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linux/arch/x86/kernel/cpu/intel.c
Linus Torvalds 97d052ea3f A set of locking fixes and updates: 
- Untangle the header spaghetti which causes build failures in various
     situations caused by the lockdep additions to seqcount to validate that
     the write side critical sections are non-preemptible.
 
   - The seqcount associated lock debug addons which were blocked by the
     above fallout.
 
     seqcount writers contrary to seqlock writers must be externally
     serialized, which usually happens via locking - except for strict per
     CPU seqcounts. As the lock is not part of the seqcount, lockdep cannot
     validate that the lock is held.
 
     This new debug mechanism adds the concept of associated locks.
     sequence count has now lock type variants and corresponding
     initializers which take a pointer to the associated lock used for
     writer serialization. If lockdep is enabled the pointer is stored and
     write_seqcount_begin() has a lockdep assertion to validate that the
     lock is held.
 
     Aside of the type and the initializer no other code changes are
     required at the seqcount usage sites. The rest of the seqcount API is
     unchanged and determines the type at compile time with the help of
     _Generic which is possible now that the minimal GCC version has been
     moved up.
 
     Adding this lockdep coverage unearthed a handful of seqcount bugs which
     have been addressed already independent of this.
 
     While generaly useful this comes with a Trojan Horse twist: On RT
     kernels the write side critical section can become preemtible if the
     writers are serialized by an associated lock, which leads to the well
     known reader preempts writer livelock. RT prevents this by storing the
     associated lock pointer independent of lockdep in the seqcount and
     changing the reader side to block on the lock when a reader detects
     that a writer is in the write side critical section.
 
  - Conversion of seqcount usage sites to associated types and initializers.
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Merge tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Thomas Gleixner:
 "A set of locking fixes and updates:

   - Untangle the header spaghetti which causes build failures in
     various situations caused by the lockdep additions to seqcount to
     validate that the write side critical sections are non-preemptible.

   - The seqcount associated lock debug addons which were blocked by the
     above fallout.

     seqcount writers contrary to seqlock writers must be externally
     serialized, which usually happens via locking - except for strict
     per CPU seqcounts. As the lock is not part of the seqcount, lockdep
     cannot validate that the lock is held.

     This new debug mechanism adds the concept of associated locks.
     sequence count has now lock type variants and corresponding
     initializers which take a pointer to the associated lock used for
     writer serialization. If lockdep is enabled the pointer is stored
     and write_seqcount_begin() has a lockdep assertion to validate that
     the lock is held.

     Aside of the type and the initializer no other code changes are
     required at the seqcount usage sites. The rest of the seqcount API
     is unchanged and determines the type at compile time with the help
     of _Generic which is possible now that the minimal GCC version has
     been moved up.

     Adding this lockdep coverage unearthed a handful of seqcount bugs
     which have been addressed already independent of this.

     While generally useful this comes with a Trojan Horse twist: On RT
     kernels the write side critical section can become preemtible if
     the writers are serialized by an associated lock, which leads to
     the well known reader preempts writer livelock. RT prevents this by
     storing the associated lock pointer independent of lockdep in the
     seqcount and changing the reader side to block on the lock when a
     reader detects that a writer is in the write side critical section.

   - Conversion of seqcount usage sites to associated types and
     initializers"

* tag 'locking-urgent-2020-08-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  locking/seqlock, headers: Untangle the spaghetti monster
  locking, arch/ia64: Reduce <asm/smp.h> header dependencies by moving XTP bits into the new <asm/xtp.h> header
  x86/headers: Remove APIC headers from <asm/smp.h>
  seqcount: More consistent seqprop names
  seqcount: Compress SEQCNT_LOCKNAME_ZERO()
  seqlock: Fold seqcount_LOCKNAME_init() definition
  seqlock: Fold seqcount_LOCKNAME_t definition
  seqlock: s/__SEQ_LOCKDEP/__SEQ_LOCK/g
  hrtimer: Use sequence counter with associated raw spinlock
  kvm/eventfd: Use sequence counter with associated spinlock
  userfaultfd: Use sequence counter with associated spinlock
  NFSv4: Use sequence counter with associated spinlock
  iocost: Use sequence counter with associated spinlock
  raid5: Use sequence counter with associated spinlock
  vfs: Use sequence counter with associated spinlock
  timekeeping: Use sequence counter with associated raw spinlock
  xfrm: policy: Use sequence counters with associated lock
  netfilter: nft_set_rbtree: Use sequence counter with associated rwlock
  netfilter: conntrack: Use sequence counter with associated spinlock
  sched: tasks: Use sequence counter with associated spinlock
  ...
2020-08-10 19:07:44 -07:00

