[MIPS] Import MIPS target support

From v0.12.5 tag at git://git.sv.gnu.org/qemu.git
CommitID: 174f225e9d62e8f3002e274e4f718bd2a967fbf4

Change-Id: I35b49a4319cee4b69cf9da4e5af1f43327e21056
Signed-off-by: Chris Dearman <chris@mips.com>

1 files changed, 647 insertions, 0 deletions

diff --git a/target-mips/helper.c b/target-mips/helper.c
new file mode 100644
index 0000000..ec87114
--- /dev/null
+++ b/target-mips/helper.c
@@ -0,0 +1,647 @@
+/*
+ *  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, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include <signal.h>
+
+#include "cpu.h"
+#include "exec-all.h"
+
+enum {
+    TLBRET_DIRTY = -4,
+    TLBRET_INVALID = -3,
+    TLBRET_NOMATCH = -2,
+    TLBRET_BADADDR = -1,
+    TLBRET_MATCH = 0
+};
+
+/* no MMU emulation */
+int no_mmu_map_address (CPUState *env, target_phys_addr_t *physical, int *prot,
+                        target_ulong address, int rw, int access_type)
+{
+    *physical = address;
+    *prot = PAGE_READ | PAGE_WRITE;
+    return TLBRET_MATCH;
+}
+
+/* fixed mapping MMU emulation */
+int fixed_mmu_map_address (CPUState *env, target_phys_addr_t *physical, int *prot,
+                           target_ulong address, int rw, int access_type)
+{
+    if (address <= (int32_t)0x7FFFFFFFUL) {
+        if (!(env->CP0_Status & (1 << CP0St_ERL)))
+            *physical = address + 0x40000000UL;
+        else
+            *physical = address;
+    } else if (address <= (int32_t)0xBFFFFFFFUL)
+        *physical = address & 0x1FFFFFFF;
+    else
+        *physical = address;
+
+    *prot = PAGE_READ | PAGE_WRITE;
+    return TLBRET_MATCH;
+}
+
+/* MIPS32/MIPS64 R4000-style MMU emulation */
+int r4k_map_address (CPUState *env, target_phys_addr_t *physical, int *prot,
+                     target_ulong address, int rw, int access_type)
+{
+    uint8_t ASID = env->CP0_EntryHi & 0xFF;
+    int i;
+
+    for (i = 0; i < env->tlb->tlb_in_use; i++) {
+        r4k_tlb_t *tlb = &env->tlb->mmu.r4k.tlb[i];
+        /* 1k pages are not supported. */
+        target_ulong mask = tlb->PageMask | ~(TARGET_PAGE_MASK << 1);
+        target_ulong tag = address & ~mask;
+        target_ulong VPN = tlb->VPN & ~mask;
+#if defined(TARGET_MIPS64)
+        tag &= env->SEGMask;
+#endif
+
+        /* Check ASID, virtual page number & size */
+        if ((tlb->G == 1 || tlb->ASID == ASID) && VPN == tag) {
+            /* TLB match */
+            int n = !!(address & mask & ~(mask >> 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 & (mask >> 1));
+                *prot = PAGE_READ;
+                if (n ? tlb->D1 : tlb->D0)
+                    *prot |= PAGE_WRITE;
+                return TLBRET_MATCH;
+            }
+            return TLBRET_DIRTY;
+        }
+    }
+    return TLBRET_NOMATCH;
+}
+
+#if !defined(CONFIG_USER_ONLY)
+static int get_physical_address (CPUState *env, target_phys_addr_t *physical,
+                                int *prot, target_ulong address,
+                                int rw, int access_type)
+{
+    /* User mode can only access useg/xuseg */
+    int user_mode = (env->hflags & MIPS_HFLAG_MODE) == MIPS_HFLAG_UM;
+    int supervisor_mode = (env->hflags & MIPS_HFLAG_MODE) == MIPS_HFLAG_SM;
+    int kernel_mode = !user_mode && !supervisor_mode;
+#if defined(TARGET_MIPS64)
+    int UX = (env->CP0_Status & (1 << CP0St_UX)) != 0;
+    int SX = (env->CP0_Status & (1 << CP0St_SX)) != 0;
+    int KX = (env->CP0_Status & (1 << CP0St_KX)) != 0;
+#endif
+    int ret = TLBRET_MATCH;
+
+#if 0
+    qemu_log("user mode %d h %08x\n", user_mode, env->hflags);
+#endif
+
+    if (address <= (int32_t)0x7FFFFFFFUL) {
+        /* useg */
+        if (env->CP0_Status & (1 << CP0St_ERL)) {
