// SPDX-License-Identifier: GPL-2.0
/* 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/mm.h>
#include <linux/sched/hotplug.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/memblock.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/oplib.h>
#include <linux/uaccess.h>
#include <asm/starfire.h>
#include <asm/tlb.h>
#include <asm/pgalloc.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 };

cpumask_t cpu_core_sib_cache_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);
EXPORT_SYMBOL(cpu_core_sib_cache_map);

static cpumask_t smp_commenced_mask;

static DEFINE_PER_CPU(bool, poke);
static bool cpu_poke;

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. */
        mmgrab(&init_mm);
        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);

        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_flex(*hdesc, maps, num_kernel_image_mappings);
        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;
                }
        }
}

#define CPU_MONDO_COUNTER(cpuid)        (cpu_mondo_counter[cpuid])
#define MONDO_USEC_WAIT_MIN             2
#define MONDO_USEC_WAIT_MAX             100
#define MONDO_RETRY_LIMIT               500000

/* Multi-cpu list version.
 *
 * Deliver xcalls to 'cnt' number of cpus in 'cpu_list'.
 * Sometimes not all cpus receive the mondo, requiring us to re-send
 * the mondo until all cpus have received, or cpus are truly stuck
 * unable to receive mondo, and we timeout.
 * Occasionally a target cpu strand is borrowed briefly by hypervisor to
 * perform guest service, such as PCIe error handling. Consider the
 * service time, 1 second overall wait is reasonable for 1 cpu.
 * Here two in-between mondo check wait time are defined: 2 usec for
 * single cpu quick turn around and up to 100usec for large cpu count.
 * Deliver mondo to large number of cpus could take longer, we adjusts
 * the retry count as long as target cpus are making forward progress.
 */
static void hypervisor_xcall_deliver(struct trap_per_cpu *tb, int cnt)
{
        int this_cpu, tot_cpus, prev_sent, i, rem;
        int usec_wait, retries, tot_retries;
        u16 first_cpu = 0xffff;
        unsigned long xc_rcvd = 0;
        unsigned long status;
        int ecpuerror_id = 0;
        int enocpu_id = 0;
        u16 *cpu_list;
        u16 cpu;

        this_cpu = smp_processor_id();
        cpu_list = __va(tb->cpu_list_pa);
        usec_wait = cnt * MONDO_USEC_WAIT_MIN;
        if (usec_wait > MONDO_USEC_WAIT_MAX)
                usec_wait = MONDO_USEC_WAIT_MAX;
        retries = tot_retries = 0;
        tot_cpus = cnt;
        prev_sent = 0;

        do {
                int n_sent, mondo_delivered, target_cpu_busy;

                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))
                        goto xcall_done;

                /* If not these non-fatal errors, panic */
                if (unlikely((status != HV_EWOULDBLOCK) &&
                        (status != HV_ECPUERROR) &&
                        (status != HV_ENOCPU)))
                        goto fatal_errors;

                /* First, see if we made any forward progress.
                 *
                 * Go through the cpu_list, count the target cpus that have
                 * received our mondo (n_sent), and those that did not (rem).
                 * Re-pack cpu_list with the cpus remain to be retried in the
                 * front - this simplifies tracking the truly stalled cpus.
                 *
                 * The hypervisor indicates successful sends by setting
                 * cpu list entries to the value 0xffff.
                 *
                 * EWOULDBLOCK means some target cpus did not receive the
                 * mondo and retry usually helps.
                 *
                 * ECPUERROR means at least one target cpu is in error state,
                 * it's usually safe to skip the faulty cpu and retry.
                 *
                 * ENOCPU means one of the target cpu doesn't belong to the
                 * domain, perhaps offlined which is unexpected, but not
                 * fatal and it's okay to skip the offlined cpu.
                 */
                rem = 0;
                n_sent = 0;
                for (i = 0; i < cnt; i++) {
                        cpu = cpu_list[i];
                        if (likely(cpu == 0xffff)) {
                                n_sent++;
                        } else if ((status == HV_ECPUERROR) &&
                                (sun4v_cpu_state(cpu) == HV_CPU_STATE_ERROR)) {
                                ecpuerror_id = cpu + 1;
                        } else if (status == HV_ENOCPU && !cpu_online(cpu)) {
                                enocpu_id = cpu + 1;
                        } else {
                                cpu_list[rem++] = cpu;
                        }
                }

