/*
 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 * Authors: Rusty Russell <rusty@rustcorp.com.au>
 *          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/mm.h>
#include <linux/kvm_host.h>
#include <linux/uaccess.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_host.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_coproc.h>
#include <asm/cacheflush.h>
#include <asm/cputype.h>
#include <trace/events/kvm.h>
#include <asm/vfp.h>
#include "../vfp/vfpinstr.h"

#include "trace.h"
#include "coproc.h"


/******************************************************************************
 * Co-processor emulation
 *****************************************************************************/

/* 3 bits per cache level, as per CLIDR, but non-existent caches always 0 */
static u32 cache_levels;

/* CSSELR values; used to index KVM_REG_ARM_DEMUX_ID_CCSIDR */
#define CSSELR_MAX 12

int kvm_handle_cp10_id(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
        kvm_inject_undefined(vcpu);
        return 1;
}

int kvm_handle_cp_0_13_access(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
        /*
         * We can get here, if the host has been built without VFPv3 support,
         * but the guest attempted a floating point operation.
         */
        kvm_inject_undefined(vcpu);
        return 1;
}

int kvm_handle_cp14_load_store(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
        kvm_inject_undefined(vcpu);
        return 1;
}

int kvm_handle_cp14_access(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
        kvm_inject_undefined(vcpu);
        return 1;
}

static void reset_mpidr(struct kvm_vcpu *vcpu, const struct coproc_reg *r)
{
        /*
         * Compute guest MPIDR. We build a virtual cluster out of the
         * vcpu_id, but we read the 'U' bit from the underlying
         * hardware directly.
         */
        vcpu->arch.cp15[c0_MPIDR] = ((read_cpuid_mpidr() & MPIDR_SMP_BITMASK) |
                                     ((vcpu->vcpu_id >> 2) << MPIDR_LEVEL_BITS) |
                                     (vcpu->vcpu_id & 3));
}

/* TRM entries A7:4.3.31 A15:4.3.28 - RO WI */
static bool access_actlr(struct kvm_vcpu *vcpu,
                         const struct coproc_params *p,
                         const struct coproc_reg *r)
{
        if (p->is_write)
                return ignore_write(vcpu, p);

        *vcpu_reg(vcpu, p->Rt1) = vcpu->arch.cp15[c1_ACTLR];
        return true;
}

/* TRM entries A7:4.3.56, A15:4.3.60 - R/O. */
static bool access_cbar(struct kvm_vcpu *vcpu,
                        const struct coproc_params *p,
                        const struct coproc_reg *r)
{
        if (p->is_write)
                return write_to_read_only(vcpu, p);
        return read_zero(vcpu, p);
}

/* TRM entries A7:4.3.49, A15:4.3.48 - R/O WI */
static bool access_l2ctlr(struct kvm_vcpu *vcpu,
                          const struct coproc_params *p,
                          const struct coproc_reg *r)
{
        if (p->is_write)
                return ignore_write(vcpu, p);

        *vcpu_reg(vcpu, p->Rt1) = vcpu->arch.cp15[c9_L2CTLR];
        return true;
}

static void reset_l2ctlr(struct kvm_vcpu *vcpu, const struct coproc_reg *r)
{
        u32 l2ctlr, ncores;

        asm volatile("mrc p15, 1, %0, c9, c0, 2\n" : "=r" (l2ctlr));
        l2ctlr &= ~(3 << 24);
        ncores = atomic_read(&vcpu->kvm->online_vcpus) - 1;
        /* How many cores in the current cluster and the next ones */
        ncores -= (vcpu->vcpu_id & ~3);
        /* Cap it to the maximum number of cores in a single cluster */
        ncores = min(ncores, 3U);
        l2ctlr |= (ncores & 3) << 24;

        vcpu->arch.cp15[c9_L2CTLR] = l2ctlr;
}

static void reset_actlr(struct kvm_vcpu *vcpu, const struct coproc_reg *r)
{
        u32 actlr;

        /* ACTLR contains SMP bit: make sure you create all cpus first! */
        asm volatile("mrc p15, 0, %0, c1, c0, 1\n" : "=r" (actlr));
        /* Make the SMP bit consistent with the guest configuration */
        if (atomic_read(&vcpu->kvm->online_vcpus) > 1)
                actlr |= 1U << 6;
        else
                actlr &= ~(1U << 6);

        vcpu->arch.cp15[c1_ACTLR] = actlr;
}

/*
 * TRM entries: A7:4.3.50, A15:4.3.49
 * R/O WI (even if NSACR.NS_L2ERR, a write of 1 is ignored).
 */
static bool access_l2ectlr(struct kvm_vcpu *vcpu,
                           const struct coproc_params *p,
                           const struct coproc_reg *r)
{
        if (p->is_write)
                return ignore_write(vcpu, p);

        *vcpu_reg(vcpu, p->Rt1) = 0;
        return true;
}

/* See note at ARM ARM B1.14.4 */
static bool access_dcsw(struct kvm_vcpu *vcpu,
                        const struct coproc_params *p,
                        const struct coproc_reg *r)
{
        unsigned long val;
        int cpu;

        if (!p->is_write)
                return read_from_write_only(vcpu, p);

        cpu = get_cpu();

        cpumask_setall(&vcpu->arch.require_dcache_flush);
        cpumask_clear_cpu(cpu, &vcpu->arch.require_dcache_flush);