+            *physical = address & 0xFFFFFFFF;
+            *prot = PAGE_READ | PAGE_WRITE;
+        } else {
+            ret = env->tlb->map_address(env, physical, prot, address, rw, access_type);
+        }
+#if defined(TARGET_MIPS64)
+    } else if (address < 0x4000000000000000ULL) {
+        /* xuseg */
+        if (UX && address <= (0x3FFFFFFFFFFFFFFFULL & env->SEGMask)) {
+            ret = env->tlb->map_address(env, physical, prot, address, rw, access_type);
+        } else {
+            ret = TLBRET_BADADDR;
+        }
+    } else if (address < 0x8000000000000000ULL) {
+        /* xsseg */
+        if ((supervisor_mode || kernel_mode) &&
+            SX && address <= (0x7FFFFFFFFFFFFFFFULL & env->SEGMask)) {
+            ret = env->tlb->map_address(env, physical, prot, address, rw, access_type);
+        } else {
+            ret = TLBRET_BADADDR;
+        }
+    } else if (address < 0xC000000000000000ULL) {
+        /* xkphys */
+        if (kernel_mode && KX &&
+            (address & 0x07FFFFFFFFFFFFFFULL) <= env->PAMask) {
+            *physical = address & env->PAMask;
+            *prot = PAGE_READ | PAGE_WRITE;
+        } else {
+            ret = TLBRET_BADADDR;
+        }
+    } else if (address < 0xFFFFFFFF80000000ULL) {
+        /* xkseg */
+        if (kernel_mode && KX &&
+            address <= (0xFFFFFFFF7FFFFFFFULL & env->SEGMask)) {
+            ret = env->tlb->map_address(env, physical, prot, address, rw, access_type);
+        } else {
+            ret = TLBRET_BADADDR;
+        }
+#endif
+    } else if (address < (int32_t)0xA0000000UL) {
+        /* kseg0 */
+        if (kernel_mode) {
+            *physical = address - (int32_t)0x80000000UL;
+            *prot = PAGE_READ | PAGE_WRITE;
+        } else {
+            ret = TLBRET_BADADDR;
+        }
+    } else if (address < (int32_t)0xC0000000UL) {
+        /* kseg1 */
+        if (kernel_mode) {
+            *physical = address - (int32_t)0xA0000000UL;
+            *prot = PAGE_READ | PAGE_WRITE;
+        } else {
+            ret = TLBRET_BADADDR;
+        }
+    } else if (address < (int32_t)0xE0000000UL) {
+        /* sseg (kseg2) */
+        if (supervisor_mode || kernel_mode) {
+            ret = env->tlb->map_address(env, physical, prot, address, rw, access_type);
+        } else {
+            ret = TLBRET_BADADDR;
+        }
+    } else {
+        /* kseg3 */
+        /* XXX: debug segment is not emulated */
+        if (kernel_mode) {
+            ret = env->tlb->map_address(env, physical, prot, address, rw, access_type);
+        } else {
+            ret = TLBRET_BADADDR;
+        }
+    }
+#if 0
+    qemu_log(TARGET_FMT_lx " %d %d => " TARGET_FMT_lx " %d (%d)\n",
+            address, rw, access_type, *physical, *prot, ret);
+#endif
+
+    return ret;
+}
+#endif
+
+static void raise_mmu_exception(CPUState *env, target_ulong address,
+                                int rw, int tlb_error)
+{
+    int exception = 0, error_code = 0;
+
+    switch (tlb_error) {
+    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 & ~0x007fffff) |
+                       ((address >> 9) & 0x007ffff0);
+    env->CP0_EntryHi =
+        (env->CP0_EntryHi & 0xFF) | (address & (TARGET_PAGE_MASK << 1));
+#if defined(TARGET_MIPS64)
+    env->CP0_EntryHi &= env->SEGMask;
+    env->CP0_XContext = (env->CP0_XContext & ((~0ULL) << (env->SEGBITS - 7))) |
+                        ((address & 0xC00000000000ULL) >> (55 - env->SEGBITS)) |
+                        ((address & ((1ULL << env->SEGBITS) - 1) & 0xFFFFFFFFFFFFE000ULL) >> 9);
+#endif
+    env->exception_index = exception;
+    env->error_code = error_code;
+}
+
