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>
51 #ifdef CONFIG_X86_LOCAL_APIC
52 #include <asm/uv/uv.h>
57 u32 elf_hwcap2 __read_mostly
;
59 /* all of these masks are initialized in setup_cpu_local_masks() */
60 cpumask_var_t cpu_initialized_mask
;
61 cpumask_var_t cpu_callout_mask
;
62 cpumask_var_t cpu_callin_mask
;
64 /* representing cpus for which sibling maps can be computed */
65 cpumask_var_t cpu_sibling_setup_mask
;
67 /* correctly size the local cpu masks */
68 void __init
setup_cpu_local_masks(void)
70 alloc_bootmem_cpumask_var(&cpu_initialized_mask
);
71 alloc_bootmem_cpumask_var(&cpu_callin_mask
);
72 alloc_bootmem_cpumask_var(&cpu_callout_mask
);
73 alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask
);
76 static void default_init(struct cpuinfo_x86
*c
)
79 cpu_detect_cache_sizes(c
);
81 /* Not much we can do here... */
82 /* Check if at least it has cpuid */
83 if (c
->cpuid_level
== -1) {
84 /* No cpuid. It must be an ancient CPU */
86 strcpy(c
->x86_model_id
, "486");
88 strcpy(c
->x86_model_id
, "386");
93 static const struct cpu_dev default_cpu
= {
94 .c_init
= default_init
,
95 .c_vendor
= "Unknown",
96 .c_x86_vendor
= X86_VENDOR_UNKNOWN
,
99 static const struct cpu_dev
*this_cpu
= &default_cpu
;
101 DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page
, gdt_page
) = { .gdt
= {
104 * We need valid kernel segments for data and code in long mode too
105 * IRET will check the segment types kkeil 2000/10/28
106 * Also sysret mandates a special GDT layout
108 * TLS descriptors are currently at a different place compared to i386.
109 * Hopefully nobody expects them at a fixed place (Wine?)
111 [GDT_ENTRY_KERNEL32_CS
] = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff),
112 [GDT_ENTRY_KERNEL_CS
] = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff),
113 [GDT_ENTRY_KERNEL_DS
] = GDT_ENTRY_INIT(0xc093, 0, 0xfffff),
114 [GDT_ENTRY_DEFAULT_USER32_CS
] = GDT_ENTRY_INIT(0xc0fb, 0, 0xfffff),
115 [GDT_ENTRY_DEFAULT_USER_DS
] = GDT_ENTRY_INIT(0xc0f3, 0, 0xfffff),
116 [GDT_ENTRY_DEFAULT_USER_CS
] = GDT_ENTRY_INIT(0xa0fb, 0, 0xfffff),
118 [GDT_ENTRY_KERNEL_CS
] = GDT_ENTRY_INIT(0xc09a, 0, 0xfffff),
119 [GDT_ENTRY_KERNEL_DS
] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
120 [GDT_ENTRY_DEFAULT_USER_CS
] = GDT_ENTRY_INIT(0xc0fa, 0, 0xfffff),
121 [GDT_ENTRY_DEFAULT_USER_DS
] = GDT_ENTRY_INIT(0xc0f2, 0, 0xfffff),
123 * Segments used for calling PnP BIOS have byte granularity.
124 * They code segments and data segments have fixed 64k limits,
125 * the transfer segment sizes are set at run time.
128 [GDT_ENTRY_PNPBIOS_CS32
] = GDT_ENTRY_INIT(0x409a, 0, 0xffff),
130 [GDT_ENTRY_PNPBIOS_CS16
] = GDT_ENTRY_INIT(0x009a, 0, 0xffff),
132 [GDT_ENTRY_PNPBIOS_DS
] = GDT_ENTRY_INIT(0x0092, 0, 0xffff),
134 [GDT_ENTRY_PNPBIOS_TS1
] = GDT_ENTRY_INIT(0x0092, 0, 0),
136 [GDT_ENTRY_PNPBIOS_TS2
] = GDT_ENTRY_INIT(0x0092, 0, 0),
138 * The APM segments have byte granularity and their bases
139 * are set at run time. All have 64k limits.
142 [GDT_ENTRY_APMBIOS_BASE
] = GDT_ENTRY_INIT(0x409a, 0, 0xffff),
144 [GDT_ENTRY_APMBIOS_BASE
+1] = GDT_ENTRY_INIT(0x009a, 0, 0xffff),
146 [GDT_ENTRY_APMBIOS_BASE
+2] = GDT_ENTRY_INIT(0x4092, 0, 0xffff),
148 [GDT_ENTRY_ESPFIX_SS
] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
149 [GDT_ENTRY_PERCPU
] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
150 GDT_STACK_CANARY_INIT
153 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page
);
155 static int __init
x86_mpx_setup(char *s
)
157 /* require an exact match without trailing characters */
161 /* do not emit a message if the feature is not present */
162 if (!boot_cpu_has(X86_FEATURE_MPX
))
165 setup_clear_cpu_cap(X86_FEATURE_MPX
);
166 pr_info("nompx: Intel Memory Protection Extensions (MPX) disabled\n");
169 __setup("nompx", x86_mpx_setup
);
172 static int __init
x86_nopcid_setup(char *s
)
174 /* nopcid doesn't accept parameters */
178 /* do not emit a message if the feature is not present */
179 if (!boot_cpu_has(X86_FEATURE_PCID
))
182 setup_clear_cpu_cap(X86_FEATURE_PCID
);
183 pr_info("nopcid: PCID feature disabled\n");
186 early_param("nopcid", x86_nopcid_setup
);
189 static int __init
x86_noinvpcid_setup(char *s
)
191 /* noinvpcid doesn't accept parameters */
195 /* do not emit a message if the feature is not present */
196 if (!boot_cpu_has(X86_FEATURE_INVPCID
))
199 setup_clear_cpu_cap(X86_FEATURE_INVPCID
);
200 pr_info("noinvpcid: INVPCID feature disabled\n");
203 early_param("noinvpcid", x86_noinvpcid_setup
);
206 static int cachesize_override
= -1;
207 static int disable_x86_serial_nr
= 1;
209 static int __init
cachesize_setup(char *str
)
211 get_option(&str
, &cachesize_override
);
214 __setup("cachesize=", cachesize_setup
);
216 static int __init
x86_sep_setup(char *s
)
218 setup_clear_cpu_cap(X86_FEATURE_SEP
);
221 __setup("nosep", x86_sep_setup
);
223 /* Standard macro to see if a specific flag is changeable */
224 static inline int flag_is_changeable_p(u32 flag
)
229 * Cyrix and IDT cpus allow disabling of CPUID
230 * so the code below may return different results
231 * when it is executed before and after enabling
232 * the CPUID. Add "volatile" to not allow gcc to
233 * optimize the subsequent calls to this function.
