target-cris/mmu.c

   1 /*
   2  *  CRIS mmu emulation.
   3  *
   4  *  Copyright (c) 2007 AXIS Communications AB
   5  *  Written by Edgar E. Iglesias.
   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 "qemu/osdep.h"
  22 #include "cpu.h"
  23 #include "exec/exec-all.h"
  24 #include "mmu.h"
  25
  26 #ifdef DEBUG
  27 #define D(x) x
  28 #define D_LOG(...) qemu_log(__VA_ARGS__)
  29 #else
  30 #define D(x) do { } while (0)
  31 #define D_LOG(...) do { } while (0)
  32 #endif
  33
  34 void cris_mmu_init(CPUCRISState *env)
  35 {
  36         env->mmu_rand_lfsr = 0xcccc;
  37 }
  38
  39 #define SR_POLYNOM 0x8805
  40 static inline unsigned int compute_polynom(unsigned int sr)
  41 {
  42         unsigned int i;
  43         unsigned int f;
  44
  45         f = 0;
  46         for (i = 0; i < 16; i++)
  47                 f += ((SR_POLYNOM >> i) & 1) & ((sr >> i) & 1);
  48
  49         return f;
  50 }
  51
  52 static void cris_mmu_update_rand_lfsr(CPUCRISState *env)
  53 {
  54         unsigned int f;
  55
  56         /* Update lfsr at every fault.  */
  57         f = compute_polynom(env->mmu_rand_lfsr);
  58         env->mmu_rand_lfsr >>= 1;
  59         env->mmu_rand_lfsr |= (f << 15);
  60         env->mmu_rand_lfsr &= 0xffff;
  61 }
  62
  63 static inline int cris_mmu_enabled(uint32_t rw_gc_cfg)
  64 {
  65         return (rw_gc_cfg & 12) != 0;
  66 }
  67
  68 static inline int cris_mmu_segmented_addr(int seg, uint32_t rw_mm_cfg)
  69 {
  70         return (1 << seg) & rw_mm_cfg;
  71 }
  72
  73 static uint32_t cris_mmu_translate_seg(CPUCRISState *env, int seg)
  74 {
  75         uint32_t base;
  76         int i;
  77
  78         if (seg < 8)
  79                 base = env->sregs[SFR_RW_MM_KBASE_LO];
  80         else
  81                 base = env->sregs[SFR_RW_MM_KBASE_HI];
  82
  83         i = seg & 7;
  84         base >>= i * 4;
  85         base &= 15;
  86
  87         base <<= 28;
  88         return base;
  89 }
  90 /* Used by the tlb decoder.  */
  91 #define EXTRACT_FIELD(src, start, end) \
  92             (((src) >> start) & ((1 << (end - start + 1)) - 1))
  93
  94 static inline void set_field(uint32_t *dst, unsigned int val,
  95                              unsigned int offset, unsigned int width)
  96 {
  97         uint32_t mask;
  98
  99         mask = (1 << width) - 1;
 100         mask <<= offset;
 101         val <<= offset;
 102
 103         val &= mask;
 104         *dst &= ~(mask);
 105         *dst |= val;
 106 }
 107
 108 #ifdef DEBUG
 109 static void dump_tlb(CPUCRISState *env, int mmu)
 110 {
 111         int set;
 112         int idx;
 113         uint32_t hi, lo, tlb_vpn, tlb_pfn;
 114
 115         for (set = 0; set < 4; set++) {
 116                 for (idx = 0; idx < 16; idx++) {
 117                         lo = env->tlbsets[mmu][set][idx].lo;
 118                         hi = env->tlbsets[mmu][set][idx].hi;
 119                         tlb_vpn = EXTRACT_FIELD(hi, 13, 31);
 120                         tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
 121
 122                         printf ("TLB: [%d][%d] hi=%x lo=%x v=%x p=%x\n",
 123                                         set, idx, hi, lo, tlb_vpn, tlb_pfn);
 124                 }
 125         }
 126 }
 127 #endif
 128
 129 /* rw 0 = read, 1 = write, 2 = exec.  */
 130 static int cris_mmu_translate_page(struct cris_mmu_result *res,
 131                                    CPUCRISState *env, uint32_t vaddr,
 132                                    int rw, int usermode, int debug)
 133 {
 134         unsigned int vpage;
 135         unsigned int idx;
 136         uint32_t pid, lo, hi;
 137         uint32_t tlb_vpn, tlb_pfn = 0;
 138         int tlb_pid, tlb_g, tlb_v, tlb_k, tlb_w, tlb_x;
 139         int cfg_v, cfg_k, cfg_w, cfg_x;
 140         int set, match = 0;
 141         uint32_t r_cause;
 142         uint32_t r_cfg;
 143         int rwcause;
 144         int mmu = 1; /* Data mmu is default.  */
 145         int vect_base;
 146
 147         r_cause = env->sregs[SFR_R_MM_CAUSE];
 148         r_cfg = env->sregs[SFR_RW_MM_CFG];
 149         pid = env->pregs[PR_PID] & 0xff;
 150
 151         switch (rw) {
 152                 case 2: rwcause = CRIS_MMU_ERR_EXEC; mmu = 0; break;
 153                 case 1: rwcause = CRIS_MMU_ERR_WRITE; break;
 154                 default:
 155                 case 0: rwcause = CRIS_MMU_ERR_READ; break;
 156         }
 157
 158         /* I exception vectors 4 - 7, D 8 - 11.  */
 159         vect_base = (mmu + 1) * 4;
 160
 161         vpage = vaddr >> 13;
 162
 163         /* We know the index which to check on each set.
