/*
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2, as
 * published by the Free Software Foundation.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include <linux/errno.h>
#include <linux/err.h>
#include <linux/kvm_host.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <asm/cputype.h>
#include <asm/uaccess.h>
#include <asm/kvm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.h>

#define VM_STAT(x) { #x, offsetof(struct kvm, stat.x), KVM_STAT_VM }
#define VCPU_STAT(x) { #x, offsetof(struct kvm_vcpu, stat.x), KVM_STAT_VCPU }

struct kvm_stats_debugfs_item debugfs_entries[] = {
        { NULL }
};

int kvm_arch_vcpu_setup(struct kvm_vcpu *vcpu)
{
        return 0;
}

static u64 core_reg_offset_from_id(u64 id)
{
        return id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK | KVM_REG_ARM_CORE);
}

static int get_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
        u32 __user *uaddr = (u32 __user *)(long)reg->addr;
        struct kvm_regs *regs = &vcpu->arch.regs;
        u64 off;

        if (KVM_REG_SIZE(reg->id) != 4)
                return -ENOENT;

        /* Our ID is an index into the kvm_regs struct. */
        off = core_reg_offset_from_id(reg->id);
        if (off >= sizeof(*regs) / KVM_REG_SIZE(reg->id))
                return -ENOENT;

        return put_user(((u32 *)regs)[off], uaddr);
}

static int set_core_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
        u32 __user *uaddr = (u32 __user *)(long)reg->addr;
        struct kvm_regs *regs = &vcpu->arch.regs;
        u64 off, val;

        if (KVM_REG_SIZE(reg->id) != 4)
                return -ENOENT;

        /* Our ID is an index into the kvm_regs struct. */
        off = core_reg_offset_from_id(reg->id);
        if (off >= sizeof(*regs) / KVM_REG_SIZE(reg->id))
                return -ENOENT;

        if (get_user(val, uaddr) != 0)
                return -EFAULT;

        if (off == KVM_REG_ARM_CORE_REG(usr_regs.ARM_cpsr)) {
                unsigned long mode = val & MODE_MASK;
                switch (mode) {
                case USR_MODE:
                case FIQ_MODE:
                case IRQ_MODE:
                case SVC_MODE:
                case ABT_MODE:
                case UND_MODE:
                        break;
                default:
                        return -EINVAL;
                }
        }

        ((u32 *)regs)[off] = val;
        return 0;
}

int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
{
        return -EINVAL;
}

int kvm_arch_vcpu_ioctl_set_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
{
        return -EINVAL;
}

static unsigned long num_core_regs(void)
{
        return sizeof(struct kvm_regs) / sizeof(u32);
}

/**
 * kvm_arm_num_regs - how many registers do we present via KVM_GET_ONE_REG
 *
 * This is for all registers.
 */
unsigned long kvm_arm_num_regs(struct kvm_vcpu *vcpu)
{
        return num_core_regs() + kvm_arm_num_coproc_regs(vcpu);
}

/**
 * kvm_arm_copy_reg_indices - get indices of all registers.
 *
 * We do core registers right here, then we apppend coproc regs.
 */
int kvm_arm_copy_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
{
        unsigned int i;
        const u64 core_reg = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_CORE;

        for (i = 0; i < sizeof(struct kvm_regs)/sizeof(u32); i++) {
                if (put_user(core_reg | i, uindices))
                        return -EFAULT;
                uindices++;
        }

        return kvm_arm_copy_coproc_indices(vcpu, uindices);
}

int kvm_arm_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
        /* We currently use nothing arch-specific in upper 32 bits */
        if ((reg->id & ~KVM_REG_SIZE_MASK) >> 32 != KVM_REG_ARM >> 32)
                return -EINVAL;

        /* Register group 16 means we want a core register. */
        if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
                return get_core_reg(vcpu, reg);

        return kvm_arm_coproc_get_reg(vcpu, reg);
}

int kvm_arm_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
        /* We currently use nothing arch-specific in upper 32 bits */
        if ((reg->id & ~KVM_REG_SIZE_MASK) >> 32 != KVM_REG_ARM >> 32)
                return -EINVAL;

        /* Register group 16 means we set a core register. */
        if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_CORE)
                return set_core_reg(vcpu, reg);

        return kvm_arm_coproc_set_reg(vcpu, reg);
}

int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
                                  struct kvm_sregs *sregs)
{
        return -EINVAL;
}

int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
                                  struct kvm_sregs *sregs)
{
        return -EINVAL;
}

int __attribute_const__ kvm_target_cpu(void)
{
        unsigned long implementor = read_cpuid_implementor();
        unsigned long part_number = read_cpuid_part_number();

        if (implementor != ARM_CPU_IMP_ARM)
                return -EINVAL;

        switch (part_number) {
        case ARM_CPU_PART_CORTEX_A15:
                return KVM_ARM_TARGET_CORTEX_A15;
        default:
                return -EINVAL;
        }
}

int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
                        const struct kvm_vcpu_init *init)
{
        unsigned int i;

        /* We can only do a cortex A15 for now. */
        if (init->target != kvm_target_cpu())
                return -EINVAL;

        vcpu->arch.target = init->target;
        bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);

        /* -ENOENT for unknown features, -EINVAL for invalid combinations. */
        for (i = 0; i < sizeof(init->features) * 8; i++) {
                if (test_bit(i, (void *)init->features)) {
                        if (i >= KVM_VCPU_MAX_FEATURES)
                                return -ENOENT;
                        set_bit(i, vcpu->arch.features);
                }
        }

        /* Now we know what it is, we can reset it. */
        return kvm_reset_vcpu(vcpu);
}

int kvm_arch_vcpu_ioctl_get_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
        return -EINVAL;
}

int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
{
        return -EINVAL;
}

int kvm_arch_vcpu_ioctl_translate(struct kvm_vcpu *vcpu,
                                  struct kvm_translation *tr)
{
        return -EINVAL;
}