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Linux/arch/x86/kernel/cpu/common.c

  1 #include <linux/bootmem.h>
  2 #include <linux/linkage.h>
  3 #include <linux/bitops.h>
  4 #include <linux/kernel.h>
  5 #include <linux/export.h>
  6 #include <linux/percpu.h>
  7 #include <linux/string.h>
  8 #include <linux/ctype.h>
  9 #include <linux/delay.h>
 10 #include <linux/sched.h>
 11 #include <linux/init.h>
 12 #include <linux/kprobes.h>
 13 #include <linux/kgdb.h>
 14 #include <linux/smp.h>
 15 #include <linux/io.h>
 16 #include <linux/syscore_ops.h>
 17 
 18 #include <asm/stackprotector.h>
 19 #include <asm/perf_event.h>
 20 #include <asm/mmu_context.h>
 21 #include <asm/archrandom.h>
 22 #include <asm/hypervisor.h>
 23 #include <asm/processor.h>
 24 #include <asm/tlbflush.h>
 25 #include <asm/debugreg.h>
 26 #include <asm/sections.h>
 27 #include <asm/vsyscall.h>
 28 #include <linux/topology.h>
 29 #include <linux/cpumask.h>
 30 #include <asm/pgtable.h>
 31 #include <linux/atomic.h>
 32 #include <asm/proto.h>
 33 #include <asm/setup.h>
 34 #include <asm/apic.h>
 35 #include <asm/desc.h>
 36 #include <asm/fpu/internal.h>
 37 #include <asm/mtrr.h>
 38 #include <linux/numa.h>
 39 #include <asm/asm.h>
 40 #include <asm/bugs.h>
 41 #include <asm/cpu.h>
 42 #include <asm/mce.h>
 43 #include <asm/msr.h>
 44 #include <asm/pat.h>
 45 #include <asm/microcode.h>
 46 #include <asm/microcode_intel.h>
 47 
 48 #ifdef CONFIG_X86_LOCAL_APIC
 49 #include <asm/uv/uv.h>
 50 #endif
 51 
 52 #include "cpu.h"
 53 
 54 /* all of these masks are initialized in setup_cpu_local_masks() */
 55 cpumask_var_t cpu_initialized_mask;
 56 cpumask_var_t cpu_callout_mask;
 57 cpumask_var_t cpu_callin_mask;
 58 
 59 /* representing cpus for which sibling maps can be computed */
 60 cpumask_var_t cpu_sibling_setup_mask;
 61 
 62 /* correctly size the local cpu masks */
 63 void __init setup_cpu_local_masks(void)
 64 {
 65         alloc_bootmem_cpumask_var(&cpu_initialized_mask);
 66         alloc_bootmem_cpumask_var(&cpu_callin_mask);
 67         alloc_bootmem_cpumask_var(&cpu_callout_mask);
 68         alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask);
 69 }
 70 
 71 static void default_init(struct cpuinfo_x86 *c)
 72 {
 73 #ifdef CONFIG_X86_64
 74         cpu_detect_cache_sizes(c);
 75 #else
 76         /* Not much we can do here... */
 77         /* Check if at least it has cpuid */
 78         if (c->cpuid_level == -1) {
 79                 /* No cpuid. It must be an ancient CPU */
 80                 if (c->x86 == 4)
 81                         strcpy(c->x86_model_id, "486");
 82                 else if (c->x86 == 3)
 83                         strcpy(c->x86_model_id, "386");
 84         }
 85 #endif
 86 }
 87 
 88 static const struct cpu_dev default_cpu = {
 89         .c_init         = default_init,
 90         .c_vendor       = "Unknown",
 91         .c_x86_vendor   = X86_VENDOR_UNKNOWN,
 92 };
 93 
 94 static const struct cpu_dev *this_cpu = &default_cpu;
 95 
 96 DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = {
 97 #ifdef CONFIG_X86_64
 98         /*
 99          * We need valid kernel segments for data and code in long mode too
100          * IRET will check the segment types  kkeil 2000/10/28
101          * Also sysret mandates a special GDT layout
102          *
103          * TLS descriptors are currently at a different place compared to i386.
104          * Hopefully nobody expects them at a fixed place (Wine?)
105          */
106         [GDT_ENTRY_KERNEL32_CS]         = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff),
107         [GDT_ENTRY_KERNEL_CS]           = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff),
108         [GDT_ENTRY_KERNEL_DS]           = GDT_ENTRY_INIT(0xc093, 0, 0xfffff),
109         [GDT_ENTRY_DEFAULT_USER32_CS]   = GDT_ENTRY_INIT(0xc0fb, 0, 0xfffff),
110         [GDT_ENTRY_DEFAULT_USER_DS]     = GDT_ENTRY_INIT(0xc0f3, 0, 0xfffff),
111         [GDT_ENTRY_DEFAULT_USER_CS]     = GDT_ENTRY_INIT(0xa0fb, 0, 0xfffff),
112 #else
113         [GDT_ENTRY_KERNEL_CS]           = GDT_ENTRY_INIT(0xc09a, 0, 0xfffff),
114         [GDT_ENTRY_KERNEL_DS]           = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
115         [GDT_ENTRY_DEFAULT_USER_CS]     = GDT_ENTRY_INIT(0xc0fa, 0, 0xfffff),
116         [GDT_ENTRY_DEFAULT_USER_DS]     = GDT_ENTRY_INIT(0xc0f2, 0, 0xfffff),
117         /*
118          * Segments used for calling PnP BIOS have byte granularity.
119          * They code segments and data segments have fixed 64k limits,
120          * the transfer segment sizes are set at run time.
121          */
122         /* 32-bit code */
123         [GDT_ENTRY_PNPBIOS_CS32]        = GDT_ENTRY_INIT(0x409a, 0, 0xffff),
124         /* 16-bit code */
125         [GDT_ENTRY_PNPBIOS_CS16]        = GDT_ENTRY_INIT(0x009a, 0, 0xffff),
126         /* 16-bit data */
127         [GDT_ENTRY_PNPBIOS_DS]          = GDT_ENTRY_INIT(0x0092, 0, 0xffff),
128         /* 16-bit data */
129         [GDT_ENTRY_PNPBIOS_TS1]         = GDT_ENTRY_INIT(0x0092, 0, 0),
130         /* 16-bit data */
131         [GDT_ENTRY_PNPBIOS_TS2]         = GDT_ENTRY_INIT(0x0092, 0, 0),
132         /*
133          * The APM segments have byte granularity and their bases
134          * are set at run time.  All have 64k limits.
