| 1 | /* |
| 2 | * linux/mm/nommu.c |
| 3 | * |
| 4 | * Replacement code for mm functions to support CPU's that don't |
| 5 | * have any form of memory management unit (thus no virtual memory). |
| 6 | * |
| 7 | * See Documentation/nommu-mmap.txt |
| 8 | * |
| 9 | * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com> |
| 10 | * Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com> |
| 11 | * Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org> |
| 12 | * Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com> |
| 13 | * Copyright (c) 2007-2010 Paul Mundt <lethal@linux-sh.org> |
| 14 | */ |
| 15 | |
| 16 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 17 | |
| 18 | #include <linux/export.h> |
| 19 | #include <linux/mm.h> |
| 20 | #include <linux/vmacache.h> |
| 21 | #include <linux/mman.h> |
| 22 | #include <linux/swap.h> |
| 23 | #include <linux/file.h> |
| 24 | #include <linux/highmem.h> |
| 25 | #include <linux/pagemap.h> |
| 26 | #include <linux/slab.h> |
| 27 | #include <linux/vmalloc.h> |
| 28 | #include <linux/blkdev.h> |
| 29 | #include <linux/backing-dev.h> |
| 30 | #include <linux/compiler.h> |
| 31 | #include <linux/mount.h> |
| 32 | #include <linux/personality.h> |
| 33 | #include <linux/security.h> |
| 34 | #include <linux/syscalls.h> |
| 35 | #include <linux/audit.h> |
| 36 | #include <linux/printk.h> |
| 37 | |
| 38 | #include <asm/uaccess.h> |
| 39 | #include <asm/tlb.h> |
| 40 | #include <asm/tlbflush.h> |
| 41 | #include <asm/mmu_context.h> |
| 42 | #include "internal.h" |
| 43 | |
| 44 | void *high_memory; |
| 45 | EXPORT_SYMBOL(high_memory); |
| 46 | struct page *mem_map; |
| 47 | unsigned long max_mapnr; |
| 48 | EXPORT_SYMBOL(max_mapnr); |
| 49 | unsigned long highest_memmap_pfn; |
| 50 | int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS; |
| 51 | int heap_stack_gap = 0; |
| 52 | |
| 53 | atomic_long_t mmap_pages_allocated; |
| 54 | |
| 55 | EXPORT_SYMBOL(mem_map); |
| 56 | |
| 57 | /* list of mapped, potentially shareable regions */ |
| 58 | static struct kmem_cache *vm_region_jar; |
| 59 | struct rb_root nommu_region_tree = RB_ROOT; |
| 60 | DECLARE_RWSEM(nommu_region_sem); |
| 61 | |
| 62 | const struct vm_operations_struct generic_file_vm_ops = { |
| 63 | }; |
| 64 | |
| 65 | /* |
| 66 | * Return the total memory allocated for this pointer, not |
| 67 | * just what the caller asked for. |
| 68 | * |
| 69 | * Doesn't have to be accurate, i.e. may have races. |
| 70 | */ |
| 71 | unsigned int kobjsize(const void *objp) |
| 72 | { |
| 73 | struct page *page; |
| 74 | |
| 75 | /* |
| 76 | * If the object we have should not have ksize performed on it, |
| 77 | * return size of 0 |
| 78 | */ |
| 79 | if (!objp || !virt_addr_valid(objp)) |
| 80 | return 0; |
| 81 | |
| 82 | page = virt_to_head_page(objp); |
| 83 | |
| 84 | /* |
| 85 | * If the allocator sets PageSlab, we know the pointer came from |
| 86 | * kmalloc(). |
| 87 | */ |
| 88 | if (PageSlab(page)) |
| 89 | return ksize(objp); |
| 90 | |
| 91 | /* |
| 92 | * If it's not a compound page, see if we have a matching VMA |
| 93 | * region. This test is intentionally done in reverse order, |
| 94 | * so if there's no VMA, we still fall through and hand back |
| 95 | * PAGE_SIZE for 0-order pages. |
| 96 | */ |
| 97 | if (!PageCompound(page)) { |
| 98 | struct vm_area_struct *vma; |
| 99 | |
| 100 | vma = find_vma(current->mm, (unsigned long)objp); |
| 101 | if (vma) |
| 102 | return vma->vm_end - vma->vm_start; |
| 103 | } |
| 104 | |
| 105 | /* |
| 106 | * The ksize() function is only guaranteed to work for pointers |
| 107 | * returned by kmalloc(). So handle arbitrary pointers here. |
| 108 | */ |
| 109 | return PAGE_SIZE << compound_order(page); |
| 110 | } |
| 111 | |
| 112 | long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
| 113 | unsigned long start, unsigned long nr_pages, |
| 114 | unsigned int foll_flags, struct page **pages, |
| 115 | struct vm_area_struct **vmas, int *nonblocking) |
| 116 | { |
| 117 | struct vm_area_struct *vma; |
| 118 | unsigned long vm_flags; |
| 119 | int i; |
| 120 | |
| 121 | /* calculate required read or write permissions. |
| 122 | * If FOLL_FORCE is set, we only require the "MAY" flags. |
| 123 | */ |
| 124 | vm_flags = (foll_flags & FOLL_WRITE) ? |
| 125 | (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
| 126 | vm_flags &= (foll_flags & FOLL_FORCE) ? |
| 127 | (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); |
| 128 | |
| 129 | for (i = 0; i < nr_pages; i++) { |
| 130 | vma = find_vma(mm, start); |
| 131 | if (!vma) |
| 132 | goto finish_or_fault; |
| 133 | |
| 134 | /* protect what we can, including chardevs */ |
| 135 | if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) || |
| 136 | !(vm_flags & vma->vm_flags)) |
| 137 | goto finish_or_fault; |
| 138 | |
| 139 | if (pages) { |
| 140 | pages[i] = virt_to_page(start); |
| 141 | if (pages[i]) |
| 142 | get_page(pages[i]); |
| 143 | } |
| 144 | if (vmas) |
| 145 | vmas[i] = vma; |
| 146 | start = (start + PAGE_SIZE) & PAGE_MASK; |
| 147 | } |
| 148 | |
| 149 | return i; |
| 150 | |
| 151 | finish_or_fault: |
| 152 | return i ? : -EFAULT; |
| 153 | } |
| 154 | |
| 155 | /* |
| 156 | * get a list of pages in an address range belonging to the specified process |
| 157 | * and indicate the VMA that covers each page |
| 158 | * - this is potentially dodgy as we may end incrementing the page count of a |
| 159 | * slab page or a secondary page from a compound page |
| 160 | * - don't permit access to VMAs that don't support it, such as I/O mappings |
| 161 | */ |
| 162 | long get_user_pages(unsigned long start, unsigned long nr_pages, |
| 163 | int write, int force, struct page **pages, |
| 164 | struct vm_area_struct **vmas) |
| 165 | { |
| 166 | int flags = 0; |
| 167 | |
| 168 | if (write) |
| 169 | flags |= FOLL_WRITE; |
| 170 | if (force) |
| 171 | flags |= FOLL_FORCE; |
| 172 | |
| 173 | return __get_user_pages(current, current->mm, start, nr_pages, flags, |
| 174 | pages, vmas, NULL); |
| 175 | } |
| 176 | EXPORT_SYMBOL(get_user_pages); |
| 177 | |
| 178 | long get_user_pages_locked(unsigned long start, unsigned long nr_pages, |
| 179 | int write, int force, struct page **pages, |
| 180 | int *locked) |
| 181 | { |
| 182 | return get_user_pages(start, nr_pages, write, force, pages, NULL); |
| 183 | } |
| 184 | EXPORT_SYMBOL(get_user_pages_locked); |
| 185 | |
| 186 | long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, |
| 187 | unsigned long start, unsigned long nr_pages, |
| 188 | int write, int force, struct page **pages, |
| 189 | unsigned int gup_flags) |
| 190 | { |
| 191 | long ret; |
| 192 | down_read(&mm->mmap_sem); |
| 193 | ret = __get_user_pages(tsk, mm, start, nr_pages, gup_flags, pages, |
| 194 | NULL, NULL); |
| 195 | up_read(&mm->mmap_sem); |
| 196 | return ret; |
| 197 | } |
| 198 | EXPORT_SYMBOL(__get_user_pages_unlocked); |
| 199 | |
| 200 | long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, |
| 201 | int write, int force, struct page **pages) |
| 202 | { |
| 203 | return __get_user_pages_unlocked(current, current->mm, start, nr_pages, |
| 204 | write, force, pages, 0); |
| 205 | } |
| 206 | EXPORT_SYMBOL(get_user_pages_unlocked); |
| 207 | |
| 208 | /** |
| 209 | * follow_pfn - look up PFN at a user virtual address |
| 210 | * @vma: memory mapping |
| 211 | * @address: user virtual address |
| 212 | * @pfn: location to store found PFN |
| 213 | * |
| 214 | * Only IO mappings and raw PFN mappings are allowed. |
| 215 | * |
| 216 | * Returns zero and the pfn at @pfn on success, -ve otherwise. |
| 217 | */ |
| 218 | int follow_pfn(struct vm_area_struct *vma, unsigned long address, |
| 219 | unsigned long *pfn) |
| 220 | { |
| 221 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) |
| 222 | return -EINVAL; |
| 223 | |
| 224 | *pfn = address >> PAGE_SHIFT; |
| 225 | return 0; |
| 226 | } |
| 227 | EXPORT_SYMBOL(follow_pfn); |
| 228 | |
| 229 | LIST_HEAD(vmap_area_list); |
| 230 | |
| 231 | void vfree(const void *addr) |
| 232 | { |
| 233 | kfree(addr); |
| 234 | } |
| 235 | EXPORT_SYMBOL(vfree); |
| 236 | |
| 237 | void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) |
| 238 | { |
| 239 | /* |
| 240 | * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc() |
| 241 | * returns only a logical address. |
| 242 | */ |
| 243 | return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); |
