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   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() */
  48cpumask_var_t cpu_initialized_mask;
  49cpumask_var_t cpu_callout_mask;
  50cpumask_var_t cpu_callin_mask;
  51
  52/* representing cpus for which sibling maps can be computed */
  53cpumask_var_t cpu_sibling_setup_mask;
  54
  55/* correctly size the local cpu masks */
  56void __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
  64static 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
  81static 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
  87static const struct cpu_dev *this_cpu __cpuinitdata = &default_cpu;
  88
  89DEFINE_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} };
 141EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
 142
 143static 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	setup_clear_cpu_cap(X86_FEATURE_AVX);
 148	setup_clear_cpu_cap(X86_FEATURE_AVX2);
 149	return 1;
 150}
 151__setup("noxsave", x86_xsave_setup);
 152
 153static int __init x86_xsaveopt_setup(char *s)
 154{
 155	setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);
 156	return 1;
 157}
 158__setup("noxsaveopt", x86_xsaveopt_setup);
 159
 160#ifdef CONFIG_X86_32
 161static int cachesize_override __cpuinitdata = -1;
 162static int disable_x86_serial_nr __cpuinitdata = 1;
 163
 164static int __init cachesize_setup(char *str)
 165{
 166	get_option(&str, &cachesize_override);
 167	return 1;
 168}
 169__setup("cachesize=", cachesize_setup);
 170
 171static int __init x86_fxsr_setup(char *s)
 172{
 173	setup_clear_cpu_cap(X86_FEATURE_FXSR);
 174	setup_clear_cpu_cap(X86_FEATURE_XMM);
 175	return 1;
 176}
 177__setup("nofxsr", x86_fxsr_setup);
 178
 179static int __init x86_sep_setup(char *s)
 180{
 181	setup_clear_cpu_cap(X86_FEATURE_SEP);
 182	return 1;
 183}
 184__setup("nosep", x86_sep_setup);
 185
 186/* Standard macro to see if a specific flag is changeable */
 187static inline int flag_is_changeable_p(u32 flag)
 188{
 189	u32 f1, f2;
 190
 191	/*
 192	 * Cyrix and IDT cpus allow disabling of CPUID
 193	 * so the code below may return different results
 194	 * when it is executed before and after enabling
 195	 * the CPUID. Add "volatile" to not allow gcc to
 196	 * optimize the subsequent calls to this function.
 197	 */
 198	asm volatile ("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
 209		      : "=&r" (f1), "=&r" (f2)
 210		      : "ir" (flag));
 211
 212	return ((f1^f2) & flag) != 0;
 213}
 214
 215/* Probe for the CPUID instruction */
 216static int __cpuinit have_cpuid_p(void)
 217{
 218	return flag_is_changeable_p(X86_EFLAGS_ID);
 219}
 220
 221static void __cpuinit squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
 222{
 223	unsigned long lo, hi;
 224
 225	if (!cpu_has(c, X86_FEATURE_PN) || !disable_x86_serial_nr)
 226		return;
 227
 228	/* Disable processor serial number: */
 229
 230	rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
 231	lo |= 0x200000;
 232	wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
 233
 234	printk(KERN_NOTICE "CPU serial number disabled.\n");
 235	clear_cpu_cap(c, X86_FEATURE_PN);
 236
 237	/* Disabling the serial number may affect the cpuid level */
 238	c->cpuid_level = cpuid_eax(0);
 239}
 240
 241static int __init x86_serial_nr_setup(char *s)
 242{
 243	disable_x86_serial_nr = 0;
 244	return 1;
 245}
 246__setup("serialnumber", x86_serial_nr_setup);
 247#else
 248static inline int flag_is_changeable_p(u32 flag)
 249{
 250	return 1;
 251}
 252/* Probe for the CPUID instruction */
 253static inline int have_cpuid_p(void)
 254{
 255	return 1;
 256}
 257static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
 258{
 259}
 260#endif
 261
 262static int disable_smep __cpuinitdata;
 263static __init int setup_disable_smep(char *arg)
 264{
 265	disable_smep = 1;
 266	return 1;
 267}
 268__setup("nosmep", setup_disable_smep);
 269
 270static __cpuinit void setup_smep(struct cpuinfo_x86 *c)
 271{
 272	if (cpu_has(c, X86_FEATURE_SMEP)) {
 273		if (unlikely(disable_smep)) {
 274			setup_clear_cpu_cap(X86_FEATURE_SMEP);
 275			clear_in_cr4(X86_CR4_SMEP);
 276		} else
 277			set_in_cr4(X86_CR4_SMEP);
 278	}
 279}
 280
 281/*
 282 * Some CPU features depend on higher CPUID levels, which may not always
 283 * be available due to CPUID level capping or broken virtualization
 284 * software.  Add those features to this table to auto-disable them.
