[SPARC64]: Fix new context version SMP handling.

[deliverable/linux.git] / arch / sparc64 / kernel / smp.c

/* smp.c: Sparc64 SMP support.
 *
 * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/cache.h>
#include <linux/jiffies.h>
#include <linux/profile.h>
#include <linux/bootmem.h>

#include <asm/head.h>
#include <asm/ptrace.h>
#include <asm/atomic.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/cpudata.h>

#include <asm/irq.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/oplib.h>
#include <asm/uaccess.h>
#include <asm/timer.h>
#include <asm/starfire.h>
#include <asm/tlb.h>
#include <asm/sections.h>

extern void calibrate_delay(void);

/* Please don't make this stuff initdata!!!  --DaveM */
static unsigned char boot_cpu_id;

cpumask_t cpu_online_map __read_mostly = CPU_MASK_NONE;
cpumask_t phys_cpu_present_map __read_mostly = CPU_MASK_NONE;
static cpumask_t smp_commenced_mask;
static cpumask_t cpu_callout_map;

void smp_info(struct seq_file *m)
{
        int i;
        
        seq_printf(m, "State:\n");
        for (i = 0; i < NR_CPUS; i++) {
                if (cpu_online(i))
                        seq_printf(m,
                                   "CPU%d:\t\tonline\n", i);
        }
}

void smp_bogo(struct seq_file *m)
{
        int i;
        
        for (i = 0; i < NR_CPUS; i++)
                if (cpu_online(i))
                        seq_printf(m,
                                   "Cpu%dBogo\t: %lu.%02lu\n"
                                   "Cpu%dClkTck\t: %016lx\n",
                                   i, cpu_data(i).udelay_val / (500000/HZ),
                                   (cpu_data(i).udelay_val / (5000/HZ)) % 100,
                                   i, cpu_data(i).clock_tick);
}

void __init smp_store_cpu_info(int id)
{
        int cpu_node, def;

        /* multiplier and counter set by
           smp_setup_percpu_timer()  */
        cpu_data(id).udelay_val                 = loops_per_jiffy;

        cpu_find_by_mid(id, &cpu_node);
        cpu_data(id).clock_tick = prom_getintdefault(cpu_node,
                                                     "clock-frequency", 0);

        def = ((tlb_type == hypervisor) ? (8 * 1024) : (16 * 1024));
        cpu_data(id).dcache_size = prom_getintdefault(cpu_node, "dcache-size",
                                                      def);

        def = 32;
        cpu_data(id).dcache_line_size =
                prom_getintdefault(cpu_node, "dcache-line-size", def);

        def = 16 * 1024;
        cpu_data(id).icache_size = prom_getintdefault(cpu_node, "icache-size",
                                                      def);

        def = 32;
        cpu_data(id).icache_line_size =
                prom_getintdefault(cpu_node, "icache-line-size", def);

        def = ((tlb_type == hypervisor) ?
               (3 * 1024 * 1024) :
               (4 * 1024 * 1024));
        cpu_data(id).ecache_size = prom_getintdefault(cpu_node, "ecache-size",
                                                      def);

        def = 64;
        cpu_data(id).ecache_line_size =
                prom_getintdefault(cpu_node, "ecache-line-size", def);

        printk("CPU[%d]: Caches "
               "D[sz(%d):line_sz(%d)] "
               "I[sz(%d):line_sz(%d)] "
               "E[sz(%d):line_sz(%d)]\n",
               id,
               cpu_data(id).dcache_size, cpu_data(id).dcache_line_size,
               cpu_data(id).icache_size, cpu_data(id).icache_line_size,
               cpu_data(id).ecache_size, cpu_data(id).ecache_line_size);
}

static void smp_setup_percpu_timer(void);

static volatile unsigned long callin_flag = 0;

void __init smp_callin(void)
{
        int cpuid = hard_smp_processor_id();

        __local_per_cpu_offset = __per_cpu_offset(cpuid);

        if (tlb_type == hypervisor)
                sun4v_ktsb_register();

        __flush_tlb_all();

        smp_setup_percpu_timer();

        if (cheetah_pcache_forced_on)
                cheetah_enable_pcache();

        local_irq_enable();

        calibrate_delay();
        smp_store_cpu_info(cpuid);
        callin_flag = 1;
        __asm__ __volatile__("membar #Sync\n\t"
                             "flush  %%g6" : : : "memory");

        /* Clear this or we will die instantly when we
         * schedule back to this idler...
         */
        current_thread_info()->new_child = 0;

        /* Attach to the address space of init_task. */
        atomic_inc(&init_mm.mm_count);
        current->active_mm = &init_mm;

        while (!cpu_isset(cpuid, smp_commenced_mask))
                rmb();

        cpu_set(cpuid, cpu_online_map);

        /* idle thread is expected to have preempt disabled */
        preempt_disable();
}

void cpu_panic(void)
{
        printk("CPU[%d]: Returns from cpu_idle!\n", smp_processor_id());
        panic("SMP bolixed\n");
}

static unsigned long current_tick_offset __read_mostly;

/* This tick register synchronization scheme is taken entirely from
 * the ia64 port, see arch/ia64/kernel/smpboot.c for details and credit.
 *
 * The only change I've made is to rework it so that the master
 * initiates the synchonization instead of the slave. -DaveM
 */

#define MASTER  0
#define SLAVE   (SMP_CACHE_BYTES/sizeof(unsigned long))

