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/mm.h>
11 #include <linux/sched/clock.h>
12 #include <linux/sched/task.h>
13 #include <linux/init.h>
14 #include <linux/kprobes.h>
15 #include <linux/kgdb.h>
16 #include <linux/smp.h>
18 #include <linux/syscore_ops.h>
20 #include <asm/stackprotector.h>
21 #include <asm/perf_event.h>
22 #include <asm/mmu_context.h>
23 #include <asm/archrandom.h>
24 #include <asm/hypervisor.h>
25 #include <asm/processor.h>
26 #include <asm/tlbflush.h>
27 #include <asm/debugreg.h>
28 #include <asm/sections.h>
29 #include <asm/vsyscall.h>
30 #include <linux/topology.h>
31 #include <linux/cpumask.h>
32 #include <asm/pgtable.h>
33 #include <linux/atomic.h>
34 #include <asm/proto.h>
35 #include <asm/setup.h>
38 #include <asm/fpu/internal.h>
40 #include <asm/hwcap2.h>
41 #include <linux/numa.h>
48 #include <asm/microcode.h>
49 #include <asm/microcode_intel.h>
50 #include <asm/intel-family.h>
51 #include <asm/cpu_device_id.h>
53 #ifdef CONFIG_X86_LOCAL_APIC
54 #include <asm/uv/uv.h>
59 u32 elf_hwcap2 __read_mostly
;
61 /* all of these masks are initialized in setup_cpu_local_masks() */
62 cpumask_var_t cpu_initialized_mask
;
63 cpumask_var_t cpu_callout_mask
;
64 cpumask_var_t cpu_callin_mask
;
66 /* representing cpus for which sibling maps can be computed */
67 cpumask_var_t cpu_sibling_setup_mask
;
69 /* Number of siblings per CPU package */
70 int smp_num_siblings
= 1;
71 EXPORT_SYMBOL(smp_num_siblings
);
73 /* Last level cache ID of each logical CPU */
74 DEFINE_PER_CPU_READ_MOSTLY(u16
, cpu_llc_id
) = BAD_APICID
;
76 /* correctly size the local cpu masks */
77 void __init
setup_cpu_local_masks(void)
79 alloc_bootmem_cpumask_var(&cpu_initialized_mask
);
80 alloc_bootmem_cpumask_var(&cpu_callin_mask
);
81 alloc_bootmem_cpumask_var(&cpu_callout_mask
);
82 alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask
);
85 static void default_init(struct cpuinfo_x86
*c
)
88 cpu_detect_cache_sizes(c
);
90 /* Not much we can do here... */
91 /* Check if at least it has cpuid */
92 if (c
->cpuid_level
== -1) {
93 /* No cpuid. It must be an ancient CPU */
95 strcpy(c
->x86_model_id
, "486");
97 strcpy(c
->x86_model_id
, "386");
102 static const struct cpu_dev default_cpu
= {
103 .c_init
= default_init
,
104 .c_vendor
= "Unknown",
105 .c_x86_vendor
= X86_VENDOR_UNKNOWN
,
108 static const struct cpu_dev
*this_cpu
= &default_cpu
;
110 DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page
, gdt_page
) = { .gdt
= {
113 * We need valid kernel segments for data and code in long mode too
114 * IRET will check the segment types kkeil 2000/10/28
115 * Also sysret mandates a special GDT layout
117 * TLS descriptors are currently at a different place compared to i386.
118 * Hopefully nobody expects them at a fixed place (Wine?)
120 [GDT_ENTRY_KERNEL32_CS
] = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff),
121 [GDT_ENTRY_KERNEL_CS
] = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff),
122 [GDT_ENTRY_KERNEL_DS
] = GDT_ENTRY_INIT(0xc093, 0, 0xfffff),
123 [GDT_ENTRY_DEFAULT_USER32_CS
] = GDT_ENTRY_INIT(0xc0fb, 0, 0xfffff),
124 [GDT_ENTRY_DEFAULT_USER_DS
] = GDT_ENTRY_INIT(0xc0f3, 0, 0xfffff),
125 [GDT_ENTRY_DEFAULT_USER_CS
] = GDT_ENTRY_INIT(0xa0fb, 0, 0xfffff),
127 [GDT_ENTRY_KERNEL_CS
] = GDT_ENTRY_INIT(0xc09a, 0, 0xfffff),
128 [GDT_ENTRY_KERNEL_DS
] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
129 [GDT_ENTRY_DEFAULT_USER_CS
] = GDT_ENTRY_INIT(0xc0fa, 0, 0xfffff),
130 [GDT_ENTRY_DEFAULT_USER_DS
] = GDT_ENTRY_INIT(0xc0f2, 0, 0xfffff),
132 * Segments used for calling PnP BIOS have byte granularity.
133 * They code segments and data segments have fixed 64k limits,
134 * the transfer segment sizes are set at run time.
137 [GDT_ENTRY_PNPBIOS_CS32
] = GDT_ENTRY_INIT(0x409a, 0, 0xffff),
139 [GDT_ENTRY_PNPBIOS_CS16
] = GDT_ENTRY_INIT(0x009a, 0, 0xffff),
141 [GDT_ENTRY_PNPBIOS_DS
] = GDT_ENTRY_INIT(0x0092, 0, 0xffff),
143 [GDT_ENTRY_PNPBIOS_TS1
] = GDT_ENTRY_INIT(0x0092, 0, 0),
145 [GDT_ENTRY_PNPBIOS_TS2
] = GDT_ENTRY_INIT(0x0092, 0, 0),
147 * The APM segments have byte granularity and their bases
148 * are set at run time. All have 64k limits.
151 [GDT_ENTRY_APMBIOS_BASE
] = GDT_ENTRY_INIT(0x409a, 0, 0xffff),
153 [GDT_ENTRY_APMBIOS_BASE
+1] = GDT_ENTRY_INIT(0x009a, 0, 0xffff),
155 [GDT_ENTRY_APMBIOS_BASE
+2] = GDT_ENTRY_INIT(0x4092, 0, 0xffff),
157 [GDT_ENTRY_ESPFIX_SS
] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
158 [GDT_ENTRY_PERCPU
] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
159 GDT_STACK_CANARY_INIT
162 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page
);
164 static int __init
x86_mpx_setup(char *s
)
166 /* require an exact match without trailing characters */
170 /* do not emit a message if the feature is not present */
171 if (!boot_cpu_has(X86_FEATURE_MPX
))
174 setup_clear_cpu_cap(X86_FEATURE_MPX
);
175 pr_info("nompx: Intel Memory Protection Extensions (MPX) disabled\n");
178 __setup("nompx", x86_mpx_setup
);
181 static int __init
x86_nopcid_setup(char *s
)
183 /* nopcid doesn't accept parameters */
187 /* do not emit a message if the feature is not present */
188 if (!boot_cpu_has(X86_FEATURE_PCID
))
191 setup_clear_cpu_cap(X86_FEATURE_PCID
);
192 pr_info("nopcid: PCID feature disabled\n");
195 early_param("nopcid", x86_nopcid_setup
);
198 static int __init
x86_noinvpcid_setup(char *s
)
200 /* noinvpcid doesn't accept parameters */
204 /* do not emit a message if the feature is not present */
205 if (!boot_cpu_has(X86_FEATURE_INVPCID
))
208 setup_clear_cpu_cap(X86_FEATURE_INVPCID
);
209 pr_info("noinvpcid: INVPCID feature disabled\n");
212 early_param("noinvpcid", x86_noinvpcid_setup
);
215 static int cachesize_override
= -1;
216 static int disable_x86_serial_nr
= 1;
218 static int __init
cachesize_setup(char *str
)
220 get_option(&str
, &cachesize_override
);
223 __setup("cachesize=", cachesize_setup
);
225 static int __init
x86_sep_setup(char *s
)
227 setup_clear_cpu_cap(X86_FEATURE_SEP
);
230 __setup("nosep", x86_sep_setup
);
232 /* Standard macro to see if a specific flag is changeable */
233 static inline int flag_is_changeable_p(u32 flag
)
238 * Cyrix and IDT cpus allow disabling of CPUID
239 * so the code below may return different results
240 * when it is executed before and after enabling
241 * the CPUID. Add "volatile" to not allow gcc to
242 * optimize the subsequent calls to this function.