 285 */
 286struct cpuid_dependent_feature {
 287	u32 feature;
 288	u32 level;
 289};
 290
 291static const struct cpuid_dependent_feature __cpuinitconst
 292cpuid_dependent_features[] = {
 293	{ X86_FEATURE_MWAIT,		0x00000005 },
 294	{ X86_FEATURE_DCA,		0x00000009 },
 295	{ X86_FEATURE_XSAVE,		0x0000000d },
 296	{ 0, 0 }
 297};
 298
 299static void __cpuinit filter_cpuid_features(struct cpuinfo_x86 *c, bool warn)
 300{
 301	const struct cpuid_dependent_feature *df;
 302
 303	for (df = cpuid_dependent_features; df->feature; df++) {
 304
 305		if (!cpu_has(c, df->feature))
 306			continue;
 307		/*
 308		 * Note: cpuid_level is set to -1 if unavailable, but
 309		 * extended_extended_level is set to 0 if unavailable
 310		 * and the legitimate extended levels are all negative
 311		 * when signed; hence the weird messing around with
 312		 * signs here...
 313		 */
 314		if (!((s32)df->level < 0 ?
 315		     (u32)df->level > (u32)c->extended_cpuid_level :
 316		     (s32)df->level > (s32)c->cpuid_level))
 317			continue;
 318
 319		clear_cpu_cap(c, df->feature);
 320		if (!warn)
 321			continue;
 322
 323		printk(KERN_WARNING
 324		       "CPU: CPU feature %s disabled, no CPUID level 0x%x\n",
 325				x86_cap_flags[df->feature], df->level);
 326	}
 327}
 328
 329/*
 330 * Naming convention should be: <Name> [(<Codename>)]
 331 * This table only is used unless init_<vendor>() below doesn't set it;
 332 * in particular, if CPUID levels 0x80000002..4 are supported, this
 333 * isn't used
 334 */
 335
 336/* Look up CPU names by table lookup. */
 337static const char *__cpuinit table_lookup_model(struct cpuinfo_x86 *c)
 338{
 339	const struct cpu_model_info *info;
 340
 341	if (c->x86_model >= 16)
 342		return NULL;	/* Range check */
 343
 344	if (!this_cpu)
 345		return NULL;
 346
 347	info = this_cpu->c_models;
 348
 349	while (info && info->family) {
 350		if (info->family == c->x86)
 351			return info->model_names[c->x86_model];
 352		info++;
 353	}
 354	return NULL;		/* Not found */
 355}
 356
 357__u32 cpu_caps_cleared[NCAPINTS] __cpuinitdata;
 358__u32 cpu_caps_set[NCAPINTS] __cpuinitdata;
 359
 360void load_percpu_segment(int cpu)
 361{
 362#ifdef CONFIG_X86_32
 363	loadsegment(fs, __KERNEL_PERCPU);
 364#else
 365	loadsegment(gs, 0);
 366	wrmsrl(MSR_GS_BASE, (unsigned long)per_cpu(irq_stack_union.gs_base, cpu));
 367#endif
 368	load_stack_canary_segment();
 369}
 370
 371/*
 372 * Current gdt points %fs at the "master" per-cpu area: after this,
 373 * it's on the real one.
