1 files changed, 213 insertions, 111 deletions

diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 921d9d7df400..5ed5095320e6 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -12,42 +12,63 @@
 #include <linux/clockchips.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
+#include <linux/kexec.h>
+#include <linux/kgdb.h>
+#include <linux/percpu.h>
 #include <linux/profile.h>
 #include <linux/smp.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/delay.h>
+#include <linux/irq.h>
 #include <linux/irq_work.h>
+#include <linux/nmi.h>
 
-#include <asm/sbi.h>
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>
+#include <asm/cpu_ops.h>
 
 enum ipi_message_type {
 	IPI_RESCHEDULE,
 	IPI_CALL_FUNC,
 	IPI_CPU_STOP,
+	IPI_CPU_CRASH_STOP,
 	IPI_IRQ_WORK,
 	IPI_TIMER,
+	IPI_CPU_BACKTRACE,
+	IPI_KGDB_ROUNDUP,
 	IPI_MAX
 };
 
+static const char * const ipi_names[] = {
+	[IPI_RESCHEDULE]	= "Rescheduling interrupts",
+	[IPI_CALL_FUNC]		= "Function call interrupts",
+	[IPI_CPU_STOP]		= "CPU stop interrupts",
+	[IPI_CPU_CRASH_STOP]	= "CPU stop (for crash dump) interrupts",
+	[IPI_IRQ_WORK]		= "IRQ work interrupts",
+	[IPI_TIMER]		= "Timer broadcast interrupts",
+	[IPI_CPU_BACKTRACE]     = "CPU backtrace interrupts",
+	[IPI_KGDB_ROUNDUP]	= "KGDB roundup interrupts",
+};
+
 unsigned long __cpuid_to_hartid_map[NR_CPUS] __ro_after_init = {
 	[0 ... NR_CPUS-1] = INVALID_HARTID
 };
+EXPORT_SYMBOL_GPL(__cpuid_to_hartid_map);
 
 void __init smp_setup_processor_id(void)
 {
 	cpuid_to_hartid_map(0) = boot_cpu_hartid;
+
+	pr_info("Booting Linux on hartid %lu\n", boot_cpu_hartid);
 }
 
-/* A collection of single bit ipi messages.  */
-static struct {
-	unsigned long stats[IPI_MAX] ____cacheline_aligned;
-	unsigned long bits ____cacheline_aligned;
-} ipi_data[NR_CPUS] __cacheline_aligned;
+static DEFINE_PER_CPU_READ_MOSTLY(int, ipi_dummy_dev);
+static int ipi_virq_base __ro_after_init;
+static int nr_ipi __ro_after_init = IPI_MAX;
+static struct irq_desc *ipi_desc[IPI_MAX] __read_mostly;
 
-int riscv_hartid_to_cpuid(int hartid)
+int riscv_hartid_to_cpuid(unsigned long hartid)
 {
 	int i;
 
@@ -55,31 +76,9 @@ int riscv_hartid_to_cpuid(int hartid)
 		if (cpuid_to_hartid_map(i) == hartid)
 			return i;
 
-	pr_err("Couldn't find cpu id for hartid [%d]\n", hartid);
 	return -ENOENT;
 }
 
-void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out)
-{
-	int cpu;
-
-	cpumask_clear(out);
-	for_each_cpu(cpu, in)
-		cpumask_set_cpu(cpuid_to_hartid_map(cpu), out);
-}
-EXPORT_SYMBOL_GPL(riscv_cpuid_to_hartid_mask);
-
-bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
-{
-	return phys_id == cpuid_to_hartid_map(cpu);
-}
-
-/* Unsupported */
-int setup_profiling_timer(unsigned int multiplier)
-{
-	return -EINVAL;
-}
-
 static void ipi_stop(void)
 {
 	set_cpu_online(smp_processor_id(), false);
@@ -87,48 +86,40 @@ static void ipi_stop(void)
 		wait_for_interrupt();
 }
 
-static const struct riscv_ipi_ops *ipi_ops __ro_after_init;
+#ifdef CONFIG_KEXEC_CORE
+static atomic_t waiting_for_crash_ipi = ATOMIC_INIT(0);
 
-void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops)
+static inline void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
 {
-	ipi_ops = ops;
-}
-EXPORT_SYMBOL_GPL(riscv_set_ipi_ops);
+	crash_save_cpu(regs, cpu);
 
-void riscv_clear_ipi(void)
-{
-	if (ipi_ops && ipi_ops->ipi_clear)
-		ipi_ops->ipi_clear();
+	atomic_dec(&waiting_for_crash_ipi);
+
+	local_irq_disable();
+
+#ifdef CONFIG_HOTPLUG_CPU
+	if (cpu_has_hotplug(cpu))
+		cpu_ops->cpu_stop();
+#endif
 
