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, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 #ifndef CONFIG_USER_ONLY
  23
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <stdlib.h>
  27
  28 #include "config.h"
  29 #include "cpu.h"
  30 #include "mmu.h"
  31 #include "exec-all.h"
  32
  33 #define D(x)
  34
  35 void cris_mmu_init(CPUState *env)
  36 {
  37         env->mmu_rand_lfsr = 0xcccc;
  38 }
  39
  40 #define SR_POLYNOM 0x8805
  41 static inline unsigned int compute_polynom(unsigned int sr)
  42 {
  43         unsigned int i;
  44         unsigned int f;
  45
  46         f = 0;
  47         for (i = 0; i < 16; i++)
  48                 f += ((SR_POLYNOM >> i) & 1) & ((sr >> i) & 1);
  49
  50         return f;
  51 }
  52
  53 static inline int cris_mmu_enabled(uint32_t rw_gc_cfg)
  54 {
  55         return (rw_gc_cfg & 12) != 0;
  56 }
  57
  58 static inline int cris_mmu_segmented_addr(int seg, uint32_t rw_mm_cfg)
  59 {
  60         return (1 << seg) & rw_mm_cfg;
  61 }
  62
  63 static uint32_t cris_mmu_translate_seg(CPUState *env, int seg)
  64 {
  65         uint32_t base;
  66         int i;
  67
  68         if (seg < 8)
  69                 base = env->sregs[SFR_RW_MM_KBASE_LO];
  70         else
  71                 base = env->sregs[SFR_RW_MM_KBASE_HI];
  72
  73         i = seg & 7;
  74         base >>= i * 4;
  75         base &= 15;
  76
  77         base <<= 28;
  78         return base;
  79 }
  80 /* Used by the tlb decoder.  */
  81 #define EXTRACT_FIELD(src, start, end) \
  82             (((src) >> start) & ((1 << (end - start + 1)) - 1))
  83
  84 static inline void set_field(uint32_t *dst, unsigned int val,
  85                              unsigned int offset, unsigned int width)
  86 {
  87         uint32_t mask;
  88
  89         mask = (1 << width) - 1;
  90         mask <<= offset;
  91         val <<= offset;
  92
  93         val &= mask;
  94         *dst &= ~(mask);
  95         *dst |= val;
  96 }
  97
  98 static void dump_tlb(CPUState *env, int mmu)
  99 {
 100         int set;
 101         int idx;
 102         uint32_t hi, lo, tlb_vpn, tlb_pfn;
 103
 104         for (set = 0; set < 4; set++) {
 105                 for (idx = 0; idx < 16; idx++) {
 106                         lo = env->tlbsets[mmu][set][idx].lo;
 107                         hi = env->tlbsets[mmu][set][idx].hi;
 108                         tlb_vpn = EXTRACT_FIELD(hi, 13, 31);
 109                         tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
 110
 111                         printf ("TLB: [%d][%d] hi=%x lo=%x v=%x p=%x\n",
 112                                         set, idx, hi, lo, tlb_vpn, tlb_pfn);
 113                 }
 114         }
 115 }
 116
 117 /* rw 0 = read, 1 = write, 2 = exec.  */
 118 static int cris_mmu_translate_page(struct cris_mmu_result_t *res,
 119                                    CPUState *env, uint32_t vaddr,
 120                                    int rw, int usermode)
 121 {
 122         unsigned int vpage;
 123         unsigned int idx;
 124         uint32_t lo, hi;
 125         uint32_t tlb_vpn, tlb_pfn = 0;
 126         int tlb_pid, tlb_g, tlb_v, tlb_k, tlb_w, tlb_x;
 127         int cfg_v, cfg_k, cfg_w, cfg_x;
 128         int set, match = 0;
 129         uint32_t r_cause;
 130         uint32_t r_cfg;
 131         int rwcause;
 132         int mmu = 1; /* Data mmu is default.  */
 133         int vect_base;
 134
 135         r_cause = env->sregs[SFR_R_MM_CAUSE];
 136         r_cfg = env->sregs[SFR_RW_MM_CFG];
 137
 138         switch (rw) {
 139                 case 2: rwcause = CRIS_MMU_ERR_EXEC; mmu = 0; break;
 140                 case 1: rwcause = CRIS_MMU_ERR_WRITE; break;
 141                 default:
 142                 case 0: rwcause = CRIS_MMU_ERR_READ; break;
 143         }
 144
 145         /* I exception vectors 4 - 7, D 8 - 11.  */
 146         vect_base = (mmu + 1) * 4;
 147
 148         vpage = vaddr >> 13;
 149
 150         /* We know the index which to check on each set.
