1 files changed, 103 insertions, 45 deletions

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 8321c43554a1..2d7ea5480ec3 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -7,10 +7,13 @@
 #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>
@@ -91,7 +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);
 
@@ -181,6 +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;
@@ -647,9 +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);
 	}
 
@@ -717,13 +752,6 @@ static void init_intel(struct cpuinfo_x86 *c)
 
 	init_intel_misc_features(c);
 
-	if (tsx_ctrl_state == TSX_CTRL_ENABLE)
-		tsx_enable();
-	else if (tsx_ctrl_state == TSX_CTRL_DISABLE)
-		tsx_disable();
-	else if (tsx_ctrl_state == TSX_CTRL_RTM_ALWAYS_ABORT)
-		tsx_clear_cpuid();
-
 	split_lock_init();
 	bus_lock_init();
 
@@ -1006,6 +1034,8 @@ static const struct {
 
 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;
@@ -1116,18 +1146,52 @@ static void split_lock_init(void)
 		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)
 {
-	pr_warn_ratelimited("#AC: %s/%d took a split_lock trap at address: 0x%lx\n",
-			    current->comm, current->pid, ip);
+	int cpu;
 
-	/*
-	 * 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.
-	 */
+	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);
-	set_tsk_thread_flag(current, TIF_SLD);
+	put_cpu();
 }
 
 bool handle_guest_split_lock(unsigned long ip)
@@ -1152,22 +1216,23 @@ static void bus_lock_init(void)
 {
 	u64 val;
 
-	/*
-	 * Warn and fatal are handled by #AC for split lock if #AC for
-	 * split lock is supported.
-	 */
-	if (!boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT) ||
-	    (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT) &&
-	    (sld_state == sld_warn || sld_state == sld_fatal)) ||
-	    sld_state == sld_off)
+	if (!boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT))
 		return;
 
-	/*
-	 * Enable #DB for bus lock. All bus locks are handled in #DB except
-	 * split locks are handled in #AC in the fatal case.
-	 */
 	rdmsrl(MSR_IA32_DEBUGCTLMSR, val);
-	val |= DEBUGCTLMSR_BUS_LOCK_DETECT;
+
+	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);
 }
 
@@ -1201,18 +1266,6 @@ void handle_bus_lock(struct pt_regs *regs)
 }
 
 /*
- * 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.
@@ -1237,6 +1290,7 @@ static const struct x86_cpu_id split_lock_cpu_ids[] __initconst = {
 	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),
 	{}
 };
 
@@ -1281,10 +1335,14 @@ static void sld_state_show(void)
 		pr_info("disabled\n");
 		break;
 	case sld_warn:
-		if (boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT))
+		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");
-		else if (boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT))
+			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)) {