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/processor.h>
  9. #include <asm/i387.h>
  10. #include <asm/msr.h>
  11. #include <asm/io.h>
  12. #include <asm/mmu_context.h>
  13. #include <asm/mtrr.h>
  14. #include <asm/mce.h>
  15. #include <asm/pat.h>
  16. #include <asm/asm.h>
  17. #ifdef CONFIG_X86_LOCAL_APIC
  18. #include <asm/mpspec.h>
  19. #include <asm/apic.h>
  20. #include <mach_apic.h>
  21. #endif
  22. #include "cpu.h"
  23. DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = {
  24. [GDT_ENTRY_KERNEL_CS] = { { { 0x0000ffff, 0x00cf9a00 } } },
  25. [GDT_ENTRY_KERNEL_DS] = { { { 0x0000ffff, 0x00cf9200 } } },
  26. [GDT_ENTRY_DEFAULT_USER_CS] = { { { 0x0000ffff, 0x00cffa00 } } },
  27. [GDT_ENTRY_DEFAULT_USER_DS] = { { { 0x0000ffff, 0x00cff200 } } },
  28. /*
  29. * Segments used for calling PnP BIOS have byte granularity.
  30. * They code segments and data segments have fixed 64k limits,
  31. * the transfer segment sizes are set at run time.
  32. */
  33. /* 32-bit code */
  34. [GDT_ENTRY_PNPBIOS_CS32] = { { { 0x0000ffff, 0x00409a00 } } },
  35. /* 16-bit code */
  36. [GDT_ENTRY_PNPBIOS_CS16] = { { { 0x0000ffff, 0x00009a00 } } },
  37. /* 16-bit data */
  38. [GDT_ENTRY_PNPBIOS_DS] = { { { 0x0000ffff, 0x00009200 } } },
  39. /* 16-bit data */
  40. [GDT_ENTRY_PNPBIOS_TS1] = { { { 0x00000000, 0x00009200 } } },
  41. /* 16-bit data */
  42. [GDT_ENTRY_PNPBIOS_TS2] = { { { 0x00000000, 0x00009200 } } },
  43. /*
  44. * The APM segments have byte granularity and their bases
  45. * are set at run time. All have 64k limits.
  46. */
  47. /* 32-bit code */
  48. [GDT_ENTRY_APMBIOS_BASE] = { { { 0x0000ffff, 0x00409a00 } } },
  49. /* 16-bit code */
  50. [GDT_ENTRY_APMBIOS_BASE+1] = { { { 0x0000ffff, 0x00009a00 } } },
  51. /* data */
  52. [GDT_ENTRY_APMBIOS_BASE+2] = { { { 0x0000ffff, 0x00409200 } } },
  53. [GDT_ENTRY_ESPFIX_SS] = { { { 0x00000000, 0x00c09200 } } },
  54. [GDT_ENTRY_PERCPU] = { { { 0x00000000, 0x00000000 } } },
  55. } };
  56. EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
  57. __u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;
  58. static int cachesize_override __cpuinitdata = -1;
  59. static int disable_x86_serial_nr __cpuinitdata = 1;
  60. struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {};
  61. static void __cpuinit default_init(struct cpuinfo_x86 *c)
  62. {
  63. /* Not much we can do here... */
  64. /* Check if at least it has cpuid */
  65. if (c->cpuid_level == -1) {
  66. /* No cpuid. It must be an ancient CPU */
  67. if (c->x86 == 4)
  68. strcpy(c->x86_model_id, "486");
  69. else if (c->x86 == 3)
  70. strcpy(c->x86_model_id, "386");
  71. }
  72. }
  73. static struct cpu_dev __cpuinitdata default_cpu = {
  74. .c_init = default_init,
  75. .c_vendor = "Unknown",
  76. };
  77. static struct cpu_dev *this_cpu __cpuinitdata = &default_cpu;
  78. static int __init cachesize_setup(char *str)
  79. {
  80. get_option(&str, &cachesize_override);
  81. return 1;
  82. }
  83. __setup("cachesize=", cachesize_setup);
