xref: /openbmc/linux/arch/x86/kernel/cpu/common.c (revision 1eb4c977)
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/debugreg.h>
22 #include <asm/sections.h>
23 #include <linux/topology.h>
24 #include <linux/cpumask.h>
25 #include <asm/pgtable.h>
26 #include <linux/atomic.h>
27 #include <asm/proto.h>
28 #include <asm/setup.h>
29 #include <asm/apic.h>
30 #include <asm/desc.h>
31 #include <asm/i387.h>
32 #include <asm/fpu-internal.h>
33 #include <asm/mtrr.h>
34 #include <linux/numa.h>
35 #include <asm/asm.h>
36 #include <asm/cpu.h>
37 #include <asm/mce.h>
38 #include <asm/msr.h>
39 #include <asm/pat.h>
40 
41 #ifdef CONFIG_X86_LOCAL_APIC
42 #include <asm/uv/uv.h>
43 #endif
44 
45 #include "cpu.h"
46 
47 /* all of these masks are initialized in setup_cpu_local_masks() */
48 cpumask_var_t cpu_initialized_mask;
49 cpumask_var_t cpu_callout_mask;
50 cpumask_var_t cpu_callin_mask;
51 
52 /* representing cpus for which sibling maps can be computed */
53 cpumask_var_t cpu_sibling_setup_mask;
54 
55 /* correctly size the local cpu masks */
56 void __init setup_cpu_local_masks(void)
57 {
58 	alloc_bootmem_cpumask_var(&cpu_initialized_mask);
59 	alloc_bootmem_cpumask_var(&cpu_callin_mask);
60 	alloc_bootmem_cpumask_var(&cpu_callout_mask);
61 	alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask);
62 }
63 
64 static void __cpuinit default_init(struct cpuinfo_x86 *c)
65 {
66 #ifdef CONFIG_X86_64
67 	cpu_detect_cache_sizes(c);
68 #else
69 	/* Not much we can do here... */
70 	/* Check if at least it has cpuid */
71 	if (c->cpuid_level == -1) {
72 		/* No cpuid. It must be an ancient CPU */
73 		if (c->x86 == 4)
74 			strcpy(c->x86_model_id, "486");
75 		else if (c->x86 == 3)
76 			strcpy(c->x86_model_id, "386");
77 	}
78 #endif
79 }
80 
81 static const struct cpu_dev __cpuinitconst default_cpu = {
82 	.c_init		= default_init,
83 	.c_vendor	= "Unknown",
84 	.c_x86_vendor	= X86_VENDOR_UNKNOWN,
85 };
86 
87 static const struct cpu_dev *this_cpu __cpuinitdata = &default_cpu;
88 
89 DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = {
90 #ifdef CONFIG_X86_64
91 	/*
92 	 * We need valid kernel segments for data and code in long mode too
93 	 * IRET will check the segment types  kkeil 2000/10/28
94 	 * Also sysret mandates a special GDT layout
95 	 *
96 	 * TLS descriptors are currently at a different place compared to i386.
97 	 * Hopefully nobody expects them at a fixed place (Wine?)
98 	 */
99 	[GDT_ENTRY_KERNEL32_CS]		= GDT_ENTRY_INIT(0xc09b, 0, 0xfffff),
100 	[GDT_ENTRY_KERNEL_CS]		= GDT_ENTRY_INIT(0xa09b, 0, 0xfffff),
101 	[GDT_ENTRY_KERNEL_DS]		= GDT_ENTRY_INIT(0xc093, 0, 0xfffff),
102 	[GDT_ENTRY_DEFAULT_USER32_CS]	= GDT_ENTRY_INIT(0xc0fb, 0, 0xfffff),
103 	[GDT_ENTRY_DEFAULT_USER_DS]	= GDT_ENTRY_INIT(0xc0f3, 0, 0xfffff),
104 	[GDT_ENTRY_DEFAULT_USER_CS]	= GDT_ENTRY_INIT(0xa0fb, 0, 0xfffff),
105 #else
106 	[GDT_ENTRY_KERNEL_CS]		= GDT_ENTRY_INIT(0xc09a, 0, 0xfffff),
107 	[GDT_ENTRY_KERNEL_DS]		= GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
108 	[GDT_ENTRY_DEFAULT_USER_CS]	= GDT_ENTRY_INIT(0xc0fa, 0, 0xfffff),
109 	[GDT_ENTRY_DEFAULT_USER_DS]	= GDT_ENTRY_INIT(0xc0f2, 0, 0xfffff),
110 	/*
111 	 * Segments used for calling PnP BIOS have byte granularity.
112 	 * They code segments and data segments have fixed 64k limits,
113 	 * the transfer segment sizes are set at run time.
114 	 */
115 	/* 32-bit code */
116 	[GDT_ENTRY_PNPBIOS_CS32]	= GDT_ENTRY_INIT(0x409a, 0, 0xffff),
117 	/* 16-bit code */
118 	[GDT_ENTRY_PNPBIOS_CS16]	= GDT_ENTRY_INIT(0x009a, 0, 0xffff),
119 	/* 16-bit data */
120 	[GDT_ENTRY_PNPBIOS_DS]		= GDT_ENTRY_INIT(0x0092, 0, 0xffff),
121 	/* 16-bit data */
122 	[GDT_ENTRY_PNPBIOS_TS1]		= GDT_ENTRY_INIT(0x0092, 0, 0),
123 	/* 16-bit data */
124 	[GDT_ENTRY_PNPBIOS_TS2]		= GDT_ENTRY_INIT(0x0092, 0, 0),
125 	/*
126 	 * The APM segments have byte granularity and their bases
127 	 * are set at run time.  All have 64k limits.