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// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/pgtable.h>
#include <linux/string.h>
#include <linux/bitops.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/sched/clock.h>
#include <linux/thread_info.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <asm/cpufeature.h>
#include <asm/msr.h>
#include <asm/bugs.h>
#include <asm/cpu.h>
#include <asm/intel-family.h>
#include <asm/microcode_intel.h>
#include <asm/hwcap2.h>
#include <asm/elf.h>
#include <asm/cpu_device_id.h>
#include <asm/cmdline.h>
#include <asm/traps.h>
#include <asm/resctrl.h>
#include <asm/numa.h>
#ifdef CONFIG_X86_64
#include <linux/topology.h>
#endif
#include "cpu.h"
#ifdef CONFIG_X86_LOCAL_APIC
#include <asm/mpspec.h>
#include <asm/apic.h>
#endif
enum split_lock_detect_state {
sld_off = 0,
sld_warn,
sld_fatal,
};
/*
* Default to sld_off because most systems do not support split lock detection
* split_lock_setup() will switch this to sld_warn on systems that support
* split lock detect, unless there is a command line override.
*/
static enum split_lock_detect_state sld_state __ro_after_init = sld_off;
static u64 msr_test_ctrl_cache __ro_after_init;
/*
* With a name like MSR_TEST_CTL it should go without saying, but don't touch
* MSR_TEST_CTL unless the CPU is one of the whitelisted models. Writing it
* on CPUs that do not support SLD can cause fireworks, even when writing '0'.
*/
static bool cpu_model_supports_sld __ro_after_init;
/*
* Processors which have self-snooping capability can handle conflicting
* memory type across CPUs by snooping its own cache. However, there exists
* CPU models in which having conflicting memory types still leads to
* unpredictable behavior, machine check errors, or hangs. Clear this
* feature to prevent its use on machines with known erratas.
*/
static void check_memory_type_self_snoop_errata(struct cpuinfo_x86 *c)
{
switch (c->x86_model) {
case INTEL_FAM6_CORE_YONAH:
case INTEL_FAM6_CORE2_MEROM:
case INTEL_FAM6_CORE2_MEROM_L:
case INTEL_FAM6_CORE2_PENRYN:
case INTEL_FAM6_CORE2_DUNNINGTON:
case INTEL_FAM6_NEHALEM:
case INTEL_FAM6_NEHALEM_G:
case INTEL_FAM6_NEHALEM_EP:
case INTEL_FAM6_NEHALEM_EX:
case INTEL_FAM6_WESTMERE:
case INTEL_FAM6_WESTMERE_EP:
case INTEL_FAM6_SANDYBRIDGE:
setup_clear_cpu_cap(X86_FEATURE_SELFSNOOP);
}
}
static bool ring3mwait_disabled __read_mostly;
static int __init ring3mwait_disable(char *__unused)
{
ring3mwait_disabled = true;
return 0;
}
__setup("ring3mwait=disable", ring3mwait_disable);
static void probe_xeon_phi_r3mwait(struct cpuinfo_x86 *c)
{
/*
* Ring 3 MONITOR/MWAIT feature cannot be detected without
* cpu model and family comparison.
*/
if (c->x86 != 6)
return;
switch (c->x86_model) {
case INTEL_FAM6_XEON_PHI_KNL:
case INTEL_FAM6_XEON_PHI_KNM:
break;
default:
return;
}
if (ring3mwait_disabled)
return;
set_cpu_cap(c, X86_FEATURE_RING3MWAIT);
this_cpu_or(msr_misc_features_shadow,
1UL << MSR_MISC_FEATURES_ENABLES_RING3MWAIT_BIT);
if (c == &boot_cpu_data)
ELF_HWCAP2 |= HWCAP2_RING3MWAIT;
}
/*
* Early microcode releases for the Spectre v2 mitigation were broken.
* Information taken from;
* - https://newsroom.intel.com/wp-content/uploads/sites/11/2018/03/microcode-update-guidance.pdf
* - https://kb.vmware.com/s/article/52345
* - Microcode revisions observed in the wild
* - Release note from 20180108 microcode release
*/
struct sku_microcode {
u8 model;
u8 stepping;
u32 microcode;
};
static const struct sku_microcode spectre_bad_microcodes[] = {
{ INTEL_FAM6_KABYLAKE, 0x0B, 0x80 },
{ INTEL_FAM6_KABYLAKE, 0x0A, 0x80 },
{ INTEL_FAM6_KABYLAKE, 0x09, 0x80 },
{ INTEL_FAM6_KABYLAKE_L, 0x0A, 0x80 },
{ INTEL_FAM6_KABYLAKE_L, 0x09, 0x80 },
{ INTEL_FAM6_SKYLAKE_X, 0x03, 0x0100013e },
{ INTEL_FAM6_SKYLAKE_X, 0x04, 0x0200003c },
{ INTEL_FAM6_BROADWELL, 0x04, 0x28 },
{ INTEL_FAM6_BROADWELL_G, 0x01, 0x1b },
{ INTEL_FAM6_BROADWELL_D, 0x02, 0x14 },
{ INTEL_FAM6_BROADWELL_D, 0x03, 0x07000011 },
{ INTEL_FAM6_BROADWELL_X, 0x01, 0x0b000025 },
{ INTEL_FAM6_HASWELL_L, 0x01, 0x21 },
{ INTEL_FAM6_HASWELL_G, 0x01, 0x18 },
{ INTEL_FAM6_HASWELL, 0x03, 0x23 },
{ INTEL_FAM6_HASWELL_X, 0x02, 0x3b },
{ INTEL_FAM6_HASWELL_X, 0x04, 0x10 },
{ INTEL_FAM6_IVYBRIDGE_X, 0x04, 0x42a },
/* Observed in the wild */
{ INTEL_FAM6_SANDYBRIDGE_X, 0x06, 0x61b },
{ INTEL_FAM6_SANDYBRIDGE_X, 0x07, 0x712 },
};
static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
{
int i;
/*
* We know that the hypervisor lie to us on the microcode version so
* we may as well hope that it is running the correct version.
*/
if (cpu_has(c, X86_FEATURE_HYPERVISOR))
return false;
if (c->x86 != 6)
return false;
for (i = 0; i < ARRAY_SIZE(spectre_bad_microcodes); i++) {
if (c->x86_model == spectre_bad_microcodes[i].model &&