+target_phys_addr_t cpu_get_phys_page_debug(CPUState *env, target_ulong addr)
+{
+#if defined(CONFIG_USER_ONLY)
+    return addr;
+#else
+    target_phys_addr_t phys_addr;
+    int prot;
+
+    if (get_physical_address(env, &phys_addr, &prot, addr, 0, ACCESS_INT) != 0)
+        return -1;
+    return phys_addr;
+#endif
+}
+
+int cpu_mips_handle_mmu_fault (CPUState *env, target_ulong address, int rw,
+                               int mmu_idx, int is_softmmu)
+{
+#if !defined(CONFIG_USER_ONLY)
+    target_phys_addr_t physical;
+    int prot;
+#endif
+    int access_type;
+    int ret = 0;
+
+#if 0
+    log_cpu_state(env, 0);
+#endif
+    qemu_log("%s pc " TARGET_FMT_lx " ad " TARGET_FMT_lx " rw %d mmu_idx %d smmu %d\n",
+              __func__, env->active_tc.PC, address, rw, mmu_idx, is_softmmu);
+
+    rw &= 1;
+
+    /* data access */
+    /* XXX: put correct access by using cpu_restore_state()
+       correctly */
+    access_type = ACCESS_INT;
+#if defined(CONFIG_USER_ONLY)
+    ret = TLBRET_NOMATCH;
+#else
+    ret = get_physical_address(env, &physical, &prot,
+                               address, rw, access_type);
+    qemu_log("%s address=" TARGET_FMT_lx " ret %d physical " TARGET_FMT_plx " 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,
+                          mmu_idx, is_softmmu);
+    } else if (ret < 0)
+#endif
+    {
+        raise_mmu_exception(env, address, rw, ret);
+        ret = 1;
+    }
+
+    return ret;
+}
+
+#if !defined(CONFIG_USER_ONLY)
+target_phys_addr_t cpu_mips_translate_address(CPUState *env, target_ulong address, int rw)
+{
+    target_phys_addr_t physical;
+    int prot;
+    int access_type;
+    int ret = 0;
+
+    rw &= 1;
+
+    /* data access */
+    access_type = ACCESS_INT;
+    ret = get_physical_address(env, &physical, &prot,
+                               address, rw, access_type);
+    if (ret != TLBRET_MATCH) {
+        raise_mmu_exception(env, address, rw, ret);
+        return -1LL;
+    } else {
+        return physical;
+    }
+}
+#endif
+
+static const char * const excp_names[EXCP_LAST + 1] = {
+    [EXCP_RESET] = "reset",
+    [EXCP_SRESET] = "soft reset",
+    [EXCP_DSS] = "debug single step",
+    [EXCP_DINT] = "debug interrupt",
+    [EXCP_NMI] = "non-maskable interrupt",
+    [EXCP_MCHECK] = "machine check",
+    [EXCP_EXT_INTERRUPT] = "interrupt",
+    [EXCP_DFWATCH] = "deferred watchpoint",
+    [EXCP_DIB] = "debug instruction breakpoint",
+    [EXCP_IWATCH] = "instruction fetch watchpoint",
+    [EXCP_AdEL] = "address error load",
+    [EXCP_AdES] = "address error store",
+    [EXCP_TLBF] = "TLB refill",
+    [EXCP_IBE] = "instruction bus error",
+    [EXCP_DBp] = "debug breakpoint",
+    [EXCP_SYSCALL] = "syscall",
+    [EXCP_BREAK] = "break",
+    [EXCP_CpU] = "coprocessor unusable",
+    [EXCP_RI] = "reserved instruction",
+    [EXCP_OVERFLOW] = "arithmetic overflow",
+    [EXCP_TRAP] = "trap",
+    [EXCP_FPE] = "floating point",
+    [EXCP_DDBS] = "debug data break store",
+    [EXCP_DWATCH] = "data watchpoint",
+    [EXCP_LTLBL] = "TLB modify",
+    [EXCP_TLBL] = "TLB load",
+    [EXCP_TLBS] = "TLB store",
+    [EXCP_DBE] = "data bus error",
+    [EXCP_DDBL] = "debug data break load",
+    [EXCP_THREAD] = "thread",
+    [EXCP_MDMX] = "MDMX",
+    [EXCP_C2E] = "precise coprocessor 2",
+    [EXCP_CACHE] = "cache error",
+};
+
+void do_interrupt (CPUState *env)
+{
+#if !defined(CONFIG_USER_ONLY)
+    target_ulong offset;
+    int cause = -1;
+    const char *name;
+
+    if (qemu_log_enabled() && env->exception_index != EXCP_EXT_INTERRUPT) {
+        if (env->exception_index < 0 || env->exception_index > EXCP_LAST)
+            name = "unknown";
+        else
