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android-kvm / linux / 3e1a29b3bf66c2850ea8eba78c59c234921c0b69 / . / arch / x86 / kernel / cpu / common.c
blob: 95c8e507580dca469e7ab115b3a70f86d74ed062 [file] [log] [blame]
#include <linux/bootmem.h>
#include <linux/linkage.h>
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/percpu.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/sched/mm.h>
#include <linux/sched/clock.h>
#include <linux/sched/task.h>
#include <linux/init.h>
#include <linux/kprobes.h>
#include <linux/kgdb.h>
#include <linux/smp.h>
#include <linux/io.h>
#include <linux/syscore_ops.h>
#include <asm/stackprotector.h>
#include <asm/perf_event.h>
#include <asm/mmu_context.h>
#include <asm/archrandom.h>
#include <asm/hypervisor.h>
#include <asm/processor.h>
#include <asm/tlbflush.h>
#include <asm/debugreg.h>
#include <asm/sections.h>
#include <asm/vsyscall.h>
#include <linux/topology.h>
#include <linux/cpumask.h>
#include <asm/pgtable.h>
#include <linux/atomic.h>
#include <asm/proto.h>
#include <asm/setup.h>
#include <asm/apic.h>
#include <asm/desc.h>
#include <asm/fpu/internal.h>
#include <asm/mtrr.h>
#include <asm/hwcap2.h>
#include <linux/numa.h>
#include <asm/asm.h>
#include <asm/bugs.h>
#include <asm/cpu.h>
#include <asm/mce.h>
#include <asm/msr.h>
#include <asm/pat.h>
#include <asm/microcode.h>
#include <asm/microcode_intel.h>
#include <asm/intel-family.h>
#include <asm/cpu_device_id.h>
#ifdef CONFIG_X86_LOCAL_APIC
#include <asm/uv/uv.h>
#endif
#include "cpu.h"
u32 elf_hwcap2 __read_mostly;
/* all of these masks are initialized in setup_cpu_local_masks() */
cpumask_var_t cpu_initialized_mask;
cpumask_var_t cpu_callout_mask;
cpumask_var_t cpu_callin_mask;
/* representing cpus for which sibling maps can be computed */
cpumask_var_t cpu_sibling_setup_mask;
/* Number of siblings per CPU package */
int smp_num_siblings = 1;
EXPORT_SYMBOL(smp_num_siblings);
/* Last level cache ID of each logical CPU */
DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id) = BAD_APICID;
/* correctly size the local cpu masks */
void __init setup_cpu_local_masks(void)
{
alloc_bootmem_cpumask_var(&cpu_initialized_mask);
alloc_bootmem_cpumask_var(&cpu_callin_mask);
alloc_bootmem_cpumask_var(&cpu_callout_mask);
alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask);
}
static void default_init(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_64
cpu_detect_cache_sizes(c);
#else
/* Not much we can do here... */
/* Check if at least it has cpuid */
if (c->cpuid_level == -1) {
/* No cpuid. It must be an ancient CPU */
if (c->x86 == 4)
strcpy(c->x86_model_id, "486");
else if (c->x86 == 3)
strcpy(c->x86_model_id, "386");
}
#endif
}
static const struct cpu_dev default_cpu = {
.c_init = default_init,
.c_vendor = "Unknown",
.c_x86_vendor = X86_VENDOR_UNKNOWN,
};
static const struct cpu_dev *this_cpu = &default_cpu;
DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = {
#ifdef CONFIG_X86_64
/*
* We need valid kernel segments for data and code in long mode too
* IRET will check the segment types kkeil 2000/10/28
* Also sysret mandates a special GDT layout
*
* TLS descriptors are currently at a different place compared to i386.
* Hopefully nobody expects them at a fixed place (Wine?)
*/
[GDT_ENTRY_KERNEL32_CS] = GDT_ENTRY_INIT(0xc09b, 0, 0xfffff),
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(0xa09b, 0, 0xfffff),
[GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(0xc093, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER32_CS] = GDT_ENTRY_INIT(0xc0fb, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(0xc0f3, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(0xa0fb, 0, 0xfffff),
#else
[GDT_ENTRY_KERNEL_CS] = GDT_ENTRY_INIT(0xc09a, 0, 0xfffff),
[GDT_ENTRY_KERNEL_DS] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER_CS] = GDT_ENTRY_INIT(0xc0fa, 0, 0xfffff),
[GDT_ENTRY_DEFAULT_USER_DS] = GDT_ENTRY_INIT(0xc0f2, 0, 0xfffff),
/*
* Segments used for calling PnP BIOS have byte granularity.
* They code segments and data segments have fixed 64k limits,
* the transfer segment sizes are set at run time.
*/
/* 32-bit code */
[GDT_ENTRY_PNPBIOS_CS32] = GDT_ENTRY_INIT(0x409a, 0, 0xffff),
/* 16-bit code */
[GDT_ENTRY_PNPBIOS_CS16] = GDT_ENTRY_INIT(0x009a, 0, 0xffff),
/* 16-bit data */
[GDT_ENTRY_PNPBIOS_DS] = GDT_ENTRY_INIT(0x0092, 0, 0xffff),
/* 16-bit data */
[GDT_ENTRY_PNPBIOS_TS1] = GDT_ENTRY_INIT(0x0092, 0, 0),
/* 16-bit data */
[GDT_ENTRY_PNPBIOS_TS2] = GDT_ENTRY_INIT(0x0092, 0, 0),
/*
* The APM segments have byte granularity and their bases
* are set at run time. All have 64k limits.
*/
/* 32-bit code */
[GDT_ENTRY_APMBIOS_BASE] = GDT_ENTRY_INIT(0x409a, 0, 0xffff),
/* 16-bit code */
[GDT_ENTRY_APMBIOS_BASE+1] = GDT_ENTRY_INIT(0x009a, 0, 0xffff),
/* data */
[GDT_ENTRY_APMBIOS_BASE+2] = GDT_ENTRY_INIT(0x4092, 0, 0xffff),
[GDT_ENTRY_ESPFIX_SS] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
[GDT_ENTRY_PERCPU] = GDT_ENTRY_INIT(0xc092, 0, 0xfffff),
GDT_STACK_CANARY_INIT
#endif
} };
EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
static int __init x86_mpx_setup(char *s)
{
/* require an exact match without trailing characters */
if (strlen(s))
return 0;
/* do not emit a message if the feature is not present */
if (!boot_cpu_has(X86_FEATURE_MPX))
return 1;
setup_clear_cpu_cap(X86_FEATURE_MPX);
pr_info("nompx: Intel Memory Protection Extensions (MPX) disabled\n");
return 1;
}
__setup("nompx", x86_mpx_setup);
#ifdef CONFIG_X86_64
static int __init x86_nopcid_setup(char *s)
{
/* nopcid doesn't accept parameters */
if (s)
return -EINVAL;
/* do not emit a message if the feature is not present */
if (!boot_cpu_has(X86_FEATURE_PCID))
return 0;
setup_clear_cpu_cap(X86_FEATURE_PCID);
pr_info("nopcid: PCID feature disabled\n");
return 0;
}
early_param("nopcid", x86_nopcid_setup);
#endif
static int __init x86_noinvpcid_setup(char *s)
{
/* noinvpcid doesn't accept parameters */
if (s)
return -EINVAL;
/* do not emit a message if the feature is not present */
if (!boot_cpu_has(X86_FEATURE_INVPCID))
return 0;
setup_clear_cpu_cap(X86_FEATURE_INVPCID);
pr_info("noinvpcid: INVPCID feature disabled\n");
return 0;
}
early_param("noinvpcid", x86_noinvpcid_setup);
#ifdef CONFIG_X86_32
static int cachesize_override = -1;
static int disable_x86_serial_nr = 1;
static int __init cachesize_setup(char *str)
{
get_option(&str, &cachesize_override);
return 1;
}
__setup("cachesize=", cachesize_setup);
static int __init x86_sep_setup(char *s)
{
setup_clear_cpu_cap(X86_FEATURE_SEP);
return 1;
}
__setup("nosep", x86_sep_setup);
/* Standard macro to see if a specific flag is changeable */
static inline int flag_is_changeable_p(u32 flag)
{
u32 f1, f2;
/*
* Cyrix and IDT cpus allow disabling of CPUID
* so the code below may return different results
* when it is executed before and after enabling
* the CPUID. Add "volatile" to not allow gcc to
* optimize the subsequent calls to this function.