235 asm volatile ("pushfl \n\t"
246 : "=&r" (f1
), "=&r" (f2
)
249 return ((f1
^f2
) & flag
) != 0;
252 /* Probe for the CPUID instruction */
253 int have_cpuid_p(void)
255 return flag_is_changeable_p(X86_EFLAGS_ID
);
258 static void squash_the_stupid_serial_number(struct cpuinfo_x86
*c
)
260 unsigned long lo
, hi
;
262 if (!cpu_has(c
, X86_FEATURE_PN
) || !disable_x86_serial_nr
)
265 /* Disable processor serial number: */
267 rdmsr(MSR_IA32_BBL_CR_CTL
, lo
, hi
);
269 wrmsr(MSR_IA32_BBL_CR_CTL
, lo
, hi
);
271 pr_notice("CPU serial number disabled.\n");
272 clear_cpu_cap(c
, X86_FEATURE_PN
);
274 /* Disabling the serial number may affect the cpuid level */
275 c
->cpuid_level
= cpuid_eax(0);
278 static int __init
x86_serial_nr_setup(char *s
)
280 disable_x86_serial_nr
= 0;
283 __setup("serialnumber", x86_serial_nr_setup
);
285 static inline int flag_is_changeable_p(u32 flag
)
289 static inline void squash_the_stupid_serial_number(struct cpuinfo_x86
*c
)
294 static __init
int setup_disable_smep(char *arg
)
296 setup_clear_cpu_cap(X86_FEATURE_SMEP
);
297 /* Check for things that depend on SMEP being enabled: */
298 check_mpx_erratum(&boot_cpu_data
);
301 __setup("nosmep", setup_disable_smep
);
303 static __always_inline
void setup_smep(struct cpuinfo_x86
*c
)
305 if (cpu_has(c
, X86_FEATURE_SMEP
))
306 cr4_set_bits(X86_CR4_SMEP
);
309 static __init
int setup_disable_smap(char *arg
)
311 setup_clear_cpu_cap(X86_FEATURE_SMAP
);
314 __setup("nosmap", setup_disable_smap
);
316 static __always_inline
void setup_smap(struct cpuinfo_x86
*c
)
318 unsigned long eflags
= native_save_fl();
320 /* This should have been cleared long ago */
321 BUG_ON(eflags
& X86_EFLAGS_AC
);
323 if (cpu_has(c
, X86_FEATURE_SMAP
)) {
324 #ifdef CONFIG_X86_SMAP
325 cr4_set_bits(X86_CR4_SMAP
);
327 cr4_clear_bits(X86_CR4_SMAP
);
333 * Protection Keys are not available in 32-bit mode.
335 static bool pku_disabled
;
337 static __always_inline
void setup_pku(struct cpuinfo_x86
*c
)
339 /* check the boot processor, plus compile options for PKU: */
340 if (!cpu_feature_enabled(X86_FEATURE_PKU
))
342 /* checks the actual processor's cpuid bits: */
343 if (!cpu_has(c
, X86_FEATURE_PKU
))
348 cr4_set_bits(X86_CR4_PKE
);
350 * Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE
351 * cpuid bit to be set. We need to ensure that we
352 * update that bit in this CPU's "cpu_info".
357 #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
358 static __init
int setup_disable_pku(char *arg
)
361 * Do not clear the X86_FEATURE_PKU bit. All of the
362 * runtime checks are against OSPKE so clearing the
365 * This way, we will see "pku" in cpuinfo, but not
366 * "ospke", which is exactly what we want. It shows
367 * that the CPU has PKU, but the OS has not enabled it.
368 * This happens to be exactly how a system would look
369 * if we disabled the config option.
371 pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n");
375 __setup("nopku", setup_disable_pku
);
376 #endif /* CONFIG_X86_64 */
379 * Some CPU features depend on higher CPUID levels, which may not always
380 * be available due to CPUID level capping or broken virtualization
381 * software. Add those features to this table to auto-disable them.
383 struct cpuid_dependent_feature
{
388 static const struct cpuid_dependent_feature
389 cpuid_dependent_features
[] = {
390 { X86_FEATURE_MWAIT
, 0x00000005 },
391 { X86_FEATURE_DCA
, 0x00000009 },
392 { X86_FEATURE_XSAVE
, 0x0000000d },
396 static void filter_cpuid_features(struct cpuinfo_x86
*c
, bool warn
)
398 const struct cpuid_dependent_feature
*df
;
400 for (df
= cpuid_dependent_features
; df
->feature
; df
++) {
402 if (!cpu_has(c
, df
->feature
))
405 * Note: cpuid_level is set to -1 if unavailable, but
406 * extended_extended_level is set to 0 if unavailable
407 * and the legitimate extended levels are all negative
408 * when signed; hence the weird messing around with
411 if (!((s32
)df
->level
< 0 ?
412 (u32
)df
->level
> (u32
)c
->extended_cpuid_level
:
413 (s32
)df
->level
> (s32
)c
->cpuid_level
))
416 clear_cpu_cap(c
, df
->feature
);
420 pr_warn("CPU: CPU feature " X86_CAP_FMT
" disabled, no CPUID level 0x%x\n",
421 x86_cap_flag(df
->feature
), df
->level
);
426 * Naming convention should be: <Name> [(<Codename>)]
427 * This table only is used unless init_<vendor>() below doesn't set it;
428 * in particular, if CPUID levels 0x80000002..4 are supported, this
432 /* Look up CPU names by table lookup. */
433 static const char *table_lookup_model(struct cpuinfo_x86
*c
)
436 const struct legacy_cpu_model_info
*info
;
438 if (c
->x86_model
>= 16)
439 return NULL
; /* Range check */
444 info
= this_cpu
->legacy_models
;
446 while (info
->family
) {
447 if (info
->family
== c
->x86
)
448 return info
->model_names
[c
->x86_model
];
452 return NULL
; /* Not found */
455 __u32 cpu_caps_cleared
[NCAPINTS
];
456 __u32 cpu_caps_set
[NCAPINTS
];
458 void load_percpu_segment(int cpu
)
461 loadsegment(fs
, __KERNEL_PERCPU
);
463 __loadsegment_simple(gs
, 0);
464 wrmsrl(MSR_GS_BASE
, (unsigned long)per_cpu(irq_stack_union
.gs_base
, cpu
));
466 load_stack_canary_segment();
469 static void set_percpu_fixmap_pages(int fixmap_index
, void *ptr
,
470 int pages
, pgprot_t prot
)
474 for (i
= 0; i
< pages
; i
++) {
475 __set_fixmap(fixmap_index
- i
,
476 per_cpu_ptr_to_phys(ptr
+ i
* PAGE_SIZE
), prot
);
481 /* The 32-bit entry code needs to find cpu_entry_area. */
482 DEFINE_PER_CPU(struct cpu_entry_area
*, cpu_entry_area
);
485 /* Setup the fixmap mappings only once per-processor */
486 static inline void setup_cpu_entry_area(int cpu
)
489 /* On 64-bit systems, we use a read-only fixmap GDT. */
490 pgprot_t gdt_prot
= PAGE_KERNEL_RO
;
493 * On native 32-bit systems, the GDT cannot be read-only because
494 * our double fault handler uses a task gate, and entering through
495 * a task gate needs to change an available TSS to busy. If the GDT
496 * is read-only, that will triple fault.