135          */
136         /* 32-bit code */
137         [GDT_ENTRY_APMBIOS_BASE]        = GDT_ENTRY_INIT(0x409a, 0, 0xffff),
138         /* 16-bit code */
139         [GDT_ENTRY_APMBIOS_BASE+1]      = GDT_ENTRY_INIT(0x009a, 0, 0xffff),
140         /* data */
141         [GDT_ENTRY_APMBIOS_BASE+2]      = GDT_ENTRY_INIT(0x4092, 0, 0xffff),
142 
143         [GDT_ENTRY_ESPFIX_SS]           = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
144         [GDT_ENTRY_PERCPU]              = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
145         GDT_STACK_CANARY_INIT
146 #endif
147 } };
148 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
149 
150 static int __init x86_mpx_setup(char *s)
151 {
152         /* require an exact match without trailing characters */
153         if (strlen(s))
154                 return 0;
155 
156         /* do not emit a message if the feature is not present */
157         if (!boot_cpu_has(X86_FEATURE_MPX))
158                 return 1;
159 
160         setup_clear_cpu_cap(X86_FEATURE_MPX);
161         pr_info("nompx: Intel Memory Protection Extensions (MPX) disabled\n");
162         return 1;
163 }
164 __setup("nompx", x86_mpx_setup);
165 
166 static int __init x86_noinvpcid_setup(char *s)
167 {
168         /* noinvpcid doesn't accept parameters */
169         if (s)
170                 return -EINVAL;
171 
172         /* do not emit a message if the feature is not present */
173         if (!boot_cpu_has(X86_FEATURE_INVPCID))
174                 return 0;
175 
176         setup_clear_cpu_cap(X86_FEATURE_INVPCID);
177         pr_info("noinvpcid: INVPCID feature disabled\n");
178         return 0;
179 }
180 early_param("noinvpcid", x86_noinvpcid_setup);
181 
182 #ifdef CONFIG_X86_32
183 static int cachesize_override = -1;
184 static int disable_x86_serial_nr = 1;
185 
186 static int __init cachesize_setup(char *str)
187 {
188         get_option(&str, &cachesize_override);
189         return 1;
190 }
191 __setup("cachesize=", cachesize_setup);
192 
193 static int __init x86_sep_setup(char *s)
194 {
195         setup_clear_cpu_cap(X86_FEATURE_SEP);
196         return 1;
197 }
198 __setup("nosep", x86_sep_setup);
199 
200 /* Standard macro to see if a specific flag is changeable */
201 static inline int flag_is_changeable_p(u32 flag)
202 {
203         u32 f1, f2;
204 
205         /*
206          * Cyrix and IDT cpus allow disabling of CPUID
207          * so the code below may return different results
208          * when it is executed before and after enabling
209          * the CPUID. Add "volatile" to not allow gcc to
210          * optimize the subsequent calls to this function.
211          */
212         asm volatile ("pushfl           \n\t"
213                       "pushfl           \n\t"
214                       "popl %0          \n\t"
215                       "movl %0, %1      \n\t"
216                       "xorl %2, %0      \n\t"
217                       "pushl %0         \n\t"
218                       "popfl            \n\t"
219                       "pushfl           \n\t"
220                       "popl %0          \n\t"
221                       "popfl            \n\t"
222 
223                       : "=&r" (f1), "=&r" (f2)
224                       : "ir" (flag));
225 
226         return ((f1^f2) & flag) != 0;
227 }
228 
229 /* Probe for the CPUID instruction */
230 int have_cpuid_p(void)
231 {
232         return flag_is_changeable_p(X86_EFLAGS_ID);
233 }
234 
235 static void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
236 {
237         unsigned long lo, hi;
238 
239         if (!cpu_has(c, X86_FEATURE_PN) || !disable_x86_serial_nr)
240                 return;
241 
242         /* Disable processor serial number: */
243 
244         rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
245         lo |= 0x200000;
246         wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
247 
248         pr_notice("CPU serial number disabled.\n");
249         clear_cpu_cap(c, X86_FEATURE_PN);
250 
251         /* Disabling the serial number may affect the cpuid level */
252         c->cpuid_level = cpuid_eax(0);
253 }
254 
255 static int __init x86_serial_nr_setup(char *s)
256 {
257         disable_x86_serial_nr = 0;
258         return 1;
259 }
260 __setup("serialnumber", x86_serial_nr_setup);
261 #else
262 static inline int flag_is_changeable_p(u32 flag)
263 {
264         return 1;
265 }
266 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
267 {
268 }
269 #endif
270 
271 static __init int setup_disable_smep(char *arg)
272 {
273         setup_clear_cpu_cap(X86_FEATURE_SMEP);
274         /* Check for things that depend on SMEP being enabled: */
275         check_mpx_erratum(&boot_cpu_data);
276         return 1;
277 }
278 __setup("nosmep", setup_disable_smep);
279 
280 static __always_inline void setup_smep(struct cpuinfo_x86 *c)
281 {
282         if (cpu_has(c, X86_FEATURE_SMEP))
283                 cr4_set_bits(X86_CR4_SMEP);
284 }
285 
286 static __init int setup_disable_smap(char *arg)
287 {
288         setup_clear_cpu_cap(X86_FEATURE_SMAP);
289         return 1;
290 }
291 __setup("nosmap", setup_disable_smap);
292 
293 static __always_inline void setup_smap(struct cpuinfo_x86 *c)
294 {
295         unsigned long eflags = native_save_fl();
296 
297         /* This should have been cleared long ago */
298         BUG_ON(eflags & X86_EFLAGS_AC);
299 
300         if (cpu_has(c, X86_FEATURE_SMAP)) {
301 #ifdef CONFIG_X86_SMAP
302                 cr4_set_bits(X86_CR4_SMAP);
303 #else
304                 cr4_clear_bits(X86_CR4_SMAP);
305 #endif
306         }
307 }
308 
309 /*
310  * Protection Keys are not available in 32-bit mode.
311  */
312 static bool pku_disabled;
313 
314 static __always_inline void setup_pku(struct cpuinfo_x86 *c)
315 {
316         /* check the boot processor, plus compile options for PKU: */
317         if (!cpu_feature_enabled(X86_FEATURE_PKU))
318                 return;
319         /* checks the actual processor's cpuid bits: */
320         if (!cpu_has(c, X86_FEATURE_PKU))
321                 return;
322         if (pku_disabled)
323                 return;
324 
325         cr4_set_bits(X86_CR4_PKE);
326         /*
327          * Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE
328          * cpuid bit to be set.  We need to ensure that we
329          * update that bit in this CPU's "cpu_info".
330          */
331         get_cpu_cap(c);
332 }
333 
334 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
335 static __init int setup_disable_pku(char *arg)
336 {
337         /*
338          * Do not clear the X86_FEATURE_PKU bit.  All of the
339          * runtime checks are against OSPKE so clearing the
340          * bit does nothing.
341          *
342          * This way, we will see "pku" in cpuinfo, but not
343          * "ospke", which is exactly what we want.  It shows
344          * that the CPU has PKU, but the OS has not enabled it.
345          * This happens to be exactly how a system would look
346          * if we disabled the config option.
347          */
348         pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n");
349         pku_disabled = true;
350         return 1;
351 }
352 __setup("nopku", setup_disable_pku);
353 #endif /* CONFIG_X86_64 */
354 
355 /*
356  * Some CPU features depend on higher CPUID levels, which may not always
357  * be available due to CPUID level capping or broken virtualization
358  * software.  Add those features to this table to auto-disable them.
359  */
360 struct cpuid_dependent_feature {
361         u32 feature;
362         u32 level;
363 };
364 
365 static const struct cpuid_dependent_feature
366 cpuid_dependent_features[] = {
367         { X86_FEATURE_MWAIT,            0x00000005 },
368         { X86_FEATURE_DCA,              0x00000009 },
369         { X86_FEATURE_XSAVE,            0x0000000d },
370         { 0, 0 }
371 };
372 
373 static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn)
374 {
375         const struct cpuid_dependent_feature *df;
376 
377         for (df = cpuid_dependent_features; df->feature; df++) {
378 
379                 if (!cpu_has(c, df->feature))
380                         continue;
381                 /*
382                  * Note: cpuid_level is set to -1 if unavailable, but
383                  * extended_extended_level is set to 0 if unavailable
384                  * and the legitimate extended levels are all negative
385                  * when signed; hence the weird messing around with
386                  * signs here...
