target-microblaze/mmu.c

   1 /*
   2  *  Microblaze MMU emulation for qemu.
   3  *
   4  *  Copyright (c) 2009 Edgar E. Iglesias
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <assert.h>
  22
  23 #include "config.h"
  24 #include "cpu.h"
  25 #include "exec-all.h"
  26
  27 #define D(x)
  28
  29 static unsigned int tlb_decode_size(unsigned int f)
  30 {
  31     static const unsigned int sizes[] = {
  32         1 * 1024, 4 * 1024, 16 * 1024, 64 * 1024, 256 * 1024,
  33         1 * 1024 * 1024, 4 * 1024 * 1024, 16 * 1024 * 1024
  34     };
  35     assert(f < ARRAY_SIZE(sizes));
  36     return sizes[f];
  37 }
  38
  39 static void mmu_flush_idx(CPUState *env, unsigned int idx)
  40 {
  41     struct microblaze_mmu *mmu = &env->mmu;
  42     unsigned int tlb_size;
  43     uint32_t tlb_tag, end, t;
  44
  45     t = mmu->rams[RAM_TAG][idx];
  46     if (!(t & TLB_VALID))
  47         return;
  48
  49     tlb_tag = t & TLB_EPN_MASK;
  50     tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
  51     end = tlb_tag + tlb_size;
  52
  53     while (tlb_tag < end) {
  54         tlb_flush_page(env, tlb_tag);
  55         tlb_tag += TARGET_PAGE_SIZE;
  56     }
  57 }
  58
  59 static void mmu_change_pid(CPUState *env, unsigned int newpid)
  60 {
  61     struct microblaze_mmu *mmu = &env->mmu;
  62     unsigned int i;
  63     unsigned int tlb_size;
  64     uint32_t tlb_tag, mask, t;
  65
  66     if (newpid & ~0xff)
  67         qemu_log("Illegal rpid=%x\n", newpid);
  68
  69     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
  70         /* Lookup and decode.  */
  71         t = mmu->rams[RAM_TAG][i];
  72         if (t & TLB_VALID) {
  73             tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
  74             mask = ~(tlb_size - 1);
  75
  76             tlb_tag = t & TLB_EPN_MASK;
  77             if (mmu->tids[i] && ((mmu->regs[MMU_R_PID] & 0xff) == mmu->tids[i]))
  78                 mmu_flush_idx(env, i);
  79         }
  80     }
  81 }
  82
  83 /* rw - 0 = read, 1 = write, 2 = fetch.  */
  84 unsigned int mmu_translate(struct microblaze_mmu *mmu,
  85                            struct microblaze_mmu_lookup *lu,
  86                            target_ulong vaddr, int rw, int mmu_idx)
  87 {
  88     unsigned int i, hit = 0;
  89     unsigned int tlb_ex = 0, tlb_wr = 0, tlb_zsel;
  90     unsigned int tlb_size;
  91     uint32_t tlb_tag, tlb_rpn, mask, t0;
  92
  93     lu->err = ERR_MISS;
  94     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
  95         uint32_t t, d;
  96
  97         /* Lookup and decode.  */
  98         t = mmu->rams[RAM_TAG][i];
  99         D(qemu_log("TLB %d valid=%d\n", i, t & TLB_VALID));
 100         if (t & TLB_VALID) {
 101             tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
 102             if (tlb_size < TARGET_PAGE_SIZE) {
 103                 qemu_log("%d pages not supported\n", tlb_size);
 104                 abort();
 105             }
 106
 107             mask = ~(tlb_size - 1);
 108             tlb_tag = t & TLB_EPN_MASK;
 109             if ((vaddr & mask) != (tlb_tag & mask)) {
 110                 D(qemu_log("TLB %d vaddr=%x != tag=%x\n",
 111                            i, vaddr & mask, tlb_tag & mask));
 112                 continue;
 113             }
 114             if (mmu->tids[i]
 115                 && ((mmu->regs[MMU_R_PID] & 0xff) != mmu->tids[i])) {
 116                 D(qemu_log("TLB %d pid=%x != tid=%x\n",
 117                            i, mmu->regs[MMU_R_PID], mmu->tids[i]));
 118                 continue;
 119             }
 120
 121             /* Bring in the data part.  */
 122             d = mmu->rams[RAM_DATA][i];
 123             tlb_ex = d & TLB_EX;
 124             tlb_wr = d & TLB_WR;
 125
 126             /* Now lets see if there is a zone that overrides the protbits.  */
 127             tlb_zsel = (d >> 4) & 0xf;
 128             t0 = mmu->regs[MMU_R_ZPR] >> (30 - (tlb_zsel * 2));
 129             t0 &= 0x3;
 130             switch (t0) {
 131                 case 0:
 132                     if (mmu_idx == MMU_USER_IDX)
 133                         continue;