| 244 | } |
| 245 | EXPORT_SYMBOL(__vmalloc); |
| 246 | |
| 247 | void *vmalloc_user(unsigned long size) |
| 248 | { |
| 249 | void *ret; |
| 250 | |
| 251 | ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, |
| 252 | PAGE_KERNEL); |
| 253 | if (ret) { |
| 254 | struct vm_area_struct *vma; |
| 255 | |
| 256 | down_write(¤t->mm->mmap_sem); |
| 257 | vma = find_vma(current->mm, (unsigned long)ret); |
| 258 | if (vma) |
| 259 | vma->vm_flags |= VM_USERMAP; |
| 260 | up_write(¤t->mm->mmap_sem); |
| 261 | } |
| 262 | |
| 263 | return ret; |
| 264 | } |
| 265 | EXPORT_SYMBOL(vmalloc_user); |
| 266 | |
| 267 | struct page *vmalloc_to_page(const void *addr) |
| 268 | { |
| 269 | return virt_to_page(addr); |
| 270 | } |
| 271 | EXPORT_SYMBOL(vmalloc_to_page); |
| 272 | |
| 273 | unsigned long vmalloc_to_pfn(const void *addr) |
| 274 | { |
| 275 | return page_to_pfn(virt_to_page(addr)); |
| 276 | } |
| 277 | EXPORT_SYMBOL(vmalloc_to_pfn); |
| 278 | |
| 279 | long vread(char *buf, char *addr, unsigned long count) |
| 280 | { |
| 281 | /* Don't allow overflow */ |
| 282 | if ((unsigned long) buf + count < count) |
| 283 | count = -(unsigned long) buf; |
| 284 | |
| 285 | memcpy(buf, addr, count); |
| 286 | return count; |
| 287 | } |
| 288 | |
| 289 | long vwrite(char *buf, char *addr, unsigned long count) |
| 290 | { |
| 291 | /* Don't allow overflow */ |
| 292 | if ((unsigned long) addr + count < count) |
| 293 | count = -(unsigned long) addr; |
| 294 | |
| 295 | memcpy(addr, buf, count); |
| 296 | return count; |
| 297 | } |
| 298 | |
| 299 | /* |
| 300 | * vmalloc - allocate virtually contiguous memory |
| 301 | * |
| 302 | * @size: allocation size |
| 303 | * |
| 304 | * Allocate enough pages to cover @size from the page level |
| 305 | * allocator and map them into contiguous kernel virtual space. |
| 306 | * |
| 307 | * For tight control over page level allocator and protection flags |
| 308 | * use __vmalloc() instead. |
| 309 | */ |
| 310 | void *vmalloc(unsigned long size) |
| 311 | { |
| 312 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); |
| 313 | } |
| 314 | EXPORT_SYMBOL(vmalloc); |
| 315 | |
| 316 | /* |
| 317 | * vzalloc - allocate virtually contiguous memory with zero fill |
| 318 | * |
| 319 | * @size: allocation size |
| 320 | * |
| 321 | * Allocate enough pages to cover @size from the page level |
| 322 | * allocator and map them into contiguous kernel virtual space. |
| 323 | * The memory allocated is set to zero. |
| 324 | * |
| 325 | * For tight control over page level allocator and protection flags |
| 326 | * use __vmalloc() instead. |
| 327 | */ |
| 328 | void *vzalloc(unsigned long size) |
| 329 | { |
| 330 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, |
| 331 | PAGE_KERNEL); |
| 332 | } |
| 333 | EXPORT_SYMBOL(vzalloc); |
| 334 | |
| 335 | /** |
| 336 | * vmalloc_node - allocate memory on a specific node |
| 337 | * @size: allocation size |
| 338 | * @node: numa node |
| 339 | * |
| 340 | * Allocate enough pages to cover @size from the page level |
| 341 | * allocator and map them into contiguous kernel virtual space. |
| 342 | * |
| 343 | * For tight control over page level allocator and protection flags |
| 344 | * use __vmalloc() instead. |
| 345 | */ |
| 346 | void *vmalloc_node(unsigned long size, int node) |
| 347 | { |
| 348 | return vmalloc(size); |
| 349 | } |
| 350 | EXPORT_SYMBOL(vmalloc_node); |
| 351 | |
| 352 | /** |
| 353 | * vzalloc_node - allocate memory on a specific node with zero fill |
| 354 | * @size: allocation size |
| 355 | * @node: numa node |
| 356 | * |
| 357 | * Allocate enough pages to cover @size from the page level |
| 358 | * allocator and map them into contiguous kernel virtual space. |
| 359 | * The memory allocated is set to zero. |
| 360 | * |
| 361 | * For tight control over page level allocator and protection flags |
| 362 | * use __vmalloc() instead. |
| 363 | */ |
| 364 | void *vzalloc_node(unsigned long size, int node) |
| 365 | { |
| 366 | return vzalloc(size); |
| 367 | } |
| 368 | EXPORT_SYMBOL(vzalloc_node); |
| 369 | |
| 370 | #ifndef PAGE_KERNEL_EXEC |
| 371 | # define PAGE_KERNEL_EXEC PAGE_KERNEL |
| 372 | #endif |
| 373 | |
| 374 | /** |
| 375 | * vmalloc_exec - allocate virtually contiguous, executable memory |
| 376 | * @size: allocation size |
| 377 | * |
| 378 | * Kernel-internal function to allocate enough pages to cover @size |
| 379 | * the page level allocator and map them into contiguous and |
| 380 | * executable kernel virtual space. |
| 381 | * |
| 382 | * For tight control over page level allocator and protection flags |
| 383 | * use __vmalloc() instead. |
| 384 | */ |
| 385 | |
| 386 | void *vmalloc_exec(unsigned long size) |
| 387 | { |
| 388 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC); |
| 389 | } |
| 390 | |
| 391 | /** |
| 392 | * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) |
| 393 | * @size: allocation size |
| 394 | * |
| 395 | * Allocate enough 32bit PA addressable pages to cover @size from the |
| 396 | * page level allocator and map them into contiguous kernel virtual space. |
| 397 | */ |
| 398 | void *vmalloc_32(unsigned long size) |
| 399 | { |
| 400 | return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); |
| 401 | } |
| 402 | EXPORT_SYMBOL(vmalloc_32); |
| 403 | |
| 404 | /** |
| 405 | * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory |
| 406 | * @size: allocation size |
| 407 | * |
| 408 | * The resulting memory area is 32bit addressable and zeroed so it can be |
| 409 | * mapped to userspace without leaking data. |
| 410 | * |
| 411 | * VM_USERMAP is set on the corresponding VMA so that subsequent calls to |
| 412 | * remap_vmalloc_range() are permissible. |
| 413 | */ |
| 414 | void *vmalloc_32_user(unsigned long size) |
| 415 | { |
| 416 | /* |
| 417 | * We'll have to sort out the ZONE_DMA bits for 64-bit, |
| 418 | * but for now this can simply use vmalloc_user() directly. |
| 419 | */ |
| 420 | return vmalloc_user(size); |
| 421 | } |
| 422 | EXPORT_SYMBOL(vmalloc_32_user); |
| 423 | |
| 424 | void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) |
| 425 | { |
| 426 | BUG(); |
| 427 | return NULL; |
| 428 | } |
| 429 | EXPORT_SYMBOL(vmap); |
| 430 | |
| 431 | void vunmap(const void *addr) |
| 432 | { |
| 433 | BUG(); |
| 434 | } |
| 435 | EXPORT_SYMBOL(vunmap); |
| 436 | |
| 437 | void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot) |
| 438 | { |
| 439 | BUG(); |
| 440 | return NULL; |
| 441 | } |
| 442 | EXPORT_SYMBOL(vm_map_ram); |
| 443 | |
| 444 | void vm_unmap_ram(const void *mem, unsigned int count) |
| 445 | { |
| 446 | BUG(); |
| 447 | } |
| 448 | EXPORT_SYMBOL(vm_unmap_ram); |
| 449 | |
| 450 | void vm_unmap_aliases(void) |
| 451 | { |
| 452 | } |
| 453 | EXPORT_SYMBOL_GPL(vm_unmap_aliases); |
| 454 | |
| 455 | /* |
| 456 | * Implement a stub for vmalloc_sync_all() if the architecture chose not to |
| 457 | * have one. |
| 458 | */ |
| 459 | void __weak vmalloc_sync_all(void) |
| 460 | { |
| 461 | } |
| 462 | |
| 463 | /** |
| 464 | * alloc_vm_area - allocate a range of kernel address space |
| 465 | * @size: size of the area |
| 466 | * |
| 467 | * Returns: NULL on failure, vm_struct on success |
| 468 | * |
| 469 | * This function reserves a range of kernel address space, and |
| 470 | * allocates pagetables to map that range. No actual mappings |
| 471 | * are created. If the kernel address space is not shared |
| 472 | * between processes, it syncs the pagetable across all |
| 473 | * processes. |
| 474 | */ |
| 475 | struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes) |
| 476 | { |
| 477 | BUG(); |
| 478 | return NULL; |
| 479 | } |
| 480 | EXPORT_SYMBOL_GPL(alloc_vm_area); |
| 481 | |
| 482 | void free_vm_area(struct vm_struct *area) |
| 483 | { |
| 484 | BUG(); |
| 485 | } |
| 486 | EXPORT_SYMBOL_GPL(free_vm_area); |
| 487 | |
| 488 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
| 489 | struct page *page) |
| 490 | { |
| 491 | return -EINVAL; |
| 492 | } |
| 493 | EXPORT_SYMBOL(vm_insert_page); |
| 494 | |
| 495 | /* |
| 496 | * sys_brk() for the most part doesn't need the global kernel |
| 497 | * lock, except when an application is doing something nasty |
| 498 | * like trying to un-brk an area that has already been mapped |
| 499 | * to a regular file. in this case, the unmapping will need |
