--- /dev/null
+/*
+ * 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 "xics.h"
+#include <asm/cputable.h>
+#include <asm/firmware.h>
+#include <asm/system.h>
+#include <asm/rtas.h>
+#include <asm/pSeries_reconfig.h>
+#include <asm/mpic.h>
+#include <asm/vdso_datapage.h>
+
+#include "plpar_wrappers.h"
+
+#ifdef DEBUG
+#include <asm/udbg.h>
+#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;
+}
+
+static int pSeries_cpu_disable(void)
+{
+ int cpu = smp_processor_id();
+
+ cpu_clear(cpu, cpu_online_map);
+ vdso_data->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;
+}
+
+static 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. */
+ task_thread_info(paca[lcpu].__current)->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, pcpu);
+ 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 (firmware_has_feature(FW_FEATURE_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");
+}
+
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