#define NUM_ROUNDS      64      /* magic value */
#define NUM_ITERS       5       /* likewise */

static DEFINE_SPINLOCK(itc_sync_lock);
static unsigned long go[SLAVE + 1];

#define DEBUG_TICK_SYNC 0

static inline long get_delta (long *rt, long *master)
{
        unsigned long best_t0 = 0, best_t1 = ~0UL, best_tm = 0;
        unsigned long tcenter, t0, t1, tm;
        unsigned long i;

        for (i = 0; i < NUM_ITERS; i++) {
                t0 = tick_ops->get_tick();
                go[MASTER] = 1;
                membar_storeload();
                while (!(tm = go[SLAVE]))
                        rmb();
                go[SLAVE] = 0;
                wmb();
                t1 = tick_ops->get_tick();

                if (t1 - t0 < best_t1 - best_t0)
                        best_t0 = t0, best_t1 = t1, best_tm = tm;
        }

        *rt = best_t1 - best_t0;
        *master = best_tm - best_t0;

        /* average best_t0 and best_t1 without overflow: */
        tcenter = (best_t0/2 + best_t1/2);
        if (best_t0 % 2 + best_t1 % 2 == 2)
                tcenter++;
        return tcenter - best_tm;
}

void smp_synchronize_tick_client(void)
{
        long i, delta, adj, adjust_latency = 0, done = 0;
        unsigned long flags, rt, master_time_stamp, bound;
#if DEBUG_TICK_SYNC
        struct {
                long rt;        /* roundtrip time */
                long master;    /* master's timestamp */
                long diff;      /* difference between midpoint and master's timestamp */
                long lat;       /* estimate of itc adjustment latency */
        } t[NUM_ROUNDS];
#endif

        go[MASTER] = 1;

        while (go[MASTER])
                rmb();

        local_irq_save(flags);
        {
                for (i = 0; i < NUM_ROUNDS; i++) {
                        delta = get_delta(&rt, &master_time_stamp);
                        if (delta == 0) {
                                done = 1;       /* let's lock on to this... */
                                bound = rt;
                        }

                        if (!done) {
                                if (i > 0) {
                                        adjust_latency += -delta;
                                        adj = -delta + adjust_latency/4;
                                } else
                                        adj = -delta;

                                tick_ops->add_tick(adj, current_tick_offset);
                        }
#if DEBUG_TICK_SYNC
                        t[i].rt = rt;
                        t[i].master = master_time_stamp;
                        t[i].diff = delta;
                        t[i].lat = adjust_latency/4;
#endif
                }
        }
        local_irq_restore(flags);

#if DEBUG_TICK_SYNC
        for (i = 0; i < NUM_ROUNDS; i++)
                printk("rt=%5ld master=%5ld diff=%5ld adjlat=%5ld\n",
                       t[i].rt, t[i].master, t[i].diff, t[i].lat);
#endif

        printk(KERN_INFO "CPU %d: synchronized TICK with master CPU (last diff %ld cycles,"
               "maxerr %lu cycles)\n", smp_processor_id(), delta, rt);
}

static void smp_start_sync_tick_client(int cpu);

static void smp_synchronize_one_tick(int cpu)
{
        unsigned long flags, i;

        go[MASTER] = 0;

        smp_start_sync_tick_client(cpu);

        /* wait for client to be ready */
        while (!go[MASTER])
                rmb();

        /* now let the client proceed into his loop */
        go[MASTER] = 0;
        membar_storeload();

        spin_lock_irqsave(&itc_sync_lock, flags);
        {
                for (i = 0; i < NUM_ROUNDS*NUM_ITERS; i++) {
                        while (!go[MASTER])
                                rmb();
                        go[MASTER] = 0;
                        wmb();
                        go[SLAVE] = tick_ops->get_tick();
                        membar_storeload();
                }
        }
        spin_unlock_irqrestore(&itc_sync_lock, flags);
}

extern void sun4v_init_mondo_queues(int use_bootmem, int cpu, int alloc, int load);

extern unsigned long sparc64_cpu_startup;

/* The OBP cpu startup callback truncates the 3rd arg cookie to
 * 32-bits (I think) so to be safe we have it read the pointer
 * contained here so we work on >4GB machines. -DaveM
 */
static struct thread_info *cpu_new_thread = NULL;

static int __devinit smp_boot_one_cpu(unsigned int cpu)
{
        unsigned long entry =
                (unsigned long)(&sparc64_cpu_startup);
        unsigned long cookie =
                (unsigned long)(&cpu_new_thread);
        struct task_struct *p;
        int timeout, ret;

        p = fork_idle(cpu);
        callin_flag = 0;
        cpu_new_thread = task_thread_info(p);
        cpu_set(cpu, cpu_callout_map);

        if (tlb_type == hypervisor) {
                /* Alloc the mondo queues, cpu will load them.  */
                sun4v_init_mondo_queues(0, cpu, 1, 0);

                prom_startcpu_cpuid(cpu, entry, cookie);
        } else {
                int cpu_node;

                cpu_find_by_mid(cpu, &cpu_node);
                prom_startcpu(cpu_node, entry, cookie);
        }

        for (timeout = 0; timeout < 5000000; timeout++) {
                if (callin_flag)
                        break;
                udelay(100);
        }

        if (callin_flag) {
                ret = 0;
        } else {
                printk("Processor %d is stuck.\n", cpu);
                cpu_clear(cpu, cpu_callout_map);
                ret = -ENODEV;
        }
        cpu_new_thread = NULL;