        /* If we were already preempted, take the long way around */
        if (cpu != vcpu->arch.last_pcpu) {
                flush_cache_all();
                goto done;
        }

        val = *vcpu_reg(vcpu, p->Rt1);

        switch (p->CRm) {
        case 6:                 /* Upgrade DCISW to DCCISW, as per HCR.SWIO */
        case 14:                /* DCCISW */
                asm volatile("mcr p15, 0, %0, c7, c14, 2" : : "r" (val));
                break;

        case 10:                /* DCCSW */
                asm volatile("mcr p15, 0, %0, c7, c10, 2" : : "r" (val));
                break;
        }

done:
        put_cpu();

        return true;
}

/*
 * We could trap ID_DFR0 and tell the guest we don't support performance
 * monitoring.  Unfortunately the patch to make the kernel check ID_DFR0 was
 * NAKed, so it will read the PMCR anyway.
 *
 * Therefore we tell the guest we have 0 counters.  Unfortunately, we
 * must always support PMCCNTR (the cycle counter): we just RAZ/WI for
 * all PM registers, which doesn't crash the guest kernel at least.
 */
static bool pm_fake(struct kvm_vcpu *vcpu,
                    const struct coproc_params *p,
                    const struct coproc_reg *r)
{
        if (p->is_write)
                return ignore_write(vcpu, p);
        else
                return read_zero(vcpu, p);
}

#define access_pmcr pm_fake
#define access_pmcntenset pm_fake
#define access_pmcntenclr pm_fake
#define access_pmovsr pm_fake
#define access_pmselr pm_fake
#define access_pmceid0 pm_fake
#define access_pmceid1 pm_fake
#define access_pmccntr pm_fake
#define access_pmxevtyper pm_fake
#define access_pmxevcntr pm_fake
#define access_pmuserenr pm_fake
#define access_pmintenset pm_fake
#define access_pmintenclr pm_fake

/* Architected CP15 registers.
 * CRn denotes the primary register number, but is copied to the CRm in the
 * user space API for 64-bit register access in line with the terminology used
 * in the ARM ARM.
 * Important: Must be sorted ascending by CRn, CRM, Op1, Op2 and with 64-bit
 *            registers preceding 32-bit ones.
 */
static const struct coproc_reg cp15_regs[] = {
        /* MPIDR: we use VMPIDR for guest access. */
        { CRn( 0), CRm( 0), Op1( 0), Op2( 5), is32,
                        NULL, reset_mpidr, c0_MPIDR },

        /* CSSELR: swapped by interrupt.S. */
        { CRn( 0), CRm( 0), Op1( 2), Op2( 0), is32,
                        NULL, reset_unknown, c0_CSSELR },

        /* ACTLR: trapped by HCR.TAC bit. */
        { CRn( 1), CRm( 0), Op1( 0), Op2( 1), is32,
                        access_actlr, reset_actlr, c1_ACTLR },

        /* CPACR: swapped by interrupt.S. */
        { CRn( 1), CRm( 0), Op1( 0), Op2( 2), is32,
                        NULL, reset_val, c1_CPACR, 0x00000000 },

        /* TTBR0/TTBR1: swapped by interrupt.S. */
        { CRm64( 2), Op1( 0), is64, NULL, reset_unknown64, c2_TTBR0 },
        { CRm64( 2), Op1( 1), is64, NULL, reset_unknown64, c2_TTBR1 },

        /* TTBCR: swapped by interrupt.S. */
        { CRn( 2), CRm( 0), Op1( 0), Op2( 2), is32,
                        NULL, reset_val, c2_TTBCR, 0x00000000 },

        /* DACR: swapped by interrupt.S. */
        { CRn( 3), CRm( 0), Op1( 0), Op2( 0), is32,
                        NULL, reset_unknown, c3_DACR },

        /* DFSR/IFSR/ADFSR/AIFSR: swapped by interrupt.S. */
        { CRn( 5), CRm( 0), Op1( 0), Op2( 0), is32,
                        NULL, reset_unknown, c5_DFSR },
        { CRn( 5), CRm( 0), Op1( 0), Op2( 1), is32,
                        NULL, reset_unknown, c5_IFSR },
        { CRn( 5), CRm( 1), Op1( 0), Op2( 0), is32,
                        NULL, reset_unknown, c5_ADFSR },
        { CRn( 5), CRm( 1), Op1( 0), Op2( 1), is32,
                        NULL, reset_unknown, c5_AIFSR },

        /* DFAR/IFAR: swapped by interrupt.S. */
        { CRn( 6), CRm( 0), Op1( 0), Op2( 0), is32,
                        NULL, reset_unknown, c6_DFAR },
        { CRn( 6), CRm( 0), Op1( 0), Op2( 2), is32,
                        NULL, reset_unknown, c6_IFAR },

        /* PAR swapped by interrupt.S */
        { CRm64( 7), Op1( 0), is64, NULL, reset_unknown64, c7_PAR },

        /*
         * DC{C,I,CI}SW operations:
         */
        { CRn( 7), CRm( 6), Op1( 0), Op2( 2), is32, access_dcsw},
        { CRn( 7), CRm(10), Op1( 0), Op2( 2), is32, access_dcsw},
        { CRn( 7), CRm(14), Op1( 0), Op2( 2), is32, access_dcsw},
        /*
         * L2CTLR access (guest wants to know #CPUs).
         */
        { CRn( 9), CRm( 0), Op1( 1), Op2( 2), is32,
                        access_l2ctlr, reset_l2ctlr, c9_L2CTLR },
        { CRn( 9), CRm( 0), Op1( 1), Op2( 3), is32, access_l2ectlr},

