kernel/arch/um/kernel/tlb.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <linux/mm.h>
   7 #include <linux/module.h>
   8 #include <linux/sched.h>
   9 #include <asm/pgtable.h>
  10 #include <asm/tlbflush.h>
  11 #include <as-layout.h>
  12 #include <mem_user.h>
  13 #include <os.h>
  14 #include <skas.h>
  15 #include <kern_util.h>
  16
  17 struct host_vm_change {
  18         struct host_vm_op {
  19                 enum { NONE, MMAP, MUNMAP, MPROTECT } type;
  20                 union {
  21                         struct {
  22                                 unsigned long addr;
  23                                 unsigned long len;
  24                                 unsigned int prot;
  25                                 int fd;
  26                                 __u64 offset;
  27                         } mmap;
  28                         struct {
  29                                 unsigned long addr;
  30                                 unsigned long len;
  31                         } munmap;
  32                         struct {
  33                                 unsigned long addr;
  34                                 unsigned long len;
  35                                 unsigned int prot;
  36                         } mprotect;
  37                 } u;
  38         } ops[1];
  39         int index;
  40         struct mm_id *id;
  41         void *data;
  42         int force;
  43 };
  44
  45 #define INIT_HVC(mm, force) \
  46         ((struct host_vm_change) \
  47          { .ops         = { { .type = NONE } }, \
  48            .id          = &mm->context.id, \
  49            .data        = NULL, \
  50            .index       = 0, \
  51            .force       = force })
  52
  53 static int do_ops(struct host_vm_change *hvc, int end,
  54                   int finished)
  55 {
  56         struct host_vm_op *op;
  57         int i, ret = 0;
  58
  59         for (i = 0; i < end && !ret; i++) {
  60                 op = &hvc->ops[i];
  61                 switch (op->type) {
  62                 case MMAP:
  63                         ret = map(hvc->id, op->u.mmap.addr, op->u.mmap.len,
  64                                   op->u.mmap.prot, op->u.mmap.fd,
  65                                   op->u.mmap.offset, finished, &hvc->data);
  66                         break;
  67                 case MUNMAP:
  68                         ret = unmap(hvc->id, op->u.munmap.addr,
  69                                     op->u.munmap.len, finished, &hvc->data);
  70                         break;
  71                 case MPROTECT:
  72                         ret = protect(hvc->id, op->u.mprotect.addr,
  73                                       op->u.mprotect.len, op->u.mprotect.prot,
  74                                       finished, &hvc->data);
  75                         break;
  76                 default:
  77                         printk(KERN_ERR "Unknown op type %d in do_ops\n",
  78                                op->type);
  79                         BUG();
  80                         break;
  81                 }
  82         }
  83
  84         return ret;
  85 }
  86
  87 static int add_mmap(unsigned long virt, unsigned long phys, unsigned long len,
  88                     unsigned int prot, struct host_vm_change *hvc)
  89 {
  90         __u64 offset;
  91         struct host_vm_op *last;
  92         int fd, ret = 0;
  93
  94         fd = phys_mapping(phys, &offset);
  95         if (hvc->index != 0) {
  96                 last = &hvc->ops[hvc->index - 1];
  97                 if ((last->type == MMAP) &&
  98                    (last->u.mmap.addr + last->u.mmap.len == virt) &&
  99                    (last->u.mmap.prot == prot) && (last->u.mmap.fd == fd) &&
 100                    (last->u.mmap.offset + last->u.mmap.len == offset)) {
 101                         last->u.mmap.len += len;
 102                         return 0;
 103                 }
 104         }
 105
 106         if (hvc->index == ARRAY_SIZE(hvc->ops)) {
 107                 ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
 108                 hvc->index = 0;
 109         }
 110