        return ret;
}

static void spitfire_xcall_helper(u64 data0, u64 data1, u64 data2, u64 pstate, unsigned long cpu)
{
        u64 result, target;
        int stuck, tmp;

        if (this_is_starfire) {
                /* map to real upaid */
                cpu = (((cpu & 0x3c) << 1) |
                        ((cpu & 0x40) >> 4) |
                        (cpu & 0x3));
        }

        target = (cpu << 14) | 0x70;
again:
        /* Ok, this is the real Spitfire Errata #54.
         * One must read back from a UDB internal register
         * after writes to the UDB interrupt dispatch, but
         * before the membar Sync for that write.
         * So we use the high UDB control register (ASI 0x7f,
         * ADDR 0x20) for the dummy read. -DaveM
         */
        tmp = 0x40;
        __asm__ __volatile__(
        "wrpr   %1, %2, %%pstate\n\t"
        "stxa   %4, [%0] %3\n\t"
        "stxa   %5, [%0+%8] %3\n\t"
        "add    %0, %8, %0\n\t"
        "stxa   %6, [%0+%8] %3\n\t"
        "membar #Sync\n\t"
        "stxa   %%g0, [%7] %3\n\t"
        "membar #Sync\n\t"
        "mov    0x20, %%g1\n\t"
        "ldxa   [%%g1] 0x7f, %%g0\n\t"
        "membar #Sync"
        : "=r" (tmp)
        : "r" (pstate), "i" (PSTATE_IE), "i" (ASI_INTR_W),
          "r" (data0), "r" (data1), "r" (data2), "r" (target),
          "r" (0x10), "0" (tmp)
        : "g1");

        /* NOTE: PSTATE_IE is still clear. */
        stuck = 100000;
        do {
                __asm__ __volatile__("ldxa [%%g0] %1, %0"
                        : "=r" (result)
                        : "i" (ASI_INTR_DISPATCH_STAT));
                if (result == 0) {
                        __asm__ __volatile__("wrpr %0, 0x0, %%pstate"
                                             : : "r" (pstate));
                        return;
                }
                stuck -= 1;
                if (stuck == 0)
                        break;
        } while (result & 0x1);
        __asm__ __volatile__("wrpr %0, 0x0, %%pstate"
                             : : "r" (pstate));
        if (stuck == 0) {
                printk("CPU[%d]: mondo stuckage result[%016lx]\n",
                       smp_processor_id(), result);
        } else {
                udelay(2);
                goto again;
        }
}

static __inline__ void spitfire_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mask)
{
        u64 pstate;
        int i;

        __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
        for_each_cpu_mask(i, mask)
                spitfire_xcall_helper(data0, data1, data2, pstate, i);
}

/* Cheetah now allows to send the whole 64-bytes of data in the interrupt
 * packet, but we have no use for that.  However we do take advantage of
 * the new pipelining feature (ie. dispatch to multiple cpus simultaneously).
 */
static void cheetah_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mask)
{
        u64 pstate, ver;
        int nack_busy_id, is_jbus;

        if (cpus_empty(mask))
                return;

        /* Unfortunately, someone at Sun had the brilliant idea to make the
         * busy/nack fields hard-coded by ITID number for this Ultra-III
         * derivative processor.
         */
        __asm__ ("rdpr %%ver, %0" : "=r" (ver));
        is_jbus = ((ver >> 32) == __JALAPENO_ID ||
                   (ver >> 32) == __SERRANO_ID);

        __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));

retry:
        __asm__ __volatile__("wrpr %0, %1, %%pstate\n\t"
                             : : "r" (pstate), "i" (PSTATE_IE));

        /* Setup the dispatch data registers. */
        __asm__ __volatile__("stxa      %0, [%3] %6\n\t"
                             "stxa      %1, [%4] %6\n\t"
                             "stxa      %2, [%5] %6\n\t"
                             "membar    #Sync\n\t"
                             : /* no outputs */
                             : "r" (data0), "r" (data1), "r" (data2),
                               "r" (0x40), "r" (0x50), "r" (0x60),
                               "i" (ASI_INTR_W));

        nack_busy_id = 0;
        {
                int i;

                for_each_cpu_mask(i, mask) {
                        u64 target = (i << 14) | 0x70;

                        if (!is_jbus)
                                target |= (nack_busy_id << 24);
                        __asm__ __volatile__(
                                "stxa   %%g0, [%0] %1\n\t"
                                "membar #Sync\n\t"
                                : /* no outputs */
                                : "r" (target), "i" (ASI_INTR_W));
                        nack_busy_id++;
                }
        }

        /* Now, poll for completion. */
        {
                u64 dispatch_stat;
                long stuck;

                stuck = 100000 * nack_busy_id;
                do {
                        __asm__ __volatile__("ldxa      [%%g0] %1, %0"
                                             : "=r" (dispatch_stat)
                                             : "i" (ASI_INTR_DISPATCH_STAT));
                        if (dispatch_stat == 0UL) {
                                __asm__ __volatile__("wrpr %0, 0x0, %%pstate"
                                                     : : "r" (pstate));
                                return;
                        }
                        if (!--stuck)
                                break;
                } while (dispatch_stat & 0x5555555555555555UL);

                __asm__ __volatile__("wrpr %0, 0x0, %%pstate"
                                     : : "r" (pstate));

                if ((dispatch_stat & ~(0x5555555555555555UL)) == 0) {
                        /* Busy bits will not clear, continue instead
                         * of freezing up on this cpu.
                         */
                        printk("CPU[%d]: mondo stuckage result[%016lx]\n",
                               smp_processor_id(), dispatch_stat);
                } else {
                        int i, this_busy_nack = 0;

