1 files changed, 109 insertions, 105 deletions

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 78db90dcc91..a5aeefab03c 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -39,6 +39,7 @@
 #include <asm/atomic.h>
 #include <asm/cacheflush.h>
 #include <asm/cputype.h>
+#include <asm/cpu_ops.h>
 #include <asm/mmu_context.h>
 #include <asm/pgtable.h>
 #include <asm/pgalloc.h>
@@ -54,7 +55,6 @@
  * where to place its SVC stack
  */
 struct secondary_data secondary_data;
-volatile unsigned long secondary_holding_pen_release = INVALID_HWID;
 
 enum ipi_msg_type {
 	IPI_RESCHEDULE,
@@ -63,61 +63,16 @@ enum ipi_msg_type {
 	IPI_CPU_STOP,
 };
 
-static DEFINE_RAW_SPINLOCK(boot_lock);
-
-/*
- * Write secondary_holding_pen_release in a way that is guaranteed to be
- * visible to all observers, irrespective of whether they're taking part
- * in coherency or not.  This is necessary for the hotplug code to work
- * reliably.
- */
-static void write_pen_release(u64 val)
-{
-	void *start = (void *)&secondary_holding_pen_release;
-	unsigned long size = sizeof(secondary_holding_pen_release);
-
-	secondary_holding_pen_release = val;
-	__flush_dcache_area(start, size);
-}
-
 /*
  * Boot a secondary CPU, and assign it the specified idle task.
  * This also gives us the initial stack to use for this CPU.
  */
 static int boot_secondary(unsigned int cpu, struct task_struct *idle)
 {
-	unsigned long timeout;
-
-	/*
-	 * Set synchronisation state between this boot processor
-	 * and the secondary one
-	 */
-	raw_spin_lock(&boot_lock);
-
-	/*
-	 * Update the pen release flag.
-	 */
-	write_pen_release(cpu_logical_map(cpu));
-
-	/*
-	 * Send an event, causing the secondaries to read pen_release.
-	 */
-	sev();
-
-	timeout = jiffies + (1 * HZ);
-	while (time_before(jiffies, timeout)) {
-		if (secondary_holding_pen_release == INVALID_HWID)
-			break;
-		udelay(10);
-	}
-
-	/*
-	 * Now the secondary core is starting up let it run its
-	 * calibrations, then wait for it to finish
-	 */
-	raw_spin_unlock(&boot_lock);
+	if (cpu_ops[cpu]->cpu_boot)
+		return cpu_ops[cpu]->cpu_boot(cpu);
 
-	return secondary_holding_pen_release != INVALID_HWID ? -ENOSYS : 0;
+	return -EOPNOTSUPP;
 }
 
 static DECLARE_COMPLETION(cpu_running);
@@ -187,17 +142,13 @@ asmlinkage void secondary_start_kernel(void)
 	preempt_disable();
 	trace_hardirqs_off();
 
-	/*
-	 * Let the primary processor know we're out of the
-	 * pen, then head off into the C entry point
-	 */
-	write_pen_release(INVALID_HWID);
+	if (cpu_ops[cpu]->cpu_postboot)
+		cpu_ops[cpu]->cpu_postboot();
 
 	/*
-	 * Synchronise with the boot thread.
+	 * Enable GIC and timers.
 	 */
-	raw_spin_lock(&boot_lock);
-	raw_spin_unlock(&boot_lock);
+	notify_cpu_starting(cpu);
 
 	/*
 	 * OK, now it's safe to let the boot CPU continue.  Wait for
@@ -207,11 +158,6 @@ asmlinkage void secondary_start_kernel(void)
 	set_cpu_online(cpu, true);
 	complete(&cpu_running);
 
-	/*
-	 * Enable GIC and timers.
-	 */
-	notify_cpu_starting(cpu);
-
 	local_irq_enable();
 	local_fiq_enable();
 
@@ -221,39 +167,113 @@ asmlinkage void secondary_start_kernel(void)
 	cpu_startup_entry(CPUHP_ONLINE);
 }
 
-void __init smp_cpus_done(unsigned int max_cpus)
+#ifdef CONFIG_HOTPLUG_CPU
+static int op_cpu_disable(unsigned int cpu)
 {
-	pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
+	/*
+	 * If we don't have a cpu_die method, abort before we reach the point
+	 * of no return. CPU0 may not have an cpu_ops, so test for it.
+	 */
+	if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_die)
+		return -EOPNOTSUPP;
+
+	/*
+	 * We may need to abort a hot unplug for some other mechanism-specific
+	 * reason.
+	 */
+	if (cpu_ops[cpu]->cpu_disable)
+		return cpu_ops[cpu]->cpu_disable(cpu);
+
+	return 0;
 }
 
-void __init smp_prepare_boot_cpu(void)
+/*
+ * __cpu_disable runs on the processor to be shutdown.
+ */
+int __cpu_disable(void)
 {
-}
+	unsigned int cpu = smp_processor_id();
+	int ret;
 
-static void (*smp_cross_call)(const struct cpumask *, unsigned int);
+	ret = op_cpu_disable(cpu);
+	if (ret)
+		return ret;
 
