1 files changed, 471 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
new file mode 100644
index 00000000000..ae1bd270f30
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -0,0 +1,471 @@
+/*
+ * SMP support for pSeries machines.
+ *
+ * Dave Engebretsen, Peter Bergner, and
+ * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
+ *
+ * Plus various changes from other IBM teams...
+ *
+ *      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.
+ */
+
+#undef DEBUG
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/cache.h>
+#include <linux/err.h>
+#include <linux/sysdev.h>
+#include <linux/cpu.h>
+
+#include <asm/ptrace.h>
+#include <asm/atomic.h>
+#include <asm/irq.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/smp.h>
+#include <asm/paca.h>
+#include <asm/time.h>
+#include <asm/machdep.h>
+#include <asm/xics.h>
+#include <asm/cputable.h>
+#include <asm/firmware.h>
+#include <asm/system.h>
+#include <asm/rtas.h>
+#include <asm/plpar_wrappers.h>
+#include <asm/pSeries_reconfig.h>
+#include <asm/mpic.h>
+
+#ifdef DEBUG
+#define DBG(fmt...) udbg_printf(fmt)
+#else
+#define DBG(fmt...)
+#endif
+
+/*
+ * The primary thread of each non-boot processor is recorded here before
+ * smp init.
+ */
+static cpumask_t of_spin_map;
+
+extern void pSeries_secondary_smp_init(unsigned long);
+
+#ifdef CONFIG_HOTPLUG_CPU
+
+/* Get state of physical CPU.
+ * Return codes:
+ *	0	- The processor is in the RTAS stopped state
+ *	1	- stop-self is in progress
+ *	2	- The processor is not in the RTAS stopped state
+ *	-1	- Hardware Error
+ *	-2	- Hardware Busy, Try again later.
+ */
+static int query_cpu_stopped(unsigned int pcpu)
+{
+	int cpu_status;
+	int status, qcss_tok;
+
+	qcss_tok = rtas_token("query-cpu-stopped-state");
+	if (qcss_tok == RTAS_UNKNOWN_SERVICE)
+		return -1;
+	status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu);
+	if (status != 0) {
+		printk(KERN_ERR
+		       "RTAS query-cpu-stopped-state failed: %i\n", status);
+		return status;
+	}
+
+	return cpu_status;
+}
+
+int pSeries_cpu_disable(void)
+{
+	int cpu = smp_processor_id();
+
+	cpu_clear(cpu, cpu_online_map);
+	systemcfg->processorCount--;
+
+	/*fix boot_cpuid here*/
+	if (cpu == boot_cpuid)
+		boot_cpuid = any_online_cpu(cpu_online_map);
+
+	/* FIXME: abstract this to not be platform specific later on */
+	xics_migrate_irqs_away();
+	return 0;
+}
+
+void pSeries_cpu_die(unsigned int cpu)
+{
+	int tries;
+	int cpu_status;
+	unsigned int pcpu = get_hard_smp_processor_id(cpu);
+
+	for (tries = 0; tries < 25; tries++) {
+		cpu_status = query_cpu_stopped(pcpu);
+		if (cpu_status == 0 || cpu_status == -1)
+			break;
+		msleep(200);
+	}
+	if (cpu_status != 0) {
+		printk("Querying DEAD? cpu %i (%i) shows %i\n",
+		       cpu, pcpu, cpu_status);
+	}
+
+	/* Isolation and deallocation are definatly 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_map 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_t candidate_map, tmp = CPU_MASK_NONE;
+	int err = -ENOSPC, len, nthreads, i;
+	u32 *intserv;
+
+	intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
