/*
 *  S/390 helpers
 *
 *  Copyright (c) 2009 Ulrich Hecht
 *  Copyright (c) 2011 Alexander Graf
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

#include "cpu.h"
#include "exec/gdbstub.h"
#include "qemu/timer.h"
#include "exec/cpu_ldst.h"
#ifndef CONFIG_USER_ONLY
#include "sysemu/sysemu.h"
#endif

//#define DEBUG_S390
//#define DEBUG_S390_STDOUT

#ifdef DEBUG_S390
#ifdef DEBUG_S390_STDOUT
#define DPRINTF(fmt, ...) \
    do { fprintf(stderr, fmt, ## __VA_ARGS__); \
         qemu_log(fmt, ##__VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) \
    do { qemu_log(fmt, ## __VA_ARGS__); } while (0)
#endif
#else
#define DPRINTF(fmt, ...) \
    do { } while (0)
#endif


#ifndef CONFIG_USER_ONLY
void s390x_tod_timer(void *opaque)
{
    S390CPU *cpu = opaque;
    CPUS390XState *env = &cpu->env;

    env->pending_int |= INTERRUPT_TOD;
    cpu_interrupt(CPU(cpu), CPU_INTERRUPT_HARD);
}

void s390x_cpu_timer(void *opaque)
{
    S390CPU *cpu = opaque;
    CPUS390XState *env = &cpu->env;

    env->pending_int |= INTERRUPT_CPUTIMER;
    cpu_interrupt(CPU(cpu), CPU_INTERRUPT_HARD);
}
#endif

S390CPU *cpu_s390x_init(const char *cpu_model)
{
    S390CPU *cpu;

    cpu = S390_CPU(object_new(TYPE_S390_CPU));

    object_property_set_bool(OBJECT(cpu), true, "realized", NULL);

    return cpu;
}

#if defined(CONFIG_USER_ONLY)

void s390_cpu_do_interrupt(CPUState *cs)
{
    cs->exception_index = -1;
}

int s390_cpu_handle_mmu_fault(CPUState *cs, vaddr address,
                              int rw, int mmu_idx)
{
    S390CPU *cpu = S390_CPU(cs);

    cs->exception_index = EXCP_PGM;
    cpu->env.int_pgm_code = PGM_ADDRESSING;
    /* On real machines this value is dropped into LowMem.  Since this
       is userland, simply put this someplace that cpu_loop can find it.  */
    cpu->env.__excp_addr = address;
    return 1;
}

#else /* !CONFIG_USER_ONLY */

/* Ensure to exit the TB after this call! */
void trigger_pgm_exception(CPUS390XState *env, uint32_t code, uint32_t ilen)
{
    CPUState *cs = CPU(s390_env_get_cpu(env));

    cs->exception_index = EXCP_PGM;
    env->int_pgm_code = code;
    env->int_pgm_ilen = ilen;
}

int s390_cpu_handle_mmu_fault(CPUState *cs, vaddr orig_vaddr,
                              int rw, int mmu_idx)
{
    S390CPU *cpu = S390_CPU(cs);
    CPUS390XState *env = &cpu->env;
    uint64_t asc = env->psw.mask & PSW_MASK_ASC;
    target_ulong vaddr, raddr;
    int prot;

    DPRINTF("%s: address 0x%" VADDR_PRIx " rw %d mmu_idx %d\n",
            __func__, orig_vaddr, rw, mmu_idx);

    orig_vaddr &= TARGET_PAGE_MASK;
    vaddr = orig_vaddr;

    /* 31-Bit mode */
    if (!(env->psw.mask & PSW_MASK_64)) {
        vaddr &= 0x7fffffff;
    }

    if (mmu_translate(env, vaddr, rw, asc, &raddr, &prot, true)) {
        /* Translation ended in exception */
        return 1;
    }

