target-microblaze/mmu.c

   1 /*
   2  *  Microblaze MMU emulation for qemu.
   3  *
   4  *  Copyright (c) 2009 Edgar E. Iglesias
   5  *  Copyright (c) 2009-2012 PetaLogix Qld Pty Ltd.
   6  *
   7  * This library is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2 of the License, or (at your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "cpu.h"
  22
  23 #define D(x)
  24
  25 static unsigned int tlb_decode_size(unsigned int f)
  26 {
  27     static const unsigned int sizes[] = {
  28         1 * 1024, 4 * 1024, 16 * 1024, 64 * 1024, 256 * 1024,
  29         1 * 1024 * 1024, 4 * 1024 * 1024, 16 * 1024 * 1024
  30     };
  31     assert(f < ARRAY_SIZE(sizes));
  32     return sizes[f];
  33 }
  34
  35 static void mmu_flush_idx(CPUMBState *env, unsigned int idx)
  36 {
  37     struct microblaze_mmu *mmu = &env->mmu;
  38     unsigned int tlb_size;
  39     uint32_t tlb_tag, end, t;
  40
  41     t = mmu->rams[RAM_TAG][idx];
  42     if (!(t & TLB_VALID))
  43         return;
  44
  45     tlb_tag = t & TLB_EPN_MASK;
  46     tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
  47     end = tlb_tag + tlb_size;
  48
  49     while (tlb_tag < end) {
  50         tlb_flush_page(env, tlb_tag);
  51         tlb_tag += TARGET_PAGE_SIZE;
  52     }
  53 }
  54
  55 static void mmu_change_pid(CPUMBState *env, unsigned int newpid)
  56 {
  57     struct microblaze_mmu *mmu = &env->mmu;
  58     unsigned int i;
  59     uint32_t t;
  60
  61     if (newpid & ~0xff)
  62         qemu_log("Illegal rpid=%x\n", newpid);
  63
  64     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
  65         /* Lookup and decode.  */
  66         t = mmu->rams[RAM_TAG][i];
  67         if (t & TLB_VALID) {
  68             if (mmu->tids[i] && ((mmu->regs[MMU_R_PID] & 0xff) == mmu->tids[i]))
  69                 mmu_flush_idx(env, i);
  70         }
  71     }
  72 }
  73
  74 /* rw - 0 = read, 1 = write, 2 = fetch.  */
  75 unsigned int mmu_translate(struct microblaze_mmu *mmu,
  76                            struct microblaze_mmu_lookup *lu,
  77                            target_ulong vaddr, int rw, int mmu_idx)
  78 {
  79     unsigned int i, hit = 0;
  80     unsigned int tlb_ex = 0, tlb_wr = 0, tlb_zsel;
  81     unsigned int tlb_size;
  82     uint32_t tlb_tag, tlb_rpn, mask, t0;
  83
  84     lu->err = ERR_MISS;
  85     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
  86         uint32_t t, d;
  87
  88         /* Lookup and decode.  */
  89         t = mmu->rams[RAM_TAG][i];
  90         D(qemu_log("TLB %d valid=%d\n", i, t & TLB_VALID));
  91         if (t & TLB_VALID) {
  92             tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
  93             if (tlb_size < TARGET_PAGE_SIZE) {
  94                 qemu_log("%d pages not supported\n", tlb_size);
  95                 abort();
  96             }
  97
  98             mask = ~(tlb_size - 1);
  99             tlb_tag = t & TLB_EPN_MASK;
 100             if ((vaddr & mask) != (tlb_tag & mask)) {
 101                 D(qemu_log("TLB %d vaddr=%x != tag=%x\n",
 102                            i, vaddr & mask, tlb_tag & mask));
 103                 continue;
 104             }
 105             if (mmu->tids[i]
 106                 && ((mmu->regs[MMU_R_PID] & 0xff) != mmu->tids[i])) {
 107                 D(qemu_log("TLB %d pid=%x != tid=%x\n",
 108                            i, mmu->regs[MMU_R_PID], mmu->tids[i]));
 109                 continue;
 110             }
 111
 112             /* Bring in the data part.  */
 113             d = mmu->rams[RAM_DATA][i];
 114             tlb_ex = d & TLB_EX;
 115             tlb_wr = d & TLB_WR;
 116
 117             /* Now let's see if there is a zone that overrides the protbits.  */
 118             tlb_zsel = (d >> 4) & 0xf;
 119             t0 = mmu->regs[MMU_R_ZPR] >> (30 - (tlb_zsel * 2));
 120             t0 &= 0x3;
 121
 122             if (tlb_zsel > mmu->c_mmu_zones) {
 123                 qemu_log("tlb zone select out of range! %d\n", tlb_zsel);
 124                 t0 = 1; /* Ignore.  */
 125             }
 126
 127             if (mmu->c_mmu == 1) {
 128                 t0 = 1; /* Zones are disabled.  */
 129             }
 130
 131             switch (t0) {
 132                 case 0:
 133                     if (mmu_idx == MMU_USER_IDX)
 134                         continue;
 135                     break;
 136                 case 2:
 137                     if (mmu_idx != MMU_USER_IDX) {
 138                         tlb_ex = 1;
 139                         tlb_wr = 1;
 140                     }
 141                     break;
 142                 case 3:
 143                     tlb_ex = 1;
 144                     tlb_wr = 1;
 145                     break;
 146                 default: break;
 147             }
 148
 149             lu->err = ERR_PROT;
 150             lu->prot = PAGE_READ;
 151             if (tlb_wr)
 152                 lu->prot |= PAGE_WRITE;
 153             else if (rw == 1)