 134                     break;
 135                 case 2:
 136                     if (mmu_idx != MMU_USER_IDX) {
 137                         tlb_ex = 1;
 138                         tlb_wr = 1;
 139                     }
 140                     break;
 141                 case 3:
 142                     tlb_ex = 1;
 143                     tlb_wr = 1;
 144                     break;
 145             }
 146
 147
 148             lu->err = ERR_PROT;
 149             lu->prot = PAGE_READ;
 150             if (tlb_wr)
 151                 lu->prot |= PAGE_WRITE;
 152             else if (rw == 1)
 153                 goto done;
 154             if (tlb_ex)
 155                 lu->prot |=PAGE_EXEC;
 156             else if (rw == 2) {
 157                 goto done;
 158             }
 159
 160             tlb_rpn = d & TLB_RPN_MASK;
 161
 162             lu->vaddr = tlb_tag;
 163             lu->paddr = tlb_rpn;
 164             lu->size = tlb_size;
 165             lu->err = ERR_HIT;
 166             lu->idx = i;
 167             hit = 1;
 168             goto done;
 169         }
 170     }
 171 done:
 172     D(qemu_log("MMU vaddr=%x rw=%d tlb_wr=%d tlb_ex=%d hit=%d\n",
 173               vaddr, rw, tlb_wr, tlb_ex, hit));
 174     return hit;
 175 }
 176
 177 /* Writes/reads to the MMU's special regs end up here.  */
 178 uint32_t mmu_read(CPUState *env, uint32_t rn)
 179 {
 180     unsigned int i;
 181     uint32_t r;
 182
 183     switch (rn) {
 184         /* Reads to HI/LO trig reads from the mmu rams.  */
 185         case MMU_R_TLBLO:
 186         case MMU_R_TLBHI:
 187             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
 188             r = env->mmu.rams[rn & 1][i];
 189             if (rn == MMU_R_TLBHI)
 190                 env->mmu.regs[MMU_R_PID] = env->mmu.tids[i];
 191             break;
 192         default:
 193             r = env->mmu.regs[rn];
 194             break;
 195     }
 196     D(qemu_log("%s rn=%d=%x\n", __func__, rn, r));
 197     return r;
 198 }
 199
 200 void mmu_write(CPUState *env, uint32_t rn, uint32_t v)
 201 {
 202     unsigned int i;
 203     D(qemu_log("%s rn=%d=%x old=%x\n", __func__, rn, v, env->mmu.regs[rn]));
 204
 205     switch (rn) {
 206         /* Writes to HI/LO trig writes to the mmu rams.  */
 207         case MMU_R_TLBLO:
 208         case MMU_R_TLBHI:
 209             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
 210             if (rn == MMU_R_TLBHI) {
 211                 if (i < 3 && !(v & TLB_VALID) && qemu_loglevel_mask(~0))
 212                     qemu_log("invalidating index %x at pc=%x\n",
 213                              i, env->sregs[SR_PC]);
 214                 env->mmu.tids[i] = env->mmu.regs[MMU_R_PID] & 0xff;
 215                 mmu_flush_idx(env, i);
 216             }
 217             env->mmu.rams[rn & 1][i] = v;
 218
 219             D(qemu_log("%s ram[%d][%d]=%x\n", __func__, rn & 1, i, v));
 220             break;
 221         case MMU_R_ZPR:
 222             /* Changes to the zone protection reg flush the QEMU TLB.
 223                Fortunately, these are very uncommon.  */
 224             if (v != env->mmu.regs[rn]) {
 225                 tlb_flush(env, 1);
 226             }
 227             env->mmu.regs[rn] = v;
 228             break;
 229         case MMU_R_PID:
 230             if (v != env->mmu.regs[rn]) {
 231                 mmu_change_pid(env, v);
 232                 env->mmu.regs[rn] = v;
 233             }
 234             break;
 235         case MMU_R_TLBSX:
 236         {
 237             struct microblaze_mmu_lookup lu;
 238             int hit;
 239             hit = mmu_translate(&env->mmu, &lu,
 240                                 v & TLB_EPN_MASK, 0, cpu_mmu_index(env));
 241             if (hit) {
 242                 env->mmu.regs[MMU_R_TLBX] = lu.idx;
 243             } else
 244                 env->mmu.regs[MMU_R_TLBX] |= 0x80000000;
 245             break;
 246         }
 247         default:
 248             env->mmu.regs[rn] = v;
 249             break;
 250    }
 251 }
 252
 253 void mmu_init(struct microblaze_mmu *mmu)
 254 {
 255     memset(mmu, 0, sizeof *mmu);
 256 }