        /*
         * Dummy performance monitor implementation.
         */
        { CRn( 9), CRm(12), Op1( 0), Op2( 0), is32, access_pmcr},
        { CRn( 9), CRm(12), Op1( 0), Op2( 1), is32, access_pmcntenset},
        { CRn( 9), CRm(12), Op1( 0), Op2( 2), is32, access_pmcntenclr},
        { CRn( 9), CRm(12), Op1( 0), Op2( 3), is32, access_pmovsr},
        { CRn( 9), CRm(12), Op1( 0), Op2( 5), is32, access_pmselr},
        { CRn( 9), CRm(12), Op1( 0), Op2( 6), is32, access_pmceid0},
        { CRn( 9), CRm(12), Op1( 0), Op2( 7), is32, access_pmceid1},
        { CRn( 9), CRm(13), Op1( 0), Op2( 0), is32, access_pmccntr},
        { CRn( 9), CRm(13), Op1( 0), Op2( 1), is32, access_pmxevtyper},
        { CRn( 9), CRm(13), Op1( 0), Op2( 2), is32, access_pmxevcntr},
        { CRn( 9), CRm(14), Op1( 0), Op2( 0), is32, access_pmuserenr},
        { CRn( 9), CRm(14), Op1( 0), Op2( 1), is32, access_pmintenset},
        { CRn( 9), CRm(14), Op1( 0), Op2( 2), is32, access_pmintenclr},

        /* PRRR/NMRR (aka MAIR0/MAIR1): swapped by interrupt.S. */
        { CRn(10), CRm( 2), Op1( 0), Op2( 0), is32,
                        NULL, reset_unknown, c10_PRRR},
        { CRn(10), CRm( 2), Op1( 0), Op2( 1), is32,
                        NULL, reset_unknown, c10_NMRR},

        /* VBAR: swapped by interrupt.S. */
        { CRn(12), CRm( 0), Op1( 0), Op2( 0), is32,
                        NULL, reset_val, c12_VBAR, 0x00000000 },

        /* CONTEXTIDR/TPIDRURW/TPIDRURO/TPIDRPRW: swapped by interrupt.S. */
        { CRn(13), CRm( 0), Op1( 0), Op2( 1), is32,
                        NULL, reset_val, c13_CID, 0x00000000 },
        { CRn(13), CRm( 0), Op1( 0), Op2( 2), is32,
                        NULL, reset_unknown, c13_TID_URW },
        { CRn(13), CRm( 0), Op1( 0), Op2( 3), is32,
                        NULL, reset_unknown, c13_TID_URO },
        { CRn(13), CRm( 0), Op1( 0), Op2( 4), is32,
                        NULL, reset_unknown, c13_TID_PRIV },

        /* CNTKCTL: swapped by interrupt.S. */
        { CRn(14), CRm( 1), Op1( 0), Op2( 0), is32,
                        NULL, reset_val, c14_CNTKCTL, 0x00000000 },

        /* The Configuration Base Address Register. */
        { CRn(15), CRm( 0), Op1( 4), Op2( 0), is32, access_cbar},
};

/* Target specific emulation tables */
static struct kvm_coproc_target_table *target_tables[KVM_ARM_NUM_TARGETS];

void kvm_register_target_coproc_table(struct kvm_coproc_target_table *table)
{
        unsigned int i;

        for (i = 1; i < table->num; i++)
                BUG_ON(cmp_reg(&table->table[i-1],
                               &table->table[i]) >= 0);

        target_tables[table->target] = table;
}

/* Get specific register table for this target. */
static const struct coproc_reg *get_target_table(unsigned target, size_t *num)
{
        struct kvm_coproc_target_table *table;

        table = target_tables[target];
        *num = table->num;
        return table->table;
}

static const struct coproc_reg *find_reg(const struct coproc_params *params,
                                         const struct coproc_reg table[],
                                         unsigned int num)
{
        unsigned int i;

        for (i = 0; i < num; i++) {
                const struct coproc_reg *r = &table[i];

                if (params->is_64bit != r->is_64)
                        continue;
                if (params->CRn != r->CRn)
                        continue;
                if (params->CRm != r->CRm)
                        continue;
                if (params->Op1 != r->Op1)
                        continue;
                if (params->Op2 != r->Op2)
                        continue;

                return r;
        }
        return NULL;
}

static int emulate_cp15(struct kvm_vcpu *vcpu,
                        const struct coproc_params *params)
{
        size_t num;
        const struct coproc_reg *table, *r;

        trace_kvm_emulate_cp15_imp(params->Op1, params->Rt1, params->CRn,
                                   params->CRm, params->Op2, params->is_write);

        table = get_target_table(vcpu->arch.target, &num);

        /* Search target-specific then generic table. */
        r = find_reg(params, table, num);
        if (!r)
                r = find_reg(params, cp15_regs, ARRAY_SIZE(cp15_regs));

        if (likely(r)) {
                /* If we don't have an accessor, we should never get here! */
                BUG_ON(!r->access);

                if (likely(r->access(vcpu, params, r))) {
                        /* Skip instruction, since it was emulated */
                        kvm_skip_instr(vcpu, kvm_vcpu_trap_il_is32bit(vcpu));
                        return 1;
                }
                /* If access function fails, it should complain. */
        } else {
                kvm_err("Unsupported guest CP15 access at: %08lx\n",
                        *vcpu_pc(vcpu));
                print_cp_instr(params);
        }
        kvm_inject_undefined(vcpu);
        return 1;
}