 154                 goto done;
 155             if (tlb_ex)
 156                 lu->prot |=PAGE_EXEC;
 157             else if (rw == 2) {
 158                 goto done;
 159             }
 160
 161             tlb_rpn = d & TLB_RPN_MASK;
 162
 163             lu->vaddr = tlb_tag;
 164             lu->paddr = tlb_rpn;
 165             lu->size = tlb_size;
 166             lu->err = ERR_HIT;
 167             lu->idx = i;
 168             hit = 1;
 169             goto done;
 170         }
 171     }
 172 done:
 173     D(qemu_log("MMU vaddr=%x rw=%d tlb_wr=%d tlb_ex=%d hit=%d\n",
 174               vaddr, rw, tlb_wr, tlb_ex, hit));
 175     return hit;
 176 }
 177
 178 /* Writes/reads to the MMU's special regs end up here.  */
 179 uint32_t mmu_read(CPUMBState *env, uint32_t rn)
 180 {
 181     unsigned int i;
 182     uint32_t r;
 183
 184     if (env->mmu.c_mmu < 2 || !env->mmu.c_mmu_tlb_access) {
 185         qemu_log("MMU access on MMU-less system\n");
 186         return 0;
 187     }
 188
 189     switch (rn) {
 190         /* Reads to HI/LO trig reads from the mmu rams.  */
 191         case MMU_R_TLBLO:
 192         case MMU_R_TLBHI:
 193             if (!(env->mmu.c_mmu_tlb_access & 1)) {
 194                 qemu_log("Invalid access to MMU reg %d\n", rn);
 195                 return 0;
 196             }
 197
 198             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
 199             r = env->mmu.rams[rn & 1][i];
 200             if (rn == MMU_R_TLBHI)
 201                 env->mmu.regs[MMU_R_PID] = env->mmu.tids[i];
 202             break;
 203         case MMU_R_PID:
 204         case MMU_R_ZPR:
 205             if (!(env->mmu.c_mmu_tlb_access & 1)) {
 206                 qemu_log("Invalid access to MMU reg %d\n", rn);
 207                 return 0;
 208             }
 209             r = env->mmu.regs[rn];
 210             break;
 211         default:
 212             r = env->mmu.regs[rn];
 213             break;
 214     }
 215     D(qemu_log("%s rn=%d=%x\n", __func__, rn, r));
 216     return r;
 217 }
 218
 219 void mmu_write(CPUMBState *env, uint32_t rn, uint32_t v)
 220 {
 221     unsigned int i;
 222     D(qemu_log("%s rn=%d=%x old=%x\n", __func__, rn, v, env->mmu.regs[rn]));
 223
 224     if (env->mmu.c_mmu < 2 || !env->mmu.c_mmu_tlb_access) {
 225         qemu_log("MMU access on MMU-less system\n");
 226         return;
 227     }
 228
 229     switch (rn) {
 230         /* Writes to HI/LO trig writes to the mmu rams.  */
 231         case MMU_R_TLBLO:
 232         case MMU_R_TLBHI:
 233             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
 234             if (rn == MMU_R_TLBHI) {
 235                 if (i < 3 && !(v & TLB_VALID) && qemu_loglevel_mask(~0))
 236                     qemu_log("invalidating index %x at pc=%x\n",
 237                              i, env->sregs[SR_PC]);
 238                 env->mmu.tids[i] = env->mmu.regs[MMU_R_PID] & 0xff;
 239                 mmu_flush_idx(env, i);
 240             }
 241             env->mmu.rams[rn & 1][i] = v;
 242
 243             D(qemu_log("%s ram[%d][%d]=%x\n", __func__, rn & 1, i, v));
 244             break;
 245         case MMU_R_ZPR:
 246             if (env->mmu.c_mmu_tlb_access <= 1) {
 247                 qemu_log("Invalid access to MMU reg %d\n", rn);
 248                 return;
 249             }
 250
 251             /* Changes to the zone protection reg flush the QEMU TLB.
 252                Fortunately, these are very uncommon.  */
 253             if (v != env->mmu.regs[rn]) {
 254                 tlb_flush(env, 1);
 255             }
 256             env->mmu.regs[rn] = v;
 257             break;
 258         case MMU_R_PID:
 259             if (env->mmu.c_mmu_tlb_access <= 1) {
 260                 qemu_log("Invalid access to MMU reg %d\n", rn);
 261                 return;
 262             }
 263
 264             if (v != env->mmu.regs[rn]) {
 265                 mmu_change_pid(env, v);
 266                 env->mmu.regs[rn] = v;
 267             }
 268             break;
 269         case MMU_R_TLBSX:
 270         {
 271             struct microblaze_mmu_lookup lu;
 272             int hit;
 273
 274             if (env->mmu.c_mmu_tlb_access <= 1) {
 275                 qemu_log("Invalid access to MMU reg %d\n", rn);
 276                 return;
 277             }
 278
 279             hit = mmu_translate(&env->mmu, &lu,
 280                                 v & TLB_EPN_MASK, 0, cpu_mmu_index(env));
 281             if (hit) {
 282                 env->mmu.regs[MMU_R_TLBX] = lu.idx;
 283             } else
 284                 env->mmu.regs[MMU_R_TLBX] |= 0x80000000;
 285             break;
 286         }
 287         default:
 288             env->mmu.regs[rn] = v;
 289             break;
 290    }
 291 }
 292
 293 void mmu_init(struct microblaze_mmu *mmu)
 294 {
 295     int i;
 296     for (i = 0; i < ARRAY_SIZE(mmu->regs); i++) {
 297         mmu->regs[i] = 0;
 298     }
 299 }