    /* check out of RAM access */
    if (raddr > (ram_size + virtio_size)) {
        DPRINTF("%s: raddr %" PRIx64 " > ram_size %" PRIx64 "\n", __func__,
                (uint64_t)raddr, (uint64_t)ram_size);
        trigger_pgm_exception(env, PGM_ADDRESSING, ILEN_LATER);
        return 1;
    }

    qemu_log_mask(CPU_LOG_MMU, "%s: set tlb %" PRIx64 " -> %" PRIx64 " (%x)\n",
            __func__, (uint64_t)vaddr, (uint64_t)raddr, prot);

    tlb_set_page(cs, orig_vaddr, raddr, prot,
                 mmu_idx, TARGET_PAGE_SIZE);

    return 0;
}

hwaddr s390_cpu_get_phys_page_debug(CPUState *cs, vaddr vaddr)
{
    S390CPU *cpu = S390_CPU(cs);
    CPUS390XState *env = &cpu->env;
    target_ulong raddr;
    int prot;
    uint64_t asc = env->psw.mask & PSW_MASK_ASC;

    /* 31-Bit mode */
    if (!(env->psw.mask & PSW_MASK_64)) {
        vaddr &= 0x7fffffff;
    }

    mmu_translate(env, vaddr, MMU_INST_FETCH, asc, &raddr, &prot, false);

    return raddr;
}

hwaddr s390_cpu_get_phys_addr_debug(CPUState *cs, vaddr vaddr)
{
    hwaddr phys_addr;
    target_ulong page;

    page = vaddr & TARGET_PAGE_MASK;
    phys_addr = cpu_get_phys_page_debug(cs, page);
    phys_addr += (vaddr & ~TARGET_PAGE_MASK);

    return phys_addr;
}

void load_psw(CPUS390XState *env, uint64_t mask, uint64_t addr)
{
    env->psw.addr = addr;
    env->psw.mask = mask;
    if (tcg_enabled()) {
        env->cc_op = (mask >> 44) & 3;
    }

    if (mask & PSW_MASK_WAIT) {
        S390CPU *cpu = s390_env_get_cpu(env);
        if (s390_cpu_halt(cpu) == 0) {
#ifndef CONFIG_USER_ONLY
            qemu_system_shutdown_request();
#endif
        }
    }
}

static uint64_t get_psw_mask(CPUS390XState *env)
{
    uint64_t r = env->psw.mask;

    if (tcg_enabled()) {
        env->cc_op = calc_cc(env, env->cc_op, env->cc_src, env->cc_dst,
                             env->cc_vr);

        r &= ~PSW_MASK_CC;
        assert(!(env->cc_op & ~3));
        r |= (uint64_t)env->cc_op << 44;
    }

    return r;
}

static LowCore *cpu_map_lowcore(CPUS390XState *env)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    LowCore *lowcore;
    hwaddr len = sizeof(LowCore);

    lowcore = cpu_physical_memory_map(env->psa, &len, 1);

    if (len < sizeof(LowCore)) {
        cpu_abort(CPU(cpu), "Could not map lowcore\n");
    }

    return lowcore;
}

static void cpu_unmap_lowcore(LowCore *lowcore)
{
    cpu_physical_memory_unmap(lowcore, sizeof(LowCore), 1, sizeof(LowCore));
}

void do_restart_interrupt(CPUS390XState *env)
{
    uint64_t mask, addr;
    LowCore *lowcore;

    lowcore = cpu_map_lowcore(env);

    lowcore->restart_old_psw.mask = cpu_to_be64(get_psw_mask(env));
    lowcore->restart_old_psw.addr = cpu_to_be64(env->psw.addr);
    mask = be64_to_cpu(lowcore->restart_new_psw.mask);
    addr = be64_to_cpu(lowcore->restart_new_psw.addr);

    cpu_unmap_lowcore(lowcore);

    load_psw(env, mask, addr);
}

static void do_svc_interrupt(CPUS390XState *env)
{
    uint64_t mask, addr;
    LowCore *lowcore;

    lowcore = cpu_map_lowcore(env);