  84. int __cpuinit get_model_name(struct cpuinfo_x86 *c)
  85. {
  86. unsigned int *v;
  87. char *p, *q;
  88. if (cpuid_eax(0x80000000) < 0x80000004)
  89. return 0;
  90. v = (unsigned int *) c->x86_model_id;
  91. cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
  92. cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
  93. cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
  94. c->x86_model_id[48] = 0;
  95. /* Intel chips right-justify this string for some dumb reason;
  96. undo that brain damage */
  97. p = q = &c->x86_model_id[0];
  98. while (*p == ' ')
  99. p++;
  100. if (p != q) {
  101. while (*p)
  102. *q++ = *p++;
  103. while (q <= &c->x86_model_id[48])
  104. *q++ = '\0'; /* Zero-pad the rest */
  105. }
  106. return 1;
  107. }
  108. void __cpuinit display_cacheinfo(struct cpuinfo_x86 *c)
  109. {
  110. unsigned int n, dummy, ecx, edx, l2size;
  111. n = cpuid_eax(0x80000000);
  112. if (n >= 0x80000005) {
  113. cpuid(0x80000005, &dummy, &dummy, &ecx, &edx);
  114. printk(KERN_INFO "CPU: L1 I Cache: %dK (%d bytes/line), D cache %dK (%d bytes/line)\n",
  115. edx>>24, edx&0xFF, ecx>>24, ecx&0xFF);
  116. c->x86_cache_size = (ecx>>24)+(edx>>24);
  117. }
  118. if (n < 0x80000006) /* Some chips just has a large L1. */
  119. return;
  120. ecx = cpuid_ecx(0x80000006);
  121. l2size = ecx >> 16;
  122. /* do processor-specific cache resizing */
  123. if (this_cpu->c_size_cache)
  124. l2size = this_cpu->c_size_cache(c, l2size);
  125. /* Allow user to override all this if necessary. */
  126. if (cachesize_override != -1)
  127. l2size = cachesize_override;
  128. if (l2size == 0)
  129. return; /* Again, no L2 cache is possible */
  130. c->x86_cache_size = l2size;
  131. printk(KERN_INFO "CPU: L2 Cache: %dK (%d bytes/line)\n",
  132. l2size, ecx & 0xFF);
  133. }
  134. /*
  135. * Naming convention should be: <Name> [(<Codename>)]
  136. * This table only is used unless init_<vendor>() below doesn't set it;
  137. * in particular, if CPUID levels 0x80000002..4 are supported, this isn't used
  138. *
  139. */
  140. /* Look up CPU names by table lookup. */
  141. static char __cpuinit *table_lookup_model(struct cpuinfo_x86 *c)
  142. {
  143. struct cpu_model_info *info;
  144. if (c->x86_model >= 16)
  145. return NULL; /* Range check */
  146. if (!this_cpu)
  147. return NULL;
  148. info = this_cpu->c_models;
  149. while (info && info->family) {
  150. if (info->family == c->x86)
  151. return info->model_names[c->x86_model];
  152. info++;
  153. }
  154. return NULL; /* Not found */
  155. }
  156. static void __cpuinit get_cpu_vendor(struct cpuinfo_x86 *c, int early)
  157. {
  158. char *v = c->x86_vendor_id;
  159. int i;
  160. static int printed;
  161. for (i = 0; i < X86_VENDOR_NUM; i++) {
  162. if (cpu_devs[i]) {
  163. if (!strcmp(v, cpu_devs[i]->c_ident[0]) ||
  164. (cpu_devs[i]->c_ident[1] &&
  165. !strcmp(v, cpu_devs[i]->c_ident[1]))) {
  166. c->x86_vendor = i;
  167. if (!early)
  168. this_cpu = cpu_devs[i];