 111         hvc->ops[hvc->index++] = ((struct host_vm_op)
 112                                   { .type       = MMAP,
 113                                     .u = { .mmap = { .addr      = virt,
 114                                                      .len       = len,
 115                                                      .prot      = prot,
 116                                                      .fd        = fd,
 117                                                      .offset    = offset }
 118                            } });
 119         return ret;
 120 }
 121
 122 static int add_munmap(unsigned long addr, unsigned long len,
 123                       struct host_vm_change *hvc)
 124 {
 125         struct host_vm_op *last;
 126         int ret = 0;
 127
 128         if ((addr >= STUB_START) && (addr < STUB_END))
 129                 return -EINVAL;
 130
 131         if (hvc->index != 0) {
 132                 last = &hvc->ops[hvc->index - 1];
 133                 if ((last->type == MUNMAP) &&
 134                    (last->u.munmap.addr + last->u.mmap.len == addr)) {
 135                         last->u.munmap.len += len;
 136                         return 0;
 137                 }
 138         }
 139
 140         if (hvc->index == ARRAY_SIZE(hvc->ops)) {
 141                 ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
 142                 hvc->index = 0;
 143         }
 144
 145         hvc->ops[hvc->index++] = ((struct host_vm_op)
 146                                   { .type       = MUNMAP,
 147                                     .u = { .munmap = { .addr    = addr,
 148                                                        .len     = len } } });
 149         return ret;
 150 }
 151
 152 static int add_mprotect(unsigned long addr, unsigned long len,
 153                         unsigned int prot, struct host_vm_change *hvc)
 154 {
 155         struct host_vm_op *last;
 156         int ret = 0;
 157
 158         if (hvc->index != 0) {
 159                 last = &hvc->ops[hvc->index - 1];
 160                 if ((last->type == MPROTECT) &&
 161                    (last->u.mprotect.addr + last->u.mprotect.len == addr) &&
 162                    (last->u.mprotect.prot == prot)) {
 163                         last->u.mprotect.len += len;
 164                         return 0;
 165                 }
 166         }
 167
 168         if (hvc->index == ARRAY_SIZE(hvc->ops)) {
 169                 ret = do_ops(hvc, ARRAY_SIZE(hvc->ops), 0);
 170                 hvc->index = 0;
 171         }
 172
 173         hvc->ops[hvc->index++] = ((struct host_vm_op)
 174                                   { .type       = MPROTECT,
 175                                     .u = { .mprotect = { .addr  = addr,
 176                                                          .len   = len,
 177                                                          .prot  = prot } } });
 178         return ret;
 179 }
 180
 181 #define ADD_ROUND(n, inc) (((n) + (inc)) & ~((inc) - 1))
 182
 183 static inline int update_pte_range(pmd_t *pmd, unsigned long addr,
 184                                    unsigned long end,
 185                                    struct host_vm_change *hvc)
 186 {
 187         pte_t *pte;
 188         int r, w, x, prot, ret = 0;
 189
 190         pte = pte_offset_kernel(pmd, addr);
 191         do {
 192                 if ((addr >= STUB_START) && (addr < STUB_END))
 193                         continue;
 194
 195                 r = pte_read(*pte);
 196                 w = pte_write(*pte);
 197                 x = pte_exec(*pte);
 198                 if (!pte_young(*pte)) {
 199                         r = 0;
 200                         w = 0;
 201                 } else if (!pte_dirty(*pte))
 202                         w = 0;
 203
 204                 prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
 205                         (x ? UM_PROT_EXEC : 0));
 206                 if (hvc->force || pte_newpage(*pte)) {
 207                         if (pte_present(*pte))
 208                                 ret = add_mmap(addr, pte_val(*pte) & PAGE_MASK,
 209                                                PAGE_SIZE, prot, hvc);