498 * On Xen PV, the GDT must be read-only because the hypervisor requires
501 pgprot_t gdt_prot
= boot_cpu_has(X86_FEATURE_XENPV
) ?
502 PAGE_KERNEL_RO
: PAGE_KERNEL
;
505 __set_fixmap(get_cpu_entry_area_index(cpu
, gdt
), get_cpu_gdt_paddr(cpu
), gdt_prot
);
508 * The Intel SDM says (Volume 3, 7.2.1):
510 * Avoid placing a page boundary in the part of the TSS that the
511 * processor reads during a task switch (the first 104 bytes). The
512 * processor may not correctly perform address translations if a
513 * boundary occurs in this area. During a task switch, the processor
514 * reads and writes into the first 104 bytes of each TSS (using
515 * contiguous physical addresses beginning with the physical address
516 * of the first byte of the TSS). So, after TSS access begins, if
517 * part of the 104 bytes is not physically contiguous, the processor
518 * will access incorrect information without generating a page-fault
521 * There are also a lot of errata involving the TSS spanning a page
522 * boundary. Assert that we're not doing that.
524 BUILD_BUG_ON((offsetof(struct tss_struct
, x86_tss
) ^
525 offsetofend(struct tss_struct
, x86_tss
)) & PAGE_MASK
);
526 BUILD_BUG_ON(sizeof(struct tss_struct
) % PAGE_SIZE
!= 0);
527 set_percpu_fixmap_pages(get_cpu_entry_area_index(cpu
, tss
),
528 &per_cpu(cpu_tss
, cpu
),
529 sizeof(struct tss_struct
) / PAGE_SIZE
,
533 this_cpu_write(cpu_entry_area
, get_cpu_entry_area(cpu
));
537 /* Load the original GDT from the per-cpu structure */
538 void load_direct_gdt(int cpu
)
540 struct desc_ptr gdt_descr
;
542 gdt_descr
.address
= (long)get_cpu_gdt_rw(cpu
);
543 gdt_descr
.size
= GDT_SIZE
- 1;
544 load_gdt(&gdt_descr
);
546 EXPORT_SYMBOL_GPL(load_direct_gdt
);
548 /* Load a fixmap remapping of the per-cpu GDT */
549 void load_fixmap_gdt(int cpu
)
551 struct desc_ptr gdt_descr
;
553 gdt_descr
.address
= (long)get_cpu_gdt_ro(cpu
);
554 gdt_descr
.size
= GDT_SIZE
- 1;
555 load_gdt(&gdt_descr
);
557 EXPORT_SYMBOL_GPL(load_fixmap_gdt
);
560 * Current gdt points %fs at the "master" per-cpu area: after this,
561 * it's on the real one.
563 void switch_to_new_gdt(int cpu
)
565 /* Load the original GDT */
566 load_direct_gdt(cpu
);
567 /* Reload the per-cpu base */
568 load_percpu_segment(cpu
);
571 static const struct cpu_dev
*cpu_devs
[X86_VENDOR_NUM
] = {};
573 static void get_model_name(struct cpuinfo_x86
*c
)
578 if (c
->extended_cpuid_level
< 0x80000004)
581 v
= (unsigned int *)c
->x86_model_id
;
582 cpuid(0x80000002, &v
[0], &v
[1], &v
[2], &v
[3]);
583 cpuid(0x80000003, &v
[4], &v
[5], &v
[6], &v
[7]);
584 cpuid(0x80000004, &v
[8], &v
[9], &v
[10], &v
[11]);
585 c
->x86_model_id
[48] = 0;
587 /* Trim whitespace */
588 p
= q
= s
= &c
->x86_model_id
[0];
594 /* Note the last non-whitespace index */
604 void cpu_detect_cache_sizes(struct cpuinfo_x86
*c
)
606 unsigned int n
, dummy
, ebx
, ecx
, edx
, l2size
;
608 n
= c
->extended_cpuid_level
;
610 if (n
>= 0x80000005) {
611 cpuid(0x80000005, &dummy
, &ebx
, &ecx
, &edx
);
612 c
->x86_cache_size
= (ecx
>>24) + (edx
>>24);
614 /* On K8 L1 TLB is inclusive, so don't count it */
619 if (n
< 0x80000006) /* Some chips just has a large L1. */
622 cpuid(0x80000006, &dummy
, &ebx
, &ecx
, &edx
);
626 c
->x86_tlbsize
+= ((ebx
>> 16) & 0xfff) + (ebx
& 0xfff);
628 /* do processor-specific cache resizing */
629 if (this_cpu
->legacy_cache_size
)
630 l2size
= this_cpu
->legacy_cache_size(c
, l2size
);
632 /* Allow user to override all this if necessary. */
633 if (cachesize_override
!= -1)
634 l2size
= cachesize_override
;
637 return; /* Again, no L2 cache is possible */
640 c
->x86_cache_size
= l2size
;
643 u16 __read_mostly tlb_lli_4k
[NR_INFO
];
644 u16 __read_mostly tlb_lli_2m
[NR_INFO
];
645 u16 __read_mostly tlb_lli_4m
[NR_INFO
];
646 u16 __read_mostly tlb_lld_4k
[NR_INFO
];
647 u16 __read_mostly tlb_lld_2m
[NR_INFO
];
648 u16 __read_mostly tlb_lld_4m
[NR_INFO
];
649 u16 __read_mostly tlb_lld_1g
[NR_INFO
];
651 static void cpu_detect_tlb(struct cpuinfo_x86
*c
)
653 if (this_cpu
->c_detect_tlb
)
654 this_cpu
->c_detect_tlb(c
);
656 pr_info("Last level iTLB entries: 4KB %d, 2MB %d, 4MB %d\n",
657 tlb_lli_4k
[ENTRIES
], tlb_lli_2m
[ENTRIES
],
658 tlb_lli_4m
[ENTRIES
]);
660 pr_info("Last level dTLB entries: 4KB %d, 2MB %d, 4MB %d, 1GB %d\n",
661 tlb_lld_4k
[ENTRIES
], tlb_lld_2m
[ENTRIES
],
662 tlb_lld_4m
[ENTRIES
], tlb_lld_1g
[ENTRIES
]);
665 void detect_ht(struct cpuinfo_x86
*c
)
668 u32 eax
, ebx
, ecx
, edx
;
669 int index_msb
, core_bits
;
672 if (!cpu_has(c
, X86_FEATURE_HT
))
675 if (cpu_has(c
, X86_FEATURE_CMP_LEGACY
))
678 if (cpu_has(c
, X86_FEATURE_XTOPOLOGY
))
681 cpuid(1, &eax
, &ebx
, &ecx
, &edx
);
683 smp_num_siblings
= (ebx
& 0xff0000) >> 16;
685 if (smp_num_siblings
== 1) {
686 pr_info_once("CPU0: Hyper-Threading is disabled\n");
