Linux 4.8-rc8

[linux/fpc-iii.git] / arch / sparc / kernel / smp_64.c

/* smp.c: Sparc64 SMP support.
 *
 * Copyright (C) 1997, 2007, 2008 David S. Miller (davem@davemloft.net)
 */

#include <linux/export.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/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 <linux/vmalloc.h>
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <linux/slab.h>
#include <linux/kgdb.h>

#include <asm/head.h>
#include <asm/ptrace.h>
#include <linux/atomic.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/cpudata.h>
#include <asm/hvtramp.h>
#include <asm/io.h>
#include <asm/timer.h>
#include <asm/setup.h>

#include <asm/irq.h>
#include <asm/irq_regs.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/oplib.h>
#include <asm/uaccess.h>
#include <asm/starfire.h>
#include <asm/tlb.h>
#include <asm/sections.h>
#include <asm/prom.h>
#include <asm/mdesc.h>
#include <asm/ldc.h>
#include <asm/hypervisor.h>
#include <asm/pcr.h>

#include "cpumap.h"
#include "kernel.h"

DEFINE_PER_CPU(cpumask_t, cpu_sibling_map) = CPU_MASK_NONE;
cpumask_t cpu_core_map[NR_CPUS] __read_mostly =
        { [0 ... NR_CPUS-1] = CPU_MASK_NONE };

cpumask_t cpu_core_sib_map[NR_CPUS] __read_mostly = {
        [0 ... NR_CPUS-1] = CPU_MASK_NONE };

EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
EXPORT_SYMBOL(cpu_core_map);
EXPORT_SYMBOL(cpu_core_sib_map);

static cpumask_t smp_commenced_mask;

void smp_info(struct seq_file *m)
{
        int i;
        
        seq_printf(m, "State:\n");
        for_each_online_cpu(i)
                seq_printf(m, "CPU%d:\t\tonline\n", i);
}

void smp_bogo(struct seq_file *m)
{
        int i;
        
        for_each_online_cpu(i)
                seq_printf(m,
                           "Cpu%dClkTck\t: %016lx\n",
                           i, cpu_data(i).clock_tick);
}

extern void setup_sparc64_timer(void);

static volatile unsigned long callin_flag = 0;

void 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();

        setup_sparc64_timer();

        if (cheetah_pcache_forced_on)
                cheetah_enable_pcache();

        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;

        /* inform the notifiers about the new cpu */
        notify_cpu_starting(cpuid);

        while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
                rmb();

        set_cpu_online(cpuid, true);

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

        local_irq_enable();

        cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}

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

/* 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_RAW_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_safe("#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;
#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... */

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

                                tick_ops->add_tick(adj);
                        }
#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_safe("#StoreLoad");

        raw_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_safe("#StoreLoad");
                }
        }
        raw_spin_unlock_irqrestore(&itc_sync_lock, flags);
}

#if defined(CONFIG_SUN_LDOMS) && defined(CONFIG_HOTPLUG_CPU)
static void ldom_startcpu_cpuid(unsigned int cpu, unsigned long thread_reg,
                                void **descrp)
{
        extern unsigned long sparc64_ttable_tl0;
        extern unsigned long kern_locked_tte_data;
        struct hvtramp_descr *hdesc;
        unsigned long trampoline_ra;
        struct trap_per_cpu *tb;
        u64 tte_vaddr, tte_data;
        unsigned long hv_err;
        int i;

        hdesc = kzalloc(sizeof(*hdesc) +
                        (sizeof(struct hvtramp_mapping) *
                         num_kernel_image_mappings - 1),
                        GFP_KERNEL);
        if (!hdesc) {
                printk(KERN_ERR "ldom_startcpu_cpuid: Cannot allocate "
                       "hvtramp_descr.\n");
                return;
        }
        *descrp = hdesc;

        hdesc->cpu = cpu;
        hdesc->num_mappings = num_kernel_image_mappings;

        tb = &trap_block[cpu];