 374 */
 375void switch_to_new_gdt(int cpu)
 376{
 377	struct desc_ptr gdt_descr;
 378
 379	gdt_descr.address = (long)get_cpu_gdt_table(cpu);
 380	gdt_descr.size = GDT_SIZE - 1;
 381	load_gdt(&gdt_descr);
 382	/* Reload the per-cpu base */
 383
 384	load_percpu_segment(cpu);
 385}
 386
 387static const struct cpu_dev *__cpuinitdata cpu_devs[X86_VENDOR_NUM] = {};
 388
 389static void __cpuinit get_model_name(struct cpuinfo_x86 *c)
 390{
 391	unsigned int *v;
 392	char *p, *q;
 393
 394	if (c->extended_cpuid_level < 0x80000004)
 395		return;
 396
 397	v = (unsigned int *)c->x86_model_id;
 398	cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
 399	cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
 400	cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
 401	c->x86_model_id[48] = 0;
 402
 403	/*
 404	 * Intel chips right-justify this string for some dumb reason;
 405	 * undo that brain damage:
 406	 */
 407	p = q = &c->x86_model_id[0];
 408	while (*p == ' ')
 409		p++;
 410	if (p != q) {
 411		while (*p)
 412			*q++ = *p++;
 413		while (q <= &c->x86_model_id[48])
 414			*q++ = '\0';	/* Zero-pad the rest */
 415	}
 416}
 417
 418void __cpuinit cpu_detect_cache_sizes(struct cpuinfo_x86 *c)
 419{
 420	unsigned int n, dummy, ebx, ecx, edx, l2size;
 421
 422	n = c->extended_cpuid_level;
 423
 424	if (n >= 0x80000005) {
 425		cpuid(0x80000005, &dummy, &ebx, &ecx, &edx);
 426		c->x86_cache_size = (ecx>>24) + (edx>>24);
 427#ifdef CONFIG_X86_64
 428		/* On K8 L1 TLB is inclusive, so don't count it */
 429		c->x86_tlbsize = 0;
 430#endif
 431	}
 432
 433	if (n < 0x80000006)	/* Some chips just has a large L1. */
 434		return;
 435
 436	cpuid(0x80000006, &dummy, &ebx, &ecx, &edx);
 437	l2size = ecx >> 16;
 438
 439#ifdef CONFIG_X86_64
 440	c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff);
 441#else
 442	/* do processor-specific cache resizing */
 443	if (this_cpu->c_size_cache)
 444		l2size = this_cpu->c_size_cache(c, l2size);
 445
 446	/* Allow user to override all this if necessary. */
 447	if (cachesize_override != -1)
 448		l2size = cachesize_override;
 449
 450	if (l2size == 0)
 451		return;		/* Again, no L2 cache is possible */
 452#endif
 453
 454	c->x86_cache_size = l2size;
 455}
 456
 457void __cpuinit detect_ht(struct cpuinfo_x86 *c)
 458{
 459#ifdef CONFIG_X86_HT
 460	u32 eax, ebx, ecx, edx;
 461	int index_msb, core_bits;
 462	static bool printed;
 463
 464	if (!cpu_has(c, X86_FEATURE_HT))
 465		return;
 466
 467	if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
 468		goto out;
 469
 470	if (cpu_has(c, X86_FEATURE_XTOPOLOGY))
 471		return;
 472
 473	cpuid(1, &eax, &ebx, &ecx, &edx);
 474
 475	smp_num_siblings = (ebx & 0xff0000) >> 16;
 476
 477	if (smp_num_siblings == 1) {
 478		printk_once(KERN_INFO "CPU0: Hyper-Threading is disabled\n");
 479		goto out;
 480	}
 481
 482	if (smp_num_siblings <= 1)
 483		goto out;
 484
 485	index_msb = get_count_order(smp_num_siblings);
 486	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);
 487
 488	smp_num_siblings = smp_num_siblings / c->x86_max_cores;
 489
 490	index_msb = get_count_order(smp_num_siblings);
 491
 492	core_bits = get_count_order(c->x86_max_cores);
 493
 494	c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, index_msb) &
 495				       ((1 << core_bits) - 1);
 496
 497out:
 498	if (!printed && (c->x86_max_cores * smp_num_siblings) > 1) {
 499		printk(KERN_INFO  "CPU: Physical Processor ID: %d\n",
 500		       c->phys_proc_id);
 501		printk(KERN_INFO  "CPU: Processor Core ID: %d\n",
 502		       c->cpu_core_id);
 503		printed = 1;
 504	}
 505#endif
 506}
 507
 508static void __cpuinit get_cpu_vendor(struct cpuinfo_x86 *c)
 509{
 510	char *v = c->x86_vendor_id;
 511	int i;
 512
 513	for (i = 0; i < X86_VENDOR_NUM; i++) {
 514		if (!cpu_devs[i])
