Fix USB storage hang on command abort
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / nommu.c
blobed75bc962fbe913f8a5835c0a9bc43170582dd7f
1 /*
2 * linux/mm/nommu.c
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).
7 * See Documentation/nommu-mmap.txt
9 * Copyright (c) 2004-2005 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 Paul Mundt <lethal@linux-sh.org>
16 #include <linux/module.h>
17 #include <linux/mm.h>
18 #include <linux/mman.h>
19 #include <linux/swap.h>
20 #include <linux/file.h>
21 #include <linux/highmem.h>
22 #include <linux/pagemap.h>
23 #include <linux/slab.h>
24 #include <linux/vmalloc.h>
25 #include <linux/tracehook.h>
26 #include <linux/blkdev.h>
27 #include <linux/backing-dev.h>
28 #include <linux/mount.h>
29 #include <linux/personality.h>
30 #include <linux/security.h>
31 #include <linux/syscalls.h>
33 #include <asm/uaccess.h>
34 #include <asm/tlb.h>
35 #include <asm/tlbflush.h>
37 void *high_memory;
38 struct page *mem_map;
39 unsigned long max_mapnr;
40 unsigned long num_physpages;
41 unsigned long askedalloc, realalloc;
42 atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
43 int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
44 int sysctl_overcommit_ratio = 50; /* default is 50% */
45 int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
46 int heap_stack_gap = 0;
48 EXPORT_SYMBOL(mem_map);
49 EXPORT_SYMBOL(num_physpages);
51 /* list of shareable VMAs */
52 struct rb_root nommu_vma_tree = RB_ROOT;
53 DECLARE_RWSEM(nommu_vma_sem);
55 struct vm_operations_struct generic_file_vm_ops = {
59 * Handle all mappings that got truncated by a "truncate()"
60 * system call.
62 * NOTE! We have to be ready to update the memory sharing
63 * between the file and the memory map for a potential last
64 * incomplete page. Ugly, but necessary.
66 int vmtruncate(struct inode *inode, loff_t offset)
68 struct address_space *mapping = inode->i_mapping;
69 unsigned long limit;
71 if (inode->i_size < offset)
72 goto do_expand;
73 i_size_write(inode, offset);
75 truncate_inode_pages(mapping, offset);
76 goto out_truncate;
78 do_expand:
79 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
80 if (limit != RLIM_INFINITY && offset > limit)
81 goto out_sig;
82 if (offset > inode->i_sb->s_maxbytes)
83 goto out;
84 i_size_write(inode, offset);
86 out_truncate:
87 if (inode->i_op && inode->i_op->truncate)
88 inode->i_op->truncate(inode);
89 return 0;
90 out_sig:
91 send_sig(SIGXFSZ, current, 0);
92 out:
93 return -EFBIG;
96 EXPORT_SYMBOL(vmtruncate);
99 * Return the total memory allocated for this pointer, not
100 * just what the caller asked for.
102 * Doesn't have to be accurate, i.e. may have races.
104 unsigned int kobjsize(const void *objp)
106 struct page *page;
109 * If the object we have should not have ksize performed on it,
110 * return size of 0
112 if (!objp || !virt_addr_valid(objp))
113 return 0;
115 page = virt_to_head_page(objp);
118 * If the allocator sets PageSlab, we know the pointer came from
119 * kmalloc().
121 if (PageSlab(page))
122 return ksize(objp);
125 * The ksize() function is only guaranteed to work for pointers
126 * returned by kmalloc(). So handle arbitrary pointers here.
128 return PAGE_SIZE << compound_order(page);
132 * get a list of pages in an address range belonging to the specified process
133 * and indicate the VMA that covers each page
134 * - this is potentially dodgy as we may end incrementing the page count of a
135 * slab page or a secondary page from a compound page
136 * - don't permit access to VMAs that don't support it, such as I/O mappings
138 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
139 unsigned long start, int len, int write, int force,
140 struct page **pages, struct vm_area_struct **vmas)
142 struct vm_area_struct *vma;
143 unsigned long vm_flags;
144 int i;
146 /* calculate required read or write permissions.
147 * - if 'force' is set, we only require the "MAY" flags.
