Linux-2.6.12-rc2

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / arch / ppc64 / kernel / pSeries_smp.c

/*
 * 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/system.h>
#include <asm/rtas.h>
#include <asm/plpar_wrappers.h>
#include <asm/pSeries_reconfig.h>

#include "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)
{
        systemcfg->processorCount--;

        /*fix boot_cpuid here*/
        if (smp_processor_id() == 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;

        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;

        status = rtas_call(rtas_token("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;
}

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 (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR)
                vpa_init(cpu);

        cpu_clear(cpu, of_spin_map);

        /*
         * Put the calling processor into the GIQ.  This is really only
         * necessary from a secondary thread as the OF start-cpu interface
         * performs this function for us on primary threads.
         */
        rtas_set_indicator(GLOBAL_INTERRUPT_QUEUE,
                (1UL << interrupt_server_size) - 1 - default_distrib_server, 1);
}

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 &&
            cur_cpu_spec->cpu_features & CPU_FTR_SMT &&
            !smt_enabled_at_boot && nr % 2 != 0)
                return 0;

        return 1;
}

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,
};

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,
};

/* This is called very early */
void __init smp_init_pSeries(void)
{
        int i;

        DBG(" -> smp_init_pSeries()\n");

        if (ppc64_interrupt_controller == IC_OPEN_PIC)
                smp_ops = &pSeries_mpic_smp_ops;
        else
                smp_ops = &pSeries_xics_smp_ops;

#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 (cur_cpu_spec->cpu_features & 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");
}