c->x86_stepping == spectre_bad_microcodes[i].stepping)
return (c->microcode <= spectre_bad_microcodes[i].microcode);
}
return false;
}
static void early_init_intel(struct cpuinfo_x86 *c)
{
u64 misc_enable;
/* Unmask CPUID levels if masked: */
if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) {
if (msr_clear_bit(MSR_IA32_MISC_ENABLE,
MSR_IA32_MISC_ENABLE_LIMIT_CPUID_BIT) > 0) {
c->cpuid_level = cpuid_eax(0);
get_cpu_cap(c);
}
}
if ((c->x86 == 0xf && c->x86_model >= 0x03) ||
(c->x86 == 0x6 && c->x86_model >= 0x0e))
set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
if (c->x86 >= 6 && !cpu_has(c, X86_FEATURE_IA64))
c->microcode = intel_get_microcode_revision();
/* Now if any of them are set, check the blacklist and clear the lot */
if ((cpu_has(c, X86_FEATURE_SPEC_CTRL) ||
cpu_has(c, X86_FEATURE_INTEL_STIBP) ||
cpu_has(c, X86_FEATURE_IBRS) || cpu_has(c, X86_FEATURE_IBPB) ||
cpu_has(c, X86_FEATURE_STIBP)) && bad_spectre_microcode(c)) {
pr_warn("Intel Spectre v2 broken microcode detected; disabling Speculation Control\n");
setup_clear_cpu_cap(X86_FEATURE_IBRS);
setup_clear_cpu_cap(X86_FEATURE_IBPB);
setup_clear_cpu_cap(X86_FEATURE_STIBP);
setup_clear_cpu_cap(X86_FEATURE_SPEC_CTRL);
setup_clear_cpu_cap(X86_FEATURE_MSR_SPEC_CTRL);
setup_clear_cpu_cap(X86_FEATURE_INTEL_STIBP);
setup_clear_cpu_cap(X86_FEATURE_SSBD);
setup_clear_cpu_cap(X86_FEATURE_SPEC_CTRL_SSBD);
}
/*
* Atom erratum AAE44/AAF40/AAG38/AAH41:
*
* A race condition between speculative fetches and invalidating
* a large page. This is worked around in microcode, but we
* need the microcode to have already been loaded... so if it is
* not, recommend a BIOS update and disable large pages.
*/
if (c->x86 == 6 && c->x86_model == 0x1c && c->x86_stepping <= 2 &&
c->microcode < 0x20e) {
pr_warn("Atom PSE erratum detected, BIOS microcode update recommended\n");
clear_cpu_cap(c, X86_FEATURE_PSE);
}
#ifdef CONFIG_X86_64
set_cpu_cap(c, X86_FEATURE_SYSENTER32);
#else
/* Netburst reports 64 bytes clflush size, but does IO in 128 bytes */
if (c->x86 == 15 && c->x86_cache_alignment == 64)
c->x86_cache_alignment = 128;
#endif
/* CPUID workaround for 0F33/0F34 CPU */
if (c->x86 == 0xF && c->x86_model == 0x3
&& (c->x86_stepping == 0x3 || c->x86_stepping == 0x4))
c->x86_phys_bits = 36;
/*
* c->x86_power is 8000_0007 edx. Bit 8 is TSC runs at constant rate
* with P/T states and does not stop in deep C-states.
*
* It is also reliable across cores and sockets. (but not across
* cabinets - we turn it off in that case explicitly.)
*/
if (c->x86_power & (1 << 8)) {
set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC);
}
/* Penwell and Cloverview have the TSC which doesn't sleep on S3 */
if (c->x86 == 6) {
switch (c->x86_model) {
case INTEL_FAM6_ATOM_SALTWELL_MID:
case INTEL_FAM6_ATOM_SALTWELL_TABLET:
case INTEL_FAM6_ATOM_SILVERMONT_MID:
case INTEL_FAM6_ATOM_AIRMONT_NP:
set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC_S3);
break;
default:
break;
}
}
/*
* There is a known erratum on Pentium III and Core Solo
* and Core Duo CPUs.
* " Page with PAT set to WC while associated MTRR is UC
* may consolidate to UC "
* Because of this erratum, it is better to stick with
* setting WC in MTRR rather than using PAT on these CPUs.
*
* Enable PAT WC only on P4, Core 2 or later CPUs.
*/
if (c->x86 == 6 && c->x86_model < 15)
clear_cpu_cap(c, X86_FEATURE_PAT);
/*
* If fast string is not enabled in IA32_MISC_ENABLE for any reason,
* clear the fast string and enhanced fast string CPU capabilities.
*/
if (c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xd)) {
rdmsrl(MSR_IA32_MISC_ENABLE, misc_enable);
if (!(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) {
pr_info("Disabled fast string operations\n");
setup_clear_cpu_cap(X86_FEATURE_REP_GOOD);
setup_clear_cpu_cap(X86_FEATURE_ERMS);
}
}
/*
* Intel Quark Core DevMan_001.pdf section 6.4.11
* "The operating system also is required to invalidate (i.e., flush)
* the TLB when any changes are made to any of the page table entries.
* The operating system must reload CR3 to cause the TLB to be flushed"
*
* As a result, boot_cpu_has(X86_FEATURE_PGE) in arch/x86/include/asm/tlbflush.h
* should be false so that __flush_tlb_all() causes CR3 insted of CR4.PGE
* to be modified.
*/
if (c->x86 == 5 && c->x86_model == 9) {
pr_info("Disabling PGE capability bit\n");
setup_clear_cpu_cap(X86_FEATURE_PGE);
}
if (c->cpuid_level >= 0x00000001) {
u32 eax, ebx, ecx, edx;
cpuid(0x00000001, &eax, &ebx, &ecx, &edx);
/*
* If HTT (EDX[28]) is set EBX[16:23] contain the number of
* apicids which are reserved per package. Store the resulting
* shift value for the package management code.
*/
if (edx & (1U << 28))
c->x86_coreid_bits = get_count_order((ebx >> 16) & 0xff);
