1 files changed, 275 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
new file mode 100644
index 000000000000..f460b9cbfd46
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -0,0 +1,275 @@
+/*
+ * 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/delay.h>
+#include <linux/cpu.h>
+#include <asm/system.h>
+#include <asm/prom.h>
+#include <asm/rtas.h>
+#include <asm/firmware.h>
+#include <asm/machdep.h>
+#include <asm/vdso_datapage.h>
+#include <asm/pSeries_reconfig.h>
+#include "xics.h"
+
+/* This version can't take the spinlock, because it never returns */
+static struct rtas_args rtas_stop_self_args = {
+        .token = RTAS_UNKNOWN_SERVICE,
+        .nargs = 0,
+        .nret = 1,
+        .rets = &rtas_stop_self_args.args[0],
+};
+
+static void rtas_stop_self(void)
+{
+        struct rtas_args *args = &rtas_stop_self_args;
+
+        local_irq_disable();
+
+        BUG_ON(args->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)
+{
+        local_irq_disable();
+        idle_task_exit();
+        xics_teardown_cpu(0);
+        rtas_stop_self();
+        /* Should never get here... */
+        BUG();
+        for(;;);
+}
+
+static int qcss_tok;    /* query-cpu-stopped-state token */
+
+/* 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, status;
+
+        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;
+        const u32 *intserv;
+
+        intserv = 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;
+        const u32 *intserv;
+
+        intserv = 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,
+};
+
+static int __init pseries_cpu_hotplug_init(void)
+{
+        rtas_stop_self_args.token = rtas_token("stop-self");
+        qcss_tok = rtas_token("query-cpu-stopped-state");
+
+        if (rtas_stop_self_args.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))
+                pSeries_reconfig_notifier_register(&pseries_smp_nb);
+
+        return 0;
+}
+arch_initcall(pseries_cpu_hotplug_init);