690 if (smp_num_siblings
<= 1)
693 index_msb
= get_count_order(smp_num_siblings
);
694 c
->phys_proc_id
= apic
->phys_pkg_id(c
->initial_apicid
, index_msb
);
696 smp_num_siblings
= smp_num_siblings
/ c
->x86_max_cores
;
698 index_msb
= get_count_order(smp_num_siblings
);
700 core_bits
= get_count_order(c
->x86_max_cores
);
702 c
->cpu_core_id
= apic
->phys_pkg_id(c
->initial_apicid
, index_msb
) &
703 ((1 << core_bits
) - 1);
706 if (!printed
&& (c
->x86_max_cores
* smp_num_siblings
) > 1) {
707 pr_info("CPU: Physical Processor ID: %d\n",
709 pr_info("CPU: Processor Core ID: %d\n",
716 static void get_cpu_vendor(struct cpuinfo_x86
*c
)
718 char *v
= c
->x86_vendor_id
;
721 for (i
= 0; i
< X86_VENDOR_NUM
; i
++) {
725 if (!strcmp(v
, cpu_devs
[i
]->c_ident
[0]) ||
726 (cpu_devs
[i
]->c_ident
[1] &&
727 !strcmp(v
, cpu_devs
[i
]->c_ident
[1]))) {
729 this_cpu
= cpu_devs
[i
];
730 c
->x86_vendor
= this_cpu
->c_x86_vendor
;
735 pr_err_once("CPU: vendor_id '%s' unknown, using generic init.\n" \
736 "CPU: Your system may be unstable.\n", v
);
738 c
->x86_vendor
= X86_VENDOR_UNKNOWN
;
739 this_cpu
= &default_cpu
;
742 void cpu_detect(struct cpuinfo_x86
*c
)
744 /* Get vendor name */
745 cpuid(0x00000000, (unsigned int *)&c
->cpuid_level
,
746 (unsigned int *)&c
->x86_vendor_id
[0],
747 (unsigned int *)&c
->x86_vendor_id
[8],
748 (unsigned int *)&c
->x86_vendor_id
[4]);
751 /* Intel-defined flags: level 0x00000001 */
752 if (c
->cpuid_level
>= 0x00000001) {
753 u32 junk
, tfms
, cap0
, misc
;
755 cpuid(0x00000001, &tfms
, &misc
, &junk
, &cap0
);
756 c
->x86
= x86_family(tfms
);
757 c
->x86_model
= x86_model(tfms
);
758 c
->x86_mask
= x86_stepping(tfms
);
760 if (cap0
& (1<<19)) {
761 c
->x86_clflush_size
= ((misc
>> 8) & 0xff) * 8;
762 c
->x86_cache_alignment
= c
->x86_clflush_size
;
767 static void apply_forced_caps(struct cpuinfo_x86
*c
)
771 for (i
= 0; i
< NCAPINTS
; i
++) {
772 c
->x86_capability
[i
] &= ~cpu_caps_cleared
[i
];
773 c
->x86_capability
[i
] |= cpu_caps_set
[i
];
777 void get_cpu_cap(struct cpuinfo_x86
*c
)
779 u32 eax
, ebx
, ecx
, edx
;
781 /* Intel-defined flags: level 0x00000001 */
782 if (c
->cpuid_level
>= 0x00000001) {
783 cpuid(0x00000001, &eax
, &ebx
, &ecx
, &edx
);
785 c
->x86_capability
[CPUID_1_ECX
] = ecx
;
786 c
->x86_capability
[CPUID_1_EDX
] = edx
;
789 /* Thermal and Power Management Leaf: level 0x00000006 (eax) */
790 if (c
->cpuid_level
>= 0x00000006)
791 c
->x86_capability
[CPUID_6_EAX
] = cpuid_eax(0x00000006);
793 /* Additional Intel-defined flags: level 0x00000007 */
794 if (c
->cpuid_level
>= 0x00000007) {
795 cpuid_count(0x00000007, 0, &eax
, &ebx
, &ecx
, &edx
);
796 c
->x86_capability
[CPUID_7_0_EBX
] = ebx
;
797 c
->x86_capability
[CPUID_7_ECX
] = ecx
;
800 /* Extended state features: level 0x0000000d */
801 if (c
->cpuid_level
>= 0x0000000d) {
802 cpuid_count(0x0000000d, 1, &eax
, &ebx
, &ecx
, &edx
);
804 c
->x86_capability
[CPUID_D_1_EAX
] = eax
;
807 /* Additional Intel-defined flags: level 0x0000000F */
808 if (c
->cpuid_level
>= 0x0000000F) {
810 /* QoS sub-leaf, EAX=0Fh, ECX=0 */
811 cpuid_count(0x0000000F, 0, &eax
, &ebx
, &ecx
, &edx
);
812 c
->x86_capability
[CPUID_F_0_EDX
] = edx
;
814 if (cpu_has(c
, X86_FEATURE_CQM_LLC
)) {
815 /* will be overridden if occupancy monitoring exists */
816 c
->x86_cache_max_rmid
= ebx
;
818 /* QoS sub-leaf, EAX=0Fh, ECX=1 */
819 cpuid_count(0x0000000F, 1, &eax
, &ebx
, &ecx
, &edx
);
820 c
->x86_capability
[CPUID_F_1_EDX
] = edx
;
822 if ((cpu_has(c
, X86_FEATURE_CQM_OCCUP_LLC
)) ||
823 ((cpu_has(c
, X86_FEATURE_CQM_MBM_TOTAL
)) ||
824 (cpu_has(c
, X86_FEATURE_CQM_MBM_LOCAL
)))) {
825 c
->x86_cache_max_rmid
= ecx
;
826 c
->x86_cache_occ_scale
= ebx
;
829 c
->x86_cache_max_rmid
= -1;
830 c
->x86_cache_occ_scale
= -1;
834 /* AMD-defined flags: level 0x80000001 */
835 eax
= cpuid_eax(0x80000000);
836 c
->extended_cpuid_level
= eax
;
838 if ((eax
& 0xffff0000) == 0x80000000) {
839 if (eax
>= 0x80000001) {
840 cpuid(0x80000001, &eax
, &ebx
, &ecx
, &edx
);
842 c
->x86_capability
[CPUID_8000_0001_ECX
] = ecx
;
843 c
->x86_capability
[CPUID_8000_0001_EDX
] = edx
;
847 if (c
->extended_cpuid_level
>= 0x80000007) {
848 cpuid(0x80000007, &eax
, &ebx
, &ecx
, &edx
);
850 c
->x86_capability
[CPUID_8000_0007_EBX
] = ebx
;
854 if (c
->extended_cpuid_level
>= 0x80000008) {
855 cpuid(0x80000008, &eax
, &ebx
, &ecx
, &edx
);
857 c
->x86_virt_bits
= (eax
>> 8) & 0xff;
858 c
->x86_phys_bits
= eax
& 0xff;
859 c
->x86_capability
[CPUID_8000_0008_EBX
] = ebx
;
862 else if (cpu_has(c
, X86_FEATURE_PAE
) || cpu_has(c
, X86_FEATURE_PSE36
))
863 c
->x86_phys_bits
= 36;
866 if (c
->extended_cpuid_level
>= 0x8000000a)
867 c
->x86_capability
[CPUID_8000_000A_EDX
] = cpuid_edx(0x8000000a);
869 init_scattered_cpuid_features(c
);
872 * Clear/Set all flags overridden by options, after probe.
