/*
 *  PowerPC MMU, TLB and BAT emulation helpers for QEMU.
 *
 *  Copyright (c) 2003-2007 Jocelyn Mayer
 *  Copyright (c) 2013 David Gibson, IBM Corporation
 *
 * 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 "helper.h"
#include "sysemu/kvm.h"
#include "kvm_ppc.h"
#include "mmu-hash32.h"

//#define DEBUG_MMU
//#define DEBUG_BAT

#ifdef DEBUG_MMU
#  define LOG_MMU(...) qemu_log(__VA_ARGS__)
#  define LOG_MMU_STATE(env) log_cpu_state((env), 0)
#else
#  define LOG_MMU(...) do { } while (0)
#  define LOG_MMU_STATE(...) do { } while (0)
#endif

#ifdef DEBUG_BATS
#  define LOG_BATS(...) qemu_log(__VA_ARGS__)
#else
#  define LOG_BATS(...) do { } while (0)
#endif

struct mmu_ctx_hash32 {
    hwaddr raddr;      /* Real address              */
    hwaddr eaddr;      /* Effective address         */
    int prot;                      /* Protection bits           */
    hwaddr hash[2];    /* Pagetable hash values     */
    target_ulong ptem;             /* Virtual segment ID | API  */
    int key;                       /* Access key                */
    int nx;                        /* Non-execute area          */
};

#define PTE_CHECK_MASK (TARGET_PAGE_MASK | 0x7B)

static int ppc_hash32_pp_check(int key, int pp, int nx)
{
    int access;

    /* Compute access rights */
    access = 0;
    if (key == 0) {
        switch (pp) {
        case 0x0:
        case 0x1:
        case 0x2:
            access |= PAGE_WRITE;
            /* No break here */
        case 0x3:
            access |= PAGE_READ;
            break;
        }
    } else {
        switch (pp) {
        case 0x0:
            access = 0;
            break;
        case 0x1:
        case 0x3:
            access = PAGE_READ;
            break;
        case 0x2:
            access = PAGE_READ | PAGE_WRITE;
            break;
        }
    }
    if (nx == 0) {
        access |= PAGE_EXEC;
    }

    return access;
}

static int ppc_hash32_check_prot(int prot, int rw, int access_type)
{
    int ret;

    if (access_type == ACCESS_CODE) {
        if (prot & PAGE_EXEC) {
            ret = 0;
        } else {
            ret = -2;
        }
    } else if (rw) {
        if (prot & PAGE_WRITE) {
            ret = 0;
        } else {
            ret = -2;
        }
    } else {
        if (prot & PAGE_READ) {
            ret = 0;
        } else {
            ret = -2;
        }
    }

    return ret;
}

/* Perform BAT hit & translation */
static void hash32_bat_size_prot(CPUPPCState *env, target_ulong *blp,
                                 int *validp, int *protp, target_ulong *BATu,
                                 target_ulong *BATl)
{
    target_ulong bl;
    int pp, valid, prot;

    bl = (*BATu & BATU32_BL) << 15;
    valid = 0;
    prot = 0;
    if (((msr_pr == 0) && (*BATu & BATU32_VS)) ||
        ((msr_pr != 0) && (*BATu & BATU32_VP))) {
        valid = 1;
        pp = *BATl & BATL32_PP;
        if (pp != 0) {
            prot = PAGE_READ | PAGE_EXEC;
            if (pp == 0x2) {
                prot |= PAGE_WRITE;
            }
        }
    }
    *blp = bl;
    *validp = valid;
    *protp = prot;
}

static void hash32_bat_601_size_prot(CPUPPCState *env, target_ulong *blp,
                                     int *validp, int *protp,
                                     target_ulong *BATu, target_ulong *BATl)
{
    target_ulong bl;
    int key, pp, valid, prot;

