target-openrisc/mmu.c

   1 /*
   2  * OpenRISC MMU.
   3  *
   4  * Copyright (c) 2011-2012 Jia Liu <proljc@gmail.com>
   5  *                         Zhizhou Zhang <etouzh@gmail.com>
   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 "cpu.h"
  22 #include "qemu-common.h"
  23 #include "gdbstub.h"
  24 #include "host-utils.h"
  25 #ifndef CONFIG_USER_ONLY
  26 #include "hw/loader.h"
  27 #endif
  28
  29 #ifndef CONFIG_USER_ONLY
  30 int cpu_openrisc_get_phys_nommu(OpenRISCCPU *cpu,
  31                                 hwaddr *physical,
  32                                 int *prot, target_ulong address, int rw)
  33 {
  34     *physical = address;
  35     *prot = PAGE_READ | PAGE_WRITE;
  36     return TLBRET_MATCH;
  37 }
  38
  39 int cpu_openrisc_get_phys_code(OpenRISCCPU *cpu,
  40                                hwaddr *physical,
  41                                int *prot, target_ulong address, int rw)
  42 {
  43     int vpn = address >> TARGET_PAGE_BITS;
  44     int idx = vpn & ITLB_MASK;
  45     int right = 0;
  46
  47     if ((cpu->env.tlb->itlb[0][idx].mr >> TARGET_PAGE_BITS) != vpn) {
  48         return TLBRET_NOMATCH;
  49     }
  50     if (!(cpu->env.tlb->itlb[0][idx].mr & 1)) {
  51         return TLBRET_INVALID;
  52     }
  53
  54     if (cpu->env.sr & SR_SM) { /* supervisor mode */
  55         if (cpu->env.tlb->itlb[0][idx].tr & SXE) {
  56             right |= PAGE_EXEC;
  57         }
  58     } else {
  59         if (cpu->env.tlb->itlb[0][idx].tr & UXE) {
  60             right |= PAGE_EXEC;
  61         }
  62     }
  63
  64     if ((rw & 2) && ((right & PAGE_EXEC) == 0)) {
  65         return TLBRET_BADADDR;
  66     }
  67
  68     *physical = (cpu->env.tlb->itlb[0][idx].tr & TARGET_PAGE_MASK) |
  69                 (address & (TARGET_PAGE_SIZE-1));
  70     *prot = right;
  71     return TLBRET_MATCH;
  72 }
  73
  74 int cpu_openrisc_get_phys_data(OpenRISCCPU *cpu,
  75                                hwaddr *physical,
  76                                int *prot, target_ulong address, int rw)
  77 {
  78     int vpn = address >> TARGET_PAGE_BITS;
  79     int idx = vpn & DTLB_MASK;
  80     int right = 0;
  81
  82     if ((cpu->env.tlb->dtlb[0][idx].mr >> TARGET_PAGE_BITS) != vpn) {
  83         return TLBRET_NOMATCH;
  84     }
  85     if (!(cpu->env.tlb->dtlb[0][idx].mr & 1)) {
  86         return TLBRET_INVALID;
  87     }
  88
  89     if (cpu->env.sr & SR_SM) { /* supervisor mode */
  90         if (cpu->env.tlb->dtlb[0][idx].tr & SRE) {
  91             right |= PAGE_READ;
  92         }
  93         if (cpu->env.tlb->dtlb[0][idx].tr & SWE) {
  94             right |= PAGE_WRITE;
  95         }
  96     } else {
  97         if (cpu->env.tlb->dtlb[0][idx].tr & URE) {
  98             right |= PAGE_READ;
  99         }
 100         if (cpu->env.tlb->dtlb[0][idx].tr & UWE) {
 101             right |= PAGE_WRITE;
 102         }
 103     }
 104
 105     if ((rw & 0) && ((right & PAGE_READ) == 0)) {
 106         return TLBRET_BADADDR;
 107     }
 108     if ((rw & 1) && ((right & PAGE_WRITE) == 0)) {
 109         return TLBRET_BADADDR;
 110     }
 111
 112     *physical = (cpu->env.tlb->dtlb[0][idx].tr & TARGET_PAGE_MASK) |
 113                 (address & (TARGET_PAGE_SIZE-1));
 114     *prot = right;
 115     return TLBRET_MATCH;
 116 }
 117
 118 static int cpu_openrisc_get_phys_addr(OpenRISCCPU *cpu,
 119                                       hwaddr *physical,
 120                                       int *prot, target_ulong address,
 121                                       int rw)
 122 {
 123     int ret = TLBRET_MATCH;
 124
 125     /* [0x0000--0x2000]: unmapped */