        hdesc->fault_info_va = (unsigned long) &tb->fault_info;
        hdesc->fault_info_pa = kimage_addr_to_ra(&tb->fault_info);

        hdesc->thread_reg = thread_reg;

        tte_vaddr = (unsigned long) KERNBASE;
        tte_data = kern_locked_tte_data;

        for (i = 0; i < hdesc->num_mappings; i++) {
                hdesc->maps[i].vaddr = tte_vaddr;
                hdesc->maps[i].tte   = tte_data;
                tte_vaddr += 0x400000;
                tte_data  += 0x400000;
        }

        trampoline_ra = kimage_addr_to_ra(hv_cpu_startup);

        hv_err = sun4v_cpu_start(cpu, trampoline_ra,
                                 kimage_addr_to_ra(&sparc64_ttable_tl0),
                                 __pa(hdesc));
        if (hv_err)
                printk(KERN_ERR "ldom_startcpu_cpuid: sun4v_cpu_start() "
                       "gives error %lu\n", hv_err);
}
#endif

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 smp_boot_one_cpu(unsigned int cpu, struct task_struct *idle)
{
        unsigned long entry =
                (unsigned long)(&sparc64_cpu_startup);
        unsigned long cookie =
                (unsigned long)(&cpu_new_thread);
        void *descr = NULL;
        int timeout, ret;

        callin_flag = 0;
        cpu_new_thread = task_thread_info(idle);

        if (tlb_type == hypervisor) {
#if defined(CONFIG_SUN_LDOMS) && defined(CONFIG_HOTPLUG_CPU)
                if (ldom_domaining_enabled)
                        ldom_startcpu_cpuid(cpu,
                                            (unsigned long) cpu_new_thread,
                                            &descr);
                else
#endif
                        prom_startcpu_cpuid(cpu, entry, cookie);
        } else {
                struct device_node *dp = of_find_node_by_cpuid(cpu);

                prom_startcpu(dp->phandle, entry, cookie);
        }

        for (timeout = 0; timeout < 50000; timeout++) {
                if (callin_flag)
                        break;
                udelay(100);
        }

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

        kfree(descr);

        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[%016llx]\n",
                       smp_processor_id(), result);
        } else {
                udelay(2);
                goto again;
        }
}

static void spitfire_xcall_deliver(struct trap_per_cpu *tb, int cnt)
{
        u64 *mondo, data0, data1, data2;
        u16 *cpu_list;
        u64 pstate;
        int i;

        __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate));
        cpu_list = __va(tb->cpu_list_pa);
        mondo = __va(tb->cpu_mondo_block_pa);
        data0 = mondo[0];
        data1 = mondo[1];
        data2 = mondo[2];
        for (i = 0; i < cnt; i++)
                spitfire_xcall_helper(data0, data1, data2, pstate, cpu_list[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(struct trap_per_cpu *tb, int cnt)
{
        int nack_busy_id, is_jbus, need_more;
        u64 *mondo, pstate, ver, busy_mask;
        u16 *cpu_list;

        cpu_list = __va(tb->cpu_list_pa);
        mondo = __va(tb->cpu_mondo_block_pa);

        /* 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:
        need_more = 0;
        __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" (mondo[0]), "r" (mondo[1]), "r" (mondo[2]),
                               "r" (0x40), "r" (0x50), "r" (0x60),
                               "i" (ASI_INTR_W));

        nack_busy_id = 0;
        busy_mask = 0;
        {
                int i;

                for (i = 0; i < cnt; i++) {
                        u64 target, nr;

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

                        target = (nr << 14) | 0x70;
                        if (is_jbus) {
                                busy_mask |= (0x1UL << (nr * 2));
                        } else {
                                target |= (nack_busy_id << 24);
                                busy_mask |= (0x1UL <<
                                              (nack_busy_id * 2));
                        }
                        __asm__ __volatile__(
                                "stxa   %%g0, [%0] %1\n\t"
                                "membar #Sync\n\t"
                                : /* no outputs */
                                : "r" (target), "i" (ASI_INTR_W));
                        nack_busy_id++;
                        if (nack_busy_id == 32) {
                                need_more = 1;
                                break;
                        }
                }
        }

