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     CPUState *cs = CPU(mb_env_get_cpu(env));
  38     struct microblaze_mmu *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     struct microblaze_mmu *mmu = &env->mmu;
  59     unsigned int i;
  60     uint32_t t;
  61
  62     if (newpid & ~0xff)
  63         qemu_log("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(struct microblaze_mmu *mmu,
  77                            struct microblaze_mmu_lookup *lu,
  78                            target_ulong vaddr, int rw, int mmu_idx)
  79 {
  80     unsigned int i, hit = 0;
  81     unsigned int tlb_ex = 0, tlb_wr = 0, tlb_zsel;
  82     unsigned int tlb_size;
  83     uint32_t tlb_tag, tlb_rpn, mask, t0;
  84
  85     lu->err = ERR_MISS;
  86     for (i = 0; i < ARRAY_SIZE(mmu->rams[RAM_TAG]); i++) {
  87         uint32_t t, d;
  88
  89         /* Lookup and decode.  */
  90         t = mmu->rams[RAM_TAG][i];
  91         D(qemu_log("TLB %d valid=%d\n", i, t & TLB_VALID));
  92         if (t & TLB_VALID) {
  93             tlb_size = tlb_decode_size((t & TLB_PAGESZ_MASK) >> 7);
  94             if (tlb_size < TARGET_PAGE_SIZE) {
  95                 qemu_log("%d pages not supported\n", tlb_size);
  96                 abort();
  97             }
  98
  99             mask = ~(tlb_size - 1);
 100             tlb_tag = t & TLB_EPN_MASK;
 101             if ((vaddr & mask) != (tlb_tag & mask)) {
 102                 D(qemu_log("TLB %d vaddr=%x != tag=%x\n",
 103                            i, vaddr & mask, tlb_tag & mask));
 104                 continue;
 105             }
 106             if (mmu->tids[i]
 107                 && ((mmu->regs[MMU_R_PID] & 0xff) != mmu->tids[i])) {
 108                 D(qemu_log("TLB %d pid=%x != tid=%x\n",
 109                            i, mmu->regs[MMU_R_PID], mmu->tids[i]));
 110                 continue;
 111             }
 112
 113             /* Bring in the data part.  */
 114             d = mmu->rams[RAM_DATA][i];
 115             tlb_ex = d & TLB_EX;
 116             tlb_wr = d & TLB_WR;
 117
 118             /* Now let's see if there is a zone that overrides the protbits.  */
 119             tlb_zsel = (d >> 4) & 0xf;
 120             t0 = mmu->regs[MMU_R_ZPR] >> (30 - (tlb_zsel * 2));
 121             t0 &= 0x3;
 122
 123             if (tlb_zsel > mmu->c_mmu_zones) {
 124                 qemu_log("tlb zone select out of range! %d\n", tlb_zsel);
 125                 t0 = 1; /* Ignore.  */
 126             }
 127
 128             if (mmu->c_mmu == 1) {
 129                 t0 = 1; /* Zones are disabled.  */
 130             }
 131
 132             switch (t0) {
 133                 case 0:
 134                     if (mmu_idx == MMU_USER_IDX)
 135                         continue;
 136                     break;
 137                 case 2:
 138                     if (mmu_idx != MMU_USER_IDX) {
 139                         tlb_ex = 1;
 140                         tlb_wr = 1;
 141                     }
 142                     break;
 143                 case 3:
 144                     tlb_ex = 1;
 145                     tlb_wr = 1;
 146                     break;
 147                 default: break;
 148             }
 149
 150             lu->err = ERR_PROT;
 151             lu->prot = PAGE_READ;
 152             if (tlb_wr)
 153                 lu->prot |= PAGE_WRITE;
 154             else if (rw == 1)
 155                 goto done;
 156             if (tlb_ex)
 157                 lu->prot |=PAGE_EXEC;
 158             else if (rw == 2) {
 159                 goto done;
 160             }
 161
 162             tlb_rpn = d & TLB_RPN_MASK;
 163
 164             lu->vaddr = tlb_tag;
 165             lu->paddr = tlb_rpn;
 166             lu->size = tlb_size;
 167             lu->err = ERR_HIT;
 168             lu->idx = i;
 169             hit = 1;
 170             goto done;
 171         }
 172     }
 173 done:
 174     D(qemu_log("MMU vaddr=%x rw=%d tlb_wr=%d tlb_ex=%d hit=%d\n",
 175               vaddr, rw, tlb_wr, tlb_ex, hit));
 176     return hit;
 177 }
 178
 179 /* Writes/reads to the MMU's special regs end up here.  */
 180 uint32_t mmu_read(CPUMBState *env, uint32_t rn)
 181 {
