/*
 * QEMU RISC-V CPU
 *
 * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
 * Copyright (c) 2017-2018 SiFive, Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2 or later, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "qemu/osdep.h"
#include "qemu/log.h"
#include "cpu.h"
#include "exec/exec-all.h"
#include "qapi/error.h"

#include "uc_priv.h"

/* RISC-V CPU definitions */

const char * const riscv_int_regnames[] = {
  "zero", "ra  ", "sp  ", "gp  ", "tp  ", "t0  ", "t1  ", "t2  ",
  "s0  ", "s1  ", "a0  ", "a1  ", "a2  ", "a3  ", "a4  ", "a5  ",
  "a6  ", "a7  ", "s2  ", "s3  ", "s4  ", "s5  ", "s6  ", "s7  ",
  "s8  ", "s9  ", "s10 ", "s11 ", "t3  ", "t4  ", "t5  ", "t6  "
};

const char * const riscv_fpr_regnames[] = {
  "ft0 ", "ft1 ", "ft2 ", "ft3 ", "ft4 ", "ft5 ", "ft6 ",  "ft7 ",
  "fs0 ", "fs1 ", "fa0 ", "fa1 ", "fa2 ", "fa3 ", "fa4 ",  "fa5 ",
  "fa6 ", "fa7 ", "fs2 ", "fs3 ", "fs4 ", "fs5 ", "fs6 ",  "fs7 ",
  "fs8 ", "fs9 ", "fs10", "fs11", "ft8 ", "ft9 ", "ft10",  "ft11"
};

const char * const riscv_excp_names[] = {
    "misaligned_fetch",
    "fault_fetch",
    "illegal_instruction",
    "breakpoint",
    "misaligned_load",
    "fault_load",
    "misaligned_store",
    "fault_store",
    "user_ecall",
    "supervisor_ecall",
    "hypervisor_ecall",
    "machine_ecall",
    "exec_page_fault",
    "load_page_fault",
    "reserved",
    "store_page_fault"
};

const char * const riscv_intr_names[] = {
    "u_software",
    "s_software",
    "h_software",
    "m_software",
    "u_timer",
    "s_timer",
    "h_timer",
    "m_timer",
    "u_external",
    "s_external",
    "h_external",
    "m_external",
    "reserved",
    "reserved",
    "reserved",
    "reserved"
};

static void set_misa(CPURISCVState *env, target_ulong misa)
{
    env->misa_mask = env->misa = misa;
}

static void set_versions(CPURISCVState *env, int user_ver, int priv_ver)
{
    env->user_ver = user_ver;
    env->priv_ver = priv_ver;
}

static void set_feature(CPURISCVState *env, int feature)
{
    env->features |= (1ULL << feature);
}

static void set_resetvec(CPURISCVState *env, int resetvec)
{
#ifndef CONFIG_USER_ONLY
    env->resetvec = resetvec;
#endif
}

static void riscv_any_cpu_init(struct uc_struct *uc, Object *obj, void *opaque)
{
    CPURISCVState *env = &RISCV_CPU(uc, obj)->env;
    set_misa(env, RVXLEN | RVI | RVM | RVA | RVF | RVD | RVC | RVU);
    set_versions(env, USER_VERSION_2_02_0, PRIV_VERSION_1_10_0);
    set_resetvec(env, DEFAULT_RSTVEC);
}

#if defined(TARGET_RISCV32)

static void rv32gcsu_priv1_09_1_cpu_init(struct uc_struct *uc, Object *obj, void *opaque)
{
    CPURISCVState *env = &RISCV_CPU(uc, obj)->env;
    set_misa(env, RV32 | RVI | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
    set_versions(env, USER_VERSION_2_02_0, PRIV_VERSION_1_09_1);
    set_resetvec(env, DEFAULT_RSTVEC);
    set_feature(env, RISCV_FEATURE_MMU);
    set_feature(env, RISCV_FEATURE_PMP);
}