}
check_memory_type_self_snoop_errata(c);
/*
* Get the number of SMT siblings early from the extended topology
* leaf, if available. Otherwise try the legacy SMT detection.
*/
if (detect_extended_topology_early(c) < 0)
detect_ht_early(c);
}
static void bsp_init_intel(struct cpuinfo_x86 *c)
{
resctrl_cpu_detect(c);
}
#ifdef CONFIG_X86_32
/*
* Early probe support logic for ppro memory erratum #50
*
* This is called before we do cpu ident work
*/
int ppro_with_ram_bug(void)
{
/* Uses data from early_cpu_detect now */
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
boot_cpu_data.x86 == 6 &&
boot_cpu_data.x86_model == 1 &&
boot_cpu_data.x86_stepping < 8) {
pr_info("Pentium Pro with Errata#50 detected. Taking evasive action.\n");
return 1;
}
return 0;
}
static void intel_smp_check(struct cpuinfo_x86 *c)
{
/* calling is from identify_secondary_cpu() ? */
if (!c->cpu_index)
return;
/*
* Mask B, Pentium, but not Pentium MMX
*/
if (c->x86 == 5 &&
c->x86_stepping >= 1 && c->x86_stepping <= 4 &&
c->x86_model <= 3) {
/*
* Remember we have B step Pentia with bugs
*/
WARN_ONCE(1, "WARNING: SMP operation may be unreliable"
"with B stepping processors.\n");
}
}
static int forcepae;
static int __init forcepae_setup(char *__unused)
{
forcepae = 1;
return 1;
}
__setup("forcepae", forcepae_setup);
static void intel_workarounds(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_F00F_BUG
/*
* All models of Pentium and Pentium with MMX technology CPUs
* have the F0 0F bug, which lets nonprivileged users lock up the
* system. Announce that the fault handler will be checking for it.
* The Quark is also family 5, but does not have the same bug.
*/
clear_cpu_bug(c, X86_BUG_F00F);
if (c->x86 == 5 && c->x86_model < 9) {
static int f00f_workaround_enabled;
set_cpu_bug(c, X86_BUG_F00F);
if (!f00f_workaround_enabled) {
pr_notice("Intel Pentium with F0 0F bug - workaround enabled.\n");
f00f_workaround_enabled = 1;
}
}
#endif
/*
* SEP CPUID bug: Pentium Pro reports SEP but doesn't have it until
* model 3 mask 3
*/
if ((c->x86<<8 | c->x86_model<<4 | c->x86_stepping) < 0x633)
clear_cpu_cap(c, X86_FEATURE_SEP);
/*
* PAE CPUID issue: many Pentium M report no PAE but may have a
* functionally usable PAE implementation.
* Forcefully enable PAE if kernel parameter "forcepae" is present.
*/
if (forcepae) {
pr_warn("PAE forced!\n");
set_cpu_cap(c, X86_FEATURE_PAE);
add_taint(TAINT_CPU_OUT_OF_SPEC, LOCKDEP_NOW_UNRELIABLE);
}
/*
* P4 Xeon erratum 037 workaround.
* Hardware prefetcher may cause stale data to be loaded into the cache.
*/
if ((c->x86 == 15) && (c->x86_model == 1) && (c->x86_stepping == 1)) {
if (msr_set_bit(MSR_IA32_MISC_ENABLE,
MSR_IA32_MISC_ENABLE_PREFETCH_DISABLE_BIT) > 0) {
pr_info("CPU: C0 stepping P4 Xeon detected.\n");
pr_info("CPU: Disabling hardware prefetching (Erratum 037)\n");
}
}
/*
* See if we have a good local APIC by checking for buggy Pentia,
* i.e. all B steppings and the C2 stepping of P54C when using their
* integrated APIC (see 11AP erratum in "Pentium Processor
* Specification Update").
*/
if (boot_cpu_has(X86_FEATURE_APIC) && (c->x86<<8 | c->x86_model<<4) == 0x520 &&
(c->x86_stepping < 0x6 || c->x86_stepping == 0xb))
set_cpu_bug(c, X86_BUG_11AP);
#ifdef CONFIG_X86_INTEL_USERCOPY
/*
* Set up the preferred alignment for movsl bulk memory moves
*/
switch (c->x86) {
case 4: /* 486: untested */
break;
case 5: /* Old Pentia: untested */
break;
case 6: /* PII/PIII only like movsl with 8-byte alignment */
movsl_mask.mask = 7;
break;
case 15: /* P4 is OK down to 8-byte alignment */
movsl_mask.mask = 7;
break;
}
#endif
intel_smp_check(c);
}
#else
static void intel_workarounds(struct cpuinfo_x86 *c)
{
}
#endif
static void srat_detect_node(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_NUMA
unsigned node;
int cpu = smp_processor_id();
/* Don't do the funky fallback heuristics the AMD version employs
for now. */
node = numa_cpu_node(cpu);
if (node == NUMA_NO_NODE || !node_online(node)) {
/* reuse the value from init_cpu_to_node() */
node = cpu_to_node(cpu);
}
numa_set_node(cpu, node);
#endif
}
#define MSR_IA32_TME_ACTIVATE 0x982
/* Helpers to access TME_ACTIVATE MSR */
#define TME_ACTIVATE_LOCKED(x) (x & 0x1)
#define TME_ACTIVATE_ENABLED(x) (x & 0x2)
#define TME_ACTIVATE_POLICY(x) ((x >> 4) & 0xf) /* Bits 7:4 */
#define TME_ACTIVATE_POLICY_AES_XTS_128 0
#define TME_ACTIVATE_KEYID_BITS(x) ((x >> 32) & 0xf) /* Bits 35:32 */
#define TME_ACTIVATE_CRYPTO_ALGS(x) ((x >> 48) & 0xffff) /* Bits 63:48 */
#define TME_ACTIVATE_CRYPTO_AES_XTS_128 1
/* Values for mktme_status (SW only construct) */
#define MKTME_ENABLED 0
#define MKTME_DISABLED 1
#define MKTME_UNINITIALIZED 2
static int mktme_status = MKTME_UNINITIALIZED;
static void detect_tme(struct cpuinfo_x86 *c)