    lowcore->svc_code = cpu_to_be16(env->int_svc_code);
    lowcore->svc_ilen = cpu_to_be16(env->int_svc_ilen);
    lowcore->svc_old_psw.mask = cpu_to_be64(get_psw_mask(env));
    lowcore->svc_old_psw.addr = cpu_to_be64(env->psw.addr + env->int_svc_ilen);
    mask = be64_to_cpu(lowcore->svc_new_psw.mask);
    addr = be64_to_cpu(lowcore->svc_new_psw.addr);

    cpu_unmap_lowcore(lowcore);

    load_psw(env, mask, addr);
}

static void do_program_interrupt(CPUS390XState *env)
{
    uint64_t mask, addr;
    LowCore *lowcore;
    int ilen = env->int_pgm_ilen;

    switch (ilen) {
    case ILEN_LATER:
        ilen = get_ilen(cpu_ldub_code(env, env->psw.addr));
        break;
    case ILEN_LATER_INC:
        ilen = get_ilen(cpu_ldub_code(env, env->psw.addr));
        env->psw.addr += ilen;
        break;
    default:
        assert(ilen == 2 || ilen == 4 || ilen == 6);
    }

    qemu_log_mask(CPU_LOG_INT, "%s: code=0x%x ilen=%d\n",
                  __func__, env->int_pgm_code, ilen);

    lowcore = cpu_map_lowcore(env);

    lowcore->pgm_ilen = cpu_to_be16(ilen);
    lowcore->pgm_code = cpu_to_be16(env->int_pgm_code);
    lowcore->program_old_psw.mask = cpu_to_be64(get_psw_mask(env));
    lowcore->program_old_psw.addr = cpu_to_be64(env->psw.addr);
    mask = be64_to_cpu(lowcore->program_new_psw.mask);
    addr = be64_to_cpu(lowcore->program_new_psw.addr);

    cpu_unmap_lowcore(lowcore);

    DPRINTF("%s: %x %x %" PRIx64 " %" PRIx64 "\n", __func__,
            env->int_pgm_code, ilen, env->psw.mask,
            env->psw.addr);

    load_psw(env, mask, addr);
}

#define VIRTIO_SUBCODE_64 0x0D00

static void do_ext_interrupt(CPUS390XState *env)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    uint64_t mask, addr;
    LowCore *lowcore;
    ExtQueue *q;

    if (!(env->psw.mask & PSW_MASK_EXT)) {
        cpu_abort(CPU(cpu), "Ext int w/o ext mask\n");
    }

    if (env->ext_index < 0 || env->ext_index >= MAX_EXT_QUEUE) {
        cpu_abort(CPU(cpu), "Ext queue overrun: %d\n", env->ext_index);
    }

    q = &env->ext_queue[env->ext_index];
    lowcore = cpu_map_lowcore(env);

    lowcore->ext_int_code = cpu_to_be16(q->code);
    lowcore->ext_params = cpu_to_be32(q->param);
    lowcore->ext_params2 = cpu_to_be64(q->param64);
    lowcore->external_old_psw.mask = cpu_to_be64(get_psw_mask(env));
    lowcore->external_old_psw.addr = cpu_to_be64(env->psw.addr);
    lowcore->cpu_addr = cpu_to_be16(env->cpu_num | VIRTIO_SUBCODE_64);
    mask = be64_to_cpu(lowcore->external_new_psw.mask);
    addr = be64_to_cpu(lowcore->external_new_psw.addr);

    cpu_unmap_lowcore(lowcore);

    env->ext_index--;
    if (env->ext_index == -1) {
        env->pending_int &= ~INTERRUPT_EXT;
    }