 164            Scan both I and D.  */
 165 #if 0
 166         for (set = 0; set < 4; set++) {
 167                 for (idx = 0; idx < 16; idx++) {
 168                         lo = env->tlbsets[mmu][set][idx].lo;
 169                         hi = env->tlbsets[mmu][set][idx].hi;
 170                         tlb_vpn = EXTRACT_FIELD(hi, 13, 31);
 171                         tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
 172
 173                         printf ("TLB: [%d][%d] hi=%x lo=%x v=%x p=%x\n",
 174                                         set, idx, hi, lo, tlb_vpn, tlb_pfn);
 175                 }
 176         }
 177 #endif
 178
 179         idx = vpage & 15;
 180         for (set = 0; set < 4; set++)
 181         {
 182                 lo = env->tlbsets[mmu][set][idx].lo;
 183                 hi = env->tlbsets[mmu][set][idx].hi;
 184
 185                 tlb_vpn = hi >> 13;
 186                 tlb_pid = EXTRACT_FIELD(hi, 0, 7);
 187                 tlb_g  = EXTRACT_FIELD(lo, 4, 4);
 188
 189                 D_LOG("TLB[%d][%d][%d] v=%x vpage=%x lo=%x hi=%x\n",
 190                          mmu, set, idx, tlb_vpn, vpage, lo, hi);
 191                 if ((tlb_g || (tlb_pid == pid))
 192                     && tlb_vpn == vpage) {
 193                         match = 1;
 194                         break;
 195                 }
 196         }
 197
 198         res->bf_vec = vect_base;
 199         if (match) {
 200                 cfg_w  = EXTRACT_FIELD(r_cfg, 19, 19);
 201                 cfg_k  = EXTRACT_FIELD(r_cfg, 18, 18);
 202                 cfg_x  = EXTRACT_FIELD(r_cfg, 17, 17);
 203                 cfg_v  = EXTRACT_FIELD(r_cfg, 16, 16);
 204
 205                 tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
 206                 tlb_v = EXTRACT_FIELD(lo, 3, 3);
 207                 tlb_k = EXTRACT_FIELD(lo, 2, 2);
 208                 tlb_w = EXTRACT_FIELD(lo, 1, 1);
 209                 tlb_x = EXTRACT_FIELD(lo, 0, 0);
 210
 211                 /*
 212                 set_exception_vector(0x04, i_mmu_refill);
 213                 set_exception_vector(0x05, i_mmu_invalid);
 214                 set_exception_vector(0x06, i_mmu_access);
 215                 set_exception_vector(0x07, i_mmu_execute);
 216                 set_exception_vector(0x08, d_mmu_refill);
 217                 set_exception_vector(0x09, d_mmu_invalid);
 218                 set_exception_vector(0x0a, d_mmu_access);
 219                 set_exception_vector(0x0b, d_mmu_write);
 220                 */
 221                 if (cfg_k && tlb_k && usermode) {
 222                         D(printf ("tlb: kernel protected %x lo=%x pc=%x\n",
 223                                   vaddr, lo, env->pc));
 224                         match = 0;
 225                         res->bf_vec = vect_base + 2;
 226                 } else if (rw == 1 && cfg_w && !tlb_w) {
 227                         D(printf ("tlb: write protected %x lo=%x pc=%x\n",
 228                                   vaddr, lo, env->pc));
 229                         match = 0;
 230                         /* write accesses never go through the I mmu.  */
 231                         res->bf_vec = vect_base + 3;
 232                 } else if (rw == 2 && cfg_x && !tlb_x) {
 233                         D(printf ("tlb: exec protected %x lo=%x pc=%x\n",
 234                                  vaddr, lo, env->pc));
 235                         match = 0;
 236                         res->bf_vec = vect_base + 3;
 237                 } else if (cfg_v && !tlb_v) {
 238                         D(printf ("tlb: invalid %x\n", vaddr));
 239                         match = 0;
 240                         res->bf_vec = vect_base + 1;
 241                 }
 242
 243                 res->prot = 0;
 244                 if (match) {
 245                         res->prot |= PAGE_READ;
 246                         if (tlb_w)
 247                                 res->prot |= PAGE_WRITE;
 248                         if (mmu == 0 && (cfg_x || tlb_x))
 249                                 res->prot |= PAGE_EXEC;
 250                 }
 251                 else
 252                         D(dump_tlb(env, mmu));
 253         } else {
 254                 /* If refill, provide a randomized set.  */