-	csr_clear(CSR_IP, IE_SIE);
+	for(;;)
+		wait_for_interrupt();
+}
+#else
+static inline void ipi_cpu_crash_stop(unsigned int cpu, struct pt_regs *regs)
+{
+	unreachable();
 }
-EXPORT_SYMBOL_GPL(riscv_clear_ipi);
+#endif
 
 static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
 {
-	int cpu;
-
-	smp_mb__before_atomic();
-	for_each_cpu(cpu, mask)
-		set_bit(op, &ipi_data[cpu].bits);
-	smp_mb__after_atomic();
-
-	if (ipi_ops && ipi_ops->ipi_inject)
-		ipi_ops->ipi_inject(mask);
-	else
-		pr_warn("SMP: IPI inject method not available\n");
+	__ipi_send_mask(ipi_desc[op], mask);
 }
 
 static void send_ipi_single(int cpu, enum ipi_message_type op)
 {
-	smp_mb__before_atomic();
-	set_bit(op, &ipi_data[cpu].bits);
-	smp_mb__after_atomic();
-
-	if (ipi_ops && ipi_ops->ipi_inject)
-		ipi_ops->ipi_inject(cpumask_of(cpu));
-	else
-		pr_warn("SMP: IPI inject method not available\n");
+	__ipi_send_mask(ipi_desc[op], cpumask_of(cpu));
 }
 
 #ifdef CONFIG_IRQ_WORK
@@ -138,71 +129,98 @@ void arch_irq_work_raise(void)
 }
 #endif
 
-void handle_IPI(struct pt_regs *regs)
+static irqreturn_t handle_IPI(int irq, void *data)
+{
+	unsigned int cpu = smp_processor_id();
+	int ipi = irq - ipi_virq_base;
+
+	switch (ipi) {
+	case IPI_RESCHEDULE:
+		scheduler_ipi();
+		break;
+	case IPI_CALL_FUNC:
+		generic_smp_call_function_interrupt();
+		break;
+	case IPI_CPU_STOP:
+		ipi_stop();
+		break;
+	case IPI_CPU_CRASH_STOP:
+		ipi_cpu_crash_stop(cpu, get_irq_regs());
+		break;
+	case IPI_IRQ_WORK:
+		irq_work_run();
+		break;
+#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
+	case IPI_TIMER:
+		tick_receive_broadcast();
+		break;
+#endif
+	case IPI_CPU_BACKTRACE:
+		nmi_cpu_backtrace(get_irq_regs());
+		break;
+	case IPI_KGDB_ROUNDUP:
+		kgdb_nmicallback(cpu, get_irq_regs());
+		break;
+	default:
+		pr_warn("CPU%d: unhandled IPI%d\n", cpu, ipi);
+		break;
+	}
+
+	return IRQ_HANDLED;
+}
+
+void riscv_ipi_enable(void)
 {
-	struct pt_regs *old_regs = set_irq_regs(regs);
-	unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
-	unsigned long *stats = ipi_data[smp_processor_id()].stats;
+	int i;
 
-	irq_enter();
+	if (WARN_ON_ONCE(!ipi_virq_base))
+		return;
 
-	riscv_clear_ipi();
+	for (i = 0; i < nr_ipi; i++)
+		enable_percpu_irq(ipi_virq_base + i, 0);
+}
 
-	while (true) {
-		unsigned long ops;
+void riscv_ipi_disable(void)
+{
+	int i;
 
-		/* Order bit clearing and data access. */
-		mb();
+	if (WARN_ON_ONCE(!ipi_virq_base))
+		return;
 
-		ops = xchg(pending_ipis, 0);
-		if (ops == 0)
-			goto done;
+	for (i = 0; i < nr_ipi; i++)
+		disable_percpu_irq(ipi_virq_base + i);
+}
 
-		if (ops & (1 << IPI_RESCHEDULE)) {
-			stats[IPI_RESCHEDULE]++;
-			scheduler_ipi();
-		}
+bool riscv_ipi_have_virq_range(void)
+{
+	return (ipi_virq_base) ? true : false;
+}
 
-		if (ops & (1 << IPI_CALL_FUNC)) {
-			stats[IPI_CALL_FUNC]++;
-			generic_smp_call_function_interrupt();
-		}
+void riscv_ipi_set_virq_range(int virq, int nr)
+{
+	int i, err;
 
-		if (ops & (1 << IPI_CPU_STOP)) {
-			stats[IPI_CPU_STOP]++;
-			ipi_stop();
-		}
+	if (WARN_ON(ipi_virq_base))
+		return;
 
-		if (ops & (1 << IPI_IRQ_WORK)) {
-			stats[IPI_IRQ_WORK]++;
-			irq_work_run();
-		}
+	WARN_ON(nr < IPI_MAX);
+	nr_ipi = min(nr, IPI_MAX);
+	ipi_virq_base = virq;
 
