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 2.1 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 "qemu/osdep.h"
  22 #include "cpu.h"
  23 #include "exec/exec-all.h"
  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     CPUState *cs = env_cpu(env);
  38     MicroBlazeMMU *mmu = &env->mmu;
  39     unsigned int tlb_size;
  40     uint32_t tlb_tag, end, t;
  41
  42     t = mmu->rams[RAM_TAG][idx];
  43     if (!(t & TLB_VALID))
  44         return;
  45
  46     tlb_tag = t & TLB_EPN_MASK;
  47     tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
  48     end = tlb_tag + tlb_size;
  49
  50     while (tlb_tag < end) {
  51         tlb_flush_page(cs, tlb_tag);
  52         tlb_tag += TARGET_PAGE_SIZE;
  53     }
  54 }
  55
  56 static void mmu_change_pid(CPUMBState *env, unsigned int newpid)
  57 {
  58     MicroBlazeMMU *mmu = &env->mmu;
  59     unsigned int i;
  60     uint32_t t;
  61
  62     if (newpid & ~0xff)
  63         qemu_log_mask(LOG_GUEST_ERROR, "Illegal rpid=%x\n", newpid);
  64
  65     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
  66         /* Lookup and decode.  */
  67         t = mmu->rams[RAM_TAG][i];
  68         if (t & TLB_VALID) {
  69             if (mmu->tids[i] && ((mmu->regs[MMU_R_PID] & 0xff) == mmu->tids[i]))
  70                 mmu_flush_idx(env, i);
  71         }
  72     }
  73 }
  74
  75 /* rw - 0 = read, 1 = write, 2 = fetch.  */
  76 unsigned int mmu_translate(MicroBlazeCPU *cpu, MicroBlazeMMULookup *lu,
  77                            target_ulong vaddr, int rw, int mmu_idx)
  78 {
  79     MicroBlazeMMU *mmu = &cpu->env.mmu;
  80     unsigned int i, hit = 0;
  81     unsigned int tlb_ex = 0, tlb_wr = 0, tlb_zsel;
  82     uint64_t tlb_tag, tlb_rpn, mask;
  83     uint32_t tlb_size, t0;
  84
  85     lu->err = ERR_MISS;
  86     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
  87         uint64_t t, d;
  88
  89         /* Lookup and decode.  */
  90         t = mmu->rams[RAM_TAG][i];
  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_mask(LOG_UNIMP, "%d pages not supported\n", tlb_size);
  95                 abort();
  96             }
  97
  98             mask = ~((uint64_t)tlb_size - 1);
  99             tlb_tag = t & TLB_EPN_MASK;
 100             if ((vaddr & mask) != (tlb_tag & mask)) {
 101                 continue;
 102             }
 103             if (mmu->tids[i]
 104                 && ((mmu->regs[MMU_R_PID] & 0xff) != mmu->tids[i])) {
 105                 continue;
 106             }
 107
 108             /* Bring in the data part.  */
 109             d = mmu->rams[RAM_DATA][i];
 110             tlb_ex = d & TLB_EX;
 111             tlb_wr = d & TLB_WR;
 112
 113             /* Now let's see if there is a zone that overrides the protbits.  */
 114             tlb_zsel = (d >> 4) & 0xf;
 115             t0 = mmu->regs[MMU_R_ZPR] >> (30 - (tlb_zsel * 2));
 116             t0 &= 0x3;
 117
 118             if (tlb_zsel > cpu->cfg.mmu_zones) {
 119                 qemu_log_mask(LOG_GUEST_ERROR,
 120                               "tlb zone select out of range! %d\n", tlb_zsel);
 121                 t0 = 1; /* Ignore.  */
 122             }
 123
 124             if (cpu->cfg.mmu == 1) {
 125                 t0 = 1; /* Zones are disabled.  */
 126             }
 127
 128             switch (t0) {
 129                 case 0:
 130                     if (mmu_idx == MMU_USER_IDX)
 131                         continue;
 132                     break;
 133                 case 2:
 134                     if (mmu_idx != MMU_USER_IDX) {
 135                         tlb_ex = 1;
 136                         tlb_wr = 1;
 137                     }
 138                     break;
 139                 case 3:
 140                     tlb_ex = 1;
 141                     tlb_wr = 1;
 142                     break;
 143                 default: break;
 144             }
 145
 146             lu->err = ERR_PROT;
 147             lu->prot = PAGE_READ;
 148             if (tlb_wr)
 149                 lu->prot |= PAGE_WRITE;
 150             else if (rw == 1)
 151                 goto done;
 152             if (tlb_ex)
 153                 lu->prot |=PAGE_EXEC;
 154             else if (rw == 2) {
 155                 goto done;
 156             }
 157
 158             tlb_rpn = d & TLB_RPN_MASK;
 159
 160             lu->vaddr = tlb_tag;
 161             lu->paddr = tlb_rpn & cpu->cfg.addr_mask;
 162             lu->size = tlb_size;
 163             lu->err = ERR_HIT;
 164             lu->idx = i;
 165             hit = 1;
 166             goto done;
 167         }
 168     }
 169 done:
 170     qemu_log_mask(CPU_LOG_MMU,
 171                   "MMU vaddr=%" PRIx64 " rw=%d tlb_wr=%d tlb_ex=%d hit=%d\n",
 172                   vaddr, rw, tlb_wr, tlb_ex, hit);
 173     return hit;
 174 }
 175
 176 /* Writes/reads to the MMU's special regs end up here.  */
 177 uint32_t mmu_read(CPUMBState *env, bool ext, uint32_t rn)
 178 {
 179     MicroBlazeCPU *cpu = env_archcpu(env);
 180     unsigned int i;
 181     uint32_t r = 0;
 182
 183     if (cpu->cfg.mmu < 2 || !cpu->cfg.mmu_tlb_access) {
 184         qemu_log_mask(LOG_GUEST_ERROR, "MMU access on MMU-less system\n");
 185         return 0;
 186     }
 187     if (ext && rn != MMU_R_TLBLO) {
 188         qemu_log_mask(LOG_GUEST_ERROR, "Extended access only to TLBLO.\n");
 189         return 0;
 190     }
 191
 192     switch (rn) {
 193         /* Reads to HI/LO trig reads from the mmu rams.  */
 194         case MMU_R_TLBLO:
 195         case MMU_R_TLBHI:
 196             if (!(cpu->cfg.mmu_tlb_access & 1)) {
 197                 qemu_log_mask(LOG_GUEST_ERROR,
 198                               "Invalid access to MMU reg %d\n", rn);
 199                 return 0;
 200             }
 201
 202             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
 203             r = extract64(env->mmu.rams[rn & 1][i], ext * 32, 32);
 204             if (rn == MMU_R_TLBHI)
 205                 env->mmu.regs[MMU_R_PID] = env->mmu.tids[i];
 206             break;
 207         case MMU_R_PID:
 208         case MMU_R_ZPR:
 209             if (!(cpu->cfg.mmu_tlb_access & 1)) {
 210                 qemu_log_mask(LOG_GUEST_ERROR,
 211                               "Invalid access to MMU reg %d\n", rn);
 212                 return 0;
 213             }
 214             r = env->mmu.regs[rn];
 215             break;
 216         case MMU_R_TLBX:
 217             r = env->mmu.regs[rn];
 218             break;
 219         case MMU_R_TLBSX:
 220             qemu_log_mask(LOG_GUEST_ERROR, "TLBSX is write-only.\n");
 221             break;
 222         default:
 223             qemu_log_mask(LOG_GUEST_ERROR, "Invalid MMU register %d.\n", rn);
 224             break;
 225     }
 226     qemu_log_mask(CPU_LOG_MMU, "%s rn=%d=%x\n", __func__, rn, r);
 227     return r;
 228 }
 229
 230 void mmu_write(CPUMBState *env, bool ext, uint32_t rn, uint32_t v)
 231 {
 232     MicroBlazeCPU *cpu = env_archcpu(env);
 233     uint64_t tmp64;
 234     unsigned int i;
 235