                        /* Delay some random time with interrupts enabled
                         * to prevent deadlock.
                         */
                        udelay(2 * nack_busy_id);

                        /* Clear out the mask bits for cpus which did not
                         * NACK us.
                         */
                        for_each_cpu_mask(i, mask) {
                                u64 check_mask;

                                if (is_jbus)
                                        check_mask = (0x2UL << (2*i));
                                else
                                        check_mask = (0x2UL <<
                                                      this_busy_nack);
                                if ((dispatch_stat & check_mask) == 0)
                                        cpu_clear(i, mask);
                                this_busy_nack += 2;
                        }

                        goto retry;
                }
        }
}

/* Multi-cpu list version.  */
static void hypervisor_xcall_deliver(u64 data0, u64 data1, u64 data2, cpumask_t mask)
{
        struct trap_per_cpu *tb;
        u16 *cpu_list;
        u64 *mondo;
        cpumask_t error_mask;
        unsigned long flags, status;
        int cnt, retries, this_cpu, prev_sent, i;

        /* We have to do this whole thing with interrupts fully disabled.
         * Otherwise if we send an xcall from interrupt context it will
         * corrupt both our mondo block and cpu list state.
         *
         * One consequence of this is that we cannot use timeout mechanisms
         * that depend upon interrupts being delivered locally.  So, for
         * example, we cannot sample jiffies and expect it to advance.
         *
         * Fortunately, udelay() uses %stick/%tick so we can use that.
         */
        local_irq_save(flags);

        this_cpu = smp_processor_id();
        tb = &trap_block[this_cpu];

        mondo = __va(tb->cpu_mondo_block_pa);
        mondo[0] = data0;
        mondo[1] = data1;
        mondo[2] = data2;
        wmb();

        cpu_list = __va(tb->cpu_list_pa);

        /* Setup the initial cpu list.  */
        cnt = 0;
        for_each_cpu_mask(i, mask)
                cpu_list[cnt++] = i;

        cpus_clear(error_mask);
        retries = 0;
        prev_sent = 0;
        do {
                int forward_progress, n_sent;

                status = sun4v_cpu_mondo_send(cnt,
                                              tb->cpu_list_pa,
                                              tb->cpu_mondo_block_pa);

                /* HV_EOK means all cpus received the xcall, we're done.  */
                if (likely(status == HV_EOK))
                        break;

                /* First, see if we made any forward progress.
                 *
                 * The hypervisor indicates successful sends by setting
                 * cpu list entries to the value 0xffff.
                 */
                n_sent = 0;
                for (i = 0; i < cnt; i++) {
                        if (likely(cpu_list[i] == 0xffff))
                                n_sent++;
                }

                forward_progress = 0;
                if (n_sent > prev_sent)
                        forward_progress = 1;

                prev_sent = n_sent;

                /* If we get a HV_ECPUERROR, then one or more of the cpus
                 * in the list are in error state.  Use the cpu_state()
                 * hypervisor call to find out which cpus are in error state.
                 */
                if (unlikely(status == HV_ECPUERROR)) {
                        for (i = 0; i < cnt; i++) {
                                long err;
                                u16 cpu;

                                cpu = cpu_list[i];
                                if (cpu == 0xffff)
                                        continue;

                                err = sun4v_cpu_state(cpu);
                                if (err >= 0 &&
                                    err == HV_CPU_STATE_ERROR) {
                                        cpu_list[i] = 0xffff;
                                        cpu_set(cpu, error_mask);
                                }
                        }
                } else if (unlikely(status != HV_EWOULDBLOCK))
                        goto fatal_mondo_error;

                /* Don't bother rewriting the CPU list, just leave the
                 * 0xffff and non-0xffff entries in there and the
                 * hypervisor will do the right thing.
                 *
                 * Only advance timeout state if we didn't make any
                 * forward progress.
                 */
                if (unlikely(!forward_progress)) {
                        if (unlikely(++retries > 10000))
                                goto fatal_mondo_timeout;

                        /* Delay a little bit to let other cpus catch up
                         * on their cpu mondo queue work.
                         */
                        udelay(2 * cnt);
                }
        } while (1);

        local_irq_restore(flags);

        if (unlikely(!cpus_empty(error_mask)))
                goto fatal_mondo_cpu_error;

        return;

fatal_mondo_cpu_error:
        printk(KERN_CRIT "CPU[%d]: SUN4V mondo cpu error, some target cpus "
               "were in error state\n",
               this_cpu);
        printk(KERN_CRIT "CPU[%d]: Error mask [ ", this_cpu);
        for_each_cpu_mask(i, error_mask)
                printk("%d ", i);
        printk("]\n");
        return;

fatal_mondo_timeout:
        local_irq_restore(flags);
        printk(KERN_CRIT "CPU[%d]: SUN4V mondo timeout, no forward "
               " progress after %d retries.\n",
               this_cpu, retries);
        goto dump_cpu_list_and_out;

fatal_mondo_error:
        local_irq_restore(flags);
        printk(KERN_CRIT "CPU[%d]: Unexpected SUN4V mondo error %lu\n",
               this_cpu, status);
        printk(KERN_CRIT "CPU[%d]: Args were cnt(%d) cpulist_pa(%lx) "
               "mondo_block_pa(%lx)\n",
               this_cpu, cnt, tb->cpu_list_pa, tb->cpu_mondo_block_pa);

dump_cpu_list_and_out:
        printk(KERN_CRIT "CPU[%d]: CPU list [ ", this_cpu);
        for (i = 0; i < cnt; i++)
                printk("%u ", cpu_list[i]);
        printk("]\n");
}