| 500 | * to invoke file system routines that need the global lock. |
| 501 | */ |
| 502 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
| 503 | { |
| 504 | struct mm_struct *mm = current->mm; |
| 505 | |
| 506 | if (brk < mm->start_brk || brk > mm->context.end_brk) |
| 507 | return mm->brk; |
| 508 | |
| 509 | if (mm->brk == brk) |
| 510 | return mm->brk; |
| 511 | |
| 512 | /* |
| 513 | * Always allow shrinking brk |
| 514 | */ |
| 515 | if (brk <= mm->brk) { |
| 516 | mm->brk = brk; |
| 517 | return brk; |
| 518 | } |
| 519 | |
| 520 | /* |
| 521 | * Ok, looks good - let it rip. |
| 522 | */ |
| 523 | flush_icache_range(mm->brk, brk); |
| 524 | return mm->brk = brk; |
| 525 | } |
| 526 | |
| 527 | /* |
| 528 | * initialise the VMA and region record slabs |
| 529 | */ |
| 530 | void __init mmap_init(void) |
| 531 | { |
| 532 | int ret; |
| 533 | |
| 534 | ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); |
| 535 | VM_BUG_ON(ret); |
| 536 | vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT); |
| 537 | } |
| 538 | |
| 539 | /* |
| 540 | * validate the region tree |
| 541 | * - the caller must hold the region lock |
| 542 | */ |
| 543 | #ifdef CONFIG_DEBUG_NOMMU_REGIONS |
| 544 | static noinline void validate_nommu_regions(void) |
| 545 | { |
| 546 | struct vm_region *region, *last; |
| 547 | struct rb_node *p, *lastp; |
| 548 | |
| 549 | lastp = rb_first(&nommu_region_tree); |
| 550 | if (!lastp) |
| 551 | return; |
| 552 | |
| 553 | last = rb_entry(lastp, struct vm_region, vm_rb); |
| 554 | BUG_ON(last->vm_end <= last->vm_start); |
| 555 | BUG_ON(last->vm_top < last->vm_end); |
| 556 | |
| 557 | while ((p = rb_next(lastp))) { |
| 558 | region = rb_entry(p, struct vm_region, vm_rb); |
| 559 | last = rb_entry(lastp, struct vm_region, vm_rb); |
| 560 | |
| 561 | BUG_ON(region->vm_end <= region->vm_start); |
| 562 | BUG_ON(region->vm_top < region->vm_end); |
| 563 | BUG_ON(region->vm_start < last->vm_top); |
| 564 | |
| 565 | lastp = p; |
| 566 | } |
| 567 | } |
| 568 | #else |
| 569 | static void validate_nommu_regions(void) |
| 570 | { |
| 571 | } |
| 572 | #endif |
| 573 | |
| 574 | /* |
| 575 | * add a region into the global tree |
| 576 | */ |
| 577 | static void add_nommu_region(struct vm_region *region) |
| 578 | { |
| 579 | struct vm_region *pregion; |
| 580 | struct rb_node **p, *parent; |
| 581 | |
| 582 | validate_nommu_regions(); |
| 583 | |
| 584 | parent = NULL; |
| 585 | p = &nommu_region_tree.rb_node; |
| 586 | while (*p) { |
| 587 | parent = *p; |
| 588 | pregion = rb_entry(parent, struct vm_region, vm_rb); |
| 589 | if (region->vm_start < pregion->vm_start) |
| 590 | p = &(*p)->rb_left; |
| 591 | else if (region->vm_start > pregion->vm_start) |
| 592 | p = &(*p)->rb_right; |
| 593 | else if (pregion == region) |
| 594 | return; |
| 595 | else |
| 596 | BUG(); |
| 597 | } |
| 598 | |
| 599 | rb_link_node(®ion->vm_rb, parent, p); |
| 600 | rb_insert_color(®ion->vm_rb, &nommu_region_tree); |
| 601 | |
| 602 | validate_nommu_regions(); |
| 603 | } |
| 604 | |
| 605 | /* |
| 606 | * delete a region from the global tree |
| 607 | */ |
| 608 | static void delete_nommu_region(struct vm_region *region) |
| 609 | { |
| 610 | BUG_ON(!nommu_region_tree.rb_node); |
| 611 | |
| 612 | validate_nommu_regions(); |
| 613 | rb_erase(®ion->vm_rb, &nommu_region_tree); |
| 614 | validate_nommu_regions(); |
| 615 | } |
| 616 | |
| 617 | /* |
| 618 | * free a contiguous series of pages |
| 619 | */ |
| 620 | static void free_page_series(unsigned long from, unsigned long to) |
| 621 | { |
| 622 | for (; from < to; from += PAGE_SIZE) { |
| 623 | struct page *page = virt_to_page(from); |
| 624 | |
| 625 | atomic_long_dec(&mmap_pages_allocated); |
| 626 | put_page(page); |
| 627 | } |
| 628 | } |
| 629 | |
| 630 | /* |
| 631 | * release a reference to a region |
| 632 | * - the caller must hold the region semaphore for writing, which this releases |
| 633 | * - the region may not have been added to the tree yet, in which case vm_top |
| 634 | * will equal vm_start |
| 635 | */ |
| 636 | static void __put_nommu_region(struct vm_region *region) |
| 637 | __releases(nommu_region_sem) |
| 638 | { |
| 639 | BUG_ON(!nommu_region_tree.rb_node); |
| 640 | |
| 641 | if (--region->vm_usage == 0) { |
| 642 | if (region->vm_top > region->vm_start) |
| 643 | delete_nommu_region(region); |
| 644 | up_write(&nommu_region_sem); |
| 645 | |
| 646 | if (region->vm_file) |
| 647 | fput(region->vm_file); |
| 648 | |
| 649 | /* IO memory and memory shared directly out of the pagecache |
| 650 | * from ramfs/tmpfs mustn't be released here */ |
| 651 | if (region->vm_flags & VM_MAPPED_COPY) |
| 652 | free_page_series(region->vm_start, region->vm_top); |
| 653 | kmem_cache_free(vm_region_jar, region); |
| 654 | } else { |
| 655 | up_write(&nommu_region_sem); |
| 656 | } |
| 657 | } |
| 658 | |
| 659 | /* |
| 660 | * release a reference to a region |
| 661 | */ |
| 662 | static void put_nommu_region(struct vm_region *region) |
| 663 | { |
| 664 | down_write(&nommu_region_sem); |
| 665 | __put_nommu_region(region); |
| 666 | } |
| 667 | |
| 668 | /* |
| 669 | * update protection on a vma |
| 670 | */ |
| 671 | static void protect_vma(struct vm_area_struct *vma, unsigned long flags) |
| 672 | { |
| 673 | #ifdef CONFIG_MPU |
| 674 | struct mm_struct *mm = vma->vm_mm; |
| 675 | long start = vma->vm_start & PAGE_MASK; |
| 676 | while (start < vma->vm_end) { |
| 677 | protect_page(mm, start, flags); |
| 678 | start += PAGE_SIZE; |
| 679 | } |
| 680 | update_protections(mm); |
| 681 | #endif |
| 682 | } |
| 683 | |
| 684 | /* |
| 685 | * add a VMA into a process's mm_struct in the appropriate place in the list |
| 686 | * and tree and add to the address space's page tree also if not an anonymous |
| 687 | * page |
| 688 | * - should be called with mm->mmap_sem held writelocked |
| 689 | */ |
| 690 | static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) |
| 691 | { |
| 692 | struct vm_area_struct *pvma, *prev; |
| 693 | struct address_space *mapping; |
| 694 | struct rb_node **p, *parent, *rb_prev; |
| 695 | |
| 696 | BUG_ON(!vma->vm_region); |
| 697 | |
| 698 | mm->map_count++; |
| 699 | vma->vm_mm = mm; |
| 700 | |
| 701 | protect_vma(vma, vma->vm_flags); |
| 702 | |
| 703 | /* add the VMA to the mapping */ |
| 704 | if (vma->vm_file) { |
| 705 | mapping = vma->vm_file->f_mapping; |
| 706 | |
| 707 | i_mmap_lock_write(mapping); |
| 708 | flush_dcache_mmap_lock(mapping); |
| 709 | vma_interval_tree_insert(vma, &mapping->i_mmap); |
| 710 | flush_dcache_mmap_unlock(mapping); |
| 711 | i_mmap_unlock_write(mapping); |
| 712 | } |
| 713 | |
| 714 | /* add the VMA to the tree */ |
| 715 | parent = rb_prev = NULL; |
| 716 | p = &mm->mm_rb.rb_node; |
| 717 | while (*p) { |
| 718 | parent = *p; |
| 719 | pvma = rb_entry(parent, struct vm_area_struct, vm_rb); |
| 720 | |
| 721 | /* sort by: start addr, end addr, VMA struct addr in that order |
| 722 | * (the latter is necessary as we may get identical VMAs) */ |
| 723 | if (vma->vm_start < pvma->vm_start) |
| 724 | p = &(*p)->rb_left; |
| 725 | else if (vma->vm_start > pvma->vm_start) { |
| 726 | rb_prev = parent; |
| 727 | p = &(*p)->rb_right; |
| 728 | } else if (vma->vm_end < pvma->vm_end) |
| 729 | p = &(*p)->rb_left; |
| 730 | else if (vma->vm_end > pvma->vm_end) { |
| 731 | rb_prev = parent; |
| 732 | p = &(*p)->rb_right; |
| 733 | } else if (vma < pvma) |
| 734 | p = &(*p)->rb_left; |
| 735 | else if (vma > pvma) { |
| 736 | rb_prev = parent; |
| 737 | p = &(*p)->rb_right; |
| 738 | } else |
| 739 | BUG(); |
| 740 | } |
| 741 | |
| 742 | rb_link_node(&vma->vm_rb, parent, p); |
| 743 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); |
| 744 | |
| 745 | /* add VMA to the VMA list also */ |
| 746 | prev = NULL; |
| 747 | if (rb_prev) |
| 748 | prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); |
| 749 | |
| 750 | __vma_link_list(mm, vma, prev, parent); |
| 751 | } |
| 752 | |
| 753 | /* |
| 754 | * delete a VMA from its owning mm_struct and address space |
| 755 | */ |
| 756 | static void delete_vma_from_mm(struct vm_area_struct *vma) |
| 757 | { |
| 758 | int i; |
| 759 | struct address_space *mapping; |
| 760 | struct mm_struct *mm = vma->vm_mm; |
| 761 | struct task_struct *curr = current; |
| 762 | |
| 763 | protect_vma(vma, 0); |
| 764 | |
| 765 | mm->map_count--; |
