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