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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:27:49 +0000
commitace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch)
treeb2d64bc10158fdd5497876388cd68142ca374ed3 /arch/x86/kernel/cpu/intel.c
parentInitial commit. (diff)
downloadlinux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz
linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/kernel/cpu/intel.c')
-rw-r--r--arch/x86/kernel/cpu/intel.c1380
1 files changed, 1380 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
new file mode 100644
index 0000000000..be4045628f
--- /dev/null
+++ b/arch/x86/kernel/cpu/intel.c
@@ -0,0 +1,1380 @@
+// 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/semaphore.h>
+#include <linux/thread_info.h>
+#include <linux/init.h>
+#include <linux/uaccess.h>
+#include <linux/workqueue.h>
+#include <linux/delay.h>
+#include <linux/cpuhotplug.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.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>
+#include <asm/thermal.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,
+ sld_ratelimit,
+};
+
+/*
+ * Default to sld_off because most systems do not support split lock detection.
+ * sld_state_setup() will switch this to sld_warn on systems that support
+ * split lock/bus 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 1;
+}
+__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 instead 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 bus_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 & MSR_IA32_MISC_ENABLE_BTS_UNAVAIL))
+ set_cpu_cap(c, X86_FEATURE_BTS);
+ if (!(l1 & MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL))
+ 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);
+
+ split_lock_init();
+ bus_lock_init();
+
+ intel_init_thermal(c);
+}
+
+#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 },
+ { "ratelimit:", sld_ratelimit },
+};
+
+static struct ratelimit_state bld_ratelimit;
+
+static unsigned int sysctl_sld_mitigate = 1;
+static DEFINE_SEMAPHORE(buslock_sem, 1);
+
+#ifdef CONFIG_PROC_SYSCTL
+static struct ctl_table sld_sysctls[] = {
+ {
+ .procname = "split_lock_mitigate",
+ .data = &sysctl_sld_mitigate,
+ .maxlen = sizeof(unsigned int),
+ .mode = 0644,
+ .proc_handler = proc_douintvec_minmax,
+ .extra1 = SYSCTL_ZERO,
+ .extra2 = SYSCTL_ONE,
+ },
+ {}
+};
+
+static int __init sld_mitigate_sysctl_init(void)
+{
+ register_sysctl_init("kernel", sld_sysctls);
+ return 0;
+}
+
+late_initcall(sld_mitigate_sysctl_init);
+#endif
+
+static inline bool match_option(const char *arg, int arglen, const char *opt)
+{
+ int len = strlen(opt), ratelimit;
+
+ if (strncmp(arg, opt, len))
+ return false;
+
+ /*
+ * Min ratelimit is 1 bus lock/sec.
+ * Max ratelimit is 1000 bus locks/sec.
+ */
+ if (sscanf(arg, "ratelimit:%d", &ratelimit) == 1 &&
+ ratelimit > 0 && ratelimit <= 1000) {
+ ratelimit_state_init(&bld_ratelimit, HZ, ratelimit);
+ ratelimit_set_flags(&bld_ratelimit, RATELIMIT_MSG_ON_RELEASE);
+ return true;
+ }
+
+ return len == arglen;
+}
+
+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 sld_state_setup(void)
+{
+ enum split_lock_detect_state state = sld_warn;
+ char arg[20];
+ int i, ret;
+
+ if (!boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT) &&
+ !boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT))
+ 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;
+ }
+ }
+ }
+ sld_state = state;
+}
+
+static void __init __split_lock_setup(void)
+{
+ if (!split_lock_verify_msr(false)) {
+ pr_info("MSR access failed: Disabled\n");
+ return;
+ }
+
+ rdmsrl(MSR_TEST_CTRL, msr_test_ctrl_cache);
+
+ if (!split_lock_verify_msr(true)) {
+ pr_info("MSR access failed: Disabled\n");
+ return;
+ }
+
+ /* Restore the MSR to its cached value. */
+ wrmsrl(MSR_TEST_CTRL, msr_test_ctrl_cache);
+
+ 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)
+{
+ /*
+ * #DB for bus lock handles ratelimit and #AC for split lock is
+ * disabled.
+ */
+ if (sld_state == sld_ratelimit) {
+ split_lock_verify_msr(false);
+ return;
+ }
+
+ if (cpu_model_supports_sld)
+ split_lock_verify_msr(sld_state != sld_off);
+}
+
+static void __split_lock_reenable_unlock(struct work_struct *work)
+{
+ sld_update_msr(true);
+ up(&buslock_sem);
+}
+
+static DECLARE_DELAYED_WORK(sl_reenable_unlock, __split_lock_reenable_unlock);
+
+static void __split_lock_reenable(struct work_struct *work)
+{
+ sld_update_msr(true);
+}
+static DECLARE_DELAYED_WORK(sl_reenable, __split_lock_reenable);
+
+/*
+ * If a CPU goes offline with pending delayed work to re-enable split lock
+ * detection then the delayed work will be executed on some other CPU. That
+ * handles releasing the buslock_sem, but because it executes on a
+ * different CPU probably won't re-enable split lock detection. This is a
+ * problem on HT systems since the sibling CPU on the same core may then be
+ * left running with split lock detection disabled.
+ *
+ * Unconditionally re-enable detection here.