static void rv32gcsu_priv1_10_0_cpu_init(struct uc_struct *uc, Object *obj, void *opaque)
{
    CPURISCVState *env = &RISCV_CPU(uc, obj)->env;
    set_misa(env, RV32 | RVI | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
    set_versions(env, USER_VERSION_2_02_0, PRIV_VERSION_1_10_0);
    set_resetvec(env, DEFAULT_RSTVEC);
    set_feature(env, RISCV_FEATURE_MMU);
    set_feature(env, RISCV_FEATURE_PMP);
}

static void rv32imacu_nommu_cpu_init(struct uc_struct *uc, Object *obj, void *opaque)
{
    CPURISCVState *env = &RISCV_CPU(uc, obj)->env;
    set_misa(env, RV32 | RVI | RVM | RVA | RVC | RVU);
    set_versions(env, USER_VERSION_2_02_0, PRIV_VERSION_1_10_0);
    set_resetvec(env, DEFAULT_RSTVEC);
    set_feature(env, RISCV_FEATURE_PMP);
}

#elif defined(TARGET_RISCV64)

static void rv64gcsu_priv1_09_1_cpu_init(struct uc_struct *uc, Object *obj, void *opaque)
{
    CPURISCVState *env = &RISCV_CPU(uc, obj)->env;
    set_misa(env, RV64 | RVI | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
    set_versions(env, USER_VERSION_2_02_0, PRIV_VERSION_1_09_1);
    set_resetvec(env, DEFAULT_RSTVEC);
    set_feature(env, RISCV_FEATURE_MMU);
    set_feature(env, RISCV_FEATURE_PMP);
}

static void rv64gcsu_priv1_10_0_cpu_init(struct uc_struct *uc, Object *obj, void *opaque)
{
    CPURISCVState *env = &RISCV_CPU(uc, obj)->env;
    set_misa(env, RV64 | RVI | RVM | RVA | RVF | RVD | RVC | RVS | RVU);
    set_versions(env, USER_VERSION_2_02_0, PRIV_VERSION_1_10_0);
    set_resetvec(env, DEFAULT_RSTVEC);
    set_feature(env, RISCV_FEATURE_MMU);
    set_feature(env, RISCV_FEATURE_PMP);
}

static void rv64imacu_nommu_cpu_init(struct uc_struct *uc, Object *obj, void *opaque)
{
    CPURISCVState *env = &RISCV_CPU(uc, obj)->env;
    set_misa(env, RV64 | RVI | RVM | RVA | RVC | RVU);
    set_versions(env, USER_VERSION_2_02_0, PRIV_VERSION_1_10_0);
    set_resetvec(env, DEFAULT_RSTVEC);
    set_feature(env, RISCV_FEATURE_PMP);
}

#endif

static ObjectClass *riscv_cpu_class_by_name(struct uc_struct *uc, const char *cpu_model)
{
    ObjectClass *oc;
    char *typename;
    char **cpuname;

    cpuname = g_strsplit(cpu_model, ",", 1);
    typename = g_strdup_printf(RISCV_CPU_TYPE_NAME("%s"), cpuname[0]);
    oc = object_class_by_name(uc, typename);
    g_strfreev(cpuname);
    g_free(typename);
    if (!oc || !object_class_dynamic_cast(uc, oc, TYPE_RISCV_CPU) ||
        object_class_is_abstract(oc)) {
        return NULL;
    }
    return oc;
}

// Unicorn: if'd out
#if 0
static void riscv_cpu_dump_state(CPUState *cs, FILE *f,
    fprintf_function cpu_fprintf, int flags)
{
    RISCVCPU *cpu = RISCV_CPU(cs);
    CPURISCVState *env = &cpu->env;
    int i;

