Archipelago » qemu

/*

 *  MIPS emulation helpers for qemu.

 * 

 *  Copyright (c) 2004-2005 Jocelyn Mayer

 *

 * 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, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include <stdarg.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <inttypes.h>

#include <signal.h>

#include <assert.h>

#include "cpu.h"

#include "exec-all.h"

enum {

    TLBRET_DIRTY = -4,

    TLBRET_INVALID = -3,

    TLBRET_NOMATCH = -2,

    TLBRET_BADADDR = -1,

    TLBRET_MATCH = 0

};

/* MIPS32 4K MMU emulation */

#ifdef MIPS_USES_R4K_TLB

static int map_address (CPUState *env, target_ulong *physical, int *prot,

                        target_ulong address, int rw, int access_type)

{

    target_ulong tag = address & (TARGET_PAGE_MASK << 1);

    uint8_t ASID = env->CP0_EntryHi & 0xFF;

    tlb_t *tlb;

    int i, n;

    for (i = 0; i < env->tlb_in_use; i++) {

        tlb = &env->tlb[i];

        /* Check ASID, virtual page number & size */

        if ((tlb->G == 1 || tlb->ASID == ASID) &&

            tlb->VPN == tag && address < tlb->end2) {

            /* TLB match */

            n = (address >> TARGET_PAGE_BITS) & 1;

            /* Check access rights */

           if (!(n ? tlb->V1 : tlb->V0))

                return TLBRET_INVALID;

           if (rw == 0 || (n ? tlb->D1 : tlb->D0)) {

                *physical = tlb->PFN[n] | (address & ~TARGET_PAGE_MASK);

                *prot = PAGE_READ;

                if (n ? tlb->D1 : tlb->D0)

                    *prot |= PAGE_WRITE;

                return TLBRET_MATCH;

            }

            return TLBRET_DIRTY;

        }

    }

    return TLBRET_NOMATCH;

}

#endif

static int get_physical_address (CPUState *env, target_ulong *physical,

                                int *prot, target_ulong address,

                                int rw, int access_type)

{

    /* User mode can only access useg */

    int user_mode = (env->hflags & MIPS_HFLAG_MODE) == MIPS_HFLAG_UM;

    int ret = TLBRET_MATCH;

#if 0

    if (logfile) {

        fprintf(logfile, "user mode %d h %08x\n",

                user_mode, env->hflags);

    }

#endif

    if (user_mode && address > 0x7FFFFFFFUL)

        return TLBRET_BADADDR;

    if (address < SIGN_EXTEND32(0x80000000UL)) {

        if (!(env->hflags & MIPS_HFLAG_ERL)) {

#ifdef MIPS_USES_R4K_TLB

            ret = map_address(env, physical, prot, address, rw, access_type);

#else

            *physical = address + 0x40000000UL;

            *prot = PAGE_READ | PAGE_WRITE;

#endif

        } else {

            *physical = address;

            *prot = PAGE_READ | PAGE_WRITE;

        }

    } else if (address < SIGN_EXTEND32(0xA0000000UL)) {

        /* kseg0 */

        /* XXX: check supervisor mode */

        *physical = address - SIGN_EXTEND32(0x80000000UL);

        *prot = PAGE_READ | PAGE_WRITE;

    } else if (address < SIGN_EXTEND32(0xC0000000UL)) {

        /* kseg1 */

        /* XXX: check supervisor mode */

        *physical = address - SIGN_EXTEND32(0xA0000000UL);

        *prot = PAGE_READ | PAGE_WRITE;

    } else if (address < SIGN_EXTEND32(0xE0000000UL)) {

        /* kseg2 */

#ifdef MIPS_USES_R4K_TLB

        ret = map_address(env, physical, prot, address, rw, access_type);

#else

        *physical = address;

        *prot = PAGE_READ | PAGE_WRITE;

#endif

    } else {

        /* kseg3 */

        /* XXX: check supervisor mode */

        /* XXX: debug segment is not emulated */

#ifdef MIPS_USES_R4K_TLB

        ret = map_address(env, physical, prot, address, rw, access_type);

#else

        *physical = address;

        *prot = PAGE_READ | PAGE_WRITE;

#endif

    }

#if 0

    if (logfile) {

        fprintf(logfile, TLSZ " %d %d => " TLSZ " %d (%d)\n",

                address, rw, access_type, *physical, *prot, ret);

    }

#endif

    return ret;

}

#if defined(CONFIG_USER_ONLY) 

target_ulong cpu_get_phys_page_debug(CPUState *env, target_ulong addr)

{

    return addr;

}

#else

target_ulong cpu_get_phys_page_debug(CPUState *env, target_ulong addr)

{

    target_ulong phys_addr;

    int prot;

    if (get_physical_address(env, &phys_addr, &prot, addr, 0, ACCESS_INT) != 0)

        return -1;

    return phys_addr;