 515			break;
 516
 517		if (!strcmp(v, cpu_devs[i]->c_ident[0]) ||
 518		    (cpu_devs[i]->c_ident[1] &&
 519		     !strcmp(v, cpu_devs[i]->c_ident[1]))) {
 520
 521			this_cpu = cpu_devs[i];
 522			c->x86_vendor = this_cpu->c_x86_vendor;
 523			return;
 524		}
 525	}
 526
 527	printk_once(KERN_ERR
 528			"CPU: vendor_id '%s' unknown, using generic init.\n" \
 529			"CPU: Your system may be unstable.\n", v);
 530
 531	c->x86_vendor = X86_VENDOR_UNKNOWN;
 532	this_cpu = &default_cpu;
 533}
 534
 535void __cpuinit cpu_detect(struct cpuinfo_x86 *c)
 536{
 537	/* Get vendor name */
 538	cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
 539	      (unsigned int *)&c->x86_vendor_id[0],
 540	      (unsigned int *)&c->x86_vendor_id[8],
 541	      (unsigned int *)&c->x86_vendor_id[4]);
 542
 543	c->x86 = 4;
 544	/* Intel-defined flags: level 0x00000001 */
 545	if (c->cpuid_level >= 0x00000001) {
 546		u32 junk, tfms, cap0, misc;
 547
 548		cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
 549		c->x86 = (tfms >> 8) & 0xf;
 550		c->x86_model = (tfms >> 4) & 0xf;
 551		c->x86_mask = tfms & 0xf;
 552
 553		if (c->x86 == 0xf)
 554			c->x86 += (tfms >> 20) & 0xff;
 555		if (c->x86 >= 0x6)
 556			c->x86_model += ((tfms >> 16) & 0xf) << 4;
 557
 558		if (cap0 & (1<<19)) {
 559			c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
 560			c->x86_cache_alignment = c->x86_clflush_size;
 561		}
 562	}
 563}
 564
 565void __cpuinit get_cpu_cap(struct cpuinfo_x86 *c)
 566{
 567	u32 tfms, xlvl;
 568	u32 ebx;
 569
 570	/* Intel-defined flags: level 0x00000001 */
 571	if (c->cpuid_level >= 0x00000001) {
 572		u32 capability, excap;
 573
 574		cpuid(0x00000001, &tfms, &ebx, &excap, &capability);
 575		c->x86_capability[0] = capability;
 576		c->x86_capability[4] = excap;
 577	}
 578
 579	/* Additional Intel-defined flags: level 0x00000007 */
 580	if (c->cpuid_level >= 0x00000007) {
 581		u32 eax, ebx, ecx, edx;
 582
 583		cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx);
 584
 585		c->x86_capability[9] = ebx;
 586	}
 587
 588	/* AMD-defined flags: level 0x80000001 */
 589	xlvl = cpuid_eax(0x80000000);
 590	c->extended_cpuid_level = xlvl;
 591
 592	if ((xlvl & 0xffff0000) == 0x80000000) {
 593		if (xlvl >= 0x80000001) {
 594			c->x86_capability[1] = cpuid_edx(0x80000001);
 595			c->x86_capability[6] = cpuid_ecx(0x80000001);
 596		}
 597	}
 598
 599	if (c->extended_cpuid_level >= 0x80000008) {
 600		u32 eax = cpuid_eax(0x80000008);
 601
 602		c->x86_virt_bits = (eax >> 8) & 0xff;
 603		c->x86_phys_bits = eax & 0xff;
 604	}
 605#ifdef CONFIG_X86_32
 606	else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36))
 607		c->x86_phys_bits = 36;
 608#endif
 609
 610	if (c->extended_cpuid_level >= 0x80000007)
 611		c->x86_power = cpuid_edx(0x80000007);
 612
 613	init_scattered_cpuid_features(c);
 614}
 615
 616static void __cpuinit identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
 617{
 618#ifdef CONFIG_X86_32
 619	int i;
 620
 621	/*
 622	 * First of all, decide if this is a 486 or higher
 623	 * It's a 486 if we can modify the AC flag
 624	 */
 625	if (flag_is_changeable_p(X86_EFLAGS_AC))
 626		c->x86 = 4;
 627	else
 628		c->x86 = 3;
 629
 630	for (i = 0; i < X86_VENDOR_NUM; i++)
 631		if (cpu_devs[i] && cpu_devs[i]->c_identify) {
 632			c->x86_vendor_id[0] = 0;
 633			cpu_devs[i]->c_identify(c);
 634			if (c->x86_vendor_id[0]) {
 635				get_cpu_vendor(c);
 636				break;
 637			}
 638		}
 639#endif
 640}
 641
 642/*
 643 * Do minimum CPU detection early.
 644 * Fields really needed: vendor, cpuid_level, family, model, mask,
 645 * cache alignment.
 646 * The others are not touched to avoid unwanted side effects.
 647 *
 648 * WARNING: this function is only called on the BP.  Don't add code here
 649 * that is supposed to run on all CPUs.