149 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
150 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
152 for (i = 0; i < len; i++) {
153 vma = find_vma(mm, start);
154 if (!vma)
155 goto finish_or_fault;
157 /* protect what we can, including chardevs */
158 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
159 !(vm_flags & vma->vm_flags))
160 goto finish_or_fault;
162 if (pages) {
163 pages[i] = virt_to_page(start);
164 if (pages[i])
165 page_cache_get(pages[i]);
167 if (vmas)
168 vmas[i] = vma;
169 start += PAGE_SIZE;
172 return i;
174 finish_or_fault:
175 return i ? : -EFAULT;
177 EXPORT_SYMBOL(get_user_pages);
179 DEFINE_RWLOCK(vmlist_lock);
180 struct vm_struct *vmlist;
182 void vfree(const void *addr)
184 kfree(addr);
186 EXPORT_SYMBOL(vfree);
188 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
191 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
192 * returns only a logical address.
194 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
196 EXPORT_SYMBOL(__vmalloc);
198 void *vmalloc_user(unsigned long size)
200 void *ret;
202 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
203 PAGE_KERNEL);
204 if (ret) {
205 struct vm_area_struct *vma;
207 down_write(&current->mm->mmap_sem);
208 vma = find_vma(current->mm, (unsigned long)ret);
209 if (vma)
210 vma->vm_flags |= VM_USERMAP;
211 up_write(&current->mm->mmap_sem);
214 return ret;
216 EXPORT_SYMBOL(vmalloc_user);
218 struct page *vmalloc_to_page(const void *addr)
220 return virt_to_page(addr);
222 EXPORT_SYMBOL(vmalloc_to_page);
224 unsigned long vmalloc_to_pfn(const void *addr)
226 return page_to_pfn(virt_to_page(addr));
228 EXPORT_SYMBOL(vmalloc_to_pfn);
230 long vread(char *buf, char *addr, unsigned long count)
232 memcpy(buf, addr, count);
233 return count;
236 long vwrite(char *buf, char *addr, unsigned long count)
238 /* Don't allow overflow */
239 if ((unsigned long) addr + count < count)
240 count = -(unsigned long) addr;
242 memcpy(addr, buf, count);
243 return(count);
247 * vmalloc - allocate virtually continguos memory
249 * @size: allocation size
251 * Allocate enough pages to cover @size from the page level
252 * allocator and map them into continguos kernel virtual space.
254 * For tight control over page level allocator and protection flags
255 * use __vmalloc() instead.
257 void *vmalloc(unsigned long size)
259 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
261 EXPORT_SYMBOL(vmalloc);
263 void *vmalloc_node(unsigned long size, int node)
265 return vmalloc(size);
267 EXPORT_SYMBOL(vmalloc_node);
269 #ifndef PAGE_KERNEL_EXEC
270 # define PAGE_KERNEL_EXEC PAGE_KERNEL
271 #endif
274 * vmalloc_exec - allocate virtually contiguous, executable memory
275 * @size: allocation size
277 * Kernel-internal function to allocate enough pages to cover @size
278 * the page level allocator and map them into contiguous and
279 * executable kernel virtual space.
281 * For tight control over page level allocator and protection flags
282 * use __vmalloc() instead.
285 void *vmalloc_exec(unsigned long size)
287 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
291 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
292 * @size: allocation size
294 * Allocate enough 32bit PA addressable pages to cover @size from the
295 * page level allocator and map them into continguos kernel virtual space.
297 void *vmalloc_32(unsigned long size)
299 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
301 EXPORT_SYMBOL(vmalloc_32);
304 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
305 * @size: allocation size
307 * The resulting memory area is 32bit addressable and zeroed so it can be
308 * mapped to userspace without leaking data.
310 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
311 * remap_vmalloc_range() are permissible.
313 void *vmalloc_32_user(unsigned long size)
316 * We'll have to sort out the ZONE_DMA bits for 64-bit,
317 * but for now this can simply use vmalloc_user() directly.
319 return vmalloc_user(size);
321 EXPORT_SYMBOL(vmalloc_32_user);
323 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
325 BUG();
326 return NULL;
328 EXPORT_SYMBOL(vmap);
330 void vunmap(const void *addr)
332 BUG();
334 EXPORT_SYMBOL(vunmap);
337 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
338 * have one.