 210                         else
 211                                 ret = add_munmap(addr, PAGE_SIZE, hvc);
 212                 } else if (pte_newprot(*pte))
 213                         ret = add_mprotect(addr, PAGE_SIZE, prot, hvc);
 214                 *pte = pte_mkuptodate(*pte);
 215         } while (pte++, addr += PAGE_SIZE, ((addr < end) && !ret));
 216         return ret;
 217 }
 218
 219 static inline int update_pmd_range(pud_t *pud, unsigned long addr,
 220                                    unsigned long end,
 221                                    struct host_vm_change *hvc)
 222 {
 223         pmd_t *pmd;
 224         unsigned long next;
 225         int ret = 0;
 226
 227         pmd = pmd_offset(pud, addr);
 228         do {
 229                 next = pmd_addr_end(addr, end);
 230                 if (!pmd_present(*pmd)) {
 231                         if (hvc->force || pmd_newpage(*pmd)) {
 232                                 ret = add_munmap(addr, next - addr, hvc);
 233                                 pmd_mkuptodate(*pmd);
 234                         }
 235                 }
 236                 else ret = update_pte_range(pmd, addr, next, hvc);
 237         } while (pmd++, addr = next, ((addr < end) && !ret));
 238         return ret;
 239 }
 240
 241 static inline int update_pud_range(pgd_t *pgd, unsigned long addr,
 242                                    unsigned long end,
 243                                    struct host_vm_change *hvc)
 244 {
 245         pud_t *pud;
 246         unsigned long next;
 247         int ret = 0;
 248
 249         pud = pud_offset(pgd, addr);
 250         do {
 251                 next = pud_addr_end(addr, end);
 252                 if (!pud_present(*pud)) {
 253                         if (hvc->force || pud_newpage(*pud)) {
 254                                 ret = add_munmap(addr, next - addr, hvc);
 255                                 pud_mkuptodate(*pud);
 256                         }
 257                 }
 258                 else ret = update_pmd_range(pud, addr, next, hvc);
 259         } while (pud++, addr = next, ((addr < end) && !ret));
 260         return ret;
 261 }
 262
 263 void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
 264                       unsigned long end_addr, int force)
 265 {
 266         pgd_t *pgd;
 267         struct host_vm_change hvc;
 268         unsigned long addr = start_addr, next;
 269         int ret = 0;
 270
 271         hvc = INIT_HVC(mm, force);
 272         pgd = pgd_offset(mm, addr);
 273         do {
 274                 next = pgd_addr_end(addr, end_addr);
 275                 if (!pgd_present(*pgd)) {
 276                         if (force || pgd_newpage(*pgd)) {
 277                                 ret = add_munmap(addr, next - addr, &hvc);
 278                                 pgd_mkuptodate(*pgd);
 279                         }
 280                 }
 281                 else ret = update_pud_range(pgd, addr, next, &hvc);
 282         } while (pgd++, addr = next, ((addr < end_addr) && !ret));
 283
 284         if (!ret)
 285                 ret = do_ops(&hvc, hvc.index, 1);
 286
 287         /* This is not an else because ret is modified above */
 288         if (ret) {
 289                 printk(KERN_ERR "fix_range_common: failed, killing current "
 290                        "process: %d\n", task_tgid_vnr(current));
 291                 /* We are under mmap_sem, release it such that current can terminate */
 292                 up_write(&current->mm->mmap_sem);
 293                 force_sig(SIGKILL, current);
 294                 do_signal();
 295         }
 296 }
 297
 298 static int flush_tlb_kernel_range_common(unsigned long start, unsigned long end)
 299 {
 300         struct mm_struct *mm;
 301         pgd_t *pgd;
 302         pud_t *pud;
 303         pmd_t *pmd;
 304         pte_t *pte;
 305         unsigned long addr, last;
 306         int updated = 0, err;
 307
 308         mm = &init_mm;
 309         for (addr = start; addr < end;) {
 310                 pgd = pgd_offset(mm, addr);
 311                 if (!pgd_present(*pgd)) {