| 766 | for (i = 0; i < VMACACHE_SIZE; i++) { |
| 767 | /* if the vma is cached, invalidate the entire cache */ |
| 768 | if (curr->vmacache[i] == vma) { |
| 769 | vmacache_invalidate(mm); |
| 770 | break; |
| 771 | } |
| 772 | } |
| 773 | |
| 774 | /* remove the VMA from the mapping */ |
| 775 | if (vma->vm_file) { |
| 776 | mapping = vma->vm_file->f_mapping; |
| 777 | |
| 778 | i_mmap_lock_write(mapping); |
| 779 | flush_dcache_mmap_lock(mapping); |
| 780 | vma_interval_tree_remove(vma, &mapping->i_mmap); |
| 781 | flush_dcache_mmap_unlock(mapping); |
| 782 | i_mmap_unlock_write(mapping); |
| 783 | } |
| 784 | |
| 785 | /* remove from the MM's tree and list */ |
| 786 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
| 787 | |
| 788 | if (vma->vm_prev) |
| 789 | vma->vm_prev->vm_next = vma->vm_next; |
| 790 | else |
| 791 | mm->mmap = vma->vm_next; |
| 792 | |
| 793 | if (vma->vm_next) |
| 794 | vma->vm_next->vm_prev = vma->vm_prev; |
| 795 | } |
| 796 | |
| 797 | /* |
| 798 | * destroy a VMA record |
| 799 | */ |
| 800 | static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) |
| 801 | { |
| 802 | if (vma->vm_ops && vma->vm_ops->close) |
| 803 | vma->vm_ops->close(vma); |
| 804 | if (vma->vm_file) |
| 805 | fput(vma->vm_file); |
| 806 | put_nommu_region(vma->vm_region); |
| 807 | kmem_cache_free(vm_area_cachep, vma); |
| 808 | } |
| 809 | |
| 810 | /* |
| 811 | * look up the first VMA in which addr resides, NULL if none |
| 812 | * - should be called with mm->mmap_sem at least held readlocked |
| 813 | */ |
| 814 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
| 815 | { |
| 816 | struct vm_area_struct *vma; |
| 817 | |
| 818 | /* check the cache first */ |
| 819 | vma = vmacache_find(mm, addr); |
| 820 | if (likely(vma)) |
| 821 | return vma; |
| 822 | |
| 823 | /* trawl the list (there may be multiple mappings in which addr |
| 824 | * resides) */ |
| 825 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
| 826 | if (vma->vm_start > addr) |
| 827 | return NULL; |
| 828 | if (vma->vm_end > addr) { |
| 829 | vmacache_update(addr, vma); |
| 830 | return vma; |
| 831 | } |
| 832 | } |
| 833 | |
| 834 | return NULL; |
| 835 | } |
| 836 | EXPORT_SYMBOL(find_vma); |
| 837 | |
| 838 | /* |
| 839 | * find a VMA |
| 840 | * - we don't extend stack VMAs under NOMMU conditions |
| 841 | */ |
| 842 | struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) |
| 843 | { |
| 844 | return find_vma(mm, addr); |
| 845 | } |
| 846 | |
| 847 | /* |
| 848 | * expand a stack to a given address |
| 849 | * - not supported under NOMMU conditions |
| 850 | */ |
| 851 | int expand_stack(struct vm_area_struct *vma, unsigned long address) |
| 852 | { |
| 853 | return -ENOMEM; |
| 854 | } |
| 855 | |
| 856 | /* |
| 857 | * look up the first VMA exactly that exactly matches addr |
| 858 | * - should be called with mm->mmap_sem at least held readlocked |
| 859 | */ |
| 860 | static struct vm_area_struct *find_vma_exact(struct mm_struct *mm, |
| 861 | unsigned long addr, |
| 862 | unsigned long len) |
| 863 | { |
| 864 | struct vm_area_struct *vma; |
| 865 | unsigned long end = addr + len; |
| 866 | |
| 867 | /* check the cache first */ |
| 868 | vma = vmacache_find_exact(mm, addr, end); |
| 869 | if (vma) |
| 870 | return vma; |
| 871 | |
| 872 | /* trawl the list (there may be multiple mappings in which addr |
| 873 | * resides) */ |
| 874 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
| 875 | if (vma->vm_start < addr) |
| 876 | continue; |
| 877 | if (vma->vm_start > addr) |
| 878 | return NULL; |
| 879 | if (vma->vm_end == end) { |
| 880 | vmacache_update(addr, vma); |
| 881 | return vma; |
| 882 | } |
| 883 | } |
| 884 | |
| 885 | return NULL; |
| 886 | } |
| 887 | |
| 888 | /* |
| 889 | * determine whether a mapping should be permitted and, if so, what sort of |
| 890 | * mapping we're capable of supporting |
| 891 | */ |
| 892 | static int validate_mmap_request(struct file *file, |
| 893 | unsigned long addr, |
| 894 | unsigned long len, |
| 895 | unsigned long prot, |
| 896 | unsigned long flags, |
| 897 | unsigned long pgoff, |
| 898 | unsigned long *_capabilities) |
| 899 | { |
| 900 | unsigned long capabilities, rlen; |
| 901 | int ret; |
| 902 | |
| 903 | /* do the simple checks first */ |
| 904 | if (flags & MAP_FIXED) |
| 905 | return -EINVAL; |
| 906 | |
| 907 | if ((flags & MAP_TYPE) != MAP_PRIVATE && |
| 908 | (flags & MAP_TYPE) != MAP_SHARED) |
| 909 | return -EINVAL; |
| 910 | |
| 911 | if (!len) |
| 912 | return -EINVAL; |
| 913 | |
| 914 | /* Careful about overflows.. */ |
| 915 | rlen = PAGE_ALIGN(len); |
| 916 | if (!rlen || rlen > TASK_SIZE) |
| 917 | return -ENOMEM; |
| 918 | |
| 919 | /* offset overflow? */ |
| 920 | if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff) |
| 921 | return -EOVERFLOW; |
| 922 | |
| 923 | if (file) { |
| 924 | /* files must support mmap */ |
| 925 | if (!file->f_op->mmap) |
| 926 | return -ENODEV; |
| 927 | |
| 928 | /* work out if what we've got could possibly be shared |
| 929 | * - we support chardevs that provide their own "memory" |
| 930 | * - we support files/blockdevs that are memory backed |
| 931 | */ |
| 932 | if (file->f_op->mmap_capabilities) { |
| 933 | capabilities = file->f_op->mmap_capabilities(file); |
| 934 | } else { |
| 935 | /* no explicit capabilities set, so assume some |
| 936 | * defaults */ |
| 937 | switch (file_inode(file)->i_mode & S_IFMT) { |
| 938 | case S_IFREG: |
| 939 | case S_IFBLK: |
| 940 | capabilities = NOMMU_MAP_COPY; |
| 941 | break; |
| 942 | |
| 943 | case S_IFCHR: |
| 944 | capabilities = |
| 945 | NOMMU_MAP_DIRECT | |
| 946 | NOMMU_MAP_READ | |
| 947 | NOMMU_MAP_WRITE; |
| 948 | break; |
| 949 | |
| 950 | default: |
| 951 | return -EINVAL; |
| 952 | } |
| 953 | } |
| 954 | |
| 955 | /* eliminate any capabilities that we can't support on this |
| 956 | * device */ |
| 957 | if (!file->f_op->get_unmapped_area) |
| 958 | capabilities &= ~NOMMU_MAP_DIRECT; |
| 959 | if (!(file->f_mode & FMODE_CAN_READ)) |
| 960 | capabilities &= ~NOMMU_MAP_COPY; |
| 961 | |
| 962 | /* The file shall have been opened with read permission. */ |
| 963 | if (!(file->f_mode & FMODE_READ)) |
| 964 | return -EACCES; |
| 965 | |
| 966 | if (flags & MAP_SHARED) { |
| 967 | /* do checks for writing, appending and locking */ |
| 968 | if ((prot & PROT_WRITE) && |
| 969 | !(file->f_mode & FMODE_WRITE)) |
| 970 | return -EACCES; |
| 971 | |
| 972 | if (IS_APPEND(file_inode(file)) && |
| 973 | (file->f_mode & FMODE_WRITE)) |
| 974 | return -EACCES; |
| 975 | |
| 976 | if (locks_verify_locked(file)) |
| 977 | return -EAGAIN; |
| 978 | |
| 979 | if (!(capabilities & NOMMU_MAP_DIRECT)) |
| 980 | return -ENODEV; |
| 981 | |
| 982 | /* we mustn't privatise shared mappings */ |
| 983 | capabilities &= ~NOMMU_MAP_COPY; |
| 984 | } else { |
| 985 | /* we're going to read the file into private memory we |
| 986 | * allocate */ |
| 987 | if (!(capabilities & NOMMU_MAP_COPY)) |
| 988 | return -ENODEV; |
| 989 | |
| 990 | /* we don't permit a private writable mapping to be |
| 991 | * shared with the backing device */ |
| 992 | if (prot & PROT_WRITE) |
| 993 | capabilities &= ~NOMMU_MAP_DIRECT; |
| 994 | } |
| 995 | |
| 996 | if (capabilities & NOMMU_MAP_DIRECT) { |
| 997 | if (((prot & PROT_READ) && !(capabilities & NOMMU_MAP_READ)) || |
| 998 | ((prot & PROT_WRITE) && !(capabilities & NOMMU_MAP_WRITE)) || |
| 999 | ((prot & PROT_EXEC) && !(capabilities & NOMMU_MAP_EXEC)) |
| 1000 | ) { |
| 1001 | capabilities &= ~NOMMU_MAP_DIRECT; |
| 1002 | if (flags & MAP_SHARED) { |
| 1003 | pr_warn("MAP_SHARED not completely supported on !MMU\n"); |
| 1004 | return -EINVAL; |
| 1005 | } |
| 1006 | } |
| 1007 | } |
| 1008 | |
| 1009 | /* handle executable mappings and implied executable |
| 1010 | * mappings */ |
| 1011 | if (path_noexec(&file->f_path)) { |
| 1012 | if (prot & PROT_EXEC) |
| 1013 | return -EPERM; |
| 1014 | } else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { |
| 1015 | /* handle implication of PROT_EXEC by PROT_READ */ |
| 1016 | if (current->personality & READ_IMPLIES_EXEC) { |
| 1017 | if (capabilities & NOMMU_MAP_EXEC) |
| 1018 | prot |= PROT_EXEC; |
| 1019 | } |
| 1020 | } else if ((prot & PROT_READ) && |
| 1021 | (prot & PROT_EXEC) && |
| 1022 | !(capabilities & NOMMU_MAP_EXEC) |
| 1023 | ) { |