 236     qemu_log_mask(CPU_LOG_MMU,
 237                   "%s rn=%d=%x old=%x\n", __func__, rn, v,
 238                   rn < 3 ? env->mmu.regs[rn] : env->mmu.regs[MMU_R_TLBX]);
 239
 240     if (cpu->cfg.mmu < 2 || !cpu->cfg.mmu_tlb_access) {
 241         qemu_log_mask(LOG_GUEST_ERROR, "MMU access on MMU-less system\n");
 242         return;
 243     }
 244     if (ext && rn != MMU_R_TLBLO) {
 245         qemu_log_mask(LOG_GUEST_ERROR, "Extended access only to TLBLO.\n");
 246         return;
 247     }
 248
 249     switch (rn) {
 250         /* Writes to HI/LO trig writes to the mmu rams.  */
 251         case MMU_R_TLBLO:
 252         case MMU_R_TLBHI:
 253             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
 254             if (rn == MMU_R_TLBHI) {
 255                 if (i < 3 && !(v & TLB_VALID) && qemu_loglevel_mask(~0))
 256                     qemu_log_mask(LOG_GUEST_ERROR,
 257                                   "invalidating index %x at pc=%x\n",
 258                                   i, env->pc);
 259                 env->mmu.tids[i] = env->mmu.regs[MMU_R_PID] & 0xff;
 260                 mmu_flush_idx(env, i);
 261             }
 262             tmp64 = env->mmu.rams[rn & 1][i];
 263             env->mmu.rams[rn & 1][i] = deposit64(tmp64, ext * 32, 32, v);
 264             break;
 265         case MMU_R_ZPR:
 266             if (cpu->cfg.mmu_tlb_access <= 1) {
 267                 qemu_log_mask(LOG_GUEST_ERROR,
 268                               "Invalid access to MMU reg %d\n", rn);
 269                 return;
 270             }
 271
 272             /* Changes to the zone protection reg flush the QEMU TLB.
 273                Fortunately, these are very uncommon.  */
 274             if (v != env->mmu.regs[rn]) {
 275                 tlb_flush(env_cpu(env));
 276             }
 277             env->mmu.regs[rn] = v;
 278             break;
 279         case MMU_R_PID:
 280             if (cpu->cfg.mmu_tlb_access <= 1) {
 281                 qemu_log_mask(LOG_GUEST_ERROR,
 282                               "Invalid access to MMU reg %d\n", rn);
 283                 return;
 284             }
 285
 286             if (v != env->mmu.regs[rn]) {
 287                 mmu_change_pid(env, v);
 288                 env->mmu.regs[rn] = v;
 289             }
 290             break;
 291         case MMU_R_TLBX:
 292             /* Bit 31 is read-only.  */
 293             env->mmu.regs[rn] = deposit32(env->mmu.regs[rn], 0, 31, v);
 294             break;
 295         case MMU_R_TLBSX:
 296         {
 297             MicroBlazeMMULookup lu;
 298             int hit;
 299
 300             if (cpu->cfg.mmu_tlb_access <= 1) {
 301                 qemu_log_mask(LOG_GUEST_ERROR,
 302                               "Invalid access to MMU reg %d\n", rn);
 303                 return;
 304             }
 305
 306             hit = mmu_translate(cpu, &lu, v & TLB_EPN_MASK,
 307                                 0, cpu_mmu_index(env, false));
 308             if (hit) {
 309                 env->mmu.regs[MMU_R_TLBX] = lu.idx;
 310             } else {
 311                 env->mmu.regs[MMU_R_TLBX] |= R_TBLX_MISS_MASK;
 312             }
 313             break;
 314         }
 315         default:
 316             qemu_log_mask(LOG_GUEST_ERROR, "Invalid MMU register %d.\n", rn);
 317             break;
 318    }
 319 }
 320
 321 void mmu_init(MicroBlazeMMU *mmu)
 322 {
 323     int i;
 324     for (i = 0; i < ARRAY_SIZE(mmu->regs); i++) {
 325         mmu->regs[i] = 0;
 326     }
 327 }