 650 */
 651static void __init early_identify_cpu(struct cpuinfo_x86 *c)
 652{
 653#ifdef CONFIG_X86_64
 654	c->x86_clflush_size = 64;
 655	c->x86_phys_bits = 36;
 656	c->x86_virt_bits = 48;
 657#else
 658	c->x86_clflush_size = 32;
 659	c->x86_phys_bits = 32;
 660	c->x86_virt_bits = 32;
 661#endif
 662	c->x86_cache_alignment = c->x86_clflush_size;
 663
 664	memset(&c->x86_capability, 0, sizeof c->x86_capability);
 665	c->extended_cpuid_level = 0;
 666
 667	if (!have_cpuid_p())
 668		identify_cpu_without_cpuid(c);
 669
 670	/* cyrix could have cpuid enabled via c_identify()*/
 671	if (!have_cpuid_p())
 672		return;
 673
 674	cpu_detect(c);
 675
 676	get_cpu_vendor(c);
 677
 678	get_cpu_cap(c);
 679
 680	if (this_cpu->c_early_init)
 681		this_cpu->c_early_init(c);
 682
 683	c->cpu_index = 0;
 684	filter_cpuid_features(c, false);
 685
 686	setup_smep(c);
 687
 688	if (this_cpu->c_bsp_init)
 689		this_cpu->c_bsp_init(c);
 690}
 691
 692void __init early_cpu_init(void)
 693{
 694	const struct cpu_dev *const *cdev;
 695	int count = 0;
 696
 697#ifdef CONFIG_PROCESSOR_SELECT
 698	printk(KERN_INFO "KERNEL supported cpus:\n");
 699#endif
 700
 701	for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) {
 702		const struct cpu_dev *cpudev = *cdev;
 703
 704		if (count >= X86_VENDOR_NUM)
 705			break;
 706		cpu_devs[count] = cpudev;
 707		count++;
 708
 709#ifdef CONFIG_PROCESSOR_SELECT
 710		{
 711			unsigned int j;
 712
 713			for (j = 0; j < 2; j++) {
 714				if (!cpudev->c_ident[j])
 715					continue;
 716				printk(KERN_INFO "  %s %s\n", cpudev->c_vendor,
 717					cpudev->c_ident[j]);
 718			}
 719		}
 720#endif
 721	}
 722	early_identify_cpu(&boot_cpu_data);
 723}
 724
 725/*
 726 * The NOPL instruction is supposed to exist on all CPUs of family >= 6;
 727 * unfortunately, that's not true in practice because of early VIA
 728 * chips and (more importantly) broken virtualizers that are not easy
 729 * to detect. In the latter case it doesn't even *fail* reliably, so
 730 * probing for it doesn't even work. Disable it completely on 32-bit
 731 * unless we can find a reliable way to detect all the broken cases.
 732 * Enable it explicitly on 64-bit for non-constant inputs of cpu_has().
 733 */
 734static void __cpuinit detect_nopl(struct cpuinfo_x86 *c)
 735{
 736#ifdef CONFIG_X86_32
 737	clear_cpu_cap(c, X86_FEATURE_NOPL);
 738#else
 739	set_cpu_cap(c, X86_FEATURE_NOPL);
 740#endif
 741}
 742
 743static void __cpuinit generic_identify(struct cpuinfo_x86 *c)
 744{
 745	c->extended_cpuid_level = 0;
 746
 747	if (!have_cpuid_p())
 748		identify_cpu_without_cpuid(c);
 749
 750	/* cyrix could have cpuid enabled via c_identify()*/
 751	if (!have_cpuid_p())
 752		return;
 753
 754	cpu_detect(c);
 755
 756	get_cpu_vendor(c);
 757
 758	get_cpu_cap(c);
 759
 760	if (c->cpuid_level >= 0x00000001) {
 761		c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF;
 762#ifdef CONFIG_X86_32
 763# ifdef CONFIG_X86_HT
 764		c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
 765# else
 766		c->apicid = c->initial_apicid;
 767# endif
 768#endif
 769		c->phys_proc_id = c->initial_apicid;
 770	}
 771
 772	setup_smep(c);
 773
 774	get_model_name(c); /* Default name */
 775
 776	detect_nopl(c);
 777}
 778
 779/*
 780 * This does the hard work of actually picking apart the CPU stuff...