128 	 */
129 	/* 32-bit code */
130 	[GDT_ENTRY_APMBIOS_BASE]	= GDT_ENTRY_INIT(0x409a, 0, 0xffff),
131 	/* 16-bit code */
132 	[GDT_ENTRY_APMBIOS_BASE+1]	= GDT_ENTRY_INIT(0x009a, 0, 0xffff),
133 	/* data */
134 	[GDT_ENTRY_APMBIOS_BASE+2]	= GDT_ENTRY_INIT(0x4092, 0, 0xffff),
135 
136 	[GDT_ENTRY_ESPFIX_SS]		= GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
137 	[GDT_ENTRY_PERCPU]		= GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
138 	GDT_STACK_CANARY_INIT
139 #endif
140 } };
141 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
142 
143 static int __init x86_xsave_setup(char *s)
144 {
145 	setup_clear_cpu_cap(X86_FEATURE_XSAVE);
146 	setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
147 	return 1;
148 }
149 __setup("noxsave", x86_xsave_setup);
150 
151 static int __init x86_xsaveopt_setup(char *s)
152 {
153 	setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
154 	return 1;
155 }
156 __setup("noxsaveopt", x86_xsaveopt_setup);
157 
158 #ifdef CONFIG_X86_32
159 static int cachesize_override __cpuinitdata = -1;
160 static int disable_x86_serial_nr __cpuinitdata = 1;
161 
162 static int __init cachesize_setup(char *str)
163 {
164 	get_option(&str, &cachesize_override);
165 	return 1;
166 }
167 __setup("cachesize=", cachesize_setup);
168 
169 static int __init x86_fxsr_setup(char *s)
170 {
171 	setup_clear_cpu_cap(X86_FEATURE_FXSR);
172 	setup_clear_cpu_cap(X86_FEATURE_XMM);
173 	return 1;
174 }
175 __setup("nofxsr", x86_fxsr_setup);
176 
177 static int __init x86_sep_setup(char *s)
178 {
179 	setup_clear_cpu_cap(X86_FEATURE_SEP);
180 	return 1;
181 }
182 __setup("nosep", x86_sep_setup);
183 
184 /* Standard macro to see if a specific flag is changeable */
185 static inline int flag_is_changeable_p(u32 flag)
186 {
187 	u32 f1, f2;
188 
189 	/*
190 	 * Cyrix and IDT cpus allow disabling of CPUID
191 	 * so the code below may return different results
192 	 * when it is executed before and after enabling
193 	 * the CPUID. Add "volatile" to not allow gcc to
194 	 * optimize the subsequent calls to this function.
195 	 */
196 	asm volatile ("pushfl		\n\t"
197 		      "pushfl		\n\t"
198 		      "popl %0		\n\t"
199 		      "movl %0, %1	\n\t"
200 		      "xorl %2, %0	\n\t"
201 		      "pushl %0		\n\t"
202 		      "popfl		\n\t"
203 		      "pushfl		\n\t"
204 		      "popl %0		\n\t"
205 		      "popfl		\n\t"
206 
207 		      : "=&r" (f1), "=&r" (f2)
208 		      : "ir" (flag));
209 
210 	return ((f1^f2) & flag) != 0;
211 }
212 
213 /* Probe for the CPUID instruction */
214 static int __cpuinit have_cpuid_p(void)
215 {
216 	return flag_is_changeable_p(X86_EFLAGS_ID);
217 }
218 
219 static void __cpuinit squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
220 {
221 	unsigned long lo, hi;
222 
223 	if (!cpu_has(c, X86_FEATURE_PN) || !disable_x86_serial_nr)
224 		return;
225 
226 	/* Disable processor serial number: */
227 
228 	rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
229 	lo |= 0x200000;
230 	wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
231 
232 	printk(KERN_NOTICE "CPU serial number disabled.\n");
233 	clear_cpu_cap(c, X86_FEATURE_PN);
234 
235 	/* Disabling the serial number may affect the cpuid level */
236 	c->cpuid_level = cpuid_eax(0);
237 }
238 
239 static int __init x86_serial_nr_setup(char *s)
240 {
241 	disable_x86_serial_nr = 0;
242 	return 1;
243 }
244 __setup("serialnumber", x86_serial_nr_setup);
245 #else
246 static inline int flag_is_changeable_p(u32 flag)
247 {
248 	return 1;
249 }
250 /* Probe for the CPUID instruction */
251 static inline int have_cpuid_p(void)
252 {
253 	return 1;
254 }
255 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
256 {
257 }
258 #endif
259 
260 static int disable_smep __cpuinitdata;
261 static __init int setup_disable_smep(char *arg)
262 {
263 	disable_smep = 1;
264 	return 1;
265 }
266 __setup("nosmep", setup_disable_smep);
267 
268 static __cpuinit void setup_smep(struct cpuinfo_x86 *c)
269 {
270 	if (cpu_has(c, X86_FEATURE_SMEP)) {
271 		if (unlikely(disable_smep)) {
272 			setup_clear_cpu_cap(X86_FEATURE_SMEP);
273 			clear_in_cr4(X86_CR4_SMEP);
274 		} else
275 			set_in_cr4(X86_CR4_SMEP);
276 	}
277 }
278 
279 /*
280  * Some CPU features depend on higher CPUID levels, which may not always
281  * be available due to CPUID level capping or broken virtualization
282  * software.  Add those features to this table to auto-disable them.
283  */
284 struct cpuid_dependent_feature {
285 	u32 feature;
286 	u32 level;
287 };
288 
289 static const struct cpuid_dependent_feature __cpuinitconst
290 cpuid_dependent_features[] = {
291 	{ X86_FEATURE_MWAIT,		0x00000005 },
292 	{ X86_FEATURE_DCA,		0x00000009 },
293 	{ X86_FEATURE_XSAVE,		0x0000000d },
294 	{ 0, 0 }
295 };
296 
297 static void __cpuinit filter_cpuid_features(struct cpuinfo_x86 *c, bool warn)
298 {
299 	const struct cpuid_dependent_feature *df;
300 
301 	for (df = cpuid_dependent_features; df->feature; df++) {
302 
303 		if (!cpu_has(c, df->feature))
304 			continue;
305 		/*
306 		 * Note: cpuid_level is set to -1 if unavailable, but
307 		 * extended_extended_level is set to 0 if unavailable
308 		 * and the legitimate extended levels are all negative
309 		 * when signed; hence the weird messing around with
310 		 * signs here...