+	if (!intserv)
+		return 0;
+
+	nthreads = len / sizeof(u32);
+	for (i = 0; i < nthreads; i++)
+		cpu_set(i, tmp);
+
+	lock_cpu_hotplug();
+
+	BUG_ON(!cpus_subset(cpu_present_map, cpu_possible_map));
+
+	/* Get a bitmap of unoccupied slots. */
+	cpus_xor(candidate_map, cpu_possible_map, cpu_present_map);
+	if (cpus_empty(candidate_map)) {
+		/* 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,
+		       cpus_weight(cpu_possible_map));
+		goto out_unlock;
+	}
+
+	while (!cpus_empty(tmp))
+		if (cpus_subset(tmp, candidate_map))
+			/* Found a range where we can insert the new cpu(s) */
+			break;
+		else
+			cpus_shift_left(tmp, tmp, nthreads);
+
+	if (cpus_empty(tmp)) {
+		printk(KERN_ERR "Unable to find space in cpu_present_map for"
+		       " processor %s with %d thread(s)\n", np->name,
+		       nthreads);
+		goto out_unlock;
+	}
+
+	for_each_cpu_mask(cpu, tmp) {
+		BUG_ON(cpu_isset(cpu, cpu_present_map));
+		cpu_set(cpu, cpu_present_map);
+		set_hard_smp_processor_id(cpu, *intserv++);
+	}
+	err = 0;
+out_unlock:
+	unlock_cpu_hotplug();
+	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;
+	u32 *intserv;
+
+	intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
+	if (!intserv)
+		return;
+
+	nthreads = len / sizeof(u32);
+
+	lock_cpu_hotplug();
+	for (i = 0; i < nthreads; i++) {
+		for_each_present_cpu(cpu) {
+			if (get_hard_smp_processor_id(cpu) != intserv[i])
+				continue;
+			BUG_ON(cpu_online(cpu));
+			cpu_clear(cpu, cpu_present_map);
+			set_hard_smp_processor_id(cpu, -1);
+			break;
+		}
+		if (cpu == NR_CPUS)
+			printk(KERN_WARNING "Could not find cpu to remove "
+			       "with physical id 0x%x\n", intserv[i]);
+	}
+	unlock_cpu_hotplug();
+}
+
+static int pSeries_smp_notifier(struct notifier_block *nb, unsigned long action, void *node)
+{
+	int err = NOTIFY_OK;
+
+	switch (action) {
+	case PSERIES_RECONFIG_ADD:
+		if (pSeries_add_processor(node))
+			err = NOTIFY_BAD;
+		break;
+	case PSERIES_RECONFIG_REMOVE:
+		pSeries_remove_processor(node);
+		break;
+	default:
+		err = NOTIFY_DONE;
+		break;
+	}
+	return err;
+}
+
+static struct notifier_block pSeries_smp_nb = {
+	.notifier_call = pSeries_smp_notifier,
+};
+
+#endif /* CONFIG_HOTPLUG_CPU */
+
+/**
+ * smp_startup_cpu() - start the given cpu
+ *
+ * At boot time, there is nothing to do for primary threads which were
+ * started from Open Firmware.  For anything else, call RTAS with the
+ * appropriate start location.
+ *
+ * Returns:
+ *	0	- failure
+ *	1	- success
+ */
+static inline int __devinit smp_startup_cpu(unsigned int lcpu)
+{
+	int status;
+	unsigned long start_here = __pa((u32)*((unsigned long *)
+					       pSeries_secondary_smp_init));
+	unsigned int pcpu;
+	int start_cpu;
+
+	if (cpu_isset(lcpu, of_spin_map))
+		/* Already started by OF and sitting in spin loop */
+		return 1;
+
+	pcpu = get_hard_smp_processor_id(lcpu);
+
+	/* Fixup atomic count: it exited inside IRQ handler. */
+	paca[lcpu].__current->thread_info->preempt_count	= 0;
+
+	/* 
+	 * If the RTAS start-cpu token does not exist then presume the
+	 * cpu is already spinning.