*/
asm volatile ("pushfl \n\t"
"pushfl \n\t"
"popl %0 \n\t"
"movl %0, %1 \n\t"
"xorl %2, %0 \n\t"
"pushl %0 \n\t"
"popfl \n\t"
"pushfl \n\t"
"popl %0 \n\t"
"popfl \n\t"
: "=&r" (f1), "=&r" (f2)
: "ir" (flag));
return ((f1^f2) & flag) != 0;
}
/* Probe for the CPUID instruction */
int have_cpuid_p(void)
{
return flag_is_changeable_p(X86_EFLAGS_ID);
}
static void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
{
unsigned long lo, hi;
if (!cpu_has(c, X86_FEATURE_PN) || !disable_x86_serial_nr)
return;
/* Disable processor serial number: */
rdmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
lo |= 0x200000;
wrmsr(MSR_IA32_BBL_CR_CTL, lo, hi);
pr_notice("CPU serial number disabled.\n");
clear_cpu_cap(c, X86_FEATURE_PN);
/* Disabling the serial number may affect the cpuid level */
c->cpuid_level = cpuid_eax(0);
}
static int __init x86_serial_nr_setup(char *s)
{
disable_x86_serial_nr = 0;
return 1;
}
__setup("serialnumber", x86_serial_nr_setup);
#else
static inline int flag_is_changeable_p(u32 flag)
{
return 1;
}
static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
{
}
#endif
static __init int setup_disable_smep(char *arg)
{
setup_clear_cpu_cap(X86_FEATURE_SMEP);
/* Check for things that depend on SMEP being enabled: */
check_mpx_erratum(&boot_cpu_data);
return 1;
}
__setup("nosmep", setup_disable_smep);
static __always_inline void setup_smep(struct cpuinfo_x86 *c)
{
if (cpu_has(c, X86_FEATURE_SMEP))
cr4_set_bits(X86_CR4_SMEP);
}
static __init int setup_disable_smap(char *arg)
{
setup_clear_cpu_cap(X86_FEATURE_SMAP);
return 1;
}
__setup("nosmap", setup_disable_smap);
static __always_inline void setup_smap(struct cpuinfo_x86 *c)
{
unsigned long eflags = native_save_fl();
/* This should have been cleared long ago */
BUG_ON(eflags & X86_EFLAGS_AC);
if (cpu_has(c, X86_FEATURE_SMAP)) {
#ifdef CONFIG_X86_SMAP
cr4_set_bits(X86_CR4_SMAP);
#else
cr4_clear_bits(X86_CR4_SMAP);
#endif
}
}
static __always_inline void setup_umip(struct cpuinfo_x86 *c)
{
/* Check the boot processor, plus build option for UMIP. */
if (!cpu_feature_enabled(X86_FEATURE_UMIP))
goto out;
/* Check the current processor's cpuid bits. */
if (!cpu_has(c, X86_FEATURE_UMIP))
goto out;
cr4_set_bits(X86_CR4_UMIP);
pr_info("x86/cpu: Activated the Intel User Mode Instruction Prevention (UMIP) CPU feature\n");
return;
out:
/*
* Make sure UMIP is disabled in case it was enabled in a
* previous boot (e.g., via kexec).
*/
cr4_clear_bits(X86_CR4_UMIP);
}
/*
* Protection Keys are not available in 32-bit mode.
*/
static bool pku_disabled;
static __always_inline void setup_pku(struct cpuinfo_x86 *c)
{
/* check the boot processor, plus compile options for PKU: */
if (!cpu_feature_enabled(X86_FEATURE_PKU))
return;
/* checks the actual processor's cpuid bits: */
if (!cpu_has(c, X86_FEATURE_PKU))
return;
if (pku_disabled)
return;
cr4_set_bits(X86_CR4_PKE);
/*
* Seting X86_CR4_PKE will cause the X86_FEATURE_OSPKE
* cpuid bit to be set. We need to ensure that we
* update that bit in this CPU's "cpu_info".
*/
get_cpu_cap(c);
}
#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
static __init int setup_disable_pku(char *arg)
{
/*
* Do not clear the X86_FEATURE_PKU bit. All of the
* runtime checks are against OSPKE so clearing the
* bit does nothing.
*
* This way, we will see "pku" in cpuinfo, but not
* "ospke", which is exactly what we want. It shows
* that the CPU has PKU, but the OS has not enabled it.
* This happens to be exactly how a system would look
* if we disabled the config option.
*/
pr_info("x86: 'nopku' specified, disabling Memory Protection Keys\n");
pku_disabled = true;
return 1;
}
__setup("nopku", setup_disable_pku);
#endif /* CONFIG_X86_64 */
/*
* Some CPU features depend on higher CPUID levels, which may not always
* be available due to CPUID level capping or broken virtualization
* software. Add those features to this table to auto-disable them.
*/
struct cpuid_dependent_feature {
u32 feature;
u32 level;
};
static const struct cpuid_dependent_feature
cpuid_dependent_features[] = {
{ X86_FEATURE_MWAIT, 0x00000005 },
{ X86_FEATURE_DCA, 0x00000009 },
{ X86_FEATURE_XSAVE, 0x0000000d },
{ 0, 0 }
};
static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn)
{
const struct cpuid_dependent_feature *df;
for (df = cpuid_dependent_features; df->feature; df++) {
if (!cpu_has(c, df->feature))
continue;
/*
* Note: cpuid_level is set to -1 if unavailable, but
* extended_extended_level is set to 0 if unavailable
* and the legitimate extended levels are all negative
* when signed; hence the weird messing around with
* signs here...
*/
if (!((s32)df->level < 0 ?
