1 files changed, 427 insertions, 0 deletions

diff --git a/kernel/arch/powerpc/platforms/pseries/hotplug-cpu.c b/kernel/arch/powerpc/platforms/pseries/hotplug-cpu.c
new file mode 100644
index 000000000..62475440f
--- /dev/null
+++ b/kernel/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -0,0 +1,427 @@
+/*
+ * pseries CPU Hotplug infrastructure.
+ *
+ * Split out from arch/powerpc/platforms/pseries/setup.c
+ *  arch/powerpc/kernel/rtas.c, and arch/powerpc/platforms/pseries/smp.c
+ *
+ * Peter Bergner, IBM	March 2001.
+ * Copyright (C) 2001 IBM.
+ * Dave Engebretsen, Peter Bergner, and
+ * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
+ * Plus various changes from other IBM teams...
+ *
+ * Copyright (C) 2006 Michael Ellerman, IBM Corporation
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/sched.h>	/* for idle_task_exit */
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <asm/prom.h>
+#include <asm/rtas.h>
+#include <asm/firmware.h>
+#include <asm/machdep.h>
+#include <asm/vdso_datapage.h>
+#include <asm/xics.h>
+#include <asm/plpar_wrappers.h>
+
+#include "offline_states.h"
+
+/* This version can't take the spinlock, because it never returns */
+static int rtas_stop_self_token = RTAS_UNKNOWN_SERVICE;
+
+static DEFINE_PER_CPU(enum cpu_state_vals, preferred_offline_state) =
+							CPU_STATE_OFFLINE;
+static DEFINE_PER_CPU(enum cpu_state_vals, current_state) = CPU_STATE_OFFLINE;
+
+static enum cpu_state_vals default_offline_state = CPU_STATE_OFFLINE;
+
+static int cede_offline_enabled __read_mostly = 1;
+
+/*
+ * Enable/disable cede_offline when available.
+ */
+static int __init setup_cede_offline(char *str)
+{
+	if (!strcmp(str, "off"))
+		cede_offline_enabled = 0;
+	else if (!strcmp(str, "on"))
+		cede_offline_enabled = 1;
+	else
+		return 0;
+	return 1;
+}
+
+__setup("cede_offline=", setup_cede_offline);
+
+enum cpu_state_vals get_cpu_current_state(int cpu)
+{
+	return per_cpu(current_state, cpu);
+}
+
+void set_cpu_current_state(int cpu, enum cpu_state_vals state)
+{
+	per_cpu(current_state, cpu) = state;
+}
+
+enum cpu_state_vals get_preferred_offline_state(int cpu)
+{
+	return per_cpu(preferred_offline_state, cpu);
+}
+
+void set_preferred_offline_state(int cpu, enum cpu_state_vals state)
+{
+	per_cpu(preferred_offline_state, cpu) = state;
+}
+
+void set_default_offline_state(int cpu)
+{
+	per_cpu(preferred_offline_state, cpu) = default_offline_state;
+}
+
+static void rtas_stop_self(void)
+{
+	static struct rtas_args args = {
+		.nargs = 0,
+		.nret = cpu_to_be32(1),
+		.rets = &args.args[0],
+	};
+
+	args.token = cpu_to_be32(rtas_stop_self_token);
+
+	local_irq_disable();
+
+	BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
+
+	printk("cpu %u (hwid %u) Ready to die...\n",
+	       smp_processor_id(), hard_smp_processor_id());
+	enter_rtas(__pa(&args));
+
+	panic("Alas, I survived.\n");
+}
+
+static void pseries_mach_cpu_die(void)
+{
+	unsigned int cpu = smp_processor_id();
+	unsigned int hwcpu = hard_smp_processor_id();
+	u8 cede_latency_hint = 0;
+
+	local_irq_disable();
+	idle_task_exit();
+	xics_teardown_cpu();
+
+	if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
+		set_cpu_current_state(cpu, CPU_STATE_INACTIVE);
+		if (ppc_md.suspend_disable_cpu)
+			ppc_md.suspend_disable_cpu();
+
+		cede_latency_hint = 2;
+
+		get_lppaca()->idle = 1;
+		if (!lppaca_shared_proc(get_lppaca()))
+			get_lppaca()->donate_dedicated_cpu = 1;
+
+		while (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
+			while (!prep_irq_for_idle()) {
+				local_irq_enable();
+				local_irq_disable();
+			}
+
+			extended_cede_processor(cede_latency_hint);
+		}
+
+		local_irq_disable();
+
+		if (!lppaca_shared_proc(get_lppaca()))
+			get_lppaca()->donate_dedicated_cpu = 0;
+		get_lppaca()->idle = 0;
+
+		if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) {
+			unregister_slb_shadow(hwcpu);
+
+			hard_irq_disable();
+			/*
+			 * Call to start_secondary_resume() will not return.
+			 * Kernel stack will be reset and start_secondary()
+			 * will be called to continue the online operation.