| 1024 | /* backing file is not executable, try to copy */ |
| 1025 | capabilities &= ~NOMMU_MAP_DIRECT; |
| 1026 | } |
| 1027 | } else { |
| 1028 | /* anonymous mappings are always memory backed and can be |
| 1029 | * privately mapped |
| 1030 | */ |
| 1031 | capabilities = NOMMU_MAP_COPY; |
| 1032 | |
| 1033 | /* handle PROT_EXEC implication by PROT_READ */ |
| 1034 | if ((prot & PROT_READ) && |
| 1035 | (current->personality & READ_IMPLIES_EXEC)) |
| 1036 | prot |= PROT_EXEC; |
| 1037 | } |
| 1038 | |
| 1039 | /* allow the security API to have its say */ |
| 1040 | ret = security_mmap_addr(addr); |
| 1041 | if (ret < 0) |
| 1042 | return ret; |
| 1043 | |
| 1044 | /* looks okay */ |
| 1045 | *_capabilities = capabilities; |
| 1046 | return 0; |
| 1047 | } |
| 1048 | |
| 1049 | /* |
| 1050 | * we've determined that we can make the mapping, now translate what we |
| 1051 | * now know into VMA flags |
| 1052 | */ |
| 1053 | static unsigned long determine_vm_flags(struct file *file, |
| 1054 | unsigned long prot, |
| 1055 | unsigned long flags, |
| 1056 | unsigned long capabilities) |
| 1057 | { |
| 1058 | unsigned long vm_flags; |
| 1059 | |
| 1060 | vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags); |
| 1061 | /* vm_flags |= mm->def_flags; */ |
| 1062 | |
| 1063 | if (!(capabilities & NOMMU_MAP_DIRECT)) { |
| 1064 | /* attempt to share read-only copies of mapped file chunks */ |
| 1065 | vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
| 1066 | if (file && !(prot & PROT_WRITE)) |
| 1067 | vm_flags |= VM_MAYSHARE; |
| 1068 | } else { |
| 1069 | /* overlay a shareable mapping on the backing device or inode |
| 1070 | * if possible - used for chardevs, ramfs/tmpfs/shmfs and |
| 1071 | * romfs/cramfs */ |
| 1072 | vm_flags |= VM_MAYSHARE | (capabilities & NOMMU_VMFLAGS); |
| 1073 | if (flags & MAP_SHARED) |
| 1074 | vm_flags |= VM_SHARED; |
| 1075 | } |
| 1076 | |
| 1077 | /* refuse to let anyone share private mappings with this process if |
| 1078 | * it's being traced - otherwise breakpoints set in it may interfere |
| 1079 | * with another untraced process |
| 1080 | */ |
| 1081 | if ((flags & MAP_PRIVATE) && current->ptrace) |
| 1082 | vm_flags &= ~VM_MAYSHARE; |
| 1083 | |
| 1084 | return vm_flags; |
| 1085 | } |
| 1086 | |
| 1087 | /* |
| 1088 | * set up a shared mapping on a file (the driver or filesystem provides and |
| 1089 | * pins the storage) |
| 1090 | */ |
| 1091 | static int do_mmap_shared_file(struct vm_area_struct *vma) |
| 1092 | { |
| 1093 | int ret; |
| 1094 | |
| 1095 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
| 1096 | if (ret == 0) { |
| 1097 | vma->vm_region->vm_top = vma->vm_region->vm_end; |
| 1098 | return 0; |
| 1099 | } |
| 1100 | if (ret != -ENOSYS) |
| 1101 | return ret; |
| 1102 | |
| 1103 | /* getting -ENOSYS indicates that direct mmap isn't possible (as |
| 1104 | * opposed to tried but failed) so we can only give a suitable error as |
| 1105 | * it's not possible to make a private copy if MAP_SHARED was given */ |
| 1106 | return -ENODEV; |
| 1107 | } |
| 1108 | |
| 1109 | /* |
| 1110 | * set up a private mapping or an anonymous shared mapping |
| 1111 | */ |
| 1112 | static int do_mmap_private(struct vm_area_struct *vma, |
| 1113 | struct vm_region *region, |
| 1114 | unsigned long len, |
| 1115 | unsigned long capabilities) |
| 1116 | { |
| 1117 | unsigned long total, point; |
| 1118 | void *base; |
| 1119 | int ret, order; |
| 1120 | |
| 1121 | /* invoke the file's mapping function so that it can keep track of |
| 1122 | * shared mappings on devices or memory |
| 1123 | * - VM_MAYSHARE will be set if it may attempt to share |
| 1124 | */ |
| 1125 | if (capabilities & NOMMU_MAP_DIRECT) { |
| 1126 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
| 1127 | if (ret == 0) { |
| 1128 | /* shouldn't return success if we're not sharing */ |
| 1129 | BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); |
| 1130 | vma->vm_region->vm_top = vma->vm_region->vm_end; |
| 1131 | return 0; |
| 1132 | } |
| 1133 | if (ret != -ENOSYS) |
| 1134 | return ret; |
| 1135 | |
| 1136 | /* getting an ENOSYS error indicates that direct mmap isn't |
| 1137 | * possible (as opposed to tried but failed) so we'll try to |
| 1138 | * make a private copy of the data and map that instead */ |
| 1139 | } |
| 1140 | |
| 1141 | |
| 1142 | /* allocate some memory to hold the mapping |
| 1143 | * - note that this may not return a page-aligned address if the object |
| 1144 | * we're allocating is smaller than a page |
| 1145 | */ |
| 1146 | order = get_order(len); |
| 1147 | total = 1 << order; |
| 1148 | point = len >> PAGE_SHIFT; |
| 1149 | |
| 1150 | /* we don't want to allocate a power-of-2 sized page set */ |
| 1151 | if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) |
| 1152 | total = point; |
| 1153 | |
| 1154 | base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL); |
| 1155 | if (!base) |
| 1156 | goto enomem; |
| 1157 | |
| 1158 | atomic_long_add(total, &mmap_pages_allocated); |
| 1159 | |
| 1160 | region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; |
| 1161 | region->vm_start = (unsigned long) base; |
| 1162 | region->vm_end = region->vm_start + len; |
| 1163 | region->vm_top = region->vm_start + (total << PAGE_SHIFT); |
| 1164 | |
| 1165 | vma->vm_start = region->vm_start; |
| 1166 | vma->vm_end = region->vm_start + len; |
| 1167 | |
| 1168 | if (vma->vm_file) { |
| 1169 | /* read the contents of a file into the copy */ |
| 1170 | mm_segment_t old_fs; |
| 1171 | loff_t fpos; |
| 1172 | |
| 1173 | fpos = vma->vm_pgoff; |
| 1174 | fpos <<= PAGE_SHIFT; |
| 1175 | |
| 1176 | old_fs = get_fs(); |
| 1177 | set_fs(KERNEL_DS); |
| 1178 | ret = __vfs_read(vma->vm_file, base, len, &fpos); |
| 1179 | set_fs(old_fs); |
| 1180 | |
| 1181 | if (ret < 0) |
| 1182 | goto error_free; |
| 1183 | |
| 1184 | /* clear the last little bit */ |
| 1185 | if (ret < len) |
| 1186 | memset(base + ret, 0, len - ret); |
| 1187 | |
| 1188 | } |
| 1189 | |
| 1190 | return 0; |
| 1191 | |
| 1192 | error_free: |
| 1193 | free_page_series(region->vm_start, region->vm_top); |
| 1194 | region->vm_start = vma->vm_start = 0; |
| 1195 | region->vm_end = vma->vm_end = 0; |
| 1196 | region->vm_top = 0; |
| 1197 | return ret; |
| 1198 | |
| 1199 | enomem: |
| 1200 | pr_err("Allocation of length %lu from process %d (%s) failed\n", |
| 1201 | len, current->pid, current->comm); |
| 1202 | show_free_areas(0); |
| 1203 | return -ENOMEM; |
| 1204 | } |
| 1205 | |
| 1206 | /* |
| 1207 | * handle mapping creation for uClinux |
| 1208 | */ |
| 1209 | unsigned long do_mmap(struct file *file, |
| 1210 | unsigned long addr, |
| 1211 | unsigned long len, |
| 1212 | unsigned long prot, |
| 1213 | unsigned long flags, |
| 1214 | vm_flags_t vm_flags, |
| 1215 | unsigned long pgoff, |
| 1216 | unsigned long *populate) |
| 1217 | { |
| 1218 | struct vm_area_struct *vma; |
| 1219 | struct vm_region *region; |
| 1220 | struct rb_node *rb; |
| 1221 | unsigned long capabilities, result; |
| 1222 | int ret; |
| 1223 | |
| 1224 | *populate = 0; |
| 1225 | |
| 1226 | /* decide whether we should attempt the mapping, and if so what sort of |
| 1227 | * mapping */ |
| 1228 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, |
| 1229 | &capabilities); |
| 1230 | if (ret < 0) |
| 1231 | return ret; |
| 1232 | |
| 1233 | /* we ignore the address hint */ |
| 1234 | addr = 0; |
| 1235 | len = PAGE_ALIGN(len); |
| 1236 | |
| 1237 | /* we've determined that we can make the mapping, now translate what we |
| 1238 | * now know into VMA flags */ |
| 1239 | vm_flags |= determine_vm_flags(file, prot, flags, capabilities); |
| 1240 | |
| 1241 | /* we're going to need to record the mapping */ |
| 1242 | region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL); |
| 1243 | if (!region) |
| 1244 | goto error_getting_region; |
| 1245 | |
| 1246 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
| 1247 | if (!vma) |
| 1248 | goto error_getting_vma; |
| 1249 | |
| 1250 | region->vm_usage = 1; |
| 1251 | region->vm_flags = vm_flags; |
| 1252 | region->vm_pgoff = pgoff; |
| 1253 | |
| 1254 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
| 1255 | vma->vm_flags = vm_flags; |
| 1256 | vma->vm_pgoff = pgoff; |
| 1257 | |
| 1258 | if (file) { |
| 1259 | region->vm_file = get_file(file); |
| 1260 | vma->vm_file = get_file(file); |
| 1261 | } |
| 1262 | |