  169. return;
  170. }
  171. }
  172. }
  173. if (!printed) {
  174. printed++;
  175. printk(KERN_ERR "CPU: Vendor unknown, using generic init.\n");
  176. printk(KERN_ERR "CPU: Your system may be unstable.\n");
  177. }
  178. c->x86_vendor = X86_VENDOR_UNKNOWN;
  179. this_cpu = &default_cpu;
  180. }
  181. static int __init x86_fxsr_setup(char *s)
  182. {
  183. setup_clear_cpu_cap(X86_FEATURE_FXSR);
  184. setup_clear_cpu_cap(X86_FEATURE_XMM);
  185. return 1;
  186. }
  187. __setup("nofxsr", x86_fxsr_setup);
  188. static int __init x86_sep_setup(char *s)
  189. {
  190. setup_clear_cpu_cap(X86_FEATURE_SEP);
  191. return 1;
  192. }
  193. __setup("nosep", x86_sep_setup);
  194. /* Standard macro to see if a specific flag is changeable */
  195. static inline int flag_is_changeable_p(u32 flag)
  196. {
  197. u32 f1, f2;
  198. asm("pushfl\n\t"
  199. "pushfl\n\t"
  200. "popl %0\n\t"
  201. "movl %0,%1\n\t"
  202. "xorl %2,%0\n\t"
  203. "pushl %0\n\t"
  204. "popfl\n\t"
  205. "pushfl\n\t"
  206. "popl %0\n\t"
  207. "popfl\n\t"
  208. : "=&r" (f1), "=&r" (f2)
  209. : "ir" (flag));
  210. return ((f1^f2) & flag) != 0;
  211. }
  212. /* Probe for the CPUID instruction */
  213. static int __cpuinit have_cpuid_p(void)
  214. {
  215. return flag_is_changeable_p(X86_EFLAGS_ID);
  216. }
  217. void __init cpu_detect(struct cpuinfo_x86 *c)
  218. {
  219. /* Get vendor name */
  220. cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
  221. (unsigned int *)&c->x86_vendor_id[0],
  222. (unsigned int *)&c->x86_vendor_id[8],
  223. (unsigned int *)&c->x86_vendor_id[4]);
  224. c->x86 = 4;
  225. if (c->cpuid_level >= 0x00000001) {
  226. u32 junk, tfms, cap0, misc;
  227. cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
  228. c->x86 = (tfms >> 8) & 15;
  229. c->x86_model = (tfms >> 4) & 15;
  230. if (c->x86 == 0xf)
  231. c->x86 += (tfms >> 20) & 0xff;
  232. if (c->x86 >= 0x6)
  233. c->x86_model += ((tfms >> 16) & 0xF) << 4;
  234. c->x86_mask = tfms & 15;
  235. if (cap0 & (1<<19)) {
  236. c->x86_cache_alignment = ((misc >> 8) & 0xff) * 8;
  237. c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
  238. }
  239. }
  240. }
  241. static void __cpuinit early_get_cap(struct cpuinfo_x86 *c)
  242. {
  243. u32 tfms, xlvl;
  244. unsigned int ebx;
  245. memset(&c->x86_capability, 0, sizeof c->x86_capability);
  246. if (have_cpuid_p()) {
  247. /* Intel-defined flags: level 0x00000001 */
  248. if (c->cpuid_level >= 0x00000001) {
  249. u32 capability, excap;
  250. cpuid(0x00000001, &tfms, &ebx, &excap, &capability);
  251. c->x86_capability[0] = capability;
  252. c->x86_capability[4] = excap;
  253. }
  254. /* AMD-defined flags: level 0x80000001 */
  255. xlvl = cpuid_eax(0x80000000);
  256. if ((xlvl & 0xffff0000) == 0x80000000) {
  257. if (xlvl >= 0x80000001) {
  258. c->x86_capability[1] = cpuid_edx(0x80000001);
  259. c->x86_capability[6] = cpuid_ecx(0x80000001);
  260. }
  261. }
  262. }
  263. }
  264. /*
  265. * Do minimum CPU detection early.