340 void __attribute__((weak)) vmalloc_sync_all(void)
344 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
345 struct page *page)
347 return -EINVAL;
349 EXPORT_SYMBOL(vm_insert_page);
352 * sys_brk() for the most part doesn't need the global kernel
353 * lock, except when an application is doing something nasty
354 * like trying to un-brk an area that has already been mapped
355 * to a regular file. in this case, the unmapping will need
356 * to invoke file system routines that need the global lock.
358 asmlinkage unsigned long sys_brk(unsigned long brk)
360 struct mm_struct *mm = current->mm;
362 if (brk < mm->start_brk || brk > mm->context.end_brk)
363 return mm->brk;
365 if (mm->brk == brk)
366 return mm->brk;
369 * Always allow shrinking brk
371 if (brk <= mm->brk) {
372 mm->brk = brk;
373 return brk;
377 * Ok, looks good - let it rip.
379 return mm->brk = brk;
382 #ifdef DEBUG
383 static void show_process_blocks(void)
385 struct vm_list_struct *vml;
387 printk("Process blocks %d:", current->pid);
389 for (vml = &current->mm->context.vmlist; vml; vml = vml->next) {
390 printk(" %p: %p", vml, vml->vma);
391 if (vml->vma)
392 printk(" (%d @%lx #%d)",
393 kobjsize((void *) vml->vma->vm_start),
394 vml->vma->vm_start,
395 atomic_read(&vml->vma->vm_usage));
396 printk(vml->next ? " ->" : ".\n");
399 #endif /* DEBUG */
402 * add a VMA into a process's mm_struct in the appropriate place in the list
403 * - should be called with mm->mmap_sem held writelocked
405 static void add_vma_to_mm(struct mm_struct *mm, struct vm_list_struct *vml)
407 struct vm_list_struct **ppv;
409 for (ppv = &current->mm->context.vmlist; *ppv; ppv = &(*ppv)->next)
410 if ((*ppv)->vma->vm_start > vml->vma->vm_start)
411 break;
413 vml->next = *ppv;
414 *ppv = vml;
418 * look up the first VMA in which addr resides, NULL if none
419 * - should be called with mm->mmap_sem at least held readlocked
421 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
423 struct vm_list_struct *loop, *vml;
425 /* search the vm_start ordered list */
426 vml = NULL;
427 for (loop = mm->context.vmlist; loop; loop = loop->next) {
428 if (loop->vma->vm_start > addr)
429 break;
430 vml = loop;
433 if (vml && vml->vma->vm_end > addr)
434 return vml->vma;
436 return NULL;
438 EXPORT_SYMBOL(find_vma);
441 * find a VMA
442 * - we don't extend stack VMAs under NOMMU conditions
444 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
446 return find_vma(mm, addr);
449 int expand_stack(struct vm_area_struct *vma, unsigned long address)
451 return -ENOMEM;
455 * look up the first VMA exactly that exactly matches addr
456 * - should be called with mm->mmap_sem at least held readlocked
458 static inline struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
459 unsigned long addr)
461 struct vm_list_struct *vml;
463 /* search the vm_start ordered list */
464 for (vml = mm->context.vmlist; vml; vml = vml->next) {
465 if (vml->vma->vm_start == addr)
466 return vml->vma;
467 if (vml->vma->vm_start > addr)
468 break;
471 return NULL;
475 * find a VMA in the global tree
477 static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
479 struct vm_area_struct *vma;
480 struct rb_node *n = nommu_vma_tree.rb_node;
482 while (n) {
483 vma = rb_entry(n, struct vm_area_struct, vm_rb);
485 if (start < vma->vm_start)
486 n = n->rb_left;
487 else if (start > vma->vm_start)
488 n = n->rb_right;
489 else
490 return vma;
493 return NULL;
497 * add a VMA in the global tree
499 static void add_nommu_vma(struct vm_area_struct *vma)
501 struct vm_area_struct *pvma;
502 struct address_space *mapping;
503 struct rb_node **p = &nommu_vma_tree.rb_node;
504 struct rb_node *parent = NULL;
506 /* add the VMA to the mapping */
507 if (vma->vm_file) {
508 mapping = vma->vm_file->f_mapping;
510 flush_dcache_mmap_lock(mapping);
511 vma_prio_tree_insert(vma, &mapping->i_mmap);
512 flush_dcache_mmap_unlock(mapping);