873 * This needs to happen each time we re-probe, which may happen
874 * several times during CPU initialization.
876 apply_forced_caps(c
);
879 static void identify_cpu_without_cpuid(struct cpuinfo_x86
*c
)
885 * First of all, decide if this is a 486 or higher
886 * It's a 486 if we can modify the AC flag
888 if (flag_is_changeable_p(X86_EFLAGS_AC
))
893 for (i
= 0; i
< X86_VENDOR_NUM
; i
++)
894 if (cpu_devs
[i
] && cpu_devs
[i
]->c_identify
) {
895 c
->x86_vendor_id
[0] = 0;
896 cpu_devs
[i
]->c_identify(c
);
897 if (c
->x86_vendor_id
[0]) {
906 * Do minimum CPU detection early.
907 * Fields really needed: vendor, cpuid_level, family, model, mask,
909 * The others are not touched to avoid unwanted side effects.
911 * WARNING: this function is only called on the BP. Don't add code here
912 * that is supposed to run on all CPUs.
914 static void __init
early_identify_cpu(struct cpuinfo_x86
*c
)
917 c
->x86_clflush_size
= 64;
918 c
->x86_phys_bits
= 36;
919 c
->x86_virt_bits
= 48;
921 c
->x86_clflush_size
= 32;
922 c
->x86_phys_bits
= 32;
923 c
->x86_virt_bits
= 32;
925 c
->x86_cache_alignment
= c
->x86_clflush_size
;
927 memset(&c
->x86_capability
, 0, sizeof c
->x86_capability
);
928 c
->extended_cpuid_level
= 0;
930 /* cyrix could have cpuid enabled via c_identify()*/
931 if (have_cpuid_p()) {
935 setup_force_cpu_cap(X86_FEATURE_CPUID
);
937 if (this_cpu
->c_early_init
)
938 this_cpu
->c_early_init(c
);
941 filter_cpuid_features(c
, false);
943 if (this_cpu
->c_bsp_init
)
944 this_cpu
->c_bsp_init(c
);
946 identify_cpu_without_cpuid(c
);
947 setup_clear_cpu_cap(X86_FEATURE_CPUID
);
950 setup_force_cpu_cap(X86_FEATURE_ALWAYS
);
955 * Regardless of whether PCID is enumerated, the SDM says
956 * that it can't be enabled in 32-bit mode.
958 setup_clear_cpu_cap(X86_FEATURE_PCID
);
962 void __init
early_cpu_init(void)
964 const struct cpu_dev
*const *cdev
;
967 #ifdef CONFIG_PROCESSOR_SELECT
968 pr_info("KERNEL supported cpus:\n");
971 for (cdev
= __x86_cpu_dev_start
; cdev
< __x86_cpu_dev_end
; cdev
++) {
972 const struct cpu_dev
*cpudev
= *cdev
;
974 if (count
>= X86_VENDOR_NUM
)
976 cpu_devs
[count
] = cpudev
;
979 #ifdef CONFIG_PROCESSOR_SELECT
983 for (j
= 0; j
< 2; j
++) {
984 if (!cpudev
->c_ident
[j
])
986 pr_info(" %s %s\n", cpudev
->c_vendor
,
992 early_identify_cpu(&boot_cpu_data
);
996 * The NOPL instruction is supposed to exist on all CPUs of family >= 6;
997 * unfortunately, that's not true in practice because of early VIA
998 * chips and (more importantly) broken virtualizers that are not easy
999 * to detect. In the latter case it doesn't even *fail* reliably, so
1000 * probing for it doesn't even work. Disable it completely on 32-bit
1001 * unless we can find a reliable way to detect all the broken cases.
1002 * Enable it explicitly on 64-bit for non-constant inputs of cpu_has().
1004 static void detect_nopl(struct cpuinfo_x86
*c
)
1006 #ifdef CONFIG_X86_32
1007 clear_cpu_cap(c
, X86_FEATURE_NOPL
);
1009 set_cpu_cap(c
, X86_FEATURE_NOPL
);
1013 static void detect_null_seg_behavior(struct cpuinfo_x86
*c
)
1015 #ifdef CONFIG_X86_64
1017 * Empirically, writing zero to a segment selector on AMD does
1018 * not clear the base, whereas writing zero to a segment
1019 * selector on Intel does clear the base. Intel's behavior
1020 * allows slightly faster context switches in the common case
1021 * where GS is unused by the prev and next threads.
1023 * Since neither vendor documents this anywhere that I can see,
1024 * detect it directly instead of hardcoding the choice by
1027 * I've designated AMD's behavior as the "bug" because it's
1028 * counterintuitive and less friendly.
1031 unsigned long old_base
, tmp
;
1032 rdmsrl(MSR_FS_BASE
, old_base
);
1033 wrmsrl(MSR_FS_BASE
, 1);
1035 rdmsrl(MSR_FS_BASE
, tmp
);
1037 set_cpu_bug(c
, X86_BUG_NULL_SEG
);
1038 wrmsrl(MSR_FS_BASE
, old_base
);
1042 static void generic_identify(struct cpuinfo_x86
*c
)
1044 c
->extended_cpuid_level
= 0;
1046 if (!have_cpuid_p())
1047 identify_cpu_without_cpuid(c
);
1049 /* cyrix could have cpuid enabled via c_identify()*/
1050 if (!have_cpuid_p())
1059 if (c
->cpuid_level
>= 0x00000001) {
1060 c
->initial_apicid
= (cpuid_ebx(1) >> 24) & 0xFF;
1061 #ifdef CONFIG_X86_32
1063 c
->apicid
= apic
->phys_pkg_id(c
->initial_apicid
, 0);
1065 c
->apicid
= c
->initial_apicid
;
1068 c
->phys_proc_id
= c
->initial_apicid
;
1071 get_model_name(c
); /* Default name */
1075 detect_null_seg_behavior(c
);
1078 * ESPFIX is a strange bug. All real CPUs have it. Paravirt
1079 * systems that run Linux at CPL > 0 may or may not have the
1080 * issue, but, even if they have the issue, there's absolutely
1081 * nothing we can do about it because we can't use the real IRET
1084 * NB: For the time being, only 32-bit kernels support
1085 * X86_BUG_ESPFIX as such. 64-bit kernels directly choose
1086 * whether to apply espfix using paravirt hooks. If any
1087 * non-paravirt system ever shows up that does *not* have the
1088 * ESPFIX issue, we can change this.