  266. * Fields really needed: vendor, cpuid_level, family, model, mask,
  267. * cache alignment.
  268. * The others are not touched to avoid unwanted side effects.
  269. *
  270. * WARNING: this function is only called on the BP. Don't add code here
  271. * that is supposed to run on all CPUs.
  272. */
  273. static void __init early_cpu_detect(void)
  274. {
  275. struct cpuinfo_x86 *c = &boot_cpu_data;
  276. c->x86_cache_alignment = 32;
  277. c->x86_clflush_size = 32;
  278. if (!have_cpuid_p())
  279. return;
  280. cpu_detect(c);
  281. get_cpu_vendor(c, 1);
  282. early_get_cap(c);
  283. if (c->x86_vendor != X86_VENDOR_UNKNOWN &&
  284. cpu_devs[c->x86_vendor]->c_early_init)
  285. cpu_devs[c->x86_vendor]->c_early_init(c);
  286. }
  287. /*
  288. * The NOPL instruction is supposed to exist on all CPUs with
  289. * family >= 6; unfortunately, that's not true in practice because
  290. * of early VIA chips and (more importantly) broken virtualizers that
  291. * are not easy to detect. In the latter case it doesn't even *fail*
  292. * reliably, so probing for it doesn't even work. Disable it completely
  293. * unless we can find a reliable way to detect all the broken cases.
  294. */
  295. static void __cpuinit detect_nopl(struct cpuinfo_x86 *c)
  296. {
  297. clear_cpu_cap(c, X86_FEATURE_NOPL);
  298. }
  299. static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
  300. {
  301. u32 tfms, xlvl;
  302. unsigned int ebx;
  303. if (have_cpuid_p()) {
  304. /* Get vendor name */
  305. cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
  306. (unsigned int *)&c->x86_vendor_id[0],
  307. (unsigned int *)&c->x86_vendor_id[8],
  308. (unsigned int *)&c->x86_vendor_id[4]);
  309. get_cpu_vendor(c, 0);
  310. /* Initialize the standard set of capabilities */
  311. /* Note that the vendor-specific code below might override */
  312. /* Intel-defined flags: level 0x00000001 */
  313. if (c->cpuid_level >= 0x00000001) {
  314. u32 capability, excap;
  315. cpuid(0x00000001, &tfms, &ebx, &excap, &capability);
  316. c->x86_capability[0] = capability;
  317. c->x86_capability[4] = excap;
  318. c->x86 = (tfms >> 8) & 15;
  319. c->x86_model = (tfms >> 4) & 15;
  320. if (c->x86 == 0xf)
  321. c->x86 += (tfms >> 20) & 0xff;
  322. if (c->x86 >= 0x6)
  323. c->x86_model += ((tfms >> 16) & 0xF) << 4;
  324. c->x86_mask = tfms & 15;
  325. c->initial_apicid = (ebx >> 24) & 0xFF;
  326. #ifdef CONFIG_X86_HT
  327. c->apicid = phys_pkg_id(c->initial_apicid, 0);
  328. c->phys_proc_id = c->initial_apicid;
  329. #else
  330. c->apicid = c->initial_apicid;
  331. #endif
  332. if (test_cpu_cap(c, X86_FEATURE_CLFLSH))
  333. c->x86_clflush_size = ((ebx >> 8) & 0xff) * 8;
  334. } else {
  335. /* Have CPUID level 0 only - unheard of */
  336. c->x86 = 4;
  337. }
  338. /* AMD-defined flags: level 0x80000001 */
  339. xlvl = cpuid_eax(0x80000000);
  340. if ((xlvl & 0xffff0000) == 0x80000000) {
  341. if (xlvl >= 0x80000001) {
  342. c->x86_capability[1] = cpuid_edx(0x80000001);
  343. c->x86_capability[6] = cpuid_ecx(0x80000001);
  344. }
  345. if (xlvl >= 0x80000004)
  346. get_model_name(c); /* Default name */