(u32)df->level > (u32)c->extended_cpuid_level :
(s32)df->level > (s32)c->cpuid_level))
continue;
clear_cpu_cap(c, df->feature);
if (!warn)
continue;
pr_warn("CPU: CPU feature " X86_CAP_FMT " disabled, no CPUID level 0x%x\n",
x86_cap_flag(df->feature), df->level);
}
}
/*
* Naming convention should be: <Name> [(<Codename>)]
* This table only is used unless init_<vendor>() below doesn't set it;
* in particular, if CPUID levels 0x80000002..4 are supported, this
* isn't used
*/
/* Look up CPU names by table lookup. */
static const char *table_lookup_model(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_32
const struct legacy_cpu_model_info *info;
if (c->x86_model >= 16)
return NULL; /* Range check */
if (!this_cpu)
return NULL;
info = this_cpu->legacy_models;
while (info->family) {
if (info->family == c->x86)
return info->model_names[c->x86_model];
info++;
}
#endif
return NULL; /* Not found */
}
__u32 cpu_caps_cleared[NCAPINTS + NBUGINTS];
__u32 cpu_caps_set[NCAPINTS + NBUGINTS];
void load_percpu_segment(int cpu)
{
#ifdef CONFIG_X86_32
loadsegment(fs, __KERNEL_PERCPU);
#else
__loadsegment_simple(gs, 0);
wrmsrl(MSR_GS_BASE, cpu_kernelmode_gs_base(cpu));
#endif
load_stack_canary_segment();
}
#ifdef CONFIG_X86_32
/* The 32-bit entry code needs to find cpu_entry_area. */
DEFINE_PER_CPU(struct cpu_entry_area *, cpu_entry_area);
#endif
#ifdef CONFIG_X86_64
/*
* Special IST stacks which the CPU switches to when it calls
* an IST-marked descriptor entry. Up to 7 stacks (hardware
* limit), all of them are 4K, except the debug stack which
* is 8K.
*/
static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = {
[0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
[DEBUG_STACK - 1] = DEBUG_STKSZ
};
#endif
/* Load the original GDT from the per-cpu structure */
void load_direct_gdt(int cpu)
{
struct desc_ptr gdt_descr;
gdt_descr.address = (long)get_cpu_gdt_rw(cpu);
gdt_descr.size = GDT_SIZE - 1;
load_gdt(&gdt_descr);
}
EXPORT_SYMBOL_GPL(load_direct_gdt);
/* Load a fixmap remapping of the per-cpu GDT */
void load_fixmap_gdt(int cpu)
{
struct desc_ptr gdt_descr;
gdt_descr.address = (long)get_cpu_gdt_ro(cpu);
gdt_descr.size = GDT_SIZE - 1;
load_gdt(&gdt_descr);
}
EXPORT_SYMBOL_GPL(load_fixmap_gdt);
/*
* Current gdt points %fs at the "master" per-cpu area: after this,
* it's on the real one.
*/
void switch_to_new_gdt(int cpu)
{
/* Load the original GDT */
load_direct_gdt(cpu);
/* Reload the per-cpu base */
load_percpu_segment(cpu);
}
static const struct cpu_dev *cpu_devs[X86_VENDOR_NUM] = {};
static void get_model_name(struct cpuinfo_x86 *c)
{
unsigned int *v;
char *p, *q, *s;
if (c->extended_cpuid_level < 0x80000004)
return;
v = (unsigned int *)c->x86_model_id;
cpuid(0x80000002, &v[0], &v[1], &v[2], &v[3]);
cpuid(0x80000003, &v[4], &v[5], &v[6], &v[7]);
cpuid(0x80000004, &v[8], &v[9], &v[10], &v[11]);
c->x86_model_id[48] = 0;
/* Trim whitespace */
p = q = s = &c->x86_model_id[0];
while (*p == ' ')
p++;
while (*p) {
/* Note the last non-whitespace index */
if (!isspace(*p))
s = q;
*q++ = *p++;
}
*(s + 1) = '\0';
}
void detect_num_cpu_cores(struct cpuinfo_x86 *c)
{
unsigned int eax, ebx, ecx, edx;
c->x86_max_cores = 1;
if (!IS_ENABLED(CONFIG_SMP) || c->cpuid_level < 4)
return;
cpuid_count(4, 0, &eax, &ebx, &ecx, &edx);
if (eax & 0x1f)
c->x86_max_cores = (eax >> 26) + 1;
}
void cpu_detect_cache_sizes(struct cpuinfo_x86 *c)
{
unsigned int n, dummy, ebx, ecx, edx, l2size;
n = c->extended_cpuid_level;
if (n >= 0x80000005) {
cpuid(0x80000005, &dummy, &ebx, &ecx, &edx);
c->x86_cache_size = (ecx>>24) + (edx>>24);
#ifdef CONFIG_X86_64
/* On K8 L1 TLB is inclusive, so don't count it */
c->x86_tlbsize = 0;
#endif
}
if (n < 0x80000006) /* Some chips just has a large L1. */
return;
cpuid(0x80000006, &dummy, &ebx, &ecx, &edx);
l2size = ecx >> 16;
#ifdef CONFIG_X86_64
c->x86_tlbsize += ((ebx >> 16) & 0xfff) + (ebx & 0xfff);
#else
/* do processor-specific cache resizing */
if (this_cpu->legacy_cache_size)
l2size = this_cpu->legacy_cache_size(c, l2size);
/* Allow user to override all this if necessary. */
if (cachesize_override != -1)
l2size = cachesize_override;
if (l2size == 0)
return; /* Again, no L2 cache is possible */
#endif
c->x86_cache_size = l2size;
}
u16 __read_mostly tlb_lli_4k[NR_INFO];
u16 __read_mostly tlb_lli_2m[NR_INFO];
u16 __read_mostly tlb_lli_4m[NR_INFO];
u16 __read_mostly tlb_lld_4k[NR_INFO];
u16 __read_mostly tlb_lld_2m[NR_INFO];
u16 __read_mostly tlb_lld_4m[NR_INFO];
u16 __read_mostly tlb_lld_1g[NR_INFO];
static void cpu_detect_tlb(struct cpuinfo_x86 *c)
{
if (this_cpu->c_detect_tlb)
this_cpu->c_detect_tlb(c);
pr_info("Last level iTLB entries: 4KB %d, 2MB %d, 4MB %d\n",
tlb_lli_4k[ENTRIES], tlb_lli_2m[ENTRIES],
tlb_lli_4m[ENTRIES]);
pr_info("Last level dTLB entries: 4KB %d, 2MB %d, 4MB %d, 1GB %d\n",
tlb_lld_4k[ENTRIES], tlb_lld_2m[ENTRIES],
tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]);
}
void detect_ht(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_SMP
u32 eax, ebx, ecx, edx;
int index_msb, core_bits;
static bool printed;
if (!cpu_has(c, X86_FEATURE_HT))
return;
if (cpu_has(c, X86_FEATURE_CMP_LEGACY))
goto out;
if (cpu_has(c, X86_FEATURE_XTOPOLOGY))
return;
cpuid(1, &eax, &ebx, &ecx, &edx);
smp_num_siblings = (ebx & 0xff0000) >> 16;
if (smp_num_siblings == 1) {
pr_info_once("CPU0: Hyper-Threading is disabled\n");
goto out;
}
