target/nios2/mmu.c

   1 /*
   2  * Altera Nios II MMU emulation for qemu.
   3  *
   4  * Copyright (C) 2012 Chris Wulff <crwulff@gmail.com>
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, see
  18  * <http://www.gnu.org/licenses/lgpl-2.1.html>
  19  */
  20
  21 #include "qemu/osdep.h"
  22 #include "qemu/qemu-print.h"
  23 #include "cpu.h"
  24 #include "exec/exec-all.h"
  25 #include "mmu.h"
  26 #include "exec/helper-proto.h"
  27 #include "trace/trace-target_nios2.h"
  28
  29
  30 /* rw - 0 = read, 1 = write, 2 = fetch.  */
  31 unsigned int mmu_translate(CPUNios2State *env,
  32                            Nios2MMULookup *lu,
  33                            target_ulong vaddr, int rw, int mmu_idx)
  34 {
  35     Nios2CPU *cpu = env_archcpu(env);
  36     int pid = FIELD_EX32(env->mmu.tlbmisc_wr, CR_TLBMISC, PID);
  37     int vpn = vaddr >> 12;
  38     int way, n_ways = cpu->tlb_num_ways;
  39
  40     for (way = 0; way < n_ways; way++) {
  41         uint32_t index = (way * n_ways) + (vpn & env->mmu.tlb_entry_mask);
  42         Nios2TLBEntry *entry = &env->mmu.tlb[index];
  43
  44         if (((entry->tag >> 12) != vpn) ||
  45             (((entry->tag & (1 << 11)) == 0) &&
  46             ((entry->tag & ((1 << cpu->pid_num_bits) - 1)) != pid))) {
  47             trace_nios2_mmu_translate_miss(vaddr, pid, index, entry->tag);
  48             continue;
  49         }
  50
  51         lu->vaddr = vaddr & TARGET_PAGE_MASK;
  52         lu->paddr = FIELD_EX32(entry->data, CR_TLBACC, PFN) << TARGET_PAGE_BITS;
  53         lu->prot = ((entry->data & CR_TLBACC_R) ? PAGE_READ : 0) |
  54                    ((entry->data & CR_TLBACC_W) ? PAGE_WRITE : 0) |
  55                    ((entry->data & CR_TLBACC_X) ? PAGE_EXEC : 0);
  56
  57         trace_nios2_mmu_translate_hit(vaddr, pid, index, lu->paddr, lu->prot);
  58         return 1;
  59     }
  60     return 0;
  61 }
  62
  63 static void mmu_flush_pid(CPUNios2State *env, uint32_t pid)
  64 {
  65     CPUState *cs = env_cpu(env);
  66     Nios2CPU *cpu = env_archcpu(env);
  67     int idx;
  68
  69     for (idx = 0; idx < cpu->tlb_num_entries; idx++) {
  70         Nios2TLBEntry *entry = &env->mmu.tlb[idx];
  71
  72         if ((entry->tag & (1 << 10)) && (!(entry->tag & (1 << 11))) &&
  73             ((entry->tag & ((1 << cpu->pid_num_bits) - 1)) == pid)) {
  74             uint32_t vaddr = entry->tag & TARGET_PAGE_MASK;
  75
  76             trace_nios2_mmu_flush_pid_hit(pid, idx, vaddr);
  77             tlb_flush_page(cs, vaddr);
  78         } else {
  79             trace_nios2_mmu_flush_pid_miss(pid, idx, entry->tag);
  80         }
  81     }
  82 }
  83
  84 void helper_mmu_write_tlbacc(CPUNios2State *env, uint32_t v)
  85 {
  86     CPUState *cs = env_cpu(env);
  87     Nios2CPU *cpu = env_archcpu(env);
  88
  89     trace_nios2_mmu_write_tlbacc(FIELD_EX32(v, CR_TLBACC, IG),
  90                                  (v & CR_TLBACC_C) ? 'C' : '.',
  91                                  (v & CR_TLBACC_R) ? 'R' : '.',
  92                                  (v & CR_TLBACC_W) ? 'W' : '.',
  93                                  (v & CR_TLBACC_X) ? 'X' : '.',
  94                                  (v & CR_TLBACC_G) ? 'G' : '.',
  95                                  FIELD_EX32(v, CR_TLBACC, PFN));
  96
  97     /* if tlbmisc.WE == 1 then trigger a TLB write on writes to TLBACC */
  98     if (env->ctrl[CR_TLBMISC] & CR_TLBMISC_WE) {
  99         int way = FIELD_EX32(env->ctrl[CR_TLBMISC], CR_TLBMISC, WAY);
 100         int vpn = FIELD_EX32(env->mmu.pteaddr_wr, CR_PTEADDR, VPN);
 101         int pid = FIELD_EX32(env->mmu.tlbmisc_wr, CR_TLBMISC, PID);
 102         int g = FIELD_EX32(v, CR_TLBACC, G);
 103         int valid = FIELD_EX32(vpn, CR_TLBACC, PFN) < 0xC0000;
 104         Nios2TLBEntry *entry =
 105             &env->mmu.tlb[(way * cpu->tlb_num_ways) +
 106                           (vpn & env->mmu.tlb_entry_mask)];
 107         uint32_t newTag = (vpn << 12) | (g << 11) | (valid << 10) | pid;
 108         uint32_t newData = v & (CR_TLBACC_C | CR_TLBACC_R | CR_TLBACC_W |
 109                                 CR_TLBACC_X | R_CR_TLBACC_PFN_MASK);
 110
 111         if ((entry->tag != newTag) || (entry->data != newData)) {
 112             if (entry->tag & (1 << 10)) {
 113                 /* Flush existing entry */
 114                 tlb_flush_page(cs, entry->tag & TARGET_PAGE_MASK);
 115             }