1090 #ifdef CONFIG_X86_32
1091 # ifdef CONFIG_PARAVIRT
1093 extern void native_iret(void);
1094 if (pv_cpu_ops
.iret
== native_iret
)
1095 set_cpu_bug(c
, X86_BUG_ESPFIX
);
1098 set_cpu_bug(c
, X86_BUG_ESPFIX
);
1103 static void x86_init_cache_qos(struct cpuinfo_x86
*c
)
1106 * The heavy lifting of max_rmid and cache_occ_scale are handled
1107 * in get_cpu_cap(). Here we just set the max_rmid for the boot_cpu
1108 * in case CQM bits really aren't there in this CPU.
1110 if (c
!= &boot_cpu_data
) {
1111 boot_cpu_data
.x86_cache_max_rmid
=
1112 min(boot_cpu_data
.x86_cache_max_rmid
,
1113 c
->x86_cache_max_rmid
);
1118 * Validate that ACPI/mptables have the same information about the
1119 * effective APIC id and update the package map.
1121 static void validate_apic_and_package_id(struct cpuinfo_x86
*c
)
1124 unsigned int apicid
, cpu
= smp_processor_id();
1126 apicid
= apic
->cpu_present_to_apicid(cpu
);
1128 if (apicid
!= c
->apicid
) {
1129 pr_err(FW_BUG
"CPU%u: APIC id mismatch. Firmware: %x APIC: %x\n",
1130 cpu
, apicid
, c
->initial_apicid
);
1132 BUG_ON(topology_update_package_map(c
->phys_proc_id
, cpu
));
1134 c
->logical_proc_id
= 0;
1139 * This does the hard work of actually picking apart the CPU stuff...
1141 static void identify_cpu(struct cpuinfo_x86
*c
)
1145 c
->loops_per_jiffy
= loops_per_jiffy
;
1146 c
->x86_cache_size
= -1;
1147 c
->x86_vendor
= X86_VENDOR_UNKNOWN
;
1148 c
->x86_model
= c
->x86_mask
= 0; /* So far unknown... */
1149 c
->x86_vendor_id
[0] = '\0'; /* Unset */
1150 c
->x86_model_id
[0] = '\0'; /* Unset */
1151 c
->x86_max_cores
= 1;
1152 c
->x86_coreid_bits
= 0;
1154 #ifdef CONFIG_X86_64
1155 c
->x86_clflush_size
= 64;
1156 c
->x86_phys_bits
= 36;
1157 c
->x86_virt_bits
= 48;
1159 c
->cpuid_level
= -1; /* CPUID not detected */
1160 c
->x86_clflush_size
= 32;
1161 c
->x86_phys_bits
= 32;
1162 c
->x86_virt_bits
= 32;
1164 c
->x86_cache_alignment
= c
->x86_clflush_size
;
1165 memset(&c
->x86_capability
, 0, sizeof c
->x86_capability
);
1167 generic_identify(c
);
1169 if (this_cpu
->c_identify
)
1170 this_cpu
->c_identify(c
);
1172 /* Clear/Set all flags overridden by options, after probe */
1173 apply_forced_caps(c
);
1175 #ifdef CONFIG_X86_64
1176 c
->apicid
= apic
->phys_pkg_id(c
->initial_apicid
, 0);
1180 * Vendor-specific initialization. In this section we
1181 * canonicalize the feature flags, meaning if there are
1182 * features a certain CPU supports which CPUID doesn't
1183 * tell us, CPUID claiming incorrect flags, or other bugs,
1184 * we handle them here.
1186 * At the end of this section, c->x86_capability better
1187 * indicate the features this CPU genuinely supports!
1189 if (this_cpu
->c_init
)
1190 this_cpu
->c_init(c
);
1192 /* Disable the PN if appropriate */
1193 squash_the_stupid_serial_number(c
);
1195 /* Set up SMEP/SMAP */
1200 * The vendor-specific functions might have changed features.
1201 * Now we do "generic changes."
1204 /* Filter out anything that depends on CPUID levels we don't have */
1205 filter_cpuid_features(c
, true);
1207 /* If the model name is still unset, do table lookup. */
1208 if (!c
->x86_model_id
[0]) {
1210 p
= table_lookup_model(c
);
1212 strcpy(c
->x86_model_id
, p
);
1214 /* Last resort... */
1215 sprintf(c
->x86_model_id
, "%02x/%02x",
1216 c
->x86
, c
->x86_model
);
1219 #ifdef CONFIG_X86_64
1224 x86_init_cache_qos(c
);
1228 * Clear/Set all flags overridden by options, need do it
1229 * before following smp all cpus cap AND.
1231 apply_forced_caps(c
);
1234 * On SMP, boot_cpu_data holds the common feature set between
1235 * all CPUs; so make sure that we indicate which features are
1236 * common between the CPUs. The first time this routine gets
1237 * executed, c == &boot_cpu_data.
1239 if (c
!= &boot_cpu_data
) {
1240 /* AND the already accumulated flags with these */
1241 for (i
= 0; i
< NCAPINTS
; i
++)
1242 boot_cpu_data
.x86_capability
[i
] &= c
->x86_capability
[i
];
1244 /* OR, i.e. replicate the bug flags */
1245 for (i
= NCAPINTS
; i
< NCAPINTS
+ NBUGINTS
; i
++)
1246 c
->x86_capability
[i
] |= boot_cpu_data
.x86_capability
[i
];
1249 /* Init Machine Check Exception if available. */
1252 select_idle_routine(c
);
1255 numa_add_cpu(smp_processor_id());
1260 * Set up the CPU state needed to execute SYSENTER/SYSEXIT instructions
1261 * on 32-bit kernels:
1263 #ifdef CONFIG_X86_32
1264 void enable_sep_cpu(void)
1266 struct tss_struct
*tss
;
1269 if (!boot_cpu_has(X86_FEATURE_SEP
))
1273 tss
= &per_cpu(cpu_tss
, cpu
);
1276 * We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
1277 * see the big comment in struct x86_hw_tss's definition.