if (smp_num_siblings <= 1)
goto out;
index_msb = get_count_order(smp_num_siblings);
c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb);
smp_num_siblings = smp_num_siblings / c->x86_max_cores;
index_msb = get_count_order(smp_num_siblings);
core_bits = get_count_order(c->x86_max_cores);
c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, index_msb) &
((1 << core_bits) - 1);
out:
if (!printed && (c->x86_max_cores * smp_num_siblings) > 1) {
pr_info("CPU: Physical Processor ID: %d\n",
c->phys_proc_id);
pr_info("CPU: Processor Core ID: %d\n",
c->cpu_core_id);
printed = 1;
}
#endif
}
static void get_cpu_vendor(struct cpuinfo_x86 *c)
{
char *v = c->x86_vendor_id;
int i;
for (i = 0; i < X86_VENDOR_NUM; i++) {
if (!cpu_devs[i])
break;
if (!strcmp(v, cpu_devs[i]->c_ident[0]) ||
(cpu_devs[i]->c_ident[1] &&
!strcmp(v, cpu_devs[i]->c_ident[1]))) {
this_cpu = cpu_devs[i];
c->x86_vendor = this_cpu->c_x86_vendor;
return;
}
}
pr_err_once("CPU: vendor_id '%s' unknown, using generic init.\n" \
"CPU: Your system may be unstable.\n", v);
c->x86_vendor = X86_VENDOR_UNKNOWN;
this_cpu = &default_cpu;
}
void cpu_detect(struct cpuinfo_x86 *c)
{
/* Get vendor name */
cpuid(0x00000000, (unsigned int *)&c->cpuid_level,
(unsigned int *)&c->x86_vendor_id[0],
(unsigned int *)&c->x86_vendor_id[8],
(unsigned int *)&c->x86_vendor_id[4]);
c->x86 = 4;
/* Intel-defined flags: level 0x00000001 */
if (c->cpuid_level >= 0x00000001) {
u32 junk, tfms, cap0, misc;
cpuid(0x00000001, &tfms, &misc, &junk, &cap0);
c->x86 = x86_family(tfms);
c->x86_model = x86_model(tfms);
c->x86_stepping = x86_stepping(tfms);
if (cap0 & (1<<19)) {
c->x86_clflush_size = ((misc >> 8) & 0xff) * 8;
c->x86_cache_alignment = c->x86_clflush_size;
}
}
}
static void apply_forced_caps(struct cpuinfo_x86 *c)
{
int i;
for (i = 0; i < NCAPINTS + NBUGINTS; i++) {
c->x86_capability[i] &= ~cpu_caps_cleared[i];
c->x86_capability[i] |= cpu_caps_set[i];
}
}
static void init_speculation_control(struct cpuinfo_x86 *c)
{
/*
* The Intel SPEC_CTRL CPUID bit implies IBRS and IBPB support,
* and they also have a different bit for STIBP support. Also,
* a hypervisor might have set the individual AMD bits even on
* Intel CPUs, for finer-grained selection of what's available.
*/
if (cpu_has(c, X86_FEATURE_SPEC_CTRL)) {
set_cpu_cap(c, X86_FEATURE_IBRS);
set_cpu_cap(c, X86_FEATURE_IBPB);
set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL);
}
if (cpu_has(c, X86_FEATURE_INTEL_STIBP))
set_cpu_cap(c, X86_FEATURE_STIBP);
if (cpu_has(c, X86_FEATURE_SPEC_CTRL_SSBD) ||
cpu_has(c, X86_FEATURE_VIRT_SSBD))
set_cpu_cap(c, X86_FEATURE_SSBD);
if (cpu_has(c, X86_FEATURE_AMD_IBRS)) {
set_cpu_cap(c, X86_FEATURE_IBRS);
set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL);
}
if (cpu_has(c, X86_FEATURE_AMD_IBPB))
set_cpu_cap(c, X86_FEATURE_IBPB);
if (cpu_has(c, X86_FEATURE_AMD_STIBP)) {
set_cpu_cap(c, X86_FEATURE_STIBP);
set_cpu_cap(c, X86_FEATURE_MSR_SPEC_CTRL);
}
}
void get_cpu_cap(struct cpuinfo_x86 *c)
{
u32 eax, ebx, ecx, edx;
/* Intel-defined flags: level 0x00000001 */
if (c->cpuid_level >= 0x00000001) {
cpuid(0x00000001, &eax, &ebx, &ecx, &edx);
c->x86_capability[CPUID_1_ECX] = ecx;
c->x86_capability[CPUID_1_EDX] = edx;
}
/* Thermal and Power Management Leaf: level 0x00000006 (eax) */
if (c->cpuid_level >= 0x00000006)
c->x86_capability[CPUID_6_EAX] = cpuid_eax(0x00000006);
/* Additional Intel-defined flags: level 0x00000007 */
if (c->cpuid_level >= 0x00000007) {
cpuid_count(0x00000007, 0, &eax, &ebx, &ecx, &edx);
c->x86_capability[CPUID_7_0_EBX] = ebx;
c->x86_capability[CPUID_7_ECX] = ecx;
c->x86_capability[CPUID_7_EDX] = edx;
}
/* Extended state features: level 0x0000000d */
if (c->cpuid_level >= 0x0000000d) {
cpuid_count(0x0000000d, 1, &eax, &ebx, &ecx, &edx);
c->x86_capability[CPUID_D_1_EAX] = eax;
}
/* Additional Intel-defined flags: level 0x0000000F */
if (c->cpuid_level >= 0x0000000F) {
/* QoS sub-leaf, EAX=0Fh, ECX=0 */
cpuid_count(0x0000000F, 0, &eax, &ebx, &ecx, &edx);
c->x86_capability[CPUID_F_0_EDX] = edx;
if (cpu_has(c, X86_FEATURE_CQM_LLC)) {
/* will be overridden if occupancy monitoring exists */
c->x86_cache_max_rmid = ebx;
/* QoS sub-leaf, EAX=0Fh, ECX=1 */
cpuid_count(0x0000000F, 1, &eax, &ebx, &ecx, &edx);
c->x86_capability[CPUID_F_1_EDX] = edx;
if ((cpu_has(c, X86_FEATURE_CQM_OCCUP_LLC)) ||
((cpu_has(c, X86_FEATURE_CQM_MBM_TOTAL)) ||
(cpu_has(c, X86_FEATURE_CQM_MBM_LOCAL)))) {
c->x86_cache_max_rmid = ecx;
c->x86_cache_occ_scale = ebx;
}
} else {
c->x86_cache_max_rmid = -1;
c->x86_cache_occ_scale = -1;
}
}
/* AMD-defined flags: level 0x80000001 */
eax = cpuid_eax(0x80000000);
c->extended_cpuid_level = eax;
if ((eax & 0xffff0000) == 0x80000000) {
if (eax >= 0x80000001) {
cpuid(0x80000001, &eax, &ebx, &ecx, &edx);
c->x86_capability[CPUID_8000_0001_ECX] = ecx;
c->x86_capability[CPUID_8000_0001_EDX] = edx;
}
}
if (c->extended_cpuid_level >= 0x80000007) {
cpuid(0x80000007, &eax, &ebx, &ecx, &edx);
c->x86_capability[CPUID_8000_0007_EBX] = ebx;
c->x86_power = edx;
}
if (c->extended_cpuid_level >= 0x80000008) {
cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
c->x86_capability[CPUID_8000_0008_EBX] = ebx;
}
if (c->extended_cpuid_level >= 0x8000000a)
c->x86_capability[CPUID_8000_000A_EDX] = cpuid_edx(0x8000000a);
init_scattered_cpuid_features(c);
init_speculation_control(c);
/*
* Clear/Set all flags overridden by options, after probe.