311 		 */
312 		if (!((s32)df->level < 0 ?
313 		     (u32)df->level > (u32)c->extended_cpuid_level :
314 		     (s32)df->level > (s32)c->cpuid_level))
315 			continue;
316 
317 		clear_cpu_cap(c, df->feature);
318 		if (!warn)
319 			continue;
320 
321 		printk(KERN_WARNING
322 		       "CPU: CPU feature %s disabled, no CPUID level 0x%x\n",
323 				x86_cap_flags[df->feature], df->level);
324 	}
325 }
326 
327 /*
328  * Naming convention should be: <Name> [(<Codename>)]
329  * This table only is used unless init_<vendor>() below doesn't set it;
330  * in particular, if CPUID levels 0x80000002..4 are supported, this
331  * isn't used
332  */
333 
334 /* Look up CPU names by table lookup. */
335 static const char *__cpuinit table_lookup_model(struct cpuinfo_x86 *c)
336 {
337 	const struct cpu_model_info *info;
338 
339 	if (c->x86_model >= 16)
340 		return NULL;	/* Range check */
341 
342 	if (!this_cpu)
343 		return NULL;
344 
345 	info = this_cpu->c_models;
346 
347 	while (info && info->family) {
348 		if (info->family == c->x86)
349 			return info->model_names[c->x86_model];
350 		info++;
351 	}
352 	return NULL;		/* Not found */
353 }
354 
355 __u32 cpu_caps_cleared[NCAPINTS] __cpuinitdata;
356 __u32 cpu_caps_set[NCAPINTS] __cpuinitdata;
357 
358 void load_percpu_segment(int cpu)
359 {
360 #ifdef CONFIG_X86_32
361 	loadsegment(fs, __KERNEL_PERCPU);
362 #else
363 	loadsegment(gs, 0);
364 	wrmsrl(MSR_GS_BASE, (unsigned long)per_cpu(irq_stack_union.gs_base, cpu));
365 #endif
366 	load_stack_canary_segment();
367 }
368 
369 /*
370  * Current gdt points %fs at the "master" per-cpu area: after this,
371  * it's on the real one.
372  */
373 void switch_to_new_gdt(int cpu)
374 {
375 	struct desc_ptr gdt_descr;
376 
377 	gdt_descr.address = (long)get_cpu_gdt_table(cpu);
378 	gdt_descr.size = GDT_SIZE - 1;
379 	load_gdt(&gdt_descr);
380 	/* Reload the per-cpu base */
381 
382 	load_percpu_segment(cpu);
383 }
384 
385 static const struct cpu_dev *__cpuinitdata cpu_devs[X86_VENDOR_NUM] = {};
386 
387 static void __cpuinit get_model_name(struct cpuinfo_x86 *c)
388 {
389 	unsigned int *v;
390 	char *p, *q;
391 
392 	if (c->extended_cpuid_level < 0x80000004)
393 		return;
394 
395 	v = (unsigned int *)c->x86_model_id;
396 	cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
397 	cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
398 	cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
399 	c->x86_model_id[48] = 0;
400 
401 	/*
402 	 * Intel chips right-justify this string for some dumb reason;
403 	 * undo that brain damage:
404 	 */
405 	p = q = &c->x86_model_id[0];
406 	while (*p == ' ')
407 		p++;
408 	if (p != q) {
409 		while (*p)
410 			*q++ = *p++;
411 		while (q <= &c->x86_model_id[48])
412 			*q++ = '\0';	/* Zero-pad the rest */
413 	}
414 }
415 
416 void __cpuinit cpu_detect_cache_sizes(struct cpuinfo_x86 *c)
417 {
418 	unsigned int n, dummy, ebx, ecx, edx, l2size;
419 
420 	n = c->extended_cpuid_level;
421 
422 	if (n >= 0x80000005) {
423 		cpuid(0x80000005, &dummy, &ebx, &ecx, &edx);
424 		c->x86_cache_size = (ecx>>24) + (edx>>24);
425 #ifdef CONFIG_X86_64
426 		/* On K8 L1 TLB is inclusive, so don't count it */
427 		c->x86_tlbsize = 0;
428 #endif
429 	}
430 
431 	if (n < 0x80000006)	/* Some chips just has a large L1. */
432 		return;
433 
434 	cpuid(0x80000006, &dummy, &ebx, &ecx, &edx);
435 	l2size = ecx >> 16;
436 
437 #ifdef CONFIG_X86_64
438 	c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff);
439 #else
440 	/* do processor-specific cache resizing */
441 	if (this_cpu->c_size_cache)
442 		l2size = this_cpu->c_size_cache(c, l2size);
443 
444 	/* Allow user to override all this if necessary. */
445 	if (cachesize_override != -1)
446 		l2size = cachesize_override;
447 
448 	if (l2size == 0)
449 		return;		/* Again, no L2 cache is possible */
450 #endif
451 
452 	c->x86_cache_size = l2size;
453 }
454 
455 void __cpuinit detect_ht(struct cpuinfo_x86 *c)
456 {
457 #ifdef CONFIG_X86_HT
458 	u32 eax, ebx, ecx, edx;
459 	int index_msb, core_bits;
460 	static bool printed;
461 
462 	if (!cpu_has(c, X86_FEATURE_HT))
463 		return;
464 
465 	if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
466 		goto out;
467 
468 	if (cpu_has(c, X86_FEATURE_XTOPOLOGY))
469 		return;
470 
471 	cpuid(1, &eax, &ebx, &ecx, &edx);
472 
473 	smp_num_siblings = (ebx & 0xff0000) >> 16;
474 
475 	if (smp_num_siblings == 1) {
476 		printk_once(KERN_INFO "CPU0: Hyper-Threading is disabled\n");
477 		goto out;
478 	}
479 
480 	if (smp_num_siblings <= 1)