387                  */
388                 if (!((s32)df->level < 0 ?
389                      (u32)df->level > (u32)c->extended_cpuid_level :
390                      (s32)df->level > (s32)c->cpuid_level))
391                         continue;
392 
393                 clear_cpu_cap(c, df->feature);
394                 if (!warn)
395                         continue;
396 
397                 pr_warn("CPU: CPU feature " X86_CAP_FMT " disabled, no CPUID level 0x%x\n",
398                         x86_cap_flag(df->feature), df->level);
399         }
400 }
401 
402 /*
403  * Naming convention should be: <Name> [(<Codename>)]
404  * This table only is used unless init_<vendor>() below doesn't set it;
405  * in particular, if CPUID levels 0x80000002..4 are supported, this
406  * isn't used
407  */
408 
409 /* Look up CPU names by table lookup. */
410 static const char *table_lookup_model(struct cpuinfo_x86 *c)
411 {
412 #ifdef CONFIG_X86_32
413         const struct legacy_cpu_model_info *info;
414 
415         if (c->x86_model >= 16)
416                 return NULL;    /* Range check */
417 
418         if (!this_cpu)
419                 return NULL;
420 
421         info = this_cpu->legacy_models;
422 
423         while (info->family) {
424                 if (info->family == c->x86)
425                         return info->model_names[c->x86_model];
426                 info++;
427         }
428 #endif
429         return NULL;            /* Not found */
430 }
431 
432 __u32 cpu_caps_cleared[NCAPINTS];
433 __u32 cpu_caps_set[NCAPINTS];
434 
435 void load_percpu_segment(int cpu)
436 {
437 #ifdef CONFIG_X86_32
438         loadsegment(fs, __KERNEL_PERCPU);
439 #else
440         __loadsegment_simple(gs, 0);
441         wrmsrl(MSR_GS_BASE, (unsigned long)per_cpu(irq_stack_union.gs_base, cpu));
442 #endif
443         load_stack_canary_segment();
444 }
445 
446 /*
447  * Current gdt points %fs at the "master" per-cpu area: after this,
448  * it's on the real one.
449  */
450 void switch_to_new_gdt(int cpu)
451 {
452         struct desc_ptr gdt_descr;
453 
454         gdt_descr.address = (long)get_cpu_gdt_table(cpu);
455         gdt_descr.size = GDT_SIZE - 1;
456         load_gdt(&gdt_descr);
457         /* Reload the per-cpu base */
458 
459         load_percpu_segment(cpu);
460 }
461 
462 static const struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {};
463 
464 static void get_model_name(struct cpuinfo_x86 *c)
465 {
466         unsigned int *v;
467         char *p, *q, *s;
468 
469         if (c->extended_cpuid_level < 0x80000004)
470                 return;
471 
472         v = (unsigned int *)c->x86_model_id;
473         cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
474         cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
475         cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
476         c->x86_model_id[48] = 0;
477 
478         /* Trim whitespace */
479         p = q = s = &c->x86_model_id[0];
480 
481         while (*p == ' ')
482                 p++;
483 
484         while (*p) {
485                 /* Note the last non-whitespace index */
486                 if (!isspace(*p))
487                         s = q;
488 
489                 *q++ = *p++;
490         }
491 
492         *(s + 1) = '\0';
493 }
494 
495 void cpu_detect_cache_sizes(struct cpuinfo_x86 *c)
496 {
497         unsigned int n, dummy, ebx, ecx, edx, l2size;
498 
499         n = c->extended_cpuid_level;
500 
501         if (n >= 0x80000005) {
502                 cpuid(0x80000005, &dummy, &ebx, &ecx, &edx);
503                 c->x86_cache_size = (ecx>>24) + (edx>>24);
504 #ifdef CONFIG_X86_64
505                 /* On K8 L1 TLB is inclusive, so don't count it */
506                 c->x86_tlbsize = 0;
507 #endif
508         }
509 
510         if (n < 0x80000006)     /* Some chips just has a large L1. */
511                 return;
512 
513         cpuid(0x80000006, &dummy, &ebx, &ecx, &edx);
514         l2size = ecx >> 16;
515 
516 #ifdef CONFIG_X86_64
517         c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff);
518 #else
519         /* do processor-specific cache resizing */
520         if (this_cpu->legacy_cache_size)
521                 l2size = this_cpu->legacy_cache_size(c, l2size);
522 
523         /* Allow user to override all this if necessary. */
524         if (cachesize_override != -1)
525                 l2size = cachesize_override;
526 
527         if (l2size == 0)
528                 return;         /* Again, no L2 cache is possible */
529 #endif
530 
531         c->x86_cache_size = l2size;
532 }
533 
534 u16 __read_mostly tlb_lli_4k[NR_INFO];
535 u16 __read_mostly tlb_lli_2m[NR_INFO];
536 u16 __read_mostly tlb_lli_4m[NR_INFO];
537 u16 __read_mostly tlb_lld_4k[NR_INFO];
538 u16 __read_mostly tlb_lld_2m[NR_INFO];
539 u16 __read_mostly tlb_lld_4m[NR_INFO];
540 u16 __read_mostly tlb_lld_1g[NR_INFO];
541 
542 static void cpu_detect_tlb(struct cpuinfo_x86 *c)
543 {
544         if (this_cpu->c_detect_tlb)
545                 this_cpu->c_detect_tlb(c);
546 
547         pr_info("Last level iTLB entries: 4KB %d, 2MB %d, 4MB %d\n",
548                 tlb_lli_4k[ENTRIES], tlb_lli_2m[ENTRIES],
549                 tlb_lli_4m[ENTRIES]);
550 
551         pr_info("Last level dTLB entries: 4KB %d, 2MB %d, 4MB %d, 1GB %d\n",
552                 tlb_lld_4k[ENTRIES], tlb_lld_2m[ENTRIES],
553                 tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]);
554 }
555 
556 void detect_ht(struct cpuinfo_x86 *c)
557 {
558 #ifdef CONFIG_SMP
559         u32 eax, ebx, ecx, edx;
560         int index_msb, core_bits;
561         static bool printed;
562 
563         if (!cpu_has(c, X86_FEATURE_HT))
564                 return;
565 
566         if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
567                 goto out;
568 
569         if (cpu_has(c, X86_FEATURE_XTOPOLOGY))
570                 return;
571 
572         cpuid(1, &eax, &ebx, &ecx, &edx);
573 
574         smp_num_siblings = (ebx & 0xff0000) >> 16;
575 
576         if (smp_num_siblings == 1) {
577                 pr_info_once("CPU0: Hyper-Threading is disabled\n");
578                 goto out;
579         }
580 
581         if (smp_num_siblings <= 1)
582                 goto out;
583 
584         index_msb = get_count_order(smp_num_siblings);
585         c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);
586 
587         smp_num_siblings = smp_num_siblings / c->x86_max_cores;
588 
589         index_msb = get_count_order(smp_num_siblings);
590 
591         core_bits = get_count_order(c->x86_max_cores);
592 
593         c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, index_msb) &
594                                        ((1 << core_bits) - 1);
595 
596 out:
597         if (!printed && (c->x86_max_cores * smp_num_siblings) > 1) {
598                 pr_info("CPU: Physical Processor ID: %d\n",
599                         c->phys_proc_id);