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

                stuck = 100000 * nack_busy_id;
                nack_mask = busy_mask << 1;
                do {
                        __asm__ __volatile__("ldxa      [%%g0] %1, %0"
                                             : "=r" (dispatch_stat)
                                             : "i" (ASI_INTR_DISPATCH_STAT));
                        if (!(dispatch_stat & (busy_mask | nack_mask))) {
                                __asm__ __volatile__("wrpr %0, 0x0, %%pstate"
                                                     : : "r" (pstate));
                                if (unlikely(need_more)) {
                                        int i, this_cnt = 0;
                                        for (i = 0; i < cnt; i++) {
                                                if (cpu_list[i] == 0xffff)
                                                        continue;
                                                cpu_list[i] = 0xffff;
                                                this_cnt++;
                                                if (this_cnt == 32)
                                                        break;
                                        }
                                        goto retry;
                                }
                                return;
                        }
                        if (!--stuck)
                                break;
                } while (dispatch_stat & busy_mask);

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

                if (dispatch_stat & busy_mask) {
                        /* Busy bits will not clear, continue instead
                         * of freezing up on this cpu.
                         */
                        printk("CPU[%d]: mondo stuckage result[%016llx]\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 (i = 0; i < cnt; i++) {
                                u64 check_mask, nr;

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

                                if (is_jbus)
                                        check_mask = (0x2UL << (2*nr));
                                else
                                        check_mask = (0x2UL <<
                                                      this_busy_nack);
                                if ((dispatch_stat & check_mask) == 0)
                                        cpu_list[i] = 0xffff;
                                this_busy_nack += 2;
                                if (this_busy_nack == 64)
                                        break;
                        }

                        goto retry;
                }
        }
}

/* Multi-cpu list version.  */
static void hypervisor_xcall_deliver(struct trap_per_cpu *tb, int cnt)
{
        int retries, this_cpu, prev_sent, i, saw_cpu_error;
        unsigned long status;
        u16 *cpu_list;

        this_cpu = smp_processor_id();

        cpu_list = __va(tb->cpu_list_pa);

        saw_cpu_error = 0;
        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 == HV_CPU_STATE_ERROR) {
                                        saw_cpu_error = (cpu + 1);
                                        cpu_list[i] = 0xffff;
                                }
                        }
                } 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);

        if (unlikely(saw_cpu_error))
                goto fatal_mondo_cpu_error;

        return;

fatal_mondo_cpu_error:
        printk(KERN_CRIT "CPU[%d]: SUN4V mondo cpu error, some target cpus "
               "(including %d) were in error state\n",
               this_cpu, saw_cpu_error - 1);
        return;

fatal_mondo_timeout:
        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:
        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");
}

static void (*xcall_deliver_impl)(struct trap_per_cpu *, int);

static void xcall_deliver(u64 data0, u64 data1, u64 data2, const cpumask_t *mask)
{
        struct trap_per_cpu *tb;
        int this_cpu, i, cnt;
        unsigned long flags;
        u16 *cpu_list;
        u64 *mondo;

        /* 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(i, mask) {
                if (i == this_cpu || !cpu_online(i))
                        continue;
                cpu_list[cnt++] = i;
        }

        if (cnt)
                xcall_deliver_impl(tb, cnt);

        local_irq_restore(flags);
}

/* Send cross call to all processors mentioned in MASK_P
 * except self.  Really, there are only two cases currently,
 * "cpu_online_mask" and "mm_cpumask(mm)".
 */
static void smp_cross_call_masked(unsigned long *func, u32 ctx, u64 data1, u64 data2, const cpumask_t *mask)
{
        u64 data0 = (((u64)ctx)<<32 | (((u64)func) & 0xffffffff));

        xcall_deliver(data0, data1, data2, mask);
}

/* Send cross call to all processors except self. */
static void smp_cross_call(unsigned long *func, u32 ctx, u64 data1, u64 data2)
{
        smp_cross_call_masked(func, ctx, data1, data2, cpu_online_mask);
}