* This needs to happen each time we re-probe, which may happen
* several times during CPU initialization.
*/
apply_forced_caps(c);
}
static void get_cpu_address_sizes(struct cpuinfo_x86 *c)
{
u32 eax, ebx, ecx, edx;
if (c->extended_cpuid_level >= 0x80000008) {
cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
c->x86_virt_bits = (eax >> 8) & 0xff;
c->x86_phys_bits = eax & 0xff;
}
#ifdef CONFIG_X86_32
else if (cpu_has(c, X86_FEATURE_PAE) || cpu_has(c, X86_FEATURE_PSE36))
c->x86_phys_bits = 36;
#endif
}
static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_32
int i;
/*
* First of all, decide if this is a 486 or higher
* It's a 486 if we can modify the AC flag
*/
if (flag_is_changeable_p(X86_EFLAGS_AC))
c->x86 = 4;
else
c->x86 = 3;
for (i = 0; i < X86_VENDOR_NUM; i++)
if (cpu_devs[i] && cpu_devs[i]->c_identify) {
c->x86_vendor_id[0] = 0;
cpu_devs[i]->c_identify(c);
if (c->x86_vendor_id[0]) {
get_cpu_vendor(c);
break;
}
}
#endif
}
static const __initconst struct x86_cpu_id cpu_no_speculation[] = {
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CEDARVIEW, X86_FEATURE_ANY },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_CLOVERVIEW, X86_FEATURE_ANY },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_LINCROFT, X86_FEATURE_ANY },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PENWELL, X86_FEATURE_ANY },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_PINEVIEW, X86_FEATURE_ANY },
{ X86_VENDOR_CENTAUR, 5 },
{ X86_VENDOR_INTEL, 5 },
{ X86_VENDOR_NSC, 5 },
{ X86_VENDOR_ANY, 4 },
{}
};
static const __initconst struct x86_cpu_id cpu_no_meltdown[] = {
{ X86_VENDOR_AMD },
{}
};
/* Only list CPUs which speculate but are non susceptible to SSB */
static const __initconst struct x86_cpu_id cpu_no_spec_store_bypass[] = {
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT1 },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT2 },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_MERRIFIELD },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_CORE_YONAH },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNL },
{ X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNM },
{ X86_VENDOR_AMD, 0x12, },
{ X86_VENDOR_AMD, 0x11, },
{ X86_VENDOR_AMD, 0x10, },
{ X86_VENDOR_AMD, 0xf, },
{}
};
static void __init cpu_set_bug_bits(struct cpuinfo_x86 *c)
{
u64 ia32_cap = 0;
if (x86_match_cpu(cpu_no_speculation))
return;
setup_force_cpu_bug(X86_BUG_SPECTRE_V1);
setup_force_cpu_bug(X86_BUG_SPECTRE_V2);
if (cpu_has(c, X86_FEATURE_ARCH_CAPABILITIES))
rdmsrl(MSR_IA32_ARCH_CAPABILITIES, ia32_cap);
if (!x86_match_cpu(cpu_no_spec_store_bypass) &&
!(ia32_cap & ARCH_CAP_SSB_NO))
setup_force_cpu_bug(X86_BUG_SPEC_STORE_BYPASS);
if (x86_match_cpu(cpu_no_meltdown))
return;
/* Rogue Data Cache Load? No! */
if (ia32_cap & ARCH_CAP_RDCL_NO)
return;
setup_force_cpu_bug(X86_BUG_CPU_MELTDOWN);
}
/*
* Do minimum CPU detection early.
* Fields really needed: vendor, cpuid_level, family, model, mask,
* cache alignment.
* The others are not touched to avoid unwanted side effects.
*
* WARNING: this function is only called on the boot CPU. Don't add code
* here that is supposed to run on all CPUs.
*/
static void __init early_identify_cpu(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_64
c->x86_clflush_size = 64;
c->x86_phys_bits = 36;
c->x86_virt_bits = 48;
#else
c->x86_clflush_size = 32;
c->x86_phys_bits = 32;
c->x86_virt_bits = 32;
#endif
c->x86_cache_alignment = c->x86_clflush_size;
memset(&c->x86_capability, 0, sizeof c->x86_capability);
c->extended_cpuid_level = 0;
/* cyrix could have cpuid enabled via c_identify()*/
if (have_cpuid_p()) {
cpu_detect(c);
get_cpu_vendor(c);
get_cpu_cap(c);
get_cpu_address_sizes(c);
setup_force_cpu_cap(X86_FEATURE_CPUID);
if (this_cpu->c_early_init)
this_cpu->c_early_init(c);
c->cpu_index = 0;
filter_cpuid_features(c, false);
if (this_cpu->c_bsp_init)
this_cpu->c_bsp_init(c);
} else {
identify_cpu_without_cpuid(c);
setup_clear_cpu_cap(X86_FEATURE_CPUID);
}
setup_force_cpu_cap(X86_FEATURE_ALWAYS);
cpu_set_bug_bits(c);
fpu__init_system(c);
#ifdef CONFIG_X86_32
/*
* Regardless of whether PCID is enumerated, the SDM says
* that it can't be enabled in 32-bit mode.
*/
setup_clear_cpu_cap(X86_FEATURE_PCID);
#endif
/*
* Later in the boot process pgtable_l5_enabled() relies on
* cpu_feature_enabled(X86_FEATURE_LA57). If 5-level paging is not
* enabled by this point we need to clear the feature bit to avoid
* false-positives at the later stage.
*
* pgtable_l5_enabled() can be false here for several reasons:
* - 5-level paging is disabled compile-time;
* - it's 32-bit kernel;
* - machine doesn't support 5-level paging;
* - user specified 'no5lvl' in kernel command line.
*/
if (!pgtable_l5_enabled())
setup_clear_cpu_cap(X86_FEATURE_LA57);
}
void __init early_cpu_init(void)
{
const struct cpu_dev *const *cdev;
int count = 0;
#ifdef CONFIG_PROCESSOR_SELECT
pr_info("KERNEL supported cpus:\n");
#endif
for (cdev = __x86_cpu_dev_start; cdev < __x86_cpu_dev_end; cdev++) {
const struct cpu_dev *cpudev = *cdev;
if (count >= X86_VENDOR_NUM)
break;
cpu_devs[count] = cpudev;
count++;
#ifdef CONFIG_PROCESSOR_SELECT
{
unsigned int j;
for (j = 0; j < 2; j++) {
if (!cpudev->c_ident[j])
continue;
pr_info(" %s %s\n", cpudev->c_vendor,
cpudev->c_ident[j]);
}
}
#endif
}
early_identify_cpu(&boot_cpu_data);
}
/*
* The NOPL instruction is supposed to exist on all CPUs of family >= 6;
* unfortunately, that's not true in practice because of early VIA
* chips and (more importantly) broken virtualizers that are not easy
* to detect. In the latter case it doesn't even *fail* reliably, so
* probing for it doesn't even work. Disable it completely on 32-bit
* unless we can find a reliable way to detect all the broken cases.
* Enable it explicitly on 64-bit for non-constant inputs of cpu_has().