/* Send cross call to all processors mentioned in MASK
 * except self.
 */
static void smp_cross_call_masked(unsigned long *func, u32 ctx, u64 data1, u64 data2, cpumask_t mask)
{
        u64 data0 = (((u64)ctx)<<32 | (((u64)func) & 0xffffffff));
        int this_cpu = get_cpu();

        cpus_and(mask, mask, cpu_online_map);
        cpu_clear(this_cpu, mask);

        if (tlb_type == spitfire)
                spitfire_xcall_deliver(data0, data1, data2, mask);
        else if (tlb_type == cheetah || tlb_type == cheetah_plus)
                cheetah_xcall_deliver(data0, data1, data2, mask);
        else
                hypervisor_xcall_deliver(data0, data1, data2, mask);
        /* NOTE: Caller runs local copy on master. */

        put_cpu();
}

extern unsigned long xcall_sync_tick;

static void smp_start_sync_tick_client(int cpu)
{
        cpumask_t mask = cpumask_of_cpu(cpu);

        smp_cross_call_masked(&xcall_sync_tick,
                              0, 0, 0, mask);
}

/* Send cross call to all processors except self. */
#define smp_cross_call(func, ctx, data1, data2) \
        smp_cross_call_masked(func, ctx, data1, data2, cpu_online_map)

struct call_data_struct {
        void (*func) (void *info);
        void *info;
        atomic_t finished;
        int wait;
};

static DEFINE_SPINLOCK(call_lock);
static struct call_data_struct *call_data;

extern unsigned long xcall_call_function;

/*
 * You must not call this function with disabled interrupts or from a
 * hardware interrupt handler or from a bottom half handler.
 */
static int smp_call_function_mask(void (*func)(void *info), void *info,
                                  int nonatomic, int wait, cpumask_t mask)
{
        struct call_data_struct data;
        int cpus;
        long timeout;

        /* Can deadlock when called with interrupts disabled */
        WARN_ON(irqs_disabled());

        data.func = func;
        data.info = info;
        atomic_set(&data.finished, 0);
        data.wait = wait;

        spin_lock(&call_lock);

        cpu_clear(smp_processor_id(), mask);
        cpus = cpus_weight(mask);
        if (!cpus)
                goto out_unlock;

        call_data = &data;

        smp_cross_call_masked(&xcall_call_function, 0, 0, 0, mask);

        /* 
         * Wait for other cpus to complete function or at
         * least snap the call data.
         */
        timeout = 1000000;
        while (atomic_read(&data.finished) != cpus) {
                if (--timeout <= 0)
                        goto out_timeout;
                barrier();
                udelay(1);
        }

out_unlock:
        spin_unlock(&call_lock);

        return 0;

out_timeout:
        spin_unlock(&call_lock);
        printk("XCALL: Remote cpus not responding, ncpus=%d finished=%d\n",
               cpus, atomic_read(&data.finished));
        return 0;
}

int smp_call_function(void (*func)(void *info), void *info,
                      int nonatomic, int wait)
{
        return smp_call_function_mask(func, info, nonatomic, wait,
                                      cpu_online_map);
}

void smp_call_function_client(int irq, struct pt_regs *regs)
{
        void (*func) (void *info) = call_data->func;
        void *info = call_data->info;

        clear_softint(1 << irq);
        if (call_data->wait) {
                /* let initiator proceed only after completion */
                func(info);
                atomic_inc(&call_data->finished);
        } else {
                /* let initiator proceed after getting data */
                atomic_inc(&call_data->finished);
                func(info);
        }
}

static void tsb_sync(void *info)
{
        struct mm_struct *mm = info;

        if (current->active_mm == mm)
                tsb_context_switch(mm);
}

void smp_tsb_sync(struct mm_struct *mm)
{
        smp_call_function_mask(tsb_sync, mm, 0, 1, mm->cpu_vm_mask);
}

extern unsigned long xcall_flush_tlb_mm;
extern unsigned long xcall_flush_tlb_pending;
extern unsigned long xcall_flush_tlb_kernel_range;
extern unsigned long xcall_report_regs;
extern unsigned long xcall_receive_signal;
extern unsigned long xcall_new_mmu_context_version;

#ifdef DCACHE_ALIASING_POSSIBLE
extern unsigned long xcall_flush_dcache_page_cheetah;
#endif
extern unsigned long xcall_flush_dcache_page_spitfire;

#ifdef CONFIG_DEBUG_DCFLUSH
extern atomic_t dcpage_flushes;
extern atomic_t dcpage_flushes_xcall;
#endif

static __inline__ void __local_flush_dcache_page(struct page *page)
{
#ifdef DCACHE_ALIASING_POSSIBLE
        __flush_dcache_page(page_address(page),
                            ((tlb_type == spitfire) &&
                             page_mapping(page) != NULL));
#else
        if (page_mapping(page) != NULL &&
            tlb_type == spitfire)
                __flush_icache_page(__pa(page_address(page)));
#endif
}

void smp_flush_dcache_page_impl(struct page *page, int cpu)
{
        cpumask_t mask = cpumask_of_cpu(cpu);
        int this_cpu;

        if (tlb_type == hypervisor)
                return;

