/*
 *  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

#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

#define PTE_PTEM_MASK 0x7FFFFFBF
#define PTE_CHECK_MASK (TARGET_PAGE_MASK | 0x7B)

static inline int pte_is_valid_hash32(target_ulong pte0)
{
    return pte0 & 0x80000000 ? 1 : 0;
}

static int pte_check_hash32(mmu_ctx_t *ctx, target_ulong pte0,
                            target_ulong pte1, int h, int rw, int type)
{
    target_ulong ptem, mmask;
    int access, ret, pteh, ptev, pp;

    ret = -1;
    /* Check validity and table match */
    ptev = pte_is_valid_hash32(pte0);
    pteh = (pte0 >> 6) & 1;
    if (ptev && h == pteh) {
        /* Check vsid & api */
        ptem = pte0 & PTE_PTEM_MASK;
        mmask = PTE_CHECK_MASK;
        pp = pte1 & 0x00000003;
        if (ptem == 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 = pp_check(ctx->key, pp, ctx->nx);
            /* Keep the matching PTE informations */
            ctx->raddr = pte1;
            ctx->prot = access;
            ret = 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;
}

/* PTE table lookup */
int find_pte32(CPUPPCState *env, mmu_ctx_t *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_offset(env, ctx->hash[h], HASH_PTE_SIZE_32);
    for (i = 0; i < 8; i++) {
        if (env->external_htab) {
            pte0 = ldl_p(env->external_htab + pteg_off + (i * 8));
            pte1 = ldl_p(env->external_htab + pteg_off + (i * 8) + 4);
        } else {
            pte0 = ldl_phys(env->htab_base + pteg_off + (i * 8));
            pte1 = ldl_phys(env->htab_base + pteg_off + (i * 8) + 4);
        }
        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 (pte_update_flags(ctx, &pte1, ret, rw) == 1) {
            if (env->external_htab) {
                stl_p(env->external_htab + pteg_off + (good * 8) + 4,
                      pte1);
            } else {
                stl_phys_notdirty(env->htab_base + pteg_off +
                                  (good * 8) + 4, 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;
}