| 1263 | down_write(&nommu_region_sem); |
| 1264 | |
| 1265 | /* if we want to share, we need to check for regions created by other |
| 1266 | * mmap() calls that overlap with our proposed mapping |
| 1267 | * - we can only share with a superset match on most regular files |
| 1268 | * - shared mappings on character devices and memory backed files are |
| 1269 | * permitted to overlap inexactly as far as we are concerned for in |
| 1270 | * these cases, sharing is handled in the driver or filesystem rather |
| 1271 | * than here |
| 1272 | */ |
| 1273 | if (vm_flags & VM_MAYSHARE) { |
| 1274 | struct vm_region *pregion; |
| 1275 | unsigned long pglen, rpglen, pgend, rpgend, start; |
| 1276 | |
| 1277 | pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1278 | pgend = pgoff + pglen; |
| 1279 | |
| 1280 | for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) { |
| 1281 | pregion = rb_entry(rb, struct vm_region, vm_rb); |
| 1282 | |
| 1283 | if (!(pregion->vm_flags & VM_MAYSHARE)) |
| 1284 | continue; |
| 1285 | |
| 1286 | /* search for overlapping mappings on the same file */ |
| 1287 | if (file_inode(pregion->vm_file) != |
| 1288 | file_inode(file)) |
| 1289 | continue; |
| 1290 | |
| 1291 | if (pregion->vm_pgoff >= pgend) |
| 1292 | continue; |
| 1293 | |
| 1294 | rpglen = pregion->vm_end - pregion->vm_start; |
| 1295 | rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1296 | rpgend = pregion->vm_pgoff + rpglen; |
| 1297 | if (pgoff >= rpgend) |
| 1298 | continue; |
| 1299 | |
| 1300 | /* handle inexactly overlapping matches between |
| 1301 | * mappings */ |
| 1302 | if ((pregion->vm_pgoff != pgoff || rpglen != pglen) && |
| 1303 | !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) { |
| 1304 | /* new mapping is not a subset of the region */ |
| 1305 | if (!(capabilities & NOMMU_MAP_DIRECT)) |
| 1306 | goto sharing_violation; |
| 1307 | continue; |
| 1308 | } |
| 1309 | |
| 1310 | /* we've found a region we can share */ |
| 1311 | pregion->vm_usage++; |
| 1312 | vma->vm_region = pregion; |
| 1313 | start = pregion->vm_start; |
| 1314 | start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT; |
| 1315 | vma->vm_start = start; |
| 1316 | vma->vm_end = start + len; |
| 1317 | |
| 1318 | if (pregion->vm_flags & VM_MAPPED_COPY) |
| 1319 | vma->vm_flags |= VM_MAPPED_COPY; |
| 1320 | else { |
| 1321 | ret = do_mmap_shared_file(vma); |
| 1322 | if (ret < 0) { |
| 1323 | vma->vm_region = NULL; |
| 1324 | vma->vm_start = 0; |
| 1325 | vma->vm_end = 0; |
| 1326 | pregion->vm_usage--; |
| 1327 | pregion = NULL; |
| 1328 | goto error_just_free; |
| 1329 | } |
| 1330 | } |
| 1331 | fput(region->vm_file); |
| 1332 | kmem_cache_free(vm_region_jar, region); |
| 1333 | region = pregion; |
| 1334 | result = start; |
| 1335 | goto share; |
| 1336 | } |
| 1337 | |
| 1338 | /* obtain the address at which to make a shared mapping |
| 1339 | * - this is the hook for quasi-memory character devices to |
| 1340 | * tell us the location of a shared mapping |
| 1341 | */ |
| 1342 | if (capabilities & NOMMU_MAP_DIRECT) { |
| 1343 | addr = file->f_op->get_unmapped_area(file, addr, len, |
| 1344 | pgoff, flags); |
| 1345 | if (IS_ERR_VALUE(addr)) { |
| 1346 | ret = addr; |
| 1347 | if (ret != -ENOSYS) |
| 1348 | goto error_just_free; |
| 1349 | |
| 1350 | /* the driver refused to tell us where to site |
| 1351 | * the mapping so we'll have to attempt to copy |
| 1352 | * it */ |
| 1353 | ret = -ENODEV; |
| 1354 | if (!(capabilities & NOMMU_MAP_COPY)) |
| 1355 | goto error_just_free; |
| 1356 | |
| 1357 | capabilities &= ~NOMMU_MAP_DIRECT; |
| 1358 | } else { |
| 1359 | vma->vm_start = region->vm_start = addr; |
| 1360 | vma->vm_end = region->vm_end = addr + len; |
| 1361 | } |
| 1362 | } |
| 1363 | } |
| 1364 | |
| 1365 | vma->vm_region = region; |
| 1366 | |
| 1367 | /* set up the mapping |
| 1368 | * - the region is filled in if NOMMU_MAP_DIRECT is still set |
| 1369 | */ |
| 1370 | if (file && vma->vm_flags & VM_SHARED) |
| 1371 | ret = do_mmap_shared_file(vma); |
| 1372 | else |
| 1373 | ret = do_mmap_private(vma, region, len, capabilities); |
| 1374 | if (ret < 0) |
| 1375 | goto error_just_free; |
| 1376 | add_nommu_region(region); |
| 1377 | |
| 1378 | /* clear anonymous mappings that don't ask for uninitialized data */ |
| 1379 | if (!vma->vm_file && !(flags & MAP_UNINITIALIZED)) |
| 1380 | memset((void *)region->vm_start, 0, |
| 1381 | region->vm_end - region->vm_start); |
| 1382 | |
| 1383 | /* okay... we have a mapping; now we have to register it */ |
| 1384 | result = vma->vm_start; |
| 1385 | |
| 1386 | current->mm->total_vm += len >> PAGE_SHIFT; |
| 1387 | |
| 1388 | share: |
| 1389 | add_vma_to_mm(current->mm, vma); |
| 1390 | |
| 1391 | /* we flush the region from the icache only when the first executable |
| 1392 | * mapping of it is made */ |
| 1393 | if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) { |
| 1394 | flush_icache_range(region->vm_start, region->vm_end); |
| 1395 | region->vm_icache_flushed = true; |
| 1396 | } |
| 1397 | |
| 1398 | up_write(&nommu_region_sem); |
| 1399 | |
| 1400 | return result; |
| 1401 | |
| 1402 | error_just_free: |
| 1403 | up_write(&nommu_region_sem); |
| 1404 | error: |
| 1405 | if (region->vm_file) |
| 1406 | fput(region->vm_file); |
| 1407 | kmem_cache_free(vm_region_jar, region); |
| 1408 | if (vma->vm_file) |
| 1409 | fput(vma->vm_file); |
| 1410 | kmem_cache_free(vm_area_cachep, vma); |
| 1411 | return ret; |
| 1412 | |
| 1413 | sharing_violation: |
| 1414 | up_write(&nommu_region_sem); |
| 1415 | pr_warn("Attempt to share mismatched mappings\n"); |
| 1416 | ret = -EINVAL; |
| 1417 | goto error; |
| 1418 | |
| 1419 | error_getting_vma: |
| 1420 | kmem_cache_free(vm_region_jar, region); |
| 1421 | pr_warn("Allocation of vma for %lu byte allocation from process %d failed\n", |
| 1422 | len, current->pid); |
| 1423 | show_free_areas(0); |
| 1424 | return -ENOMEM; |
| 1425 | |
| 1426 | error_getting_region: |
| 1427 | pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n", |
| 1428 | len, current->pid); |
| 1429 | show_free_areas(0); |
| 1430 | return -ENOMEM; |
| 1431 | } |
| 1432 | |
| 1433 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
| 1434 | unsigned long, prot, unsigned long, flags, |
| 1435 | unsigned long, fd, unsigned long, pgoff) |
| 1436 | { |
| 1437 | struct file *file = NULL; |
| 1438 | unsigned long retval = -EBADF; |
| 1439 | |
| 1440 | audit_mmap_fd(fd, flags); |
| 1441 | if (!(flags & MAP_ANONYMOUS)) { |
| 1442 | file = fget(fd); |
| 1443 | if (!file) |
| 1444 | goto out; |
| 1445 | } |
| 1446 | |
| 1447 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); |
| 1448 | |
| 1449 | retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
| 1450 | |
| 1451 | if (file) |
| 1452 | fput(file); |
| 1453 | out: |
| 1454 | return retval; |
| 1455 | } |
| 1456 | |
| 1457 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
| 1458 | struct mmap_arg_struct { |
| 1459 | unsigned long addr; |
| 1460 | unsigned long len; |
| 1461 | unsigned long prot; |
| 1462 | unsigned long flags; |
| 1463 | unsigned long fd; |
| 1464 | unsigned long offset; |
| 1465 | }; |
| 1466 | |
| 1467 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) |
| 1468 | { |
| 1469 | struct mmap_arg_struct a; |
| 1470 | |
| 1471 | if (copy_from_user(&a, arg, sizeof(a))) |
| 1472 | return -EFAULT; |
| 1473 | if (offset_in_page(a.offset)) |
| 1474 | return -EINVAL; |
| 1475 | |
| 1476 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, |
| 1477 | a.offset >> PAGE_SHIFT); |
| 1478 | } |
| 1479 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ |
| 1480 | |
| 1481 | /* |
| 1482 | * split a vma into two pieces at address 'addr', a new vma is allocated either |
| 1483 | * for the first part or the tail. |
| 1484 | */ |
| 1485 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1486 | unsigned long addr, int new_below) |
| 1487 | { |
| 1488 | struct vm_area_struct *new; |
| 1489 | struct vm_region *region; |
| 1490 | unsigned long npages; |
| 1491 | |
| 1492 | /* we're only permitted to split anonymous regions (these should have |
| 1493 | * only a single usage on the region) */ |
| 1494 | if (vma->vm_file) |
| 1495 | return -ENOMEM; |
| 1496 | |
| 1497 | if (mm->map_count >= sysctl_max_map_count) |
| 1498 | return -ENOMEM; |
| 1499 | |
| 1500 | region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL); |