    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "pc      ", env->pc);
#ifndef CONFIG_USER_ONLY
    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mhartid ", env->mhartid);
    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mstatus ", env->mstatus);
    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mip     ",
        (target_ulong)atomic_read(&env->mip));
    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mie     ", env->mie);
    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mideleg ", env->mideleg);
    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "medeleg ", env->medeleg);
    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mtvec   ", env->mtvec);
    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mepc    ", env->mepc);
    cpu_fprintf(f, " %s " TARGET_FMT_lx "\n", "mcause  ", env->mcause);
#endif

    for (i = 0; i < 32; i++) {
        cpu_fprintf(f, " %s " TARGET_FMT_lx,
            riscv_int_regnames[i], env->gpr[i]);
        if ((i & 3) == 3) {
            cpu_fprintf(f, "\n");
        }
    }
    if (flags & CPU_DUMP_FPU) {
        for (i = 0; i < 32; i++) {
            cpu_fprintf(f, " %s %016" PRIx64,
                riscv_fpr_regnames[i], env->fpr[i]);
            if ((i & 3) == 3) {
                cpu_fprintf(f, "\n");
            }
        }
    }
}
#endif

static void riscv_cpu_set_pc(CPUState *cs, vaddr value)
{
    RISCVCPU *cpu = RISCV_CPU(cs->uc, cs);
    CPURISCVState *env = &cpu->env;
    env->pc = value;
}

static void riscv_cpu_synchronize_from_tb(CPUState *cs, TranslationBlock *tb)
{
    RISCVCPU *cpu = RISCV_CPU(cs->uc, cs);
    CPURISCVState *env = &cpu->env;
    env->pc = tb->pc;
}

static bool riscv_cpu_has_work(CPUState *cs)
{
#ifndef CONFIG_USER_ONLY
    RISCVCPU *cpu = RISCV_CPU(cs->uc, cs);
    CPURISCVState *env = &cpu->env;
    /*
     * Definition of the WFI instruction requires it to ignore the privilege
     * mode and delegation registers, but respect individual enables
     */
    return (atomic_read(&env->mip) & env->mie) != 0;
#else
    return true;
#endif
}

void restore_state_to_opc(CPURISCVState *env, TranslationBlock *tb,
                          target_ulong *data)
{
    env->pc = data[0];
}

static void riscv_cpu_reset(CPUState *cs)
{
    RISCVCPU *cpu = RISCV_CPU(cs->uc, cs);
    RISCVCPUClass *mcc = RISCV_CPU_GET_CLASS(cs->uc, cpu);
    CPURISCVState *env = &cpu->env;

    mcc->parent_reset(cs);
#ifndef CONFIG_USER_ONLY
    env->priv = PRV_M;
    env->mstatus &= ~(MSTATUS_MIE | MSTATUS_MPRV);
    env->mcause = 0;
    env->pc = env->resetvec;
#endif
    cs->exception_index = EXCP_NONE;
    set_default_nan_mode(1, &env->fp_status);
}

// Unicorn: if'd out
#if 0
static void riscv_cpu_disas_set_info(CPUState *s, disassemble_info *info)
{
#if defined(TARGET_RISCV32)
    info->print_insn = print_insn_riscv32;
#elif defined(TARGET_RISCV64)
    info->print_insn = print_insn_riscv64;
#endif
}
#endif

static int riscv_cpu_realize(struct uc_struct *uc, DeviceState *dev, Error **errp)
{
    CPUState *cs = CPU(dev);
    RISCVCPUClass *mcc = RISCV_CPU_GET_CLASS(uc, dev);

    cpu_reset(cs);
    qemu_init_vcpu(cs);

    mcc->parent_realize(uc, dev, errp);
    return 0;
}

static void riscv_cpu_init(struct uc_struct *uc, Object *obj, void *opaque)
{
    CPUState *cs = CPU(obj);
    RISCVCPU *cpu = RISCV_CPU(uc, obj);
    CPURISCVState *env = &cpu->env;

    cs->env_ptr = env;
    cpu_exec_init(cs, &error_abort, opaque);
}

static void riscv_cpu_class_init(struct uc_struct *uc, ObjectClass *oc, void *data)
{
    RISCVCPUClass *mcc = RISCV_CPU_CLASS(uc, oc);
    CPUClass *cc = CPU_CLASS(uc, oc);
    DeviceClass *dc = DEVICE_CLASS(uc, oc);

    mcc->parent_realize = dc->realize;
    dc->realize = riscv_cpu_realize;