 312                         last = ADD_ROUND(addr, PGDIR_SIZE);
 313                         if (last > end)
 314                                 last = end;
 315                         if (pgd_newpage(*pgd)) {
 316                                 updated = 1;
 317                                 err = os_unmap_memory((void *) addr,
 318                                                       last - addr);
 319                                 if (err < 0)
 320                                         panic("munmap failed, errno = %d\n",
 321                                               -err);
 322                         }
 323                         addr = last;
 324                         continue;
 325                 }
 326
 327                 pud = pud_offset(pgd, addr);
 328                 if (!pud_present(*pud)) {
 329                         last = ADD_ROUND(addr, PUD_SIZE);
 330                         if (last > end)
 331                                 last = end;
 332                         if (pud_newpage(*pud)) {
 333                                 updated = 1;
 334                                 err = os_unmap_memory((void *) addr,
 335                                                       last - addr);
 336                                 if (err < 0)
 337                                         panic("munmap failed, errno = %d\n",
 338                                               -err);
 339                         }
 340                         addr = last;
 341                         continue;
 342                 }
 343
 344                 pmd = pmd_offset(pud, addr);
 345                 if (!pmd_present(*pmd)) {
 346                         last = ADD_ROUND(addr, PMD_SIZE);
 347                         if (last > end)
 348                                 last = end;
 349                         if (pmd_newpage(*pmd)) {
 350                                 updated = 1;
 351                                 err = os_unmap_memory((void *) addr,
 352                                                       last - addr);
 353                                 if (err < 0)
 354                                         panic("munmap failed, errno = %d\n",
 355                                               -err);
 356                         }
 357                         addr = last;
 358                         continue;
 359                 }
 360
 361                 pte = pte_offset_kernel(pmd, addr);
 362                 if (!pte_present(*pte) || pte_newpage(*pte)) {
 363                         updated = 1;
 364                         err = os_unmap_memory((void *) addr,
 365                                               PAGE_SIZE);
 366                         if (err < 0)
 367                                 panic("munmap failed, errno = %d\n",
 368                                       -err);
 369                         if (pte_present(*pte))
 370                                 map_memory(addr,
 371                                            pte_val(*pte) & PAGE_MASK,
 372                                            PAGE_SIZE, 1, 1, 1);
 373                 }
 374                 else if (pte_newprot(*pte)) {
 375                         updated = 1;
 376                         os_protect_memory((void *) addr, PAGE_SIZE, 1, 1, 1);
 377                 }
 378                 addr += PAGE_SIZE;
 379         }
 380         return updated;
 381 }
 382
 383 void flush_tlb_page(struct vm_area_struct *vma, unsigned long address)
 384 {
 385         pgd_t *pgd;
 386         pud_t *pud;
 387         pmd_t *pmd;
 388         pte_t *pte;
 389         struct mm_struct *mm = vma->vm_mm;
 390         void *flush = NULL;
 391         int r, w, x, prot, err = 0;
 392         struct mm_id *mm_id;
 393
 394         address &= PAGE_MASK;
 395         pgd = pgd_offset(mm, address);
 396         if (!pgd_present(*pgd))
 397                 goto kill;
 398
 399         pud = pud_offset(pgd, address);
 400         if (!pud_present(*pud))
 401                 goto kill;
 402
 403         pmd = pmd_offset(pud, address);
 404         if (!pmd_present(*pmd))
 405                 goto kill;
 406
 407         pte = pte_offset_kernel(pmd, address);