+            name = excp_names[env->exception_index];
+
+        qemu_log("%s enter: PC " TARGET_FMT_lx " EPC " TARGET_FMT_lx " %s exception\n",
+                 __func__, env->active_tc.PC, env->CP0_EPC, name);
+    }
+    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->active_tc.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;
+    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->active_tc.PC - 4;
+            env->hflags &= ~MIPS_HFLAG_BMASK;
+        } else {
+            env->CP0_DEPC = env->active_tc.PC;
+        }
+ enter_debug_mode:
+        env->hflags |= MIPS_HFLAG_DM | MIPS_HFLAG_64 | MIPS_HFLAG_CP0;
+        env->hflags &= ~(MIPS_HFLAG_KSU);
+        /* EJTAG probe trap enable is not implemented... */
+        if (!(env->CP0_Status & (1 << CP0St_EXL)))
+            env->CP0_Cause &= ~(1 << CP0Ca_BD);
+        env->active_tc.PC = (int32_t)0xBFC00480;
+        break;
+    case EXCP_RESET:
+        cpu_reset(env);
+        break;
+    case EXCP_SRESET:
+        env->CP0_Status |= (1 << CP0St_SR);
+        memset(env->CP0_WatchLo, 0, sizeof(*env->CP0_WatchLo));
+        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->active_tc.PC - 4;
+            env->hflags &= ~MIPS_HFLAG_BMASK;
+        } else {
+            env->CP0_ErrorEPC = env->active_tc.PC;
+        }
+        env->CP0_Status |= (1 << CP0St_ERL) | (1 << CP0St_BEV);
+        env->hflags |= MIPS_HFLAG_64 | MIPS_HFLAG_CP0;
+        env->hflags &= ~(MIPS_HFLAG_KSU);
+        if (!(env->CP0_Status & (1 << CP0St_EXL)))
+            env->CP0_Cause &= ~(1 << CP0Ca_BD);
+        env->active_tc.PC = (int32_t)0xBFC00000;
+        break;
+    case EXCP_EXT_INTERRUPT:
+        cause = 0;
+        if (env->CP0_Cause & (1 << CP0Ca_IV))
+            offset = 0x200;
+        goto set_EPC;
+    case EXCP_LTLBL:
+        cause = 1;
+        goto set_EPC;
+    case EXCP_TLBL:
+        cause = 2;
+        if (env->error_code == 1 && !(env->CP0_Status & (1 << CP0St_EXL))) {
+#if defined(TARGET_MIPS64)
+            int R = env->CP0_BadVAddr >> 62;
+            int UX = (env->CP0_Status & (1 << CP0St_UX)) != 0;
+            int SX = (env->CP0_Status & (1 << CP0St_SX)) != 0;
+            int KX = (env->CP0_Status & (1 << CP0St_KX)) != 0;
+
+            if ((R == 0 && UX) || (R == 1 && SX) || (R == 3 && KX))
+                offset = 0x080;
+            else
+#endif
+                offset = 0x000;
+        }
+        goto set_EPC;
+    case EXCP_TLBS:
+        cause = 3;
+        if (env->error_code == 1 && !(env->CP0_Status & (1 << CP0St_EXL))) {
+#if defined(TARGET_MIPS64)
+            int R = env->CP0_BadVAddr >> 62;
+            int UX = (env->CP0_Status & (1 << CP0St_UX)) != 0;
+            int SX = (env->CP0_Status & (1 << CP0St_SX)) != 0;
+            int KX = (env->CP0_Status & (1 << CP0St_KX)) != 0;
+
+            if ((R == 0 && UX) || (R == 1 && SX) || (R == 3 && KX))
+                offset = 0x080;
+            else
+#endif
+                offset = 0x000;
+        }
+        goto set_EPC;
+    case EXCP_AdEL:
+        cause = 4;
+        goto set_EPC;
+    case EXCP_AdES:
+        cause = 5;
+        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 & ~(0x3 << CP0Ca_CE)) |
+                         (env->error_code << CP0Ca_CE);
+        goto set_EPC;
+    case EXCP_OVERFLOW:
+        cause = 12;
+        goto set_EPC;
+    case EXCP_TRAP:
+        cause = 13;
+        goto set_EPC;
+    case EXCP_FPE:
+        cause = 15;
+        goto set_EPC;
+    case EXCP_C2E:
+        cause = 18;
+        goto set_EPC;
+    case EXCP_MDMX:
+        cause = 22;
+        goto set_EPC;
+    case EXCP_DWATCH:
+        cause = 23;
+        /* XXX: TODO: manage defered watch exceptions */