 116             entry->tag = newTag;
 117             entry->data = newData;
 118         }
 119         /* Auto-increment tlbmisc.WAY */
 120         env->ctrl[CR_TLBMISC] = FIELD_DP32(env->ctrl[CR_TLBMISC],
 121                                            CR_TLBMISC, WAY,
 122                                            (way + 1) & (cpu->tlb_num_ways - 1));
 123     }
 124
 125     /* Writes to TLBACC don't change the read-back value */
 126     env->mmu.tlbacc_wr = v;
 127 }
 128
 129 void helper_mmu_write_tlbmisc(CPUNios2State *env, uint32_t v)
 130 {
 131     Nios2CPU *cpu = env_archcpu(env);
 132     uint32_t new_pid = FIELD_EX32(v, CR_TLBMISC, PID);
 133     uint32_t old_pid = FIELD_EX32(env->mmu.tlbmisc_wr, CR_TLBMISC, PID);
 134     uint32_t way = FIELD_EX32(v, CR_TLBMISC, WAY);
 135
 136     trace_nios2_mmu_write_tlbmisc(way,
 137                                   (v & CR_TLBMISC_RD) ? 'R' : '.',
 138                                   (v & CR_TLBMISC_WE) ? 'W' : '.',
 139                                   (v & CR_TLBMISC_DBL) ? '2' : '.',
 140                                   (v & CR_TLBMISC_BAD) ? 'B' : '.',
 141                                   (v & CR_TLBMISC_PERM) ? 'P' : '.',
 142                                   (v & CR_TLBMISC_D) ? 'D' : '.',
 143                                   new_pid);
 144
 145     if (new_pid != old_pid) {
 146         mmu_flush_pid(env, old_pid);
 147     }
 148
 149     /* if tlbmisc.RD == 1 then trigger a TLB read on writes to TLBMISC */
 150     if (v & CR_TLBMISC_RD) {
 151         int vpn = FIELD_EX32(env->mmu.pteaddr_wr, CR_PTEADDR, VPN);
 152         Nios2TLBEntry *entry =
 153             &env->mmu.tlb[(way * cpu->tlb_num_ways) +
 154                           (vpn & env->mmu.tlb_entry_mask)];
 155
 156         env->ctrl[CR_TLBACC] &= R_CR_TLBACC_IG_MASK;
 157         env->ctrl[CR_TLBACC] |= entry->data;
 158         env->ctrl[CR_TLBACC] |= (entry->tag & (1 << 11)) ? CR_TLBACC_G : 0;
 159         env->ctrl[CR_TLBMISC] = FIELD_DP32(v, CR_TLBMISC, PID,
 160                                            entry->tag &
 161                                            ((1 << cpu->pid_num_bits) - 1));
 162         env->ctrl[CR_PTEADDR] = FIELD_DP32(env->ctrl[CR_PTEADDR],
 163                                            CR_PTEADDR, VPN,
 164                                            entry->tag >> TARGET_PAGE_BITS);
 165     } else {
 166         env->ctrl[CR_TLBMISC] = v;
 167     }
 168
 169     env->mmu.tlbmisc_wr = v;
 170 }
 171
 172 void helper_mmu_write_pteaddr(CPUNios2State *env, uint32_t v)
 173 {
 174     trace_nios2_mmu_write_pteaddr(FIELD_EX32(v, CR_PTEADDR, PTBASE),
 175                                   FIELD_EX32(v, CR_PTEADDR, VPN));
 176
 177     /* Writes to PTEADDR don't change the read-back VPN value */
 178     env->ctrl[CR_PTEADDR] = ((v & ~R_CR_PTEADDR_VPN_MASK) |
 179                              (env->ctrl[CR_PTEADDR] & R_CR_PTEADDR_VPN_MASK));
 180     env->mmu.pteaddr_wr = v;
 181 }
 182
 183 void mmu_init(CPUNios2State *env)
 184 {
 185     Nios2CPU *cpu = env_archcpu(env);
 186     Nios2MMU *mmu = &env->mmu;
 187
 188     mmu->tlb_entry_mask = (cpu->tlb_num_entries / cpu->tlb_num_ways) - 1;
 189     mmu->tlb = g_new0(Nios2TLBEntry, cpu->tlb_num_entries);
 190 }
 191
 192 void dump_mmu(CPUNios2State *env)
 193 {
 194     Nios2CPU *cpu = env_archcpu(env);
 195     int i;
 196
 197     qemu_printf("MMU: ways %d, entries %d, pid bits %d\n",
 198                 cpu->tlb_num_ways, cpu->tlb_num_entries,
 199                 cpu->pid_num_bits);
 200
 201     for (i = 0; i < cpu->tlb_num_entries; i++) {
 202         Nios2TLBEntry *entry = &env->mmu.tlb[i];
 203         qemu_printf("TLB[%d] = %08X %08X %c VPN %05X "
 204                     "PID %02X %c PFN %05X %c%c%c%c\n",
 205                     i, entry->tag, entry->data,
 206                     (entry->tag & (1 << 10)) ? 'V' : '-',
 207                     entry->tag >> 12,
 208                     entry->tag & ((1 << cpu->pid_num_bits) - 1),
 209                     (entry->tag & (1 << 11)) ? 'G' : '-',
 210                     FIELD_EX32(entry->data, CR_TLBACC, PFN),
 211                     (entry->data & CR_TLBACC_C) ? 'C' : '-',
 212                     (entry->data & CR_TLBACC_R) ? 'R' : '-',
 213                     (entry->data & CR_TLBACC_W) ? 'W' : '-',
 214                     (entry->data & CR_TLBACC_X) ? 'X' : '-');
 215     }
 216 }