| 1501 | if (!region) |
| 1502 | return -ENOMEM; |
| 1503 | |
| 1504 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
| 1505 | if (!new) { |
| 1506 | kmem_cache_free(vm_region_jar, region); |
| 1507 | return -ENOMEM; |
| 1508 | } |
| 1509 | |
| 1510 | /* most fields are the same, copy all, and then fixup */ |
| 1511 | *new = *vma; |
| 1512 | *region = *vma->vm_region; |
| 1513 | new->vm_region = region; |
| 1514 | |
| 1515 | npages = (addr - vma->vm_start) >> PAGE_SHIFT; |
| 1516 | |
| 1517 | if (new_below) { |
| 1518 | region->vm_top = region->vm_end = new->vm_end = addr; |
| 1519 | } else { |
| 1520 | region->vm_start = new->vm_start = addr; |
| 1521 | region->vm_pgoff = new->vm_pgoff += npages; |
| 1522 | } |
| 1523 | |
| 1524 | if (new->vm_ops && new->vm_ops->open) |
| 1525 | new->vm_ops->open(new); |
| 1526 | |
| 1527 | delete_vma_from_mm(vma); |
| 1528 | down_write(&nommu_region_sem); |
| 1529 | delete_nommu_region(vma->vm_region); |
| 1530 | if (new_below) { |
| 1531 | vma->vm_region->vm_start = vma->vm_start = addr; |
| 1532 | vma->vm_region->vm_pgoff = vma->vm_pgoff += npages; |
| 1533 | } else { |
| 1534 | vma->vm_region->vm_end = vma->vm_end = addr; |
| 1535 | vma->vm_region->vm_top = addr; |
| 1536 | } |
| 1537 | add_nommu_region(vma->vm_region); |
| 1538 | add_nommu_region(new->vm_region); |
| 1539 | up_write(&nommu_region_sem); |
| 1540 | add_vma_to_mm(mm, vma); |
| 1541 | add_vma_to_mm(mm, new); |
| 1542 | return 0; |
| 1543 | } |
| 1544 | |
| 1545 | /* |
| 1546 | * shrink a VMA by removing the specified chunk from either the beginning or |
| 1547 | * the end |
| 1548 | */ |
| 1549 | static int shrink_vma(struct mm_struct *mm, |
| 1550 | struct vm_area_struct *vma, |
| 1551 | unsigned long from, unsigned long to) |
| 1552 | { |
| 1553 | struct vm_region *region; |
| 1554 | |
| 1555 | /* adjust the VMA's pointers, which may reposition it in the MM's tree |
| 1556 | * and list */ |
| 1557 | delete_vma_from_mm(vma); |
| 1558 | if (from > vma->vm_start) |
| 1559 | vma->vm_end = from; |
| 1560 | else |
| 1561 | vma->vm_start = to; |
| 1562 | add_vma_to_mm(mm, vma); |
| 1563 | |
| 1564 | /* cut the backing region down to size */ |
| 1565 | region = vma->vm_region; |
| 1566 | BUG_ON(region->vm_usage != 1); |
| 1567 | |
| 1568 | down_write(&nommu_region_sem); |
| 1569 | delete_nommu_region(region); |
| 1570 | if (from > region->vm_start) { |
| 1571 | to = region->vm_top; |
| 1572 | region->vm_top = region->vm_end = from; |
| 1573 | } else { |
| 1574 | region->vm_start = to; |
| 1575 | } |
| 1576 | add_nommu_region(region); |
| 1577 | up_write(&nommu_region_sem); |
| 1578 | |
| 1579 | free_page_series(from, to); |
| 1580 | return 0; |
| 1581 | } |
| 1582 | |
| 1583 | /* |
| 1584 | * release a mapping |
| 1585 | * - under NOMMU conditions the chunk to be unmapped must be backed by a single |
| 1586 | * VMA, though it need not cover the whole VMA |
| 1587 | */ |
| 1588 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) |
| 1589 | { |
| 1590 | struct vm_area_struct *vma; |
| 1591 | unsigned long end; |
| 1592 | int ret; |
| 1593 | |
| 1594 | len = PAGE_ALIGN(len); |
| 1595 | if (len == 0) |
| 1596 | return -EINVAL; |
| 1597 | |
| 1598 | end = start + len; |
| 1599 | |
| 1600 | /* find the first potentially overlapping VMA */ |
| 1601 | vma = find_vma(mm, start); |
| 1602 | if (!vma) { |
| 1603 | static int limit; |
| 1604 | if (limit < 5) { |
| 1605 | pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx\n", |
| 1606 | current->pid, current->comm, |
| 1607 | start, start + len - 1); |
| 1608 | limit++; |
| 1609 | } |
| 1610 | return -EINVAL; |
| 1611 | } |
| 1612 | |
| 1613 | /* we're allowed to split an anonymous VMA but not a file-backed one */ |
| 1614 | if (vma->vm_file) { |
| 1615 | do { |
| 1616 | if (start > vma->vm_start) |
| 1617 | return -EINVAL; |
| 1618 | if (end == vma->vm_end) |
| 1619 | goto erase_whole_vma; |
| 1620 | vma = vma->vm_next; |
| 1621 | } while (vma); |
| 1622 | return -EINVAL; |
| 1623 | } else { |
| 1624 | /* the chunk must be a subset of the VMA found */ |
| 1625 | if (start == vma->vm_start && end == vma->vm_end) |
| 1626 | goto erase_whole_vma; |
| 1627 | if (start < vma->vm_start || end > vma->vm_end) |
| 1628 | return -EINVAL; |
| 1629 | if (offset_in_page(start)) |
| 1630 | return -EINVAL; |
| 1631 | if (end != vma->vm_end && offset_in_page(end)) |
| 1632 | return -EINVAL; |
| 1633 | if (start != vma->vm_start && end != vma->vm_end) { |
| 1634 | ret = split_vma(mm, vma, start, 1); |
| 1635 | if (ret < 0) |
| 1636 | return ret; |
| 1637 | } |
| 1638 | return shrink_vma(mm, vma, start, end); |
| 1639 | } |
| 1640 | |
| 1641 | erase_whole_vma: |
| 1642 | delete_vma_from_mm(vma); |
| 1643 | delete_vma(mm, vma); |
| 1644 | return 0; |
| 1645 | } |
| 1646 | EXPORT_SYMBOL(do_munmap); |
| 1647 | |
| 1648 | int vm_munmap(unsigned long addr, size_t len) |
| 1649 | { |
| 1650 | struct mm_struct *mm = current->mm; |
| 1651 | int ret; |
| 1652 | |
| 1653 | down_write(&mm->mmap_sem); |
| 1654 | ret = do_munmap(mm, addr, len); |
| 1655 | up_write(&mm->mmap_sem); |
| 1656 | return ret; |
| 1657 | } |
| 1658 | EXPORT_SYMBOL(vm_munmap); |
| 1659 | |
| 1660 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
| 1661 | { |
| 1662 | return vm_munmap(addr, len); |
| 1663 | } |
| 1664 | |
| 1665 | /* |
| 1666 | * release all the mappings made in a process's VM space |
| 1667 | */ |
| 1668 | void exit_mmap(struct mm_struct *mm) |
| 1669 | { |
| 1670 | struct vm_area_struct *vma; |
| 1671 | |
| 1672 | if (!mm) |
| 1673 | return; |
| 1674 | |
| 1675 | mm->total_vm = 0; |
| 1676 | |
| 1677 | while ((vma = mm->mmap)) { |
| 1678 | mm->mmap = vma->vm_next; |
| 1679 | delete_vma_from_mm(vma); |
| 1680 | delete_vma(mm, vma); |
| 1681 | cond_resched(); |
| 1682 | } |
| 1683 | } |
| 1684 | |
| 1685 | unsigned long vm_brk(unsigned long addr, unsigned long len) |
| 1686 | { |
| 1687 | return -ENOMEM; |
| 1688 | } |
| 1689 | |
| 1690 | /* |
| 1691 | * expand (or shrink) an existing mapping, potentially moving it at the same |
| 1692 | * time (controlled by the MREMAP_MAYMOVE flag and available VM space) |
| 1693 | * |
| 1694 | * under NOMMU conditions, we only permit changing a mapping's size, and only |
| 1695 | * as long as it stays within the region allocated by do_mmap_private() and the |
| 1696 | * block is not shareable |
| 1697 | * |
| 1698 | * MREMAP_FIXED is not supported under NOMMU conditions |
| 1699 | */ |
| 1700 | static unsigned long do_mremap(unsigned long addr, |
| 1701 | unsigned long old_len, unsigned long new_len, |
| 1702 | unsigned long flags, unsigned long new_addr) |
| 1703 | { |
| 1704 | struct vm_area_struct *vma; |
| 1705 | |
| 1706 | /* insanity checks first */ |
| 1707 | old_len = PAGE_ALIGN(old_len); |
| 1708 | new_len = PAGE_ALIGN(new_len); |
| 1709 | if (old_len == 0 || new_len == 0) |
| 1710 | return (unsigned long) -EINVAL; |
| 1711 | |
| 1712 | if (offset_in_page(addr)) |
| 1713 | return -EINVAL; |
| 1714 | |
| 1715 | if (flags & MREMAP_FIXED && new_addr != addr) |
| 1716 | return (unsigned long) -EINVAL; |
| 1717 | |
| 1718 | vma = find_vma_exact(current->mm, addr, old_len); |
| 1719 | if (!vma) |
| 1720 | return (unsigned long) -EINVAL; |
| 1721 | |
| 1722 | if (vma->vm_end != vma->vm_start + old_len) |
| 1723 | return (unsigned long) -EFAULT; |
| 1724 | |
| 1725 | if (vma->vm_flags & VM_MAYSHARE) |
| 1726 | return (unsigned long) -EPERM; |
| 1727 | |
| 1728 | if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start) |
| 1729 | return (unsigned long) -ENOMEM; |
| 1730 | |
| 1731 | /* all checks complete - do it */ |
| 1732 | vma->vm_end = vma->vm_start + new_len; |
| 1733 | return vma->vm_start; |
| 1734 | } |
| 1735 | |
| 1736 | SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, |
| 1737 | unsigned long, new_len, unsigned long, flags, |
| 1738 | unsigned long, new_addr) |
| 1739 | { |
| 1740 | unsigned long ret; |
| 1741 | |
| 1742 | down_write(¤t->mm->mmap_sem); |
| 1743 | ret = do_mremap(addr, old_len, new_len, flags, new_addr); |
| 1744 | up_write(¤t->mm->mmap_sem); |
| 1745 | return ret; |
| 1746 | } |
| 1747 | |
| 1748 | struct page *follow_page_mask(struct vm_area_struct *vma, |
| 1749 | unsigned long address, unsigned int flags, |
| 1750 | unsigned int *page_mask) |
| 1751 | { |
| 1752 | *page_mask = 0; |