481 		goto out;
482 
483 	index_msb = get_count_order(smp_num_siblings);
484 	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);
485 
486 	smp_num_siblings = smp_num_siblings / c->x86_max_cores;
487 
488 	index_msb = get_count_order(smp_num_siblings);
489 
490 	core_bits = get_count_order(c->x86_max_cores);
491 
492 	c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, index_msb) &
493 				       ((1 << core_bits) - 1);
494 
495 out:
496 	if (!printed && (c->x86_max_cores * smp_num_siblings) > 1) {
497 		printk(KERN_INFO  "CPU: Physical Processor ID: %d\n",
498 		       c->phys_proc_id);
499 		printk(KERN_INFO  "CPU: Processor Core ID: %d\n",
500 		       c->cpu_core_id);
501 		printed = 1;
502 	}
503 #endif
504 }
505 
506 static void __cpuinit get_cpu_vendor(struct cpuinfo_x86 *c)
507 {
508 	char *v = c->x86_vendor_id;
509 	int i;
510 
511 	for (i = 0; i < X86_VENDOR_NUM; i++) {
512 		if (!cpu_devs[i])
513 			break;
514 
515 		if (!strcmp(v, cpu_devs[i]->c_ident[0]) ||
516 		    (cpu_devs[i]->c_ident[1] &&
517 		     !strcmp(v, cpu_devs[i]->c_ident[1]))) {
518 
519 			this_cpu = cpu_devs[i];
520 			c->x86_vendor = this_cpu->c_x86_vendor;
521 			return;
522 		}
523 	}
524 
525 	printk_once(KERN_ERR
526 			"CPU: vendor_id '%s' unknown, using generic init.\n" \
527 			"CPU: Your system may be unstable.\n", v);
528 
529 	c->x86_vendor = X86_VENDOR_UNKNOWN;
530 	this_cpu = &default_cpu;
531 }
532 
533 void __cpuinit cpu_detect(struct cpuinfo_x86 *c)
534 {
535 	/* Get vendor name */
536 	cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
537 	      (unsigned int *)&c->x86_vendor_id[0],
538 	      (unsigned int *)&c->x86_vendor_id[8],
539 	      (unsigned int *)&c->x86_vendor_id[4]);
540 
541 	c->x86 = 4;
542 	/* Intel-defined flags: level 0x00000001 */
543 	if (c->cpuid_level >= 0x00000001) {
544 		u32 junk, tfms, cap0, misc;
545 
546 		cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
547 		c->x86 = (tfms >> 8) & 0xf;
548 		c->x86_model = (tfms >> 4) & 0xf;
549 		c->x86_mask = tfms & 0xf;
550 
551 		if (c->x86 == 0xf)
552 			c->x86 += (tfms >> 20) & 0xff;
553 		if (c->x86 >= 0x6)
554 			c->x86_model += ((tfms >> 16) & 0xf) << 4;
555 
556 		if (cap0 & (1<<19)) {
557 			c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
558 			c->x86_cache_alignment = c->x86_clflush_size;
559 		}
560 	}
561 }
562 
563 void __cpuinit get_cpu_cap(struct cpuinfo_x86 *c)
564 {
565 	u32 tfms, xlvl;
566 	u32 ebx;
567 
568 	/* Intel-defined flags: level 0x00000001 */
569 	if (c->cpuid_level >= 0x00000001) {
570 		u32 capability, excap;
571 
572 		cpuid(0x00000001, &tfms, &ebx, &excap, &capability);
573 		c->x86_capability[0] = capability;
574 		c->x86_capability[4] = excap;
575 	}
576 
577 	/* Additional Intel-defined flags: level 0x00000007 */
578 	if (c->cpuid_level >= 0x00000007) {
579 		u32 eax, ebx, ecx, edx;
580 
581 		cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx);
582 
583 		c->x86_capability[9] = ebx;
584 	}
585 
586 	/* AMD-defined flags: level 0x80000001 */
587 	xlvl = cpuid_eax(0x80000000);
588 	c->extended_cpuid_level = xlvl;
589 
590 	if ((xlvl & 0xffff0000) == 0x80000000) {
591 		if (xlvl >= 0x80000001) {
592 			c->x86_capability[1] = cpuid_edx(0x80000001);
593 			c->x86_capability[6] = cpuid_ecx(0x80000001);
594 		}
595 	}
596 
597 	if (c->extended_cpuid_level >= 0x80000008) {
598 		u32 eax = cpuid_eax(0x80000008);
599 
600 		c->x86_virt_bits = (eax >> 8) & 0xff;
601 		c->x86_phys_bits = eax & 0xff;
602 	}
603 #ifdef CONFIG_X86_32
604 	else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36))
605 		c->x86_phys_bits = 36;
606 #endif
607 
608 	if (c->extended_cpuid_level >= 0x80000007)
609 		c->x86_power = cpuid_edx(0x80000007);
610 
611 	init_scattered_cpuid_features(c);
612 }
613 
614 static void __cpuinit identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
615 {
616 #ifdef CONFIG_X86_32
617 	int i;
618 
619 	/*
620 	 * First of all, decide if this is a 486 or higher
621 	 * It's a 486 if we can modify the AC flag
622 	 */
623 	if (flag_is_changeable_p(X86_EFLAGS_AC))
624 		c->x86 = 4;
625 	else
626 		c->x86 = 3;
627 
628 	for (i = 0; i < X86_VENDOR_NUM; i++)
629 		if (cpu_devs[i] && cpu_devs[i]->c_identify) {
630 			c->x86_vendor_id[0] = 0;
631 			cpu_devs[i]->c_identify(c);
632 			if (c->x86_vendor_id[0]) {
633 				get_cpu_vendor(c);
634 				break;
635 			}
636 		}
637 #endif
638 }
639 
640 /*
641  * Do minimum CPU detection early.
642  * Fields really needed: vendor, cpuid_level, family, model, mask,
643  * cache alignment.
