cputlb.c

   1 /*
   2  *  Common CPU TLB handling
   3  *
   4  *  Copyright (c) 2003 Fabrice Bellard
   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 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 <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "config.h"
  21 #include "cpu.h"
  22 #include "exec/exec-all.h"
  23 #include "exec/memory.h"
  24 #include "exec/address-spaces.h"
  25
  26 #include "exec/cputlb.h"
  27
  28 #include "exec/memory-internal.h"
  29
  30 //#define DEBUG_TLB
  31 //#define DEBUG_TLB_CHECK
  32
  33 /* statistics */
  34 int tlb_flush_count;
  35
  36 static const CPUTLBEntry s_cputlb_empty_entry = {
  37     .addr_read  = -1,
  38     .addr_write = -1,
  39     .addr_code  = -1,
  40     .addend     = -1,
  41 };
  42
  43 /* NOTE:
  44  * If flush_global is true (the usual case), flush all tlb entries.
  45  * If flush_global is false, flush (at least) all tlb entries not
  46  * marked global.
  47  *
  48  * Since QEMU doesn't currently implement a global/not-global flag
  49  * for tlb entries, at the moment tlb_flush() will also flush all
  50  * tlb entries in the flush_global == false case. This is OK because
  51  * CPU architectures generally permit an implementation to drop
  52  * entries from the TLB at any time, so flushing more entries than
  53  * required is only an efficiency issue, not a correctness issue.
  54  */
  55 void tlb_flush(CPUArchState *env, int flush_global)
  56 {
  57     CPUState *cpu = ENV_GET_CPU(env);
  58     int i;
  59
  60 #if defined(DEBUG_TLB)
  61     printf("tlb_flush:\n");
  62 #endif
  63     /* must reset current TB so that interrupts cannot modify the
  64        links while we are modifying them */
  65     cpu->current_tb = NULL;
  66
  67     for (i = 0; i < CPU_TLB_SIZE; i++) {
  68         int mmu_idx;
  69
  70         for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
  71             env->tlb_table[mmu_idx][i] = s_cputlb_empty_entry;
  72         }
  73     }
  74
  75     memset(env->tb_jmp_cache, 0, TB_JMP_CACHE_SIZE * sizeof (void *));
  76
  77     env->tlb_flush_addr = -1;
  78     env->tlb_flush_mask = 0;
  79     tlb_flush_count++;
  80 }
  81
  82 static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry, target_ulong addr)
  83 {
  84     if (addr == (tlb_entry->addr_read &
  85                  (TARGET_PAGE_MASK | TLB_INVALID_MASK)) ||
  86         addr == (tlb_entry->addr_write &
  87                  (TARGET_PAGE_MASK | TLB_INVALID_MASK)) ||
  88         addr == (tlb_entry->addr_code &
  89                  (TARGET_PAGE_MASK | TLB_INVALID_MASK))) {
  90         *tlb_entry = s_cputlb_empty_entry;
  91     }
  92 }
  93
  94 void tlb_flush_page(CPUArchState *env, target_ulong addr)
  95 {
  96     CPUState *cpu = ENV_GET_CPU(env);
  97     int i;
  98     int mmu_idx;
  99
 100 #if defined(DEBUG_TLB)
 101     printf("tlb_flush_page: " TARGET_FMT_lx "\n", addr);
 102 #endif
 103     /* Check if we need to flush due to large pages.  */
 104     if ((addr & env->tlb_flush_mask) == env->tlb_flush_addr) {
 105 #if defined(DEBUG_TLB)
 106         printf("tlb_flush_page: forced full flush ("
 107                TARGET_FMT_lx "/" TARGET_FMT_lx ")\n",
 108                env->tlb_flush_addr, env->tlb_flush_mask);
 109 #endif
 110         tlb_flush(env, 1);
 111         return;
 112     }
 113     /* must reset current TB so that interrupts cannot modify the
 114        links while we are modifying them */
 115     cpu->current_tb = NULL;
 116
 117     addr &= TARGET_PAGE_MASK;
 118     i = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
 119     for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
