xref: /linux/arch/x86/kernel/cpu/common.c (revision 9ffc93f203c18a70623f21950f1dd473c9ec48cd)
1 #include <linux/bootmem.h>
2 #include <linux/linkage.h>
3 #include <linux/bitops.h>
4 #include <linux/kernel.h>
5 #include <linux/module.h>
6 #include <linux/percpu.h>
7 #include <linux/string.h>
8 #include <linux/delay.h>
9 #include <linux/sched.h>
10 #include <linux/init.h>
11 #include <linux/kgdb.h>
12 #include <linux/smp.h>
13 #include <linux/io.h>
14 
15 #include <asm/stackprotector.h>
16 #include <asm/perf_event.h>
17 #include <asm/mmu_context.h>
18 #include <asm/archrandom.h>
19 #include <asm/hypervisor.h>
20 #include <asm/processor.h>
21 #include <asm/sections.h>
22 #include <linux/topology.h>
23 #include <linux/cpumask.h>
24 #include <asm/pgtable.h>
25 #include <linux/atomic.h>
26 #include <asm/proto.h>
27 #include <asm/setup.h>
28 #include <asm/apic.h>
29 #include <asm/desc.h>
30 #include <asm/i387.h>
31 #include <asm/fpu-internal.h>
32 #include <asm/mtrr.h>
33 #include <linux/numa.h>
34 #include <asm/asm.h>
35 #include <asm/cpu.h>
36 #include <asm/mce.h>
37 #include <asm/msr.h>
38 #include <asm/pat.h>
39 
40 #ifdef CONFIG_X86_LOCAL_APIC
41 #include <asm/uv/uv.h>
42 #endif
43 
44 #include "cpu.h"
45 
46 /* all of these masks are initialized in setup_cpu_local_masks() */
47 cpumask_var_t cpu_initialized_mask;
48 cpumask_var_t cpu_callout_mask;
49 cpumask_var_t cpu_callin_mask;
50 
51 /* representing cpus for which sibling maps can be computed */
52 cpumask_var_t cpu_sibling_setup_mask;
53 
54 /* correctly size the local cpu masks */
55 void __init setup_cpu_local_masks(void)
56 {
57 	alloc_bootmem_cpumask_var(&cpu_initialized_mask);
58 	alloc_bootmem_cpumask_var(&cpu_callin_mask);
59 	alloc_bootmem_cpumask_var(&cpu_callout_mask);
60 	alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask);
61 }
62 
63 static void __cpuinit default_init(struct cpuinfo_x86 *c)
64 {
65 #ifdef CONFIG_X86_64
66 	cpu_detect_cache_sizes(c);
67 #else
68 	/* Not much we can do here... */
69 	/* Check if at least it has cpuid */
70 	if (c->cpuid_level == -1) {
71 		/* No cpuid. It must be an ancient CPU */
72 		if (c->x86 == 4)
73 			strcpy(c->x86_model_id, "486");
74 		else if (c->x86 == 3)
75 			strcpy(c->x86_model_id, "386");
76 	}
77 #endif
78 }
79 
80 static const struct cpu_dev __cpuinitconst default_cpu = {
81 	.c_init		= default_init,
82 	.c_vendor	= "Unknown",
83 	.c_x86_vendor	= X86_VENDOR_UNKNOWN,
84 };
85 
86 static const struct cpu_dev *this_cpu __cpuinitdata = &default_cpu;
87 
88 DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = {
89 #ifdef CONFIG_X86_64
90 	/*
91 	 * We need valid kernel segments for data and code in long mode too
92 	 * IRET will check the segment types  kkeil 2000/10/28
93 	 * Also sysret mandates a special GDT layout
94 	 *
95 	 * TLS descriptors are currently at a different place compared to i386.
96 	 * Hopefully nobody expects them at a fixed place (Wine?)
97 	 */
98 	[GDT_ENTRY_KERNEL32_CS]		= GDT_ENTRY_INIT(0xc09b, 0, 0xfffff),
99 	[GDT_ENTRY_KERNEL_CS]		= GDT_ENTRY_INIT(0xa09b, 0, 0xfffff),
100 	[GDT_ENTRY_KERNEL_DS]		= GDT_ENTRY_INIT(0xc093, 0, 0xfffff),
101 	[GDT_ENTRY_DEFAULT_USER32_CS]	= GDT_ENTRY_INIT(0xc0fb, 0, 0xfffff),
102 	[GDT_ENTRY_DEFAULT_USER_DS]	= GDT_ENTRY_INIT(0xc0f3, 0, 0xfffff),
103 	[GDT_ENTRY_DEFAULT_USER_CS]	= GDT_ENTRY_INIT(0xa0fb, 0, 0xfffff),
104 #else
105 	[GDT_ENTRY_KERNEL_CS]		= GDT_ENTRY_INIT(0xc09a, 0, 0xfffff),
106 	[GDT_ENTRY_KERNEL_DS]		= GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
107 	[GDT_ENTRY_DEFAULT_USER_CS]	= GDT_ENTRY_INIT(0xc0fa, 0, 0xfffff),
108 	[GDT_ENTRY_DEFAULT_USER_DS]	= GDT_ENTRY_INIT(0xc0f2, 0, 0xfffff),
109 	/*
110 	 * Segments used for calling PnP BIOS have byte granularity.
111 	 * They code segments and data segments have fixed 64k limits,
112 	 * the transfer segment sizes are set at run time.
113 	 */
114 	/* 32-bit code */
115 	[GDT_ENTRY_PNPBIOS_CS32]	= GDT_ENTRY_INIT(0x409a, 0, 0xffff),
116 	/* 16-bit code */
117 	[GDT_ENTRY_PNPBIOS_CS16]	= GDT_ENTRY_INIT(0x009a, 0, 0xffff),
118 	/* 16-bit data */
119 	[GDT_ENTRY_PNPBIOS_DS]		= GDT_ENTRY_INIT(0x0092, 0, 0xffff),
120 	/* 16-bit data */
121 	[GDT_ENTRY_PNPBIOS_TS1]		= GDT_ENTRY_INIT(0x0092, 0, 0),
122 	/* 16-bit data */
123 	[GDT_ENTRY_PNPBIOS_TS2]		= GDT_ENTRY_INIT(0x0092, 0, 0),
124 	/*
125 	 * The APM segments have byte granularity and their bases
126 	 * are set at run time.  All have 64k limits.