*/
static void detect_nopl(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_32
clear_cpu_cap(c, X86_FEATURE_NOPL);
#else
set_cpu_cap(c, X86_FEATURE_NOPL);
#endif
}
static void detect_null_seg_behavior(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_64
/*
* Empirically, writing zero to a segment selector on AMD does
* not clear the base, whereas writing zero to a segment
* selector on Intel does clear the base. Intel's behavior
* allows slightly faster context switches in the common case
* where GS is unused by the prev and next threads.
*
* Since neither vendor documents this anywhere that I can see,
* detect it directly instead of hardcoding the choice by
* vendor.
*
* I've designated AMD's behavior as the "bug" because it's
* counterintuitive and less friendly.
*/
unsigned long old_base, tmp;
rdmsrl(MSR_FS_BASE, old_base);
wrmsrl(MSR_FS_BASE, 1);
loadsegment(fs, 0);
rdmsrl(MSR_FS_BASE, tmp);
if (tmp != 0)
set_cpu_bug(c, X86_BUG_NULL_SEG);
wrmsrl(MSR_FS_BASE, old_base);
#endif
}
static void generic_identify(struct cpuinfo_x86 *c)
{
c->extended_cpuid_level = 0;
if (!have_cpuid_p())
identify_cpu_without_cpuid(c);
/* cyrix could have cpuid enabled via c_identify()*/
if (!have_cpuid_p())
return;
cpu_detect(c);
get_cpu_vendor(c);
get_cpu_cap(c);
get_cpu_address_sizes(c);
if (c->cpuid_level >= 0x00000001) {
c->initial_apicid = (cpuid_ebx(1) >> 24) & 0xFF;
#ifdef CONFIG_X86_32
# ifdef CONFIG_SMP
c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
# else
c->apicid = c->initial_apicid;
# endif
#endif
c->phys_proc_id = c->initial_apicid;
}
get_model_name(c); /* Default name */
detect_nopl(c);
detect_null_seg_behavior(c);
/*
* ESPFIX is a strange bug. All real CPUs have it. Paravirt
* systems that run Linux at CPL > 0 may or may not have the
* issue, but, even if they have the issue, there's absolutely
* nothing we can do about it because we can't use the real IRET
* instruction.
*
* NB: For the time being, only 32-bit kernels support
* X86_BUG_ESPFIX as such. 64-bit kernels directly choose
* whether to apply espfix using paravirt hooks. If any
* non-paravirt system ever shows up that does *not* have the
* ESPFIX issue, we can change this.
*/
#ifdef CONFIG_X86_32
# ifdef CONFIG_PARAVIRT
do {
extern void native_iret(void);
if (pv_cpu_ops.iret == native_iret)
set_cpu_bug(c, X86_BUG_ESPFIX);
} while (0);
# else
set_cpu_bug(c, X86_BUG_ESPFIX);
# endif
#endif
}
static void x86_init_cache_qos(struct cpuinfo_x86 *c)
{
/*
* The heavy lifting of max_rmid and cache_occ_scale are handled
* in get_cpu_cap(). Here we just set the max_rmid for the boot_cpu
* in case CQM bits really aren't there in this CPU.
*/
if (c != &boot_cpu_data) {
boot_cpu_data.x86_cache_max_rmid =
min(boot_cpu_data.x86_cache_max_rmid,
c->x86_cache_max_rmid);
}
}
/*
* Validate that ACPI/mptables have the same information about the
* effective APIC id and update the package map.
*/
static void validate_apic_and_package_id(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_SMP
unsigned int apicid, cpu = smp_processor_id();
apicid = apic->cpu_present_to_apicid(cpu);
if (apicid != c->apicid) {
pr_err(FW_BUG "CPU%u: APIC id mismatch. Firmware: %x APIC: %x\n",
cpu, apicid, c->initial_apicid);
}
BUG_ON(topology_update_package_map(c->phys_proc_id, cpu));
#else
c->logical_proc_id = 0;
#endif
}
/*
* This does the hard work of actually picking apart the CPU stuff...
*/
static void identify_cpu(struct cpuinfo_x86 *c)
{
int i;
c->loops_per_jiffy = loops_per_jiffy;
c->x86_cache_size = 0;
c->x86_vendor = X86_VENDOR_UNKNOWN;
c->x86_model = c->x86_stepping = 0; /* So far unknown... */
c->x86_vendor_id[0] = '\0'; /* Unset */
c->x86_model_id[0] = '\0'; /* Unset */
c->x86_max_cores = 1;
c->x86_coreid_bits = 0;
c->cu_id = 0xff;
#ifdef CONFIG_X86_64
c->x86_clflush_size = 64;
c->x86_phys_bits = 36;
c->x86_virt_bits = 48;
#else
c->cpuid_level = -1; /* CPUID not detected */
c->x86_clflush_size = 32;
c->x86_phys_bits = 32;
c->x86_virt_bits = 32;
#endif
c->x86_cache_alignment = c->x86_clflush_size;
memset(&c->x86_capability, 0, sizeof c->x86_capability);
generic_identify(c);
if (this_cpu->c_identify)
this_cpu->c_identify(c);
/* Clear/Set all flags overridden by options, after probe */
apply_forced_caps(c);
#ifdef CONFIG_X86_64
c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
#endif
/*
* Vendor-specific initialization. In this section we
* canonicalize the feature flags, meaning if there are
* features a certain CPU supports which CPUID doesn't
* tell us, CPUID claiming incorrect flags, or other bugs,
* we handle them here.
*
* At the end of this section, c->x86_capability better
* indicate the features this CPU genuinely supports!
*/
if (this_cpu->c_init)
this_cpu->c_init(c);
/* Disable the PN if appropriate */
squash_the_stupid_serial_number(c);
/* Set up SMEP/SMAP/UMIP */
setup_smep(c);
setup_smap(c);
setup_umip(c);
/*
* The vendor-specific functions might have changed features.
* Now we do "generic changes."
*/
/* Filter out anything that depends on CPUID levels we don't have */
filter_cpuid_features(c, true);
/* If the model name is still unset, do table lookup. */
if (!c->x86_model_id[0]) {
const char *p;
p = table_lookup_model(c);
if (p)
strcpy(c->x86_model_id, p);
else
/* Last resort... */
sprintf(c->x86_model_id, "%02x/%02x",
c->x86, c->x86_model);
}
#ifdef CONFIG_X86_64
detect_ht(c);
#endif
x86_init_rdrand(c);
x86_init_cache_qos(c);
setup_pku(c);
/*
* Clear/Set all flags overridden by options, need do it
* before following smp all cpus cap AND.
*/
apply_forced_caps(c);
/*
* On SMP, boot_cpu_data holds the common feature set between
* all CPUs; so make sure that we indicate which features are
* common between the CPUs. The first time this routine gets
* executed, c == &boot_cpu_data.