/**
 * kvm_handle_cp15_64 -- handles a mrrc/mcrr trap on a guest CP15 access
 * @vcpu: The VCPU pointer
 * @run:  The kvm_run struct
 */
int kvm_handle_cp15_64(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
        struct coproc_params params;

        params.CRm = (kvm_vcpu_get_hsr(vcpu) >> 1) & 0xf;
        params.Rt1 = (kvm_vcpu_get_hsr(vcpu) >> 5) & 0xf;
        params.is_write = ((kvm_vcpu_get_hsr(vcpu) & 1) == 0);
        params.is_64bit = true;

        params.Op1 = (kvm_vcpu_get_hsr(vcpu) >> 16) & 0xf;
        params.Op2 = 0;
        params.Rt2 = (kvm_vcpu_get_hsr(vcpu) >> 10) & 0xf;
        params.CRn = 0;

        return emulate_cp15(vcpu, &params);
}

static void reset_coproc_regs(struct kvm_vcpu *vcpu,
                              const struct coproc_reg *table, size_t num)
{
        unsigned long i;

        for (i = 0; i < num; i++)
                if (table[i].reset)
                        table[i].reset(vcpu, &table[i]);
}

/**
 * kvm_handle_cp15_32 -- handles a mrc/mcr trap on a guest CP15 access
 * @vcpu: The VCPU pointer
 * @run:  The kvm_run struct
 */
int kvm_handle_cp15_32(struct kvm_vcpu *vcpu, struct kvm_run *run)
{
        struct coproc_params params;

        params.CRm = (kvm_vcpu_get_hsr(vcpu) >> 1) & 0xf;
        params.Rt1 = (kvm_vcpu_get_hsr(vcpu) >> 5) & 0xf;
        params.is_write = ((kvm_vcpu_get_hsr(vcpu) & 1) == 0);
        params.is_64bit = false;

        params.CRn = (kvm_vcpu_get_hsr(vcpu) >> 10) & 0xf;
        params.Op1 = (kvm_vcpu_get_hsr(vcpu) >> 14) & 0x7;
        params.Op2 = (kvm_vcpu_get_hsr(vcpu) >> 17) & 0x7;
        params.Rt2 = 0;

        return emulate_cp15(vcpu, &params);
}

/******************************************************************************
 * Userspace API
 *****************************************************************************/

static bool index_to_params(u64 id, struct coproc_params *params)
{
        switch (id & KVM_REG_SIZE_MASK) {
        case KVM_REG_SIZE_U32:
                /* Any unused index bits means it's not valid. */
                if (id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK
                           | KVM_REG_ARM_COPROC_MASK
                           | KVM_REG_ARM_32_CRN_MASK
                           | KVM_REG_ARM_CRM_MASK
                           | KVM_REG_ARM_OPC1_MASK
                           | KVM_REG_ARM_32_OPC2_MASK))
                        return false;

                params->is_64bit = false;
                params->CRn = ((id & KVM_REG_ARM_32_CRN_MASK)
                               >> KVM_REG_ARM_32_CRN_SHIFT);
                params->CRm = ((id & KVM_REG_ARM_CRM_MASK)
                               >> KVM_REG_ARM_CRM_SHIFT);
                params->Op1 = ((id & KVM_REG_ARM_OPC1_MASK)
                               >> KVM_REG_ARM_OPC1_SHIFT);
                params->Op2 = ((id & KVM_REG_ARM_32_OPC2_MASK)
                               >> KVM_REG_ARM_32_OPC2_SHIFT);
                return true;
        case KVM_REG_SIZE_U64:
                /* Any unused index bits means it's not valid. */
                if (id & ~(KVM_REG_ARCH_MASK | KVM_REG_SIZE_MASK
                              | KVM_REG_ARM_COPROC_MASK
                              | KVM_REG_ARM_CRM_MASK
                              | KVM_REG_ARM_OPC1_MASK))
                        return false;
                params->is_64bit = true;
                /* CRm to CRn: see cp15_to_index for details */
                params->CRn = ((id & KVM_REG_ARM_CRM_MASK)
                               >> KVM_REG_ARM_CRM_SHIFT);
                params->Op1 = ((id & KVM_REG_ARM_OPC1_MASK)
                               >> KVM_REG_ARM_OPC1_SHIFT);
                params->Op2 = 0;
                params->CRm = 0;
                return true;
        default:
                return false;
        }
}

/* Decode an index value, and find the cp15 coproc_reg entry. */
static const struct coproc_reg *index_to_coproc_reg(struct kvm_vcpu *vcpu,
                                                    u64 id)
{
        size_t num;
        const struct coproc_reg *table, *r;
        struct coproc_params params;

        /* We only do cp15 for now. */
        if ((id & KVM_REG_ARM_COPROC_MASK) >> KVM_REG_ARM_COPROC_SHIFT != 15)
                return NULL;

        if (!index_to_params(id, &params))
                return NULL;

        table = get_target_table(vcpu->arch.target, &num);
        r = find_reg(&params, table, num);
        if (!r)
                r = find_reg(&params, cp15_regs, ARRAY_SIZE(cp15_regs));

        /* Not saved in the cp15 array? */
        if (r && !r->reg)
                r = NULL;

        return r;
}

/*
 * These are the invariant cp15 registers: we let the guest see the host
 * versions of these, so they're part of the guest state.
 *
 * A future CPU may provide a mechanism to present different values to
 * the guest, or a future kvm may trap them.
 */
/* Unfortunately, there's no register-argument for mrc, so generate. */
#define FUNCTION_FOR32(crn, crm, op1, op2, name)                        \
        static void get_##name(struct kvm_vcpu *v,                      \
                               const struct coproc_reg *r)              \
        {                                                               \
                u32 val;                                                \
                                                                        \
                asm volatile("mrc p15, " __stringify(op1)               \
                             ", %0, c" __stringify(crn)                 \
                             ", c" __stringify(crm)                     \
                             ", " __stringify(op2) "\n" : "=r" (val));  \
                ((struct coproc_reg *)r)->val = val;                    \
        }