+	 */
+	start_cpu = rtas_token("start-cpu");
+	if (start_cpu == RTAS_UNKNOWN_SERVICE)
+		return 1;
+
+	status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, lcpu);
+	if (status != 0) {
+		printk(KERN_ERR "start-cpu failed: %i\n", status);
+		return 0;
+	}
+
+	return 1;
+}
+
+#ifdef CONFIG_XICS
+static inline void smp_xics_do_message(int cpu, int msg)
+{
+	set_bit(msg, &xics_ipi_message[cpu].value);
+	mb();
+	xics_cause_IPI(cpu);
+}
+
+static void smp_xics_message_pass(int target, int msg)
+{
+	unsigned int i;
+
+	if (target < NR_CPUS) {
+		smp_xics_do_message(target, msg);
+	} else {
+		for_each_online_cpu(i) {
+			if (target == MSG_ALL_BUT_SELF
+			    && i == smp_processor_id())
+				continue;
+			smp_xics_do_message(i, msg);
+		}
+	}
+}
+
+static int __init smp_xics_probe(void)
+{
+	xics_request_IPIs();
+
+	return cpus_weight(cpu_possible_map);
+}
+
+static void __devinit smp_xics_setup_cpu(int cpu)
+{
+	if (cpu != boot_cpuid)
+		xics_setup_cpu();
+
+	if (firmware_has_feature(FW_FEATURE_SPLPAR))
+		vpa_init(cpu);
+
+	cpu_clear(cpu, of_spin_map);
+
+}
+#endif /* CONFIG_XICS */
+
+static DEFINE_SPINLOCK(timebase_lock);
+static unsigned long timebase = 0;
+
+static void __devinit pSeries_give_timebase(void)
+{
+	spin_lock(&timebase_lock);
+	rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
+	timebase = get_tb();
+	spin_unlock(&timebase_lock);
+
+	while (timebase)
+		barrier();
+	rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
+}
+
+static void __devinit pSeries_take_timebase(void)
+{
+	while (!timebase)
+		barrier();
+	spin_lock(&timebase_lock);
+	set_tb(timebase >> 32, timebase & 0xffffffff);
+	timebase = 0;
+	spin_unlock(&timebase_lock);
+}
+
+static void __devinit smp_pSeries_kick_cpu(int nr)
+{
+	BUG_ON(nr < 0 || nr >= NR_CPUS);
+
+	if (!smp_startup_cpu(nr))
+		return;
+
+	/*
+	 * The processor is currently spinning, waiting for the
+	 * cpu_start field to become non-zero After we set cpu_start,
+	 * the processor will continue on to secondary_start
+	 */
+	paca[nr].cpu_start = 1;
+}
+
+static int smp_pSeries_cpu_bootable(unsigned int nr)
+{
+	/* Special case - we inhibit secondary thread startup
+	 * during boot if the user requests it.  Odd-numbered
+	 * cpus are assumed to be secondary threads.
+	 */
+	if (system_state < SYSTEM_RUNNING &&
+	    cpu_has_feature(CPU_FTR_SMT) &&
+	    !smt_enabled_at_boot && nr % 2 != 0)
+		return 0;
+
+	return 1;
+}
+#ifdef CONFIG_MPIC
+static struct smp_ops_t pSeries_mpic_smp_ops = {
+	.message_pass	= smp_mpic_message_pass,
+	.probe		= smp_mpic_probe,
+	.kick_cpu	= smp_pSeries_kick_cpu,
+	.setup_cpu	= smp_mpic_setup_cpu,
+};
+#endif
+#ifdef CONFIG_XICS
+static struct smp_ops_t pSeries_xics_smp_ops = {
+	.message_pass	= smp_xics_message_pass,
+	.probe		= smp_xics_probe,
+	.kick_cpu	= smp_pSeries_kick_cpu,
+	.setup_cpu	= smp_xics_setup_cpu,
+	.cpu_bootable	= smp_pSeries_cpu_bootable,
+};
+#endif
+
+/* This is called very early */
+void __init smp_init_pSeries(void)
+{
+	int i;
+
+	DBG(" -> smp_init_pSeries()\n");
+
+	switch (ppc64_interrupt_controller) {
+#ifdef CONFIG_MPIC
+	case IC_OPEN_PIC:
+		smp_ops = &pSeries_mpic_smp_ops;
+		break;
+#endif
+#ifdef CONFIG_XICS
+	case IC_PPC_XIC:
+		smp_ops = &pSeries_xics_smp_ops;
+		break;
+#endif
+	default:
+		panic("Invalid interrupt controller");
+	}
+
+#ifdef CONFIG_HOTPLUG_CPU
+	smp_ops->cpu_disable = pSeries_cpu_disable;
+	smp_ops->cpu_die = pSeries_cpu_die;
+
+	/* Processors can be added/removed only on LPAR */
+	if (systemcfg->platform == PLATFORM_PSERIES_LPAR)
+		pSeries_reconfig_notifier_register(&pSeries_smp_nb);
+#endif
+
+	/* Mark threads which are still spinning in hold loops. */
+	if (cpu_has_feature(CPU_FTR_SMT)) {
+		for_each_present_cpu(i) { 
+			if (i % 2 == 0)
+				/*
+				 * Even-numbered logical cpus correspond to
+				 * primary threads.
+				 */
+				cpu_set(i, of_spin_map);
+		}
+	} else {
+		of_spin_map = cpu_present_map;
+	}
+
+	cpu_clear(boot_cpuid, of_spin_map);
+
+	/* Non-lpar has additional take/give timebase */
+	if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
+		smp_ops->give_timebase = pSeries_give_timebase;
+		smp_ops->take_timebase = pSeries_take_timebase;
+	}
+
+	DBG(" <- smp_init_pSeries()\n");
+}
+