extern unsigned long xcall_sync_tick;

static void smp_start_sync_tick_client(int cpu)
{
        xcall_deliver((u64) &xcall_sync_tick, 0, 0,
                      cpumask_of(cpu));
}

extern unsigned long xcall_call_function;

void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
        xcall_deliver((u64) &xcall_call_function, 0, 0, mask);
}

extern unsigned long xcall_call_function_single;

void arch_send_call_function_single_ipi(int cpu)
{
        xcall_deliver((u64) &xcall_call_function_single, 0, 0,
                      cpumask_of(cpu));
}

void __irq_entry smp_call_function_client(int irq, struct pt_regs *regs)
{
        clear_softint(1 << irq);
        irq_enter();
        generic_smp_call_function_interrupt();
        irq_exit();
}

void __irq_entry smp_call_function_single_client(int irq, struct pt_regs *regs)
{
        clear_softint(1 << irq);
        irq_enter();
        generic_smp_call_function_single_interrupt();
        irq_exit();
}

static void tsb_sync(void *info)
{
        struct trap_per_cpu *tp = &trap_block[raw_smp_processor_id()];
        struct mm_struct *mm = info;

        /* It is not valid to test "current->active_mm == mm" here.
         *
         * The value of "current" is not changed atomically with
         * switch_mm().  But that's OK, we just need to check the
         * current cpu's trap block PGD physical address.
         */
        if (tp->pgd_paddr == __pa(mm->pgd))
                tsb_context_switch(mm);
}

void smp_tsb_sync(struct mm_struct *mm)
{
        smp_call_function_many(mm_cpumask(mm), tsb_sync, mm, 1);
}

extern unsigned long xcall_flush_tlb_mm;
extern unsigned long xcall_flush_tlb_page;
extern unsigned long xcall_flush_tlb_kernel_range;
extern unsigned long xcall_fetch_glob_regs;
extern unsigned long xcall_fetch_glob_pmu;
extern unsigned long xcall_fetch_glob_pmu_n4;
extern unsigned long xcall_receive_signal;
extern unsigned long xcall_new_mmu_context_version;
#ifdef CONFIG_KGDB
extern unsigned long xcall_kgdb_capture;
#endif

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

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)
{
        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 = 0;

                if (tlb_type == spitfire) {
                        data0 = ((u64)&xcall_flush_dcache_page_spitfire);
                        if (page_mapping(page) != NULL)
                                data0 |= ((u64)1 << 32);
                } else if (tlb_type == cheetah || tlb_type == cheetah_plus) {
#ifdef DCACHE_ALIASING_POSSIBLE
                        data0 = ((u64)&xcall_flush_dcache_page_cheetah);
#endif
                }
                if (data0) {
                        xcall_deliver(data0, __pa(pg_addr),
                                      (u64) pg_addr, cpumask_of(cpu));
#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;
        u64 data0;

        if (tlb_type == hypervisor)
                return;

        preempt_disable();

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

        preempt_enable();
}

void __irq_entry 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);
}

#ifdef CONFIG_KGDB
void kgdb_roundup_cpus(unsigned long flags)
{
        smp_cross_call(&xcall_kgdb_capture, 0, 0, 0);
}
#endif

void smp_fetch_global_regs(void)
{
        smp_cross_call(&xcall_fetch_glob_regs, 0, 0, 0);
}

void smp_fetch_global_pmu(void)
{
        if (tlb_type == hypervisor &&
            sun4v_chip_type >= SUN4V_CHIP_NIAGARA4)
                smp_cross_call(&xcall_fetch_glob_pmu_n4, 0, 0, 0);
        else
                smp_cross_call(&xcall_fetch_glob_pmu, 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->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) {
                cpumask_copy(mm_cpumask(mm), cpumask_of(cpu));
                goto local_flush_and_out;
        }

        smp_cross_call_masked(&xcall_flush_tlb_mm,
                              ctx, 0, 0,
                              mm_cpumask(mm));

local_flush_and_out:
        __flush_tlb_mm(ctx, SECONDARY_CONTEXT);

        put_cpu();
}

struct tlb_pending_info {
        unsigned long ctx;
        unsigned long nr;
        unsigned long *vaddrs;
};

static void tlb_pending_func(void *info)
{
        struct tlb_pending_info *t = info;