FUNCTION_FOR32(0, 0, 0, 0, MIDR)
FUNCTION_FOR32(0, 0, 0, 1, CTR)
FUNCTION_FOR32(0, 0, 0, 2, TCMTR)
FUNCTION_FOR32(0, 0, 0, 3, TLBTR)
FUNCTION_FOR32(0, 0, 0, 6, REVIDR)
FUNCTION_FOR32(0, 1, 0, 0, ID_PFR0)
FUNCTION_FOR32(0, 1, 0, 1, ID_PFR1)
FUNCTION_FOR32(0, 1, 0, 2, ID_DFR0)
FUNCTION_FOR32(0, 1, 0, 3, ID_AFR0)
FUNCTION_FOR32(0, 1, 0, 4, ID_MMFR0)
FUNCTION_FOR32(0, 1, 0, 5, ID_MMFR1)
FUNCTION_FOR32(0, 1, 0, 6, ID_MMFR2)
FUNCTION_FOR32(0, 1, 0, 7, ID_MMFR3)
FUNCTION_FOR32(0, 2, 0, 0, ID_ISAR0)
FUNCTION_FOR32(0, 2, 0, 1, ID_ISAR1)
FUNCTION_FOR32(0, 2, 0, 2, ID_ISAR2)
FUNCTION_FOR32(0, 2, 0, 3, ID_ISAR3)
FUNCTION_FOR32(0, 2, 0, 4, ID_ISAR4)
FUNCTION_FOR32(0, 2, 0, 5, ID_ISAR5)
FUNCTION_FOR32(0, 0, 1, 1, CLIDR)
FUNCTION_FOR32(0, 0, 1, 7, AIDR)

/* ->val is filled in by kvm_invariant_coproc_table_init() */
static struct coproc_reg invariant_cp15[] = {
        { CRn( 0), CRm( 0), Op1( 0), Op2( 0), is32, NULL, get_MIDR },
        { CRn( 0), CRm( 0), Op1( 0), Op2( 1), is32, NULL, get_CTR },
        { CRn( 0), CRm( 0), Op1( 0), Op2( 2), is32, NULL, get_TCMTR },
        { CRn( 0), CRm( 0), Op1( 0), Op2( 3), is32, NULL, get_TLBTR },
        { CRn( 0), CRm( 0), Op1( 0), Op2( 6), is32, NULL, get_REVIDR },

        { CRn( 0), CRm( 1), Op1( 0), Op2( 0), is32, NULL, get_ID_PFR0 },
        { CRn( 0), CRm( 1), Op1( 0), Op2( 1), is32, NULL, get_ID_PFR1 },
        { CRn( 0), CRm( 1), Op1( 0), Op2( 2), is32, NULL, get_ID_DFR0 },
        { CRn( 0), CRm( 1), Op1( 0), Op2( 3), is32, NULL, get_ID_AFR0 },
        { CRn( 0), CRm( 1), Op1( 0), Op2( 4), is32, NULL, get_ID_MMFR0 },
        { CRn( 0), CRm( 1), Op1( 0), Op2( 5), is32, NULL, get_ID_MMFR1 },
        { CRn( 0), CRm( 1), Op1( 0), Op2( 6), is32, NULL, get_ID_MMFR2 },
        { CRn( 0), CRm( 1), Op1( 0), Op2( 7), is32, NULL, get_ID_MMFR3 },

        { CRn( 0), CRm( 2), Op1( 0), Op2( 0), is32, NULL, get_ID_ISAR0 },
        { CRn( 0), CRm( 2), Op1( 0), Op2( 1), is32, NULL, get_ID_ISAR1 },
        { CRn( 0), CRm( 2), Op1( 0), Op2( 2), is32, NULL, get_ID_ISAR2 },
        { CRn( 0), CRm( 2), Op1( 0), Op2( 3), is32, NULL, get_ID_ISAR3 },
        { CRn( 0), CRm( 2), Op1( 0), Op2( 4), is32, NULL, get_ID_ISAR4 },
        { CRn( 0), CRm( 2), Op1( 0), Op2( 5), is32, NULL, get_ID_ISAR5 },

        { CRn( 0), CRm( 0), Op1( 1), Op2( 1), is32, NULL, get_CLIDR },
        { CRn( 0), CRm( 0), Op1( 1), Op2( 7), is32, NULL, get_AIDR },
};

static int reg_from_user(void *val, const void __user *uaddr, u64 id)
{
        /* This Just Works because we are little endian. */
        if (copy_from_user(val, uaddr, KVM_REG_SIZE(id)) != 0)
                return -EFAULT;
        return 0;
}

static int reg_to_user(void __user *uaddr, const void *val, u64 id)
{
        /* This Just Works because we are little endian. */
        if (copy_to_user(uaddr, val, KVM_REG_SIZE(id)) != 0)
                return -EFAULT;
        return 0;
}

static int get_invariant_cp15(u64 id, void __user *uaddr)
{
        struct coproc_params params;
        const struct coproc_reg *r;

        if (!index_to_params(id, &params))
                return -ENOENT;

        r = find_reg(&params, invariant_cp15, ARRAY_SIZE(invariant_cp15));
        if (!r)
                return -ENOENT;

        return reg_to_user(uaddr, &r->val, id);
}

static int set_invariant_cp15(u64 id, void __user *uaddr)
{
        struct coproc_params params;
        const struct coproc_reg *r;
        int err;
        u64 val = 0; /* Make sure high bits are 0 for 32-bit regs */

        if (!index_to_params(id, &params))
                return -ENOENT;
        r = find_reg(&params, invariant_cp15, ARRAY_SIZE(invariant_cp15));
        if (!r)
                return -ENOENT;

        err = reg_from_user(&val, uaddr, id);
        if (err)
                return err;