| 1753 | return NULL; |
| 1754 | } |
| 1755 | |
| 1756 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
| 1757 | unsigned long pfn, unsigned long size, pgprot_t prot) |
| 1758 | { |
| 1759 | if (addr != (pfn << PAGE_SHIFT)) |
| 1760 | return -EINVAL; |
| 1761 | |
| 1762 | vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; |
| 1763 | return 0; |
| 1764 | } |
| 1765 | EXPORT_SYMBOL(remap_pfn_range); |
| 1766 | |
| 1767 | int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) |
| 1768 | { |
| 1769 | unsigned long pfn = start >> PAGE_SHIFT; |
| 1770 | unsigned long vm_len = vma->vm_end - vma->vm_start; |
| 1771 | |
| 1772 | pfn += vma->vm_pgoff; |
| 1773 | return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); |
| 1774 | } |
| 1775 | EXPORT_SYMBOL(vm_iomap_memory); |
| 1776 | |
| 1777 | int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, |
| 1778 | unsigned long pgoff) |
| 1779 | { |
| 1780 | unsigned int size = vma->vm_end - vma->vm_start; |
| 1781 | |
| 1782 | if (!(vma->vm_flags & VM_USERMAP)) |
| 1783 | return -EINVAL; |
| 1784 | |
| 1785 | vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT)); |
| 1786 | vma->vm_end = vma->vm_start + size; |
| 1787 | |
| 1788 | return 0; |
| 1789 | } |
| 1790 | EXPORT_SYMBOL(remap_vmalloc_range); |
| 1791 | |
| 1792 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, |
| 1793 | unsigned long len, unsigned long pgoff, unsigned long flags) |
| 1794 | { |
| 1795 | return -ENOMEM; |
| 1796 | } |
| 1797 | |
| 1798 | void unmap_mapping_range(struct address_space *mapping, |
| 1799 | loff_t const holebegin, loff_t const holelen, |
| 1800 | int even_cows) |
| 1801 | { |
| 1802 | } |
| 1803 | EXPORT_SYMBOL(unmap_mapping_range); |
| 1804 | |
| 1805 | int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| 1806 | { |
| 1807 | BUG(); |
| 1808 | return 0; |
| 1809 | } |
| 1810 | EXPORT_SYMBOL(filemap_fault); |
| 1811 | |
| 1812 | void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf) |
| 1813 | { |
| 1814 | BUG(); |
| 1815 | } |
| 1816 | EXPORT_SYMBOL(filemap_map_pages); |
| 1817 | |
| 1818 | static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, |
| 1819 | unsigned long addr, void *buf, int len, int write) |
| 1820 | { |
| 1821 | struct vm_area_struct *vma; |
| 1822 | |
| 1823 | down_read(&mm->mmap_sem); |
| 1824 | |
| 1825 | /* the access must start within one of the target process's mappings */ |
| 1826 | vma = find_vma(mm, addr); |
| 1827 | if (vma) { |
| 1828 | /* don't overrun this mapping */ |
| 1829 | if (addr + len >= vma->vm_end) |
| 1830 | len = vma->vm_end - addr; |
| 1831 | |
| 1832 | /* only read or write mappings where it is permitted */ |
| 1833 | if (write && vma->vm_flags & VM_MAYWRITE) |
| 1834 | copy_to_user_page(vma, NULL, addr, |
| 1835 | (void *) addr, buf, len); |
| 1836 | else if (!write && vma->vm_flags & VM_MAYREAD) |
| 1837 | copy_from_user_page(vma, NULL, addr, |
| 1838 | buf, (void *) addr, len); |
| 1839 | else |
| 1840 | len = 0; |
| 1841 | } else { |
| 1842 | len = 0; |
| 1843 | } |
| 1844 | |
| 1845 | up_read(&mm->mmap_sem); |
| 1846 | |
| 1847 | return len; |
| 1848 | } |
| 1849 | |
| 1850 | /** |
| 1851 | * @access_remote_vm - access another process' address space |
| 1852 | * @mm: the mm_struct of the target address space |
| 1853 | * @addr: start address to access |
| 1854 | * @buf: source or destination buffer |
| 1855 | * @len: number of bytes to transfer |
| 1856 | * @write: whether the access is a write |
| 1857 | * |
| 1858 | * The caller must hold a reference on @mm. |
| 1859 | */ |
| 1860 | int access_remote_vm(struct mm_struct *mm, unsigned long addr, |
| 1861 | void *buf, int len, int write) |
| 1862 | { |
| 1863 | return __access_remote_vm(NULL, mm, addr, buf, len, write); |
| 1864 | } |
| 1865 | |
| 1866 | /* |
| 1867 | * Access another process' address space. |
| 1868 | * - source/target buffer must be kernel space |
| 1869 | */ |
| 1870 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) |
| 1871 | { |
| 1872 | struct mm_struct *mm; |
| 1873 | |
| 1874 | if (addr + len < addr) |
| 1875 | return 0; |
| 1876 | |
| 1877 | mm = get_task_mm(tsk); |
| 1878 | if (!mm) |
| 1879 | return 0; |
| 1880 | |
| 1881 | len = __access_remote_vm(tsk, mm, addr, buf, len, write); |
| 1882 | |
| 1883 | mmput(mm); |
| 1884 | return len; |
| 1885 | } |
| 1886 | |
| 1887 | /** |
| 1888 | * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode |
| 1889 | * @inode: The inode to check |
| 1890 | * @size: The current filesize of the inode |
| 1891 | * @newsize: The proposed filesize of the inode |
| 1892 | * |
| 1893 | * Check the shared mappings on an inode on behalf of a shrinking truncate to |
| 1894 | * make sure that that any outstanding VMAs aren't broken and then shrink the |
| 1895 | * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't |
| 1896 | * automatically grant mappings that are too large. |
| 1897 | */ |
| 1898 | int nommu_shrink_inode_mappings(struct inode *inode, size_t size, |
| 1899 | size_t newsize) |
| 1900 | { |
| 1901 | struct vm_area_struct *vma; |
| 1902 | struct vm_region *region; |
| 1903 | pgoff_t low, high; |
| 1904 | size_t r_size, r_top; |
| 1905 | |
| 1906 | low = newsize >> PAGE_SHIFT; |
| 1907 | high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1908 | |
| 1909 | down_write(&nommu_region_sem); |
| 1910 | i_mmap_lock_read(inode->i_mapping); |
| 1911 | |
| 1912 | /* search for VMAs that fall within the dead zone */ |
| 1913 | vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) { |
| 1914 | /* found one - only interested if it's shared out of the page |
| 1915 | * cache */ |
| 1916 | if (vma->vm_flags & VM_SHARED) { |
| 1917 | i_mmap_unlock_read(inode->i_mapping); |
| 1918 | up_write(&nommu_region_sem); |
| 1919 | return -ETXTBSY; /* not quite true, but near enough */ |
| 1920 | } |
| 1921 | } |
| 1922 | |
| 1923 | /* reduce any regions that overlap the dead zone - if in existence, |
| 1924 | * these will be pointed to by VMAs that don't overlap the dead zone |
| 1925 | * |
| 1926 | * we don't check for any regions that start beyond the EOF as there |
| 1927 | * shouldn't be any |
| 1928 | */ |
| 1929 | vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) { |
| 1930 | if (!(vma->vm_flags & VM_SHARED)) |
| 1931 | continue; |
| 1932 | |
| 1933 | region = vma->vm_region; |
| 1934 | r_size = region->vm_top - region->vm_start; |
| 1935 | r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size; |
| 1936 | |
| 1937 | if (r_top > newsize) { |
| 1938 | region->vm_top -= r_top - newsize; |
| 1939 | if (region->vm_end > region->vm_top) |
| 1940 | region->vm_end = region->vm_top; |
| 1941 | } |
| 1942 | } |
| 1943 | |
| 1944 | i_mmap_unlock_read(inode->i_mapping); |
| 1945 | up_write(&nommu_region_sem); |
| 1946 | return 0; |
| 1947 | } |
| 1948 | |
| 1949 | /* |
| 1950 | * Initialise sysctl_user_reserve_kbytes. |
| 1951 | * |
| 1952 | * This is intended to prevent a user from starting a single memory hogging |
| 1953 | * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER |
| 1954 | * mode. |
| 1955 | * |
| 1956 | * The default value is min(3% of free memory, 128MB) |
| 1957 | * 128MB is enough to recover with sshd/login, bash, and top/kill. |
| 1958 | */ |
| 1959 | static int __meminit init_user_reserve(void) |
| 1960 | { |
| 1961 | unsigned long free_kbytes; |
| 1962 | |
| 1963 | free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); |
| 1964 | |
| 1965 | sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); |
| 1966 | return 0; |
| 1967 | } |
| 1968 | subsys_initcall(init_user_reserve); |
| 1969 | |
| 1970 | /* |
| 1971 | * Initialise sysctl_admin_reserve_kbytes. |
| 1972 | * |
| 1973 | * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin |
| 1974 | * to log in and kill a memory hogging process. |
| 1975 | * |
| 1976 | * Systems with more than 256MB will reserve 8MB, enough to recover |
| 1977 | * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will |
| 1978 | * only reserve 3% of free pages by default. |
| 1979 | */ |
| 1980 | static int __meminit init_admin_reserve(void) |
| 1981 | { |
| 1982 | unsigned long free_kbytes; |
| 1983 | |
| 1984 | free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); |
| 1985 | |
| 1986 | sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); |
| 1987 | return 0; |
| 1988 | } |
| 1989 | subsys_initcall(init_admin_reserve); |