600                 pr_info("CPU: Processor Core ID: %d\n",
601                         c->cpu_core_id);
602                 printed = 1;
603         }
604 #endif
605 }
606 
607 static void get_cpu_vendor(struct cpuinfo_x86 *c)
608 {
609         char *v = c->x86_vendor_id;
610         int i;
611 
612         for (i = 0; i < X86_VENDOR_NUM; i++) {
613                 if (!cpu_devs[i])
614                         break;
615 
616                 if (!strcmp(v, cpu_devs[i]->c_ident[0]) ||
617                     (cpu_devs[i]->c_ident[1] &&
618                      !strcmp(v, cpu_devs[i]->c_ident[1]))) {
619 
620                         this_cpu = cpu_devs[i];
621                         c->x86_vendor = this_cpu->c_x86_vendor;
622                         return;
623                 }
624         }
625 
626         pr_err_once("CPU: vendor_id '%s' unknown, using generic init.\n" \
627                     "CPU: Your system may be unstable.\n", v);
628 
629         c->x86_vendor = X86_VENDOR_UNKNOWN;
630         this_cpu = &default_cpu;
631 }
632 
633 void cpu_detect(struct cpuinfo_x86 *c)
634 {
635         /* Get vendor name */
636         cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
637               (unsigned int *)&c->x86_vendor_id[0],
638               (unsigned int *)&c->x86_vendor_id[8],
639               (unsigned int *)&c->x86_vendor_id[4]);
640 
641         c->x86 = 4;
642         /* Intel-defined flags: level 0x00000001 */
643         if (c->cpuid_level >= 0x00000001) {
644                 u32 junk, tfms, cap0, misc;
645 
646                 cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
647                 c->x86          = x86_family(tfms);
648                 c->x86_model    = x86_model(tfms);
649                 c->x86_mask     = x86_stepping(tfms);
650 
651                 if (cap0 & (1<<19)) {
652                         c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
653                         c->x86_cache_alignment = c->x86_clflush_size;
654                 }
655         }
656 }
657 
658 void get_cpu_cap(struct cpuinfo_x86 *c)
659 {
660         u32 eax, ebx, ecx, edx;
661 
662         /* Intel-defined flags: level 0x00000001 */
663         if (c->cpuid_level >= 0x00000001) {
664                 cpuid(0x00000001, &eax, &ebx, &ecx, &edx);
665 
666                 c->x86_capability[CPUID_1_ECX] = ecx;
667                 c->x86_capability[CPUID_1_EDX] = edx;
668         }
669 
670         /* Additional Intel-defined flags: level 0x00000007 */
671         if (c->cpuid_level >= 0x00000007) {
672                 cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx);
673 
674                 c->x86_capability[CPUID_7_0_EBX] = ebx;
675 
676                 c->x86_capability[CPUID_6_EAX] = cpuid_eax(0x00000006);
677                 c->x86_capability[CPUID_7_ECX] = ecx;
678         }
679 
680         /* Extended state features: level 0x0000000d */
681         if (c->cpuid_level >= 0x0000000d) {
682                 cpuid_count(0x0000000d, 1, &eax, &ebx, &ecx, &edx);
683 
684                 c->x86_capability[CPUID_D_1_EAX] = eax;
685         }
686 
687         /* Additional Intel-defined flags: level 0x0000000F */
688         if (c->cpuid_level >= 0x0000000F) {
689 
690                 /* QoS sub-leaf, EAX=0Fh, ECX=0 */
691                 cpuid_count(0x0000000F, 0, &eax, &ebx, &ecx, &edx);
692                 c->x86_capability[CPUID_F_0_EDX] = edx;
693 
694                 if (cpu_has(c, X86_FEATURE_CQM_LLC)) {
695                         /* will be overridden if occupancy monitoring exists */
696                         c->x86_cache_max_rmid = ebx;
697 
698                         /* QoS sub-leaf, EAX=0Fh, ECX=1 */
699                         cpuid_count(0x0000000F, 1, &eax, &ebx, &ecx, &edx);
700                         c->x86_capability[CPUID_F_1_EDX] = edx;
701 
702                         if ((cpu_has(c, X86_FEATURE_CQM_OCCUP_LLC)) ||
703                               ((cpu_has(c, X86_FEATURE_CQM_MBM_TOTAL)) ||
704                                (cpu_has(c, X86_FEATURE_CQM_MBM_LOCAL)))) {
705                                 c->x86_cache_max_rmid = ecx;
706                                 c->x86_cache_occ_scale = ebx;
707                         }
708                 } else {
709                         c->x86_cache_max_rmid = -1;
710                         c->x86_cache_occ_scale = -1;
711                 }
712         }
713 
714         /* AMD-defined flags: level 0x80000001 */
715         eax = cpuid_eax(0x80000000);
716         c->extended_cpuid_level = eax;
717 
718         if ((eax & 0xffff0000) == 0x80000000) {
719                 if (eax >= 0x80000001) {
720                         cpuid(0x80000001, &eax, &ebx, &ecx, &edx);
721 
722                         c->x86_capability[CPUID_8000_0001_ECX] = ecx;
723                         c->x86_capability[CPUID_8000_0001_EDX] = edx;
724                 }
725         }
726 
727         if (c->extended_cpuid_level >= 0x80000007) {
728                 cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
729 
730                 c->x86_capability[CPUID_8000_0007_EBX] = ebx;
731                 c->x86_power = edx;
732         }
733 
734         if (c->extended_cpuid_level >= 0x80000008) {
735                 cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
736 
737                 c->x86_virt_bits = (eax >> 8) & 0xff;
738                 c->x86_phys_bits = eax & 0xff;
739                 c->x86_capability[CPUID_8000_0008_EBX] = ebx;
740         }
741 #ifdef CONFIG_X86_32
742         else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36))
743                 c->x86_phys_bits = 36;
744 #endif
745 
746         if (c->extended_cpuid_level >= 0x8000000a)
747                 c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a);
748 
749         init_scattered_cpuid_features(c);
750 }
751 
752 static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
753 {
754 #ifdef CONFIG_X86_32
755         int i;
756 
757         /*
758          * First of all, decide if this is a 486 or higher
759          * It's a 486 if we can modify the AC flag
760          */
761         if (flag_is_changeable_p(X86_EFLAGS_AC))
762                 c->x86 = 4;
763         else
764                 c->x86 = 3;
765 
766         for (i = 0; i < X86_VENDOR_NUM; i++)
767                 if (cpu_devs[i] && cpu_devs[i]->c_identify) {
768                         c->x86_vendor_id[0] = 0;
769                         cpu_devs[i]->c_identify(c);
770                         if (c->x86_vendor_id[0]) {
771                                 get_cpu_vendor(c);
772                                 break;
773                         }
774                 }
775 #endif
776 }
777 
778 /*
779  * Do minimum CPU detection early.
780  * Fields really needed: vendor, cpuid_level, family, model, mask,
781  * cache alignment.
782  * The others are not touched to avoid unwanted side effects.
