1 files changed, 446 insertions, 9 deletions

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index be82cd5841c3..2d7ea5480ec3 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -1,17 +1,21 @@
 // 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/pgtable.h>
 #include <asm/msr.h>
 #include <asm/bugs.h>
 #include <asm/cpu.h>
@@ -19,6 +23,12 @@
 #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>
+#include <asm/thermal.h>
 
 #ifdef CONFIG_X86_64
 #include <linux/topology.h>
@@ -31,6 +41,28 @@
 #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
@@ -62,7 +94,7 @@ static bool ring3mwait_disabled __read_mostly;
 static int __init ring3mwait_disable(char *__unused)
 {
 	ring3mwait_disabled = true;
-	return 0;
+	return 1;
 }
 __setup("ring3mwait=disable", ring3mwait_disable);
 
@@ -152,6 +184,38 @@ static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
 	return false;
 }
 
+int intel_cpu_collect_info(struct ucode_cpu_info *uci)
+{
+	unsigned int val[2];
+	unsigned int family, model;
+	struct cpu_signature csig = { 0 };
+	unsigned int eax, ebx, ecx, edx;
+
+	memset(uci, 0, sizeof(*uci));
+
+	eax = 0x00000001;
+	ecx = 0;
+	native_cpuid(&eax, &ebx, &ecx, &edx);
+	csig.sig = eax;
+
+	family = x86_family(eax);
+	model  = x86_model(eax);
+
+	if (model >= 5 || family > 6) {
+		/* get processor flags from MSR 0x17 */
+		native_rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
+		csig.pf = 1 << ((val[1] >> 18) & 7);
+	}
+
+	csig.rev = intel_get_microcode_revision();
+
+	uci->cpu_sig = csig;
+	uci->valid = 1;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(intel_cpu_collect_info);
+
 static void early_init_intel(struct cpuinfo_x86 *c)
 {
 	u64 misc_enable;
@@ -274,7 +338,7 @@ static void early_init_intel(struct cpuinfo_x86 *c)
 	 *  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
+	 * 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) {
@@ -305,6 +369,11 @@ static void early_init_intel(struct cpuinfo_x86 *c)
 		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
@@ -570,6 +639,9 @@ static void init_intel_misc_features(struct cpuinfo_x86 *c)
 	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);
@@ -610,9 +682,9 @@ static void init_intel(struct cpuinfo_x86 *c)
 		unsigned int l1, l2;
 
 		rdmsr(MSR_IA32_MISC_ENABLE, l1, l2);
-		if (!(l1 & (1<<11)))
+		if (!(l1 & MSR_IA32_MISC_ENABLE_BTS_UNAVAIL))
 			set_cpu_cap(c, X86_FEATURE_BTS);
-		if (!(l1 & (1<<12)))
+		if (!(l1 & MSR_IA32_MISC_ENABLE_PEBS_UNAVAIL))
 			set_cpu_cap(c, X86_FEATURE_PEBS);
 	}
 
@@ -680,10 +752,10 @@ static void init_intel(struct cpuinfo_x86 *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();
+	bus_lock_init();
+
+	intel_init_thermal(c);
 }
 
 #ifdef CONFIG_X86_32
@@ -940,8 +1012,373 @@ static const struct cpu_dev intel_cpu_dev = {
 #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 DEFINE_SEMAPHORE(buslock_sem);
+
+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(struct work_struct *work)
+{
+	sld_update_msr(true);
+	up(&buslock_sem);
+}
+
+/*
+ * 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 DECLARE_DELAYED_WORK(split_lock_reenable, __split_lock_reenable);
+
+static void split_lock_warn(unsigned long ip)
+{
+	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;
+
+	/* 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;
+	cpu = get_cpu();
+	schedule_delayed_work_on(cpu, &split_lock_reenable, 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;
+	}
+}
+
+/*
+ * 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),
+	X86_MATCH_INTEL_FAM6_MODEL(ALDERLAKE_L,		1),
+	X86_MATCH_INTEL_FAM6_MODEL(RAPTORLAKE,		1),
+	{}
+};
+
+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;
+
+	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();
+}
+
+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;
+}