644  * The others are not touched to avoid unwanted side effects.
645  *
646  * WARNING: this function is only called on the BP.  Don't add code here
647  * that is supposed to run on all CPUs.
648  */
649 static void __init early_identify_cpu(struct cpuinfo_x86 *c)
650 {
651 #ifdef CONFIG_X86_64
652 	c->x86_clflush_size = 64;
653 	c->x86_phys_bits = 36;
654 	c->x86_virt_bits = 48;
655 #else
656 	c->x86_clflush_size = 32;
657 	c->x86_phys_bits = 32;
658 	c->x86_virt_bits = 32;
659 #endif
660 	c->x86_cache_alignment = c->x86_clflush_size;
661 
662 	memset(&c->x86_capability, 0, sizeof c->x86_capability);
663 	c->extended_cpuid_level = 0;
664 
665 	if (!have_cpuid_p())
666 		identify_cpu_without_cpuid(c);
667 
668 	/* cyrix could have cpuid enabled via c_identify()*/
669 	if (!have_cpuid_p())
670 		return;
671 
672 	cpu_detect(c);
673 
674 	get_cpu_vendor(c);
675 
676 	get_cpu_cap(c);
677 
678 	if (this_cpu->c_early_init)
679 		this_cpu->c_early_init(c);
680 
681 	c->cpu_index = 0;
682 	filter_cpuid_features(c, false);
683 
684 	setup_smep(c);
685 
686 	if (this_cpu->c_bsp_init)
687 		this_cpu->c_bsp_init(c);
688 }
689 
690 void __init early_cpu_init(void)
691 {
692 	const struct cpu_dev *const *cdev;
693 	int count = 0;
694 
695 #ifdef CONFIG_PROCESSOR_SELECT
696 	printk(KERN_INFO "KERNEL supported cpus:\n");
697 #endif
698 
699 	for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) {
700 		const struct cpu_dev *cpudev = *cdev;
701 
702 		if (count >= X86_VENDOR_NUM)
703 			break;
704 		cpu_devs[count] = cpudev;
705 		count++;
706 
707 #ifdef CONFIG_PROCESSOR_SELECT
708 		{
709 			unsigned int j;
710 
711 			for (j = 0; j < 2; j++) {
712 				if (!cpudev->c_ident[j])
713 					continue;
714 				printk(KERN_INFO "  %s %s\n", cpudev->c_vendor,
715 					cpudev->c_ident[j]);
716 			}
717 		}
718 #endif
719 	}
720 	early_identify_cpu(&boot_cpu_data);
721 }
722 
723 /*
724  * The NOPL instruction is supposed to exist on all CPUs of family >= 6;
725  * unfortunately, that's not true in practice because of early VIA
726  * chips and (more importantly) broken virtualizers that are not easy
727  * to detect. In the latter case it doesn't even *fail* reliably, so
728  * probing for it doesn't even work. Disable it completely on 32-bit
729  * unless we can find a reliable way to detect all the broken cases.
730  * Enable it explicitly on 64-bit for non-constant inputs of cpu_has().
731  */
732 static void __cpuinit detect_nopl(struct cpuinfo_x86 *c)
733 {
734 #ifdef CONFIG_X86_32
735 	clear_cpu_cap(c, X86_FEATURE_NOPL);
736 #else
737 	set_cpu_cap(c, X86_FEATURE_NOPL);
738 #endif
739 }
740 
741 static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
742 {
743 	c->extended_cpuid_level = 0;
744 
745 	if (!have_cpuid_p())
746 		identify_cpu_without_cpuid(c);
747 
748 	/* cyrix could have cpuid enabled via c_identify()*/
749 	if (!have_cpuid_p())
750 		return;
751 
752 	cpu_detect(c);
753 
754 	get_cpu_vendor(c);
755 
756 	get_cpu_cap(c);
757 
758 	if (c->cpuid_level >= 0x00000001) {
759 		c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF;
760 #ifdef CONFIG_X86_32
761 # ifdef CONFIG_X86_HT
762 		c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
763 # else
764 		c->apicid = c->initial_apicid;
765 # endif
766 #endif
767 		c->phys_proc_id = c->initial_apicid;
768 	}
769 
770 	setup_smep(c);
771 
772 	get_model_name(c); /* Default name */
773 
774 	detect_nopl(c);
775 }
776 
777 /*
778  * This does the hard work of actually picking apart the CPU stuff...
779  */
780 static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
781 {
782 	int i;
783 
784 	c->loops_per_jiffy = loops_per_jiffy;
785 	c->x86_cache_size = -1;
786 	c->x86_vendor = X86_VENDOR_UNKNOWN;
787 	c->x86_model = c->x86_mask = 0;	/* So far unknown... */
788 	c->x86_vendor_id[0] = '\0'; /* Unset */
789 	c->x86_model_id[0] = '\0';  /* Unset */
790 	c->x86_max_cores = 1;
791 	c->x86_coreid_bits = 0;
792 #ifdef CONFIG_X86_64
793 	c->x86_clflush_size = 64;
794 	c->x86_phys_bits = 36;
795 	c->x86_virt_bits = 48;
796 #else
797 	c->cpuid_level = -1;	/* CPUID not detected */
798 	c->x86_clflush_size = 32;
799 	c->x86_phys_bits = 32;
800 	c->x86_virt_bits = 32;
801 #endif
802 	c->x86_cache_alignment = c->x86_clflush_size;
803 	memset(&c->x86_capability, 0, sizeof c->x86_capability);
804 
805 	generic_identify(c);
806 
807 	if (this_cpu->c_identify)
808 		this_cpu->c_identify(c);
809 
810 	/* Clear/Set all flags overriden by options, after probe */
811 	for (i = 0; i < NCAPINTS; i++) {
812 		c->x86_capability[i] &= ~cpu_caps_cleared[i];
813 		c->x86_capability[i] |= cpu_caps_set[i];
814 	}
815 
816 #ifdef CONFIG_X86_64
817 	c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
818 #endif
819 
820 	/*
821 	 * Vendor-specific initialization.  In this section we
822 	 * canonicalize the feature flags, meaning if there are
823 	 * features a certain CPU supports which CPUID doesn't
824 	 * tell us, CPUID claiming incorrect flags, or other bugs,
825 	 * we handle them here.