#ifdef CONFIG_DEBUG_DCFLUSH
        atomic_inc(&dcpage_flushes);
#endif

        this_cpu = get_cpu();

        if (cpu == this_cpu) {
                __local_flush_dcache_page(page);
        } else if (cpu_online(cpu)) {
                void *pg_addr = page_address(page);
                u64 data0;

                if (tlb_type == spitfire) {
                        data0 =
                                ((u64)&xcall_flush_dcache_page_spitfire);
                        if (page_mapping(page) != NULL)
                                data0 |= ((u64)1 << 32);
                        spitfire_xcall_deliver(data0,
                                               __pa(pg_addr),
                                               (u64) pg_addr,
                                               mask);
                } else if (tlb_type == cheetah || tlb_type == cheetah_plus) {
#ifdef DCACHE_ALIASING_POSSIBLE
                        data0 =
                                ((u64)&xcall_flush_dcache_page_cheetah);
                        cheetah_xcall_deliver(data0,
                                              __pa(pg_addr),
                                              0, mask);
#endif
                }
#ifdef CONFIG_DEBUG_DCFLUSH
                atomic_inc(&dcpage_flushes_xcall);
#endif
        }

        put_cpu();
}

void flush_dcache_page_all(struct mm_struct *mm, struct page *page)
{
        void *pg_addr = page_address(page);
        cpumask_t mask = cpu_online_map;
        u64 data0;
        int this_cpu;

        if (tlb_type == hypervisor)
                return;

        this_cpu = get_cpu();

        cpu_clear(this_cpu, mask);

#ifdef CONFIG_DEBUG_DCFLUSH
        atomic_inc(&dcpage_flushes);
#endif
        if (cpus_empty(mask))
                goto flush_self;
        if (tlb_type == spitfire) {
                data0 = ((u64)&xcall_flush_dcache_page_spitfire);
                if (page_mapping(page) != NULL)
                        data0 |= ((u64)1 << 32);
                spitfire_xcall_deliver(data0,
                                       __pa(pg_addr),
                                       (u64) pg_addr,
                                       mask);
        } else if (tlb_type == cheetah || tlb_type == cheetah_plus) {
#ifdef DCACHE_ALIASING_POSSIBLE
                data0 = ((u64)&xcall_flush_dcache_page_cheetah);
                cheetah_xcall_deliver(data0,
                                      __pa(pg_addr),
                                      0, mask);
#endif
        }
#ifdef CONFIG_DEBUG_DCFLUSH
        atomic_inc(&dcpage_flushes_xcall);
#endif
 flush_self:
        __local_flush_dcache_page(page);

        put_cpu();
}

static void __smp_receive_signal_mask(cpumask_t mask)
{
        smp_cross_call_masked(&xcall_receive_signal, 0, 0, 0, mask);
}

void smp_receive_signal(int cpu)
{
        cpumask_t mask = cpumask_of_cpu(cpu);

        if (cpu_online(cpu))
                __smp_receive_signal_mask(mask);
}

void smp_receive_signal_client(int irq, struct pt_regs *regs)
{
        clear_softint(1 << irq);
}

void smp_new_mmu_context_version_client(int irq, struct pt_regs *regs)
{
        struct mm_struct *mm;
        unsigned long flags;

        clear_softint(1 << irq);

        /* See if we need to allocate a new TLB context because
         * the version of the one we are using is now out of date.
         */
        mm = current->active_mm;
        if (unlikely(!mm || (mm == &init_mm)))
                return;

        spin_lock_irqsave(&mm->context.lock, flags);

        if (unlikely(!CTX_VALID(mm->context)))
                get_new_mmu_context(mm);

        spin_unlock_irqrestore(&mm->context.lock, flags);

        load_secondary_context(mm);
        __flush_tlb_mm(CTX_HWBITS(mm->context),
                       SECONDARY_CONTEXT);
}

void smp_new_mmu_context_version(void)
{
        smp_cross_call(&xcall_new_mmu_context_version, 0, 0, 0);
}

void smp_report_regs(void)
{
        smp_cross_call(&xcall_report_regs, 0, 0, 0);
}

/* We know that the window frames of the user have been flushed
 * to the stack before we get here because all callers of us
 * are flush_tlb_*() routines, and these run after flush_cache_*()
 * which performs the flushw.
 *
 * The SMP TLB coherency scheme we use works as follows:
 *
 * 1) mm->cpu_vm_mask is a bit mask of which cpus an address
 *    space has (potentially) executed on, this is the heuristic
 *    we use to avoid doing cross calls.
 *
 *    Also, for flushing from kswapd and also for clones, we
 *    use cpu_vm_mask as the list of cpus to make run the TLB.
 *
 * 2) TLB context numbers are shared globally across all processors
 *    in the system, this allows us to play several games to avoid
 *    cross calls.
 *
 *    One invariant is that when a cpu switches to a process, and
 *    that processes tsk->active_mm->cpu_vm_mask does not have the
 *    current cpu's bit set, that tlb context is flushed locally.
 *
 *    If the address space is non-shared (ie. mm->count == 1) we avoid
 *    cross calls when we want to flush the currently running process's
 *    tlb state.  This is done by clearing all cpu bits except the current
 *    processor's in current->active_mm->cpu_vm_mask and performing the
 *    flush locally only.  This will force any subsequent cpus which run
 *    this task to flush the context from the local tlb if the process
 *    migrates to another cpu (again).
 *
 * 3) For shared address spaces (threads) and swapping we bite the
 *    bullet for most cases and perform the cross call (but only to
 *    the cpus listed in cpu_vm_mask).
 *
 *    The performance gain from "optimizing" away the cross call for threads is
 *    questionable (in theory the big win for threads is the massive sharing of
 *    address space state across processors).
 */