{
u64 tme_activate, tme_policy, tme_crypto_algs;
int keyid_bits = 0, nr_keyids = 0;
static u64 tme_activate_cpu0 = 0;
rdmsrl(MSR_IA32_TME_ACTIVATE, tme_activate);
if (mktme_status != MKTME_UNINITIALIZED) {
if (tme_activate != tme_activate_cpu0) {
/* Broken BIOS? */
pr_err_once("x86/tme: configuration is inconsistent between CPUs\n");
pr_err_once("x86/tme: MKTME is not usable\n");
mktme_status = MKTME_DISABLED;
/* Proceed. We may need to exclude bits from x86_phys_bits. */
}
} else {
tme_activate_cpu0 = tme_activate;
}
if (!TME_ACTIVATE_LOCKED(tme_activate) || !TME_ACTIVATE_ENABLED(tme_activate)) {
pr_info_once("x86/tme: not enabled by BIOS\n");
mktme_status = MKTME_DISABLED;
return;
}
if (mktme_status != MKTME_UNINITIALIZED)
goto detect_keyid_bits;
pr_info("x86/tme: enabled by BIOS\n");
tme_policy = TME_ACTIVATE_POLICY(tme_activate);
if (tme_policy != TME_ACTIVATE_POLICY_AES_XTS_128)
pr_warn("x86/tme: Unknown policy is active: %#llx\n", tme_policy);
tme_crypto_algs = TME_ACTIVATE_CRYPTO_ALGS(tme_activate);
if (!(tme_crypto_algs & TME_ACTIVATE_CRYPTO_AES_XTS_128)) {
pr_err("x86/mktme: No known encryption algorithm is supported: %#llx\n",
tme_crypto_algs);
mktme_status = MKTME_DISABLED;
}
detect_keyid_bits:
keyid_bits = TME_ACTIVATE_KEYID_BITS(tme_activate);
nr_keyids = (1UL << keyid_bits) - 1;
if (nr_keyids) {
pr_info_once("x86/mktme: enabled by BIOS\n");
pr_info_once("x86/mktme: %d KeyIDs available\n", nr_keyids);
} else {
pr_info_once("x86/mktme: disabled by BIOS\n");
}
if (mktme_status == MKTME_UNINITIALIZED) {
/* MKTME is usable */
mktme_status = MKTME_ENABLED;
}
/*
* KeyID bits effectively lower the number of physical address
* bits. Update cpuinfo_x86::x86_phys_bits accordingly.
*/
c->x86_phys_bits -= keyid_bits;
}
static void init_cpuid_fault(struct cpuinfo_x86 *c)
{
u64 msr;
if (!rdmsrl_safe(MSR_PLATFORM_INFO, &msr)) {
if (msr & MSR_PLATFORM_INFO_CPUID_FAULT)
set_cpu_cap(c, X86_FEATURE_CPUID_FAULT);
}
}
static void init_intel_misc_features(struct cpuinfo_x86 *c)
{
u64 msr;
if (rdmsrl_safe(MSR_MISC_FEATURES_ENABLES, &msr))
return;
/* Clear all MISC features */
this_cpu_write(msr_misc_features_shadow, 0);
/* Check features and update capabilities and shadow control bits */
init_cpuid_fault(c);
probe_xeon_phi_r3mwait(c);
msr = this_cpu_read(msr_misc_features_shadow);
wrmsrl(MSR_MISC_FEATURES_ENABLES, msr);
}
static void split_lock_init(void);
static void init_intel(struct cpuinfo_x86 *c)
{
early_init_intel(c);
intel_workarounds(c);
/*
* Detect the extended topology information if available. This
* will reinitialise the initial_apicid which will be used
* in init_intel_cacheinfo()
*/
detect_extended_topology(c);
if (!cpu_has(c, X86_FEATURE_XTOPOLOGY)) {
/*
* let's use the legacy cpuid vector 0x1 and 0x4 for topology
* detection.
*/
detect_num_cpu_cores(c);
#ifdef CONFIG_X86_32
detect_ht(c);
#endif
}
init_intel_cacheinfo(c);
if (c->cpuid_level > 9) {
unsigned eax = cpuid_eax(10);
/* Check for version and the number of counters */
if ((eax & 0xff) && (((eax>>8) & 0xff) > 1))
set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
}
if (cpu_has(c, X86_FEATURE_XMM2))
set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
if (boot_cpu_has(X86_FEATURE_DS)) {
unsigned int l1, l2;
rdmsr(MSR_IA32_MISC_ENABLE, l1, l2);
if (!(l1 & (1<<11)))
set_cpu_cap(c, X86_FEATURE_BTS);
if (!(l1 & (1<<12)))
set_cpu_cap(c, X86_FEATURE_PEBS);
}
if (c->x86 == 6 && boot_cpu_has(X86_FEATURE_CLFLUSH) &&
(c->x86_model == 29 || c->x86_model == 46 || c->x86_model == 47))
set_cpu_bug(c, X86_BUG_CLFLUSH_MONITOR);
if (c->x86 == 6 && boot_cpu_has(X86_FEATURE_MWAIT) &&
((c->x86_model == INTEL_FAM6_ATOM_GOLDMONT)))
set_cpu_bug(c, X86_BUG_MONITOR);
#ifdef CONFIG_X86_64
if (c->x86 == 15)
c->x86_cache_alignment = c->x86_clflush_size * 2;
if (c->x86 == 6)
set_cpu_cap(c, X86_FEATURE_REP_GOOD);
#else
/*
* Names for the Pentium II/Celeron processors
* detectable only by also checking the cache size.
* Dixon is NOT a Celeron.
*/
if (c->x86 == 6) {
unsigned int l2 = c->x86_cache_size;
char *p = NULL;
switch (c->x86_model) {
case 5:
if (l2 == 0)
p = "Celeron (Covington)";
else if (l2 == 256)
p = "Mobile Pentium II (Dixon)";
break;
case 6:
if (l2 == 128)
p = "Celeron (Mendocino)";
else if (c->x86_stepping == 0 || c->x86_stepping == 5)
p = "Celeron-A";
break;
case 8:
if (l2 == 128)
p = "Celeron (Coppermine)";
break;
}
if (p)
strcpy(c->x86_model_id, p);
}
if (c->x86 == 15)
set_cpu_cap(c, X86_FEATURE_P4);
if (c->x86 == 6)
set_cpu_cap(c, X86_FEATURE_P3);
#endif
/* Work around errata */
srat_detect_node(c);
init_ia32_feat_ctl(c);
if (cpu_has(c, X86_FEATURE_TME))
detect_tme(c);
init_intel_misc_features(c);
if (tsx_ctrl_state == TSX_CTRL_ENABLE)
tsx_enable();
if (tsx_ctrl_state == TSX_CTRL_DISABLE)