 120         tlb_flush_entry(&env->tlb_table[mmu_idx][i], addr);
 121     }
 122
 123     tb_flush_jmp_cache(env, addr);
 124 }
 125
 126 /* update the TLBs so that writes to code in the virtual page 'addr'
 127    can be detected */
 128 void tlb_protect_code(ram_addr_t ram_addr)
 129 {
 130     cpu_physical_memory_reset_dirty(ram_addr,
 131                                     ram_addr + TARGET_PAGE_SIZE,
 132                                     CODE_DIRTY_FLAG);
 133 }
 134
 135 /* update the TLB so that writes in physical page 'phys_addr' are no longer
 136    tested for self modifying code */
 137 void tlb_unprotect_code_phys(CPUArchState *env, ram_addr_t ram_addr,
 138                              target_ulong vaddr)
 139 {
 140     cpu_physical_memory_set_dirty_flags(ram_addr, CODE_DIRTY_FLAG);
 141 }
 142
 143 static bool tlb_is_dirty_ram(CPUTLBEntry *tlbe)
 144 {
 145     return (tlbe->addr_write & (TLB_INVALID_MASK|TLB_MMIO|TLB_NOTDIRTY)) == 0;
 146 }
 147
 148 void tlb_reset_dirty_range(CPUTLBEntry *tlb_entry, uintptr_t start,
 149                            uintptr_t length)
 150 {
 151     uintptr_t addr;
 152
 153     if (tlb_is_dirty_ram(tlb_entry)) {
 154         addr = (tlb_entry->addr_write & TARGET_PAGE_MASK) + tlb_entry->addend;
 155         if ((addr - start) < length) {
 156             tlb_entry->addr_write |= TLB_NOTDIRTY;
 157         }
 158     }
 159 }
 160
 161 static inline void tlb_update_dirty(CPUTLBEntry *tlb_entry)
 162 {
 163     ram_addr_t ram_addr;
 164     void *p;
 165
 166     if (tlb_is_dirty_ram(tlb_entry)) {
 167         p = (void *)(uintptr_t)((tlb_entry->addr_write & TARGET_PAGE_MASK)
 168             + tlb_entry->addend);
 169         ram_addr = qemu_ram_addr_from_host_nofail(p);
 170         if (!cpu_physical_memory_is_dirty(ram_addr)) {
 171             tlb_entry->addr_write |= TLB_NOTDIRTY;
 172         }
 173     }
 174 }
 175
 176 void cpu_tlb_reset_dirty_all(ram_addr_t start1, ram_addr_t length)
 177 {
 178     CPUArchState *env;
 179
 180     for (env = first_cpu; env != NULL; env = env->next_cpu) {
 181         int mmu_idx;
 182
 183         for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
 184             unsigned int i;
 185
 186             for (i = 0; i < CPU_TLB_SIZE; i++) {
 187                 tlb_reset_dirty_range(&env->tlb_table[mmu_idx][i],
 188                                       start1, length);
 189             }
 190         }
 191     }
 192 }
 193
 194 static inline void tlb_set_dirty1(CPUTLBEntry *tlb_entry, target_ulong vaddr)
 195 {
 196     if (tlb_entry->addr_write == (vaddr | TLB_NOTDIRTY)) {
 197         tlb_entry->addr_write = vaddr;
 198     }
 199 }
 200
 201 /* update the TLB corresponding to virtual page vaddr
 202    so that it is no longer dirty */
 203 void tlb_set_dirty(CPUArchState *env, target_ulong vaddr)
 204 {
 205     int i;
 206     int mmu_idx;
 207
 208     vaddr &= TARGET_PAGE_MASK;
 209     i = (vaddr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
 210     for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) {
 211         tlb_set_dirty1(&env->tlb_table[mmu_idx][i], vaddr);
 212     }
 213 }
 214
 215 /* Our TLB does not support large pages, so remember the area covered by
 216    large pages and trigger a full TLB flush if these are invalidated.  */
 217 static void tlb_add_large_page(CPUArchState *env, target_ulong vaddr,
 218                                target_ulong size)
 219 {
 220     target_ulong mask = ~(size - 1);
 221
 222     if (env->tlb_flush_addr == (target_ulong)-1) {
 223         env->tlb_flush_addr = vaddr & mask;
 224         env->tlb_flush_mask = mask;
 225         return;
 226     }
 227     /* Extend the existing region to include the new page.