    bl = (*BATl & BATL32_601_BL) << 17;
    LOG_BATS("b %02x ==> bl " TARGET_FMT_lx " msk " TARGET_FMT_lx "\n",
             (uint8_t)(*BATl & BATL32_601_BL), bl, ~bl);
    prot = 0;
    valid = !!(*BATl & BATL32_601_V);
    if (valid) {
        pp = *BATu & BATU32_601_PP;
        if (msr_pr == 0) {
            key = !!(*BATu & BATU32_601_KS);
        } else {
            key = !!(*BATu & BATU32_601_KP);
        }
        prot = ppc_hash32_pp_check(key, pp, 0);
    }
    *blp = bl;
    *validp = valid;
    *protp = prot;
}

static int ppc_hash32_get_bat(CPUPPCState *env, struct mmu_ctx_hash32 *ctx,
                              target_ulong virtual, int rw, int type)
{
    target_ulong *BATlt, *BATut, *BATu, *BATl;
    target_ulong BEPIl, BEPIu, bl;
    int i, valid, prot;
    int ret = -1;

    LOG_BATS("%s: %cBAT v " TARGET_FMT_lx "\n", __func__,
             type == ACCESS_CODE ? 'I' : 'D', virtual);
    switch (type) {
    case ACCESS_CODE:
        BATlt = env->IBAT[1];
        BATut = env->IBAT[0];
        break;
    default:
        BATlt = env->DBAT[1];
        BATut = env->DBAT[0];
        break;
    }
    for (i = 0; i < env->nb_BATs; i++) {
        BATu = &BATut[i];
        BATl = &BATlt[i];
        BEPIu = *BATu & BATU32_BEPIU;
        BEPIl = *BATu & BATU32_BEPIL;
        if (unlikely(env->mmu_model == POWERPC_MMU_601)) {
            hash32_bat_601_size_prot(env, &bl, &valid, &prot, BATu, BATl);
        } else {
            hash32_bat_size_prot(env, &bl, &valid, &prot, BATu, BATl);
        }
        LOG_BATS("%s: %cBAT%d v " TARGET_FMT_lx " BATu " TARGET_FMT_lx
                 " BATl " TARGET_FMT_lx "\n", __func__,
                 type == ACCESS_CODE ? 'I' : 'D', i, virtual, *BATu, *BATl);
        if ((virtual & BATU32_BEPIU) == BEPIu &&
            ((virtual & BATU32_BEPIL) & ~bl) == BEPIl) {
            /* BAT matches */
            if (valid != 0) {
                /* Get physical address */
                ctx->raddr = (*BATl & BATL32_BRPNU) |
                    ((virtual & BATU32_BEPIL & bl) | (*BATl & BATL32_BRPNL)) |
                    (virtual & 0x0001F000);
                /* Compute access rights */
                ctx->prot = prot;
                ret = ppc_hash32_check_prot(ctx->prot, rw, type);
                if (ret == 0) {
                    LOG_BATS("BAT %d match: r " TARGET_FMT_plx " prot=%c%c\n",
                             i, ctx->raddr, ctx->prot & PAGE_READ ? 'R' : '-',
                             ctx->prot & PAGE_WRITE ? 'W' : '-');
                }
                break;
            }
        }
    }
    if (ret < 0) {
#if defined(DEBUG_BATS)
        if (qemu_log_enabled()) {
            LOG_BATS("no BAT match for " TARGET_FMT_lx ":\n", virtual);
            for (i = 0; i < 4; i++) {
                BATu = &BATut[i];
                BATl = &BATlt[i];
                BEPIu = *BATu & BATU32_BEPIU;
                BEPIl = *BATu & BATU32_BEPIL;
                bl = (*BATu & 0x00001FFC) << 15;
                LOG_BATS("%s: %cBAT%d v " TARGET_FMT_lx " BATu " TARGET_FMT_lx
                         " BATl " TARGET_FMT_lx "\n\t" TARGET_FMT_lx " "
                         TARGET_FMT_lx " " TARGET_FMT_lx "\n",
                         __func__, type == ACCESS_CODE ? 'I' : 'D', i, virtual,
                         *BATu, *BATl, BEPIu, BEPIl, bl);
            }
        }
#endif
    }
    /* No hit */
    return ret;
}