244 asm volatile ("pushfl \n\t"
255 : "=&r" (f1
), "=&r" (f2
)
258 return ((f1
^f2
) & flag
) != 0;
261 /* Probe for the CPUID instruction */
262 int have_cpuid_p(void)
264 return flag_is_changeable_p(X86_EFLAGS_ID
);
267 static void squash_the_stupid_serial_number(struct cpuinfo_x86
*c
)
269 unsigned long lo
, hi
;
271 if (!cpu_has(c
, X86_FEATURE_PN
) || !disable_x86_serial_nr
)
274 /* Disable processor serial number: */
276 rdmsr(MSR_IA32_BBL_CR_CTL
, lo
, hi
);
278 wrmsr(MSR_IA32_BBL_CR_CTL
, lo
, hi
);
280 pr_notice("CPU serial number disabled.\n");
281 clear_cpu_cap(c
, X86_FEATURE_PN
);
283 /* Disabling the serial number may affect the cpuid level */
284 c
->cpuid_level
= cpuid_eax(0);
287 static int __init
x86_serial_nr_setup(char *s
)
289 disable_x86_serial_nr
= 0;
292 __setup("serialnumber", x86_serial_nr_setup
);
294 static inline int flag_is_changeable_p(u32 flag
)
298 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86
*c
)
303 static __init
int setup_disable_smep(char *arg
)
305 setup_clear_cpu_cap(X86_FEATURE_SMEP
);
306 /* Check for things that depend on SMEP being enabled: */
307 check_mpx_erratum(&boot_cpu_data
);
310 __setup("nosmep", setup_disable_smep
);
312 static __always_inline
void setup_smep(struct cpuinfo_x86
*c
)
314 if (cpu_has(c
, X86_FEATURE_SMEP
))
315 cr4_set_bits(X86_CR4_SMEP
);
318 static __init
int setup_disable_smap(char *arg
)
320 setup_clear_cpu_cap(X86_FEATURE_SMAP
);
323 __setup("nosmap", setup_disable_smap
);
325 static __always_inline
void setup_smap(struct cpuinfo_x86
*c
)
327 unsigned long eflags
= native_save_fl();
329 /* This should have been cleared long ago */
330 BUG_ON(eflags
& X86_EFLAGS_AC
);
332 if (cpu_has(c
, X86_FEATURE_SMAP
)) {
333 #ifdef CONFIG_X86_SMAP
334 cr4_set_bits(X86_CR4_SMAP
);
336 cr4_clear_bits(X86_CR4_SMAP
);
341 static __always_inline
void setup_umip(struct cpuinfo_x86
*c
)
343 /* Check the boot processor, plus build option for UMIP. */
344 if (!cpu_feature_enabled(X86_FEATURE_UMIP
))
347 /* Check the current processor's cpuid bits. */
348 if (!cpu_has(c
, X86_FEATURE_UMIP
))
351 cr4_set_bits(X86_CR4_UMIP
);
353 pr_info("x86/cpu: Activated the Intel User Mode Instruction Prevention (UMIP) CPU feature\n");
359 * Make sure UMIP is disabled in case it was enabled in a
360 * previous boot (e.g., via kexec).
362 cr4_clear_bits(X86_CR4_UMIP
);
366 * Protection Keys are not available in 32-bit mode.
368 static bool pku_disabled
;
370 static __always_inline
void setup_pku(struct cpuinfo_x86
*c
)
372 /* check the boot processor, plus compile options for PKU: */
373 if (!cpu_feature_enabled(X86_FEATURE_PKU
))
375 /* checks the actual processor's cpuid bits: */
376 if (!cpu_has(c
, X86_FEATURE_PKU
))
381 cr4_set_bits(X86_CR4_PKE
);
383 * Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE
384 * cpuid bit to be set. We need to ensure that we
385 * update that bit in this CPU's "cpu_info".
390 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
391 static __init
int setup_disable_pku(char *arg
)
394 * Do not clear the X86_FEATURE_PKU bit. All of the
395 * runtime checks are against OSPKE so clearing the
398 * This way, we will see "pku" in cpuinfo, but not
399 * "ospke", which is exactly what we want. It shows
400 * that the CPU has PKU, but the OS has not enabled it.
401 * This happens to be exactly how a system would look
402 * if we disabled the config option.
404 pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n");
408 __setup("nopku", setup_disable_pku
);
409 #endif /* CONFIG_X86_64 */
412 * Some CPU features depend on higher CPUID levels, which may not always
413 * be available due to CPUID level capping or broken virtualization
414 * software. Add those features to this table to auto-disable them.
416 struct cpuid_dependent_feature
{
421 static const struct cpuid_dependent_feature
422 cpuid_dependent_features
[] = {
423 { X86_FEATURE_MWAIT
, 0x00000005 },
424 { X86_FEATURE_DCA
, 0x00000009 },
425 { X86_FEATURE_XSAVE
, 0x0000000d },
429 static void filter_cpuid_features(struct cpuinfo_x86
*c
, bool warn
)
431 const struct cpuid_dependent_feature
*df
;
433 for (df
= cpuid_dependent_features
; df
->feature
; df
++) {
435 if (!cpu_has(c
, df
->feature
))
438 * Note: cpuid_level is set to -1 if unavailable, but
439 * extended_extended_level is set to 0 if unavailable
440 * and the legitimate extended levels are all negative
441 * when signed; hence the weird messing around with
444 if (!((s32
)df
->level
< 0 ?
445 (u32
)df
->level
> (u32
)c
->extended_cpuid_level
:
446 (s32
)df
->level
> (s32
)c
->cpuid_level
))
449 clear_cpu_cap(c
, df
->feature
);
453 pr_warn("CPU: CPU feature " X86_CAP_FMT
" disabled, no CPUID level 0x%x\n",
454 x86_cap_flag(df
->feature
), df
->level
);
459 * Naming convention should be: <Name> [(<Codename>)]
460 * This table only is used unless init_<vendor>() below doesn't set it;
461 * in particular, if CPUID levels 0x80000002..4 are supported, this
465 /* Look up CPU names by table lookup. */
466 static const char *table_lookup_model(struct cpuinfo_x86
*c
)
469 const struct legacy_cpu_model_info
*info
;
471 if (c
->x86_model
>= 16)
472 return NULL
; /* Range check */
477 info
= this_cpu
->legacy_models
;
479 while (info
->family
) {
480 if (info
->family
== c
->x86
)
481 return info
->model_names
[c
->x86_model
];
485 return NULL
; /* Not found */
488 __u32 cpu_caps_cleared
[NCAPINTS
+ NBUGINTS
];
489 __u32 cpu_caps_set
[NCAPINTS
+ NBUGINTS
];
491 void load_percpu_segment(int cpu
)
494 loadsegment(fs
, __KERNEL_PERCPU
);
496 __loadsegment_simple(gs
, 0);
497 wrmsrl(MSR_GS_BASE
, (unsigned long)per_cpu(irq_stack_union
.gs_base
, cpu
));
499 load_stack_canary_segment();
503 /* The 32-bit entry code needs to find cpu_entry_area. */
504 DEFINE_PER_CPU(struct cpu_entry_area
*, cpu_entry_area
);
509 * Special IST stacks which the CPU switches to when it calls
510 * an IST-marked descriptor entry. Up to 7 stacks (hardware
511 * limit), all of them are 4K, except the debug stack which
514 static const unsigned int exception_stack_sizes
[N_EXCEPTION_STACKS
] = {
515 [0 ... N_EXCEPTION_STACKS
- 1] = EXCEPTION_STKSZ
,
516 [DEBUG_STACK
- 1] = DEBUG_STKSZ
520 /* Load the original GDT from the per-cpu structure */
521 void load_direct_gdt(int cpu
)
523 struct desc_ptr gdt_descr
;
525 gdt_descr
.address
= (long)get_cpu_gdt_rw(cpu
);
526 gdt_descr
.size
= GDT_SIZE
- 1;
527 load_gdt(&gdt_descr
);
529 EXPORT_SYMBOL_GPL(load_direct_gdt
);
531 /* Load a fixmap remapping of the per-cpu GDT */
532 void load_fixmap_gdt(int cpu
)
534 struct desc_ptr gdt_descr
;
536 gdt_descr
.address
= (long)get_cpu_gdt_ro(cpu
);
537 gdt_descr
.size
= GDT_SIZE
- 1;
538 load_gdt(&gdt_descr
);
540 EXPORT_SYMBOL_GPL(load_fixmap_gdt
);
543 * Current gdt points %fs at the "master" per-cpu area: after this,
544 * it's on the real one.