                /* No cpu remained, we're done. */
                if (rem == 0)
                        break;

                /* Otherwise, update the cpu count for retry. */
                cnt = rem;

                /* Record the overall number of mondos received by the
                 * first of the remaining cpus.
                 */
                if (first_cpu != cpu_list[0]) {
                        first_cpu = cpu_list[0];
                        xc_rcvd = CPU_MONDO_COUNTER(first_cpu);
                }

                /* Was any mondo delivered successfully? */
                mondo_delivered = (n_sent > prev_sent);
                prev_sent = n_sent;

                /* or, was any target cpu busy processing other mondos? */
                target_cpu_busy = (xc_rcvd < CPU_MONDO_COUNTER(first_cpu));
                xc_rcvd = CPU_MONDO_COUNTER(first_cpu);

                /* Retry count is for no progress. If we're making progress,
                 * reset the retry count.
                 */
                if (likely(mondo_delivered || target_cpu_busy)) {
                        tot_retries += retries;
                        retries = 0;
                } else if (unlikely(retries > MONDO_RETRY_LIMIT)) {
                        goto fatal_mondo_timeout;
                }

                /* Delay a little bit to let other cpus catch up on
                 * their cpu mondo queue work.
                 */
                if (!mondo_delivered)
                        udelay(usec_wait);

                retries++;
        } while (1);

xcall_done:
        if (unlikely(ecpuerror_id > 0)) {
                pr_crit("CPU[%d]: SUN4V mondo cpu error, target cpu(%d) was in error state\n",
                       this_cpu, ecpuerror_id - 1);
        } else if (unlikely(enocpu_id > 0)) {
                pr_crit("CPU[%d]: SUN4V mondo cpu error, target cpu(%d) does not belong to the domain\n",
                       this_cpu, enocpu_id - 1);
        }
        return;

fatal_errors:
        /* fatal errors include bad alignment, etc */
        pr_crit("CPU[%d]: Args were cnt(%d) cpulist_pa(%lx) mondo_block_pa(%lx)\n",
               this_cpu, tot_cpus, tb->cpu_list_pa, tb->cpu_mondo_block_pa);
        panic("Unexpected SUN4V mondo error %lu\n", status);

fatal_mondo_timeout:
        /* some cpus being non-responsive to the cpu mondo */
        pr_crit("CPU[%d]: SUN4V mondo timeout, cpu(%d) made no forward progress after %d retries. Total target cpus(%d).\n",
               this_cpu, first_cpu, (tot_retries + retries), tot_cpus);
        panic("SUN4V mondo timeout panic\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_folio(struct folio *folio)
{
        unsigned int i, nr = folio_nr_pages(folio);

#ifdef DCACHE_ALIASING_POSSIBLE
        for (i = 0; i < nr; i++)
                __flush_dcache_page(folio_address(folio) + i * PAGE_SIZE,
                            ((tlb_type == spitfire) &&
                             folio_flush_mapping(folio) != NULL));
#else
        if (folio_flush_mapping(folio) != NULL &&
            tlb_type == spitfire) {
                unsigned long pfn = folio_pfn(folio)
                for (i = 0; i < nr; i++)
                        __flush_icache_page((pfn + i) * PAGE_SIZE);
        }
#endif
}

void smp_flush_dcache_folio_impl(struct folio *folio, 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_folio(folio);
        } else if (cpu_online(cpu)) {
                void *pg_addr = folio_address(folio);
                u64 data0 = 0;

                if (tlb_type == spitfire) {
                        data0 = ((u64)&xcall_flush_dcache_page_spitfire);
                        if (folio_flush_mapping(folio) != 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) {
                        unsigned int i, nr = folio_nr_pages(folio);