127 	 */
128 	/* 32-bit code */
129 	[GDT_ENTRY_APMBIOS_BASE]	= GDT_ENTRY_INIT(0x409a, 0, 0xffff),
130 	/* 16-bit code */
131 	[GDT_ENTRY_APMBIOS_BASE+1]	= GDT_ENTRY_INIT(0x009a, 0, 0xffff),
132 	/* data */
133 	[GDT_ENTRY_APMBIOS_BASE+2]	= GDT_ENTRY_INIT(0x4092, 0, 0xffff),
134 
135 	[GDT_ENTRY_ESPFIX_SS]		= GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
136 	[GDT_ENTRY_PERCPU]		= GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
137 	GDT_STACK_CANARY_INIT
138 #endif
139 } };
140 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
141 
142 static int __init x86_xsave_setup(char *s)
143 {
144 	setup_clear_cpu_cap(X86_FEATURE_XSAVE);
145 	setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
146 	return 1;
147 }
148 __setup("noxsave", x86_xsave_setup);
149 
150 static int __init x86_xsaveopt_setup(char *s)
151 {
152 	setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
153 	return 1;
154 }
155 __setup("noxsaveopt", x86_xsaveopt_setup);
156 
157 #ifdef CONFIG_X86_32
158 static int cachesize_override __cpuinitdata = -1;
159 static int disable_x86_serial_nr __cpuinitdata = 1;
160 
161 static int __init cachesize_setup(char *str)
162 {
163 	get_option(&str, &cachesize_override);
164 	return 1;
165 }
166 __setup("cachesize=", cachesize_setup);
167 
168 static int __init x86_fxsr_setup(char *s)
169 {
170 	setup_clear_cpu_cap(X86_FEATURE_FXSR);
171 	setup_clear_cpu_cap(X86_FEATURE_XMM);
172 	return 1;
173 }
174 __setup("nofxsr", x86_fxsr_setup);
175 
176 static int __init x86_sep_setup(char *s)
177 {
178 	setup_clear_cpu_cap(X86_FEATURE_SEP);
179 	return 1;
180 }
181 __setup("nosep", x86_sep_setup);
182 
183 /* Standard macro to see if a specific flag is changeable */
184 static inline int flag_is_changeable_p(u32 flag)
185 {
186 	u32 f1, f2;
187 
188 	/*
189 	 * Cyrix and IDT cpus allow disabling of CPUID
190 	 * so the code below may return different results
191 	 * when it is executed before and after enabling
192 	 * the CPUID. Add "volatile" to not allow gcc to
193 	 * optimize the subsequent calls to this function.
194 	 */
195 	asm volatile ("pushfl		\n\t"
196 		      "pushfl		\n\t"
197 		      "popl %0		\n\t"
198 		      "movl %0, %1	\n\t"
199 		      "xorl %2, %0	\n\t"
200 		      "pushl %0		\n\t"
201 		      "popfl		\n\t"
202 		      "pushfl		\n\t"
203 		      "popl %0		\n\t"
204 		      "popfl		\n\t"
205 
206 		      : "=&r" (f1), "=&r" (f2)
207 		      : "ir" (flag));
208 
209 	return ((f1^f2) & flag) != 0;
210 }
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 
218 static void __cpuinit squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
219 {
220 	unsigned long lo, hi;
221 
222 	if (!cpu_has(c, X86_FEATURE_PN) || !disable_x86_serial_nr)
223 		return;
224 
225 	/* Disable processor serial number: */
226 
227 	rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
228 	lo |= 0x200000;
229 	wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
230 
231 	printk(KERN_NOTICE "CPU serial number disabled.\n");
232 	clear_cpu_cap(c, X86_FEATURE_PN);
233 
234 	/* Disabling the serial number may affect the cpuid level */
235 	c->cpuid_level = cpuid_eax(0);
236 }
237 
238 static int __init x86_serial_nr_setup(char *s)
239 {
240 	disable_x86_serial_nr = 0;
241 	return 1;
242 }
243 __setup("serialnumber", x86_serial_nr_setup);
244 #else
245 static inline int flag_is_changeable_p(u32 flag)
246 {
247 	return 1;
248 }
249 /* Probe for the CPUID instruction */
250 static inline int have_cpuid_p(void)
251 {
252 	return 1;
253 }
254 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
255 {
256 }
257 #endif
258 
259 static int disable_smep __cpuinitdata;
260 static __init int setup_disable_smep(char *arg)
261 {
262 	disable_smep = 1;
263 	return 1;
264 }
265 __setup("nosmep", setup_disable_smep);
266 
267 static __cpuinit void setup_smep(struct cpuinfo_x86 *c)
268 {
269 	if (cpu_has(c, X86_FEATURE_SMEP)) {
270 		if (unlikely(disable_smep)) {
271 			setup_clear_cpu_cap(X86_FEATURE_SMEP);
272 			clear_in_cr4(X86_CR4_SMEP);
273 		} else
274 			set_in_cr4(X86_CR4_SMEP);
275 	}
276 }
277 
278 /*
279  * Some CPU features depend on higher CPUID levels, which may not always
280  * be available due to CPUID level capping or broken virtualization
281  * software.  Add those features to this table to auto-disable them.