    DPRINTF("%s: %" PRIx64 " %" PRIx64 "\n", __func__,
            env->psw.mask, env->psw.addr);

    load_psw(env, mask, addr);
}

static void do_io_interrupt(CPUS390XState *env)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    LowCore *lowcore;
    IOIntQueue *q;
    uint8_t isc;
    int disable = 1;
    int found = 0;

    if (!(env->psw.mask & PSW_MASK_IO)) {
        cpu_abort(CPU(cpu), "I/O int w/o I/O mask\n");
    }

    for (isc = 0; isc < ARRAY_SIZE(env->io_index); isc++) {
        uint64_t isc_bits;

        if (env->io_index[isc] < 0) {
            continue;
        }
        if (env->io_index[isc] >= MAX_IO_QUEUE) {
            cpu_abort(CPU(cpu), "I/O queue overrun for isc %d: %d\n",
                      isc, env->io_index[isc]);
        }

        q = &env->io_queue[env->io_index[isc]][isc];
        isc_bits = ISC_TO_ISC_BITS(IO_INT_WORD_ISC(q->word));
        if (!(env->cregs[6] & isc_bits)) {
            disable = 0;
            continue;
        }
        if (!found) {
            uint64_t mask, addr;

            found = 1;
            lowcore = cpu_map_lowcore(env);

            lowcore->subchannel_id = cpu_to_be16(q->id);
            lowcore->subchannel_nr = cpu_to_be16(q->nr);
            lowcore->io_int_parm = cpu_to_be32(q->parm);
            lowcore->io_int_word = cpu_to_be32(q->word);
            lowcore->io_old_psw.mask = cpu_to_be64(get_psw_mask(env));
            lowcore->io_old_psw.addr = cpu_to_be64(env->psw.addr);
            mask = be64_to_cpu(lowcore->io_new_psw.mask);
            addr = be64_to_cpu(lowcore->io_new_psw.addr);

            cpu_unmap_lowcore(lowcore);

            env->io_index[isc]--;

            DPRINTF("%s: %" PRIx64 " %" PRIx64 "\n", __func__,
                    env->psw.mask, env->psw.addr);
            load_psw(env, mask, addr);
        }
        if (env->io_index[isc] >= 0) {
            disable = 0;
        }
        continue;
    }

    if (disable) {
        env->pending_int &= ~INTERRUPT_IO;
    }

}

static void do_mchk_interrupt(CPUS390XState *env)
{
    S390CPU *cpu = s390_env_get_cpu(env);
    uint64_t mask, addr;
    LowCore *lowcore;
    MchkQueue *q;
    int i;

    if (!(env->psw.mask & PSW_MASK_MCHECK)) {
        cpu_abort(CPU(cpu), "Machine check w/o mchk mask\n");
    }

    if (env->mchk_index < 0 || env->mchk_index >= MAX_MCHK_QUEUE) {
        cpu_abort(CPU(cpu), "Mchk queue overrun: %d\n", env->mchk_index);
    }

    q = &env->mchk_queue[env->mchk_index];

    if (q->type != 1) {
        /* Don't know how to handle this... */
        cpu_abort(CPU(cpu), "Unknown machine check type %d\n", q->type);
    }
    if (!(env->cregs[14] & (1 << 28))) {
        /* CRW machine checks disabled */
        return;
    }

    lowcore = cpu_map_lowcore(env);

    for (i = 0; i < 16; i++) {
        lowcore->floating_pt_save_area[i] = cpu_to_be64(env->fregs[i].ll);
        lowcore->gpregs_save_area[i] = cpu_to_be64(env->regs[i]);
        lowcore->access_regs_save_area[i] = cpu_to_be32(env->aregs[i]);
        lowcore->cregs_save_area[i] = cpu_to_be64(env->cregs[i]);
    }
    lowcore->prefixreg_save_area = cpu_to_be32(env->psa);
    lowcore->fpt_creg_save_area = cpu_to_be32(env->fpc);
    lowcore->tod_progreg_save_area = cpu_to_be32(env->todpr);
    lowcore->cpu_timer_save_area[0] = cpu_to_be32(env->cputm >> 32);
    lowcore->cpu_timer_save_area[1] = cpu_to_be32((uint32_t)env->cputm);
    lowcore->clock_comp_save_area[0] = cpu_to_be32(env->ckc >> 32);
    lowcore->clock_comp_save_area[1] = cpu_to_be32((uint32_t)env->ckc);