                        for (i = 0; i < nr; i++) {
                                xcall_deliver(data0, __pa(pg_addr),
                                              (u64) pg_addr, cpumask_of(cpu));
#ifdef CONFIG_DEBUG_DCFLUSH
                                atomic_inc(&dcpage_flushes_xcall);
#endif
                                pg_addr += PAGE_SIZE;
                        }
                }
        }

        put_cpu();
}

void flush_dcache_folio_all(struct mm_struct *mm, struct folio *folio)
{
        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 = folio_address(folio);
        if (tlb_type == spitfire) {
                data0 = ((u64)&xcall_flush_dcache_page_spitfire);
                if (folio_flush_mapping(folio) != 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) {
                unsigned int i, nr = folio_nr_pages(folio);

                for (i = 0; i < nr; i++) {
                        xcall_deliver(data0, __pa(pg_addr),
                                      (u64) pg_addr, cpu_online_mask);
#ifdef CONFIG_DEBUG_DCFLUSH
                        atomic_inc(&dcpage_flushes_xcall);
#endif
                        pg_addr += PAGE_SIZE;
                }
        }
        __local_flush_dcache_folio(folio);

        preempt_enable();
}

#ifdef CONFIG_KGDB
void kgdb_roundup_cpus(void)
{
        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.
 *
 * 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 limit cross calls.
 */

/* 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);

        get_cpu();

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

        __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;

        get_cpu();

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

        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);

        get_cpu();

        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();
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
}

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).max_cache_id ==
                            cpu_data(j).max_cache_id)
                                cpumask_set_cpu(j, &cpu_core_sib_cache_map[i]);

                        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)
{
}

static void send_cpu_ipi(int cpu)
{
        xcall_deliver((u64) &xcall_receive_signal,
                        0, 0, cpumask_of(cpu));
}

void scheduler_poke(void)
{
        if (!cpu_poke)
                return;

        if (!__this_cpu_read(poke))
                return;

        __this_cpu_write(poke, false);
        set_softint(1 << PIL_SMP_RECEIVE_SIGNAL);
}

static unsigned long send_cpu_poke(int cpu)
{
        unsigned long hv_err;

        per_cpu(poke, cpu) = true;
        hv_err = sun4v_cpu_poke(cpu);
        if (hv_err != HV_EOK) {
                per_cpu(poke, cpu) = false;
                pr_err_ratelimited("%s: sun4v_cpu_poke() fails err=%lu\n",
                                    __func__, hv_err);
        }

        return hv_err;
}

void arch_smp_send_reschedule(int cpu)
{
        if (cpu == smp_processor_id()) {
                WARN_ON_ONCE(preemptible());
                set_softint(1 << PIL_SMP_RECEIVE_SIGNAL);
                return;
        }

        /* Use cpu poke to resume idle cpu if supported. */
        if (cpu_poke && idle_cpu(cpu)) {
                unsigned long ret;

                ret = send_cpu_poke(cpu);
                if (ret == HV_EOK)
                        return;
        }

        /* Use IPI in following cases:
         * - cpu poke not supported
         * - cpu not idle
         * - send_cpu_poke() returns with error
         */
        send_cpu_ipi(cpu);
}

void smp_init_cpu_poke(void)
{
        unsigned long major;
        unsigned long minor;
        int ret;

        if (tlb_type != hypervisor)
                return;

        ret = sun4v_hvapi_get(HV_GRP_CORE, &major, &minor);
        if (ret) {
                pr_debug("HV_GRP_CORE is not registered\n");
                return;
        }

        if (major == 1 && minor >= 6) {
                /* CPU POKE is registered. */
                cpu_poke = true;
                return;
        }

        pr_debug("CPU_POKE not supported\n");
}

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)
{
        set_cpu_online(smp_processor_id(), false);
        prom_stopself();
}

void smp_send_stop(void)
{
        int cpu;

        if (tlb_type == hypervisor) {
                int this_cpu = smp_processor_id();
#ifdef CONFIG_SERIAL_SUNHV
                sunhv_migrate_hvcons_irq(this_cpu);
#endif
                for_each_online_cpu(cpu) {
                        if (cpu == this_cpu)
                                continue;

                        set_cpu_online(cpu, false);
#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);
}

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 int __init pcpu_cpu_to_node(int cpu)
{
        return cpu_to_node(cpu);
}

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_cpu_to_node);
                if (rc)
                        pr_warn("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_cpu_to_node);
        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);
}