546 void switch_to_new_gdt(int cpu
)
548 /* Load the original GDT */
549 load_direct_gdt(cpu
);
550 /* Reload the per-cpu base */
551 load_percpu_segment(cpu
);
554 static const struct cpu_dev
*cpu_devs
[X86_VENDOR_NUM
] = {};
556 static void get_model_name(struct cpuinfo_x86
*c
)
561 if (c
->extended_cpuid_level
< 0x80000004)
564 v
= (unsigned int *)c
->x86_model_id
;
565 cpuid(0x80000002, &v
[0], &v
[1], &v
[2], &v
[3]);
566 cpuid(0x80000003, &v
[4], &v
[5], &v
[6], &v
[7]);
567 cpuid(0x80000004, &v
[8], &v
[9], &v
[10], &v
[11]);
568 c
->x86_model_id
[48] = 0;
570 /* Trim whitespace */
571 p
= q
= s
= &c
->x86_model_id
[0];
577 /* Note the last non-whitespace index */
587 void cpu_detect_cache_sizes(struct cpuinfo_x86
*c
)
589 unsigned int n
, dummy
, ebx
, ecx
, edx
, l2size
;
591 n
= c
->extended_cpuid_level
;
593 if (n
>= 0x80000005) {
594 cpuid(0x80000005, &dummy
, &ebx
, &ecx
, &edx
);
595 c
->x86_cache_size
= (ecx
>>24) + (edx
>>24);
597 /* On K8 L1 TLB is inclusive, so don't count it */
602 if (n
< 0x80000006) /* Some chips just has a large L1. */
605 cpuid(0x80000006, &dummy
, &ebx
, &ecx
, &edx
);
609 c
->x86_tlbsize
+= ((ebx
>> 16) & 0xfff) + (ebx
& 0xfff);
611 /* do processor-specific cache resizing */
612 if (this_cpu
->legacy_cache_size
)
613 l2size
= this_cpu
->legacy_cache_size(c
, l2size
);
615 /* Allow user to override all this if necessary. */
616 if (cachesize_override
!= -1)
617 l2size
= cachesize_override
;
620 return; /* Again, no L2 cache is possible */
623 c
->x86_cache_size
= l2size
;
626 u16 __read_mostly tlb_lli_4k
[NR_INFO
];
627 u16 __read_mostly tlb_lli_2m
[NR_INFO
];
628 u16 __read_mostly tlb_lli_4m
[NR_INFO
];
629 u16 __read_mostly tlb_lld_4k
[NR_INFO
];
630 u16 __read_mostly tlb_lld_2m
[NR_INFO
];
631 u16 __read_mostly tlb_lld_4m
[NR_INFO
];
632 u16 __read_mostly tlb_lld_1g
[NR_INFO
];
634 static void cpu_detect_tlb(struct cpuinfo_x86
*c
)
636 if (this_cpu
->c_detect_tlb
)
637 this_cpu
->c_detect_tlb(c
);
639 pr_info("Last level iTLB entries: 4KB %d, 2MB %d, 4MB %d\n",
640 tlb_lli_4k
[ENTRIES
], tlb_lli_2m
[ENTRIES
],
641 tlb_lli_4m
[ENTRIES
]);
643 pr_info("Last level dTLB entries: 4KB %d, 2MB %d, 4MB %d, 1GB %d\n",
644 tlb_lld_4k
[ENTRIES
], tlb_lld_2m
[ENTRIES
],
645 tlb_lld_4m
[ENTRIES
], tlb_lld_1g
[ENTRIES
]);
648 void detect_ht(struct cpuinfo_x86
*c
)
651 u32 eax
, ebx
, ecx
, edx
;
652 int index_msb
, core_bits
;
655 if (!cpu_has(c
, X86_FEATURE_HT
))
658 if (cpu_has(c
, X86_FEATURE_CMP_LEGACY
))
661 if (cpu_has(c
, X86_FEATURE_XTOPOLOGY
))
664 cpuid(1, &eax
, &ebx
, &ecx
, &edx
);
666 smp_num_siblings
= (ebx
& 0xff0000) >> 16;
668 if (smp_num_siblings
== 1) {
669 pr_info_once("CPU0: Hyper-Threading is disabled\n");
673 if (smp_num_siblings
<= 1)
676 index_msb
= get_count_order(smp_num_siblings
);
677 c
->phys_proc_id
= apic
->phys_pkg_id(c
->initial_apicid
, index_msb
);
679 smp_num_siblings
= smp_num_siblings
/ c
->x86_max_cores
;
681 index_msb
= get_count_order(smp_num_siblings
);
683 core_bits
= get_count_order(c
->x86_max_cores
);
685 c
->cpu_core_id
= apic
->phys_pkg_id(c
->initial_apicid
, index_msb
) &
686 ((1 << core_bits
) - 1);
689 if (!printed
&& (c
->x86_max_cores
* smp_num_siblings
) > 1) {
690 pr_info("CPU: Physical Processor ID: %d\n",
692 pr_info("CPU: Processor Core ID: %d\n",
699 static void get_cpu_vendor(struct cpuinfo_x86
*c
)
701 char *v
= c
->x86_vendor_id
;
704 for (i
= 0; i
< X86_VENDOR_NUM
; i
++) {
708 if (!strcmp(v
, cpu_devs
[i
]->c_ident
[0]) ||
709 (cpu_devs
[i
]->c_ident
[1] &&
710 !strcmp(v
, cpu_devs
[i
]->c_ident
[1]))) {
712 this_cpu
= cpu_devs
[i
];
713 c
->x86_vendor
= this_cpu
->c_x86_vendor
;
718 pr_err_once("CPU: vendor_id '%s' unknown, using generic init.\n" \
719 "CPU: Your system may be unstable.\n", v
);
721 c
->x86_vendor
= X86_VENDOR_UNKNOWN
;
722 this_cpu
= &default_cpu
;
725 void cpu_detect(struct cpuinfo_x86
*c
)
727 /* Get vendor name */
728 cpuid(0x00000000, (unsigned int *)&c
->cpuid_level
,
729 (unsigned int *)&c
->x86_vendor_id
[0],
730 (unsigned int *)&c
->x86_vendor_id
[8],
731 (unsigned int *)&c
->x86_vendor_id
[4]);
734 /* Intel-defined flags: level 0x00000001 */
735 if (c
->cpuid_level
>= 0x00000001) {
736 u32 junk
, tfms
, cap0
, misc
;
738 cpuid(0x00000001, &tfms
, &misc
, &junk
, &cap0
);
739 c
->x86
= x86_family(tfms
);
740 c
->x86_model
= x86_model(tfms
);
741 c
->x86_stepping
= x86_stepping(tfms
);
743 if (cap0
& (1<<19)) {
744 c
->x86_clflush_size
= ((misc
>> 8) & 0xff) * 8;
745 c
->x86_cache_alignment
= c
->x86_clflush_size
;
750 static void apply_forced_caps(struct cpuinfo_x86
*c
)
754 for (i
= 0; i
< NCAPINTS
+ NBUGINTS
; i
++) {
755 c
->x86_capability
[i
] &= ~cpu_caps_cleared
[i
];
756 c
->x86_capability
[i
] |= cpu_caps_set
[i
];
760 static void init_speculation_control(struct cpuinfo_x86
*c
)
763 * The Intel SPEC_CTRL CPUID bit implies IBRS and IBPB support,
764 * and they also have a different bit for STIBP support. Also,
765 * a hypervisor might have set the individual AMD bits even on
766 * Intel CPUs, for finer-grained selection of what's available.