 781 */
 782static void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
 783{
 784	int i;
 785
 786	c->loops_per_jiffy = loops_per_jiffy;
 787	c->x86_cache_size = -1;
 788	c->x86_vendor = X86_VENDOR_UNKNOWN;
 789	c->x86_model = c->x86_mask = 0;	/* So far unknown... */
 790	c->x86_vendor_id[0] = '\0'; /* Unset */
 791	c->x86_model_id[0] = '\0';  /* Unset */
 792	c->x86_max_cores = 1;
 793	c->x86_coreid_bits = 0;
 794#ifdef CONFIG_X86_64
 795	c->x86_clflush_size = 64;
 796	c->x86_phys_bits = 36;
 797	c->x86_virt_bits = 48;
 798#else
 799	c->cpuid_level = -1;	/* CPUID not detected */
 800	c->x86_clflush_size = 32;
 801	c->x86_phys_bits = 32;
 802	c->x86_virt_bits = 32;
 803#endif
 804	c->x86_cache_alignment = c->x86_clflush_size;
 805	memset(&c->x86_capability, 0, sizeof c->x86_capability);
 806
 807	generic_identify(c);
 808
 809	if (this_cpu->c_identify)
 810		this_cpu->c_identify(c);
 811
 812	/* Clear/Set all flags overriden by options, after probe */
 813	for (i = 0; i < NCAPINTS; i++) {
 814		c->x86_capability[i] &= ~cpu_caps_cleared[i];
 815		c->x86_capability[i] |= cpu_caps_set[i];
 816	}
 817
 818#ifdef CONFIG_X86_64
 819	c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
 820#endif
 821
 822	/*
 823	 * Vendor-specific initialization.  In this section we
 824	 * canonicalize the feature flags, meaning if there are
 825	 * features a certain CPU supports which CPUID doesn't
 826	 * tell us, CPUID claiming incorrect flags, or other bugs,
 827	 * we handle them here.
 828	 *
 829	 * At the end of this section, c->x86_capability better
 830	 * indicate the features this CPU genuinely supports!
 831	 */
 832	if (this_cpu->c_init)
 833		this_cpu->c_init(c);
 834
 835	/* Disable the PN if appropriate */
 836	squash_the_stupid_serial_number(c);
 837
 838	/*
 839	 * The vendor-specific functions might have changed features.
 840	 * Now we do "generic changes."
 841	 */
 842
 843	/* Filter out anything that depends on CPUID levels we don't have */
 844	filter_cpuid_features(c, true);
 845
 846	/* If the model name is still unset, do table lookup. */
 847	if (!c->x86_model_id[0]) {
 848		const char *p;
 849		p = table_lookup_model(c);
 850		if (p)
 851			strcpy(c->x86_model_id, p);
 852		else
 853			/* Last resort... */
 854			sprintf(c->x86_model_id, "%02x/%02x",
 855				c->x86, c->x86_model);
 856	}
 857
 858#ifdef CONFIG_X86_64
 859	detect_ht(c);
 860#endif
 861
 862	init_hypervisor(c);
 863	x86_init_rdrand(c);
 864
 865	/*
 866	 * Clear/Set all flags overriden by options, need do it
 867	 * before following smp all cpus cap AND.
 868	 */
 869	for (i = 0; i < NCAPINTS; i++) {
 870		c->x86_capability[i] &= ~cpu_caps_cleared[i];
 871		c->x86_capability[i] |= cpu_caps_set[i];
 872	}
 873
 874	/*
 875	 * On SMP, boot_cpu_data holds the common feature set between
 876	 * all CPUs; so make sure that we indicate which features are
 877	 * common between the CPUs.  The first time this routine gets
 878	 * executed, c == &boot_cpu_data.