515 /* add the VMA to the master list */
516 while (*p) {
517 parent = *p;
518 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
520 if (vma->vm_start < pvma->vm_start) {
521 p = &(*p)->rb_left;
523 else if (vma->vm_start > pvma->vm_start) {
524 p = &(*p)->rb_right;
526 else {
527 /* mappings are at the same address - this can only
528 * happen for shared-mem chardevs and shared file
529 * mappings backed by ramfs/tmpfs */
530 BUG_ON(!(pvma->vm_flags & VM_SHARED));
532 if (vma < pvma)
533 p = &(*p)->rb_left;
534 else if (vma > pvma)
535 p = &(*p)->rb_right;
536 else
537 BUG();
541 rb_link_node(&vma->vm_rb, parent, p);
542 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
546 * delete a VMA from the global list
548 static void delete_nommu_vma(struct vm_area_struct *vma)
550 struct address_space *mapping;
552 /* remove the VMA from the mapping */
553 if (vma->vm_file) {
554 mapping = vma->vm_file->f_mapping;
556 flush_dcache_mmap_lock(mapping);
557 vma_prio_tree_remove(vma, &mapping->i_mmap);
558 flush_dcache_mmap_unlock(mapping);
561 /* remove from the master list */
562 rb_erase(&vma->vm_rb, &nommu_vma_tree);
566 * determine whether a mapping should be permitted and, if so, what sort of
567 * mapping we're capable of supporting
569 static int validate_mmap_request(struct file *file,
570 unsigned long addr,
571 unsigned long len,
572 unsigned long prot,
573 unsigned long flags,
574 unsigned long pgoff,
575 unsigned long *_capabilities)
577 unsigned long capabilities;
578 unsigned long reqprot = prot;
579 int ret;
581 /* do the simple checks first */
582 if (flags & MAP_FIXED || addr) {
583 printk(KERN_DEBUG
584 "%d: Can't do fixed-address/overlay mmap of RAM\n",
585 current->pid);
586 return -EINVAL;
589 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
590 (flags & MAP_TYPE) != MAP_SHARED)
591 return -EINVAL;
593 if (!len)
594 return -EINVAL;
596 /* Careful about overflows.. */
597 len = PAGE_ALIGN(len);
598 if (!len || len > TASK_SIZE)
599 return -ENOMEM;
601 /* offset overflow? */
602 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
603 return -EOVERFLOW;
605 if (file) {
606 /* validate file mapping requests */
607 struct address_space *mapping;
609 /* files must support mmap */
610 if (!file->f_op || !file->f_op->mmap)
611 return -ENODEV;
613 /* work out if what we've got could possibly be shared
614 * - we support chardevs that provide their own "memory"
615 * - we support files/blockdevs that are memory backed
617 mapping = file->f_mapping;
618 if (!mapping)
619 mapping = file->f_path.dentry->d_inode->i_mapping;
621 capabilities = 0;
622 if (mapping && mapping->backing_dev_info)
623 capabilities = mapping->backing_dev_info->capabilities;
625 if (!capabilities) {
626 /* no explicit capabilities set, so assume some
627 * defaults */
628 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
629 case S_IFREG:
630 case S_IFBLK:
631 capabilities = BDI_CAP_MAP_COPY;
632 break;
634 case S_IFCHR:
635 capabilities =
636 BDI_CAP_MAP_DIRECT |
637 BDI_CAP_READ_MAP |
638 BDI_CAP_WRITE_MAP;
639 break;
641 default:
642 return -EINVAL;
646 /* eliminate any capabilities that we can't support on this
647 * device */
648 if (!file->f_op->get_unmapped_area)
649 capabilities &= ~BDI_CAP_MAP_DIRECT;
650 if (!file->f_op->read)
651 capabilities &= ~BDI_CAP_MAP_COPY;
653 if (flags & MAP_SHARED) {
654 /* do checks for writing, appending and locking */
655 if ((prot & PROT_WRITE) &&
656 !(file->f_mode & FMODE_WRITE))
657 return -EACCES;
659 if (IS_APPEND(file->f_path.dentry->d_inode) &&
660 (file->f_mode & FMODE_WRITE))
661 return -EACCES;
663 if (locks_verify_locked(file->f_path.dentry->d_inode))
664 return -EAGAIN;
666 if (!(capabilities & BDI_CAP_MAP_DIRECT))
667 return -ENODEV;
669 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
670 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
671 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