282  */
283 struct cpuid_dependent_feature {
284 	u32 feature;
285 	u32 level;
286 };
287 
288 static const struct cpuid_dependent_feature __cpuinitconst
289 cpuid_dependent_features[] = {
290 	{ X86_FEATURE_MWAIT,		0x00000005 },
291 	{ X86_FEATURE_DCA,		0x00000009 },
292 	{ X86_FEATURE_XSAVE,		0x0000000d },
293 	{ 0, 0 }
294 };
295 
296 static void __cpuinit filter_cpuid_features(struct cpuinfo_x86 *c, bool warn)
297 {
298 	const struct cpuid_dependent_feature *df;
299 
300 	for (df = cpuid_dependent_features; df->feature; df++) {
301 
302 		if (!cpu_has(c, df->feature))
303 			continue;
304 		/*
305 		 * Note: cpuid_level is set to -1 if unavailable, but
306 		 * extended_extended_level is set to 0 if unavailable
307 		 * and the legitimate extended levels are all negative
308 		 * when signed; hence the weird messing around with
309 		 * signs here...
310 		 */
311 		if (!((s32)df->level < 0 ?
312 		     (u32)df->level > (u32)c->extended_cpuid_level :
313 		     (s32)df->level > (s32)c->cpuid_level))
314 			continue;
315 
316 		clear_cpu_cap(c, df->feature);
317 		if (!warn)
318 			continue;
319 
320 		printk(KERN_WARNING
321 		       "CPU: CPU feature %s disabled, no CPUID level 0x%x\n",
322 				x86_cap_flags[df->feature], df->level);
323 	}
324 }
325 
326 /*
327  * Naming convention should be: <Name> [(<Codename>)]
328  * This table only is used unless init_<vendor>() below doesn't set it;
329  * in particular, if CPUID levels 0x80000002..4 are supported, this
330  * isn't used
331  */
332 
333 /* Look up CPU names by table lookup. */
334 static const char *__cpuinit table_lookup_model(struct cpuinfo_x86 *c)
335 {
336 	const struct cpu_model_info *info;
337 
338 	if (c->x86_model >= 16)
339 		return NULL;	/* Range check */
340 
341 	if (!this_cpu)
342 		return NULL;
343 
344 	info = this_cpu->c_models;
345 
346 	while (info && info->family) {
347 		if (info->family == c->x86)
348 			return info->model_names[c->x86_model];
349 		info++;
350 	}
351 	return NULL;		/* Not found */
352 }
353 
354 __u32 cpu_caps_cleared[NCAPINTS] __cpuinitdata;
355 __u32 cpu_caps_set[NCAPINTS] __cpuinitdata;
356 
357 void load_percpu_segment(int cpu)
358 {
359 #ifdef CONFIG_X86_32
360 	loadsegment(fs, __KERNEL_PERCPU);
361 #else
362 	loadsegment(gs, 0);
363 	wrmsrl(MSR_GS_BASE, (unsigned long)per_cpu(irq_stack_union.gs_base, cpu));
364 #endif
365 	load_stack_canary_segment();
366 }
367 
368 /*
369  * Current gdt points %fs at the "master" per-cpu area: after this,
370  * it's on the real one.
371  */
372 void switch_to_new_gdt(int cpu)
373 {
374 	struct desc_ptr gdt_descr;
375 
376 	gdt_descr.address = (long)get_cpu_gdt_table(cpu);
377 	gdt_descr.size = GDT_SIZE - 1;
378 	load_gdt(&gdt_descr);
379 	/* Reload the per-cpu base */
380 
381 	load_percpu_segment(cpu);
382 }
383 
384 static const struct cpu_dev *__cpuinitdata cpu_devs[X86_VENDOR_NUM] = {};
385 
386 static void __cpuinit get_model_name(struct cpuinfo_x86 *c)
387 {
388 	unsigned int *v;
389 	char *p, *q;
390 
391 	if (c->extended_cpuid_level < 0x80000004)
392 		return;
393 
394 	v = (unsigned int *)c->x86_model_id;
395 	cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
396 	cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
397 	cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
398 	c->x86_model_id[48] = 0;
399 
400 	/*
401 	 * Intel chips right-justify this string for some dumb reason;
402 	 * undo that brain damage:
403 	 */
404 	p = q = &c->x86_model_id[0];
405 	while (*p == ' ')
406 		p++;
407 	if (p != q) {
408 		while (*p)
409 			*q++ = *p++;
410 		while (q <= &c->x86_model_id[48])
411 			*q++ = '\0';	/* Zero-pad the rest */
412 	}
413 }
414 
415 void __cpuinit cpu_detect_cache_sizes(struct cpuinfo_x86 *c)
416 {
417 	unsigned int n, dummy, ebx, ecx, edx, l2size;
418 
419 	n = c->extended_cpuid_level;
420 
421 	if (n >= 0x80000005) {
422 		cpuid(0x80000005, &dummy, &ebx, &ecx, &edx);
423 		c->x86_cache_size = (ecx>>24) + (edx>>24);
424 #ifdef CONFIG_X86_64
425 		/* On K8 L1 TLB is inclusive, so don't count it */
426 		c->x86_tlbsize = 0;
427 #endif
428 	}
429 
430 	if (n < 0x80000006)	/* Some chips just has a large L1. */
431 		return;
432 
433 	cpuid(0x80000006, &dummy, &ebx, &ecx, &edx);
434 	l2size = ecx >> 16;
435 
436 #ifdef CONFIG_X86_64
437 	c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff);
438 #else
439 	/* do processor-specific cache resizing */
440 	if (this_cpu->c_size_cache)
441 		l2size = this_cpu->c_size_cache(c, l2size);
442 
443 	/* Allow user to override all this if necessary. */
444 	if (cachesize_override != -1)
445 		l2size = cachesize_override;
446 
447 	if (l2size == 0)
448 		return;		/* Again, no L2 cache is possible */
449 #endif
450 
451 	c->x86_cache_size = l2size;
452 }
453 
454 void __cpuinit detect_ht(struct cpuinfo_x86 *c)
455 {
456 #ifdef CONFIG_X86_HT
457 	u32 eax, ebx, ecx, edx;
458 	int index_msb, core_bits;
459 	static bool printed;