static int pte_check_hash32(struct mmu_ctx_hash32 *ctx, target_ulong pte0,
                            target_ulong pte1, int h, int rw, int type)
{
    target_ulong mmask;
    int access, ret, pp;

    ret = -1;
    /* Check validity and table match */
    if ((pte0 & HPTE32_V_VALID) && (h == !!(pte0 & HPTE32_V_SECONDARY))) {
        /* Check vsid & api */
        mmask = PTE_CHECK_MASK;
        pp = pte1 & HPTE32_R_PP;
        if (HPTE32_V_COMPARE(pte0, ctx->ptem)) {
            if (ctx->raddr != (hwaddr)-1ULL) {
                /* all matches should have equal RPN, WIMG & PP */
                if ((ctx->raddr & mmask) != (pte1 & mmask)) {
                    qemu_log("Bad RPN/WIMG/PP\n");
                    return -3;
                }
            }
            /* Compute access rights */
            access = ppc_hash32_pp_check(ctx->key, pp, ctx->nx);
            /* Keep the matching PTE informations */
            ctx->raddr = pte1;
            ctx->prot = access;
            ret = ppc_hash32_check_prot(ctx->prot, rw, type);
            if (ret == 0) {
                /* Access granted */
                LOG_MMU("PTE access granted !\n");
            } else {
                /* Access right violation */
                LOG_MMU("PTE access rejected\n");
            }
        }
    }

    return ret;
}

static int ppc_hash32_pte_update_flags(struct mmu_ctx_hash32 *ctx, target_ulong *pte1p,
                                       int ret, int rw)
{
    int store = 0;

    /* Update page flags */
    if (!(*pte1p & HPTE32_R_R)) {
        /* Update accessed flag */
        *pte1p |= HPTE32_R_R;
        store = 1;
    }
    if (!(*pte1p & HPTE32_R_C)) {
        if (rw == 1 && ret == 0) {
            /* Update changed flag */
            *pte1p |= HPTE32_R_C;
            store = 1;
        } else {
            /* Force page fault for first write access */
            ctx->prot &= ~PAGE_WRITE;
        }
    }

    return store;
}

hwaddr get_pteg_offset32(CPUPPCState *env, hwaddr hash)
{
    return (hash * HASH_PTEG_SIZE_32) & env->htab_mask;
}

/* PTE table lookup */
static int find_pte32(CPUPPCState *env, struct mmu_ctx_hash32 *ctx, int h,
                      int rw, int type, int target_page_bits)
{
    hwaddr pteg_off;
    target_ulong pte0, pte1;
    int i, good = -1;
    int ret, r;

    ret = -1; /* No entry found */
    pteg_off = get_pteg_offset32(env, ctx->hash[h]);
    for (i = 0; i < HPTES_PER_GROUP; i++) {
        pte0 = ppc_hash32_load_hpte0(env, pteg_off + i*HASH_PTE_SIZE_32);
        pte1 = ppc_hash32_load_hpte1(env, pteg_off + i*HASH_PTE_SIZE_32);
        r = pte_check_hash32(ctx, pte0, pte1, h, rw, type);
        LOG_MMU("Load pte from %08" HWADDR_PRIx " => " TARGET_FMT_lx " "
                TARGET_FMT_lx " %d %d %d " TARGET_FMT_lx "\n",
                pteg_off + (i * 8), pte0, pte1, (int)(pte0 >> 31), h,
                (int)((pte0 >> 6) & 1), ctx->ptem);
        switch (r) {
        case -3:
            /* PTE inconsistency */
            return -1;
        case -2:
            /* Access violation */
            ret = -2;
            good = i;
            break;
        case -1:
        default:
            /* No PTE match */
            break;
        case 0:
            /* access granted */
            /* XXX: we should go on looping to check all PTEs consistency
             *      but if we can speed-up the whole thing as the
             *      result would be undefined if PTEs are not consistent.
             */
            ret = 0;
            good = i;
            goto done;
        }
    }
    if (good != -1) {
    done:
        LOG_MMU("found PTE at addr %08" HWADDR_PRIx " prot=%01x ret=%d\n",
                ctx->raddr, ctx->prot, ret);
        /* Update page flags */
        pte1 = ctx->raddr;
        if (ppc_hash32_pte_update_flags(ctx, &pte1, ret, rw) == 1) {
            ppc_hash32_store_hpte1(env, pteg_off + good * HASH_PTE_SIZE_32,
                                   pte1);
        }
    }