/* This currently is only used by the hugetlb arch pre-fault
 * hook on UltraSPARC-III+ and later when changing the pagesize
 * bits of the context register for an address space.
 */
void smp_flush_tlb_mm(struct mm_struct *mm)
{
        u32 ctx = CTX_HWBITS(mm->context);
        int cpu = get_cpu();

        if (atomic_read(&mm->mm_users) == 1) {
                mm->cpu_vm_mask = cpumask_of_cpu(cpu);
                goto local_flush_and_out;
        }

        smp_cross_call_masked(&xcall_flush_tlb_mm,
                              ctx, 0, 0,
                              mm->cpu_vm_mask);

local_flush_and_out:
        __flush_tlb_mm(ctx, SECONDARY_CONTEXT);

        put_cpu();
}

void smp_flush_tlb_pending(struct mm_struct *mm, unsigned long nr, unsigned long *vaddrs)
{
        u32 ctx = CTX_HWBITS(mm->context);
        int cpu = get_cpu();

        if (mm == current->active_mm && atomic_read(&mm->mm_users) == 1)
                mm->cpu_vm_mask = cpumask_of_cpu(cpu);
        else
                smp_cross_call_masked(&xcall_flush_tlb_pending,
                                      ctx, nr, (unsigned long) vaddrs,
                                      mm->cpu_vm_mask);

        __flush_tlb_pending(ctx, nr, vaddrs);

        put_cpu();
}

void smp_flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
        start &= PAGE_MASK;
        end    = PAGE_ALIGN(end);
        if (start != end) {
                smp_cross_call(&xcall_flush_tlb_kernel_range,
                               0, start, end);

                __flush_tlb_kernel_range(start, end);
        }
}

/* CPU capture. */
/* #define CAPTURE_DEBUG */
extern unsigned long xcall_capture;

static atomic_t smp_capture_depth = ATOMIC_INIT(0);
static atomic_t smp_capture_registry = ATOMIC_INIT(0);
static unsigned long penguins_are_doing_time;

void smp_capture(void)
{
        int result = atomic_add_ret(1, &smp_capture_depth);

        if (result == 1) {
                int ncpus = num_online_cpus();

#ifdef CAPTURE_DEBUG
                printk("CPU[%d]: Sending penguins to jail...",
                       smp_processor_id());
#endif
                penguins_are_doing_time = 1;
                membar_storestore_loadstore();
                atomic_inc(&smp_capture_registry);
                smp_cross_call(&xcall_capture, 0, 0, 0);
                while (atomic_read(&smp_capture_registry) != ncpus)
                        rmb();
#ifdef CAPTURE_DEBUG
                printk("done\n");
#endif
        }
}

void smp_release(void)
{
        if (atomic_dec_and_test(&smp_capture_depth)) {
#ifdef CAPTURE_DEBUG
                printk("CPU[%d]: Giving pardon to "
                       "imprisoned penguins\n",
                       smp_processor_id());
#endif
                penguins_are_doing_time = 0;
                membar_storeload_storestore();
                atomic_dec(&smp_capture_registry);
        }
}

/* Imprisoned penguins run with %pil == 15, but PSTATE_IE set, so they
 * can service tlb flush xcalls...
 */
extern void prom_world(int);

void smp_penguin_jailcell(int irq, struct pt_regs *regs)
{
        clear_softint(1 << irq);

        preempt_disable();

        __asm__ __volatile__("flushw");
        prom_world(1);
        atomic_inc(&smp_capture_registry);
        membar_storeload_storestore();
        while (penguins_are_doing_time)
                rmb();
        atomic_dec(&smp_capture_registry);
        prom_world(0);

        preempt_enable();
}

#define prof_multiplier(__cpu)          cpu_data(__cpu).multiplier
#define prof_counter(__cpu)             cpu_data(__cpu).counter

void smp_percpu_timer_interrupt(struct pt_regs *regs)
{
        unsigned long compare, tick, pstate;
        int cpu = smp_processor_id();
        int user = user_mode(regs);

        /*
         * Check for level 14 softint.
         */
        {
                unsigned long tick_mask = tick_ops->softint_mask;

                if (!(get_softint() & tick_mask)) {
                        extern void handler_irq(int, struct pt_regs *);

                        handler_irq(14, regs);
                        return;
                }
                clear_softint(tick_mask);
        }

        do {
                profile_tick(CPU_PROFILING, regs);
                if (!--prof_counter(cpu)) {
                        irq_enter();

                        if (cpu == boot_cpu_id) {
                                kstat_this_cpu.irqs[0]++;
                                timer_tick_interrupt(regs);
                        }

                        update_process_times(user);

                        irq_exit();

                        prof_counter(cpu) = prof_multiplier(cpu);
                }

                /* Guarantee that the following sequences execute
                 * uninterrupted.
                 */
                __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
                                     "wrpr      %0, %1, %%pstate"
                                     : "=r" (pstate)
                                     : "i" (PSTATE_IE));

                compare = tick_ops->add_compare(current_tick_offset);
                tick = tick_ops->get_tick();