        __flush_tlb_pending(t->ctx, t->nr, t->vaddrs);
}

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

        info.ctx = ctx;
        info.nr = nr;
        info.vaddrs = vaddrs;

        if (mm == current->mm && atomic_read(&mm->mm_users) == 1)
                cpumask_copy(mm_cpumask(mm), cpumask_of(cpu));
        else
                smp_call_function_many(mm_cpumask(mm), tlb_pending_func,
                                       &info, 1);

        __flush_tlb_pending(ctx, nr, vaddrs);

        put_cpu();
}

void smp_flush_tlb_page(struct mm_struct *mm, unsigned long vaddr)
{
        unsigned long context = CTX_HWBITS(mm->context);
        int cpu = get_cpu();

        if (mm == current->mm && atomic_read(&mm->mm_users) == 1)
                cpumask_copy(mm_cpumask(mm), cpumask_of(cpu));
        else
                smp_cross_call_masked(&xcall_flush_tlb_page,
                                      context, vaddr, 0,
                                      mm_cpumask(mm));
        __flush_tlb_page(context, vaddr);

        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_return(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;
                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_safe("#StoreLoad");
                atomic_dec(&smp_capture_registry);
        }
}

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

void __irq_entry 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_safe("#StoreLoad");
        while (penguins_are_doing_time)
                rmb();
        atomic_dec(&smp_capture_registry);
        prom_world(0);

        preempt_enable();
}

/* /proc/profile writes can call this, don't __init it please. */
int setup_profiling_timer(unsigned int multiplier)
{
        return -EINVAL;
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
}

void smp_prepare_boot_cpu(void)
{
}

void __init smp_setup_processor_id(void)
{
        if (tlb_type == spitfire)
                xcall_deliver_impl = spitfire_xcall_deliver;
        else if (tlb_type == cheetah || tlb_type == cheetah_plus)
                xcall_deliver_impl = cheetah_xcall_deliver;
        else
                xcall_deliver_impl = hypervisor_xcall_deliver;
}

void smp_fill_in_sib_core_maps(void)
{
        unsigned int i;

        for_each_present_cpu(i) {
                unsigned int j;

                cpumask_clear(&cpu_core_map[i]);
                if (cpu_data(i).core_id == 0) {
                        cpumask_set_cpu(i, &cpu_core_map[i]);
                        continue;
                }

                for_each_present_cpu(j) {
                        if (cpu_data(i).core_id ==
                            cpu_data(j).core_id)
                                cpumask_set_cpu(j, &cpu_core_map[i]);
                }
        }

        for_each_present_cpu(i)  {
                unsigned int j;

                for_each_present_cpu(j)  {
                        if (cpu_data(i).sock_id == cpu_data(j).sock_id)
                                cpumask_set_cpu(j, &cpu_core_sib_map[i]);
                }
        }

        for_each_present_cpu(i) {
                unsigned int j;

                cpumask_clear(&per_cpu(cpu_sibling_map, i));
                if (cpu_data(i).proc_id == -1) {
                        cpumask_set_cpu(i, &per_cpu(cpu_sibling_map, i));
                        continue;
                }

                for_each_present_cpu(j) {
                        if (cpu_data(i).proc_id ==
                            cpu_data(j).proc_id)
                                cpumask_set_cpu(j, &per_cpu(cpu_sibling_map, i));
                }
        }
}

int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
        int ret = smp_boot_one_cpu(cpu, tidle);