783  *
784  * WARNING: this function is only called on the BP.  Don't add code here
785  * that is supposed to run on all CPUs.
786  */
787 static void __init early_identify_cpu(struct cpuinfo_x86 *c)
788 {
789 #ifdef CONFIG_X86_64
790         c->x86_clflush_size = 64;
791         c->x86_phys_bits = 36;
792         c->x86_virt_bits = 48;
793 #else
794         c->x86_clflush_size = 32;
795         c->x86_phys_bits = 32;
796         c->x86_virt_bits = 32;
797 #endif
798         c->x86_cache_alignment = c->x86_clflush_size;
799 
800         memset(&c->x86_capability, 0, sizeof c->x86_capability);
801         c->extended_cpuid_level = 0;
802 
803         if (!have_cpuid_p())
804                 identify_cpu_without_cpuid(c);
805 
806         /* cyrix could have cpuid enabled via c_identify()*/
807         if (have_cpuid_p()) {
808                 cpu_detect(c);
809                 get_cpu_vendor(c);
810                 get_cpu_cap(c);
811 
812                 if (this_cpu->c_early_init)
813                         this_cpu->c_early_init(c);
814 
815                 c->cpu_index = 0;
816                 filter_cpuid_features(c, false);
817 
818                 if (this_cpu->c_bsp_init)
819                         this_cpu->c_bsp_init(c);
820         }
821 
822         setup_force_cpu_cap(X86_FEATURE_ALWAYS);
823         fpu__init_system(c);
824 }
825 
826 void __init early_cpu_init(void)
827 {
828         const struct cpu_dev *const *cdev;
829         int count = 0;
830 
831 #ifdef CONFIG_PROCESSOR_SELECT
832         pr_info("KERNEL supported cpus:\n");
833 #endif
834 
835         for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) {
836                 const struct cpu_dev *cpudev = *cdev;
837 
838                 if (count >= X86_VENDOR_NUM)
839                         break;
840                 cpu_devs[count] = cpudev;
841                 count++;
842 
843 #ifdef CONFIG_PROCESSOR_SELECT
844                 {
845                         unsigned int j;
846 
847                         for (j = 0; j < 2; j++) {
848                                 if (!cpudev->c_ident[j])
849                                         continue;
850                                 pr_info("  %s %s\n", cpudev->c_vendor,
851                                         cpudev->c_ident[j]);
852                         }
853                 }
854 #endif
855         }
856         early_identify_cpu(&boot_cpu_data);
857 }
858 
859 /*
860  * The NOPL instruction is supposed to exist on all CPUs of family >= 6;
861  * unfortunately, that's not true in practice because of early VIA
862  * chips and (more importantly) broken virtualizers that are not easy
863  * to detect. In the latter case it doesn't even *fail* reliably, so
864  * probing for it doesn't even work. Disable it completely on 32-bit
865  * unless we can find a reliable way to detect all the broken cases.
866  * Enable it explicitly on 64-bit for non-constant inputs of cpu_has().
867  */
868 static void detect_nopl(struct cpuinfo_x86 *c)
869 {
870 #ifdef CONFIG_X86_32
871         clear_cpu_cap(c, X86_FEATURE_NOPL);
872 #else
873         set_cpu_cap(c, X86_FEATURE_NOPL);
874 #endif
875 }
876 
877 static void detect_null_seg_behavior(struct cpuinfo_x86 *c)
878 {
879 #ifdef CONFIG_X86_64
880         /*
881          * Empirically, writing zero to a segment selector on AMD does
882          * not clear the base, whereas writing zero to a segment
883          * selector on Intel does clear the base.  Intel's behavior
884          * allows slightly faster context switches in the common case
885          * where GS is unused by the prev and next threads.
886          *
887          * Since neither vendor documents this anywhere that I can see,
888          * detect it directly instead of hardcoding the choice by
889          * vendor.
890          *
891          * I've designated AMD's behavior as the "bug" because it's
892          * counterintuitive and less friendly.
893          */
894 
895         unsigned long old_base, tmp;
896         rdmsrl(MSR_FS_BASE, old_base);
897         wrmsrl(MSR_FS_BASE, 1);
898         loadsegment(fs, 0);
899         rdmsrl(MSR_FS_BASE, tmp);
900         if (tmp != 0)
901                 set_cpu_bug(c, X86_BUG_NULL_SEG);
902         wrmsrl(MSR_FS_BASE, old_base);
903 #endif
904 }
905 
906 static void generic_identify(struct cpuinfo_x86 *c)
907 {
908         c->extended_cpuid_level = 0;
909 
910         if (!have_cpuid_p())
911                 identify_cpu_without_cpuid(c);
912 
913         /* cyrix could have cpuid enabled via c_identify()*/
914         if (!have_cpuid_p())
915                 return;
916 
917         cpu_detect(c);
918 
919         get_cpu_vendor(c);
920 
921         get_cpu_cap(c);
922 
923         if (c->cpuid_level >= 0x00000001) {
924                 c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF;
925 #ifdef CONFIG_X86_32
926 # ifdef CONFIG_SMP
927                 c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
928 # else
929                 c->apicid = c->initial_apicid;
930 # endif
931 #endif
932                 c->phys_proc_id = c->initial_apicid;
933         }
934 
935         get_model_name(c); /* Default name */
936 
937         detect_nopl(c);
938 
939         detect_null_seg_behavior(c);
940 
941         /*
942          * ESPFIX is a strange bug.  All real CPUs have it.  Paravirt
943          * systems that run Linux at CPL > 0 may or may not have the
944          * issue, but, even if they have the issue, there's absolutely
945          * nothing we can do about it because we can't use the real IRET
946          * instruction.
947          *
948          * NB: For the time being, only 32-bit kernels support
949          * X86_BUG_ESPFIX as such.  64-bit kernels directly choose
950          * whether to apply espfix using paravirt hooks.  If any
951          * non-paravirt system ever shows up that does *not* have the
952          * ESPFIX issue, we can change this.
953          */
954 #ifdef CONFIG_X86_32
955 # ifdef CONFIG_PARAVIRT
956         do {
957                 extern void native_iret(void);
958                 if (pv_cpu_ops.iret == native_iret)
959                         set_cpu_bug(c, X86_BUG_ESPFIX);
960         } while (0);
961 # else
962         set_cpu_bug(c, X86_BUG_ESPFIX);
963 # endif
964 #endif
965 }
966 
967 static void x86_init_cache_qos(struct cpuinfo_x86 *c)
968 {
969         /*
970          * The heavy lifting of max_rmid and cache_occ_scale are handled
971          * in get_cpu_cap().  Here we just set the max_rmid for the boot_cpu
972          * in case CQM bits really aren't there in this CPU.
973          */
974         if (c != &boot_cpu_data) {
975                 boot_cpu_data.x86_cache_max_rmid =
976                         min(boot_cpu_data.x86_cache_max_rmid,
977                             c->x86_cache_max_rmid);
978         }
979 }
980 
981 /*
982  * This does the hard work of actually picking apart the CPU stuff...