460 
461 	if (!cpu_has(c, X86_FEATURE_HT))
462 		return;
463 
464 	if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
465 		goto out;
466 
467 	if (cpu_has(c, X86_FEATURE_XTOPOLOGY))
468 		return;
469 
470 	cpuid(1, &eax, &ebx, &ecx, &edx);
471 
472 	smp_num_siblings = (ebx & 0xff0000) >> 16;
473 
474 	if (smp_num_siblings == 1) {
475 		printk_once(KERN_INFO "CPU0: Hyper-Threading is disabled\n");
476 		goto out;
477 	}
478 
479 	if (smp_num_siblings <= 1)
480 		goto out;
481 
482 	index_msb = get_count_order(smp_num_siblings);
483 	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);
484 
485 	smp_num_siblings = smp_num_siblings / c->x86_max_cores;
486 
487 	index_msb = get_count_order(smp_num_siblings);
488 
489 	core_bits = get_count_order(c->x86_max_cores);
490 
491 	c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, index_msb) &
492 				       ((1 << core_bits) - 1);
493 
494 out:
495 	if (!printed && (c->x86_max_cores * smp_num_siblings) > 1) {
496 		printk(KERN_INFO  "CPU: Physical Processor ID: %d\n",
497 		       c->phys_proc_id);
498 		printk(KERN_INFO  "CPU: Processor Core ID: %d\n",
499 		       c->cpu_core_id);
500 		printed = 1;
501 	}
502 #endif
503 }
504 
505 static void __cpuinit get_cpu_vendor(struct cpuinfo_x86 *c)
506 {
507 	char *v = c->x86_vendor_id;
508 	int i;
509 
510 	for (i = 0; i < X86_VENDOR_NUM; i++) {
511 		if (!cpu_devs[i])
512 			break;
513 
514 		if (!strcmp(v, cpu_devs[i]->c_ident[0]) ||
515 		    (cpu_devs[i]->c_ident[1] &&
516 		     !strcmp(v, cpu_devs[i]->c_ident[1]))) {
517 
518 			this_cpu = cpu_devs[i];
519 			c->x86_vendor = this_cpu->c_x86_vendor;
520 			return;
521 		}
522 	}
523 
524 	printk_once(KERN_ERR
525 			"CPU: vendor_id '%s' unknown, using generic init.\n" \
526 			"CPU: Your system may be unstable.\n", v);
527 
528 	c->x86_vendor = X86_VENDOR_UNKNOWN;
529 	this_cpu = &default_cpu;
530 }
531 
532 void __cpuinit cpu_detect(struct cpuinfo_x86 *c)
533 {
534 	/* Get vendor name */
535 	cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
536 	      (unsigned int *)&c->x86_vendor_id[0],
537 	      (unsigned int *)&c->x86_vendor_id[8],
538 	      (unsigned int *)&c->x86_vendor_id[4]);
539 
540 	c->x86 = 4;
541 	/* Intel-defined flags: level 0x00000001 */
542 	if (c->cpuid_level >= 0x00000001) {
543 		u32 junk, tfms, cap0, misc;
544 
545 		cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
546 		c->x86 = (tfms >> 8) & 0xf;
547 		c->x86_model = (tfms >> 4) & 0xf;
548 		c->x86_mask = tfms & 0xf;
549 
550 		if (c->x86 == 0xf)
551 			c->x86 += (tfms >> 20) & 0xff;
552 		if (c->x86 >= 0x6)
553 			c->x86_model += ((tfms >> 16) & 0xf) << 4;
554 
555 		if (cap0 & (1<<19)) {
556 			c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
557 			c->x86_cache_alignment = c->x86_clflush_size;
558 		}
559 	}
560 }
561 
562 void __cpuinit get_cpu_cap(struct cpuinfo_x86 *c)
563 {
564 	u32 tfms, xlvl;
565 	u32 ebx;
566 
567 	/* Intel-defined flags: level 0x00000001 */
568 	if (c->cpuid_level >= 0x00000001) {
569 		u32 capability, excap;
570 
571 		cpuid(0x00000001, &tfms, &ebx, &excap, &capability);
572 		c->x86_capability[0] = capability;
573 		c->x86_capability[4] = excap;
574 	}
575 
576 	/* Additional Intel-defined flags: level 0x00000007 */
577 	if (c->cpuid_level >= 0x00000007) {
578 		u32 eax, ebx, ecx, edx;
579 
580 		cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx);
581 
582 		c->x86_capability[9] = ebx;
583 	}
584 
585 	/* AMD-defined flags: level 0x80000001 */
586 	xlvl = cpuid_eax(0x80000000);
587 	c->extended_cpuid_level = xlvl;
588 
589 	if ((xlvl & 0xffff0000) == 0x80000000) {
590 		if (xlvl >= 0x80000001) {
591 			c->x86_capability[1] = cpuid_edx(0x80000001);
592 			c->x86_capability[6] = cpuid_ecx(0x80000001);
593 		}
594 	}
595 
596 	if (c->extended_cpuid_level >= 0x80000008) {
597 		u32 eax = cpuid_eax(0x80000008);
598 
599 		c->x86_virt_bits = (eax >> 8) & 0xff;
600 		c->x86_phys_bits = eax & 0xff;
601 	}
602 #ifdef CONFIG_X86_32
603 	else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36))
604 		c->x86_phys_bits = 36;
605 #endif
606 
607 	if (c->extended_cpuid_level >= 0x80000007)
608 		c->x86_power = cpuid_edx(0x80000007);
609 
610 	init_scattered_cpuid_features(c);
611 }
612 
613 static void __cpuinit identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
614 {
615 #ifdef CONFIG_X86_32
616 	int i;
617 
618 	/*
619 	 * First of all, decide if this is a 486 or higher
620 	 * It's a 486 if we can modify the AC flag
621 	 */
622 	if (flag_is_changeable_p(X86_EFLAGS_AC))
623 		c->x86 = 4;
624 	else
625 		c->x86 = 3;
626 
627 	for (i = 0; i < X86_VENDOR_NUM; i++)
628 		if (cpu_devs[i] && cpu_devs[i]->c_identify) {
629 			c->x86_vendor_id[0] = 0;
630 			cpu_devs[i]->c_identify(c);
631 			if (c->x86_vendor_id[0]) {
632 				get_cpu_vendor(c);
633 				break;
634 			}
635 		}
636 #endif
637 }
638 
639 /*
640  * Do minimum CPU detection early.