 126     if (address < 0x2000 && (cpu->env.sr & SR_SM)) {
 127         *physical = address;
 128         *prot = PAGE_READ | PAGE_WRITE;
 129         return ret;
 130     }
 131
 132     if (rw == 2) {    /* ITLB */
 133        *physical = 0;
 134         ret = cpu->env.tlb->cpu_openrisc_map_address_code(cpu, physical,
 135                                                           prot, address, rw);
 136     } else {          /* DTLB */
 137         ret = cpu->env.tlb->cpu_openrisc_map_address_data(cpu, physical,
 138                                                           prot, address, rw);
 139     }
 140
 141     return ret;
 142 }
 143 #endif
 144
 145 static void cpu_openrisc_raise_mmu_exception(OpenRISCCPU *cpu,
 146                                              target_ulong address,
 147                                              int rw, int tlb_error)
 148 {
 149     int exception = 0;
 150
 151     switch (tlb_error) {
 152     default:
 153         if (rw == 2) {
 154             exception = EXCP_IPF;
 155         } else {
 156             exception = EXCP_DPF;
 157         }
 158         break;
 159 #ifndef CONFIG_USER_ONLY
 160     case TLBRET_BADADDR:
 161         if (rw == 2) {
 162             exception = EXCP_IPF;
 163         } else {
 164             exception = EXCP_DPF;
 165         }
 166         break;
 167     case TLBRET_INVALID:
 168     case TLBRET_NOMATCH:
 169         /* No TLB match for a mapped address */
 170         if (rw == 2) {
 171             exception = EXCP_ITLBMISS;
 172         } else {
 173             exception = EXCP_DTLBMISS;
 174         }
 175         break;
 176 #endif
 177     }
 178
 179     cpu->env.exception_index = exception;
 180     cpu->env.eear = address;
 181 }
 182
 183 #ifndef CONFIG_USER_ONLY
 184 int cpu_openrisc_handle_mmu_fault(CPUOpenRISCState *env,
 185                                   target_ulong address, int rw, int mmu_idx)
 186 {
 187     int ret = 0;
 188     hwaddr physical = 0;
 189     int prot = 0;
 190     OpenRISCCPU *cpu = OPENRISC_CPU(ENV_GET_CPU(env));
 191
 192     ret = cpu_openrisc_get_phys_addr(cpu, &physical, &prot,
 193                                      address, rw);
 194
 195     if (ret == TLBRET_MATCH) {
 196         tlb_set_page(env, address & TARGET_PAGE_MASK,
 197                      physical & TARGET_PAGE_MASK, prot | PAGE_EXEC,
 198                      mmu_idx, TARGET_PAGE_SIZE);
 199         ret = 0;
 200     } else if (ret < 0) {
 201         cpu_openrisc_raise_mmu_exception(cpu, address, rw, ret);
 202         ret = 1;
 203     }
 204
 205     return ret;
 206 }
 207 #else
 208 int cpu_openrisc_handle_mmu_fault(CPUOpenRISCState *env,
 209                                   target_ulong address, int rw, int mmu_idx)
 210 {
 211     int ret = 0;
 212     OpenRISCCPU *cpu = OPENRISC_CPU(ENV_GET_CPU(env));
 213
 214     cpu_openrisc_raise_mmu_exception(cpu, address, rw, ret);
 215     ret = 1;
 216
 217     return ret;
 218 }
 219 #endif
 220
 221 #ifndef CONFIG_USER_ONLY
 222 hwaddr cpu_get_phys_page_debug(CPUOpenRISCState *env,
 223                                            target_ulong addr)
 224 {
 225     hwaddr phys_addr;
 226     int prot;
 227     OpenRISCCPU *cpu = OPENRISC_CPU(ENV_GET_CPU(env));
 228
 229     if (cpu_openrisc_get_phys_addr(cpu, &phys_addr, &prot, addr, 0)) {
 230         return -1;
 231     }
 232
 233     return phys_addr;
 234 }
 235
 236 void cpu_openrisc_mmu_init(OpenRISCCPU *cpu)
 237 {
 238     cpu->env.tlb = g_malloc0(sizeof(CPUOpenRISCTLBContext));
 239
 240     cpu->env.tlb->cpu_openrisc_map_address_code = &cpu_openrisc_get_phys_nommu;
 241     cpu->env.tlb->cpu_openrisc_map_address_data = &cpu_openrisc_get_phys_nommu;
 242 }
 243 #endif