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 2.1 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 #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
  50     return f;
  51 }
  52
  53 static void cris_mmu_update_rand_lfsr(CPUCRISState *env)
  54 {
  55     unsigned int f;
  56
  57     /* Update lfsr at every fault.  */
  58     f = compute_polynom(env->mmu_rand_lfsr);
  59     env->mmu_rand_lfsr >>= 1;
  60     env->mmu_rand_lfsr |= (f << 15);
  61     env->mmu_rand_lfsr &= 0xffff;
  62 }
  63
  64 static inline int cris_mmu_enabled(uint32_t rw_gc_cfg)
  65 {
  66     return (rw_gc_cfg & 12) != 0;
  67 }
  68
  69 static inline int cris_mmu_segmented_addr(int seg, uint32_t rw_mm_cfg)
  70 {
  71     return (1 << seg) & rw_mm_cfg;
  72 }
  73
  74 static uint32_t cris_mmu_translate_seg(CPUCRISState *env, int seg)
  75 {
  76     uint32_t base;
  77     int i;
  78
  79     if (seg < 8) {
  80         base = env->sregs[SFR_RW_MM_KBASE_LO];
  81     } else {
  82         base = env->sregs[SFR_RW_MM_KBASE_HI];
  83     }
  84
  85     i = seg & 7;
  86     base >>= i * 4;
  87     base &= 15;
  88
  89     base <<= 28;
  90     return base;
  91 }
  92
  93 /* Used by the tlb decoder.  */
  94 #define EXTRACT_FIELD(src, start, end)                  \
  95     (((src) >> start) & ((1 << (end - start + 1)) - 1))
  96
  97 static inline void set_field(uint32_t *dst, unsigned int val,
  98                              unsigned int offset, unsigned int width)
  99 {
 100     uint32_t mask;
 101
 102     mask = (1 << width) - 1;
 103     mask <<= offset;
 104     val <<= offset;
 105
 106     val &= mask;
 107     *dst &= ~(mask);
 108     *dst |= val;
 109 }
 110
 111 #ifdef DEBUG
 112 static void dump_tlb(CPUCRISState *env, int mmu)
 113 {
 114     int set;
 115     int idx;
 116     uint32_t hi, lo, tlb_vpn, tlb_pfn;
 117
 118     for (set = 0; set < 4; set++) {
 119         for (idx = 0; idx < 16; idx++) {
 120             lo = env->tlbsets[mmu][set][idx].lo;
 121             hi = env->tlbsets[mmu][set][idx].hi;
 122             tlb_vpn = EXTRACT_FIELD(hi, 13, 31);
 123             tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
 124
 125             printf("TLB: [%d][%d] hi=%x lo=%x v=%x p=%x\n",
 126                    set, idx, hi, lo, tlb_vpn, tlb_pfn);
 127         }
 128     }
 129 }
 130 #endif
 131
 132 static int cris_mmu_translate_page(struct cris_mmu_result *res,
 133                                    CPUCRISState *env, uint32_t vaddr,
 134                                    MMUAccessType access_type,
 135                                    int usermode, int debug)
 136 {
 137     unsigned int vpage;
 138     unsigned int idx;
 139     uint32_t pid, lo, hi;
 140     uint32_t tlb_vpn, tlb_pfn = 0;
 141     int tlb_pid, tlb_g, tlb_v, tlb_k, tlb_w, tlb_x;
 142     int cfg_v, cfg_k, cfg_w, cfg_x;
 143     int set, match = 0;
 144     uint32_t r_cause;
 145     uint32_t r_cfg;
 146     int rwcause;
 147     int mmu = 1; /* Data mmu is default.  */
 148     int vect_base;
 149
 150     r_cause = env->sregs[SFR_R_MM_CAUSE];
 151     r_cfg = env->sregs[SFR_RW_MM_CFG];
 152     pid = env->pregs[PR_PID] & 0xff;
 153
 154     switch (access_type) {
 155     case MMU_INST_FETCH:
 156         rwcause = CRIS_MMU_ERR_EXEC;
 157         mmu = 0;
 158         break;
 159     case MMU_DATA_STORE:
 160         rwcause = CRIS_MMU_ERR_WRITE;
 161         break;
 162     default:
 163     case MMU_DATA_LOAD:
 164         rwcause = CRIS_MMU_ERR_READ;
 165         break;
 166     }
 167
 168     /* I exception vectors 4 - 7, D 8 - 11.  */
 169     vect_base = (mmu + 1) * 4;
 170
 171     vpage = vaddr >> 13;
 172
 173     /*
 174      * We know the index which to check on each set.