+        goto set_EPC;
+    case EXCP_MCHECK:
+        cause = 24;
+        goto set_EPC;
+    case EXCP_THREAD:
+        cause = 25;
+        goto set_EPC;
+    case EXCP_CACHE:
+        cause = 30;
+        if (env->CP0_Status & (1 << CP0St_BEV)) {
+            offset = 0x100;
+        } else {
+            offset = 0x20000100;
+        }
+ set_EPC:
+        if (!(env->CP0_Status & (1 << CP0St_EXL))) {
+            if (env->hflags & MIPS_HFLAG_BMASK) {
+                /* If the exception was raised from a delay slot,
+                   come back to the jump.  */
+                env->CP0_EPC = env->active_tc.PC - 4;
+                env->CP0_Cause |= (1 << CP0Ca_BD);
+            } else {
+                env->CP0_EPC = env->active_tc.PC;
+                env->CP0_Cause &= ~(1 << CP0Ca_BD);
+            }
+            env->CP0_Status |= (1 << CP0St_EXL);
+            env->hflags |= MIPS_HFLAG_64 | MIPS_HFLAG_CP0;
+            env->hflags &= ~(MIPS_HFLAG_KSU);
+        }
+        env->hflags &= ~MIPS_HFLAG_BMASK;
+        if (env->CP0_Status & (1 << CP0St_BEV)) {
+            env->active_tc.PC = (int32_t)0xBFC00200;
+        } else {
+            env->active_tc.PC = (int32_t)(env->CP0_EBase & ~0x3ff);
+        }
+        env->active_tc.PC += offset;
+        env->CP0_Cause = (env->CP0_Cause & ~(0x1f << CP0Ca_EC)) | (cause << CP0Ca_EC);
+        break;
+    default:
+        qemu_log("Invalid MIPS exception %d. Exiting\n", env->exception_index);
+        printf("Invalid MIPS exception %d. Exiting\n", env->exception_index);
+        exit(1);
+    }
+    if (qemu_log_enabled() && env->exception_index != EXCP_EXT_INTERRUPT) {
+        qemu_log("%s: PC " TARGET_FMT_lx " EPC " TARGET_FMT_lx " cause %d\n"
+                "    S %08x C %08x A " TARGET_FMT_lx " D " TARGET_FMT_lx "\n",
+                __func__, env->active_tc.PC, env->CP0_EPC, cause,
+                env->CP0_Status, env->CP0_Cause, env->CP0_BadVAddr,
+                env->CP0_DEPC);
+    }
+#endif
+    env->exception_index = EXCP_NONE;
+}
+
+void r4k_invalidate_tlb (CPUState *env, int idx, int use_extra)
+{
+    r4k_tlb_t *tlb;
+    target_ulong addr;
+    target_ulong end;
+    uint8_t ASID = env->CP0_EntryHi & 0xFF;
+    target_ulong mask;
+
+    tlb = &env->tlb->mmu.r4k.tlb[idx];
+    /* The qemu TLB is flushed when the ASID changes, so no need to
+       flush these entries again.  */
+    if (tlb->G == 0 && tlb->ASID != ASID) {
+        return;
+    }
+
+    if (use_extra && env->tlb->tlb_in_use < MIPS_TLB_MAX) {
+        /* For tlbwr, we can shadow the discarded entry into
+           a new (fake) TLB entry, as long as the guest can not
+           tell that it's there.  */
+        env->tlb->mmu.r4k.tlb[env->tlb->tlb_in_use] = *tlb;
+        env->tlb->tlb_in_use++;
+        return;
+    }
+
+    /* 1k pages are not supported. */
+    mask = tlb->PageMask | ~(TARGET_PAGE_MASK << 1);
+    if (tlb->V0) {
+        addr = tlb->VPN & ~mask;
+#if defined(TARGET_MIPS64)
+        if (addr >= (0xFFFFFFFF80000000ULL & env->SEGMask)) {
+            addr |= 0x3FFFFF0000000000ULL;
+        }
+#endif
+        end = addr | (mask >> 1);
+        while (addr < end) {
+            tlb_flush_page (env, addr);
+            addr += TARGET_PAGE_SIZE;
+        }
+    }
+    if (tlb->V1) {
+        addr = (tlb->VPN & ~mask) | ((mask >> 1) + 1);
+#if defined(TARGET_MIPS64)
+        if (addr >= (0xFFFFFFFF80000000ULL & env->SEGMask)) {
+            addr |= 0x3FFFFF0000000000ULL;
+        }
+#endif
+        end = addr | mask;
+        while (addr - 1 < end) {
+            tlb_flush_page (env, addr);
+            addr += TARGET_PAGE_SIZE;
+        }
+    }
+}