768 if (cpu_has(c
, X86_FEATURE_SPEC_CTRL
)) {
769 set_cpu_cap(c
, X86_FEATURE_IBRS
);
770 set_cpu_cap(c
, X86_FEATURE_IBPB
);
771 set_cpu_cap(c
, X86_FEATURE_MSR_SPEC_CTRL
);
774 if (cpu_has(c
, X86_FEATURE_INTEL_STIBP
))
775 set_cpu_cap(c
, X86_FEATURE_STIBP
);
777 if (cpu_has(c
, X86_FEATURE_SPEC_CTRL_SSBD
) ||
778 cpu_has(c
, X86_FEATURE_VIRT_SSBD
))
779 set_cpu_cap(c
, X86_FEATURE_SSBD
);
781 if (cpu_has(c
, X86_FEATURE_AMD_IBRS
)) {
782 set_cpu_cap(c
, X86_FEATURE_IBRS
);
783 set_cpu_cap(c
, X86_FEATURE_MSR_SPEC_CTRL
);
786 if (cpu_has(c
, X86_FEATURE_AMD_IBPB
))
787 set_cpu_cap(c
, X86_FEATURE_IBPB
);
789 if (cpu_has(c
, X86_FEATURE_AMD_STIBP
)) {
790 set_cpu_cap(c
, X86_FEATURE_STIBP
);
791 set_cpu_cap(c
, X86_FEATURE_MSR_SPEC_CTRL
);
795 void get_cpu_cap(struct cpuinfo_x86
*c
)
797 u32 eax
, ebx
, ecx
, edx
;
799 /* Intel-defined flags: level 0x00000001 */
800 if (c
->cpuid_level
>= 0x00000001) {
801 cpuid(0x00000001, &eax
, &ebx
, &ecx
, &edx
);
803 c
->x86_capability
[CPUID_1_ECX
] = ecx
;
804 c
->x86_capability
[CPUID_1_EDX
] = edx
;
807 /* Thermal and Power Management Leaf: level 0x00000006 (eax) */
808 if (c
->cpuid_level
>= 0x00000006)
809 c
->x86_capability
[CPUID_6_EAX
] = cpuid_eax(0x00000006);
811 /* Additional Intel-defined flags: level 0x00000007 */
812 if (c
->cpuid_level
>= 0x00000007) {
813 cpuid_count(0x00000007, 0, &eax
, &ebx
, &ecx
, &edx
);
814 c
->x86_capability
[CPUID_7_0_EBX
] = ebx
;
815 c
->x86_capability
[CPUID_7_ECX
] = ecx
;
816 c
->x86_capability
[CPUID_7_EDX
] = edx
;
819 /* Extended state features: level 0x0000000d */
820 if (c
->cpuid_level
>= 0x0000000d) {
821 cpuid_count(0x0000000d, 1, &eax
, &ebx
, &ecx
, &edx
);
823 c
->x86_capability
[CPUID_D_1_EAX
] = eax
;
826 /* Additional Intel-defined flags: level 0x0000000F */
827 if (c
->cpuid_level
>= 0x0000000F) {
829 /* QoS sub-leaf, EAX=0Fh, ECX=0 */
830 cpuid_count(0x0000000F, 0, &eax
, &ebx
, &ecx
, &edx
);
831 c
->x86_capability
[CPUID_F_0_EDX
] = edx
;
833 if (cpu_has(c
, X86_FEATURE_CQM_LLC
)) {
834 /* will be overridden if occupancy monitoring exists */
835 c
->x86_cache_max_rmid
= ebx
;
837 /* QoS sub-leaf, EAX=0Fh, ECX=1 */
838 cpuid_count(0x0000000F, 1, &eax
, &ebx
, &ecx
, &edx
);
839 c
->x86_capability
[CPUID_F_1_EDX
] = edx
;
841 if ((cpu_has(c
, X86_FEATURE_CQM_OCCUP_LLC
)) ||
842 ((cpu_has(c
, X86_FEATURE_CQM_MBM_TOTAL
)) ||
843 (cpu_has(c
, X86_FEATURE_CQM_MBM_LOCAL
)))) {
844 c
->x86_cache_max_rmid
= ecx
;
845 c
->x86_cache_occ_scale
= ebx
;
848 c
->x86_cache_max_rmid
= -1;
849 c
->x86_cache_occ_scale
= -1;
853 /* AMD-defined flags: level 0x80000001 */
854 eax
= cpuid_eax(0x80000000);
855 c
->extended_cpuid_level
= eax
;
857 if ((eax
& 0xffff0000) == 0x80000000) {
858 if (eax
>= 0x80000001) {
859 cpuid(0x80000001, &eax
, &ebx
, &ecx
, &edx
);
861 c
->x86_capability
[CPUID_8000_0001_ECX
] = ecx
;
862 c
->x86_capability
[CPUID_8000_0001_EDX
] = edx
;
866 if (c
->extended_cpuid_level
>= 0x80000007) {
867 cpuid(0x80000007, &eax
, &ebx
, &ecx
, &edx
);
869 c
->x86_capability
[CPUID_8000_0007_EBX
] = ebx
;
873 if (c
->extended_cpuid_level
>= 0x80000008) {
874 cpuid(0x80000008, &eax
, &ebx
, &ecx
, &edx
);
876 c
->x86_virt_bits
= (eax
>> 8) & 0xff;
877 c
->x86_phys_bits
= eax
& 0xff;
878 c
->x86_capability
[CPUID_8000_0008_EBX
] = ebx
;
881 else if (cpu_has(c
, X86_FEATURE_PAE
) || cpu_has(c
, X86_FEATURE_PSE36
))
882 c
->x86_phys_bits
= 36;
885 if (c
->extended_cpuid_level
>= 0x8000000a)
886 c
->x86_capability
[CPUID_8000_000A_EDX
] = cpuid_edx(0x8000000a);
888 init_scattered_cpuid_features(c
);
889 init_speculation_control(c
);
892 * Clear/Set all flags overridden by options, after probe.
893 * This needs to happen each time we re-probe, which may happen
894 * several times during CPU initialization.