-#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
-		if (ops & (1 << IPI_TIMER)) {
-			stats[IPI_TIMER]++;
-			tick_receive_broadcast();
-		}
-#endif
-		BUG_ON((ops >> IPI_MAX) != 0);
+	/* Request IPIs */
+	for (i = 0; i < nr_ipi; i++) {
+		err = request_percpu_irq(ipi_virq_base + i, handle_IPI,
+					 ipi_names[i], &ipi_dummy_dev);
+		WARN_ON(err);
 
-		/* Order data access and bit testing. */
-		mb();
+		ipi_desc[i] = irq_to_desc(ipi_virq_base + i);
+		irq_set_status_flags(ipi_virq_base + i, IRQ_HIDDEN);
 	}
 
-done:
-	irq_exit();
-	set_irq_regs(old_regs);
+	/* Enabled IPIs for boot CPU immediately */
+	riscv_ipi_enable();
 }
 
-static const char * const ipi_names[] = {
-	[IPI_RESCHEDULE]	= "Rescheduling interrupts",
-	[IPI_CALL_FUNC]		= "Function call interrupts",
-	[IPI_CPU_STOP]		= "CPU stop interrupts",
-	[IPI_IRQ_WORK]		= "IRQ work interrupts",
-	[IPI_TIMER]		= "Timer broadcast interrupts",
-};
-
 void show_ipi_stats(struct seq_file *p, int prec)
 {
 	unsigned int cpu, i;
@@ -211,7 +229,7 @@ void show_ipi_stats(struct seq_file *p, int prec)
 		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
 			   prec >= 4 ? " " : "");
 		for_each_online_cpu(cpu)
-			seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]);
+			seq_printf(p, "%10u ", irq_desc_kstat_cpu(ipi_desc[i], cpu));
 		seq_printf(p, " %s\n", ipi_names[i]);
 	}
 }
@@ -258,8 +276,92 @@ void smp_send_stop(void)
 			   cpumask_pr_args(cpu_online_mask));
 }
 
-void smp_send_reschedule(int cpu)
+#ifdef CONFIG_KEXEC_CORE
+/*
+ * The number of CPUs online, not counting this CPU (which may not be
+ * fully online and so not counted in num_online_cpus()).
+ */
+static inline unsigned int num_other_online_cpus(void)
+{
+	unsigned int this_cpu_online = cpu_online(smp_processor_id());
+
+	return num_online_cpus() - this_cpu_online;
+}
+
+void crash_smp_send_stop(void)
+{
+	static int cpus_stopped;
+	cpumask_t mask;
+	unsigned long timeout;
+
+	/*
+	 * This function can be called twice in panic path, but obviously
+	 * we execute this only once.
+	 */
+	if (cpus_stopped)
+		return;
+
+	cpus_stopped = 1;
+
+	/*
+	 * If this cpu is the only one alive at this point in time, online or
+	 * not, there are no stop messages to be sent around, so just back out.
+	 */
+	if (num_other_online_cpus() == 0)
+		return;
+
+	cpumask_copy(&mask, cpu_online_mask);
+	cpumask_clear_cpu(smp_processor_id(), &mask);
+
+	atomic_set(&waiting_for_crash_ipi, num_other_online_cpus());
+
+	pr_crit("SMP: stopping secondary CPUs\n");
+	send_ipi_mask(&mask, IPI_CPU_CRASH_STOP);
+
+	/* Wait up to one second for other CPUs to stop */
+	timeout = USEC_PER_SEC;
+	while ((atomic_read(&waiting_for_crash_ipi) > 0) && timeout--)
+		udelay(1);
+
+	if (atomic_read(&waiting_for_crash_ipi) > 0)
+		pr_warn("SMP: failed to stop secondary CPUs %*pbl\n",
+			cpumask_pr_args(&mask));
+}
+
+bool smp_crash_stop_failed(void)
+{
+	return (atomic_read(&waiting_for_crash_ipi) > 0);
+}
+#endif
+
+void arch_smp_send_reschedule(int cpu)
 {
 	send_ipi_single(cpu, IPI_RESCHEDULE);
 }
-EXPORT_SYMBOL_GPL(smp_send_reschedule);
+EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
+
+static void riscv_backtrace_ipi(cpumask_t *mask)
+{
+	send_ipi_mask(mask, IPI_CPU_BACKTRACE);
+}
+
+void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu)
+{
+	nmi_trigger_cpumask_backtrace(mask, exclude_cpu, riscv_backtrace_ipi);
+}
+
+#ifdef CONFIG_KGDB
+void kgdb_roundup_cpus(void)
+{
+	int this_cpu = raw_smp_processor_id();
+	int cpu;
+
+	for_each_online_cpu(cpu) {
+		/* No need to roundup ourselves */
+		if (cpu == this_cpu)
+			continue;
+
+		send_ipi_single(cpu, IPI_KGDB_ROUNDUP);
+	}
+}
+#endif