 228        This is a compromise between unnecessary flushes and the cost
 229        of maintaining a full variable size TLB.  */
 230     mask &= env->tlb_flush_mask;
 231     while (((env->tlb_flush_addr ^ vaddr) & mask) != 0) {
 232         mask <<= 1;
 233     }
 234     env->tlb_flush_addr &= mask;
 235     env->tlb_flush_mask = mask;
 236 }
 237
 238 /* Add a new TLB entry. At most one entry for a given virtual address
 239    is permitted. Only a single TARGET_PAGE_SIZE region is mapped, the
 240    supplied size is only used by tlb_flush_page.  */
 241 void tlb_set_page(CPUArchState *env, target_ulong vaddr,
 242                   hwaddr paddr, int prot,
 243                   int mmu_idx, target_ulong size)
 244 {
 245     MemoryRegionSection *section;
 246     unsigned int index;
 247     target_ulong address;
 248     target_ulong code_address;
 249     uintptr_t addend;
 250     CPUTLBEntry *te;
 251     hwaddr iotlb, xlat, sz;
 252
 253     assert(size >= TARGET_PAGE_SIZE);
 254     if (size != TARGET_PAGE_SIZE) {
 255         tlb_add_large_page(env, vaddr, size);
 256     }
 257
 258     sz = size;
 259     section = address_space_translate_for_iotlb(&address_space_memory, paddr,
 260                                                 &xlat, &sz);
 261     assert(sz >= TARGET_PAGE_SIZE);
 262
 263 #if defined(DEBUG_TLB)
 264     printf("tlb_set_page: vaddr=" TARGET_FMT_lx " paddr=0x" TARGET_FMT_plx
 265            " prot=%x idx=%d\n",
 266            vaddr, paddr, prot, mmu_idx);
 267 #endif
 268
 269     address = vaddr;
 270     if (!memory_region_is_ram(section->mr) && !memory_region_is_romd(section->mr)) {
 271         /* IO memory case */
 272         address |= TLB_MMIO;
 273         addend = 0;
 274     } else {
 275         /* TLB_MMIO for rom/romd handled below */
 276         addend = (uintptr_t)memory_region_get_ram_ptr(section->mr) + xlat;
 277     }
 278
 279     code_address = address;
 280     iotlb = memory_region_section_get_iotlb(env, section, vaddr, paddr, xlat,
 281                                             prot, &address);
 282
 283     index = (vaddr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
 284     env->iotlb[mmu_idx][index] = iotlb - vaddr;
 285     te = &env->tlb_table[mmu_idx][index];
 286     te->addend = addend - vaddr;
 287     if (prot & PAGE_READ) {
 288         te->addr_read = address;
 289     } else {
 290         te->addr_read = -1;
 291     }
 292
 293     if (prot & PAGE_EXEC) {
 294         te->addr_code = code_address;
 295     } else {
 296         te->addr_code = -1;
 297     }
 298     if (prot & PAGE_WRITE) {
 299         if ((memory_region_is_ram(section->mr) && section->readonly)
 300             || memory_region_is_romd(section->mr)) {
 301             /* Write access calls the I/O callback.  */
 302             te->addr_write = address | TLB_MMIO;
 303         } else if (memory_region_is_ram(section->mr)
 304                    && !cpu_physical_memory_is_dirty(section->mr->ram_addr + xlat)) {
 305             te->addr_write = address | TLB_NOTDIRTY;
 306         } else {
 307             te->addr_write = address;
 308         }
 309     } else {
 310         te->addr_write = -1;
 311     }
 312 }
 313
 314 /* NOTE: this function can trigger an exception */
 315 /* NOTE2: the returned address is not exactly the physical address: it
 316  * is actually a ram_addr_t (in system mode; the user mode emulation
 317  * version of this function returns a guest virtual address).
 318  */
 319 tb_page_addr_t get_page_addr_code(CPUArchState *env1, target_ulong addr)
 320 {
 321     int mmu_idx, page_index, pd;
 322     void *p;
 323     MemoryRegion *mr;
 324
 325     page_index = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1);
 326     mmu_idx = cpu_mmu_index(env1);
 327     if (unlikely(env1->tlb_table[mmu_idx][page_index].addr_code !=
 328                  (addr & TARGET_PAGE_MASK))) {
 329         cpu_ldub_code(env1, addr);
 330     }
 331     pd = env1->iotlb[mmu_idx][page_index] & ~TARGET_PAGE_MASK;
 332     mr = iotlb_to_region(pd);
 333     if (memory_region_is_unassigned(mr)) {
 334 #if defined(TARGET_ALPHA) || defined(TARGET_MIPS) || defined(TARGET_SPARC)
 335         cpu_unassigned_access(env1, addr, 0, 1, 0, 4);
 336 #else
 337         cpu_abort(env1, "Trying to execute code outside RAM or ROM at 0x"
 338                   TARGET_FMT_lx "\n", addr);
 339 #endif
 340     }
 341     p = (void *)((uintptr_t)addr + env1->tlb_table[mmu_idx][page_index].addend);
 342     return qemu_ram_addr_from_host_nofail(p);
 343 }
 344
 345 #define MMUSUFFIX _cmmu
 346 #undef GETPC
 347 #define GETPC() ((uintptr_t)0)
 348 #define SOFTMMU_CODE_ACCESS
 349
 350 #define SHIFT 0
 351 #include "exec/softmmu_template.h"
 352
 353 #define SHIFT 1
 354 #include "exec/softmmu_template.h"
 355
 356 #define SHIFT 2
 357 #include "exec/softmmu_template.h"
 358
 359 #define SHIFT 3
 360 #include "exec/softmmu_template.h"
 361
 362 #undef env