    /* We have a TLB that saves 4K pages, so let's
     * split a huge page to 4k chunks */
    if (target_page_bits != TARGET_PAGE_BITS) {
        ctx->raddr |= (ctx->eaddr & ((1 << target_page_bits) - 1))
                      & TARGET_PAGE_MASK;
    }
    return ret;
}

static int get_segment32(CPUPPCState *env, struct mmu_ctx_hash32 *ctx,
                         target_ulong eaddr, int rw, int type)
{
    hwaddr hash;
    target_ulong vsid;
    int ds, pr, target_page_bits;
    int ret, ret2;
    target_ulong sr, pgidx;

    pr = msr_pr;
    ctx->eaddr = eaddr;

    sr = env->sr[eaddr >> 28];
    ctx->key = (((sr & SR32_KP) && (pr != 0)) ||
                ((sr & SR32_KS) && (pr == 0))) ? 1 : 0;
    ds = !!(sr & SR32_T);
    ctx->nx = !!(sr & SR32_NX);
    vsid = sr & SR32_VSID;
    target_page_bits = TARGET_PAGE_BITS;
    LOG_MMU("Check segment v=" TARGET_FMT_lx " %d " TARGET_FMT_lx " nip="
            TARGET_FMT_lx " lr=" TARGET_FMT_lx
            " ir=%d dr=%d pr=%d %d t=%d\n",
            eaddr, (int)(eaddr >> 28), sr, env->nip, env->lr, (int)msr_ir,
            (int)msr_dr, pr != 0 ? 1 : 0, rw, type);
    pgidx = (eaddr & ~SEGMENT_MASK_256M) >> target_page_bits;
    hash = vsid ^ pgidx;
    ctx->ptem = (vsid << 7) | (pgidx >> 10);

    LOG_MMU("pte segment: key=%d ds %d nx %d vsid " TARGET_FMT_lx "\n",
            ctx->key, ds, ctx->nx, vsid);
    ret = -1;
    if (!ds) {
        /* Check if instruction fetch is allowed, if needed */
        if (type != ACCESS_CODE || ctx->nx == 0) {
            /* Page address translation */
            LOG_MMU("htab_base " TARGET_FMT_plx " htab_mask " TARGET_FMT_plx
                    " hash " TARGET_FMT_plx "\n",
                    env->htab_base, env->htab_mask, hash);
            ctx->hash[0] = hash;
            ctx->hash[1] = ~hash;

            /* Initialize real address with an invalid value */
            ctx->raddr = (hwaddr)-1ULL;
            LOG_MMU("0 htab=" TARGET_FMT_plx "/" TARGET_FMT_plx
                    " vsid=" TARGET_FMT_lx " ptem=" TARGET_FMT_lx
                    " hash=" TARGET_FMT_plx "\n",
                    env->htab_base, env->htab_mask, vsid, ctx->ptem,
                    ctx->hash[0]);
            /* Primary table lookup */
            ret = find_pte32(env, ctx, 0, rw, type, target_page_bits);
            if (ret < 0) {
                /* Secondary table lookup */
                LOG_MMU("1 htab=" TARGET_FMT_plx "/" TARGET_FMT_plx
                        " vsid=" TARGET_FMT_lx " api=" TARGET_FMT_lx
                        " hash=" TARGET_FMT_plx "\n", env->htab_base,
                        env->htab_mask, vsid, ctx->ptem, ctx->hash[1]);
                ret2 = find_pte32(env, ctx, 1, rw, type,
                                  target_page_bits);
                if (ret2 != -1) {
                    ret = ret2;
                }
            }
#if defined(DUMP_PAGE_TABLES)
            if (qemu_log_enabled()) {
                hwaddr curaddr;
                uint32_t a0, a1, a2, a3;