    lowcore->mcck_interruption_code[0] = cpu_to_be32(0x00400f1d);
    lowcore->mcck_interruption_code[1] = cpu_to_be32(0x40330000);
    lowcore->mcck_old_psw.mask = cpu_to_be64(get_psw_mask(env));
    lowcore->mcck_old_psw.addr = cpu_to_be64(env->psw.addr);
    mask = be64_to_cpu(lowcore->mcck_new_psw.mask);
    addr = be64_to_cpu(lowcore->mcck_new_psw.addr);

    cpu_unmap_lowcore(lowcore);

    env->mchk_index--;
    if (env->mchk_index == -1) {
        env->pending_int &= ~INTERRUPT_MCHK;
    }

    DPRINTF("%s: %" PRIx64 " %" PRIx64 "\n", __func__,
            env->psw.mask, env->psw.addr);

    load_psw(env, mask, addr);
}

void s390_cpu_do_interrupt(CPUState *cs)
{
    S390CPU *cpu = S390_CPU(cs);
    CPUS390XState *env = &cpu->env;

    qemu_log_mask(CPU_LOG_INT, "%s: %d at pc=%" PRIx64 "\n",
                  __func__, cs->exception_index, env->psw.addr);

    s390_cpu_set_state(CPU_STATE_OPERATING, cpu);
    /* handle machine checks */
    if ((env->psw.mask & PSW_MASK_MCHECK) &&
        (cs->exception_index == -1)) {
        if (env->pending_int & INTERRUPT_MCHK) {
            cs->exception_index = EXCP_MCHK;
        }
    }
    /* handle external interrupts */
    if ((env->psw.mask & PSW_MASK_EXT) &&
        cs->exception_index == -1) {
        if (env->pending_int & INTERRUPT_EXT) {
            /* code is already in env */
            cs->exception_index = EXCP_EXT;
        } else if (env->pending_int & INTERRUPT_TOD) {
            cpu_inject_ext(cpu, 0x1004, 0, 0);
            cs->exception_index = EXCP_EXT;
            env->pending_int &= ~INTERRUPT_EXT;
            env->pending_int &= ~INTERRUPT_TOD;
        } else if (env->pending_int & INTERRUPT_CPUTIMER) {
            cpu_inject_ext(cpu, 0x1005, 0, 0);
            cs->exception_index = EXCP_EXT;
            env->pending_int &= ~INTERRUPT_EXT;
            env->pending_int &= ~INTERRUPT_TOD;
        }
    }
    /* handle I/O interrupts */
    if ((env->psw.mask & PSW_MASK_IO) &&
        (cs->exception_index == -1)) {
        if (env->pending_int & INTERRUPT_IO) {
            cs->exception_index = EXCP_IO;
        }
    }

    switch (cs->exception_index) {
    case EXCP_PGM:
        do_program_interrupt(env);
        break;
    case EXCP_SVC:
        do_svc_interrupt(env);
        break;
    case EXCP_EXT:
        do_ext_interrupt(env);
        break;
    case EXCP_IO:
        do_io_interrupt(env);
        break;
    case EXCP_MCHK:
        do_mchk_interrupt(env);
        break;
    }
    cs->exception_index = -1;

    if (!env->pending_int) {
        cs->interrupt_request &= ~CPU_INTERRUPT_HARD;
    }
}

bool s390_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
{
    if (interrupt_request & CPU_INTERRUPT_HARD) {
        S390CPU *cpu = S390_CPU(cs);
        CPUS390XState *env = &cpu->env;

        if (env->psw.mask & PSW_MASK_EXT) {
            s390_cpu_do_interrupt(cs);
            return true;
        }
    }
    return false;
}
#endif /* CONFIG_USER_ONLY */