896 apply_forced_caps(c
);
899 static void identify_cpu_without_cpuid(struct cpuinfo_x86
*c
)
905 * First of all, decide if this is a 486 or higher
906 * It's a 486 if we can modify the AC flag
908 if (flag_is_changeable_p(X86_EFLAGS_AC
))
913 for (i
= 0; i
< X86_VENDOR_NUM
; i
++)
914 if (cpu_devs
[i
] && cpu_devs
[i
]->c_identify
) {
915 c
->x86_vendor_id
[0] = 0;
916 cpu_devs
[i
]->c_identify(c
);
917 if (c
->x86_vendor_id
[0]) {
925 static const __initconst
struct x86_cpu_id cpu_no_speculation
[] = {
926 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_CEDARVIEW
, X86_FEATURE_ANY
},
927 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_CLOVERVIEW
, X86_FEATURE_ANY
},
928 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_LINCROFT
, X86_FEATURE_ANY
},
929 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_PENWELL
, X86_FEATURE_ANY
},
930 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_PINEVIEW
, X86_FEATURE_ANY
},
931 { X86_VENDOR_CENTAUR
, 5 },
932 { X86_VENDOR_INTEL
, 5 },
933 { X86_VENDOR_NSC
, 5 },
934 { X86_VENDOR_ANY
, 4 },
938 static const __initconst
struct x86_cpu_id cpu_no_meltdown
[] = {
943 static const __initconst
struct x86_cpu_id cpu_no_spec_store_bypass
[] = {
944 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_PINEVIEW
},
945 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_LINCROFT
},
946 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_PENWELL
},
947 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_CLOVERVIEW
},
948 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_CEDARVIEW
},
949 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_SILVERMONT1
},
950 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_AIRMONT
},
951 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_SILVERMONT2
},
952 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_ATOM_MERRIFIELD
},
953 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_CORE_YONAH
},
954 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_XEON_PHI_KNL
},
955 { X86_VENDOR_INTEL
, 6, INTEL_FAM6_XEON_PHI_KNM
},
956 { X86_VENDOR_CENTAUR
, 5, },
957 { X86_VENDOR_INTEL
, 5, },
958 { X86_VENDOR_NSC
, 5, },
959 { X86_VENDOR_AMD
, 0x12, },
960 { X86_VENDOR_AMD
, 0x11, },
961 { X86_VENDOR_AMD
, 0x10, },
962 { X86_VENDOR_AMD
, 0xf, },
963 { X86_VENDOR_ANY
, 4, },
967 static void __init
cpu_set_bug_bits(struct cpuinfo_x86
*c
)
971 if (cpu_has(c
, X86_FEATURE_ARCH_CAPABILITIES
))
972 rdmsrl(MSR_IA32_ARCH_CAPABILITIES
, ia32_cap
);
974 if (!x86_match_cpu(cpu_no_spec_store_bypass
) &&
975 !(ia32_cap
& ARCH_CAP_SSB_NO
))
976 setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS
);
978 if (x86_match_cpu(cpu_no_speculation
))
981 setup_force_cpu_bug(X86_BUG_SPECTRE_V1
);
982 setup_force_cpu_bug(X86_BUG_SPECTRE_V2
);
984 if (x86_match_cpu(cpu_no_meltdown
))
987 /* Rogue Data Cache Load? No! */
988 if (ia32_cap
& ARCH_CAP_RDCL_NO
)
991 setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN
);
995 * Do minimum CPU detection early.
996 * Fields really needed: vendor, cpuid_level, family, model, mask,
998 * The others are not touched to avoid unwanted side effects.
1000 * WARNING: this function is only called on the boot CPU. Don't add code
1001 * here that is supposed to run on all CPUs.
1003 static void __init
early_identify_cpu(struct cpuinfo_x86
*c
)
1005 #ifdef CONFIG_X86_64
1006 c
->x86_clflush_size
= 64;
1007 c
->x86_phys_bits
= 36;
1008 c
->x86_virt_bits
= 48;
1010 c
->x86_clflush_size
= 32;
1011 c
->x86_phys_bits
= 32;
1012 c
->x86_virt_bits
= 32;
1014 c
->x86_cache_alignment
= c
->x86_clflush_size
;
1016 memset(&c
->x86_capability
, 0, sizeof c
->x86_capability
);
1017 c
->extended_cpuid_level
= 0;
1019 /* cyrix could have cpuid enabled via c_identify()*/
1020 if (have_cpuid_p()) {
1024 setup_force_cpu_cap(X86_FEATURE_CPUID
);
1026 if (this_cpu
->c_early_init
)
1027 this_cpu
->c_early_init(c
);
1030 filter_cpuid_features(c
, false);
1032 if (this_cpu
->c_bsp_init
)
1033 this_cpu
->c_bsp_init(c
);
1035 identify_cpu_without_cpuid(c
);
1036 setup_clear_cpu_cap(X86_FEATURE_CPUID
);
1039 setup_force_cpu_cap(X86_FEATURE_ALWAYS
);
1041 cpu_set_bug_bits(c
);
1043 fpu__init_system(c
);
1045 #ifdef CONFIG_X86_32
1047 * Regardless of whether PCID is enumerated, the SDM says
1048 * that it can't be enabled in 32-bit mode.
1050 setup_clear_cpu_cap(X86_FEATURE_PCID
);
1054 void __init
early_cpu_init(void)
1056 const struct cpu_dev
*const *cdev
;
1059 #ifdef CONFIG_PROCESSOR_SELECT
1060 pr_info("KERNEL supported cpus:\n");
1063 for (cdev
= __x86_cpu_dev_start
; cdev
< __x86_cpu_dev_end
; cdev
++) {
1064 const struct cpu_dev
*cpudev
= *cdev
;
1066 if (count
>= X86_VENDOR_NUM
)
1068 cpu_devs
[count
] = cpudev
;
1071 #ifdef CONFIG_PROCESSOR_SELECT
1075 for (j
= 0; j
< 2; j
++) {
1076 if (!cpudev
->c_ident
[j
])
1078 pr_info(" %s %s\n", cpudev
->c_vendor
,
1079 cpudev
->c_ident
[j
]);
1084 early_identify_cpu(&boot_cpu_data
);
1088 * The NOPL instruction is supposed to exist on all CPUs of family >= 6;
1089 * unfortunately, that's not true in practice because of early VIA
1090 * chips and (more importantly) broken virtualizers that are not easy
1091 * to detect. In the latter case it doesn't even *fail* reliably, so
1092 * probing for it doesn't even work. Disable it completely on 32-bit
1093 * unless we can find a reliable way to detect all the broken cases.
1094 * Enable it explicitly on 64-bit for non-constant inputs of cpu_has().
1096 static void detect_nopl(struct cpuinfo_x86
*c
)
1098 #ifdef CONFIG_X86_32
1099 clear_cpu_cap(c
, X86_FEATURE_NOPL
);
1101 set_cpu_cap(c
, X86_FEATURE_NOPL
);
1105 static void detect_null_seg_behavior(struct cpuinfo_x86
*c
)
1107 #ifdef CONFIG_X86_64
1109 * Empirically, writing zero to a segment selector on AMD does
1110 * not clear the base, whereas writing zero to a segment
1111 * selector on Intel does clear the base. Intel's behavior
1112 * allows slightly faster context switches in the common case
1113 * where GS is unused by the prev and next threads.
1115 * Since neither vendor documents this anywhere that I can see,
1116 * detect it directly instead of hardcoding the choice by
1119 * I've designated AMD's behavior as the "bug" because it's
1120 * counterintuitive and less friendly.