 175      * Scan both I and D.
 176      */
 177     idx = vpage & 15;
 178     for (set = 0; set < 4; set++) {
 179         lo = env->tlbsets[mmu][set][idx].lo;
 180         hi = env->tlbsets[mmu][set][idx].hi;
 181
 182         tlb_vpn = hi >> 13;
 183         tlb_pid = EXTRACT_FIELD(hi, 0, 7);
 184         tlb_g  = EXTRACT_FIELD(lo, 4, 4);
 185
 186         D_LOG("TLB[%d][%d][%d] v=%x vpage=%x lo=%x hi=%x\n",
 187               mmu, set, idx, tlb_vpn, vpage, lo, hi);
 188         if ((tlb_g || (tlb_pid == pid)) && tlb_vpn == vpage) {
 189             match = 1;
 190             break;
 191         }
 192     }
 193
 194     res->bf_vec = vect_base;
 195     if (match) {
 196         cfg_w  = EXTRACT_FIELD(r_cfg, 19, 19);
 197         cfg_k  = EXTRACT_FIELD(r_cfg, 18, 18);
 198         cfg_x  = EXTRACT_FIELD(r_cfg, 17, 17);
 199         cfg_v  = EXTRACT_FIELD(r_cfg, 16, 16);
 200
 201         tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
 202         tlb_v = EXTRACT_FIELD(lo, 3, 3);
 203         tlb_k = EXTRACT_FIELD(lo, 2, 2);
 204         tlb_w = EXTRACT_FIELD(lo, 1, 1);
 205         tlb_x = EXTRACT_FIELD(lo, 0, 0);
 206
 207         /*
 208          * set_exception_vector(0x04, i_mmu_refill);
 209          * set_exception_vector(0x05, i_mmu_invalid);
 210          * set_exception_vector(0x06, i_mmu_access);
 211          * set_exception_vector(0x07, i_mmu_execute);
 212          * set_exception_vector(0x08, d_mmu_refill);
 213          * set_exception_vector(0x09, d_mmu_invalid);
 214          * set_exception_vector(0x0a, d_mmu_access);
 215          * set_exception_vector(0x0b, d_mmu_write);
 216          */
 217         if (cfg_k && tlb_k && usermode) {
 218             D(printf("tlb: kernel protected %x lo=%x pc=%x\n",
 219                      vaddr, lo, env->pc));
 220             match = 0;
 221             res->bf_vec = vect_base + 2;
 222         } else if (access_type == MMU_DATA_STORE && cfg_w && !tlb_w) {
 223             D(printf("tlb: write protected %x lo=%x pc=%x\n",
 224                      vaddr, lo, env->pc));
 225             match = 0;
 226             /* write accesses never go through the I mmu.  */
 227             res->bf_vec = vect_base + 3;
 228         } else if (access_type == MMU_INST_FETCH && cfg_x && !tlb_x) {
 229             D(printf("tlb: exec protected %x lo=%x pc=%x\n",
 230                      vaddr, lo, env->pc));
 231             match = 0;
 232             res->bf_vec = vect_base + 3;
 233         } else if (cfg_v && !tlb_v) {
 234             D(printf("tlb: invalid %x\n", vaddr));
 235             match = 0;
 236             res->bf_vec = vect_base + 1;
 237         }
 238
 239         res->prot = 0;
 240         if (match) {
 241             res->prot |= PAGE_READ;
 242             if (tlb_w) {
 243                 res->prot |= PAGE_WRITE;
 244             }
 245             if (mmu == 0 && (cfg_x || tlb_x)) {
 246                 res->prot |= PAGE_EXEC;
 247             }
 248         } else {
 249             D(dump_tlb(env, mmu));
 250         }
 251     } else {
 252         /* If refill, provide a randomized set.  */
 253         set = env->mmu_rand_lfsr & 3;
 254     }
 255
 256     if (!match && !debug) {
 257         cris_mmu_update_rand_lfsr(env);
 258
 259         /* Compute index.  */
 260         idx = vpage & 15;
 261