tsx_disable();
split_lock_init();
}
#ifdef CONFIG_X86_32
static unsigned int intel_size_cache(struct cpuinfo_x86 *c, unsigned int size)
{
/*
* Intel PIII Tualatin. This comes in two flavours.
* One has 256kb of cache, the other 512. We have no way
* to determine which, so we use a boottime override
* for the 512kb model, and assume 256 otherwise.
*/
if ((c->x86 == 6) && (c->x86_model == 11) && (size == 0))
size = 256;
/*
* Intel Quark SoC X1000 contains a 4-way set associative
* 16K cache with a 16 byte cache line and 256 lines per tag
*/
if ((c->x86 == 5) && (c->x86_model == 9))
size = 16;
return size;
}
#endif
#define TLB_INST_4K 0x01
#define TLB_INST_4M 0x02
#define TLB_INST_2M_4M 0x03
#define TLB_INST_ALL 0x05
#define TLB_INST_1G 0x06
#define TLB_DATA_4K 0x11
#define TLB_DATA_4M 0x12
#define TLB_DATA_2M_4M 0x13
#define TLB_DATA_4K_4M 0x14
#define TLB_DATA_1G 0x16
#define TLB_DATA0_4K 0x21
#define TLB_DATA0_4M 0x22
#define TLB_DATA0_2M_4M 0x23
#define STLB_4K 0x41
#define STLB_4K_2M 0x42
static const struct _tlb_table intel_tlb_table[] = {
{ 0x01, TLB_INST_4K, 32, " TLB_INST 4 KByte pages, 4-way set associative" },
{ 0x02, TLB_INST_4M, 2, " TLB_INST 4 MByte pages, full associative" },
{ 0x03, TLB_DATA_4K, 64, " TLB_DATA 4 KByte pages, 4-way set associative" },
{ 0x04, TLB_DATA_4M, 8, " TLB_DATA 4 MByte pages, 4-way set associative" },
{ 0x05, TLB_DATA_4M, 32, " TLB_DATA 4 MByte pages, 4-way set associative" },
{ 0x0b, TLB_INST_4M, 4, " TLB_INST 4 MByte pages, 4-way set associative" },
{ 0x4f, TLB_INST_4K, 32, " TLB_INST 4 KByte pages" },
{ 0x50, TLB_INST_ALL, 64, " TLB_INST 4 KByte and 2-MByte or 4-MByte pages" },
{ 0x51, TLB_INST_ALL, 128, " TLB_INST 4 KByte and 2-MByte or 4-MByte pages" },
{ 0x52, TLB_INST_ALL, 256, " TLB_INST 4 KByte and 2-MByte or 4-MByte pages" },
{ 0x55, TLB_INST_2M_4M, 7, " TLB_INST 2-MByte or 4-MByte pages, fully associative" },
{ 0x56, TLB_DATA0_4M, 16, " TLB_DATA0 4 MByte pages, 4-way set associative" },
{ 0x57, TLB_DATA0_4K, 16, " TLB_DATA0 4 KByte pages, 4-way associative" },
{ 0x59, TLB_DATA0_4K, 16, " TLB_DATA0 4 KByte pages, fully associative" },
{ 0x5a, TLB_DATA0_2M_4M, 32, " TLB_DATA0 2-MByte or 4 MByte pages, 4-way set associative" },
{ 0x5b, TLB_DATA_4K_4M, 64, " TLB_DATA 4 KByte and 4 MByte pages" },
{ 0x5c, TLB_DATA_4K_4M, 128, " TLB_DATA 4 KByte and 4 MByte pages" },
{ 0x5d, TLB_DATA_4K_4M, 256, " TLB_DATA 4 KByte and 4 MByte pages" },
{ 0x61, TLB_INST_4K, 48, " TLB_INST 4 KByte pages, full associative" },
{ 0x63, TLB_DATA_1G, 4, " TLB_DATA 1 GByte pages, 4-way set associative" },
{ 0x6b, TLB_DATA_4K, 256, " TLB_DATA 4 KByte pages, 8-way associative" },
{ 0x6c, TLB_DATA_2M_4M, 128, " TLB_DATA 2 MByte or 4 MByte pages, 8-way associative" },
{ 0x6d, TLB_DATA_1G, 16, " TLB_DATA 1 GByte pages, fully associative" },
{ 0x76, TLB_INST_2M_4M, 8, " TLB_INST 2-MByte or 4-MByte pages, fully associative" },
{ 0xb0, TLB_INST_4K, 128, " TLB_INST 4 KByte pages, 4-way set associative" },
{ 0xb1, TLB_INST_2M_4M, 4, " TLB_INST 2M pages, 4-way, 8 entries or 4M pages, 4-way entries" },
{ 0xb2, TLB_INST_4K, 64, " TLB_INST 4KByte pages, 4-way set associative" },
{ 0xb3, TLB_DATA_4K, 128, " TLB_DATA 4 KByte pages, 4-way set associative" },
{ 0xb4, TLB_DATA_4K, 256, " TLB_DATA 4 KByte pages, 4-way associative" },
{ 0xb5, TLB_INST_4K, 64, " TLB_INST 4 KByte pages, 8-way set associative" },
{ 0xb6, TLB_INST_4K, 128, " TLB_INST 4 KByte pages, 8-way set associative" },
{ 0xba, TLB_DATA_4K, 64, " TLB_DATA 4 KByte pages, 4-way associative" },
{ 0xc0, TLB_DATA_4K_4M, 8, " TLB_DATA 4 KByte and 4 MByte pages, 4-way associative" },
{ 0xc1, STLB_4K_2M, 1024, " STLB 4 KByte and 2 MByte pages, 8-way associative" },
{ 0xc2, TLB_DATA_2M_4M, 16, " TLB_DATA 2 MByte/4MByte pages, 4-way associative" },
{ 0xca, STLB_4K, 512, " STLB 4 KByte pages, 4-way associative" },
{ 0x00, 0, 0 }
};
static void intel_tlb_lookup(const unsigned char desc)
{
unsigned char k;
if (desc == 0)
return;
/* look up this descriptor in the table */
for (k = 0; intel_tlb_table[k].descriptor != desc &&
intel_tlb_table[k].descriptor != 0; k++)
;
if (intel_tlb_table[k].tlb_type == 0)
return;
switch (intel_tlb_table[k].tlb_type) {
case STLB_4K:
if (tlb_lli_4k[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_4k[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lld_4k[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_4k[ENTRIES] = intel_tlb_table[k].entries;
break;
case STLB_4K_2M:
if (tlb_lli_4k[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_4k[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lld_4k[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_4k[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lli_2m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_2m[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lld_2m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_2m[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lli_4m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_4m[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lld_4m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_4m[ENTRIES] = intel_tlb_table[k].entries;
break;
case TLB_INST_ALL:
if (tlb_lli_4k[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_4k[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lli_2m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_2m[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lli_4m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_4m[ENTRIES] = intel_tlb_table[k].entries;
break;
case TLB_INST_4K:
if (tlb_lli_4k[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_4k[ENTRIES] = intel_tlb_table[k].entries;
break;
case TLB_INST_4M:
if (tlb_lli_4m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_4m[ENTRIES] = intel_tlb_table[k].entries;
break;
case TLB_INST_2M_4M:
if (tlb_lli_2m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_2m[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lli_4m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lli_4m[ENTRIES] = intel_tlb_table[k].entries;
break;
case TLB_DATA_4K:
case TLB_DATA0_4K:
if (tlb_lld_4k[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_4k[ENTRIES] = intel_tlb_table[k].entries;
break;
case TLB_DATA_4M:
case TLB_DATA0_4M:
if (tlb_lld_4m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_4m[ENTRIES] = intel_tlb_table[k].entries;
break;
case TLB_DATA_2M_4M:
case TLB_DATA0_2M_4M:
if (tlb_lld_2m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_2m[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lld_4m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_4m[ENTRIES] = intel_tlb_table[k].entries;
break;
case TLB_DATA_4K_4M:
if (tlb_lld_4k[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_4k[ENTRIES] = intel_tlb_table[k].entries;
if (tlb_lld_4m[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_4m[ENTRIES] = intel_tlb_table[k].entries;
break;
case TLB_DATA_1G:
if (tlb_lld_1g[ENTRIES] < intel_tlb_table[k].entries)
tlb_lld_1g[ENTRIES] = intel_tlb_table[k].entries;
break;
}
}
static void intel_detect_tlb(struct cpuinfo_x86 *c)
{
int i, j, n;
unsigned int regs[4];
unsigned char *desc = (unsigned char *)regs;
if (c->cpuid_level < 2)
return;
/* Number of times to iterate */
n = cpuid_eax(2) & 0xFF;
for (i = 0 ; i < n ; i++) {
cpuid(2, &regs[0], &regs[1], &regs[2], &regs[3]);
/* If bit 31 is set, this is an unknown format */
for (j = 0 ; j < 3 ; j++)
if (regs[j] & (1 << 31))
regs[j] = 0;
/* Byte 0 is level count, not a descriptor */
for (j = 1 ; j < 16 ; j++)
intel_tlb_lookup(desc[j]);
}
}
static const struct cpu_dev intel_cpu_dev = {
.c_vendor = "Intel",
.c_ident = { "GenuineIntel" },
#ifdef CONFIG_X86_32
.legacy_models = {
{ .family = 4, .model_names =
{
[0] = "486 DX-25/33",
[1] = "486 DX-50",
[2] = "486 SX",
[3] = "486 DX/2",
[4] = "486 SL",
[5] = "486 SX/2",
[7] = "486 DX/2-WB",
[8] = "486 DX/4",
[9] = "486 DX/4-WB"
}
},
{ .family = 5, .model_names =
{
[0] = "Pentium 60/66 A-step",
[1] = "Pentium 60/66",
[2] = "Pentium 75 - 200",
[3] = "OverDrive PODP5V83",
[4] = "Pentium MMX",
[7] = "Mobile Pentium 75 - 200",
[8] = "Mobile Pentium MMX",
[9] = "Quark SoC X1000",
}
},
{ .family = 6, .model_names =
{
[0] = "Pentium Pro A-step",
[1] = "Pentium Pro",
[3] = "Pentium II (Klamath)",
[4] = "Pentium II (Deschutes)",
[5] = "Pentium II (Deschutes)",
[6] = "Mobile Pentium II",
[7] = "Pentium III (Katmai)",
[8] = "Pentium III (Coppermine)",
[10] = "Pentium III (Cascades)",
[11] = "Pentium III (Tualatin)",
}
},
{ .family = 15, .model_names =
{
[0] = "Pentium 4 (Unknown)",
[1] = "Pentium 4 (Willamette)",
[2] = "Pentium 4 (Northwood)",
[4] = "Pentium 4 (Foster)",
[5] = "Pentium 4 (Foster)",
}
},
},
.legacy_cache_size = intel_size_cache,
#endif
.c_detect_tlb = intel_detect_tlb,
.c_early_init = early_init_intel,
.c_bsp_init = bsp_init_intel,
.c_init = init_intel,
.c_x86_vendor = X86_VENDOR_INTEL,
};
cpu_dev_register(intel_cpu_dev);
#undef pr_fmt
#define pr_fmt(fmt) "x86/split lock detection: " fmt
static const struct {
const char *option;
enum split_lock_detect_state state;
} sld_options[] __initconst = {
{ "off", sld_off },
{ "warn", sld_warn },
{ "fatal", sld_fatal },
};
static inline bool match_option(const char *arg, int arglen, const char *opt)
{
int len = strlen(opt);
return len == arglen && !strncmp(arg, opt, len);
}
static bool split_lock_verify_msr(bool on)
{
u64 ctrl, tmp;
if (rdmsrl_safe(MSR_TEST_CTRL, &ctrl))
return false;
if (on)
ctrl |= MSR_TEST_CTRL_SPLIT_LOCK_DETECT;