1123 unsigned long old_base
, tmp
;
1124 rdmsrl(MSR_FS_BASE
, old_base
);
1125 wrmsrl(MSR_FS_BASE
, 1);
1127 rdmsrl(MSR_FS_BASE
, tmp
);
1129 set_cpu_bug(c
, X86_BUG_NULL_SEG
);
1130 wrmsrl(MSR_FS_BASE
, old_base
);
1134 static void generic_identify(struct cpuinfo_x86
*c
)
1136 c
->extended_cpuid_level
= 0;
1138 if (!have_cpuid_p())
1139 identify_cpu_without_cpuid(c
);
1141 /* cyrix could have cpuid enabled via c_identify()*/
1142 if (!have_cpuid_p())
1151 if (c
->cpuid_level
>= 0x00000001) {
1152 c
->initial_apicid
= (cpuid_ebx(1) >> 24) & 0xFF;
1153 #ifdef CONFIG_X86_32
1155 c
->apicid
= apic
->phys_pkg_id(c
->initial_apicid
, 0);
1157 c
->apicid
= c
->initial_apicid
;
1160 c
->phys_proc_id
= c
->initial_apicid
;
1163 get_model_name(c
); /* Default name */
1167 detect_null_seg_behavior(c
);
1170 * ESPFIX is a strange bug. All real CPUs have it. Paravirt
1171 * systems that run Linux at CPL > 0 may or may not have the
1172 * issue, but, even if they have the issue, there's absolutely
1173 * nothing we can do about it because we can't use the real IRET
1176 * NB: For the time being, only 32-bit kernels support
1177 * X86_BUG_ESPFIX as such. 64-bit kernels directly choose
1178 * whether to apply espfix using paravirt hooks. If any
1179 * non-paravirt system ever shows up that does *not* have the
1180 * ESPFIX issue, we can change this.
1182 #ifdef CONFIG_X86_32
1183 # ifdef CONFIG_PARAVIRT
1185 extern void native_iret(void);
1186 if (pv_cpu_ops
.iret
== native_iret
)
1187 set_cpu_bug(c
, X86_BUG_ESPFIX
);
1190 set_cpu_bug(c
, X86_BUG_ESPFIX
);
1195 static void x86_init_cache_qos(struct cpuinfo_x86
*c
)
1198 * The heavy lifting of max_rmid and cache_occ_scale are handled
1199 * in get_cpu_cap(). Here we just set the max_rmid for the boot_cpu
1200 * in case CQM bits really aren't there in this CPU.
1202 if (c
!= &boot_cpu_data
) {
1203 boot_cpu_data
.x86_cache_max_rmid
=
1204 min(boot_cpu_data
.x86_cache_max_rmid
,
1205 c
->x86_cache_max_rmid
);
1210 * Validate that ACPI/mptables have the same information about the
1211 * effective APIC id and update the package map.
1213 static void validate_apic_and_package_id(struct cpuinfo_x86
*c
)
1216 unsigned int apicid
, cpu
= smp_processor_id();
1218 apicid
= apic
->cpu_present_to_apicid(cpu
);
1220 if (apicid
!= c
->apicid
) {
1221 pr_err(FW_BUG
"CPU%u: APIC id mismatch. Firmware: %x APIC: %x\n",
1222 cpu
, apicid
, c
->initial_apicid
);
1224 BUG_ON(topology_update_package_map(c
->phys_proc_id
, cpu
));
1226 c
->logical_proc_id
= 0;
1231 * This does the hard work of actually picking apart the CPU stuff...
1233 static void identify_cpu(struct cpuinfo_x86
*c
)
1237 c
->loops_per_jiffy
= loops_per_jiffy
;
1238 c
->x86_cache_size
= 0;
1239 c
->x86_vendor
= X86_VENDOR_UNKNOWN
;
1240 c
->x86_model
= c
->x86_stepping
= 0; /* So far unknown... */
1241 c
->x86_vendor_id
[0] = '\0'; /* Unset */
1242 c
->x86_model_id
[0] = '\0'; /* Unset */
1243 c
->x86_max_cores
= 1;
1244 c
->x86_coreid_bits
= 0;
1246 #ifdef CONFIG_X86_64
1247 c
->x86_clflush_size
= 64;
1248 c
->x86_phys_bits
= 36;
1249 c
->x86_virt_bits
= 48;
1251 c
->cpuid_level
= -1; /* CPUID not detected */
1252 c
->x86_clflush_size
= 32;
1253 c
->x86_phys_bits
= 32;
1254 c
->x86_virt_bits
= 32;
1256 c
->x86_cache_alignment
= c
->x86_clflush_size
;
1257 memset(&c
->x86_capability
, 0, sizeof c
->x86_capability
);
1259 generic_identify(c
);
1261 if (this_cpu
->c_identify
)
1262 this_cpu
->c_identify(c
);
1264 /* Clear/Set all flags overridden by options, after probe */
1265 apply_forced_caps(c
);
1267 #ifdef CONFIG_X86_64
1268 c
->apicid
= apic
->phys_pkg_id(c
->initial_apicid
, 0);
1272 * Vendor-specific initialization. In this section we
1273 * canonicalize the feature flags, meaning if there are
1274 * features a certain CPU supports which CPUID doesn't
1275 * tell us, CPUID claiming incorrect flags, or other bugs,
1276 * we handle them here.
1278 * At the end of this section, c->x86_capability better
1279 * indicate the features this CPU genuinely supports!
1281 if (this_cpu
->c_init
)
1282 this_cpu
->c_init(c
);
1284 /* Disable the PN if appropriate */
1285 squash_the_stupid_serial_number(c
);
1287 /* Set up SMEP/SMAP/UMIP */
1293 * The vendor-specific functions might have changed features.
1294 * Now we do "generic changes."
1297 /* Filter out anything that depends on CPUID levels we don't have */
1298 filter_cpuid_features(c
, true);
1300 /* If the model name is still unset, do table lookup. */
1301 if (!c
->x86_model_id
[0]) {
1303 p
= table_lookup_model(c
);
1305 strcpy(c
->x86_model_id
, p
);
1307 /* Last resort... */
1308 sprintf(c
->x86_model_id
, "%02x/%02x",
1309 c
->x86
, c
->x86_model
);
1312 #ifdef CONFIG_X86_64
1317 x86_init_cache_qos(c
);
1321 * Clear/Set all flags overridden by options, need do it
1322 * before following smp all cpus cap AND.
1324 apply_forced_caps(c
);
1327 * On SMP, boot_cpu_data holds the common feature set between
1328 * all CPUs; so make sure that we indicate which features are
1329 * common between the CPUs. The first time this routine gets
1330 * executed, c == &boot_cpu_data.
1332 if (c
!= &boot_cpu_data
) {
1333 /* AND the already accumulated flags with these */
1334 for (i
= 0; i
< NCAPINTS
; i
++)
1335 boot_cpu_data
.x86_capability
[i
] &= c
->x86_capability
[i
];
1337 /* OR, i.e. replicate the bug flags */
1338 for (i
= NCAPINTS
; i
< NCAPINTS
+ NBUGINTS
; i
++)
1339 c
->x86_capability
[i
] |= boot_cpu_data
.x86_capability
[i
];
1342 /* Init Machine Check Exception if available. */
1345 select_idle_routine(c
);
1348 numa_add_cpu(smp_processor_id());
1353 * Set up the CPU state needed to execute SYSENTER/SYSEXIT instructions
1354 * on 32-bit kernels:
1356 #ifdef CONFIG_X86_32
1357 void enable_sep_cpu(void)
1359 struct tss_struct
*tss
;
1362 if (!boot_cpu_has(X86_FEATURE_SEP
))
1366 tss
= &per_cpu(cpu_tss_rw
, cpu
);
1369 * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
1370 * see the big comment in struct x86_hw_tss's definition.