1280 tss
->x86_tss
.ss1
= __KERNEL_CS
;
1281 wrmsr(MSR_IA32_SYSENTER_CS
, tss
->x86_tss
.ss1
, 0);
1283 wrmsr(MSR_IA32_SYSENTER_ESP
,
1284 (unsigned long)&get_cpu_entry_area(cpu
)->tss
+
1285 offsetofend(struct tss_struct
, SYSENTER_stack
),
1288 wrmsr(MSR_IA32_SYSENTER_EIP
, (unsigned long)entry_SYSENTER_32
, 0);
1294 void __init
identify_boot_cpu(void)
1296 identify_cpu(&boot_cpu_data
);
1297 #ifdef CONFIG_X86_32
1301 cpu_detect_tlb(&boot_cpu_data
);
1304 void identify_secondary_cpu(struct cpuinfo_x86
*c
)
1306 BUG_ON(c
== &boot_cpu_data
);
1308 #ifdef CONFIG_X86_32
1312 validate_apic_and_package_id(c
);
1315 static __init
int setup_noclflush(char *arg
)
1317 setup_clear_cpu_cap(X86_FEATURE_CLFLUSH
);
1318 setup_clear_cpu_cap(X86_FEATURE_CLFLUSHOPT
);
1321 __setup("noclflush", setup_noclflush
);
1323 void print_cpu_info(struct cpuinfo_x86
*c
)
1325 const char *vendor
= NULL
;
1327 if (c
->x86_vendor
< X86_VENDOR_NUM
) {
1328 vendor
= this_cpu
->c_vendor
;
1330 if (c
->cpuid_level
>= 0)
1331 vendor
= c
->x86_vendor_id
;
1334 if (vendor
&& !strstr(c
->x86_model_id
, vendor
))
1335 pr_cont("%s ", vendor
);
1337 if (c
->x86_model_id
[0])
1338 pr_cont("%s", c
->x86_model_id
);
1340 pr_cont("%d86", c
->x86
);
1342 pr_cont(" (family: 0x%x, model: 0x%x", c
->x86
, c
->x86_model
);
1344 if (c
->x86_mask
|| c
->cpuid_level
>= 0)
1345 pr_cont(", stepping: 0x%x)\n", c
->x86_mask
);
1351 * clearcpuid= was already parsed in fpu__init_parse_early_param.
1352 * But we need to keep a dummy __setup around otherwise it would
1353 * show up as an environment variable for init.
1355 static __init
int setup_clearcpuid(char *arg
)
1359 __setup("clearcpuid=", setup_clearcpuid
);
1361 #ifdef CONFIG_X86_64
1362 DEFINE_PER_CPU_FIRST(union irq_stack_union
,
1363 irq_stack_union
) __aligned(PAGE_SIZE
) __visible
;
1366 * The following percpu variables are hot. Align current_task to
1367 * cacheline size such that they fall in the same cacheline.
1369 DEFINE_PER_CPU(struct task_struct
*, current_task
) ____cacheline_aligned
=
1371 EXPORT_PER_CPU_SYMBOL(current_task
);
1373 DEFINE_PER_CPU(char *, irq_stack_ptr
) =
1374 init_per_cpu_var(irq_stack_union
.irq_stack
) + IRQ_STACK_SIZE
;
1376 DEFINE_PER_CPU(unsigned int, irq_count
) __visible
= -1;
1378 DEFINE_PER_CPU(int, __preempt_count
) = INIT_PREEMPT_COUNT
;
1379 EXPORT_PER_CPU_SYMBOL(__preempt_count
);
1382 * Special IST stacks which the CPU switches to when it calls
1383 * an IST-marked descriptor entry. Up to 7 stacks (hardware
1384 * limit), all of them are 4K, except the debug stack which
1387 static const unsigned int exception_stack_sizes
[N_EXCEPTION_STACKS
] = {
1388 [0 ... N_EXCEPTION_STACKS
- 1] = EXCEPTION_STKSZ
,
1389 [DEBUG_STACK
- 1] = DEBUG_STKSZ
1392 static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks
1393 [(N_EXCEPTION_STACKS
- 1) * EXCEPTION_STKSZ
+ DEBUG_STKSZ
]);
1395 /* May not be marked __init: used by software suspend */
1396 void syscall_init(void)
1398 int cpu
= smp_processor_id();
1400 wrmsr(MSR_STAR
, 0, (__USER32_CS
<< 16) | __KERNEL_CS
);
1401 wrmsrl(MSR_LSTAR
, (unsigned long)entry_SYSCALL_64
);
1403 #ifdef CONFIG_IA32_EMULATION
1404 wrmsrl(MSR_CSTAR
, (unsigned long)entry_SYSCALL_compat
);
1406 * This only works on Intel CPUs.
1407 * On AMD CPUs these MSRs are 32-bit, CPU truncates MSR_IA32_SYSENTER_EIP.
1408 * This does not cause SYSENTER to jump to the wrong location, because
1409 * AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit).
1411 wrmsrl_safe(MSR_IA32_SYSENTER_CS
, (u64
)__KERNEL_CS
);
1412 wrmsrl_safe(MSR_IA32_SYSENTER_ESP
,
1413 (unsigned long)&get_cpu_entry_area(cpu
)->tss
+
1414 offsetofend(struct tss_struct
, SYSENTER_stack
));
1415 wrmsrl_safe(MSR_IA32_SYSENTER_EIP
, (u64
)entry_SYSENTER_compat
);
1417 wrmsrl(MSR_CSTAR
, (unsigned long)ignore_sysret
);
1418 wrmsrl_safe(MSR_IA32_SYSENTER_CS
, (u64
)GDT_ENTRY_INVALID_SEG
);
1419 wrmsrl_safe(MSR_IA32_SYSENTER_ESP
, 0ULL);
1420 wrmsrl_safe(MSR_IA32_SYSENTER_EIP
, 0ULL);
1423 /* Flags to clear on syscall */
1424 wrmsrl(MSR_SYSCALL_MASK
,
1425 X86_EFLAGS_TF
|X86_EFLAGS_DF
|X86_EFLAGS_IF
|
1426 X86_EFLAGS_IOPL
|X86_EFLAGS_AC
|X86_EFLAGS_NT
);
1430 * Copies of the original ist values from the tss are only accessed during
1431 * debugging, no special alignment required.
1433 DEFINE_PER_CPU(struct orig_ist
, orig_ist
);
1435 static DEFINE_PER_CPU(unsigned long, debug_stack_addr
);
1436 DEFINE_PER_CPU(int, debug_stack_usage
);
1438 int is_debug_stack(unsigned long addr
)
1440 return __this_cpu_read(debug_stack_usage
) ||
1441 (addr
<= __this_cpu_read(debug_stack_addr
) &&
1442 addr
> (__this_cpu_read(debug_stack_addr
) - DEBUG_STKSZ
));
1444 NOKPROBE_SYMBOL(is_debug_stack
);
1446 DEFINE_PER_CPU(u32
, debug_idt_ctr
);
1448 void debug_stack_set_zero(void)
1450 this_cpu_inc(debug_idt_ctr
);
1453 NOKPROBE_SYMBOL(debug_stack_set_zero
);
1455 void debug_stack_reset(void)
1457 if (WARN_ON(!this_cpu_read(debug_idt_ctr
)))
1459 if (this_cpu_dec_return(debug_idt_ctr
) == 0)
1462 NOKPROBE_SYMBOL(debug_stack_reset
);
1464 #else /* CONFIG_X86_64 */
1466 DEFINE_PER_CPU(struct task_struct
*, current_task
) = &init_task
;
1467 EXPORT_PER_CPU_SYMBOL(current_task
);
1468 DEFINE_PER_CPU(int, __preempt_count
) = INIT_PREEMPT_COUNT
;
1469 EXPORT_PER_CPU_SYMBOL(__preempt_count
);
1472 * On x86_32, vm86 modifies tss.sp0, so sp0 isn't a reliable way to find
1473 * the top of the kernel stack. Use an extra percpu variable to track the
1474 * top of the kernel stack directly.