 151            Scan both I and D.  */
 152 #if 0
 153         for (set = 0; set < 4; set++) {
 154                 for (idx = 0; idx < 16; idx++) {
 155                         lo = env->tlbsets[mmu][set][idx].lo;
 156                         hi = env->tlbsets[mmu][set][idx].hi;
 157                         tlb_vpn = EXTRACT_FIELD(hi, 13, 31);
 158                         tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
 159
 160                         printf ("TLB: [%d][%d] hi=%x lo=%x v=%x p=%x\n",
 161                                         set, idx, hi, lo, tlb_vpn, tlb_pfn);
 162                 }
 163         }
 164 #endif
 165
 166         idx = vpage & 15;
 167         for (set = 0; set < 4; set++)
 168         {
 169                 lo = env->tlbsets[mmu][set][idx].lo;
 170                 hi = env->tlbsets[mmu][set][idx].hi;
 171
 172                 tlb_vpn = EXTRACT_FIELD(hi, 13, 31);
 173                 tlb_pid = EXTRACT_FIELD(hi, 0, 7);
 174                 tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
 175                 tlb_g  = EXTRACT_FIELD(lo, 4, 4);
 176
 177                 D(printf("TLB[%d][%d] v=%x vpage=%x -> pfn=%x lo=%x hi=%x\n",
 178                                 i, idx, tlb_vpn, vpage, tlb_pfn, lo, hi));
 179                 if ((tlb_g || (tlb_pid == (env->pregs[PR_PID] & 0xff)))
 180                     && tlb_vpn == vpage) {
 181                         match = 1;
 182                         break;
 183                 }
 184         }
 185
 186         res->bf_vec = vect_base;
 187         if (match) {
 188                 cfg_w  = EXTRACT_FIELD(r_cfg, 19, 19);
 189                 cfg_k  = EXTRACT_FIELD(r_cfg, 18, 18);
 190                 cfg_x  = EXTRACT_FIELD(r_cfg, 17, 17);
 191                 cfg_v  = EXTRACT_FIELD(r_cfg, 16, 16);
 192
 193                 tlb_pfn = EXTRACT_FIELD(lo, 13, 31);
 194                 tlb_v = EXTRACT_FIELD(lo, 3, 3);
 195                 tlb_k = EXTRACT_FIELD(lo, 2, 2);
 196                 tlb_w = EXTRACT_FIELD(lo, 1, 1);
 197                 tlb_x = EXTRACT_FIELD(lo, 0, 0);
 198
 199                 /*
 200                 set_exception_vector(0x04, i_mmu_refill);
 201                 set_exception_vector(0x05, i_mmu_invalid);
 202                 set_exception_vector(0x06, i_mmu_access);
 203                 set_exception_vector(0x07, i_mmu_execute);
 204                 set_exception_vector(0x08, d_mmu_refill);
 205                 set_exception_vector(0x09, d_mmu_invalid);
 206                 set_exception_vector(0x0a, d_mmu_access);
 207                 set_exception_vector(0x0b, d_mmu_write);
 208                 */
 209                 if (cfg_k && tlb_k && usermode) {
 210                         D(printf ("tlb: kernel protected %x lo=%x pc=%x\n",
 211                                   vaddr, lo, env->pc));
 212                         match = 0;
 213                         res->bf_vec = vect_base + 2;
 214                 } else if (rw == 1 && cfg_w && !tlb_w) {
 215                         D(printf ("tlb: write protected %x lo=%x pc=%x\n",
 216                                   vaddr, lo, env->pc));
 217                         match = 0;
 218                         /* write accesses never go through the I mmu.  */
 219                         res->bf_vec = vect_base + 3;
 220                 } else if (rw == 2 && cfg_x && !tlb_x) {
 221                         D(printf ("tlb: exec protected %x lo=%x pc=%x\n",
 222                                  vaddr, lo, env->pc));
 223                         match = 0;
 224                         res->bf_vec = vect_base + 3;
 225                 } else if (cfg_v && !tlb_v) {
 226                         D(printf ("tlb: invalid %x\n", vaddr));
 227                         set_field(&r_cause, rwcause, 8, 9);