1373 tss
->x86_tss
.ss1
= __KERNEL_CS
;
1374 wrmsr(MSR_IA32_SYSENTER_CS
, tss
->x86_tss
.ss1
, 0);
1375 wrmsr(MSR_IA32_SYSENTER_ESP
, (unsigned long)(cpu_entry_stack(cpu
) + 1), 0);
1376 wrmsr(MSR_IA32_SYSENTER_EIP
, (unsigned long)entry_SYSENTER_32
, 0);
1382 void __init
identify_boot_cpu(void)
1384 identify_cpu(&boot_cpu_data
);
1385 #ifdef CONFIG_X86_32
1389 cpu_detect_tlb(&boot_cpu_data
);
1392 void identify_secondary_cpu(struct cpuinfo_x86
*c
)
1394 BUG_ON(c
== &boot_cpu_data
);
1396 #ifdef CONFIG_X86_32
1400 validate_apic_and_package_id(c
);
1401 x86_spec_ctrl_setup_ap();
1404 static __init
int setup_noclflush(char *arg
)
1406 setup_clear_cpu_cap(X86_FEATURE_CLFLUSH
);
1407 setup_clear_cpu_cap(X86_FEATURE_CLFLUSHOPT
);
1410 __setup("noclflush", setup_noclflush
);
1412 void print_cpu_info(struct cpuinfo_x86
*c
)
1414 const char *vendor
= NULL
;
1416 if (c
->x86_vendor
< X86_VENDOR_NUM
) {
1417 vendor
= this_cpu
->c_vendor
;
1419 if (c
->cpuid_level
>= 0)
1420 vendor
= c
->x86_vendor_id
;
1423 if (vendor
&& !strstr(c
->x86_model_id
, vendor
))
1424 pr_cont("%s ", vendor
);
1426 if (c
->x86_model_id
[0])
1427 pr_cont("%s", c
->x86_model_id
);
1429 pr_cont("%d86", c
->x86
);
1431 pr_cont(" (family: 0x%x, model: 0x%x", c
->x86
, c
->x86_model
);
1433 if (c
->x86_stepping
|| c
->cpuid_level
>= 0)
1434 pr_cont(", stepping: 0x%x)\n", c
->x86_stepping
);
1440 * clearcpuid= was already parsed in fpu__init_parse_early_param.
1441 * But we need to keep a dummy __setup around otherwise it would
1442 * show up as an environment variable for init.
1444 static __init
int setup_clearcpuid(char *arg
)
1448 __setup("clearcpuid=", setup_clearcpuid
);
1450 #ifdef CONFIG_X86_64
1451 DEFINE_PER_CPU_FIRST(union irq_stack_union
,
1452 irq_stack_union
) __aligned(PAGE_SIZE
) __visible
;
1455 * The following percpu variables are hot. Align current_task to
1456 * cacheline size such that they fall in the same cacheline.
1458 DEFINE_PER_CPU(struct task_struct
*, current_task
) ____cacheline_aligned
=
1460 EXPORT_PER_CPU_SYMBOL(current_task
);
1462 DEFINE_PER_CPU(char *, irq_stack_ptr
) =
1463 init_per_cpu_var(irq_stack_union
.irq_stack
) + IRQ_STACK_SIZE
;
1465 DEFINE_PER_CPU(unsigned int, irq_count
) __visible
= -1;
1467 DEFINE_PER_CPU(int, __preempt_count
) = INIT_PREEMPT_COUNT
;
1468 EXPORT_PER_CPU_SYMBOL(__preempt_count
);
1470 /* May not be marked __init: used by software suspend */
1471 void syscall_init(void)
1473 extern char _entry_trampoline
[];
1474 extern char entry_SYSCALL_64_trampoline
[];
1476 int cpu
= smp_processor_id();
1477 unsigned long SYSCALL64_entry_trampoline
=
1478 (unsigned long)get_cpu_entry_area(cpu
)->entry_trampoline
+
1479 (entry_SYSCALL_64_trampoline
- _entry_trampoline
);
1481 wrmsr(MSR_STAR
, 0, (__USER32_CS
<< 16) | __KERNEL_CS
);
1482 if (static_cpu_has(X86_FEATURE_PTI
))
1483 wrmsrl(MSR_LSTAR
, SYSCALL64_entry_trampoline
);
1485 wrmsrl(MSR_LSTAR
, (unsigned long)entry_SYSCALL_64
);
1487 #ifdef CONFIG_IA32_EMULATION
1488 wrmsrl(MSR_CSTAR
, (unsigned long)entry_SYSCALL_compat
);
1490 * This only works on Intel CPUs.
1491 * On AMD CPUs these MSRs are 32-bit, CPU truncates MSR_IA32_SYSENTER_EIP.
1492 * This does not cause SYSENTER to jump to the wrong location, because
1493 * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit).
1495 wrmsrl_safe(MSR_IA32_SYSENTER_CS
, (u64
)__KERNEL_CS
);
1496 wrmsrl_safe(MSR_IA32_SYSENTER_ESP
, (unsigned long)(cpu_entry_stack(cpu
) + 1));
1497 wrmsrl_safe(MSR_IA32_SYSENTER_EIP
, (u64
)entry_SYSENTER_compat
);
1499 wrmsrl(MSR_CSTAR
, (unsigned long)ignore_sysret
);
1500 wrmsrl_safe(MSR_IA32_SYSENTER_CS
, (u64
)GDT_ENTRY_INVALID_SEG
);
1501 wrmsrl_safe(MSR_IA32_SYSENTER_ESP
, 0ULL);
1502 wrmsrl_safe(MSR_IA32_SYSENTER_EIP
, 0ULL);
1505 /* Flags to clear on syscall */
1506 wrmsrl(MSR_SYSCALL_MASK
,
1507 X86_EFLAGS_TF
|X86_EFLAGS_DF
|X86_EFLAGS_IF
|
1508 X86_EFLAGS_IOPL
|X86_EFLAGS_AC
|X86_EFLAGS_NT
);
1512 * Copies of the original ist values from the tss are only accessed during
1513 * debugging, no special alignment required.
1515 DEFINE_PER_CPU(struct orig_ist
, orig_ist
);
1517 static DEFINE_PER_CPU(unsigned long, debug_stack_addr
);
1518 DEFINE_PER_CPU(int, debug_stack_usage
);
1520 int is_debug_stack(unsigned long addr
)
1522 return __this_cpu_read(debug_stack_usage
) ||
1523 (addr
<= __this_cpu_read(debug_stack_addr
) &&
1524 addr
> (__this_cpu_read(debug_stack_addr
) - DEBUG_STKSZ
));
1526 NOKPROBE_SYMBOL(is_debug_stack
);
1528 DEFINE_PER_CPU(u32
, debug_idt_ctr
);
1530 void debug_stack_set_zero(void)
1532 this_cpu_inc(debug_idt_ctr
);
1535 NOKPROBE_SYMBOL(debug_stack_set_zero
);
1537 void debug_stack_reset(void)
1539 if (WARN_ON(!this_cpu_read(debug_idt_ctr
)))
1541 if (this_cpu_dec_return(debug_idt_ctr
) == 0)
1544 NOKPROBE_SYMBOL(debug_stack_reset
);
1546 #else /* CONFIG_X86_64 */
1548 DEFINE_PER_CPU(struct task_struct
*, current_task
) = &init_task
;
1549 EXPORT_PER_CPU_SYMBOL(current_task
);
1550 DEFINE_PER_CPU(int, __preempt_count
) = INIT_PREEMPT_COUNT
;
1551 EXPORT_PER_CPU_SYMBOL(__preempt_count
);
1554 * On x86_32, vm86 modifies tss.sp0, so sp0 isn't a reliable way to find
1555 * the top of the kernel stack. Use an extra percpu variable to track the
1556 * top of the kernel stack directly.