*/
if (c != &boot_cpu_data) {
/* AND the already accumulated flags with these */
for (i = 0; i < NCAPINTS; i++)
boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
/* OR, i.e. replicate the bug flags */
for (i = NCAPINTS; i < NCAPINTS + NBUGINTS; i++)
c->x86_capability[i] |= boot_cpu_data.x86_capability[i];
}
/* Init Machine Check Exception if available. */
mcheck_cpu_init(c);
select_idle_routine(c);
#ifdef CONFIG_NUMA
numa_add_cpu(smp_processor_id());
#endif
}
/*
* Set up the CPU state needed to execute SYSENTER/SYSEXIT instructions
* on 32-bit kernels:
*/
#ifdef CONFIG_X86_32
void enable_sep_cpu(void)
{
struct tss_struct *tss;
int cpu;
if (!boot_cpu_has(X86_FEATURE_SEP))
return;
cpu = get_cpu();
tss = &per_cpu(cpu_tss_rw, cpu);
/*
* We cache MSR_IA32_SYSENTER_CS's value in the TSS's ss1 field --
* see the big comment in struct x86_hw_tss's definition.
*/
tss->x86_tss.ss1 = __KERNEL_CS;
wrmsr(MSR_IA32_SYSENTER_CS, tss->x86_tss.ss1, 0);
wrmsr(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1), 0);
wrmsr(MSR_IA32_SYSENTER_EIP, (unsigned long)entry_SYSENTER_32, 0);
put_cpu();
}
#endif
void __init identify_boot_cpu(void)
{
identify_cpu(&boot_cpu_data);
#ifdef CONFIG_X86_32
sysenter_setup();
enable_sep_cpu();
#endif
cpu_detect_tlb(&boot_cpu_data);
}
void identify_secondary_cpu(struct cpuinfo_x86 *c)
{
BUG_ON(c == &boot_cpu_data);
identify_cpu(c);
#ifdef CONFIG_X86_32
enable_sep_cpu();
#endif
mtrr_ap_init();
validate_apic_and_package_id(c);
x86_spec_ctrl_setup_ap();
}
static __init int setup_noclflush(char *arg)
{
setup_clear_cpu_cap(X86_FEATURE_CLFLUSH);
setup_clear_cpu_cap(X86_FEATURE_CLFLUSHOPT);
return 1;
}
__setup("noclflush", setup_noclflush);
void print_cpu_info(struct cpuinfo_x86 *c)
{
const char *vendor = NULL;
if (c->x86_vendor < X86_VENDOR_NUM) {
vendor = this_cpu->c_vendor;
} else {
if (c->cpuid_level >= 0)
vendor = c->x86_vendor_id;
}
if (vendor && !strstr(c->x86_model_id, vendor))
pr_cont("%s ", vendor);
if (c->x86_model_id[0])
pr_cont("%s", c->x86_model_id);
else
pr_cont("%d86", c->x86);
pr_cont(" (family: 0x%x, model: 0x%x", c->x86, c->x86_model);
if (c->x86_stepping || c->cpuid_level >= 0)
pr_cont(", stepping: 0x%x)\n", c->x86_stepping);
else
pr_cont(")\n");
}
/*
* clearcpuid= was already parsed in fpu__init_parse_early_param.
* But we need to keep a dummy __setup around otherwise it would
* show up as an environment variable for init.
*/
static __init int setup_clearcpuid(char *arg)
{
return 1;
}
__setup("clearcpuid=", setup_clearcpuid);
#ifdef CONFIG_X86_64
DEFINE_PER_CPU_FIRST(union irq_stack_union,
irq_stack_union) __aligned(PAGE_SIZE) __visible;
EXPORT_PER_CPU_SYMBOL_GPL(irq_stack_union);
/*
* The following percpu variables are hot. Align current_task to
* cacheline size such that they fall in the same cacheline.
*/
DEFINE_PER_CPU(struct task_struct *, current_task) ____cacheline_aligned =
&init_task;
EXPORT_PER_CPU_SYMBOL(current_task);
DEFINE_PER_CPU(char *, irq_stack_ptr) =
init_per_cpu_var(irq_stack_union.irq_stack) + IRQ_STACK_SIZE;
DEFINE_PER_CPU(unsigned int, irq_count) __visible = -1;
DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT;
EXPORT_PER_CPU_SYMBOL(__preempt_count);
/* May not be marked __init: used by software suspend */
void syscall_init(void)
{
extern char _entry_trampoline[];
extern char entry_SYSCALL_64_trampoline[];
int cpu = smp_processor_id();
unsigned long SYSCALL64_entry_trampoline =
(unsigned long)get_cpu_entry_area(cpu)->entry_trampoline +
(entry_SYSCALL_64_trampoline - _entry_trampoline);
wrmsr(MSR_STAR, 0, (__USER32_CS << 16) | __KERNEL_CS);
if (static_cpu_has(X86_FEATURE_PTI))
wrmsrl(MSR_LSTAR, SYSCALL64_entry_trampoline);
else
wrmsrl(MSR_LSTAR, (unsigned long)entry_SYSCALL_64);
#ifdef CONFIG_IA32_EMULATION
wrmsrl(MSR_CSTAR, (unsigned long)entry_SYSCALL_compat);
/*
* This only works on Intel CPUs.
* On AMD CPUs these MSRs are 32-bit, CPU truncates MSR_IA32_SYSENTER_EIP.
* This does not cause SYSENTER to jump to the wrong location, because
* AMD doesn't allow SYSENTER in long mode (either 32- or 64-bit).
*/
wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
wrmsrl_safe(MSR_IA32_SYSENTER_ESP, (unsigned long)(cpu_entry_stack(cpu) + 1));
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)entry_SYSENTER_compat);
#else
wrmsrl(MSR_CSTAR, (unsigned long)ignore_sysret);
wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG);
wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL);
wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL);
#endif
/* Flags to clear on syscall */
wrmsrl(MSR_SYSCALL_MASK,
X86_EFLAGS_TF|X86_EFLAGS_DF|X86_EFLAGS_IF|
X86_EFLAGS_IOPL|X86_EFLAGS_AC|X86_EFLAGS_NT);
}
/*
* Copies of the original ist values from the tss are only accessed during
* debugging, no special alignment required.
*/
DEFINE_PER_CPU(struct orig_ist, orig_ist);
static DEFINE_PER_CPU(unsigned long, debug_stack_addr);
DEFINE_PER_CPU(int, debug_stack_usage);
int is_debug_stack(unsigned long addr)
{
return __this_cpu_read(debug_stack_usage) ||
(addr <= __this_cpu_read(debug_stack_addr) &&
addr > (__this_cpu_read(debug_stack_addr) - DEBUG_STKSZ));
}
NOKPROBE_SYMBOL(is_debug_stack);
DEFINE_PER_CPU(u32, debug_idt_ctr);
void debug_stack_set_zero(void)
{
this_cpu_inc(debug_idt_ctr);
load_current_idt();
}
NOKPROBE_SYMBOL(debug_stack_set_zero);
void debug_stack_reset(void)
{
if (WARN_ON(!this_cpu_read(debug_idt_ctr)))
return;
if (this_cpu_dec_return(debug_idt_ctr) == 0)
load_current_idt();
}
NOKPROBE_SYMBOL(debug_stack_reset);
#else /* CONFIG_X86_64 */
DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
EXPORT_PER_CPU_SYMBOL(current_task);
DEFINE_PER_CPU(int, __preempt_count) = INIT_PREEMPT_COUNT;
EXPORT_PER_CPU_SYMBOL(__preempt_count);
/*
* On x86_32, vm86 modifies tss.sp0, so sp0 isn't a reliable way to find
* the top of the kernel stack. Use an extra percpu variable to track the
* top of the kernel stack directly.