-static const struct smp_enable_ops *enable_ops[] __initconst = {
-	&smp_spin_table_ops,
-	&smp_psci_ops,
-	NULL,
-};
+	/*
+	 * Take this CPU offline.  Once we clear this, we can't return,
+	 * and we must not schedule until we're ready to give up the cpu.
+	 */
+	set_cpu_online(cpu, false);
+
+	/*
+	 * OK - migrate IRQs away from this CPU
+	 */
+	migrate_irqs();
 
-static const struct smp_enable_ops *smp_enable_ops[NR_CPUS];
+	/*
+	 * Remove this CPU from the vm mask set of all processes.
+	 */
+	clear_tasks_mm_cpumask(cpu);
 
-static const struct smp_enable_ops * __init smp_get_enable_ops(const char *name)
-{
-	const struct smp_enable_ops **ops = enable_ops;
+	return 0;
+}
 
-	while (*ops) {
-		if (!strcmp(name, (*ops)->name))
-			return *ops;
+static DECLARE_COMPLETION(cpu_died);
 
-		ops++;
+/*
+ * called on the thread which is asking for a CPU to be shutdown -
+ * waits until shutdown has completed, or it is timed out.
+ */
+void __cpu_die(unsigned int cpu)
+{
+	if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) {
+		pr_crit("CPU%u: cpu didn't die\n", cpu);
+		return;
 	}
+	pr_notice("CPU%u: shutdown\n", cpu);
+}
+
+/*
+ * Called from the idle thread for the CPU which has been shutdown.
+ *
+ * Note that we disable IRQs here, but do not re-enable them
+ * before returning to the caller. This is also the behaviour
+ * of the other hotplug-cpu capable cores, so presumably coming
+ * out of idle fixes this.
+ */
+void cpu_die(void)
+{
+	unsigned int cpu = smp_processor_id();
+
+	idle_task_exit();
 
-	return NULL;
+	local_irq_disable();
+
+	/* Tell __cpu_die() that this CPU is now safe to dispose of */
+	complete(&cpu_died);
+
+	/*
+	 * Actually shutdown the CPU. This must never fail. The specific hotplug
+	 * mechanism must perform all required cache maintenance to ensure that
+	 * no dirty lines are lost in the process of shutting down the CPU.
+	 */
+	cpu_ops[cpu]->cpu_die(cpu);
+
+	BUG();
+}
+#endif
+
+void __init smp_cpus_done(unsigned int max_cpus)
+{
+	pr_info("SMP: Total of %d processors activated.\n", num_online_cpus());
 }
 
+void __init smp_prepare_boot_cpu(void)
+{
+}
+
+static void (*smp_cross_call)(const struct cpumask *, unsigned int);
+
 /*
  * Enumerate the possible CPU set from the device tree and build the
  * cpu logical map array containing MPIDR values related to logical
@@ -261,9 +281,8 @@ static const struct smp_enable_ops * __init smp_get_enable_ops(const char *name)
  */
 void __init smp_init_cpus(void)
 {
-	const char *enable_method;
 	struct device_node *dn = NULL;
-	int i, cpu = 1;
+	unsigned int i, cpu = 1;
 	bool bootcpu_valid = false;
 
 	while ((dn = of_find_node_by_type(dn, "cpu"))) {
@@ -332,25 +351,10 @@ void __init smp_init_cpus(void)
 		if (cpu >= NR_CPUS)
 			goto next;
 
-		/*
-		 * We currently support only the "spin-table" enable-method.
-		 */
-		enable_method = of_get_property(dn, "enable-method", NULL);
-		if (!enable_method) {
-			pr_err("%s: missing enable-method property\n",
-				dn->full_name);
+		if (cpu_read_ops(dn, cpu) != 0)
 			goto next;
-		}
-
-		smp_enable_ops[cpu] = smp_get_enable_ops(enable_method);
-
-		if (!smp_enable_ops[cpu]) {
-			pr_err("%s: invalid enable-method property: %s\n",
-			       dn->full_name, enable_method);
-			goto next;
-		}
 
-		if (smp_enable_ops[cpu]->init_cpu(dn, cpu))
+		if (cpu_ops[cpu]->cpu_init(dn, cpu))
 			goto next;
 
 		pr_debug("cpu logical map 0x%llx\n", hwid);
@@ -380,8 +384,8 @@ next:
 
 void __init smp_prepare_cpus(unsigned int max_cpus)
 {
-	int cpu, err;
-	unsigned int ncores = num_possible_cpus();
+	int err;
+	unsigned int cpu, ncores = num_possible_cpus();
 
 	/*
 	 * are we trying to boot more cores than exist?
@@ -408,10 +412,10 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 		if (cpu == smp_processor_id())
 			continue;
 
-		if (!smp_enable_ops[cpu])
+		if (!cpu_ops[cpu])
 			continue;
 
-		err = smp_enable_ops[cpu]->prepare_cpu(cpu);
+		err = cpu_ops[cpu]->cpu_prepare(cpu);
 		if (err)
 			continue;
 
@@ -451,7 +455,7 @@ void show_ipi_list(struct seq_file *p, int prec)
 	for (i = 0; i < NR_IPI; i++) {
 		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i + IPI_RESCHEDULE,
 			   prec >= 4 ? " " : "");
-		for_each_present_cpu(cpu)
+		for_each_online_cpu(cpu)
 			seq_printf(p, "%10u ",
 				   __get_irq_stat(cpu, ipi_irqs[i]));
 		seq_printf(p, "      %s\n", ipi_types[i]);