641  * Fields really needed: vendor, cpuid_level, family, model, mask,
642  * cache alignment.
643  * The others are not touched to avoid unwanted side effects.
644  *
645  * WARNING: this function is only called on the BP.  Don't add code here
646  * that is supposed to run on all CPUs.
647  */
648 static void __init early_identify_cpu(struct cpuinfo_x86 *c)
649 {
650 #ifdef CONFIG_X86_64
651 	c->x86_clflush_size = 64;
652 	c->x86_phys_bits = 36;
653 	c->x86_virt_bits = 48;
654 #else
655 	c->x86_clflush_size = 32;
656 	c->x86_phys_bits = 32;
657 	c->x86_virt_bits = 32;
658 #endif
659 	c->x86_cache_alignment = c->x86_clflush_size;
660 
661 	memset(&c->x86_capability, 0, sizeof c->x86_capability);
662 	c->extended_cpuid_level = 0;
663 
664 	if (!have_cpuid_p())
665 		identify_cpu_without_cpuid(c);
666 
667 	/* cyrix could have cpuid enabled via c_identify()*/
668 	if (!have_cpuid_p())
669 		return;
670 
671 	cpu_detect(c);
672 
673 	get_cpu_vendor(c);
674 
675 	get_cpu_cap(c);
676 
677 	if (this_cpu->c_early_init)
678 		this_cpu->c_early_init(c);
679 
680 	c->cpu_index = 0;
681 	filter_cpuid_features(c, false);
682 
683 	setup_smep(c);
684 
685 	if (this_cpu->c_bsp_init)
686 		this_cpu->c_bsp_init(c);
687 }
688 
689 void __init early_cpu_init(void)
690 {
691 	const struct cpu_dev *const *cdev;
692 	int count = 0;
693 
694 #ifdef CONFIG_PROCESSOR_SELECT
695 	printk(KERN_INFO "KERNEL supported cpus:\n");
696 #endif
697 
698 	for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) {
699 		const struct cpu_dev *cpudev = *cdev;
700 
701 		if (count >= X86_VENDOR_NUM)
702 			break;
703 		cpu_devs[count] = cpudev;
704 		count++;
705 
706 #ifdef CONFIG_PROCESSOR_SELECT
707 		{
708 			unsigned int j;
709 
710 			for (j = 0; j < 2; j++) {
711 				if (!cpudev->c_ident[j])
712 					continue;
713 				printk(KERN_INFO "  %s %s\n", cpudev->c_vendor,
714 					cpudev->c_ident[j]);
715 			}
716 		}
717 #endif
718 	}
719 	early_identify_cpu(&boot_cpu_data);
720 }
721 
722 /*
723  * The NOPL instruction is supposed to exist on all CPUs of family >= 6;
724  * unfortunately, that's not true in practice because of early VIA
725  * chips and (more importantly) broken virtualizers that are not easy
726  * to detect. In the latter case it doesn't even *fail* reliably, so
727  * probing for it doesn't even work. Disable it completely on 32-bit
728  * unless we can find a reliable way to detect all the broken cases.
729  * Enable it explicitly on 64-bit for non-constant inputs of cpu_has().
730  */
731 static void __cpuinit detect_nopl(struct cpuinfo_x86 *c)
732 {
733 #ifdef CONFIG_X86_32
734 	clear_cpu_cap(c, X86_FEATURE_NOPL);
735 #else
736 	set_cpu_cap(c, X86_FEATURE_NOPL);
737 #endif
738 }
739 
740 static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
741 {
742 	c->extended_cpuid_level = 0;
743 
744 	if (!have_cpuid_p())
745 		identify_cpu_without_cpuid(c);
746 
747 	/* cyrix could have cpuid enabled via c_identify()*/
748 	if (!have_cpuid_p())
749 		return;
750 
751 	cpu_detect(c);
752 
753 	get_cpu_vendor(c);
754 
755 	get_cpu_cap(c);
756 
757 	if (c->cpuid_level >= 0x00000001) {
758 		c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF;
759 #ifdef CONFIG_X86_32
760 # ifdef CONFIG_X86_HT
761 		c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
762 # else
763 		c->apicid = c->initial_apicid;
764 # endif
765 #endif
766 		c->phys_proc_id = c->initial_apicid;
767 	}
768 
769 	setup_smep(c);
770 
771 	get_model_name(c); /* Default name */
772 
773 	detect_nopl(c);
774 }
775 
776 /*
777  * This does the hard work of actually picking apart the CPU stuff...
778  */
779 static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
780 {
781 	int i;
782 
783 	c->loops_per_jiffy = loops_per_jiffy;
784 	c->x86_cache_size = -1;
785 	c->x86_vendor = X86_VENDOR_UNKNOWN;
786 	c->x86_model = c->x86_mask = 0;	/* So far unknown... */
787 	c->x86_vendor_id[0] = '\0'; /* Unset */
788 	c->x86_model_id[0] = '\0';  /* Unset */
789 	c->x86_max_cores = 1;
790 	c->x86_coreid_bits = 0;
791 #ifdef CONFIG_X86_64
792 	c->x86_clflush_size = 64;
793 	c->x86_phys_bits = 36;
794 	c->x86_virt_bits = 48;
795 #else
796 	c->cpuid_level = -1;	/* CPUID not detected */
797 	c->x86_clflush_size = 32;
798 	c->x86_phys_bits = 32;
799 	c->x86_virt_bits = 32;
800 #endif
801 	c->x86_cache_alignment = c->x86_clflush_size;
802 	memset(&c->x86_capability, 0, sizeof c->x86_capability);
803 
804 	generic_identify(c);
805 
806 	if (this_cpu->c_identify)
807 		this_cpu->c_identify(c);
808 
809 	/* Clear/Set all flags overriden by options, after probe */
810 	for (i = 0; i < NCAPINTS; i++) {
811 		c->x86_capability[i] &= ~cpu_caps_cleared[i];
812 		c->x86_capability[i] |= cpu_caps_set[i];
813 	}
814 
815 #ifdef CONFIG_X86_64
816 	c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
817 #endif
818 
819 	/*
820 	 * Vendor-specific initialization.  In this section we
821 	 * canonicalize the feature flags, meaning if there are
822 	 * features a certain CPU supports which CPUID doesn't
823 	 * tell us, CPUID claiming incorrect flags, or other bugs,
824 	 * we handle them here.