673 printk("MAP_SHARED not completely supported on !MMU\n");
674 return -EINVAL;
677 /* we mustn't privatise shared mappings */
678 capabilities &= ~BDI_CAP_MAP_COPY;
680 else {
681 /* we're going to read the file into private memory we
682 * allocate */
683 if (!(capabilities & BDI_CAP_MAP_COPY))
684 return -ENODEV;
686 /* we don't permit a private writable mapping to be
687 * shared with the backing device */
688 if (prot & PROT_WRITE)
689 capabilities &= ~BDI_CAP_MAP_DIRECT;
692 /* handle executable mappings and implied executable
693 * mappings */
694 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
695 if (prot & PROT_EXEC)
696 return -EPERM;
698 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
699 /* handle implication of PROT_EXEC by PROT_READ */
700 if (current->personality & READ_IMPLIES_EXEC) {
701 if (capabilities & BDI_CAP_EXEC_MAP)
702 prot |= PROT_EXEC;
705 else if ((prot & PROT_READ) &&
706 (prot & PROT_EXEC) &&
707 !(capabilities & BDI_CAP_EXEC_MAP)
709 /* backing file is not executable, try to copy */
710 capabilities &= ~BDI_CAP_MAP_DIRECT;
713 else {
714 /* anonymous mappings are always memory backed and can be
715 * privately mapped
717 capabilities = BDI_CAP_MAP_COPY;
719 /* handle PROT_EXEC implication by PROT_READ */
720 if ((prot & PROT_READ) &&
721 (current->personality & READ_IMPLIES_EXEC))
722 prot |= PROT_EXEC;
725 /* allow the security API to have its say */
726 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
727 if (ret < 0)
728 return ret;
730 /* looks okay */
731 *_capabilities = capabilities;
732 return 0;
736 * we've determined that we can make the mapping, now translate what we
737 * now know into VMA flags
739 static unsigned long determine_vm_flags(struct file *file,
740 unsigned long prot,
741 unsigned long flags,
742 unsigned long capabilities)
744 unsigned long vm_flags;
746 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
747 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
748 /* vm_flags |= mm->def_flags; */
750 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
751 /* attempt to share read-only copies of mapped file chunks */
752 if (file && !(prot & PROT_WRITE))
753 vm_flags |= VM_MAYSHARE;
755 else {
756 /* overlay a shareable mapping on the backing device or inode
757 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
758 * romfs/cramfs */
759 if (flags & MAP_SHARED)
760 vm_flags |= VM_MAYSHARE | VM_SHARED;
761 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
762 vm_flags |= VM_MAYSHARE;
765 /* refuse to let anyone share private mappings with this process if
766 * it's being traced - otherwise breakpoints set in it may interfere
767 * with another untraced process
769 if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
770 vm_flags &= ~VM_MAYSHARE;
772 return vm_flags;
776 * set up a shared mapping on a file
778 static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
780 int ret;
782 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
783 if (ret != -ENOSYS)
784 return ret;
786 /* getting an ENOSYS error indicates that direct mmap isn't
787 * possible (as opposed to tried but failed) so we'll fall
788 * through to making a private copy of the data and mapping
789 * that if we can */
790 return -ENODEV;
794 * set up a private mapping or an anonymous shared mapping
796 static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
798 void *base;
799 int ret;
801 /* invoke the file's mapping function so that it can keep track of
802 * shared mappings on devices or memory
803 * - VM_MAYSHARE will be set if it may attempt to share
805 if (vma->vm_file) {
806 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
807 if (ret != -ENOSYS) {
808 /* shouldn't return success if we're not sharing */
809 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
810 return ret; /* success or a real error */
813 /* getting an ENOSYS error indicates that direct mmap isn't