 408
 409         r = pte_read(*pte);
 410         w = pte_write(*pte);
 411         x = pte_exec(*pte);
 412         if (!pte_young(*pte)) {
 413                 r = 0;
 414                 w = 0;
 415         } else if (!pte_dirty(*pte)) {
 416                 w = 0;
 417         }
 418
 419         mm_id = &mm->context.id;
 420         prot = ((r ? UM_PROT_READ : 0) | (w ? UM_PROT_WRITE : 0) |
 421                 (x ? UM_PROT_EXEC : 0));
 422         if (pte_newpage(*pte)) {
 423                 if (pte_present(*pte)) {
 424                         unsigned long long offset;
 425                         int fd;
 426
 427                         fd = phys_mapping(pte_val(*pte) & PAGE_MASK, &offset);
 428                         err = map(mm_id, address, PAGE_SIZE, prot, fd, offset,
 429                                   1, &flush);
 430                 }
 431                 else err = unmap(mm_id, address, PAGE_SIZE, 1, &flush);
 432         }
 433         else if (pte_newprot(*pte))
 434                 err = protect(mm_id, address, PAGE_SIZE, prot, 1, &flush);
 435
 436         if (err)
 437                 goto kill;
 438
 439         *pte = pte_mkuptodate(*pte);
 440
 441         return;
 442
 443 kill:
 444         printk(KERN_ERR "Failed to flush page for address 0x%lx\n", address);
 445         force_sig(SIGKILL, current);
 446 }
 447
 448 pgd_t *pgd_offset_proc(struct mm_struct *mm, unsigned long address)
 449 {
 450         return pgd_offset(mm, address);
 451 }
 452
 453 pud_t *pud_offset_proc(pgd_t *pgd, unsigned long address)
 454 {
 455         return pud_offset(pgd, address);
 456 }
 457
 458 pmd_t *pmd_offset_proc(pud_t *pud, unsigned long address)
 459 {
 460         return pmd_offset(pud, address);
 461 }
 462
 463 pte_t *pte_offset_proc(pmd_t *pmd, unsigned long address)
 464 {
 465         return pte_offset_kernel(pmd, address);
 466 }
 467
 468 pte_t *addr_pte(struct task_struct *task, unsigned long addr)
 469 {
 470         pgd_t *pgd = pgd_offset(task->mm, addr);
 471         pud_t *pud = pud_offset(pgd, addr);
 472         pmd_t *pmd = pmd_offset(pud, addr);
 473
 474         return pte_offset_map(pmd, addr);
 475 }
 476
 477 void flush_tlb_all(void)
 478 {
 479         flush_tlb_mm(current->mm);
 480 }
 481
 482 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
 483 {
 484         flush_tlb_kernel_range_common(start, end);
 485 }
 486
 487 void flush_tlb_kernel_vm(void)
 488 {
 489         flush_tlb_kernel_range_common(start_vm, end_vm);
 490 }
 491
 492 void __flush_tlb_one(unsigned long addr)
 493 {
 494         flush_tlb_kernel_range_common(addr, addr + PAGE_SIZE);
 495 }
 496
 497 static void fix_range(struct mm_struct *mm, unsigned long start_addr,
 498                       unsigned long end_addr, int force)
 499 {
 500         fix_range_common(mm, start_addr, end_addr, force);
 501 }
 502
 503 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 504                      unsigned long end)
 505 {
 506         if (vma->vm_mm == NULL)
 507                 flush_tlb_kernel_range_common(start, end);
 508         else fix_range(vma->vm_mm, start, end, 0);
 509 }
 510 EXPORT_SYMBOL(flush_tlb_range);
 511
 512 void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
 513                         unsigned long end)
 514 {
 515         /*
 516          * Don't bother flushing if this address space is about to be
 517          * destroyed.
 518          */
 519         if (atomic_read(&mm->mm_users) == 0)
 520                 return;
 521
 522         fix_range(mm, start, end, 0);
 523 }
 524
 525 void flush_tlb_mm(struct mm_struct *mm)
 526 {
 527         struct vm_area_struct *vma = mm->mmap;
 528
 529         while (vma != NULL) {
 530                 fix_range(mm, vma->vm_start, vma->vm_end, 0);
 531                 vma = vma->vm_next;
 532         }
 533 }
 534
 535 void force_flush_all(void)
 536 {
 537         struct mm_struct *mm = current->mm;
 538         struct vm_area_struct *vma = mm->mmap;
 539
 540         while (vma != NULL) {
 541                 fix_range(mm, vma->vm_start, vma->vm_end, 1);
 542                 vma = vma->vm_next;
 543         }
 544 }