    mcc->parent_reset = cc->reset;
    cc->reset = riscv_cpu_reset;

    cc->class_by_name = riscv_cpu_class_by_name;
    cc->has_work = riscv_cpu_has_work;
    cc->do_interrupt = riscv_cpu_do_interrupt;
    cc->cpu_exec_interrupt = riscv_cpu_exec_interrupt;
    //cc->dump_state = riscv_cpu_dump_state;
    cc->set_pc = riscv_cpu_set_pc;
    cc->synchronize_from_tb = riscv_cpu_synchronize_from_tb;
    //cc->gdb_read_register = riscv_cpu_gdb_read_register;
    //cc->gdb_write_register = riscv_cpu_gdb_write_register;
    //cc->gdb_num_core_regs = 65;
    //cc->gdb_stop_before_watchpoint = true;
    //cc->disas_set_info = riscv_cpu_disas_set_info;
#ifdef CONFIG_USER_ONLY
    cc->handle_mmu_fault = riscv_cpu_handle_mmu_fault;
#else
    cc->do_unaligned_access = riscv_cpu_do_unaligned_access;
    cc->get_phys_page_debug = riscv_cpu_get_phys_page_debug;
#endif
#ifdef CONFIG_TCG
    cc->tcg_initialize = riscv_translate_init;
#endif
    /* For now, mark unmigratable: */
    //cc->vmsd = &vmstate_riscv_cpu;
}

#define DEFINE_CPU(type_name, initfn)      \
    {                                      \
        .name = type_name,                 \
        .parent = TYPE_RISCV_CPU,          \
        .instance_init = initfn            \
    }

static const TypeInfo riscv_cpu_type_infos[] = {
    DEFINE_CPU(TYPE_RISCV_CPU_ANY,              riscv_any_cpu_init),
#if defined(TARGET_RISCV32)
    DEFINE_CPU(TYPE_RISCV_CPU_RV32GCSU_V1_09_1, rv32gcsu_priv1_09_1_cpu_init),
    DEFINE_CPU(TYPE_RISCV_CPU_RV32GCSU_V1_10_0, rv32gcsu_priv1_10_0_cpu_init),
    DEFINE_CPU(TYPE_RISCV_CPU_RV32IMACU_NOMMU,  rv32imacu_nommu_cpu_init),
    DEFINE_CPU(TYPE_RISCV_CPU_SIFIVE_E31,       rv32imacu_nommu_cpu_init),
    DEFINE_CPU(TYPE_RISCV_CPU_SIFIVE_U34,       rv32gcsu_priv1_10_0_cpu_init),
#elif defined(TARGET_RISCV64)
    DEFINE_CPU(TYPE_RISCV_CPU_RV64GCSU_V1_09_1, rv64gcsu_priv1_09_1_cpu_init),
    DEFINE_CPU(TYPE_RISCV_CPU_RV64GCSU_V1_10_0, rv64gcsu_priv1_10_0_cpu_init),
    DEFINE_CPU(TYPE_RISCV_CPU_RV64IMACU_NOMMU,  rv64imacu_nommu_cpu_init),
    DEFINE_CPU(TYPE_RISCV_CPU_SIFIVE_E51,       rv64imacu_nommu_cpu_init),
    DEFINE_CPU(TYPE_RISCV_CPU_SIFIVE_U54,       rv64gcsu_priv1_10_0_cpu_init),
#endif
    { .name = NULL }
};

void riscv_cpu_register_types(void *opaque) {
    const TypeInfo* cpu_infos = riscv_cpu_type_infos;

    TypeInfo parent_type_info = {
        .name = TYPE_RISCV_CPU,
        .parent = TYPE_CPU,
        .instance_userdata = opaque,
        .instance_size = sizeof(RISCVCPU),
        .instance_init = riscv_cpu_init,
        .abstract = true,
        .class_size = sizeof(RISCVCPUClass),
        .class_init = riscv_cpu_class_init,
    };
    type_register(opaque, &parent_type_info);

    while (cpu_infos->name) {
        type_register(opaque, cpu_infos);
        ++cpu_infos;
    }
}