1476 DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack
) =
1477 (unsigned long)&init_thread_union
+ THREAD_SIZE
;
1478 EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack
);
1480 #ifdef CONFIG_CC_STACKPROTECTOR
1481 DEFINE_PER_CPU_ALIGNED(struct stack_canary
, stack_canary
);
1484 #endif /* CONFIG_X86_64 */
1487 * Clear all 6 debug registers:
1489 static void clear_all_debug_regs(void)
1493 for (i
= 0; i
< 8; i
++) {
1494 /* Ignore db4, db5 */
1495 if ((i
== 4) || (i
== 5))
1504 * Restore debug regs if using kgdbwait and you have a kernel debugger
1505 * connection established.
1507 static void dbg_restore_debug_regs(void)
1509 if (unlikely(kgdb_connected
&& arch_kgdb_ops
.correct_hw_break
))
1510 arch_kgdb_ops
.correct_hw_break();
1512 #else /* ! CONFIG_KGDB */
1513 #define dbg_restore_debug_regs()
1514 #endif /* ! CONFIG_KGDB */
1516 static void wait_for_master_cpu(int cpu
)
1520 * wait for ACK from master CPU before continuing
1521 * with AP initialization
1523 WARN_ON(cpumask_test_and_set_cpu(cpu
, cpu_initialized_mask
));
1524 while (!cpumask_test_cpu(cpu
, cpu_callout_mask
))
1530 * cpu_init() initializes state that is per-CPU. Some data is already
1531 * initialized (naturally) in the bootstrap process, such as the GDT
1532 * and IDT. We reload them nevertheless, this function acts as a
1533 * 'CPU state barrier', nothing should get across.
1534 * A lot of state is already set up in PDA init for 64 bit
1536 #ifdef CONFIG_X86_64
1540 struct orig_ist
*oist
;
1541 struct task_struct
*me
;
1542 struct tss_struct
*t
;
1544 int cpu
= raw_smp_processor_id();
1547 wait_for_master_cpu(cpu
);
1550 * Initialize the CR4 shadow before doing anything that could
1558 t
= &per_cpu(cpu_tss
, cpu
);
1559 oist
= &per_cpu(orig_ist
, cpu
);
1562 if (this_cpu_read(numa_node
) == 0 &&
1563 early_cpu_to_node(cpu
) != NUMA_NO_NODE
)
1564 set_numa_node(early_cpu_to_node(cpu
));
1569 pr_debug("Initializing CPU#%d\n", cpu
);
1571 cr4_clear_bits(X86_CR4_VME
|X86_CR4_PVI
|X86_CR4_TSD
|X86_CR4_DE
);
1574 * Initialize the per-CPU GDT with the boot GDT,
1575 * and set up the GDT descriptor:
1578 switch_to_new_gdt(cpu
);
1583 memset(me
->thread
.tls_array
, 0, GDT_ENTRY_TLS_ENTRIES
* 8);
1586 wrmsrl(MSR_FS_BASE
, 0);
1587 wrmsrl(MSR_KERNEL_GS_BASE
, 0);
1594 * set up and load the per-CPU TSS
1596 if (!oist
->ist
[0]) {
1597 char *estacks
= per_cpu(exception_stacks
, cpu
);
1599 for (v
= 0; v
< N_EXCEPTION_STACKS
; v
++) {
1600 estacks
+= exception_stack_sizes
[v
];
1601 oist
->ist
[v
] = t
->x86_tss
.ist
[v
] =
1602 (unsigned long)estacks
;
1603 if (v
== DEBUG_STACK
-1)
1604 per_cpu(debug_stack_addr
, cpu
) = (unsigned long)estacks
;
1608 t
->x86_tss
.io_bitmap_base
= IO_BITMAP_OFFSET
;
1611 * <= is required because the CPU will access up to
1612 * 8 bits beyond the end of the IO permission bitmap.
1614 for (i
= 0; i
<= IO_BITMAP_LONGS
; i
++)
1615 t
->io_bitmap
[i
] = ~0UL;
1618 me
->active_mm
= &init_mm
;
1620 initialize_tlbstate_and_flush();
1621 enter_lazy_tlb(&init_mm
, me
);
1623 setup_cpu_entry_area(cpu
);
1626 * Initialize the TSS. sp0 points to the entry trampoline stack
1627 * regardless of what task is running.
1629 set_tss_desc(cpu
, &get_cpu_entry_area(cpu
)->tss
.x86_tss
);
1631 load_sp0((unsigned long)&get_cpu_entry_area(cpu
)->tss
+
1632 offsetofend(struct tss_struct
, SYSENTER_stack
));
1634 load_mm_ldt(&init_mm
);
1636 clear_all_debug_regs();
1637 dbg_restore_debug_regs();
1644 load_fixmap_gdt(cpu
);
1651 int cpu
= smp_processor_id();
1652 struct task_struct
*curr
= current
;
1653 struct tss_struct
*t
= &per_cpu(cpu_tss
, cpu
);
1655 wait_for_master_cpu(cpu
);
1658 * Initialize the CR4 shadow before doing anything that could
1663 show_ucode_info_early();
1665 pr_info("Initializing CPU#%d\n", cpu
);
1667 if (cpu_feature_enabled(X86_FEATURE_VME
) ||
1668 boot_cpu_has(X86_FEATURE_TSC
) ||
1669 boot_cpu_has(X86_FEATURE_DE
))
1670 cr4_clear_bits(X86_CR4_VME
|X86_CR4_PVI
|X86_CR4_TSD
|X86_CR4_DE
);
1673 switch_to_new_gdt(cpu
);
1676 * Set up and load the per-CPU TSS and LDT
1679 curr
->active_mm
= &init_mm
;
1681 initialize_tlbstate_and_flush();
1682 enter_lazy_tlb(&init_mm
, curr
);
1684 setup_cpu_entry_area(cpu
);
1687 * Initialize the TSS. Don't bother initializing sp0, as the initial
1688 * task never enters user mode.
1690 set_tss_desc(cpu
, &get_cpu_entry_area(cpu
)->tss
.x86_tss
);
1693 load_mm_ldt(&init_mm
);
1695 t
->x86_tss
.io_bitmap_base
= IO_BITMAP_OFFSET
;
1697 #ifdef CONFIG_DOUBLEFAULT
1698 /* Set up doublefault TSS pointer in the GDT */
1699 __set_tss_desc(cpu
, GDT_ENTRY_DOUBLEFAULT_TSS
, &doublefault_tss
);
1702 clear_all_debug_regs();
1703 dbg_restore_debug_regs();
1707 load_fixmap_gdt(cpu
);
1711 static void bsp_resume(void)
1713 if (this_cpu
->c_bsp_resume
)
1714 this_cpu
->c_bsp_resume(&boot_cpu_data
);
1717 static struct syscore_ops cpu_syscore_ops
= {
1718 .resume
= bsp_resume
,
1721 static int __init
init_cpu_syscore(void)
1723 register_syscore_ops(&cpu_syscore_ops
);
1726 core_initcall(init_cpu_syscore
);