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

#ifdef CONFIG_HOTPLUG_CPU
void cpu_play_dead(void)
{
        int cpu = smp_processor_id();
        unsigned long pstate;

        idle_task_exit();

        if (tlb_type == hypervisor) {
                struct trap_per_cpu *tb = &trap_block[cpu];

                sun4v_cpu_qconf(HV_CPU_QUEUE_CPU_MONDO,
                                tb->cpu_mondo_pa, 0);
                sun4v_cpu_qconf(HV_CPU_QUEUE_DEVICE_MONDO,
                                tb->dev_mondo_pa, 0);
                sun4v_cpu_qconf(HV_CPU_QUEUE_RES_ERROR,
                                tb->resum_mondo_pa, 0);
                sun4v_cpu_qconf(HV_CPU_QUEUE_NONRES_ERROR,
                                tb->nonresum_mondo_pa, 0);
        }

        cpumask_clear_cpu(cpu, &smp_commenced_mask);
        membar_safe("#Sync");

        local_irq_disable();

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

        while (1)
                barrier();
}

int __cpu_disable(void)
{
        int cpu = smp_processor_id();
        cpuinfo_sparc *c;
        int i;

        for_each_cpu(i, &cpu_core_map[cpu])
                cpumask_clear_cpu(cpu, &cpu_core_map[i]);
        cpumask_clear(&cpu_core_map[cpu]);

        for_each_cpu(i, &per_cpu(cpu_sibling_map, cpu))
                cpumask_clear_cpu(cpu, &per_cpu(cpu_sibling_map, i));
        cpumask_clear(&per_cpu(cpu_sibling_map, cpu));

        c = &cpu_data(cpu);

        c->core_id = 0;
        c->proc_id = -1;

        smp_wmb();

        /* Make sure no interrupts point to this cpu.  */
        fixup_irqs();

        local_irq_enable();
        mdelay(1);
        local_irq_disable();

        set_cpu_online(cpu, false);

        cpu_map_rebuild();

        return 0;
}

void __cpu_die(unsigned int cpu)
{
        int i;

        for (i = 0; i < 100; i++) {
                smp_rmb();
                if (!cpumask_test_cpu(cpu, &smp_commenced_mask))
                        break;
                msleep(100);
        }
        if (cpumask_test_cpu(cpu, &smp_commenced_mask)) {
                printk(KERN_ERR "CPU %u didn't die...\n", cpu);
        } else {
#if defined(CONFIG_SUN_LDOMS)
                unsigned long hv_err;
                int limit = 100;

                do {
                        hv_err = sun4v_cpu_stop(cpu);
                        if (hv_err == HV_EOK) {
                                set_cpu_present(cpu, false);
                                break;
                        }
                } while (--limit > 0);
                if (limit <= 0) {
                        printk(KERN_ERR "sun4v_cpu_stop() fails err=%lu\n",
                               hv_err);
                }
#endif
        }
}
#endif

void __init smp_cpus_done(unsigned int max_cpus)
{
}

void smp_send_reschedule(int cpu)
{
        if (cpu == smp_processor_id()) {
                WARN_ON_ONCE(preemptible());
                set_softint(1 << PIL_SMP_RECEIVE_SIGNAL);
        } else {
                xcall_deliver((u64) &xcall_receive_signal,
                              0, 0, cpumask_of(cpu));
        }
}

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

static void stop_this_cpu(void *dummy)
{
        prom_stopself();
}

void smp_send_stop(void)
{
        int cpu;

        if (tlb_type == hypervisor) {
                for_each_online_cpu(cpu) {
                        if (cpu == smp_processor_id())
                                continue;
#ifdef CONFIG_SUN_LDOMS
                        if (ldom_domaining_enabled) {
                                unsigned long hv_err;
                                hv_err = sun4v_cpu_stop(cpu);
                                if (hv_err)
                                        printk(KERN_ERR "sun4v_cpu_stop() "
                                               "failed err=%lu\n", hv_err);
                        } else
#endif
                                prom_stopcpu_cpuid(cpu);
                }
        } else
                smp_call_function(stop_this_cpu, NULL, 0);
}