else
ctrl &= ~MSR_TEST_CTRL_SPLIT_LOCK_DETECT;
if (wrmsrl_safe(MSR_TEST_CTRL, ctrl))
return false;
rdmsrl(MSR_TEST_CTRL, tmp);
return ctrl == tmp;
}
static void __init split_lock_setup(void)
{
enum split_lock_detect_state state = sld_warn;
char arg[20];
int i, ret;
if (!split_lock_verify_msr(false)) {
pr_info("MSR access failed: Disabled\n");
return;
}
ret = cmdline_find_option(boot_command_line, "split_lock_detect",
arg, sizeof(arg));
if (ret >= 0) {
for (i = 0; i < ARRAY_SIZE(sld_options); i++) {
if (match_option(arg, ret, sld_options[i].option)) {
state = sld_options[i].state;
break;
}
}
}
switch (state) {
case sld_off:
pr_info("disabled\n");
return;
case sld_warn:
pr_info("warning about user-space split_locks\n");
break;
case sld_fatal:
pr_info("sending SIGBUS on user-space split_locks\n");
break;
}
rdmsrl(MSR_TEST_CTRL, msr_test_ctrl_cache);
if (!split_lock_verify_msr(true)) {
pr_info("MSR access failed: Disabled\n");
return;
}
sld_state = state;
setup_force_cpu_cap(X86_FEATURE_SPLIT_LOCK_DETECT);
}
/*
* MSR_TEST_CTRL is per core, but we treat it like a per CPU MSR. Locking
* is not implemented as one thread could undo the setting of the other
* thread immediately after dropping the lock anyway.
*/
static void sld_update_msr(bool on)
{
u64 test_ctrl_val = msr_test_ctrl_cache;
if (on)
test_ctrl_val |= MSR_TEST_CTRL_SPLIT_LOCK_DETECT;
wrmsrl(MSR_TEST_CTRL, test_ctrl_val);
}
static void split_lock_init(void)
{
if (cpu_model_supports_sld)
split_lock_verify_msr(sld_state != sld_off);
}
static void split_lock_warn(unsigned long ip)
{
pr_warn_ratelimited("#AC: %s/%d took a split_lock trap at address: 0x%lx\n",
current->comm, current->pid, ip);
/*
* Disable the split lock detection for this task so it can make
* progress and set TIF_SLD so the detection is re-enabled via
* switch_to_sld() when the task is scheduled out.
*/
sld_update_msr(false);
set_tsk_thread_flag(current, TIF_SLD);
}
bool handle_guest_split_lock(unsigned long ip)
{
if (sld_state == sld_warn) {
split_lock_warn(ip);
return true;
}
pr_warn_once("#AC: %s/%d %s split_lock trap at address: 0x%lx\n",
current->comm, current->pid,
sld_state == sld_fatal ? "fatal" : "bogus", ip);
current->thread.error_code = 0;
current->thread.trap_nr = X86_TRAP_AC;
force_sig_fault(SIGBUS, BUS_ADRALN, NULL);
return false;
}
EXPORT_SYMBOL_GPL(handle_guest_split_lock);
bool handle_user_split_lock(struct pt_regs *regs, long error_code)
{
if ((regs->flags & X86_EFLAGS_AC) || sld_state == sld_fatal)
return false;
split_lock_warn(regs->ip);
return true;
}
/*
* This function is called only when switching between tasks with
* different split-lock detection modes. It sets the MSR for the
* mode of the new task. This is right most of the time, but since
* the MSR is shared by hyperthreads on a physical core there can
* be glitches when the two threads need different modes.
*/
void switch_to_sld(unsigned long tifn)
{
sld_update_msr(!(tifn & _TIF_SLD));
}
/*
* Bits in the IA32_CORE_CAPABILITIES are not architectural, so they should
* only be trusted if it is confirmed that a CPU model implements a
* specific feature at a particular bit position.
*
* The possible driver data field values:
*
* - 0: CPU models that are known to have the per-core split-lock detection
* feature even though they do not enumerate IA32_CORE_CAPABILITIES.
*
* - 1: CPU models which may enumerate IA32_CORE_CAPABILITIES and if so use
* bit 5 to enumerate the per-core split-lock detection feature.
*/
static const struct x86_cpu_id split_lock_cpu_ids[] __initconst = {
X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X, 0),
X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_L, 0),
X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D, 0),
X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT, 1),
X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT_D, 1),
X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT_L, 1),
X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE_L, 1),
X86_MATCH_INTEL_FAM6_MODEL(TIGERLAKE, 1),
X86_MATCH_INTEL_FAM6_MODEL(SAPPHIRERAPIDS_X, 1),
X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE, 1),
{}
};
void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c)
{
const struct x86_cpu_id *m;
u64 ia32_core_caps;
if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
return;
m = x86_match_cpu(split_lock_cpu_ids);
if (!m)
return;
switch (m->driver_data) {
case 0:
break;
case 1:
if (!cpu_has(c, X86_FEATURE_CORE_CAPABILITIES))
return;
rdmsrl(MSR_IA32_CORE_CAPS, ia32_core_caps);
if (!(ia32_core_caps & MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT))
return;
break;
default:
return;
}
cpu_model_supports_sld = true;
split_lock_setup();
}
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