+			 */
+			start_secondary_resume();
+		}
+	}
+
+	/* Requested state is CPU_STATE_OFFLINE at this point */
+	WARN_ON(get_preferred_offline_state(cpu) != CPU_STATE_OFFLINE);
+
+	set_cpu_current_state(cpu, CPU_STATE_OFFLINE);
+	unregister_slb_shadow(hwcpu);
+	rtas_stop_self();
+
+	/* Should never get here... */
+	BUG();
+	for(;;);
+}
+
+static int pseries_cpu_disable(void)
+{
+	int cpu = smp_processor_id();
+
+	set_cpu_online(cpu, false);
+	vdso_data->processorCount--;
+
+	/*fix boot_cpuid here*/
+	if (cpu == boot_cpuid)
+		boot_cpuid = cpumask_any(cpu_online_mask);
+
+	/* FIXME: abstract this to not be platform specific later on */
+	xics_migrate_irqs_away();
+	return 0;
+}
+
+/*
+ * pseries_cpu_die: Wait for the cpu to die.
+ * @cpu: logical processor id of the CPU whose death we're awaiting.
+ *
+ * This function is called from the context of the thread which is performing
+ * the cpu-offline. Here we wait for long enough to allow the cpu in question
+ * to self-destroy so that the cpu-offline thread can send the CPU_DEAD
+ * notifications.
+ *
+ * OTOH, pseries_mach_cpu_die() is called by the @cpu when it wants to
+ * self-destruct.
+ */
+static void pseries_cpu_die(unsigned int cpu)
+{
+	int tries;
+	int cpu_status = 1;
+	unsigned int pcpu = get_hard_smp_processor_id(cpu);
+
+	if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) {
+		cpu_status = 1;
+		for (tries = 0; tries < 5000; tries++) {
+			if (get_cpu_current_state(cpu) == CPU_STATE_INACTIVE) {
+				cpu_status = 0;
+				break;
+			}
+			msleep(1);
+		}
+	} else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) {
+
+		for (tries = 0; tries < 25; tries++) {
+			cpu_status = smp_query_cpu_stopped(pcpu);
+			if (cpu_status == QCSS_STOPPED ||
+			    cpu_status == QCSS_HARDWARE_ERROR)
+				break;
+			cpu_relax();
+		}
+	}
+
+	if (cpu_status != 0) {
+		printk("Querying DEAD? cpu %i (%i) shows %i\n",
+		       cpu, pcpu, cpu_status);
+	}
+
+	/* Isolation and deallocation are definitely done by
+	 * drslot_chrp_cpu.  If they were not they would be
+	 * done here.  Change isolate state to Isolate and
+	 * change allocation-state to Unusable.
+	 */
+	paca[cpu].cpu_start = 0;
+}
+
+/*
+ * Update cpu_present_mask and paca(s) for a new cpu node.  The wrinkle
+ * here is that a cpu device node may represent up to two logical cpus
+ * in the SMT case.  We must honor the assumption in other code that
+ * the logical ids for sibling SMT threads x and y are adjacent, such
+ * that x^1 == y and y^1 == x.
+ */
+static int pseries_add_processor(struct device_node *np)
+{
+	unsigned int cpu;
+	cpumask_var_t candidate_mask, tmp;
+	int err = -ENOSPC, len, nthreads, i;
+	const __be32 *intserv;
+
+	intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
+	if (!intserv)
+		return 0;
+
+	zalloc_cpumask_var(&candidate_mask, GFP_KERNEL);
+	zalloc_cpumask_var(&tmp, GFP_KERNEL);
+
+	nthreads = len / sizeof(u32);
+	for (i = 0; i < nthreads; i++)
+		cpumask_set_cpu(i, tmp);
+
+	cpu_maps_update_begin();
+
+	BUG_ON(!cpumask_subset(cpu_present_mask, cpu_possible_mask));
+
+	/* Get a bitmap of unoccupied slots. */
+	cpumask_xor(candidate_mask, cpu_possible_mask, cpu_present_mask);
+	if (cpumask_empty(candidate_mask)) {
+		/* If we get here, it most likely means that NR_CPUS is
+		 * less than the partition's max processors setting.
+		 */
+		printk(KERN_ERR "Cannot add cpu %s; this system configuration"
+		       " supports %d logical cpus.\n", np->full_name,
+		       num_possible_cpus());
+		goto out_unlock;
+	}
+
+	while (!cpumask_empty(tmp))
+		if (cpumask_subset(tmp, candidate_mask))
+			/* Found a range where we can insert the new cpu(s) */
+			break;
+		else
+			cpumask_shift_left(tmp, tmp, nthreads);
+
+	if (cpumask_empty(tmp)) {
+		printk(KERN_ERR "Unable to find space in cpu_present_mask for"
+		       " processor %s with %d thread(s)\n", np->name,
+		       nthreads);
+		goto out_unlock;
+	}
+
+	for_each_cpu(cpu, tmp) {
+		BUG_ON(cpu_present(cpu));
+		set_cpu_present(cpu, true);
+		set_hard_smp_processor_id(cpu, be32_to_cpu(*intserv++));
+	}
+	err = 0;
+out_unlock:
+	cpu_maps_update_done();
+	free_cpumask_var(candidate_mask);
+	free_cpumask_var(tmp);
+	return err;
+}
+
+/*
+ * Update the present map for a cpu node which is going away, and set
+ * the hard id in the paca(s) to -1 to be consistent with boot time
+ * convention for non-present cpus.