        /* This is what we mean by invariant: you can't change it. */
        if (r->val != val)
                return -EINVAL;

        return 0;
}

static bool is_valid_cache(u32 val)
{
        u32 level, ctype;

        if (val >= CSSELR_MAX)
                return -ENOENT;

        /* Bottom bit is Instruction or Data bit.  Next 3 bits are level. */
        level = (val >> 1);
        ctype = (cache_levels >> (level * 3)) & 7;

        switch (ctype) {
        case 0: /* No cache */
                return false;
        case 1: /* Instruction cache only */
                return (val & 1);
        case 2: /* Data cache only */
        case 4: /* Unified cache */
                return !(val & 1);
        case 3: /* Separate instruction and data caches */
                return true;
        default: /* Reserved: we can't know instruction or data. */
                return false;
        }
}

/* Which cache CCSIDR represents depends on CSSELR value. */
static u32 get_ccsidr(u32 csselr)
{
        u32 ccsidr;

        /* Make sure noone else changes CSSELR during this! */
        local_irq_disable();
        /* Put value into CSSELR */
        asm volatile("mcr p15, 2, %0, c0, c0, 0" : : "r" (csselr));
        isb();
        /* Read result out of CCSIDR */
        asm volatile("mrc p15, 1, %0, c0, c0, 0" : "=r" (ccsidr));
        local_irq_enable();

        return ccsidr;
}

static int demux_c15_get(u64 id, void __user *uaddr)
{
        u32 val;
        u32 __user *uval = uaddr;

        /* Fail if we have unknown bits set. */
        if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
                   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
                return -ENOENT;

        switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
        case KVM_REG_ARM_DEMUX_ID_CCSIDR:
                if (KVM_REG_SIZE(id) != 4)
                        return -ENOENT;
                val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
                        >> KVM_REG_ARM_DEMUX_VAL_SHIFT;
                if (!is_valid_cache(val))
                        return -ENOENT;

                return put_user(get_ccsidr(val), uval);
        default:
                return -ENOENT;
        }
}

static int demux_c15_set(u64 id, void __user *uaddr)
{
        u32 val, newval;
        u32 __user *uval = uaddr;

        /* Fail if we have unknown bits set. */
        if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
                   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
                return -ENOENT;

        switch (id & KVM_REG_ARM_DEMUX_ID_MASK) {
        case KVM_REG_ARM_DEMUX_ID_CCSIDR:
                if (KVM_REG_SIZE(id) != 4)
                        return -ENOENT;
                val = (id & KVM_REG_ARM_DEMUX_VAL_MASK)
                        >> KVM_REG_ARM_DEMUX_VAL_SHIFT;
                if (!is_valid_cache(val))
                        return -ENOENT;

                if (get_user(newval, uval))
                        return -EFAULT;

                /* This is also invariant: you can't change it. */
                if (newval != get_ccsidr(val))
                        return -EINVAL;
                return 0;
        default:
                return -ENOENT;
        }
}

#ifdef CONFIG_VFPv3
static const int vfp_sysregs[] = { KVM_REG_ARM_VFP_FPEXC,
                                   KVM_REG_ARM_VFP_FPSCR,
                                   KVM_REG_ARM_VFP_FPINST,
                                   KVM_REG_ARM_VFP_FPINST2,
                                   KVM_REG_ARM_VFP_MVFR0,
                                   KVM_REG_ARM_VFP_MVFR1,
                                   KVM_REG_ARM_VFP_FPSID };

static unsigned int num_fp_regs(void)
{
        if (((fmrx(MVFR0) & MVFR0_A_SIMD_MASK) >> MVFR0_A_SIMD_BIT) == 2)
                return 32;
        else
                return 16;
}

static unsigned int num_vfp_regs(void)
{
        /* Normal FP regs + control regs. */
        return num_fp_regs() + ARRAY_SIZE(vfp_sysregs);
}

static int copy_vfp_regids(u64 __user *uindices)
{
        unsigned int i;
        const u64 u32reg = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_VFP;
        const u64 u64reg = KVM_REG_ARM | KVM_REG_SIZE_U64 | KVM_REG_ARM_VFP;

        for (i = 0; i < num_fp_regs(); i++) {
                if (put_user((u64reg | KVM_REG_ARM_VFP_BASE_REG) + i,
                             uindices))
                        return -EFAULT;
                uindices++;
        }

        for (i = 0; i < ARRAY_SIZE(vfp_sysregs); i++) {
                if (put_user(u32reg | vfp_sysregs[i], uindices))
                        return -EFAULT;
                uindices++;
        }

        return num_vfp_regs();
}

static int vfp_get_reg(const struct kvm_vcpu *vcpu, u64 id, void __user *uaddr)
{
        u32 vfpid = (id & KVM_REG_ARM_VFP_MASK);
        u32 val;

        /* Fail if we have unknown bits set. */
        if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
                   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
                return -ENOENT;

        if (vfpid < num_fp_regs()) {
                if (KVM_REG_SIZE(id) != 8)
                        return -ENOENT;
                return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpregs[vfpid],
                                   id);
        }