983  */
984 static void identify_cpu(struct cpuinfo_x86 *c)
985 {
986         int i;
987 
988         c->loops_per_jiffy = loops_per_jiffy;
989         c->x86_cache_size = -1;
990         c->x86_vendor = X86_VENDOR_UNKNOWN;
991         c->x86_model = c->x86_mask = 0; /* So far unknown... */
992         c->x86_vendor_id[0] = '\0'; /* Unset */
993         c->x86_model_id[0] = '\0';  /* Unset */
994         c->x86_max_cores = 1;
995         c->x86_coreid_bits = 0;
996 #ifdef CONFIG_X86_64
997         c->x86_clflush_size = 64;
998         c->x86_phys_bits = 36;
999         c->x86_virt_bits = 48;
1000 #else
1001         c->cpuid_level = -1;    /* CPUID not detected */
1002         c->x86_clflush_size = 32;
1003         c->x86_phys_bits = 32;
1004         c->x86_virt_bits = 32;
1005 #endif
1006         c->x86_cache_alignment = c->x86_clflush_size;
1007         memset(&c->x86_capability, 0, sizeof c->x86_capability);
1008 
1009         generic_identify(c);
1010 
1011         if (this_cpu->c_identify)
1012                 this_cpu->c_identify(c);
1013 
1014         /* Clear/Set all flags overridden by options, after probe */
1015         for (i = 0; i < NCAPINTS; i++) {
1016                 c->x86_capability[i] &= ~cpu_caps_cleared[i];
1017                 c->x86_capability[i] |= cpu_caps_set[i];
1018         }
1019 
1020 #ifdef CONFIG_X86_64
1021         c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
1022 #endif
1023 
1024         /*
1025          * Vendor-specific initialization.  In this section we
1026          * canonicalize the feature flags, meaning if there are
1027          * features a certain CPU supports which CPUID doesn't
1028          * tell us, CPUID claiming incorrect flags, or other bugs,
1029          * we handle them here.
1030          *
1031          * At the end of this section, c->x86_capability better
1032          * indicate the features this CPU genuinely supports!
1033          */
1034         if (this_cpu->c_init)
1035                 this_cpu->c_init(c);
1036 
1037         /* Disable the PN if appropriate */
1038         squash_the_stupid_serial_number(c);
1039 
1040         /* Set up SMEP/SMAP */
1041         setup_smep(c);
1042         setup_smap(c);
1043 
1044         /*
1045          * The vendor-specific functions might have changed features.
1046          * Now we do "generic changes."
1047          */
1048 
1049         /* Filter out anything that depends on CPUID levels we don't have */
1050         filter_cpuid_features(c, true);
1051 
1052         /* If the model name is still unset, do table lookup. */
1053         if (!c->x86_model_id[0]) {
1054                 const char *p;
1055                 p = table_lookup_model(c);
1056                 if (p)
1057                         strcpy(c->x86_model_id, p);
1058                 else
1059                         /* Last resort... */
1060                         sprintf(c->x86_model_id, "%02x/%02x",
1061                                 c->x86, c->x86_model);
1062         }
1063 
1064 #ifdef CONFIG_X86_64
1065         detect_ht(c);
1066 #endif
1067 
1068         init_hypervisor(c);
1069         x86_init_rdrand(c);
1070         x86_init_cache_qos(c);
1071         setup_pku(c);
1072 
1073         /*
1074          * Clear/Set all flags overridden by options, need do it
1075          * before following smp all cpus cap AND.
1076          */
1077         for (i = 0; i < NCAPINTS; i++) {
1078                 c->x86_capability[i] &= ~cpu_caps_cleared[i];
1079                 c->x86_capability[i] |= cpu_caps_set[i];
1080         }
1081 
1082         /*
1083          * On SMP, boot_cpu_data holds the common feature set between
1084          * all CPUs; so make sure that we indicate which features are
1085          * common between the CPUs.  The first time this routine gets
1086          * executed, c == &boot_cpu_data.
1087          */
1088         if (c != &boot_cpu_data) {
1089                 /* AND the already accumulated flags with these */
1090                 for (i = 0; i < NCAPINTS; i++)
1091                         boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
1092 
1093                 /* OR, i.e. replicate the bug flags */
1094                 for (i = NCAPINTS; i < NCAPINTS + NBUGINTS; i++)
1095                         c->x86_capability[i] |= boot_cpu_data.x86_capability[i];
1096         }
1097 
1098         /* Init Machine Check Exception if available. */
1099         mcheck_cpu_init(c);
1100 
1101         select_idle_routine(c);
1102 
1103 #ifdef CONFIG_NUMA
1104         numa_add_cpu(smp_processor_id());
1105 #endif
1106         /* The boot/hotplug time assigment got cleared, restore it */
1107         c->logical_proc_id = topology_phys_to_logical_pkg(c->phys_proc_id);
1108 }
1109 
1110 /*
1111  * Set up the CPU state needed to execute SYSENTER/SYSEXIT instructions
1112  * on 32-bit kernels:
1113  */
1114 #ifdef CONFIG_X86_32
1115 void enable_sep_cpu(void)
1116 {
1117         struct tss_struct *tss;
1118         int cpu;
1119 
1120         if (!boot_cpu_has(X86_FEATURE_SEP))
1121                 return;
1122 
1123         cpu = get_cpu();
1124         tss = &per_cpu(cpu_tss, cpu);
1125 
1126         /*
1127          * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
1128          * see the big comment in struct x86_hw_tss's definition.
1129          */
1130 
1131         tss->x86_tss.ss1 = __KERNEL_CS;
1132         wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0);
1133 
1134         wrmsr(MSR_IA32_SYSENTER_ESP,
1135               (unsigned long)tss + offsetofend(struct tss_struct, SYSENTER_stack),
1136               0);
1137 
1138         wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);
1139 
1140         put_cpu();
1141 }
1142 #endif
1143 
1144 void __init identify_boot_cpu(void)
1145 {
1146         identify_cpu(&boot_cpu_data);
1147         init_amd_e400_c1e_mask();
1148 #ifdef CONFIG_X86_32
1149         sysenter_setup();
1150         enable_sep_cpu();
1151 #endif
1152         cpu_detect_tlb(&boot_cpu_data);
1153 }
1154 
1155 void identify_secondary_cpu(struct cpuinfo_x86 *c)
1156 {
1157         BUG_ON(c == &boot_cpu_data);
1158         identify_cpu(c);
1159 #ifdef CONFIG_X86_32
1160         enable_sep_cpu();
1161 #endif
1162         mtrr_ap_init();
1163 }
1164 
1165 struct msr_range {
1166         unsigned        min;
1167         unsigned        max;
1168 };
1169 
1170 static const struct msr_range msr_range_array[] = {
1171         { 0x00000000, 0x00000418},
1172         { 0xc0000000, 0xc000040b},
1173         { 0xc0010000, 0xc0010142},
1174         { 0xc0011000, 0xc001103b},
1175 };
1176 
1177 static void __print_cpu_msr(void)
1178 {
1179         unsigned index_min, index_max;
1180         unsigned index;
1181         u64 val;
1182         int i;
1183 
1184         for (i = 0; i < ARRAY_SIZE(msr_range_array); i++) {
1185                 index_min = msr_range_array[i].min;
1186                 index_max = msr_range_array[i].max;
1187 
1188                 for (index = index_min; index < index_max; index++) {
1189                         if (rdmsrl_safe(index, &val))
1190                                 continue;
1191                         pr_info(" MSR%08x: %016llx\n", index, val);
1192                 }
1193         }
1194 }
1195 
1196 static int show_msr;
1197 
1198 static __init int setup_show_msr(char *arg)
1199 {
1200         int num;
1201 
1202         get_option(&arg, &num);
1203 
1204         if (num > 0)