 255                 set = env->mmu_rand_lfsr & 3;
 256         }
 257
 258         if (!match && !debug) {
 259                 cris_mmu_update_rand_lfsr(env);
 260
 261                 /* Compute index.  */
 262                 idx = vpage & 15;
 263
 264                 /* Update RW_MM_TLB_SEL.  */
 265                 env->sregs[SFR_RW_MM_TLB_SEL] = 0;
 266                 set_field(&env->sregs[SFR_RW_MM_TLB_SEL], idx, 0, 4);
 267                 set_field(&env->sregs[SFR_RW_MM_TLB_SEL], set, 4, 2);
 268
 269                 /* Update RW_MM_CAUSE.  */
 270                 set_field(&r_cause, rwcause, 8, 2);
 271                 set_field(&r_cause, vpage, 13, 19);
 272                 set_field(&r_cause, pid, 0, 8);
 273                 env->sregs[SFR_R_MM_CAUSE] = r_cause;
 274                 D(printf("refill vaddr=%x pc=%x\n", vaddr, env->pc));
 275         }
 276
 277         D(printf ("%s rw=%d mtch=%d pc=%x va=%x vpn=%x tlbvpn=%x pfn=%x pid=%x"
 278                   " %x cause=%x sel=%x sp=%x %x %x\n",
 279                   __func__, rw, match, env->pc,
 280                   vaddr, vpage,
 281                   tlb_vpn, tlb_pfn, tlb_pid,
 282                   pid,
 283                   r_cause,
 284                   env->sregs[SFR_RW_MM_TLB_SEL],
 285                   env->regs[R_SP], env->pregs[PR_USP], env->ksp));
 286
 287         res->phy = tlb_pfn << TARGET_PAGE_BITS;
 288         return !match;
 289 }
 290
 291 void cris_mmu_flush_pid(CPUCRISState *env, uint32_t pid)
 292 {
 293     CRISCPU *cpu = cris_env_get_cpu(env);
 294         target_ulong vaddr;
 295         unsigned int idx;
 296         uint32_t lo, hi;
 297         uint32_t tlb_vpn;
 298         int tlb_pid, tlb_g, tlb_v;
 299         unsigned int set;
 300         unsigned int mmu;
 301
 302         pid &= 0xff;
 303         for (mmu = 0; mmu < 2; mmu++) {
 304                 for (set = 0; set < 4; set++)
 305                 {
 306                         for (idx = 0; idx < 16; idx++) {
 307                                 lo = env->tlbsets[mmu][set][idx].lo;
 308                                 hi = env->tlbsets[mmu][set][idx].hi;
 309
 310                                 tlb_vpn = EXTRACT_FIELD(hi, 13, 31);
 311                                 tlb_pid = EXTRACT_FIELD(hi, 0, 7);
 312                                 tlb_g  = EXTRACT_FIELD(lo, 4, 4);
 313                                 tlb_v = EXTRACT_FIELD(lo, 3, 3);
 314
 315                                 if (tlb_v && !tlb_g && (tlb_pid == pid)) {
 316                                         vaddr = tlb_vpn << TARGET_PAGE_BITS;
 317                                         D_LOG("flush pid=%x vaddr=%x\n",
 318                                                   pid, vaddr);
 319                     tlb_flush_page(CPU(cpu), vaddr);
 320                                 }
 321                         }
 322                 }
 323         }
 324 }
 325
 326 int cris_mmu_translate(struct cris_mmu_result *res,
 327                        CPUCRISState *env, uint32_t vaddr,
 328                        int rw, int mmu_idx, int debug)
 329 {
 330         int seg;
 331         int miss = 0;
 332         int is_user = mmu_idx == MMU_USER_IDX;
 333         uint32_t old_srs;
 334
 335         old_srs= env->pregs[PR_SRS];
 336
 337         /* rw == 2 means exec, map the access to the insn mmu.  */
 338         env->pregs[PR_SRS] = rw == 2 ? 1 : 2;
 339
 340         if (!cris_mmu_enabled(env->sregs[SFR_RW_GC_CFG])) {
 341                 res->phy = vaddr;
 342                 res->prot = PAGE_BITS;
 343                 goto done;
 344         }
 345
 346         seg = vaddr >> 28;
 347         if (!is_user && cris_mmu_segmented_addr(seg, env->sregs[SFR_RW_MM_CFG]))
 348         {
 349                 uint32_t base;
 350
 351                 miss = 0;
 352                 base = cris_mmu_translate_seg(env, seg);
 353                 res->phy = base | (0x0fffffff & vaddr);
 354                 res->prot = PAGE_BITS;
 355         } else {
 356                 miss = cris_mmu_translate_page(res, env, vaddr, rw,
 357                                                is_user, debug);
 358         }
 359   done:
 360         env->pregs[PR_SRS] = old_srs;
 361         return miss;
 362 }