        /* FP control registers are all 32 bit. */
        if (KVM_REG_SIZE(id) != 4)
                return -ENOENT;

        switch (vfpid) {
        case KVM_REG_ARM_VFP_FPEXC:
                return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpexc, id);
        case KVM_REG_ARM_VFP_FPSCR:
                return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpscr, id);
        case KVM_REG_ARM_VFP_FPINST:
                return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpinst, id);
        case KVM_REG_ARM_VFP_FPINST2:
                return reg_to_user(uaddr, &vcpu->arch.vfp_guest.fpinst2, id);
        case KVM_REG_ARM_VFP_MVFR0:
                val = fmrx(MVFR0);
                return reg_to_user(uaddr, &val, id);
        case KVM_REG_ARM_VFP_MVFR1:
                val = fmrx(MVFR1);
                return reg_to_user(uaddr, &val, id);
        case KVM_REG_ARM_VFP_FPSID:
                val = fmrx(FPSID);
                return reg_to_user(uaddr, &val, id);
        default:
                return -ENOENT;
        }
}

static int vfp_set_reg(struct kvm_vcpu *vcpu, u64 id, const void __user *uaddr)
{
        u32 vfpid = (id & KVM_REG_ARM_VFP_MASK);
        u32 val;

        /* Fail if we have unknown bits set. */
        if (id & ~(KVM_REG_ARCH_MASK|KVM_REG_SIZE_MASK|KVM_REG_ARM_COPROC_MASK
                   | ((1 << KVM_REG_ARM_COPROC_SHIFT)-1)))
                return -ENOENT;

        if (vfpid < num_fp_regs()) {
                if (KVM_REG_SIZE(id) != 8)
                        return -ENOENT;
                return reg_from_user(&vcpu->arch.vfp_guest.fpregs[vfpid],
                                     uaddr, id);
        }

        /* FP control registers are all 32 bit. */
        if (KVM_REG_SIZE(id) != 4)
                return -ENOENT;

        switch (vfpid) {
        case KVM_REG_ARM_VFP_FPEXC:
                return reg_from_user(&vcpu->arch.vfp_guest.fpexc, uaddr, id);
        case KVM_REG_ARM_VFP_FPSCR:
                return reg_from_user(&vcpu->arch.vfp_guest.fpscr, uaddr, id);
        case KVM_REG_ARM_VFP_FPINST:
                return reg_from_user(&vcpu->arch.vfp_guest.fpinst, uaddr, id);
        case KVM_REG_ARM_VFP_FPINST2:
                return reg_from_user(&vcpu->arch.vfp_guest.fpinst2, uaddr, id);
        /* These are invariant. */
        case KVM_REG_ARM_VFP_MVFR0:
                if (reg_from_user(&val, uaddr, id))
                        return -EFAULT;
                if (val != fmrx(MVFR0))
                        return -EINVAL;
                return 0;
        case KVM_REG_ARM_VFP_MVFR1:
                if (reg_from_user(&val, uaddr, id))
                        return -EFAULT;
                if (val != fmrx(MVFR1))
                        return -EINVAL;
                return 0;
        case KVM_REG_ARM_VFP_FPSID:
                if (reg_from_user(&val, uaddr, id))
                        return -EFAULT;
                if (val != fmrx(FPSID))
                        return -EINVAL;
                return 0;
        default:
                return -ENOENT;
        }
}
#else /* !CONFIG_VFPv3 */
static unsigned int num_vfp_regs(void)
{
        return 0;
}

static int copy_vfp_regids(u64 __user *uindices)
{
        return 0;
}

static int vfp_get_reg(const struct kvm_vcpu *vcpu, u64 id, void __user *uaddr)
{
        return -ENOENT;
}

static int vfp_set_reg(struct kvm_vcpu *vcpu, u64 id, const void __user *uaddr)
{
        return -ENOENT;
}
#endif /* !CONFIG_VFPv3 */

int kvm_arm_coproc_get_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
        const struct coproc_reg *r;
        void __user *uaddr = (void __user *)(long)reg->addr;

        if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
                return demux_c15_get(reg->id, uaddr);

        if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_VFP)
                return vfp_get_reg(vcpu, reg->id, uaddr);

        r = index_to_coproc_reg(vcpu, reg->id);
        if (!r)
                return get_invariant_cp15(reg->id, uaddr);

        /* Note: copies two regs if size is 64 bit. */
        return reg_to_user(uaddr, &vcpu->arch.cp15[r->reg], reg->id);
}

int kvm_arm_coproc_set_reg(struct kvm_vcpu *vcpu, const struct kvm_one_reg *reg)
{
        const struct coproc_reg *r;
        void __user *uaddr = (void __user *)(long)reg->addr;

        if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_DEMUX)
                return demux_c15_set(reg->id, uaddr);

        if ((reg->id & KVM_REG_ARM_COPROC_MASK) == KVM_REG_ARM_VFP)
                return vfp_set_reg(vcpu, reg->id, uaddr);

        r = index_to_coproc_reg(vcpu, reg->id);
        if (!r)
                return set_invariant_cp15(reg->id, uaddr);

        /* Note: copies two regs if size is 64 bit */
        return reg_from_user(&vcpu->arch.cp15[r->reg], uaddr, reg->id);
}

static unsigned int num_demux_regs(void)
{
        unsigned int i, count = 0;

        for (i = 0; i < CSSELR_MAX; i++)
                if (is_valid_cache(i))
                        count++;

        return count;
}

static int write_demux_regids(u64 __user *uindices)
{
        u64 val = KVM_REG_ARM | KVM_REG_SIZE_U32 | KVM_REG_ARM_DEMUX;
        unsigned int i;

        val |= KVM_REG_ARM_DEMUX_ID_CCSIDR;
        for (i = 0; i < CSSELR_MAX; i++) {
                if (!is_valid_cache(i))
                        continue;
                if (put_user(val | i, uindices))
                        return -EFAULT;
                uindices++;
        }
        return 0;
}