825 	 *
826 	 * At the end of this section, c->x86_capability better
827 	 * indicate the features this CPU genuinely supports!
828 	 */
829 	if (this_cpu->c_init)
830 		this_cpu->c_init(c);
831 
832 	/* Disable the PN if appropriate */
833 	squash_the_stupid_serial_number(c);
834 
835 	/*
836 	 * The vendor-specific functions might have changed features.
837 	 * Now we do "generic changes."
838 	 */
839 
840 	/* Filter out anything that depends on CPUID levels we don't have */
841 	filter_cpuid_features(c, true);
842 
843 	/* If the model name is still unset, do table lookup. */
844 	if (!c->x86_model_id[0]) {
845 		const char *p;
846 		p = table_lookup_model(c);
847 		if (p)
848 			strcpy(c->x86_model_id, p);
849 		else
850 			/* Last resort... */
851 			sprintf(c->x86_model_id, "%02x/%02x",
852 				c->x86, c->x86_model);
853 	}
854 
855 #ifdef CONFIG_X86_64
856 	detect_ht(c);
857 #endif
858 
859 	init_hypervisor(c);
860 	x86_init_rdrand(c);
861 
862 	/*
863 	 * Clear/Set all flags overriden by options, need do it
864 	 * before following smp all cpus cap AND.
865 	 */
866 	for (i = 0; i < NCAPINTS; i++) {
867 		c->x86_capability[i] &= ~cpu_caps_cleared[i];
868 		c->x86_capability[i] |= cpu_caps_set[i];
869 	}
870 
871 	/*
872 	 * On SMP, boot_cpu_data holds the common feature set between
873 	 * all CPUs; so make sure that we indicate which features are
874 	 * common between the CPUs.  The first time this routine gets
875 	 * executed, c == &boot_cpu_data.
876 	 */
877 	if (c != &boot_cpu_data) {
878 		/* AND the already accumulated flags with these */
879 		for (i = 0; i < NCAPINTS; i++)
880 			boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
881 	}
882 
883 	/* Init Machine Check Exception if available. */
884 	mcheck_cpu_init(c);
885 
886 	select_idle_routine(c);
887 
888 #ifdef CONFIG_NUMA
889 	numa_add_cpu(smp_processor_id());
890 #endif
891 }
892 
893 #ifdef CONFIG_X86_64
894 static void vgetcpu_set_mode(void)
895 {
896 	if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))
897 		vgetcpu_mode = VGETCPU_RDTSCP;
898 	else
899 		vgetcpu_mode = VGETCPU_LSL;
900 }
901 #endif
902 
903 void __init identify_boot_cpu(void)
904 {
905 	identify_cpu(&boot_cpu_data);
906 	init_amd_e400_c1e_mask();
907 #ifdef CONFIG_X86_32
908 	sysenter_setup();
909 	enable_sep_cpu();
910 #else
911 	vgetcpu_set_mode();
912 #endif
913 }
914 
915 void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
916 {
917 	BUG_ON(c == &boot_cpu_data);
918 	identify_cpu(c);
919 #ifdef CONFIG_X86_32
920 	enable_sep_cpu();
921 #endif
922 	mtrr_ap_init();
923 }
924 
925 struct msr_range {
926 	unsigned	min;
927 	unsigned	max;
928 };
929 
930 static const struct msr_range msr_range_array[] __cpuinitconst = {
931 	{ 0x00000000, 0x00000418},
932 	{ 0xc0000000, 0xc000040b},
933 	{ 0xc0010000, 0xc0010142},
934 	{ 0xc0011000, 0xc001103b},
935 };
936 
937 static void __cpuinit __print_cpu_msr(void)
938 {
939 	unsigned index_min, index_max;
940 	unsigned index;
941 	u64 val;
942 	int i;
943 
944 	for (i = 0; i < ARRAY_SIZE(msr_range_array); i++) {
945 		index_min = msr_range_array[i].min;
946 		index_max = msr_range_array[i].max;
947 
948 		for (index = index_min; index < index_max; index++) {
949 			if (rdmsrl_amd_safe(index, &val))
950 				continue;
951 			printk(KERN_INFO " MSR%08x: %016llx\n", index, val);
952 		}
953 	}
954 }
955 
956 static int show_msr __cpuinitdata;
957 
958 static __init int setup_show_msr(char *arg)
959 {
960 	int num;
961 
962 	get_option(&arg, &num);
963 
964 	if (num > 0)
965 		show_msr = num;
966 	return 1;
967 }
968 __setup("show_msr=", setup_show_msr);
969 
970 static __init int setup_noclflush(char *arg)
971 {
972 	setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
973 	return 1;
974 }
975 __setup("noclflush", setup_noclflush);
976 
977 void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
978 {
979 	const char *vendor = NULL;
980 
981 	if (c->x86_vendor < X86_VENDOR_NUM) {
982 		vendor = this_cpu->c_vendor;
983 	} else {
984 		if (c->cpuid_level >= 0)
985 			vendor = c->x86_vendor_id;
986 	}
987 
988 	if (vendor && !strstr(c->x86_model_id, vendor))
989 		printk(KERN_CONT "%s ", vendor);
990 
991 	if (c->x86_model_id[0])
992 		printk(KERN_CONT "%s", c->x86_model_id);
993 	else
994 		printk(KERN_CONT "%d86", c->x86);
995 
996 	if (c->x86_mask || c->cpuid_level >= 0)
997 		printk(KERN_CONT " stepping %02x\n", c->x86_mask);
998 	else
999 		printk(KERN_CONT "\n");
1000 
1001 	__print_cpu_msr();
1002 }
1003 
1004 void __cpuinit print_cpu_msr(struct cpuinfo_x86 *c)
1005 {
1006 	if (c->cpu_index < show_msr)
1007 		__print_cpu_msr();
1008 }
1009 
1010 static __init int setup_disablecpuid(char *arg)
1011 {
1012 	int bit;
1013 
1014 	if (get_option(&arg, &bit) && bit < NCAPINTS*32)
1015 		setup_clear_cpu_cap(bit);
1016 	else
1017 		return 0;
1018 
1019 	return 1;
1020 }
1021 __setup("clearcpuid=", setup_disablecpuid);
1022 
1023 #ifdef CONFIG_X86_64
1024 struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
1025 struct desc_ptr nmi_idt_descr = { NR_VECTORS * 16 - 1,
1026 				    (unsigned long) nmi_idt_table };
1027 
1028 DEFINE_PER_CPU_FIRST(union irq_stack_union,
1029 		     irq_stack_union) __aligned(PAGE_SIZE);
1030 
1031 /*
1032  * The following four percpu variables are hot.  Align current_task to
1033  * cacheline size such that all four fall in the same cacheline.