814 * possible (as opposed to tried but failed) so we'll try to
815 * make a private copy of the data and map that instead */
818 /* allocate some memory to hold the mapping
819 * - note that this may not return a page-aligned address if the object
820 * we're allocating is smaller than a page
822 base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
823 if (!base)
824 goto enomem;
826 vma->vm_start = (unsigned long) base;
827 vma->vm_end = vma->vm_start + len;
828 vma->vm_flags |= VM_MAPPED_COPY;
830 #ifdef WARN_ON_SLACK
831 if (len + WARN_ON_SLACK <= kobjsize(result))
832 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
833 len, current->pid, kobjsize(result) - len);
834 #endif
836 if (vma->vm_file) {
837 /* read the contents of a file into the copy */
838 mm_segment_t old_fs;
839 loff_t fpos;
841 fpos = vma->vm_pgoff;
842 fpos <<= PAGE_SHIFT;
844 old_fs = get_fs();
845 set_fs(KERNEL_DS);
846 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
847 set_fs(old_fs);
849 if (ret < 0)
850 goto error_free;
852 /* clear the last little bit */
853 if (ret < len)
854 memset(base + ret, 0, len - ret);
856 } else {
857 /* if it's an anonymous mapping, then just clear it */
858 memset(base, 0, len);
861 return 0;
863 error_free:
864 kfree(base);
865 vma->vm_start = 0;
866 return ret;
868 enomem:
869 printk("Allocation of length %lu from process %d failed\n",
870 len, current->pid);
871 show_free_areas();
872 return -ENOMEM;
876 * handle mapping creation for uClinux
878 unsigned long do_mmap_pgoff(struct file *file,
879 unsigned long addr,
880 unsigned long len,
881 unsigned long prot,
882 unsigned long flags,
883 unsigned long pgoff)
885 struct vm_list_struct *vml = NULL;
886 struct vm_area_struct *vma = NULL;
887 struct rb_node *rb;
888 unsigned long capabilities, vm_flags;
889 void *result;
890 int ret;
892 if (!(flags & MAP_FIXED))
893 addr = round_hint_to_min(addr);
895 /* decide whether we should attempt the mapping, and if so what sort of
896 * mapping */
897 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
898 &capabilities);
899 if (ret < 0)
900 return ret;
902 /* we've determined that we can make the mapping, now translate what we
903 * now know into VMA flags */
904 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
906 /* we're going to need to record the mapping if it works */
907 vml = kzalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
908 if (!vml)
909 goto error_getting_vml;
911 down_write(&nommu_vma_sem);
913 /* if we want to share, we need to check for VMAs created by other
914 * mmap() calls that overlap with our proposed mapping
915 * - we can only share with an exact match on most regular files
916 * - shared mappings on character devices and memory backed files are
917 * permitted to overlap inexactly as far as we are concerned for in
918 * these cases, sharing is handled in the driver or filesystem rather
919 * than here
921 if (vm_flags & VM_MAYSHARE) {
922 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
923 unsigned long vmpglen;
925 /* suppress VMA sharing for shared regions */
926 if (vm_flags & VM_SHARED &&
927 capabilities & BDI_CAP_MAP_DIRECT)
928 goto dont_share_VMAs;
930 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
931 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
933 if (!(vma->vm_flags & VM_MAYSHARE))
934 continue;
936 /* search for overlapping mappings on the same file */
937 if (vma->vm_file->f_path.dentry->d_inode != file->f_path.dentry->d_inode)
938 continue;
940 if (vma->vm_pgoff >= pgoff + pglen)
941 continue;
943 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
944 vmpglen >>= PAGE_SHIFT;
945 if (pgoff >= vma->vm_pgoff + vmpglen)
946 continue;
948 /* handle inexactly overlapping matches between mappings */
949 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
950 if (!(capabilities & BDI_CAP_MAP_DIRECT))
951 goto sharing_violation;
952 continue;
955 /* we've found a VMA we can share */