 262         /* Update RW_MM_TLB_SEL.  */
 263         env->sregs[SFR_RW_MM_TLB_SEL] = 0;
 264         set_field(&env->sregs[SFR_RW_MM_TLB_SEL], idx, 0, 4);
 265         set_field(&env->sregs[SFR_RW_MM_TLB_SEL], set, 4, 2);
 266
 267         /* Update RW_MM_CAUSE.  */
 268         set_field(&r_cause, rwcause, 8, 2);
 269         set_field(&r_cause, vpage, 13, 19);
 270         set_field(&r_cause, pid, 0, 8);
 271         env->sregs[SFR_R_MM_CAUSE] = r_cause;
 272         D(printf("refill vaddr=%x pc=%x\n", vaddr, env->pc));
 273     }
 274
 275     D(printf("%s access=%u mtch=%d pc=%x va=%x vpn=%x tlbvpn=%x pfn=%x pid=%x"
 276              " %x cause=%x sel=%x sp=%x %x %x\n",
 277              __func__, access_type, match, env->pc,
 278              vaddr, vpage,
 279              tlb_vpn, tlb_pfn, tlb_pid,
 280              pid,
 281              r_cause,
 282              env->sregs[SFR_RW_MM_TLB_SEL],
 283              env->regs[R_SP], env->pregs[PR_USP], env->ksp));
 284
 285     res->phy = tlb_pfn << TARGET_PAGE_BITS;
 286     return !match;
 287 }
 288
 289 void cris_mmu_flush_pid(CPUCRISState *env, uint32_t pid)
 290 {
 291     target_ulong vaddr;
 292     unsigned int idx;
 293     uint32_t lo, hi;
 294     uint32_t tlb_vpn;
 295     int tlb_pid, tlb_g, tlb_v;
 296     unsigned int set;
 297     unsigned int mmu;
 298
 299     pid &= 0xff;
 300     for (mmu = 0; mmu < 2; mmu++) {
 301         for (set = 0; set < 4; set++) {
 302             for (idx = 0; idx < 16; idx++) {
 303                 lo = env->tlbsets[mmu][set][idx].lo;
 304                 hi = env->tlbsets[mmu][set][idx].hi;
 305
 306                 tlb_vpn = EXTRACT_FIELD(hi, 13, 31);
 307                 tlb_pid = EXTRACT_FIELD(hi, 0, 7);
 308                 tlb_g  = EXTRACT_FIELD(lo, 4, 4);
 309                 tlb_v = EXTRACT_FIELD(lo, 3, 3);
 310
 311                 if (tlb_v && !tlb_g && (tlb_pid == pid)) {
 312                     vaddr = tlb_vpn << TARGET_PAGE_BITS;
 313                     D_LOG("flush pid=%x vaddr=%x\n", pid, vaddr);
 314                     tlb_flush_page(env_cpu(env), vaddr);
 315                 }
 316             }
 317         }
 318     }
 319 }
 320
 321 int cris_mmu_translate(struct cris_mmu_result *res,
 322                        CPUCRISState *env, uint32_t vaddr,
 323                        MMUAccessType access_type, int mmu_idx, int debug)
 324 {
 325     int seg;
 326     int miss = 0;
 327     int is_user = mmu_idx == MMU_USER_IDX;
 328     uint32_t old_srs;
 329
 330     old_srs = env->pregs[PR_SRS];
 331
 332     env->pregs[PR_SRS] = access_type == MMU_INST_FETCH ? 1 : 2;
 333
 334     if (!cris_mmu_enabled(env->sregs[SFR_RW_GC_CFG])) {
 335         res->phy = vaddr;
 336         res->prot = PAGE_BITS;
 337         goto done;
 338     }
 339
 340     seg = vaddr >> 28;
 341     if (!is_user && cris_mmu_segmented_addr(seg, env->sregs[SFR_RW_MM_CFG])) {
 342         uint32_t base;
 343
 344         miss = 0;
 345         base = cris_mmu_translate_seg(env, seg);
 346         res->phy = base | (0x0fffffff & vaddr);
 347         res->prot = PAGE_BITS;
 348     } else {
 349         miss = cris_mmu_translate_page(res, env, vaddr, access_type,
 350                                        is_user, debug);
 351     }
 352  done:
 353     env->pregs[PR_SRS] = old_srs;
 354     return miss;
 355 }