1034  */
1035 DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
1036 	&init_task;
1037 EXPORT_PER_CPU_SYMBOL(current_task);
1038 
1039 DEFINE_PER_CPU(unsigned long, kernel_stack) =
1040 	(unsigned long)&init_thread_union - KERNEL_STACK_OFFSET + THREAD_SIZE;
1041 EXPORT_PER_CPU_SYMBOL(kernel_stack);
1042 
1043 DEFINE_PER_CPU(char *, irq_stack_ptr) =
1044 	init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64;
1045 
1046 DEFINE_PER_CPU(unsigned int, irq_count) = -1;
1047 
1048 DEFINE_PER_CPU(struct task_struct *, fpu_owner_task);
1049 
1050 /*
1051  * Special IST stacks which the CPU switches to when it calls
1052  * an IST-marked descriptor entry. Up to 7 stacks (hardware
1053  * limit), all of them are 4K, except the debug stack which
1054  * is 8K.
1055  */
1056 static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
1057 	  [0 ... N_EXCEPTION_STACKS - 1]	= EXCEPTION_STKSZ,
1058 	  [DEBUG_STACK - 1]			= DEBUG_STKSZ
1059 };
1060 
1061 static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
1062 	[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
1063 
1064 /* May not be marked __init: used by software suspend */
1065 void syscall_init(void)
1066 {
1067 	/*
1068 	 * LSTAR and STAR live in a bit strange symbiosis.
1069 	 * They both write to the same internal register. STAR allows to
1070 	 * set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
1071 	 */
1072 	wrmsrl(MSR_STAR,  ((u64)__USER32_CS)<<48  | ((u64)__KERNEL_CS)<<32);
1073 	wrmsrl(MSR_LSTAR, system_call);
1074 	wrmsrl(MSR_CSTAR, ignore_sysret);
1075 
1076 #ifdef CONFIG_IA32_EMULATION
1077 	syscall32_cpu_init();
1078 #endif
1079 
1080 	/* Flags to clear on syscall */
1081 	wrmsrl(MSR_SYSCALL_MASK,
1082 	       X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF|X86_EFLAGS_IOPL);
1083 }
1084 
1085 unsigned long kernel_eflags;
1086 
1087 /*
1088  * Copies of the original ist values from the tss are only accessed during
1089  * debugging, no special alignment required.
1090  */
1091 DEFINE_PER_CPU(struct orig_ist, orig_ist);
1092 
1093 static DEFINE_PER_CPU(unsigned long, debug_stack_addr);
1094 DEFINE_PER_CPU(int, debug_stack_usage);
1095 
1096 int is_debug_stack(unsigned long addr)
1097 {
1098 	return __get_cpu_var(debug_stack_usage) ||
1099 		(addr <= __get_cpu_var(debug_stack_addr) &&
1100 		 addr > (__get_cpu_var(debug_stack_addr) - DEBUG_STKSZ));
1101 }
1102 
1103 void debug_stack_set_zero(void)
1104 {
1105 	load_idt((const struct desc_ptr *)&nmi_idt_descr);
1106 }
1107 
1108 void debug_stack_reset(void)
1109 {
1110 	load_idt((const struct desc_ptr *)&idt_descr);
1111 }
1112 
1113 #else	/* CONFIG_X86_64 */
1114 
1115 DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
1116 EXPORT_PER_CPU_SYMBOL(current_task);
1117 DEFINE_PER_CPU(struct task_struct *, fpu_owner_task);
1118 
1119 #ifdef CONFIG_CC_STACKPROTECTOR
1120 DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary);
1121 #endif
1122 
1123 /* Make sure %fs and %gs are initialized properly in idle threads */
1124 struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
1125 {
1126 	memset(regs, 0, sizeof(struct pt_regs));
1127 	regs->fs = __KERNEL_PERCPU;
1128 	regs->gs = __KERNEL_STACK_CANARY;
1129 
1130 	return regs;
1131 }
1132 #endif	/* CONFIG_X86_64 */
1133 
1134 /*
1135  * Clear all 6 debug registers:
1136  */
1137 static void clear_all_debug_regs(void)
1138 {
1139 	int i;
1140 
1141 	for (i = 0; i < 8; i++) {
1142 		/* Ignore db4, db5 */
1143 		if ((i == 4) || (i == 5))
1144 			continue;
1145 
1146 		set_debugreg(0, i);
1147 	}
1148 }
1149 
1150 #ifdef CONFIG_KGDB
1151 /*
1152  * Restore debug regs if using kgdbwait and you have a kernel debugger
1153  * connection established.