}

void cpu_mips_init_mmu (CPUState *env)

{

}

#endif /* !defined(CONFIG_USER_ONLY) */

int cpu_mips_handle_mmu_fault (CPUState *env, target_ulong address, int rw,

                               int is_user, int is_softmmu)

{

    target_ulong physical;

    int prot;

    int exception = 0, error_code = 0;

    int access_type;

    int ret = 0;

    if (logfile) {

#if 0

        cpu_dump_state(env, logfile, fprintf, 0);

#endif

        fprintf(logfile, "%s pc " TLSZ " ad " TLSZ " rw %d is_user %d smmu %d\n",

                __func__, env->PC, address, rw, is_user, is_softmmu);

    }

    rw &= 1;

    /* data access */

    /* XXX: put correct access by using cpu_restore_state()

       correctly */

    access_type = ACCESS_INT;

    if (env->user_mode_only) {

        /* user mode only emulation */

        ret = TLBRET_NOMATCH;

        goto do_fault;

    }

    ret = get_physical_address(env, &physical, &prot,

                               address, rw, access_type);

    if (logfile) {

        fprintf(logfile, "%s address=" TLSZ " ret %d physical " TLSZ " prot %d\n",

                __func__, address, ret, physical, prot);

    }

    if (ret == TLBRET_MATCH) {

       ret = tlb_set_page(env, address & TARGET_PAGE_MASK,

                          physical & TARGET_PAGE_MASK, prot,

                          is_user, is_softmmu);

    } else if (ret < 0) {

    do_fault:

        switch (ret) {

        default:

        case TLBRET_BADADDR:

            /* Reference to kernel address from user mode or supervisor mode */

            /* Reference to supervisor address from user mode */

            if (rw)

                exception = EXCP_AdES;

            else

                exception = EXCP_AdEL;

            break;

        case TLBRET_NOMATCH:

            /* No TLB match for a mapped address */

            if (rw)

                exception = EXCP_TLBS;

            else

                exception = EXCP_TLBL;

            error_code = 1;

            break;

        case TLBRET_INVALID:

            /* TLB match with no valid bit */

            if (rw)

                exception = EXCP_TLBS;

            else

                exception = EXCP_TLBL;

            break;

        case TLBRET_DIRTY:

            /* TLB match but 'D' bit is cleared */

            exception = EXCP_LTLBL;

            break;

        }

        /* Raise exception */

        env->CP0_BadVAddr = address;

        env->CP0_Context = (env->CP0_Context & 0xff800000) |

                           ((address >> 9) &   0x007ffff0);

        env->CP0_EntryHi =

            (env->CP0_EntryHi & 0xFF) | (address & (TARGET_PAGE_MASK << 1));

        env->exception_index = exception;

        env->error_code = error_code;

        ret = 1;

    }

    return ret;

}

#if defined(CONFIG_USER_ONLY)

void do_interrupt (CPUState *env)

{

    env->exception_index = EXCP_NONE;

}

#else

void do_interrupt (CPUState *env)

{

    target_ulong offset;

    int cause = -1;

    if (logfile && env->exception_index != EXCP_EXT_INTERRUPT) {

        fprintf(logfile, "%s enter: PC " TLSZ " EPC " TLSZ " cause %d excp %d\n",

                __func__, env->PC, env->CP0_EPC, cause, env->exception_index);

    }

    if (env->exception_index == EXCP_EXT_INTERRUPT &&

        (env->hflags & MIPS_HFLAG_DM))

        env->exception_index = EXCP_DINT;

    offset = 0x180;

    switch (env->exception_index) {

    case EXCP_DSS:

        env->CP0_Debug |= 1 << CP0DB_DSS;

        /* Debug single step cannot be raised inside a delay slot and

         * resume will always occur on the next instruction

         * (but we assume the pc has always been updated during

         *  code translation).

         */

        env->CP0_DEPC = env->PC;

        goto enter_debug_mode;

    case EXCP_DINT:

        env->CP0_Debug |= 1 << CP0DB_DINT;

        goto set_DEPC;

    case EXCP_DIB:

        env->CP0_Debug |= 1 << CP0DB_DIB;

        goto set_DEPC;

    case EXCP_DBp:

        env->CP0_Debug |= 1 << CP0DB_DBp;

        goto set_DEPC;

    case EXCP_DDBS:

        env->CP0_Debug |= 1 << CP0DB_DDBS;

        goto set_DEPC;

    case EXCP_DDBL:

        env->CP0_Debug |= 1 << CP0DB_DDBL;

        goto set_DEPC;

    set_DEPC:

        if (env->hflags & MIPS_HFLAG_BMASK) {

            /* If the exception was raised from a delay slot,

               come back to the jump.  */

            env->CP0_DEPC = env->PC - 4;

            env->hflags &= ~MIPS_HFLAG_BMASK;