 228                         match = 0;
 229                         res->bf_vec = vect_base + 1;
 230                 }
 231
 232                 res->prot = 0;
 233                 if (match) {
 234                         res->prot |= PAGE_READ;
 235                         if (tlb_w)
 236                                 res->prot |= PAGE_WRITE;
 237                         if (tlb_x)
 238                                 res->prot |= PAGE_EXEC;
 239                 }
 240                 else
 241                         D(dump_tlb(env, mmu));
 242
 243                 env->sregs[SFR_RW_MM_TLB_HI] = hi;
 244                 env->sregs[SFR_RW_MM_TLB_LO] = lo;
 245         } else {
 246                 /* If refill, provide a randomized set.  */
 247                 set = env->mmu_rand_lfsr & 3;
 248         }
 249
 250         if (!match) {
 251                 unsigned int f;
 252
 253                 /* Update lfsr at every fault.  */
 254                 f = compute_polynom(env->mmu_rand_lfsr);
 255                 env->mmu_rand_lfsr >>= 1;
 256                 env->mmu_rand_lfsr |= (f << 15);
 257                 env->mmu_rand_lfsr &= 0xffff;
 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, env->pregs[PR_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
 276         D(printf ("%s rw=%d mtch=%d pc=%x va=%x vpn=%x tlbvpn=%x pfn=%x pid=%x"
 277                   " %x cause=%x sel=%x sp=%x %x %x\n",
 278                   __func__, rw, match, env->pc,
 279                   vaddr, vpage,
 280                   tlb_vpn, tlb_pfn, tlb_pid,
 281                   env->pregs[PR_PID],
 282                   r_cause,
 283                   env->sregs[SFR_RW_MM_TLB_SEL],
 284                   env->regs[R_SP], env->pregs[PR_USP], env->ksp));
 285
 286         res->pfn = tlb_pfn;
 287         return !match;
 288 }
 289
 290 /* Give us the vaddr corresponding to the latest TLB update.  */
 291 target_ulong cris_mmu_tlb_latest_update(CPUState *env)
 292 {
 293         uint32_t sel = env->sregs[SFR_RW_MM_TLB_SEL];
 294         uint32_t vaddr;
 295         uint32_t hi;
 296         int set;
 297         int idx;
 298
 299         idx = EXTRACT_FIELD(sel, 0, 4);
 300         set = EXTRACT_FIELD(sel, 4, 5);
 301
 302         hi = env->tlbsets[1][set][idx].hi;
 303         vaddr = EXTRACT_FIELD(hi, 13, 31);
 304         return vaddr << TARGET_PAGE_BITS;
 305 }
 306
 307 int cris_mmu_translate(struct cris_mmu_result_t *res,
 308                        CPUState *env, uint32_t vaddr,
 309                        int rw, int mmu_idx)
 310 {
 311         uint32_t phy = vaddr;
 312         int seg;
 313         int miss = 0;
 314         int is_user = mmu_idx == MMU_USER_IDX;
 315         uint32_t old_srs;
 316
 317         old_srs= env->pregs[PR_SRS];
 318
 319         /* rw == 2 means exec, map the access to the insn mmu.  */
 320         env->pregs[PR_SRS] = rw == 2 ? 1 : 2;
 321
 322         if (!cris_mmu_enabled(env->sregs[SFR_RW_GC_CFG])) {
 323                 res->phy = vaddr;
 324                 res->prot = PAGE_BITS;
 325                 goto done;
 326         }
 327
 328         seg = vaddr >> 28;
 329         if (cris_mmu_segmented_addr(seg, env->sregs[SFR_RW_MM_CFG]))
 330         {
 331                 uint32_t base;
 332
 333                 miss = 0;
 334                 base = cris_mmu_translate_seg(env, seg);
 335                 phy = base | (0x0fffffff & vaddr);
 336                 res->phy = phy;
 337                 res->prot = PAGE_BITS;
 338         }
 339         else
 340         {
 341                 miss = cris_mmu_translate_page(res, env, vaddr, rw, is_user);
 342                 phy = (res->pfn << 13);
 343                 res->phy = phy;
 344         }
 345   done:
 346         env->pregs[PR_SRS] = old_srs;
 347         return miss;
 348 }
 349 #endif