                qemu_log("Page table: " TARGET_FMT_plx " len " TARGET_FMT_plx
                         "\n", sdr, mask + 0x80);
                for (curaddr = sdr; curaddr < (sdr + mask + 0x80);
                     curaddr += 16) {
                    a0 = ldl_phys(curaddr);
                    a1 = ldl_phys(curaddr + 4);
                    a2 = ldl_phys(curaddr + 8);
                    a3 = ldl_phys(curaddr + 12);
                    if (a0 != 0 || a1 != 0 || a2 != 0 || a3 != 0) {
                        qemu_log(TARGET_FMT_plx ": %08x %08x %08x %08x\n",
                                 curaddr, a0, a1, a2, a3);
                    }
                }
            }
#endif
        } else {
            LOG_MMU("No access allowed\n");
            ret = -3;
        }
    } else {
        target_ulong sr;

        LOG_MMU("direct store...\n");
        /* Direct-store segment : absolutely *BUGGY* for now */

        /* Direct-store implies a 32-bit MMU.
         * Check the Segment Register's bus unit ID (BUID).
         */
        sr = env->sr[eaddr >> 28];
        if ((sr & 0x1FF00000) >> 20 == 0x07f) {
            /* Memory-forced I/O controller interface access */
            /* If T=1 and BUID=x'07F', the 601 performs a memory access
             * to SR[28-31] LA[4-31], bypassing all protection mechanisms.
             */
            ctx->raddr = ((sr & 0xF) << 28) | (eaddr & 0x0FFFFFFF);
            ctx->prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
            return 0;
        }

        switch (type) {
        case ACCESS_INT:
            /* Integer load/store : only access allowed */
            break;
        case ACCESS_CODE:
            /* No code fetch is allowed in direct-store areas */
            return -4;
        case ACCESS_FLOAT:
            /* Floating point load/store */
            return -4;
        case ACCESS_RES:
            /* lwarx, ldarx or srwcx. */
            return -4;
        case ACCESS_CACHE:
            /* dcba, dcbt, dcbtst, dcbf, dcbi, dcbst, dcbz, or icbi */
            /* Should make the instruction do no-op.
             * As it already do no-op, it's quite easy :-)
             */
            ctx->raddr = eaddr;
            return 0;
        case ACCESS_EXT:
            /* eciwx or ecowx */
            return -4;
        default:
            qemu_log("ERROR: instruction should not need "
                        "address translation\n");
            return -4;
        }
        if ((rw == 1 || ctx->key != 1) && (rw == 0 || ctx->key != 0)) {
            ctx->raddr = eaddr;
            ret = 2;
        } else {
            ret = -2;
        }
    }

    return ret;
}

static int ppc_hash32_get_physical_address(CPUPPCState *env, struct mmu_ctx_hash32 *ctx,
                                           target_ulong eaddr, int rw,
                                           int access_type)
{
    bool real_mode = (access_type == ACCESS_CODE && msr_ir == 0)
        || (access_type != ACCESS_CODE && msr_dr == 0);

    if (real_mode) {
        ctx->raddr = eaddr;
        ctx->prot = PAGE_READ | PAGE_EXEC | PAGE_WRITE;
        return 0;
    } else {
        int ret = -1;

        /* Try to find a BAT */
        if (env->nb_BATs != 0) {
            ret = ppc_hash32_get_bat(env, ctx, eaddr, rw, access_type);
        }
        if (ret < 0) {
            /* We didn't match any BAT entry or don't have BATs */
            ret = get_segment32(env, ctx, eaddr, rw, access_type);
        }
        return ret;
    }
}

hwaddr ppc_hash32_get_phys_page_debug(CPUPPCState *env, target_ulong addr)
{
    struct mmu_ctx_hash32 ctx;

    if (unlikely(ppc_hash32_get_physical_address(env, &ctx, addr, 0, ACCESS_INT)
                 != 0)) {
        return -1;
    }