 879	 */
 880	if (c != &boot_cpu_data) {
 881		/* AND the already accumulated flags with these */
 882		for (i = 0; i < NCAPINTS; i++)
 883			boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
 884	}
 885
 886	/* Init Machine Check Exception if available. */
 887	mcheck_cpu_init(c);
 888
 889	select_idle_routine(c);
 890
 891#ifdef CONFIG_NUMA
 892	numa_add_cpu(smp_processor_id());
 893#endif
 894}
 895
 896#ifdef CONFIG_X86_64
 897static void vgetcpu_set_mode(void)
 898{
 899	if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))
 900		vgetcpu_mode = VGETCPU_RDTSCP;
 901	else
 902		vgetcpu_mode = VGETCPU_LSL;
 903}
 904#endif
 905
 906void __init identify_boot_cpu(void)
 907{
 908	identify_cpu(&boot_cpu_data);
 909	init_amd_e400_c1e_mask();
 910#ifdef CONFIG_X86_32
 911	sysenter_setup();
 912	enable_sep_cpu();
 913#else
 914	vgetcpu_set_mode();
 915#endif
 916}
 917
 918void __cpuinit identify_secondary_cpu(struct cpuinfo_x86 *c)
 919{
 920	BUG_ON(c == &boot_cpu_data);
 921	identify_cpu(c);
 922#ifdef CONFIG_X86_32
 923	enable_sep_cpu();
 924#endif
 925	mtrr_ap_init();
 926}
 927
 928struct msr_range {
 929	unsigned	min;
 930	unsigned	max;
 931};
 932
 933static const struct msr_range msr_range_array[] __cpuinitconst = {
 934	{ 0x00000000, 0x00000418},
 935	{ 0xc0000000, 0xc000040b},
 936	{ 0xc0010000, 0xc0010142},
 937	{ 0xc0011000, 0xc001103b},
 938};
 939
 940static void __cpuinit __print_cpu_msr(void)
 941{
 942	unsigned index_min, index_max;
 943	unsigned index;
 944	u64 val;
 945	int i;
 946
 947	for (i = 0; i < ARRAY_SIZE(msr_range_array); i++) {
 948		index_min = msr_range_array[i].min;
 949		index_max = msr_range_array[i].max;
 950
 951		for (index = index_min; index < index_max; index++) {
 952			if (rdmsrl_amd_safe(index, &val))
 953				continue;
 954			printk(KERN_INFO " MSR%08x: %016llx\n", index, val);
 955		}
 956	}
 957}
 958
 959static int show_msr __cpuinitdata;
 960
 961static __init int setup_show_msr(char *arg)
 962{
 963	int num;
 964
 965	get_option(&arg, &num);
 966
 967	if (num > 0)
 968		show_msr = num;
 969	return 1;
 970}
 971__setup("show_msr=", setup_show_msr);
 972
 973static __init int setup_noclflush(char *arg)
 974{
 975	setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
 976	return 1;
 977}
 978__setup("noclflush", setup_noclflush);
 979
 980void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
 981{
 982	const char *vendor = NULL;
 983
 984	if (c->x86_vendor < X86_VENDOR_NUM) {
 985		vendor = this_cpu->c_vendor;
 986	} else {
 987		if (c->cpuid_level >= 0)
 988			vendor = c->x86_vendor_id;
 989	}
 990
 991	if (vendor && !strstr(c->x86_model_id, vendor))
 992		printk(KERN_CONT "%s ", vendor);
 993
 994	if (c->x86_model_id[0])
 995		printk(KERN_CONT "%s", c->x86_model_id);
 996	else
 997		printk(KERN_CONT "%d86", c->x86);
 998
 999	if (c->x86_mask || c->cpuid_level >= 0)
1000		printk(KERN_CONT " stepping %02x\n", c->x86_mask);
1001	else
1002		printk(KERN_CONT "\n");
1003
1004	print_cpu_msr(c);
1005}
1006
1007void __cpuinit print_cpu_msr(struct cpuinfo_x86 *c)
1008{
1009	if (c->cpu_index < show_msr)
1010		__print_cpu_msr();
1011}
1012
1013static __init int setup_disablecpuid(char *arg)
1014{
1015	int bit;
1016
1017	if (get_option(&arg, &bit) && bit < NCAPINTS*32)
1018		setup_clear_cpu_cap(bit);
1019	else
1020		return 0;
1021
1022	return 1;
1023}
1024__setup("clearcpuid=", setup_disablecpuid);
1025
1026#ifdef CONFIG_X86_64
1027struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
1028struct desc_ptr nmi_idt_descr = { NR_VECTORS * 16 - 1,
1029				    (unsigned long) nmi_idt_table };
1030
1031DEFINE_PER_CPU_FIRST(union irq_stack_union,
1032		     irq_stack_union) __aligned(PAGE_SIZE);
1033
1034/*
1035 * The following four percpu variables are hot.  Align current_task to
1036 * cacheline size such that all four fall in the same cacheline.
1037 */
1038DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
1039	&init_task;
1040EXPORT_PER_CPU_SYMBOL(current_task);
1041
1042DEFINE_PER_CPU(unsigned long, kernel_stack) =
1043	(unsigned long)&init_thread_union - KERNEL_STACK_OFFSET + THREAD_SIZE;
1044EXPORT_PER_CPU_SYMBOL(kernel_stack);
1045
1046DEFINE_PER_CPU(char *, irq_stack_ptr) =
1047	init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64;
1048
1049DEFINE_PER_CPU(unsigned int, irq_count) = -1;
1050
1051DEFINE_PER_CPU(struct task_struct *, fpu_owner_task);
1052
1053/*
1054 * Special IST stacks which the CPU switches to when it calls
1055 * an IST-marked descriptor entry. Up to 7 stacks (hardware
1056 * limit), all of them are 4K, except the debug stack which
1057 * is 8K.