1154  */
1155 static void dbg_restore_debug_regs(void)
1156 {
1157 	if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break))
1158 		arch_kgdb_ops.correct_hw_break();
1159 }
1160 #else /* ! CONFIG_KGDB */
1161 #define dbg_restore_debug_regs()
1162 #endif /* ! CONFIG_KGDB */
1163 
1164 /*
1165  * Prints an error where the NUMA and configured core-number mismatch and the
1166  * platform didn't override this to fix it up
1167  */
1168 void __cpuinit x86_default_fixup_cpu_id(struct cpuinfo_x86 *c, int node)
1169 {
1170 	pr_err("NUMA core number %d differs from configured core number %d\n", node, c->phys_proc_id);
1171 }
1172 
1173 /*
1174  * cpu_init() initializes state that is per-CPU. Some data is already
1175  * initialized (naturally) in the bootstrap process, such as the GDT
1176  * and IDT. We reload them nevertheless, this function acts as a
1177  * 'CPU state barrier', nothing should get across.
1178  * A lot of state is already set up in PDA init for 64 bit
1179  */
1180 #ifdef CONFIG_X86_64
1181 
1182 void __cpuinit cpu_init(void)
1183 {
1184 	struct orig_ist *oist;
1185 	struct task_struct *me;
1186 	struct tss_struct *t;
1187 	unsigned long v;
1188 	int cpu;
1189 	int i;
1190 
1191 	cpu = stack_smp_processor_id();
1192 	t = &per_cpu(init_tss, cpu);
1193 	oist = &per_cpu(orig_ist, cpu);
1194 
1195 #ifdef CONFIG_NUMA
1196 	if (cpu != 0 && percpu_read(numa_node) == 0 &&
1197 	    early_cpu_to_node(cpu) != NUMA_NO_NODE)
1198 		set_numa_node(early_cpu_to_node(cpu));
1199 #endif
1200 
1201 	me = current;
1202 
1203 	if (cpumask_test_and_set_cpu(cpu, cpu_initialized_mask))
1204 		panic("CPU#%d already initialized!\n", cpu);
1205 
1206 	pr_debug("Initializing CPU#%d\n", cpu);
1207 
1208 	clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
1209 
1210 	/*
1211 	 * Initialize the per-CPU GDT with the boot GDT,
1212 	 * and set up the GDT descriptor:
1213 	 */
1214 
1215 	switch_to_new_gdt(cpu);
1216 	loadsegment(fs, 0);
1217 
1218 	load_idt((const struct desc_ptr *)&idt_descr);
1219 
1220 	memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);
1221 	syscall_init();
1222 
1223 	wrmsrl(MSR_FS_BASE, 0);
1224 	wrmsrl(MSR_KERNEL_GS_BASE, 0);
1225 	barrier();
1226 
1227 	x86_configure_nx();
1228 	if (cpu != 0)
1229 		enable_x2apic();
1230 
1231 	/*
1232 	 * set up and load the per-CPU TSS
1233 	 */
1234 	if (!oist->ist[0]) {
1235 		char *estacks = per_cpu(exception_stacks, cpu);
1236 
1237 		for (v = 0; v < N_EXCEPTION_STACKS; v++) {
1238 			estacks += exception_stack_sizes[v];
1239 			oist->ist[v] = t->x86_tss.ist[v] =
1240 					(unsigned long)estacks;
1241 			if (v == DEBUG_STACK-1)
1242 				per_cpu(debug_stack_addr, cpu) = (unsigned long)estacks;
1243 		}
1244 	}
1245 
1246 	t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
1247 
1248 	/*
1249 	 * <= is required because the CPU will access up to
1250 	 * 8 bits beyond the end of the IO permission bitmap.
1251 	 */
1252 	for (i = 0; i <= IO_BITMAP_LONGS; i++)
1253 		t->io_bitmap[i] = ~0UL;
1254 
1255 	atomic_inc(&init_mm.mm_count);
1256 	me->active_mm = &init_mm;
1257 	BUG_ON(me->mm);
1258 	enter_lazy_tlb(&init_mm, me);
1259 
1260 	load_sp0(t, &current->thread);
1261 	set_tss_desc(cpu, t);
1262 	load_TR_desc();
1263 	load_LDT(&init_mm.context);
1264 
1265 	clear_all_debug_regs();
1266 	dbg_restore_debug_regs();
1267 
1268 	fpu_init();
1269 	xsave_init();
1270 
1271 	raw_local_save_flags(kernel_eflags);
1272 
1273 	if (is_uv_system())
1274 		uv_cpu_init();
1275 }
1276 
1277 #else
1278 
1279 void __cpuinit cpu_init(void)
1280 {
1281 	int cpu = smp_processor_id();
1282 	struct task_struct *curr = current;
1283 	struct tss_struct *t = &per_cpu(init_tss, cpu);
1284 	struct thread_struct *thread = &curr->thread;
1285 
1286 	if (cpumask_test_and_set_cpu(cpu, cpu_initialized_mask)) {
1287 		printk(KERN_WARNING "CPU#%d already initialized!\n", cpu);
1288 		for (;;)
1289 			local_irq_enable();
1290 	}
1291 
1292 	printk(KERN_INFO "Initializing CPU#%d\n", cpu);
1293 
1294 	if (cpu_has_vme || cpu_has_tsc || cpu_has_de)
1295 		clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
1296 
1297 	load_idt(&idt_descr);
1298 	switch_to_new_gdt(cpu);
1299 
1300 	/*
1301 	 * Set up and load the per-CPU TSS and LDT
1302 	 */
1303 	atomic_inc(&init_mm.mm_count);
1304 	curr->active_mm = &init_mm;
1305 	BUG_ON(curr->mm);
1306 	enter_lazy_tlb(&init_mm, curr);
1307 
1308 	load_sp0(t, thread);
1309 	set_tss_desc(cpu, t);
1310 	load_TR_desc();
1311 	load_LDT(&init_mm.context);
1312 
1313 	t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
1314 
1315 #ifdef CONFIG_DOUBLEFAULT
1316 	/* Set up doublefault TSS pointer in the GDT */
1317 	__set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
1318 #endif
1319 
1320 	clear_all_debug_regs();
1321 	dbg_restore_debug_regs();
1322 
1323 	fpu_init();
1324 	xsave_init();
1325 }
1326 #endif
1327