956 atomic_inc(&vma->vm_usage);
958 vml->vma = vma;
959 result = (void *) vma->vm_start;
960 goto shared;
963 dont_share_VMAs:
964 vma = NULL;
966 /* obtain the address at which to make a shared mapping
967 * - this is the hook for quasi-memory character devices to
968 * tell us the location of a shared mapping
970 if (file && file->f_op->get_unmapped_area) {
971 addr = file->f_op->get_unmapped_area(file, addr, len,
972 pgoff, flags);
973 if (IS_ERR((void *) addr)) {
974 ret = addr;
975 if (ret != (unsigned long) -ENOSYS)
976 goto error;
978 /* the driver refused to tell us where to site
979 * the mapping so we'll have to attempt to copy
980 * it */
981 ret = (unsigned long) -ENODEV;
982 if (!(capabilities & BDI_CAP_MAP_COPY))
983 goto error;
985 capabilities &= ~BDI_CAP_MAP_DIRECT;
990 /* we're going to need a VMA struct as well */
991 vma = kzalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
992 if (!vma)
993 goto error_getting_vma;
995 INIT_LIST_HEAD(&vma->anon_vma_node);
996 atomic_set(&vma->vm_usage, 1);
997 if (file) {
998 get_file(file);
999 if (vm_flags & VM_EXECUTABLE) {
1000 added_exe_file_vma(current->mm);
1001 vma->vm_mm = current->mm;
1004 vma->vm_file = file;
1005 vma->vm_flags = vm_flags;
1006 vma->vm_start = addr;
1007 vma->vm_end = addr + len;
1008 vma->vm_pgoff = pgoff;
1010 vml->vma = vma;
1012 /* set up the mapping */
1013 if (file && vma->vm_flags & VM_SHARED)
1014 ret = do_mmap_shared_file(vma, len);
1015 else
1016 ret = do_mmap_private(vma, len);
1017 if (ret < 0)
1018 goto error;
1020 /* okay... we have a mapping; now we have to register it */
1021 result = (void *) vma->vm_start;
1023 if (vma->vm_flags & VM_MAPPED_COPY) {
1024 realalloc += kobjsize(result);
1025 askedalloc += len;
1028 realalloc += kobjsize(vma);
1029 askedalloc += sizeof(*vma);
1031 current->mm->total_vm += len >> PAGE_SHIFT;
1033 add_nommu_vma(vma);
1035 shared:
1036 realalloc += kobjsize(vml);
1037 askedalloc += sizeof(*vml);
1039 add_vma_to_mm(current->mm, vml);
1041 up_write(&nommu_vma_sem);
1043 if (prot & PROT_EXEC)
1044 flush_icache_range((unsigned long) result,
1045 (unsigned long) result + len);
1047 #ifdef DEBUG
1048 printk("do_mmap:\n");
1049 show_process_blocks();
1050 #endif
1052 return (unsigned long) result;
1054 error:
1055 up_write(&nommu_vma_sem);
1056 kfree(vml);
1057 if (vma) {
1058 if (vma->vm_file) {
1059 fput(vma->vm_file);
1060 if (vma->vm_flags & VM_EXECUTABLE)
1061 removed_exe_file_vma(vma->vm_mm);
1063 kfree(vma);
1065 return ret;
1067 sharing_violation:
1068 up_write(&nommu_vma_sem);
1069 printk("Attempt to share mismatched mappings\n");
1070 kfree(vml);
1071 return -EINVAL;
1073 error_getting_vma:
1074 up_write(&nommu_vma_sem);
1075 kfree(vml);
1076 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
1077 len, current->pid);
1078 show_free_areas();
1079 return -ENOMEM;
1081 error_getting_vml:
1082 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
1083 len, current->pid);
1084 show_free_areas();
1085 return -ENOMEM;
1087 EXPORT_SYMBOL(do_mmap_pgoff);
1090 * handle mapping disposal for uClinux
1092 static void put_vma(struct mm_struct *mm, struct vm_area_struct *vma)
1094 if (vma) {
1095 down_write(&nommu_vma_sem);
1097 if (atomic_dec_and_test(&vma->vm_usage)) {
1098 delete_nommu_vma(vma);
1100 if (vma->vm_ops && vma->vm_ops->close)
1101 vma->vm_ops->close(vma);
1103 /* IO memory and memory shared directly out of the pagecache from
1104 * ramfs/tmpfs mustn't be released here */
1105 if (vma->vm_flags & VM_MAPPED_COPY) {
1106 realalloc -= kobjsize((void *) vma->vm_start);
1107 askedalloc -= vma->vm_end - vma->vm_start;
1108 kfree((void *) vma->vm_start);
1111 realalloc -= kobjsize(vma);
1112 askedalloc -= sizeof(*vma);
1114 if (vma->vm_file) {
1115 fput(vma->vm_file);
1116 if (vma->vm_flags & VM_EXECUTABLE)
1117 removed_exe_file_vma(mm);
1119 kfree(vma);
1122 up_write(&nommu_vma_sem);
1127 * release a mapping