  347. }
  348. init_scattered_cpuid_features(c);
  349. detect_nopl(c);
  350. }
  351. }
  352. static void __cpuinit squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
  353. {
  354. if (cpu_has(c, X86_FEATURE_PN) && disable_x86_serial_nr) {
  355. /* Disable processor serial number */
  356. unsigned long lo, hi;
  357. rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
  358. lo |= 0x200000;
  359. wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
  360. printk(KERN_NOTICE "CPU serial number disabled.\n");
  361. clear_cpu_cap(c, X86_FEATURE_PN);
  362. /* Disabling the serial number may affect the cpuid level */
  363. c->cpuid_level = cpuid_eax(0);
  364. }
  365. }
  366. static int __init x86_serial_nr_setup(char *s)
  367. {
  368. disable_x86_serial_nr = 0;
  369. return 1;
  370. }
  371. __setup("serialnumber", x86_serial_nr_setup);
  372. /*
  373. * This does the hard work of actually picking apart the CPU stuff...
  374. */
  375. static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
  376. {
  377. int i;
  378. c->loops_per_jiffy = loops_per_jiffy;
  379. c->x86_cache_size = -1;
  380. c->x86_vendor = X86_VENDOR_UNKNOWN;
  381. c->cpuid_level = -1; /* CPUID not detected */
  382. c->x86_model = c->x86_mask = 0; /* So far unknown... */
  383. c->x86_vendor_id[0] = '\0'; /* Unset */
  384. c->x86_model_id[0] = '\0'; /* Unset */
  385. c->x86_max_cores = 1;
  386. c->x86_clflush_size = 32;
  387. memset(&c->x86_capability, 0, sizeof c->x86_capability);
  388. if (!have_cpuid_p()) {
  389. /*
  390. * First of all, decide if this is a 486 or higher
  391. * It's a 486 if we can modify the AC flag
  392. */
  393. if (flag_is_changeable_p(X86_EFLAGS_AC))
  394. c->x86 = 4;
  395. else
  396. c->x86 = 3;
  397. }
  398. generic_identify(c);
  399. if (this_cpu->c_identify)
  400. this_cpu->c_identify(c);
  401. /*
  402. * Vendor-specific initialization. In this section we
  403. * canonicalize the feature flags, meaning if there are
  404. * features a certain CPU supports which CPUID doesn't
  405. * tell us, CPUID claiming incorrect flags, or other bugs,
  406. * we handle them here.
  407. *
  408. * At the end of this section, c->x86_capability better
  409. * indicate the features this CPU genuinely supports!
  410. */
  411. if (this_cpu->c_init)
  412. this_cpu->c_init(c);
  413. /* Disable the PN if appropriate */
  414. squash_the_stupid_serial_number(c);
  415. /*
  416. * The vendor-specific functions might have changed features. Now
  417. * we do "generic changes."
  418. */
  419. /* If the model name is still unset, do table lookup. */
  420. if (!c->x86_model_id[0]) {
  421. char *p;
  422. p = table_lookup_model(c);
  423. if (p)
  424. strcpy(c->x86_model_id, p);
  425. else
  426. /* Last resort... */
  427. sprintf(c->x86_model_id, "%02x/%02x",
  428. c->x86, c->x86_model);
  429. }
  430. /*
  431. * On SMP, boot_cpu_data holds the common feature set between
  432. * all CPUs; so make sure that we indicate which features are
  433. * common between the CPUs. The first time this routine gets
  434. * executed, c == &boot_cpu_data.