826 	 *
827 	 * At the end of this section, c->x86_capability better
828 	 * indicate the features this CPU genuinely supports!
829 	 */
830 	if (this_cpu->c_init)
831 		this_cpu->c_init(c);
832 
833 	/* Disable the PN if appropriate */
834 	squash_the_stupid_serial_number(c);
835 
836 	/*
837 	 * The vendor-specific functions might have changed features.
838 	 * Now we do "generic changes."
839 	 */
840 
841 	/* Filter out anything that depends on CPUID levels we don't have */
842 	filter_cpuid_features(c, true);
843 
844 	/* If the model name is still unset, do table lookup. */
845 	if (!c->x86_model_id[0]) {
846 		const char *p;
847 		p = table_lookup_model(c);
848 		if (p)
849 			strcpy(c->x86_model_id, p);
850 		else
851 			/* Last resort... */
852 			sprintf(c->x86_model_id, "%02x/%02x",
853 				c->x86, c->x86_model);
854 	}
855 
856 #ifdef CONFIG_X86_64
857 	detect_ht(c);
858 #endif
859 
860 	init_hypervisor(c);
861 	x86_init_rdrand(c);
862 
863 	/*
864 	 * Clear/Set all flags overriden by options, need do it
865 	 * before following smp all cpus cap AND.
866 	 */
867 	for (i = 0; i < NCAPINTS; i++) {
868 		c->x86_capability[i] &= ~cpu_caps_cleared[i];
869 		c->x86_capability[i] |= cpu_caps_set[i];
870 	}
871 
872 	/*
873 	 * On SMP, boot_cpu_data holds the common feature set between
874 	 * all CPUs; so make sure that we indicate which features are
875 	 * common between the CPUs.  The first time this routine gets
876 	 * executed, c == &boot_cpu_data.
877 	 */
878 	if (c != &boot_cpu_data) {
879 		/* AND the already accumulated flags with these */
880 		for (i = 0; i < NCAPINTS; i++)
881 			boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
882 	}
883 
884 	/* Init Machine Check Exception if available. */
885 	mcheck_cpu_init(c);
886 
887 	select_idle_routine(c);
888 
889 #ifdef CONFIG_NUMA
890 	numa_add_cpu(smp_processor_id());
891 #endif
892 }
893 
894 #ifdef CONFIG_X86_64
895 static void vgetcpu_set_mode(void)
896 {
897 	if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))
898 		vgetcpu_mode = VGETCPU_RDTSCP;
899 	else
900 		vgetcpu_mode = VGETCPU_LSL;
901 }
902 #endif
903 
904 void __init identify_boot_cpu(void)
905 {
906 	identify_cpu(&boot_cpu_data);
907 	init_amd_e400_c1e_mask();
908 #ifdef CONFIG_X86_32
909 	sysenter_setup();
910 	enable_sep_cpu();
911 #else
912 	vgetcpu_set_mode();
913 #endif
914 }
915 
916 void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
917 {
918 	BUG_ON(c == &boot_cpu_data);
919 	identify_cpu(c);
920 #ifdef CONFIG_X86_32
921 	enable_sep_cpu();
922 #endif
923 	mtrr_ap_init();
924 }
925 
926 struct msr_range {
927 	unsigned	min;
928 	unsigned	max;
929 };
930 
931 static const struct msr_range msr_range_array[] __cpuinitconst = {
932 	{ 0x00000000, 0x00000418},
933 	{ 0xc0000000, 0xc000040b},
934 	{ 0xc0010000, 0xc0010142},
935 	{ 0xc0011000, 0xc001103b},
936 };
937 
938 static void __cpuinit __print_cpu_msr(void)
939 {
940 	unsigned index_min, index_max;
941 	unsigned index;
942 	u64 val;
943 	int i;
944 
945 	for (i = 0; i < ARRAY_SIZE(msr_range_array); i++) {
946 		index_min = msr_range_array[i].min;
947 		index_max = msr_range_array[i].max;
948 
949 		for (index = index_min; index < index_max; index++) {
950 			if (rdmsrl_amd_safe(index, &val))
951 				continue;
952 			printk(KERN_INFO " MSR%08x: %016llx\n", index, val);
953 		}
954 	}
955 }
956 
957 static int show_msr __cpuinitdata;
958 
959 static __init int setup_show_msr(char *arg)
960 {
961 	int num;
962 
963 	get_option(&arg, &num);
964 
965 	if (num > 0)
966 		show_msr = num;
967 	return 1;
968 }
969 __setup("show_msr=", setup_show_msr);
970 
971 static __init int setup_noclflush(char *arg)
972 {
973 	setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
974 	return 1;
975 }
976 __setup("noclflush", setup_noclflush);
977 
978 void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
979 {
980 	const char *vendor = NULL;
981 
982 	if (c->x86_vendor < X86_VENDOR_NUM) {
983 		vendor = this_cpu->c_vendor;
984 	} else {
985 		if (c->cpuid_level >= 0)
986 			vendor = c->x86_vendor_id;
987 	}
988 
989 	if (vendor && !strstr(c->x86_model_id, vendor))
990 		printk(KERN_CONT "%s ", vendor);
991 
992 	if (c->x86_model_id[0])
993 		printk(KERN_CONT "%s", c->x86_model_id);
994 	else
995 		printk(KERN_CONT "%d86", c->x86);
996 
997 	if (c->x86_mask || c->cpuid_level >= 0)
998 		printk(KERN_CONT " stepping %02x\n", c->x86_mask);
999 	else
1000 		printk(KERN_CONT "\n");
1001 
1002 	__print_cpu_msr();
1003 }
1004 
1005 void __cpuinit print_cpu_msr(struct cpuinfo_x86 *c)
1006 {
1007 	if (c->cpu_index < show_msr)
1008 		__print_cpu_msr();
1009 }
1010 
1011 static __init int setup_disablecpuid(char *arg)
1012 {
1013 	int bit;
1014 
1015 	if (get_option(&arg, &bit) && bit < NCAPINTS*32)
1016 		setup_clear_cpu_cap(bit);
1017 	else
1018 		return 0;
1019 
1020 	return 1;
1021 }
1022 __setup("clearcpuid=", setup_disablecpuid);
1023 
1024 #ifdef CONFIG_X86_64
1025 struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
1026 struct desc_ptr nmi_idt_descr = { NR_VECTORS * 16 - 1,
1027 				    (unsigned long) nmi_idt_table };
1028 
1029 DEFINE_PER_CPU_FIRST(union irq_stack_union,
1030 		     irq_stack_union) __aligned(PAGE_SIZE);
1031 
1032 /*
1033  * The following four percpu variables are hot.  Align current_task to
1034  * cacheline size such that all four fall in the same cacheline.
