/*
 * arch/ia64/kernel/crash.c
 *
 * Architecture specific (ia64) functions for kexec based crash dumps.
 *
 * Created by: Khalid Aziz <khalid.aziz@hp.com>
 * Copyright (C) 2005 Hewlett-Packard Development Company, L.P.
 * Copyright (C) 2005 Intel Corp        Zou Nan hai <nanhai.zou@intel.com>
 *
 */
#include <linux/smp.h>
#include <linux/delay.h>
#include <linux/crash_dump.h>
#include <linux/bootmem.h>
#include <linux/kexec.h>
#include <linux/elfcore.h>
#include <linux/sysctl.h>
#include <linux/init.h>
#include <linux/kdebug.h>

#include <asm/mca.h>

int kdump_status[NR_CPUS];
static atomic_t kdump_cpu_frozen;
atomic_t kdump_in_progress;
static int kdump_freeze_monarch;
static int kdump_on_init = 1;
static int kdump_on_fatal_mca = 1;

static inline Elf64_Word
*append_elf_note(Elf64_Word *buf, char *name, unsigned type, void *data,
                size_t data_len)
{
        struct elf_note *note = (struct elf_note *)buf;
        note->n_namesz = strlen(name) + 1;
        note->n_descsz = data_len;
        note->n_type   = type;
        buf += (sizeof(*note) + 3)/4;
        memcpy(buf, name, note->n_namesz);
        buf += (note->n_namesz + 3)/4;
        memcpy(buf, data, data_len);
        buf += (data_len + 3)/4;
        return buf;
}

static void
final_note(void *buf)
{
        memset(buf, 0, sizeof(struct elf_note));
}

extern void ia64_dump_cpu_regs(void *);

static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus);

void
crash_save_this_cpu(void)
{
        void *buf;
        unsigned long cfm, sof, sol;

        int cpu = smp_processor_id();
        struct elf_prstatus *prstatus = &per_cpu(elf_prstatus, cpu);

        elf_greg_t *dst = (elf_greg_t *)&(prstatus->pr_reg);
        memset(prstatus, 0, sizeof(*prstatus));
        prstatus->pr_pid = current->pid;

        ia64_dump_cpu_regs(dst);
        cfm = dst[43];
        sol = (cfm >> 7) & 0x7f;
        sof = cfm & 0x7f;
        dst[46] = (unsigned long)ia64_rse_skip_regs((unsigned long *)dst[46],
                        sof - sol);

        buf = (u64 *) per_cpu_ptr(crash_notes, cpu);
        if (!buf)
                return;
        buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS, prstatus,
                        sizeof(*prstatus));
        final_note(buf);
}

#ifdef CONFIG_SMP
static int
kdump_wait_cpu_freeze(void)
{
        int cpu_num = num_online_cpus() - 1;
        int timeout = 1000;
        while(timeout-- > 0) {
                if (atomic_read(&kdump_cpu_frozen) == cpu_num)
                        return 0;
                udelay(1000);
        }
        return 1;
}
#endif

void
machine_crash_shutdown(struct pt_regs *pt)
{
        /* This function is only called after the system
         * has paniced or is otherwise in a critical state.
         * The minimum amount of code to allow a kexec'd kernel
         * to run successfully needs to happen here.
         *
         * In practice this means shooting down the other cpus in
         * an SMP system.
         */
        kexec_disable_iosapic();
#ifdef CONFIG_SMP
        /*
         * If kdump_on_init is set and an INIT is asserted here, kdump will
         * be started again via INIT monarch.
         */
        local_irq_disable();
        ia64_set_psr_mc();      /* mask MCA/INIT */
        if (atomic_inc_return(&kdump_in_progress) != 1)
                unw_init_running(kdump_cpu_freeze, NULL);

        /*
         * Now this cpu is ready for kdump.
         * Stop all others by IPI or INIT.  They could receive INIT from
         * outside and might be INIT monarch, but only thing they have to
         * do is falling into kdump_cpu_freeze().
         *
         * If an INIT is asserted here:
         * - All receivers might be slaves, since some of cpus could already
         *   be frozen and INIT might be masked on monarch.  In this case,
         *   all slaves will be frozen soon since kdump_in_progress will let
         *   them into DIE_INIT_SLAVE_LEAVE.
         * - One might be a monarch, but INIT rendezvous will fail since
         *   at least this cpu already have INIT masked so it never join
         *   to the rendezvous.  In this case, all slaves and monarch will
         *   be frozen soon with no wait since the INIT rendezvous is skipped
         *   by kdump_in_progress.
         */
        kdump_smp_send_stop();
        /* not all cpu response to IPI, send INIT to freeze them */
        if (kdump_wait_cpu_freeze()) {
                kdump_smp_send_init();
                /* wait again, don't go ahead if possible */
                kdump_wait_cpu_freeze();
        }
#endif
}