1058 */
1059static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
1060	  [0 ... N_EXCEPTION_STACKS - 1]	= EXCEPTION_STKSZ,
1061	  [DEBUG_STACK - 1]			= DEBUG_STKSZ
1062};
1063
1064static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
1065	[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
1066
1067/* May not be marked __init: used by software suspend */
1068void syscall_init(void)
1069{
1070	/*
1071	 * LSTAR and STAR live in a bit strange symbiosis.
1072	 * They both write to the same internal register. STAR allows to
1073	 * set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
1074	 */
1075	wrmsrl(MSR_STAR,  ((u64)__USER32_CS)<<48  | ((u64)__KERNEL_CS)<<32);
1076	wrmsrl(MSR_LSTAR, system_call);
1077	wrmsrl(MSR_CSTAR, ignore_sysret);
1078
1079#ifdef CONFIG_IA32_EMULATION
1080	syscall32_cpu_init();
1081#endif
1082
1083	/* Flags to clear on syscall */
1084	wrmsrl(MSR_SYSCALL_MASK,
1085	       X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF|X86_EFLAGS_IOPL);
1086}
1087
1088unsigned long kernel_eflags;
1089
1090/*
1091 * Copies of the original ist values from the tss are only accessed during
1092 * debugging, no special alignment required.
1093 */
1094DEFINE_PER_CPU(struct orig_ist, orig_ist);
1095
1096static DEFINE_PER_CPU(unsigned long, debug_stack_addr);
1097DEFINE_PER_CPU(int, debug_stack_usage);
1098
1099int is_debug_stack(unsigned long addr)
1100{
1101	return __get_cpu_var(debug_stack_usage) ||
1102		(addr <= __get_cpu_var(debug_stack_addr) &&
1103		 addr > (__get_cpu_var(debug_stack_addr) - DEBUG_STKSZ));
1104}
1105
1106static DEFINE_PER_CPU(u32, debug_stack_use_ctr);
1107
1108void debug_stack_set_zero(void)
1109{
1110	this_cpu_inc(debug_stack_use_ctr);
1111	load_idt((const struct desc_ptr *)&nmi_idt_descr);
1112}
1113
1114void debug_stack_reset(void)
1115{
1116	if (WARN_ON(!this_cpu_read(debug_stack_use_ctr)))
1117		return;
1118	if (this_cpu_dec_return(debug_stack_use_ctr) == 0)
1119		load_idt((const struct desc_ptr *)&idt_descr);
1120}
1121
1122#else	/* CONFIG_X86_64 */
1123
1124DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
1125EXPORT_PER_CPU_SYMBOL(current_task);
1126DEFINE_PER_CPU(struct task_struct *, fpu_owner_task);
1127
1128#ifdef CONFIG_CC_STACKPROTECTOR
1129DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary);
1130#endif
1131
1132/* Make sure %fs and %gs are initialized properly in idle threads */
1133struct pt_regs * __cpuinit idle_regs(struct pt_regs *regs)
1134{
1135	memset(regs, 0, sizeof(struct pt_regs));
1136	regs->fs = __KERNEL_PERCPU;
1137	regs->gs = __KERNEL_STACK_CANARY;
1138
1139	return regs;
1140}
1141#endif	/* CONFIG_X86_64 */
1142
1143/*
1144 * Clear all 6 debug registers:
1145 */
1146static void clear_all_debug_regs(void)
1147{
1148	int i;
1149
1150	for (i = 0; i < 8; i++) {
1151		/* Ignore db4, db5 */
1152		if ((i == 4) || (i == 5))
1153			continue;
1154
1155		set_debugreg(0, i);
1156	}
1157}
1158
1159#ifdef CONFIG_KGDB
1160/*
1161 * Restore debug regs if using kgdbwait and you have a kernel debugger
1162 * connection established.
1163 */
1164static void dbg_restore_debug_regs(void)
1165{
1166	if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break))
1167		arch_kgdb_ops.correct_hw_break();
1168}
1169#else /* ! CONFIG_KGDB */
1170#define dbg_restore_debug_regs()
1171#endif /* ! CONFIG_KGDB */
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
1182void __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 && this_cpu_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
1279void __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