1035  */
1036 DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
1037 	&init_task;
1038 EXPORT_PER_CPU_SYMBOL(current_task);
1039 
1040 DEFINE_PER_CPU(unsigned long, kernel_stack) =
1041 	(unsigned long)&init_thread_union - KERNEL_STACK_OFFSET + THREAD_SIZE;
1042 EXPORT_PER_CPU_SYMBOL(kernel_stack);
1043 
1044 DEFINE_PER_CPU(char *, irq_stack_ptr) =
1045 	init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64;
1046 
1047 DEFINE_PER_CPU(unsigned int, irq_count) = -1;
1048 
1049 DEFINE_PER_CPU(struct task_struct *, fpu_owner_task);
1050 
1051 /*
1052  * Special IST stacks which the CPU switches to when it calls
1053  * an IST-marked descriptor entry. Up to 7 stacks (hardware
1054  * limit), all of them are 4K, except the debug stack which
1055  * is 8K.
1056  */
1057 static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
1058 	  [0 ... N_EXCEPTION_STACKS - 1]	= EXCEPTION_STKSZ,
1059 	  [DEBUG_STACK - 1]			= DEBUG_STKSZ
1060 };
1061 
1062 static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
1063 	[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
1064 
1065 /* May not be marked __init: used by software suspend */
1066 void syscall_init(void)
1067 {
1068 	/*
1069 	 * LSTAR and STAR live in a bit strange symbiosis.
1070 	 * They both write to the same internal register. STAR allows to
1071 	 * set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
1072 	 */
1073 	wrmsrl(MSR_STAR,  ((u64)__USER32_CS)<<48  | ((u64)__KERNEL_CS)<<32);
1074 	wrmsrl(MSR_LSTAR, system_call);
1075 	wrmsrl(MSR_CSTAR, ignore_sysret);
1076 
1077 #ifdef CONFIG_IA32_EMULATION
1078 	syscall32_cpu_init();
1079 #endif
1080 
1081 	/* Flags to clear on syscall */
1082 	wrmsrl(MSR_SYSCALL_MASK,
1083 	       X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF|X86_EFLAGS_IOPL);
1084 }
1085 
1086 unsigned long kernel_eflags;
1087 
1088 /*
1089  * Copies of the original ist values from the tss are only accessed during
1090  * debugging, no special alignment required.
1091  */
1092 DEFINE_PER_CPU(struct orig_ist, orig_ist);
1093 
1094 static DEFINE_PER_CPU(unsigned long, debug_stack_addr);
1095 DEFINE_PER_CPU(int, debug_stack_usage);
1096 
1097 int is_debug_stack(unsigned long addr)
1098 {
1099 	return __get_cpu_var(debug_stack_usage) ||
1100 		(addr <= __get_cpu_var(debug_stack_addr) &&
1101 		 addr > (__get_cpu_var(debug_stack_addr) - DEBUG_STKSZ));
1102 }
1103 
1104 void debug_stack_set_zero(void)
1105 {
1106 	load_idt((const struct desc_ptr *)&nmi_idt_descr);
1107 }
1108 
1109 void debug_stack_reset(void)
1110 {
1111 	load_idt((const struct desc_ptr *)&idt_descr);
1112 }
1113 
1114 #else	/* CONFIG_X86_64 */
1115 
1116 DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
1117 EXPORT_PER_CPU_SYMBOL(current_task);
1118 DEFINE_PER_CPU(struct task_struct *, fpu_owner_task);
1119 
1120 #ifdef CONFIG_CC_STACKPROTECTOR
1121 DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary);
1122 #endif
1123 
1124 /* Make sure %fs and %gs are initialized properly in idle threads */
1125 struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
1126 {
1127 	memset(regs, 0, sizeof(struct pt_regs));
1128 	regs->fs = __KERNEL_PERCPU;
1129 	regs->gs = __KERNEL_STACK_CANARY;
1130 
1131 	return regs;
1132 }
1133 #endif	/* CONFIG_X86_64 */
1134 
1135 /*
1136  * Clear all 6 debug registers:
1137  */
1138 static void clear_all_debug_regs(void)
1139 {
1140 	int i;
1141 
1142 	for (i = 0; i < 8; i++) {
1143 		/* Ignore db4, db5 */
1144 		if ((i == 4) || (i == 5))
1145 			continue;
1146 
1147 		set_debugreg(0, i);
1148 	}
1149 }
1150 
1151 #ifdef CONFIG_KGDB
1152 /*
1153  * Restore debug regs if using kgdbwait and you have a kernel debugger
1154  * connection established.