+ */
+static void pseries_remove_processor(struct device_node *np)
+{
+	unsigned int cpu;
+	int len, nthreads, i;
+	const __be32 *intserv;
+	u32 thread;
+
+	intserv = of_get_property(np, "ibm,ppc-interrupt-server#s", &len);
+	if (!intserv)
+		return;
+
+	nthreads = len / sizeof(u32);
+
+	cpu_maps_update_begin();
+	for (i = 0; i < nthreads; i++) {
+		thread = be32_to_cpu(intserv[i]);
+		for_each_present_cpu(cpu) {
+			if (get_hard_smp_processor_id(cpu) != thread)
+				continue;
+			BUG_ON(cpu_online(cpu));
+			set_cpu_present(cpu, false);
+			set_hard_smp_processor_id(cpu, -1);
+			break;
+		}
+		if (cpu >= nr_cpu_ids)
+			printk(KERN_WARNING "Could not find cpu to remove "
+			       "with physical id 0x%x\n", thread);
+	}
+	cpu_maps_update_done();
+}
+
+static int pseries_smp_notifier(struct notifier_block *nb,
+				unsigned long action, void *data)
+{
+	struct of_reconfig_data *rd = data;
+	int err = 0;
+
+	switch (action) {
+	case OF_RECONFIG_ATTACH_NODE:
+		err = pseries_add_processor(rd->dn);
+		break;
+	case OF_RECONFIG_DETACH_NODE:
+		pseries_remove_processor(rd->dn);
+		break;
+	}
+	return notifier_from_errno(err);
+}
+
+static struct notifier_block pseries_smp_nb = {
+	.notifier_call = pseries_smp_notifier,
+};
+
+#define MAX_CEDE_LATENCY_LEVELS		4
+#define	CEDE_LATENCY_PARAM_LENGTH	10
+#define CEDE_LATENCY_PARAM_MAX_LENGTH	\
+	(MAX_CEDE_LATENCY_LEVELS * CEDE_LATENCY_PARAM_LENGTH * sizeof(char))
+#define CEDE_LATENCY_TOKEN		45
+
+static char cede_parameters[CEDE_LATENCY_PARAM_MAX_LENGTH];
+
+static int parse_cede_parameters(void)
+{
+	memset(cede_parameters, 0, CEDE_LATENCY_PARAM_MAX_LENGTH);
+	return rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,
+			 NULL,
+			 CEDE_LATENCY_TOKEN,
+			 __pa(cede_parameters),
+			 CEDE_LATENCY_PARAM_MAX_LENGTH);
+}
+
+static int __init pseries_cpu_hotplug_init(void)
+{
+	struct device_node *np;
+	const char *typep;
+	int cpu;
+	int qcss_tok;
+
+	for_each_node_by_name(np, "interrupt-controller") {
+		typep = of_get_property(np, "compatible", NULL);
+		if (strstr(typep, "open-pic")) {
+			of_node_put(np);
+
+			printk(KERN_INFO "CPU Hotplug not supported on "
+				"systems using MPIC\n");
+			return 0;
+		}
+	}
+
+	rtas_stop_self_token = rtas_token("stop-self");
+	qcss_tok = rtas_token("query-cpu-stopped-state");
+
+	if (rtas_stop_self_token == RTAS_UNKNOWN_SERVICE ||
+			qcss_tok == RTAS_UNKNOWN_SERVICE) {
+		printk(KERN_INFO "CPU Hotplug not supported by firmware "
+				"- disabling.\n");
+		return 0;
+	}
+
+	ppc_md.cpu_die = pseries_mach_cpu_die;
+	smp_ops->cpu_disable = pseries_cpu_disable;
+	smp_ops->cpu_die = pseries_cpu_die;
+
+	/* Processors can be added/removed only on LPAR */
+	if (firmware_has_feature(FW_FEATURE_LPAR)) {
+		of_reconfig_notifier_register(&pseries_smp_nb);
+		cpu_maps_update_begin();
+		if (cede_offline_enabled && parse_cede_parameters() == 0) {
+			default_offline_state = CPU_STATE_INACTIVE;
+			for_each_online_cpu(cpu)
+				set_default_offline_state(cpu);
+		}
+		cpu_maps_update_done();
+	}
+
+	return 0;
+}
+machine_arch_initcall(pseries, pseries_cpu_hotplug_init);