_dev;
  523. early_cpu_detect();
  524. }
  525. /* Make sure %fs is initialized properly in idle threads */
  526. struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
  527. {
  528. memset(regs, 0, sizeof(struct pt_regs));
  529. regs->fs = __KERNEL_PERCPU;
  530. return regs;
  531. }
  532. /* Current gdt points %fs at the "master" per-cpu area: after this,
  533. * it's on the real one. */
  534. void switch_to_new_gdt(void)
  535. {
  536. struct desc_ptr gdt_descr;
  537. gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());
  538. gdt_descr.size = GDT_SIZE - 1;
  539. load_gdt(&gdt_descr);
  540. asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory");
  541. }
  542. /*
  543. * cpu_init() initializes state that is per-CPU. Some data is already
  544. * initialized (naturally) in the bootstrap process, such as the GDT
  545. * and IDT. We reload them nevertheless, this function acts as a
  546. * 'CPU state barrier', nothing should get across.
  547. */
  548. void __cpuinit cpu_init(void)
  549. {
  550. int cpu = smp_processor_id();
  551. struct task_struct *curr = current;
  552. struct tss_struct *t = &per_cpu(init_tss, cpu);
  553. struct thread_struct *thread = &curr->thread;
  554. if (cpu_test_and_set(cpu, cpu_initialized)) {
  555. printk(KERN_WARNING "CPU#%d already initialized!\n", cpu);
  556. for (;;) local_irq_enable();
  557. }
  558. printk(KERN_INFO "Initializing CPU#%d\n", cpu);
  559. if (cpu_has_vme || cpu_has_tsc || cpu_has_de)
  560. clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
  561. load_idt(&idt_descr);
  562. switch_to_new_gdt();
  563. /*
  564. * Set up and load the per-CPU TSS and LDT
  565. */
  566. atomic_inc(&init_mm.mm_count);
  567. curr->active_mm = &init_mm;
  568. if (curr->mm)
  569. BUG();
  570. enter_lazy_tlb(&init_mm, curr);
  571. load_sp0(t, thread);
  572. set_tss_desc(cpu, t);
  573. load_TR_desc();
  574. load_LDT(&init_mm.context);
  575. #ifdef CONFIG_DOUBLEFAULT
  576. /* Set up doublefault TSS pointer in the GDT */
  577. __set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
  578. #endif
  579. /* Clear %gs. */
  580. asm volatile ("mov %0, %%gs" : : "r" (0));
  581. /* Clear all 6 debug registers: */
  582. set_debugreg(0, 0);
  583. set_debugreg(0, 1);
  584. set_debugreg(0, 2);
  585. set_debugreg(0, 3);
  586. set_debugreg(0, 6);
  587. set_debugreg(0, 7);
  588. /*
  589. * Force FPU initialization:
  590. */
  591. current_thread_info()->status = 0;
  592. clear_used_math();
  593. mxcsr_feature_mask_init();
  594. }
  595. #ifdef CONFIG_HOTPLUG_CPU
  596. void __cpuinit cpu_uninit(void)
  597. {
  598. int cpu = raw_smp_processor_id();
  599. cpu_clear(cpu, cpu_initialized);
  600. /* lazy TLB state */
  601. per_cpu(cpu_tlbstate, cpu).state = 0;
  602. per_cpu(cpu_tlbstate, cpu).active_mm = &init_mm;
  603. }
  604. #endif