1155  */
1156 static void dbg_restore_debug_regs(void)
1157 {
1158 	if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break))
1159 		arch_kgdb_ops.correct_hw_break();
1160 }
1161 #else /* ! CONFIG_KGDB */
1162 #define dbg_restore_debug_regs()
1163 #endif /* ! CONFIG_KGDB */
1164 
1165 /*
1166  * Prints an error where the NUMA and configured core-number mismatch and the
1167  * platform didn't override this to fix it up
1168  */
1169 void __cpuinit x86_default_fixup_cpu_id(struct cpuinfo_x86 *c, int node)
1170 {
1171 	pr_err("NUMA core number %d differs from configured core number %d\n", node, c->phys_proc_id);
1172 }
1173 
1174 /*
1175  * cpu_init() initializes state that is per-CPU. Some data is already
1176  * initialized (naturally) in the bootstrap process, such as the GDT
1177  * and IDT. We reload them nevertheless, this function acts as a
1178  * 'CPU state barrier', nothing should get across.
1179  * A lot of state is already set up in PDA init for 64 bit
1180  */
1181 #ifdef CONFIG_X86_64
1182 
1183 void __cpuinit cpu_init(void)
1184 {
1185 	struct orig_ist *oist;
1186 	struct task_struct *me;
1187 	struct tss_struct *t;
1188 	unsigned long v;
1189 	int cpu;
1190 	int i;
1191 
1192 	cpu = stack_smp_processor_id();
1193 	t = &per_cpu(init_tss, cpu);
1194 	oist = &per_cpu(orig_ist, cpu);
1195 
1196 #ifdef CONFIG_NUMA
1197 	if (cpu != 0 && percpu_read(numa_node) == 0 &&
1198 	    early_cpu_to_node(cpu) != NUMA_NO_NODE)
1199 		set_numa_node(early_cpu_to_node(cpu));
1200 #endif
1201 
1202 	me = current;
1203 
1204 	if (cpumask_test_and_set_cpu(cpu, cpu_initialized_mask))
1205 		panic("CPU#%d already initialized!\n", cpu);
1206 
1207 	pr_debug("Initializing CPU#%d\n", cpu);
1208 
1209 	clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
1210 
1211 	/*
1212 	 * Initialize the per-CPU GDT with the boot GDT,
1213 	 * and set up the GDT descriptor:
1214 	 */
1215 
1216 	switch_to_new_gdt(cpu);
1217 	loadsegment(fs, 0);
1218 
1219 	load_idt((const struct desc_ptr *)&idt_descr);
1220 
1221 	memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);
1222 	syscall_init();
1223 
1224 	wrmsrl(MSR_FS_BASE, 0);
1225 	wrmsrl(MSR_KERNEL_GS_BASE, 0);
1226 	barrier();
1227 
1228 	x86_configure_nx();
1229 	if (cpu != 0)
1230 		enable_x2apic();
1231 
1232 	/*
1233 	 * set up and load the per-CPU TSS
1234 	 */
1235 	if (!oist->ist[0]) {
1236 		char *estacks = per_cpu(exception_stacks, cpu);
1237 
1238 		for (v = 0; v < N_EXCEPTION_STACKS; v++) {
1239 			estacks += exception_stack_sizes[v];
1240 			oist->ist[v] = t->x86_tss.ist[v] =
1241 					(unsigned long)estacks;
1242 			if (v == DEBUG_STACK-1)
1243 				per_cpu(debug_stack_addr, cpu) = (unsigned long)estacks;
1244 		}
1245 	}
1246 
1247 	t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
1248 
1249 	/*
1250 	 * <= is required because the CPU will access up to
1251 	 * 8 bits beyond the end of the IO permission bitmap.
1252 	 */
1253 	for (i = 0; i <= IO_BITMAP_LONGS; i++)
1254 		t->io_bitmap[i] = ~0UL;
1255 
1256 	atomic_inc(&init_mm.mm_count);
1257 	me->active_mm = &init_mm;
1258 	BUG_ON(me->mm);
1259 	enter_lazy_tlb(&init_mm, me);
1260 
1261 	load_sp0(t, &current->thread);
1262 	set_tss_desc(cpu, t);
1263 	load_TR_desc();
1264 	load_LDT(&init_mm.context);
1265 
1266 	clear_all_debug_regs();
1267 	dbg_restore_debug_regs();
1268 
1269 	fpu_init();
1270 	xsave_init();
1271 
1272 	raw_local_save_flags(kernel_eflags);
1273 
1274 	if (is_uv_system())
1275 		uv_cpu_init();
1276 }
1277 
1278 #else
1279 
1280 void __cpuinit cpu_init(void)
1281 {
1282 	int cpu = smp_processor_id();
1283 	struct task_struct *curr = current;
1284 	struct tss_struct *t = &per_cpu(init_tss, cpu);
1285 	struct thread_struct *thread = &curr->thread;
1286 
1287 	if (cpumask_test_and_set_cpu(cpu, cpu_initialized_mask)) {
1288 		printk(KERN_WARNING "CPU#%d already initialized!\n", cpu);
1289 		for (;;)
1290 			local_irq_enable();
1291 	}
1292 
1293 	printk(KERN_INFO "Initializing CPU#%d\n", cpu);
1294 
1295 	if (cpu_has_vme || cpu_has_tsc || cpu_has_de)
1296 		clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
1297 
1298 	load_idt(&idt_descr);
1299 	switch_to_new_gdt(cpu);
1300 
1301 	/*
1302 	 * Set up and load the per-CPU TSS and LDT
1303 	 */
1304 	atomic_inc(&init_mm.mm_count);
1305 	curr->active_mm = &init_mm;
1306 	BUG_ON(curr->mm);
1307 	enter_lazy_tlb(&init_mm, curr);
1308 
1309 	load_sp0(t, thread);
1310 	set_tss_desc(cpu, t);
1311 	load_TR_desc();
1312 	load_LDT(&init_mm.context);
1313 
1314 	t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
1315 
1316 #ifdef CONFIG_DOUBLEFAULT
1317 	/* Set up doublefault TSS pointer in the GDT */
1318 	__set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
1319 #endif
1320 
1321 	clear_all_debug_regs();
1322 	dbg_restore_debug_regs();
1323 
1324 	fpu_init();
1325 	xsave_init();
1326 }
1327 #endif
1328