*/
DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) =
(unsigned long)&init_thread_union + THREAD_SIZE;
EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack);
#ifdef CONFIG_CC_STACKPROTECTOR
DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary);
#endif
#endif /* CONFIG_X86_64 */
/*
* Clear all 6 debug registers:
*/
static void clear_all_debug_regs(void)
{
int i;
for (i = 0; i < 8; i++) {
/* Ignore db4, db5 */
if ((i == 4) || (i == 5))
continue;
set_debugreg(0, i);
}
}
#ifdef CONFIG_KGDB
/*
* Restore debug regs if using kgdbwait and you have a kernel debugger
* connection established.
*/
static void dbg_restore_debug_regs(void)
{
if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break))
arch_kgdb_ops.correct_hw_break();
}
#else /* ! CONFIG_KGDB */
#define dbg_restore_debug_regs()
#endif /* ! CONFIG_KGDB */
static void wait_for_master_cpu(int cpu)
{
#ifdef CONFIG_SMP
/*
* wait for ACK from master CPU before continuing
* with AP initialization
*/
WARN_ON(cpumask_test_and_set_cpu(cpu, cpu_initialized_mask));
while (!cpumask_test_cpu(cpu, cpu_callout_mask))
cpu_relax();
#endif
}
/*
* cpu_init() initializes state that is per-CPU. Some data is already
* initialized (naturally) in the bootstrap process, such as the GDT
* and IDT. We reload them nevertheless, this function acts as a
* 'CPU state barrier', nothing should get across.
* A lot of state is already set up in PDA init for 64 bit
*/
#ifdef CONFIG_X86_64
void cpu_init(void)
{
struct orig_ist *oist;
struct task_struct *me;
struct tss_struct *t;
unsigned long v;
int cpu = raw_smp_processor_id();
int i;
wait_for_master_cpu(cpu);
/*
* Initialize the CR4 shadow before doing anything that could
* try to read it.
*/
cr4_init_shadow();
if (cpu)
load_ucode_ap();
t = &per_cpu(cpu_tss_rw, cpu);
oist = &per_cpu(orig_ist, cpu);
#ifdef CONFIG_NUMA
if (this_cpu_read(numa_node) == 0 &&
early_cpu_to_node(cpu) != NUMA_NO_NODE)
set_numa_node(early_cpu_to_node(cpu));
#endif
me = current;
pr_debug("Initializing CPU#%d\n", cpu);
cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
/*
* Initialize the per-CPU GDT with the boot GDT,
* and set up the GDT descriptor:
*/
switch_to_new_gdt(cpu);
loadsegment(fs, 0);
load_current_idt();
memset(me->thread.tls_array, 0, GDT_ENTRY_TLS_ENTRIES * 8);
syscall_init();
wrmsrl(MSR_FS_BASE, 0);
wrmsrl(MSR_KERNEL_GS_BASE, 0);
barrier();
x86_configure_nx();
x2apic_setup();
/*
* set up and load the per-CPU TSS
*/
if (!oist->ist[0]) {
char *estacks = get_cpu_entry_area(cpu)->exception_stacks;
for (v = 0; v < N_EXCEPTION_STACKS; v++) {
estacks += exception_stack_sizes[v];
oist->ist[v] = t->x86_tss.ist[v] =
(unsigned long)estacks;
if (v == DEBUG_STACK-1)
per_cpu(debug_stack_addr, cpu) = (unsigned long)estacks;
}
}
t->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
/*
* <= is required because the CPU will access up to
* 8 bits beyond the end of the IO permission bitmap.
*/
for (i = 0; i <= IO_BITMAP_LONGS; i++)
t->io_bitmap[i] = ~0UL;
mmgrab(&init_mm);
me->active_mm = &init_mm;
BUG_ON(me->mm);
initialize_tlbstate_and_flush();
enter_lazy_tlb(&init_mm, me);
/*
* Initialize the TSS. sp0 points to the entry trampoline stack
* regardless of what task is running.
*/
set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
load_TR_desc();
load_sp0((unsigned long)(cpu_entry_stack(cpu) + 1));
load_mm_ldt(&init_mm);
clear_all_debug_regs();
dbg_restore_debug_regs();
fpu__init_cpu();
if (is_uv_system())
uv_cpu_init();
load_fixmap_gdt(cpu);
}
#else
void cpu_init(void)
{
int cpu = smp_processor_id();
struct task_struct *curr = current;
struct tss_struct *t = &per_cpu(cpu_tss_rw, cpu);
wait_for_master_cpu(cpu);
/*
* Initialize the CR4 shadow before doing anything that could
* try to read it.
*/
cr4_init_shadow();
show_ucode_info_early();
pr_info("Initializing CPU#%d\n", cpu);
if (cpu_feature_enabled(X86_FEATURE_VME) ||
boot_cpu_has(X86_FEATURE_TSC) ||
boot_cpu_has(X86_FEATURE_DE))
cr4_clear_bits(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
load_current_idt();
switch_to_new_gdt(cpu);
/*
* Set up and load the per-CPU TSS and LDT
*/
mmgrab(&init_mm);
curr->active_mm = &init_mm;
BUG_ON(curr->mm);
initialize_tlbstate_and_flush();
enter_lazy_tlb(&init_mm, curr);
/*
* Initialize the TSS. Don't bother initializing sp0, as the initial
* task never enters user mode.
*/
set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
load_TR_desc();
load_mm_ldt(&init_mm);
t->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET;
#ifdef CONFIG_DOUBLEFAULT
/* Set up doublefault TSS pointer in the GDT */
__set_tss_desc(cpu, GDT_ENTRY_DOUBLEFAULT_TSS, &doublefault_tss);
#endif
clear_all_debug_regs();
dbg_restore_debug_regs();
fpu__init_cpu();
load_fixmap_gdt(cpu);
}
#endif
static void bsp_resume(void)
{
if (this_cpu->c_bsp_resume)
this_cpu->c_bsp_resume(&boot_cpu_data);
}
static struct syscore_ops cpu_syscore_ops = {
.resume = bsp_resume,
};
static int __init init_cpu_syscore(void)
{
register_syscore_ops(&cpu_syscore_ops);
return 0;
}
core_initcall(init_cpu_syscore);
/*
* The microcode loader calls this upon late microcode load to recheck features,
* only when microcode has been updated. Caller holds microcode_mutex and CPU
* hotplug lock.
*/
void microcode_check(void)
{
struct cpuinfo_x86 info;
perf_check_microcode();
/* Reload CPUID max function as it might've changed. */
info.cpuid_level = cpuid_eax(0);
/*
* Copy all capability leafs to pick up the synthetic ones so that
* memcmp() below doesn't fail on that. The ones coming from CPUID will
* get overwritten in get_cpu_cap().
*/
memcpy(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability));
get_cpu_cap(&info);
if (!memcmp(&info.x86_capability, &boot_cpu_data.x86_capability, sizeof(info.x86_capability)))
return;
pr_warn("x86/CPU: CPU features have changed after loading microcode, but might not take effect.\n");
pr_warn("x86/CPU: Please consider either early loading through initrd/built-in or a potential BIOS update.\n");
}