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