1205                 show_msr = num;
1206         return 1;
1207 }
1208 __setup("show_msr=", setup_show_msr);
1209 
1210 static __init int setup_noclflush(char *arg)
1211 {
1212         setup_clear_cpu_cap(X86_FEATURE_CLFLUSH);
1213         setup_clear_cpu_cap(X86_FEATURE_CLFLUSHOPT);
1214         return 1;
1215 }
1216 __setup("noclflush", setup_noclflush);
1217 
1218 void print_cpu_info(struct cpuinfo_x86 *c)
1219 {
1220         const char *vendor = NULL;
1221 
1222         if (c->x86_vendor < X86_VENDOR_NUM) {
1223                 vendor = this_cpu->c_vendor;
1224         } else {
1225                 if (c->cpuid_level >= 0)
1226                         vendor = c->x86_vendor_id;
1227         }
1228 
1229         if (vendor && !strstr(c->x86_model_id, vendor))
1230                 pr_cont("%s ", vendor);
1231 
1232         if (c->x86_model_id[0])
1233                 pr_cont("%s", c->x86_model_id);
1234         else
1235                 pr_cont("%d86", c->x86);
1236 
1237         pr_cont(" (family: 0x%x, model: 0x%x", c->x86, c->x86_model);
1238 
1239         if (c->x86_mask || c->cpuid_level >= 0)
1240                 pr_cont(", stepping: 0x%x)\n", c->x86_mask);
1241         else
1242                 pr_cont(")\n");
1243 
1244         print_cpu_msr(c);
1245 }
1246 
1247 void print_cpu_msr(struct cpuinfo_x86 *c)
1248 {
1249         if (c->cpu_index < show_msr)
1250                 __print_cpu_msr();
1251 }
1252 
1253 static __init int setup_disablecpuid(char *arg)
1254 {
1255         int bit;
1256 
1257         if (get_option(&arg, &bit) && bit < NCAPINTS*32)
1258                 setup_clear_cpu_cap(bit);
1259         else
1260                 return 0;
1261 
1262         return 1;
1263 }
1264 __setup("clearcpuid=", setup_disablecpuid);
1265 
1266 #ifdef CONFIG_X86_64
1267 struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
1268 struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1,
1269                                     (unsigned long) debug_idt_table };
1270 
1271 DEFINE_PER_CPU_FIRST(union irq_stack_union,
1272                      irq_stack_union) __aligned(PAGE_SIZE) __visible;
1273 
1274 /*
1275  * The following percpu variables are hot.  Align current_task to
1276  * cacheline size such that they fall in the same cacheline.
1277  */
1278 DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
1279         &init_task;
1280 EXPORT_PER_CPU_SYMBOL(current_task);
1281 
1282 DEFINE_PER_CPU(char *, irq_stack_ptr) =
1283         init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE - 64;
1284 
1285 DEFINE_PER_CPU(unsigned int, irq_count) __visible = -1;
1286 
1287 DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT;
1288 EXPORT_PER_CPU_SYMBOL(__preempt_count);
1289 
1290 /*
1291  * Special IST stacks which the CPU switches to when it calls
1292  * an IST-marked descriptor entry. Up to 7 stacks (hardware
1293  * limit), all of them are 4K, except the debug stack which
1294  * is 8K.
1295  */
1296 static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
1297           [0 ... N_EXCEPTION_STACKS - 1]        = EXCEPTION_STKSZ,
1298           [DEBUG_STACK - 1]                     = DEBUG_STKSZ
1299 };
1300 
1301 static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
1302         [(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]);
1303 
1304 /* May not be marked __init: used by software suspend */
1305 void syscall_init(void)
1306 {
1307         /*
1308          * LSTAR and STAR live in a bit strange symbiosis.
1309          * They both write to the same internal register. STAR allows to
1310          * set CS/DS but only a 32bit target. LSTAR sets the 64bit rip.
1311          */
1312         wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS);
1313         wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64);
1314 
1315 #ifdef CONFIG_IA32_EMULATION
1316         wrmsrl(MSR_CSTAR, (unsigned long)entry_SYSCALL_compat);
1317         /*
1318          * This only works on Intel CPUs.
1319          * On AMD CPUs these MSRs are 32-bit, CPU truncates MSR_IA32_SYSENTER_EIP.
1320          * This does not cause SYSENTER to jump to the wrong location, because
1321          * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit).
1322          */
1323         wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
1324         wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
1325         wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat);
1326 #else
1327         wrmsrl(MSR_CSTAR, (unsigned long)ignore_sysret);
1328         wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG);
1329         wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
1330         wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL);
1331 #endif
1332 
1333         /* Flags to clear on syscall */
1334         wrmsrl(MSR_SYSCALL_MASK,
1335                X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF|
1336                X86_EFLAGS_IOPL|X86_EFLAGS_AC|X86_EFLAGS_NT);
1337 }
1338 
1339 /*
1340  * Copies of the original ist values from the tss are only accessed during
1341  * debugging, no special alignment required.
1342  */
1343 DEFINE_PER_CPU(struct orig_ist, orig_ist);
1344 
1345 static DEFINE_PER_CPU(unsigned long, debug_stack_addr);
1346 DEFINE_PER_CPU(int, debug_stack_usage);
1347 
1348 int is_debug_stack(unsigned long addr)
1349 {
1350         return __this_cpu_read(debug_stack_usage) ||
1351                 (addr <= __this_cpu_read(debug_stack_addr) &&
1352                  addr > (__this_cpu_read(debug_stack_addr) - DEBUG_STKSZ));
1353 }
1354 NOKPROBE_SYMBOL(is_debug_stack);
1355 
1356 DEFINE_PER_CPU(u32, debug_idt_ctr);
1357 
1358 void debug_stack_set_zero(void)
1359 {
1360         this_cpu_inc(debug_idt_ctr);
1361         load_current_idt();
1362 }
1363 NOKPROBE_SYMBOL(debug_stack_set_zero);
1364 
1365 void debug_stack_reset(void)
1366 {
1367         if (WARN_ON(!this_cpu_read(debug_idt_ctr)))
1368                 return;
1369         if (this_cpu_dec_return(debug_idt_ctr) == 0)
1370                 load_current_idt();
1371 }
1372 NOKPROBE_SYMBOL(debug_stack_reset);
1373 
1374 #else   /* CONFIG_X86_64 */
1375 
1376 DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
1377 EXPORT_PER_CPU_SYMBOL(current_task);
1378 DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT;
1379 EXPORT_PER_CPU_SYMBOL(__preempt_count);
1380 
1381 /*
1382  * On x86_32, vm86 modifies tss.sp0, so sp0 isn't a reliable way to find
1383  * the top of the kernel stack.  Use an extra percpu variable to track the
1384  * top of the kernel stack directly.
1385  */
1386 DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) =
1387         (unsigned long)&init_thread_union + THREAD_SIZE;
1388 EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack);
1389 
1390 #ifdef CONFIG_CC_STACKPROTECTOR
1391 DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary);
1392 #endif
1393 
1394 #endif  /* CONFIG_X86_64 */
1395 
1396 /*
1397  * Clear all 6 debug registers:
1398  */
1399 static void clear_all_debug_regs(void)
1400 {
1401         int i;
1402 
1403         for (i = 0; i < 8; i++) {
1404                 /* Ignore db4, db5 */
1405                 if ((i == 4) || (i == 5))
1406                         continue;
1407 
1408                 set_debugreg(0, i);
1409         }
1410 }
1411 
1412 #ifdef CONFIG_KGDB
1413 /*
1414  * Restore debug regs if using kgdbwait and you have a kernel debugger
1415  * connection established.