1558 DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack
) =
1559 (unsigned long)&init_thread_union
+ THREAD_SIZE
;
1560 EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack
);
1562 #ifdef CONFIG_CC_STACKPROTECTOR
1563 DEFINE_PER_CPU_ALIGNED(struct stack_canary
, stack_canary
);
1566 #endif /* CONFIG_X86_64 */
1569 * Clear all 6 debug registers:
1571 static void clear_all_debug_regs(void)
1575 for (i
= 0; i
< 8; i
++) {
1576 /* Ignore db4, db5 */
1577 if ((i
== 4) || (i
== 5))
1586 * Restore debug regs if using kgdbwait and you have a kernel debugger
1587 * connection established.
1589 static void dbg_restore_debug_regs(void)
1591 if (unlikely(kgdb_connected
&& arch_kgdb_ops
.correct_hw_break
))
1592 arch_kgdb_ops
.correct_hw_break();
1594 #else /* ! CONFIG_KGDB */
1595 #define dbg_restore_debug_regs()
1596 #endif /* ! CONFIG_KGDB */
1598 static void wait_for_master_cpu(int cpu
)
1602 * wait for ACK from master CPU before continuing
1603 * with AP initialization
1605 WARN_ON(cpumask_test_and_set_cpu(cpu
, cpu_initialized_mask
));
1606 while (!cpumask_test_cpu(cpu
, cpu_callout_mask
))
1612 * cpu_init() initializes state that is per-CPU. Some data is already
1613 * initialized (naturally) in the bootstrap process, such as the GDT
1614 * and IDT. We reload them nevertheless, this function acts as a
1615 * 'CPU state barrier', nothing should get across.
1616 * A lot of state is already set up in PDA init for 64 bit
1618 #ifdef CONFIG_X86_64
1622 struct orig_ist
*oist
;
1623 struct task_struct
*me
;
1624 struct tss_struct
*t
;
1626 int cpu
= raw_smp_processor_id();
1629 wait_for_master_cpu(cpu
);
1632 * Initialize the CR4 shadow before doing anything that could
1640 t
= &per_cpu(cpu_tss_rw
, cpu
);
1641 oist
= &per_cpu(orig_ist
, cpu
);
1644 if (this_cpu_read(numa_node
) == 0 &&
1645 early_cpu_to_node(cpu
) != NUMA_NO_NODE
)
1646 set_numa_node(early_cpu_to_node(cpu
));
1651 pr_debug("Initializing CPU#%d\n", cpu
);
1653 cr4_clear_bits(X86_CR4_VME
|X86_CR4_PVI
|X86_CR4_TSD
|X86_CR4_DE
);
1656 * Initialize the per-CPU GDT with the boot GDT,
1657 * and set up the GDT descriptor:
1660 switch_to_new_gdt(cpu
);
1665 memset(me
->thread
.tls_array
, 0, GDT_ENTRY_TLS_ENTRIES
* 8);
1668 wrmsrl(MSR_FS_BASE
, 0);
1669 wrmsrl(MSR_KERNEL_GS_BASE
, 0);
1676 * set up and load the per-CPU TSS
1678 if (!oist
->ist
[0]) {
1679 char *estacks
= get_cpu_entry_area(cpu
)->exception_stacks
;
1681 for (v
= 0; v
< N_EXCEPTION_STACKS
; v
++) {
1682 estacks
+= exception_stack_sizes
[v
];
1683 oist
->ist
[v
] = t
->x86_tss
.ist
[v
] =
1684 (unsigned long)estacks
;
1685 if (v
== DEBUG_STACK
-1)
1686 per_cpu(debug_stack_addr
, cpu
) = (unsigned long)estacks
;
1690 t
->x86_tss
.io_bitmap_base
= IO_BITMAP_OFFSET
;
1693 * <= is required because the CPU will access up to
1694 * 8 bits beyond the end of the IO permission bitmap.
1696 for (i
= 0; i
<= IO_BITMAP_LONGS
; i
++)
1697 t
->io_bitmap
[i
] = ~0UL;
1700 me
->active_mm
= &init_mm
;
1702 initialize_tlbstate_and_flush();
1703 enter_lazy_tlb(&init_mm
, me
);
1706 * Initialize the TSS. sp0 points to the entry trampoline stack
1707 * regardless of what task is running.
1709 set_tss_desc(cpu
, &get_cpu_entry_area(cpu
)->tss
.x86_tss
);
1711 load_sp0((unsigned long)(cpu_entry_stack(cpu
) + 1));
1713 load_mm_ldt(&init_mm
);
1715 clear_all_debug_regs();
1716 dbg_restore_debug_regs();
1723 load_fixmap_gdt(cpu
);
1730 int cpu
= smp_processor_id();
1731 struct task_struct
*curr
= current
;
1732 struct tss_struct
*t
= &per_cpu(cpu_tss_rw
, cpu
);
1734 wait_for_master_cpu(cpu
);
1737 * Initialize the CR4 shadow before doing anything that could
1742 show_ucode_info_early();
1744 pr_info("Initializing CPU#%d\n", cpu
);
1746 if (cpu_feature_enabled(X86_FEATURE_VME
) ||
1747 boot_cpu_has(X86_FEATURE_TSC
) ||
1748 boot_cpu_has(X86_FEATURE_DE
))
1749 cr4_clear_bits(X86_CR4_VME
|X86_CR4_PVI
|X86_CR4_TSD
|X86_CR4_DE
);
1752 switch_to_new_gdt(cpu
);
1755 * Set up and load the per-CPU TSS and LDT
1758 curr
->active_mm
= &init_mm
;
1760 initialize_tlbstate_and_flush();
1761 enter_lazy_tlb(&init_mm
, curr
);
1764 * Initialize the TSS. Don't bother initializing sp0, as the initial
1765 * task never enters user mode.
1767 set_tss_desc(cpu
, &get_cpu_entry_area(cpu
)->tss
.x86_tss
);
1770 load_mm_ldt(&init_mm
);
1772 t
->x86_tss
.io_bitmap_base
= IO_BITMAP_OFFSET
;
1774 #ifdef CONFIG_DOUBLEFAULT
1775 /* Set up doublefault TSS pointer in the GDT */
1776 __set_tss_desc(cpu
, GDT_ENTRY_DOUBLEFAULT_TSS
, &doublefault_tss
);
1779 clear_all_debug_regs();
1780 dbg_restore_debug_regs();
1784 load_fixmap_gdt(cpu
);
1788 static void bsp_resume(void)
1790 if (this_cpu
->c_bsp_resume
)
1791 this_cpu
->c_bsp_resume(&boot_cpu_data
);
1794 static struct syscore_ops cpu_syscore_ops
= {
1795 .resume
= bsp_resume
,
1798 static int __init
init_cpu_syscore(void)
1800 register_syscore_ops(&cpu_syscore_ops
);
1803 core_initcall(init_cpu_syscore
);
1806 * The microcode loader calls this upon late microcode load to recheck features,
1807 * only when microcode has been updated. Caller holds microcode_mutex and CPU
1810 void microcode_check(void)
1812 struct cpuinfo_x86 info
;
1814 perf_check_microcode();
1816 /* Reload CPUID max function as it might've changed. */
1817 info
.cpuid_level
= cpuid_eax(0);
1820 * Copy all capability leafs to pick up the synthetic ones so that
1821 * memcmp() below doesn't fail on that. The ones coming from CPUID will
1822 * get overwritten in get_cpu_cap().
1824 memcpy(&info
.x86_capability
, &boot_cpu_data
.x86_capability
, sizeof(info
.x86_capability
));
1828 if (!memcmp(&info
.x86_capability
, &boot_cpu_data
.x86_capability
, sizeof(info
.x86_capability
)))
1831 pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n");
1832 pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n");