  435. */
  436. if (c != &boot_cpu_data) {
  437. /* AND the already accumulated flags with these */
  438. for (i = 0 ; i < NCAPINTS ; i++)
  439. boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
  440. }
  441. /* Clear all flags overriden by options */
  442. for (i = 0; i < NCAPINTS; i++)
  443. c->x86_capability[i] &= ~cleared_cpu_caps[i];
  444. /* Init Machine Check Exception if available. */
  445. mcheck_init(c);
  446. select_idle_routine(c);
  447. }
  448. void __init identify_boot_cpu(void)
  449. {
  450. identify_cpu(&boot_cpu_data);
  451. sysenter_setup();
  452. enable_sep_cpu();
  453. }
  454. void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
  455. {
  456. BUG_ON(c == &boot_cpu_data);
  457. identify_cpu(c);
  458. enable_sep_cpu();
  459. mtrr_ap_init();
  460. }
  461. #ifdef CONFIG_X86_HT
  462. void __cpuinit detect_ht(struct cpuinfo_x86 *c)
  463. {
  464. u32 eax, ebx, ecx, edx;
  465. int index_msb, core_bits;
  466. cpuid(1, &eax, &ebx, &ecx, &edx);
  467. if (!cpu_has(c, X86_FEATURE_HT) || cpu_has(c, X86_FEATURE_CMP_LEGACY))
  468. return;
  469. smp_num_siblings = (ebx & 0xff0000) >> 16;
  470. if (smp_num_siblings == 1) {
  471. printk(KERN_INFO "CPU: Hyper-Threading is disabled\n");
  472. } else if (smp_num_siblings > 1) {
  473. if (smp_num_siblings > NR_CPUS) {
  474. printk(KERN_WARNING "CPU: Unsupported number of the "
  475. "siblings %d", smp_num_siblings);
  476. smp_num_siblings = 1;
  477. return;
  478. }
  479. index_msb = get_count_order(smp_num_siblings);
  480. c->phys_proc_id = phys_pkg_id(c->initial_apicid, index_msb);
  481. printk(KERN_INFO "CPU: Physical Processor ID: %d\n",
  482. c->phys_proc_id);
  483. smp_num_siblings = smp_num_siblings / c->x86_max_cores;
  484. index_msb = get_count_order(smp_num_siblings) ;
  485. core_bits = get_count_order(c->x86_max_cores);
  486. c->cpu_core_id = phys_pkg_id(c->initial_apicid, index_msb) &
  487. ((1 << core_bits) - 1);
  488. if (c->x86_max_cores > 1)
  489. printk(KERN_INFO "CPU: Processor Core ID: %d\n",
  490. c->cpu_core_id);
  491. }
  492. }
  493. #endif
  494. static __init int setup_noclflush(char *arg)
  495. {
  496. setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
  497. return 1;
  498. }
  499. __setup("noclflush", setup_noclflush);
  500. void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
  501. {
  502. char *vendor = NULL;
  503. if (c->x86_vendor < X86_VENDOR_NUM)
  504. vendor = this_cpu->c_vendor;
  505. else if (c->cpuid_level >= 0)
  506. vendor = c->x86_vendor_id;
  507. if (vendor && strncmp(c->x86_model_id, vendor, strlen(vendor)))
  508. printk("%s ", vendor);
  509. if (!c->x86_model_id[0])
  510. printk("%d86", c->x86);
  511. else
  512. printk("%s", c->x86_model_id);
  513. if (c->x86_mask || c->cpuid_level >= 0)
  514. printk(" stepping %02x\n", c->x86_mask);
  515. else
  516. printk("\n");
  517. }
  518. static __init int setup_disablecpuid(char *arg)
  519. {
  520. int bit;
  521. if (get_option(&arg, &bit) && bit < NCAPINTS*32)
  522. setup_clear_cpu_cap(bit);
  523. else
  524. return 0;
  525. return 1;
  526. }
  527. __setup("clearcpuid=", setup_disablecpuid);