1416  */
1417 static void dbg_restore_debug_regs(void)
1418 {
1419         if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break))
1420                 arch_kgdb_ops.correct_hw_break();
1421 }
1422 #else /* ! CONFIG_KGDB */
1423 #define dbg_restore_debug_regs()
1424 #endif /* ! CONFIG_KGDB */
1425 
1426 static void wait_for_master_cpu(int cpu)
1427 {
1428 #ifdef CONFIG_SMP
1429         /*
1430          * wait for ACK from master CPU before continuing
1431          * with AP initialization
1432          */
1433         WARN_ON(cpumask_test_and_set_cpu(cpu, cpu_initialized_mask));
1434         while (!cpumask_test_cpu(cpu, cpu_callout_mask))
1435                 cpu_relax();
1436 #endif
1437 }
1438 
1439 /*
1440  * cpu_init() initializes state that is per-CPU. Some data is already
1441  * initialized (naturally) in the bootstrap process, such as the GDT
1442  * and IDT. We reload them nevertheless, this function acts as a
1443  * 'CPU state barrier', nothing should get across.
1444  * A lot of state is already set up in PDA init for 64 bit
1445  */
1446 #ifdef CONFIG_X86_64
1447 
1448 void cpu_init(void)
1449 {
1450         struct orig_ist *oist;
1451         struct task_struct *me;
1452         struct tss_struct *t;
1453         unsigned long v;
1454         int cpu = raw_smp_processor_id();
1455         int i;
1456 
1457         wait_for_master_cpu(cpu);
1458 
1459         /*
1460          * Initialize the CR4 shadow before doing anything that could
1461          * try to read it.
1462          */
1463         cr4_init_shadow();
1464 
1465         /*
1466          * Load microcode on this cpu if a valid microcode is available.
1467          * This is early microcode loading procedure.
1468          */
1469         load_ucode_ap();
1470 
1471         t = &per_cpu(cpu_tss, cpu);
1472         oist = &per_cpu(orig_ist, cpu);
1473 
1474 #ifdef CONFIG_NUMA
1475         if (this_cpu_read(numa_node) == 0 &&
1476             early_cpu_to_node(cpu) != NUMA_NO_NODE)
1477                 set_numa_node(early_cpu_to_node(cpu));
1478 #endif
1479 
1480         me = current;
1481 
1482         pr_debug("Initializing CPU#%d\n", cpu);
1483 
1484         cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
1485 
1486         /*
1487          * Initialize the per-CPU GDT with the boot GDT,
1488          * and set up the GDT descriptor:
1489          */
1490 
1491         switch_to_new_gdt(cpu);
1492         loadsegment(fs, 0);
1493 
1494         load_current_idt();
1495 
1496         memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);
1497         syscall_init();
1498 
1499         wrmsrl(MSR_FS_BASE, 0);
1500         wrmsrl(MSR_KERNEL_GS_BASE, 0);
1501         barrier();
1502 
1503         x86_configure_nx();
1504         x2apic_setup();
1505 
1506         /*
1507          * set up and load the per-CPU TSS
1508          */
1509         if (!oist->ist[0]) {
1510                 char *estacks = per_cpu(exception_stacks, cpu);
1511 
1512                 for (v = 0; v < N_EXCEPTION_STACKS; v++) {
1513                         estacks += exception_stack_sizes[v];
1514                         oist->ist[v] = t->x86_tss.ist[v] =
1515                                         (unsigned long)estacks;
1516                         if (v == DEBUG_STACK-1)
1517                                 per_cpu(debug_stack_addr, cpu) = (unsigned long)estacks;
1518                 }
1519         }
1520 
1521         t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
1522 
1523         /*
1524          * <= is required because the CPU will access up to
1525          * 8 bits beyond the end of the IO permission bitmap.
1526          */
1527         for (i = 0; i <= IO_BITMAP_LONGS; i++)
1528                 t->io_bitmap[i] = ~0UL;
1529 
1530         atomic_inc(&init_mm.mm_count);
1531         me->active_mm = &init_mm;
1532         BUG_ON(me->mm);
1533         enter_lazy_tlb(&init_mm, me);
1534 
1535         load_sp0(t, &current->thread);
1536         set_tss_desc(cpu, t);
1537         load_TR_desc();
1538         load_mm_ldt(&init_mm);
1539 
1540         clear_all_debug_regs();
1541         dbg_restore_debug_regs();
1542 
1543         fpu__init_cpu();
1544 
1545         if (is_uv_system())
1546                 uv_cpu_init();
1547 }
1548 
1549 #else
1550 
1551 void cpu_init(void)
1552 {
1553         int cpu = smp_processor_id();
1554         struct task_struct *curr = current;
1555         struct tss_struct *t = &per_cpu(cpu_tss, cpu);
1556         struct thread_struct *thread = &curr->thread;
1557 
1558         wait_for_master_cpu(cpu);
1559 
1560         /*
1561          * Initialize the CR4 shadow before doing anything that could
1562          * try to read it.
1563          */
1564         cr4_init_shadow();
1565 
1566         show_ucode_info_early();
1567 
1568         pr_info("Initializing CPU#%d\n", cpu);
1569 
1570         if (cpu_feature_enabled(X86_FEATURE_VME) ||
1571             boot_cpu_has(X86_FEATURE_TSC) ||
1572             boot_cpu_has(X86_FEATURE_DE))
1573                 cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
1574 
1575         load_current_idt();
1576         switch_to_new_gdt(cpu);
1577 
1578         /*
1579          * Set up and load the per-CPU TSS and LDT
1580          */
1581         atomic_inc(&init_mm.mm_count);
1582         curr->active_mm = &init_mm;
1583         BUG_ON(curr->mm);
1584         enter_lazy_tlb(&init_mm, curr);
1585 
1586         load_sp0(t, thread);
1587         set_tss_desc(cpu, t);
1588         load_TR_desc();
1589         load_mm_ldt(&init_mm);
1590 
1591         t->x86_tss.io_bitmap_base = offsetof(struct tss_struct, io_bitmap);
1592 
1593 #ifdef CONFIG_DOUBLEFAULT
1594         /* Set up doublefault TSS pointer in the GDT */
1595         __set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
1596 #endif
1597 
1598         clear_all_debug_regs();
1599         dbg_restore_debug_regs();
1600 
1601         fpu__init_cpu();
1602 }
1603 #endif
1604 
1605 static void bsp_resume(void)
1606 {
1607         if (this_cpu->c_bsp_resume)
1608                 this_cpu->c_bsp_resume(&boot_cpu_data);
1609 }
1610 
1611 static struct syscore_ops cpu_syscore_ops = {
1612         .resume         = bsp_resume,
1613 };
1614 
1615 static int __init init_cpu_syscore(void)
1616 {
1617         register_syscore_ops(&cpu_syscore_ops);
1618         return 0;
1619 }
1620 core_initcall(init_cpu_syscore);
1621 

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