                /* Restore PSTATE_IE. */
                __asm__ __volatile__("wrpr      %0, 0x0, %%pstate"
                                     : /* no outputs */
                                     : "r" (pstate));
        } while (time_after_eq(tick, compare));
}

static void __init smp_setup_percpu_timer(void)
{
        int cpu = smp_processor_id();
        unsigned long pstate;

        prof_counter(cpu) = prof_multiplier(cpu) = 1;

        /* Guarantee that the following sequences execute
         * uninterrupted.
         */
        __asm__ __volatile__("rdpr      %%pstate, %0\n\t"
                             "wrpr      %0, %1, %%pstate"
                             : "=r" (pstate)
                             : "i" (PSTATE_IE));

        tick_ops->init_tick(current_tick_offset);

        /* Restore PSTATE_IE. */
        __asm__ __volatile__("wrpr      %0, 0x0, %%pstate"
                             : /* no outputs */
                             : "r" (pstate));
}

void __init smp_tick_init(void)
{
        boot_cpu_id = hard_smp_processor_id();
        current_tick_offset = timer_tick_offset;

        cpu_set(boot_cpu_id, cpu_online_map);
        prof_counter(boot_cpu_id) = prof_multiplier(boot_cpu_id) = 1;
}

/* /proc/profile writes can call this, don't __init it please. */
static DEFINE_SPINLOCK(prof_setup_lock);

int setup_profiling_timer(unsigned int multiplier)
{
        unsigned long flags;
        int i;

        if ((!multiplier) || (timer_tick_offset / multiplier) < 1000)
                return -EINVAL;

        spin_lock_irqsave(&prof_setup_lock, flags);
        for (i = 0; i < NR_CPUS; i++)
                prof_multiplier(i) = multiplier;
        current_tick_offset = (timer_tick_offset / multiplier);
        spin_unlock_irqrestore(&prof_setup_lock, flags);

        return 0;
}

/* Constrain the number of cpus to max_cpus.  */
void __init smp_prepare_cpus(unsigned int max_cpus)
{
        if (num_possible_cpus() > max_cpus) {
                int instance, mid;

                instance = 0;
                while (!cpu_find_by_instance(instance, NULL, &mid)) {
                        if (mid != boot_cpu_id) {
                                cpu_clear(mid, phys_cpu_present_map);
                                if (num_possible_cpus() <= max_cpus)
                                        break;
                        }
                        instance++;
                }
        }

        smp_store_cpu_info(boot_cpu_id);
}

/* Set this up early so that things like the scheduler can init
 * properly.  We use the same cpu mask for both the present and
 * possible cpu map.
 */
void __init smp_setup_cpu_possible_map(void)
{
        int instance, mid;

        instance = 0;
        while (!cpu_find_by_instance(instance, NULL, &mid)) {
                if (mid < NR_CPUS)
                        cpu_set(mid, phys_cpu_present_map);
                instance++;
        }
}

void __devinit smp_prepare_boot_cpu(void)
{
        int cpu = hard_smp_processor_id();

        if (cpu >= NR_CPUS) {
                prom_printf("Serious problem, boot cpu id >= NR_CPUS\n");
                prom_halt();
        }

        current_thread_info()->cpu = cpu;
        __local_per_cpu_offset = __per_cpu_offset(cpu);

        cpu_set(smp_processor_id(), cpu_online_map);
        cpu_set(smp_processor_id(), phys_cpu_present_map);
}

int __devinit __cpu_up(unsigned int cpu)
{
        int ret = smp_boot_one_cpu(cpu);

        if (!ret) {
                cpu_set(cpu, smp_commenced_mask);
                while (!cpu_isset(cpu, cpu_online_map))
                        mb();
                if (!cpu_isset(cpu, cpu_online_map)) {
                        ret = -ENODEV;
                } else {
                        /* On SUN4V, writes to %tick and %stick are
                         * not allowed.
                         */
                        if (tlb_type != hypervisor)
                                smp_synchronize_one_tick(cpu);
                }
        }
        return ret;
}

void __init smp_cpus_done(unsigned int max_cpus)
{
        unsigned long bogosum = 0;
        int i;

        for (i = 0; i < NR_CPUS; i++) {
                if (cpu_online(i))
                        bogosum += cpu_data(i).udelay_val;
        }
        printk("Total of %ld processors activated "
               "(%lu.%02lu BogoMIPS).\n",
               (long) num_online_cpus(),
               bogosum/(500000/HZ),
               (bogosum/(5000/HZ))%100);
}

void smp_send_reschedule(int cpu)
{
        smp_receive_signal(cpu);
}

/* This is a nop because we capture all other cpus
 * anyways when making the PROM active.
 */
void smp_send_stop(void)
{
}

unsigned long __per_cpu_base __read_mostly;
unsigned long __per_cpu_shift __read_mostly;

EXPORT_SYMBOL(__per_cpu_base);
EXPORT_SYMBOL(__per_cpu_shift);

void __init setup_per_cpu_areas(void)
{
        unsigned long goal, size, i;
        char *ptr;

        /* Copy section for each CPU (we discard the original) */
        goal = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
#ifdef CONFIG_MODULES
        if (goal < PERCPU_ENOUGH_ROOM)
                goal = PERCPU_ENOUGH_ROOM;
#endif
        __per_cpu_shift = 0;
        for (size = 1UL; size < goal; size <<= 1UL)
                __per_cpu_shift++;

        ptr = alloc_bootmem(size * NR_CPUS);

        __per_cpu_base = ptr - __per_cpu_start;

        for (i = 0; i < NR_CPUS; i++, ptr += size)
                memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
}