 182     unsigned int i;
 183     uint32_t r;
 184
 185     if (env->mmu.c_mmu < 2 || !env->mmu.c_mmu_tlb_access) {
 186         qemu_log("MMU access on MMU-less system\n");
 187         return 0;
 188     }
 189
 190     switch (rn) {
 191         /* Reads to HI/LO trig reads from the mmu rams.  */
 192         case MMU_R_TLBLO:
 193         case MMU_R_TLBHI:
 194             if (!(env->mmu.c_mmu_tlb_access & 1)) {
 195                 qemu_log("Invalid access to MMU reg %d\n", rn);
 196                 return 0;
 197             }
 198
 199             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
 200             r = env->mmu.rams[rn & 1][i];
 201             if (rn == MMU_R_TLBHI)
 202                 env->mmu.regs[MMU_R_PID] = env->mmu.tids[i];
 203             break;
 204         case MMU_R_PID:
 205         case MMU_R_ZPR:
 206             if (!(env->mmu.c_mmu_tlb_access & 1)) {
 207                 qemu_log("Invalid access to MMU reg %d\n", rn);
 208                 return 0;
 209             }
 210             r = env->mmu.regs[rn];
 211             break;
 212         default:
 213             r = env->mmu.regs[rn];
 214             break;
 215     }
 216     D(qemu_log("%s rn=%d=%x\n", __func__, rn, r));
 217     return r;
 218 }
 219
 220 void mmu_write(CPUMBState *env, uint32_t rn, uint32_t v)
 221 {
 222     MicroBlazeCPU *cpu = mb_env_get_cpu(env);
 223     unsigned int i;
 224     D(qemu_log("%s rn=%d=%x old=%x\n", __func__, rn, v, env->mmu.regs[rn]));
 225
 226     if (env->mmu.c_mmu < 2 || !env->mmu.c_mmu_tlb_access) {
 227         qemu_log("MMU access on MMU-less system\n");
 228         return;
 229     }
 230
 231     switch (rn) {
 232         /* Writes to HI/LO trig writes to the mmu rams.  */
 233         case MMU_R_TLBLO:
 234         case MMU_R_TLBHI:
 235             i = env->mmu.regs[MMU_R_TLBX] & 0xff;
 236             if (rn == MMU_R_TLBHI) {
 237                 if (i < 3 && !(v & TLB_VALID) && qemu_loglevel_mask(~0))
 238                     qemu_log("invalidating index %x at pc=%x\n",
 239                              i, env->sregs[SR_PC]);
 240                 env->mmu.tids[i] = env->mmu.regs[MMU_R_PID] & 0xff;
 241                 mmu_flush_idx(env, i);
 242             }
 243             env->mmu.rams[rn & 1][i] = v;
 244
 245             D(qemu_log("%s ram[%d][%d]=%x\n", __func__, rn & 1, i, v));
 246             break;
 247         case MMU_R_ZPR:
 248             if (env->mmu.c_mmu_tlb_access <= 1) {
 249                 qemu_log("Invalid access to MMU reg %d\n", rn);
 250                 return;
 251             }
 252
 253             /* Changes to the zone protection reg flush the QEMU TLB.
 254                Fortunately, these are very uncommon.  */
 255             if (v != env->mmu.regs[rn]) {
 256                 tlb_flush(CPU(cpu), 1);
 257             }
 258             env->mmu.regs[rn] = v;
 259             break;
 260         case MMU_R_PID:
 261             if (env->mmu.c_mmu_tlb_access <= 1) {
 262                 qemu_log("Invalid access to MMU reg %d\n", rn);
 263                 return;
 264             }
 265
 266             if (v != env->mmu.regs[rn]) {
 267                 mmu_change_pid(env, v);
 268                 env->mmu.regs[rn] = v;
 269             }
 270             break;
 271         case MMU_R_TLBSX:
 272         {
 273             struct microblaze_mmu_lookup lu;
 274             int hit;
 275
 276             if (env->mmu.c_mmu_tlb_access <= 1) {
 277                 qemu_log("Invalid access to MMU reg %d\n", rn);
 278                 return;
 279             }
 280
 281             hit = mmu_translate(&env->mmu, &lu,
 282                                 v & TLB_EPN_MASK, 0, cpu_mmu_index(env));
 283             if (hit) {
 284                 env->mmu.regs[MMU_R_TLBX] = lu.idx;
 285             } else
 286                 env->mmu.regs[MMU_R_TLBX] |= 0x80000000;
 287             break;
 288         }
 289         default:
 290             env->mmu.regs[rn] = v;
 291             break;
 292    }
 293 }
 294
 295 void mmu_init(struct microblaze_mmu *mmu)
 296 {
 297     int i;
 298     for (i = 0; i < ARRAY_SIZE(mmu->regs); i++) {
 299         mmu->regs[i] = 0;
 300     }
 301 }