static u64 cp15_to_index(const struct coproc_reg *reg)
{
        u64 val = KVM_REG_ARM | (15 << KVM_REG_ARM_COPROC_SHIFT);
        if (reg->is_64) {
                val |= KVM_REG_SIZE_U64;
                val |= (reg->Op1 << KVM_REG_ARM_OPC1_SHIFT);
                /*
                 * CRn always denotes the primary coproc. reg. nr. for the
                 * in-kernel representation, but the user space API uses the
                 * CRm for the encoding, because it is modelled after the
                 * MRRC/MCRR instructions: see the ARM ARM rev. c page
                 * B3-1445
                 */
                val |= (reg->CRn << KVM_REG_ARM_CRM_SHIFT);
        } else {
                val |= KVM_REG_SIZE_U32;
                val |= (reg->Op1 << KVM_REG_ARM_OPC1_SHIFT);
                val |= (reg->Op2 << KVM_REG_ARM_32_OPC2_SHIFT);
                val |= (reg->CRm << KVM_REG_ARM_CRM_SHIFT);
                val |= (reg->CRn << KVM_REG_ARM_32_CRN_SHIFT);
        }
        return val;
}

static bool copy_reg_to_user(const struct coproc_reg *reg, u64 __user **uind)
{
        if (!*uind)
                return true;

        if (put_user(cp15_to_index(reg), *uind))
                return false;

        (*uind)++;
        return true;
}

/* Assumed ordered tables, see kvm_coproc_table_init. */
static int walk_cp15(struct kvm_vcpu *vcpu, u64 __user *uind)
{
        const struct coproc_reg *i1, *i2, *end1, *end2;
        unsigned int total = 0;
        size_t num;

        /* We check for duplicates here, to allow arch-specific overrides. */
        i1 = get_target_table(vcpu->arch.target, &num);
        end1 = i1 + num;
        i2 = cp15_regs;
        end2 = cp15_regs + ARRAY_SIZE(cp15_regs);

        BUG_ON(i1 == end1 || i2 == end2);

        /* Walk carefully, as both tables may refer to the same register. */
        while (i1 || i2) {
                int cmp = cmp_reg(i1, i2);
                /* target-specific overrides generic entry. */
                if (cmp <= 0) {
                        /* Ignore registers we trap but don't save. */
                        if (i1->reg) {
                                if (!copy_reg_to_user(i1, &uind))
                                        return -EFAULT;
                                total++;
                        }
                } else {
                        /* Ignore registers we trap but don't save. */
                        if (i2->reg) {
                                if (!copy_reg_to_user(i2, &uind))
                                        return -EFAULT;
                                total++;
                        }
                }

                if (cmp <= 0 && ++i1 == end1)
                        i1 = NULL;
                if (cmp >= 0 && ++i2 == end2)
                        i2 = NULL;
        }
        return total;
}

unsigned long kvm_arm_num_coproc_regs(struct kvm_vcpu *vcpu)
{
        return ARRAY_SIZE(invariant_cp15)
                + num_demux_regs()
                + num_vfp_regs()
                + walk_cp15(vcpu, (u64 __user *)NULL);
}

int kvm_arm_copy_coproc_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
{
        unsigned int i;
        int err;

        /* Then give them all the invariant registers' indices. */
        for (i = 0; i < ARRAY_SIZE(invariant_cp15); i++) {
                if (put_user(cp15_to_index(&invariant_cp15[i]), uindices))
                        return -EFAULT;
                uindices++;
        }

        err = walk_cp15(vcpu, uindices);
        if (err < 0)
                return err;
        uindices += err;

        err = copy_vfp_regids(uindices);
        if (err < 0)
                return err;
        uindices += err;

        return write_demux_regids(uindices);
}

void kvm_coproc_table_init(void)
{
        unsigned int i;

        /* Make sure tables are unique and in order. */
        for (i = 1; i < ARRAY_SIZE(cp15_regs); i++)
                BUG_ON(cmp_reg(&cp15_regs[i-1], &cp15_regs[i]) >= 0);

        /* We abuse the reset function to overwrite the table itself. */
        for (i = 0; i < ARRAY_SIZE(invariant_cp15); i++)
                invariant_cp15[i].reset(NULL, &invariant_cp15[i]);

        /*
         * CLIDR format is awkward, so clean it up.  See ARM B4.1.20:
         *
         *   If software reads the Cache Type fields from Ctype1
         *   upwards, once it has seen a value of 0b000, no caches
         *   exist at further-out levels of the hierarchy. So, for
         *   example, if Ctype3 is the first Cache Type field with a
         *   value of 0b000, the values of Ctype4 to Ctype7 must be
         *   ignored.
         */
        asm volatile("mrc p15, 1, %0, c0, c0, 1" : "=r" (cache_levels));
        for (i = 0; i < 7; i++)
                if (((cache_levels >> (i*3)) & 7) == 0)
                        break;
        /* Clear all higher bits. */
        cache_levels &= (1 << (i*3))-1;
}

/**
 * kvm_reset_coprocs - sets cp15 registers to reset value
 * @vcpu: The VCPU pointer
 *
 * This function finds the right table above and sets the registers on the
 * virtual CPU struct to their architecturally defined reset values.
 */
void kvm_reset_coprocs(struct kvm_vcpu *vcpu)
{
        size_t num;
        const struct coproc_reg *table;

        /* Catch someone adding a register without putting in reset entry. */
        memset(vcpu->arch.cp15, 0x42, sizeof(vcpu->arch.cp15));

        /* Generic chip reset first (so target could override). */
        reset_coproc_regs(vcpu, cp15_regs, ARRAY_SIZE(cp15_regs));

        table = get_target_table(vcpu->arch.target, &num);
        reset_coproc_regs(vcpu, table, num);

        for (num = 1; num < NR_CP15_REGS; num++)
                if (vcpu->arch.cp15[num] == 0x42424242)
                        panic("Didn't reset vcpu->arch.cp15[%zi]", num);
}