  528. cpumask_t cpu_initialized __cpuinitdata = CPU_MASK_NONE;
  529. void __init early_cpu_init(void)
  530. {
  531. struct cpu_vendor_dev *cvdev;
  532. for (cvdev = __x86cpuvendor_start ;
  533. cvdev < __x86cpuvendor_end ;
  534. cvdev++)
  535. cpu_devs[cvdev->vendor] = cvdev->cpu_dev;
  536. early_cpu_detect();
  537. validate_pat_support(&boot_cpu_data);
  538. }
  539. /* Make sure %fs is initialized properly in idle threads */
  540. struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
  541. {
  542. memset(regs, 0, sizeof(struct pt_regs));
  543. regs->fs = __KERNEL_PERCPU;
  544. return regs;
  545. }
  546. /* Current gdt points %fs at the "master" per-cpu area: after this,
  547. * it's on the real one. */
  548. void switch_to_new_gdt(void)
  549. {
  550. struct desc_ptr gdt_descr;
  551. gdt_descr.address = (long)get_cpu_gdt_table(smp_processor_id());
  552. gdt_descr.size = GDT_SIZE - 1;
  553. load_gdt(&gdt_descr);
  554. asm("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory");
  555. }
  556. /*
  557. * cpu_init() initializes state that is per-CPU. Some data is already
  558. * initialized (naturally) in the bootstrap process, such as the GDT
  559. * and IDT. We reload them nevertheless, this function acts as a
  560. * 'CPU state barrier', nothing should get across.
  561. */
  562. void __cpuinit cpu_init(void)
  563. {
  564. int cpu = smp_processor_id();
  565. struct task_struct *curr = current;
  566. struct tss_struct *t = &per_cpu(init_tss, cpu);
  567. struct thread_struct *thread = &curr->thread;
  568. if (cpu_test_and_set(cpu, cpu_initialized)) {
  569. printk(KERN_WARNING "CPU#%d already initialized!\n", cpu);
  570. for (;;) local_irq_enable();
  571. }
  572. printk(KERN_INFO "Initializing CPU#%d\n", cpu);
  573. if (cpu_has_vme || cpu_has_tsc || cpu_has_de)
  574. clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
  575. load_idt(&idt_descr);
  576. switch_to_new_gdt();
  577. /*
  578. * Set up and load the per-CPU TSS and LDT
  579. */
  580. atomic_inc(&init_mm.mm_count);
  581. curr->active_mm = &init_mm;
  582. if (curr->mm)
  583. BUG();
  584. enter_lazy_tlb(&init_mm, curr);
  585. load_sp0(t, thread);
  586. set_tss_desc(cpu, t);
  587. load_TR_desc();
  588. load_LDT(&init_mm.context);
  589. #ifdef CONFIG_DOUBLEFAULT
  590. /* Set up doublefault TSS pointer in the GDT */
  591. __set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
  592. #endif
  593. /* Clear %gs. */
  594. asm volatile ("mov %0, %%gs" : : "r" (0));
  595. /* Clear all 6 debug registers: */
  596. set_debugreg(0, 0);
  597. set_debugreg(0, 1);
  598. set_debugreg(0, 2);
  599. set_debugreg(0, 3);
  600. set_debugreg(0, 6);
  601. set_debugreg(0, 7);
  602. /*
  603. * Force FPU initialization:
  604. */
  605. current_thread_info()->status = 0;
  606. clear_used_math();
  607. mxcsr_feature_mask_init();
  608. }
  609. #ifdef CONFIG_HOTPLUG_CPU
  610. void __cpuinit cpu_uninit(void)
  611. {
  612. int cpu = raw_smp_processor_id();
  613. cpu_clear(cpu, cpu_initialized);
  614. /* lazy TLB state */
  615. per_cpu(cpu_tlbstate, cpu).state = 0;
  616. per_cpu(cpu_tlbstate, cpu).active_mm = &init_mm;
  617. }
  618. #endif