    return ctx.raddr & TARGET_PAGE_MASK;
}

int ppc_hash32_handle_mmu_fault(CPUPPCState *env, target_ulong address, int rw,
                                int mmu_idx)
{
    struct mmu_ctx_hash32 ctx;
    int access_type;
    int ret = 0;

    if (rw == 2) {
        /* code access */
        rw = 0;
        access_type = ACCESS_CODE;
    } else {
        /* data access */
        access_type = env->access_type;
    }
    ret = ppc_hash32_get_physical_address(env, &ctx, address, rw, access_type);
    if (ret == 0) {
        tlb_set_page(env, address & TARGET_PAGE_MASK,
                     ctx.raddr & TARGET_PAGE_MASK, ctx.prot,
                     mmu_idx, TARGET_PAGE_SIZE);
        ret = 0;
    } else if (ret < 0) {
        LOG_MMU_STATE(env);
        if (access_type == ACCESS_CODE) {
            switch (ret) {
            case -1:
                /* No matches in page tables or TLB */
                env->exception_index = POWERPC_EXCP_ISI;
                env->error_code = 0x40000000;
                break;
            case -2:
                /* Access rights violation */
                env->exception_index = POWERPC_EXCP_ISI;
                env->error_code = 0x08000000;
                break;
            case -3:
                /* No execute protection violation */
                env->exception_index = POWERPC_EXCP_ISI;
                env->error_code = 0x10000000;
                break;
            case -4:
                /* Direct store exception */
                /* No code fetch is allowed in direct-store areas */
                env->exception_index = POWERPC_EXCP_ISI;
                env->error_code = 0x10000000;
                break;
            }
        } else {
            switch (ret) {
            case -1:
                /* No matches in page tables or TLB */
                env->exception_index = POWERPC_EXCP_DSI;
                env->error_code = 0;
                env->spr[SPR_DAR] = address;
                if (rw == 1) {
                    env->spr[SPR_DSISR] = 0x42000000;
                } else {
                    env->spr[SPR_DSISR] = 0x40000000;
                }
                break;
            case -2:
                /* Access rights violation */
                env->exception_index = POWERPC_EXCP_DSI;
                env->error_code = 0;
                env->spr[SPR_DAR] = address;
                if (rw == 1) {
                    env->spr[SPR_DSISR] = 0x0A000000;
                } else {
                    env->spr[SPR_DSISR] = 0x08000000;
                }
                break;
            case -4:
                /* Direct store exception */
                switch (access_type) {
                case ACCESS_FLOAT:
                    /* Floating point load/store */
                    env->exception_index = POWERPC_EXCP_ALIGN;
                    env->error_code = POWERPC_EXCP_ALIGN_FP;
                    env->spr[SPR_DAR] = address;
                    break;
                case ACCESS_RES:
                    /* lwarx, ldarx or stwcx. */
                    env->exception_index = POWERPC_EXCP_DSI;
                    env->error_code = 0;
                    env->spr[SPR_DAR] = address;
                    if (rw == 1) {
                        env->spr[SPR_DSISR] = 0x06000000;
                    } else {
                        env->spr[SPR_DSISR] = 0x04000000;
                    }
                    break;
                case ACCESS_EXT:
                    /* eciwx or ecowx */
                    env->exception_index = POWERPC_EXCP_DSI;
                    env->error_code = 0;
                    env->spr[SPR_DAR] = address;
                    if (rw == 1) {
                        env->spr[SPR_DSISR] = 0x06100000;
                    } else {
                        env->spr[SPR_DSISR] = 0x04100000;
                    }
                    break;
                default:
                    printf("DSI: invalid exception (%d)\n", ret);
                    env->exception_index = POWERPC_EXCP_PROGRAM;
                    env->error_code =
                        POWERPC_EXCP_INVAL | POWERPC_EXCP_INVAL_INVAL;
                    env->spr[SPR_DAR] = address;
                    break;
                }
                break;
            }
        }
#if 0
        printf("%s: set exception to %d %02x\n", __func__,
               env->exception, env->error_code);
#endif
        ret = 1;
    }

    return ret;
}