+ */
+static int splitlock_cpu_offline(unsigned int cpu)
+{
+ sld_update_msr(true);
+
+ return 0;
+}
+
+static void split_lock_warn(unsigned long ip)
+{
+ struct delayed_work *work;
+ int cpu;
+
+ if (!current->reported_split_lock)
+ pr_warn_ratelimited("#AC: %s/%d took a split_lock trap at address: 0x%lx\n",
+ current->comm, current->pid, ip);
+ current->reported_split_lock = 1;
+
+ if (sysctl_sld_mitigate) {
+ /*
+ * misery factor #1:
+ * sleep 10ms before trying to execute split lock.
+ */
+ if (msleep_interruptible(10) > 0)
+ return;
+ /*
+ * Misery factor #2:
+ * only allow one buslocked disabled core at a time.
+ */
+ if (down_interruptible(&buslock_sem) == -EINTR)
+ return;
+ work = &sl_reenable_unlock;
+ } else {
+ work = &sl_reenable;
+ }
+
+ cpu = get_cpu();
+ schedule_delayed_work_on(cpu, work, 2);
+
+ /* Disable split lock detection on this CPU to make progress */
+ sld_update_msr(false);
+ put_cpu();
+}
+
+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);
+
+static void bus_lock_init(void)
+{
+ u64 val;
+
+ if (!boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT))
+ return;
+
+ rdmsrl(MSR_IA32_DEBUGCTLMSR, val);
+
+ if ((boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT) &&
+ (sld_state == sld_warn || sld_state == sld_fatal)) ||
+ sld_state == sld_off) {
+ /*
+ * Warn and fatal are handled by #AC for split lock if #AC for
+ * split lock is supported.
+ */
+ val &= ~DEBUGCTLMSR_BUS_LOCK_DETECT;
+ } else {
+ val |= DEBUGCTLMSR_BUS_LOCK_DETECT;
+ }
+
+ wrmsrl(MSR_IA32_DEBUGCTLMSR, val);
+}
+
+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;
+}
+
+void handle_bus_lock(struct pt_regs *regs)
+{
+ switch (sld_state) {
+ case sld_off:
+ break;
+ case sld_ratelimit:
+ /* Enforce no more than bld_ratelimit bus locks/sec. */
+ while (!__ratelimit(&bld_ratelimit))
+ msleep(20);
+ /* Warn on the bus lock. */
+ fallthrough;
+ case sld_warn:
+ pr_warn_ratelimited("#DB: %s/%d took a bus_lock trap at address: 0x%lx\n",
+ current->comm, current->pid, regs->ip);
+ break;
+ case sld_fatal:
+ force_sig_fault(SIGBUS, BUS_ADRALN, NULL);
+ break;
+ }
+}
+
+/*
+ * CPU models that are known to have the per-core split-lock detection
+ * feature even though they do not enumerate IA32_CORE_CAPABILITIES.
+ */
+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),
+ {}
+};
+
+static void __init split_lock_setup(struct cpuinfo_x86 *c)
+{
+ const struct x86_cpu_id *m;
+ u64 ia32_core_caps;
+
+ if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+ return;
+
+ /* Check for CPUs that have support but do not enumerate it: */
+ m = x86_match_cpu(split_lock_cpu_ids);
+ if (m)
+ goto supported;
+
+ if (!cpu_has(c, X86_FEATURE_CORE_CAPABILITIES))
+ return;
+
+ /*
+ * Not all bits in MSR_IA32_CORE_CAPS are architectural, but
+ * MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT is. All CPUs that set
+ * it have split lock detection.
+ */
+ rdmsrl(MSR_IA32_CORE_CAPS, ia32_core_caps);
+ if (ia32_core_caps & MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT)
+ goto supported;
+
+ /* CPU is not in the model list and does not have the MSR bit: */
+ return;
+
+supported:
+ cpu_model_supports_sld = true;
+ __split_lock_setup();
+}
+
+static void sld_state_show(void)
+{
+ if (!boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT) &&
+ !boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT))
+ return;
+
+ switch (sld_state) {
+ case sld_off:
+ pr_info("disabled\n");
+ break;
+ case sld_warn:
+ if (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) {
+ pr_info("#AC: crashing the kernel on kernel split_locks and warning on user-space split_locks\n");
+ if (cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
+ "x86/splitlock", NULL, splitlock_cpu_offline) < 0)
+ pr_warn("No splitlock CPU offline handler\n");
+ } else if (boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT)) {
+ pr_info("#DB: warning on user-space bus_locks\n");
+ }
+ break;
+ case sld_fatal:
+ if (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)) {
+ pr_info("#AC: crashing the kernel on kernel split_locks and sending SIGBUS on user-space split_locks\n");
+ } else if (boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT)) {
+ pr_info("#DB: sending SIGBUS on user-space bus_locks%s\n",
+ boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT) ?
+ " from non-WB" : "");
+ }
+ break;
+ case sld_ratelimit:
+ if (boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT))
+ pr_info("#DB: setting system wide bus lock rate limit to %u/sec\n", bld_ratelimit.burst);
+ break;
+ }
+}
+
+void __init sld_setup(struct cpuinfo_x86 *c)
+{
+ split_lock_setup(c);
+ sld_state_setup();
+ sld_state_show();
+}
+
+#define X86_HYBRID_CPU_TYPE_ID_SHIFT 24
+
+/**
+ * get_this_hybrid_cpu_type() - Get the type of this hybrid CPU
+ *
+ * Returns the CPU type [31:24] (i.e., Atom or Core) of a CPU in
+ * a hybrid processor. If the processor is not hybrid, returns 0.
+ */
+u8 get_this_hybrid_cpu_type(void)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_HYBRID_CPU))
+ return 0;
+
+ return cpuid_eax(0x0000001a) >> X86_HYBRID_CPU_TYPE_ID_SHIFT;
+}