static void
machine_kdump_on_init(void)
{
        crash_save_vmcoreinfo();
        local_irq_disable();
        kexec_disable_iosapic();
        machine_kexec(ia64_kimage);
}

void
kdump_cpu_freeze(struct unw_frame_info *info, void *arg)
{
        int cpuid;

        local_irq_disable();
        cpuid = smp_processor_id();
        crash_save_this_cpu();
        current->thread.ksp = (__u64)info->sw - 16;

        ia64_set_psr_mc();      /* mask MCA/INIT and stop reentrance */

        atomic_inc(&kdump_cpu_frozen);
        kdump_status[cpuid] = 1;
        mb();
        for (;;)
                cpu_relax();
}

static int
kdump_init_notifier(struct notifier_block *self, unsigned long val, void *data)
{
        struct ia64_mca_notify_die *nd;
        struct die_args *args = data;

        if (atomic_read(&kdump_in_progress)) {
                switch (val) {
                case DIE_INIT_MONARCH_LEAVE:
                        if (!kdump_freeze_monarch)
                                break;
                        /* fall through */
                case DIE_INIT_SLAVE_LEAVE:
                case DIE_INIT_MONARCH_ENTER:
                case DIE_MCA_RENDZVOUS_LEAVE:
                        unw_init_running(kdump_cpu_freeze, NULL);
                        break;
                }
        }

        if (!kdump_on_init && !kdump_on_fatal_mca)
                return NOTIFY_DONE;

        if (!ia64_kimage) {
                if (val == DIE_INIT_MONARCH_LEAVE)
                        ia64_mca_printk(KERN_NOTICE
                                        "%s: kdump not configured\n",
                                        __func__);
                return NOTIFY_DONE;
        }

        if (val != DIE_INIT_MONARCH_LEAVE &&
            val != DIE_INIT_MONARCH_PROCESS &&
            val != DIE_MCA_MONARCH_LEAVE)
                return NOTIFY_DONE;

        nd = (struct ia64_mca_notify_die *)args->err;

        switch (val) {
        case DIE_INIT_MONARCH_PROCESS:
                /* Reason code 1 means machine check rendezvous*/
                if (kdump_on_init && (nd->sos->rv_rc != 1)) {
                        if (atomic_inc_return(&kdump_in_progress) != 1)
                                kdump_freeze_monarch = 1;
                }
                break;
        case DIE_INIT_MONARCH_LEAVE:
                /* Reason code 1 means machine check rendezvous*/
                if (kdump_on_init && (nd->sos->rv_rc != 1))
                        machine_kdump_on_init();
                break;
        case DIE_MCA_MONARCH_LEAVE:
                /* *(nd->data) indicate if MCA is recoverable */
                if (kdump_on_fatal_mca && !(*(nd->data))) {
                        if (atomic_inc_return(&kdump_in_progress) == 1)
                                machine_kdump_on_init();
                        /* We got fatal MCA while kdump!? No way!! */
                }
                break;
        }
        return NOTIFY_DONE;
}

#ifdef CONFIG_SYSCTL
static struct ctl_table kdump_ctl_table[] = {
        {
                .procname = "kdump_on_init",
                .data = &kdump_on_init,
                .maxlen = sizeof(int),
                .mode = 0644,
                .proc_handler = proc_dointvec,
        },
        {
                .procname = "kdump_on_fatal_mca",
                .data = &kdump_on_fatal_mca,
                .maxlen = sizeof(int),
                .mode = 0644,
                .proc_handler = proc_dointvec,
        },
        { }
};

static struct ctl_table sys_table[] = {
        {
          .procname = "kernel",
          .mode = 0555,
          .child = kdump_ctl_table,
        },
        { }
};
#endif

static int
machine_crash_setup(void)
{
        /* be notified before default_monarch_init_process */
        static struct notifier_block kdump_init_notifier_nb = {
                .notifier_call = kdump_init_notifier,
                .priority = 1,
        };
        int ret;
        if((ret = register_die_notifier(&kdump_init_notifier_nb)) != 0)
                return ret;
#ifdef CONFIG_SYSCTL
        register_sysctl_table(sys_table);
#endif
        return 0;
}

__initcall(machine_crash_setup);