/**
 * pcpu_alloc_bootmem - NUMA friendly alloc_bootmem wrapper for percpu
 * @cpu: cpu to allocate for
 * @size: size allocation in bytes
 * @align: alignment
 *
 * Allocate @size bytes aligned at @align for cpu @cpu.  This wrapper
 * does the right thing for NUMA regardless of the current
 * configuration.
 *
 * RETURNS:
 * Pointer to the allocated area on success, NULL on failure.
 */
static void * __init pcpu_alloc_bootmem(unsigned int cpu, size_t size,
                                        size_t align)
{
        const unsigned long goal = __pa(MAX_DMA_ADDRESS);
#ifdef CONFIG_NEED_MULTIPLE_NODES
        int node = cpu_to_node(cpu);
        void *ptr;

        if (!node_online(node) || !NODE_DATA(node)) {
                ptr = __alloc_bootmem(size, align, goal);
                pr_info("cpu %d has no node %d or node-local memory\n",
                        cpu, node);
                pr_debug("per cpu data for cpu%d %lu bytes at %016lx\n",
                         cpu, size, __pa(ptr));
        } else {
                ptr = __alloc_bootmem_node(NODE_DATA(node),
                                           size, align, goal);
                pr_debug("per cpu data for cpu%d %lu bytes on node%d at "
                         "%016lx\n", cpu, size, node, __pa(ptr));
        }
        return ptr;
#else
        return __alloc_bootmem(size, align, goal);
#endif
}

static void __init pcpu_free_bootmem(void *ptr, size_t size)
{
        free_bootmem(__pa(ptr), size);
}

static int __init pcpu_cpu_distance(unsigned int from, unsigned int to)
{
        if (cpu_to_node(from) == cpu_to_node(to))
                return LOCAL_DISTANCE;
        else
                return REMOTE_DISTANCE;
}

static void __init pcpu_populate_pte(unsigned long addr)
{
        pgd_t *pgd = pgd_offset_k(addr);
        pud_t *pud;
        pmd_t *pmd;

        if (pgd_none(*pgd)) {
                pud_t *new;

                new = __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, PAGE_SIZE);
                pgd_populate(&init_mm, pgd, new);
        }

        pud = pud_offset(pgd, addr);
        if (pud_none(*pud)) {
                pmd_t *new;

                new = __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, PAGE_SIZE);
                pud_populate(&init_mm, pud, new);
        }

        pmd = pmd_offset(pud, addr);
        if (!pmd_present(*pmd)) {
                pte_t *new;

                new = __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, PAGE_SIZE);
                pmd_populate_kernel(&init_mm, pmd, new);
        }
}

void __init setup_per_cpu_areas(void)
{
        unsigned long delta;
        unsigned int cpu;
        int rc = -EINVAL;

        if (pcpu_chosen_fc != PCPU_FC_PAGE) {
                rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE,
                                            PERCPU_DYNAMIC_RESERVE, 4 << 20,
                                            pcpu_cpu_distance,
                                            pcpu_alloc_bootmem,
                                            pcpu_free_bootmem);
                if (rc)
                        pr_warning("PERCPU: %s allocator failed (%d), "
                                   "falling back to page size\n",
                                   pcpu_fc_names[pcpu_chosen_fc], rc);
        }
        if (rc < 0)
                rc = pcpu_page_first_chunk(PERCPU_MODULE_RESERVE,
                                           pcpu_alloc_bootmem,
                                           pcpu_free_bootmem,
                                           pcpu_populate_pte);
        if (rc < 0)
                panic("cannot initialize percpu area (err=%d)", rc);

        delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
        for_each_possible_cpu(cpu)
                __per_cpu_offset(cpu) = delta + pcpu_unit_offsets[cpu];

        /* Setup %g5 for the boot cpu.  */
        __local_per_cpu_offset = __per_cpu_offset(smp_processor_id());

        of_fill_in_cpu_data();
        if (tlb_type == hypervisor)
                mdesc_fill_in_cpu_data(cpu_all_mask);
}