        } else {

            env->CP0_DEPC = env->PC;

        }

    enter_debug_mode:

        env->hflags |= MIPS_HFLAG_DM;

        /* EJTAG probe trap enable is not implemented... */

        env->PC = SIGN_EXTEND32(0xBFC00480);

        break;

    case EXCP_RESET:

        cpu_reset(env);

        break;

    case EXCP_SRESET:

        env->CP0_Status = (1 << CP0St_SR);

        env->CP0_WatchLo = 0;

        goto set_error_EPC;

    case EXCP_NMI:

        env->CP0_Status = (1 << CP0St_NMI);

    set_error_EPC:

        if (env->hflags & MIPS_HFLAG_BMASK) {

            /* If the exception was raised from a delay slot,

               come back to the jump.  */

            env->CP0_ErrorEPC = env->PC - 4;

            env->hflags &= ~MIPS_HFLAG_BMASK;

        } else {

            env->CP0_ErrorEPC = env->PC;

        }

        env->hflags |= MIPS_HFLAG_ERL;

        env->CP0_Status |= (1 << CP0St_ERL) | (1 << CP0St_BEV);

        env->PC = SIGN_EXTEND32(0xBFC00000);

        break;

    case EXCP_MCHECK:

        cause = 24;

        goto set_EPC;

    case EXCP_EXT_INTERRUPT:

        cause = 0;

        if (env->CP0_Cause & (1 << CP0Ca_IV))

            offset = 0x200;

        goto set_EPC;

    case EXCP_DWATCH:

        cause = 23;

        /* XXX: TODO: manage defered watch exceptions */

        goto set_EPC;

    case EXCP_AdEL:

    case EXCP_AdES:

        cause = 4;

        goto set_EPC;

    case EXCP_TLBL:

        cause = 2;

        if (env->error_code == 1 && !(env->hflags & MIPS_HFLAG_EXL))

            offset = 0x000;

        goto set_EPC;

    case EXCP_IBE:

        cause = 6;

        goto set_EPC;

    case EXCP_DBE:

        cause = 7;

        goto set_EPC;

    case EXCP_SYSCALL:

        cause = 8;

        goto set_EPC;

    case EXCP_BREAK:

        cause = 9;

        goto set_EPC;

    case EXCP_RI:

        cause = 10;

        goto set_EPC;

    case EXCP_CpU:

        cause = 11;

        env->CP0_Cause = (env->CP0_Cause & ~0x03000000) | (env->error_code << 28);

        goto set_EPC;

    case EXCP_OVERFLOW:

        cause = 12;

        goto set_EPC;

    case EXCP_TRAP:

        cause = 13;

        goto set_EPC;

    case EXCP_LTLBL:

        cause = 1;

        goto set_EPC;

    case EXCP_TLBS:

        cause = 3;

        if (env->error_code == 1 && !(env->hflags & MIPS_HFLAG_EXL))

            offset = 0x000;

        goto set_EPC;

    set_EPC:

        if (env->hflags & MIPS_HFLAG_BMASK) {

            /* If the exception was raised from a delay slot,

               come back to the jump.  */

            env->CP0_EPC = env->PC - 4;

            env->CP0_Cause |= 0x80000000;

            env->hflags &= ~MIPS_HFLAG_BMASK;

        } else {

            env->CP0_EPC = env->PC;

            env->CP0_Cause &= ~0x80000000;

        }

        if (env->CP0_Status & (1 << CP0St_BEV)) {

            env->PC = SIGN_EXTEND32(0xBFC00200);

        } else {

            env->PC = SIGN_EXTEND32(0x80000000);

        }

        env->hflags |= MIPS_HFLAG_EXL;

        env->CP0_Status |= (1 << CP0St_EXL);

        env->PC += offset;

        env->CP0_Cause = (env->CP0_Cause & ~0x7C) | (cause << 2);

        break;

    default:

        if (logfile) {

            fprintf(logfile, "Invalid MIPS exception %d. Exiting\n",

                    env->exception_index);

        }

        printf("Invalid MIPS exception %d. Exiting\n", env->exception_index);

        exit(1);

    }

    if (logfile && env->exception_index != EXCP_EXT_INTERRUPT) {

        fprintf(logfile, "%s: PC " TLSZ " EPC " TLSZ " cause %d excp %d\n"

                "    S %08x C %08x A " TLSZ " D " TLSZ "\n",

                __func__, env->PC, env->CP0_EPC, cause, env->exception_index,

                env->CP0_Status, env->CP0_Cause, env->CP0_BadVAddr,

                env->CP0_DEPC);

    }

    env->exception_index = EXCP_NONE;

}

#endif /* !defined(CONFIG_USER_ONLY) */