1128 * - under NOMMU conditions the parameters must match exactly to the mapping to
1129 * be removed
1131 int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
1133 struct vm_list_struct *vml, **parent;
1134 unsigned long end = addr + len;
1136 #ifdef DEBUG
1137 printk("do_munmap:\n");
1138 #endif
1140 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next) {
1141 if ((*parent)->vma->vm_start > addr)
1142 break;
1143 if ((*parent)->vma->vm_start == addr &&
1144 ((len == 0) || ((*parent)->vma->vm_end == end)))
1145 goto found;
1148 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
1149 current->pid, current->comm, (void *) addr);
1150 return -EINVAL;
1152 found:
1153 vml = *parent;
1155 put_vma(mm, vml->vma);
1157 *parent = vml->next;
1158 realalloc -= kobjsize(vml);
1159 askedalloc -= sizeof(*vml);
1160 kfree(vml);
1162 update_hiwater_vm(mm);
1163 mm->total_vm -= len >> PAGE_SHIFT;
1165 #ifdef DEBUG
1166 show_process_blocks();
1167 #endif
1169 return 0;
1171 EXPORT_SYMBOL(do_munmap);
1173 asmlinkage long sys_munmap(unsigned long addr, size_t len)
1175 int ret;
1176 struct mm_struct *mm = current->mm;
1178 down_write(&mm->mmap_sem);
1179 ret = do_munmap(mm, addr, len);
1180 up_write(&mm->mmap_sem);
1181 return ret;
1185 * Release all mappings
1187 void exit_mmap(struct mm_struct * mm)
1189 struct vm_list_struct *tmp;
1191 if (mm) {
1192 #ifdef DEBUG
1193 printk("Exit_mmap:\n");
1194 #endif
1196 mm->total_vm = 0;
1198 while ((tmp = mm->context.vmlist)) {
1199 mm->context.vmlist = tmp->next;
1200 put_vma(mm, tmp->vma);
1202 realalloc -= kobjsize(tmp);
1203 askedalloc -= sizeof(*tmp);
1204 kfree(tmp);
1207 #ifdef DEBUG
1208 show_process_blocks();
1209 #endif
1213 unsigned long do_brk(unsigned long addr, unsigned long len)
1215 return -ENOMEM;
1219 * expand (or shrink) an existing mapping, potentially moving it at the same
1220 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1222 * under NOMMU conditions, we only permit changing a mapping's size, and only
1223 * as long as it stays within the hole allocated by the kmalloc() call in
1224 * do_mmap_pgoff() and the block is not shareable
1226 * MREMAP_FIXED is not supported under NOMMU conditions
1228 unsigned long do_mremap(unsigned long addr,
1229 unsigned long old_len, unsigned long new_len,
1230 unsigned long flags, unsigned long new_addr)
1232 struct vm_area_struct *vma;
1234 /* insanity checks first */
1235 if (new_len == 0)
1236 return (unsigned long) -EINVAL;
1238 if (flags & MREMAP_FIXED && new_addr != addr)
1239 return (unsigned long) -EINVAL;
1241 vma = find_vma_exact(current->mm, addr);
1242 if (!vma)
1243 return (unsigned long) -EINVAL;
1245 if (vma->vm_end != vma->vm_start + old_len)
1246 return (unsigned long) -EFAULT;
1248 if (vma->vm_flags & VM_MAYSHARE)
1249 return (unsigned long) -EPERM;
1251 if (new_len > kobjsize((void *) addr))
1252 return (unsigned long) -ENOMEM;
1254 /* all checks complete - do it */
1255 vma->vm_end = vma->vm_start + new_len;
1257 askedalloc -= old_len;
1258 askedalloc += new_len;
1260 return vma->vm_start;
1262 EXPORT_SYMBOL(do_mremap);
1264 asmlinkage unsigned long sys_mremap(unsigned long addr,
1265 unsigned long old_len, unsigned long new_len,
1266 unsigned long flags, unsigned long new_addr)
1268 unsigned long ret;
1270 down_write(&current->mm->mmap_sem);
1271 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1272 up_write(&current->mm->mmap_sem);
1273 return ret;
1276 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1277 unsigned int foll_flags)
1279 return NULL;
1282 int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1283 unsigned long to, unsigned long size, pgprot_t prot)
1285 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1286 return 0;
1288 EXPORT_SYMBOL(remap_pfn_range);
1290 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1291 unsigned long pgoff)
1293 unsigned int size = vma->vm_end - vma->vm_start;
1295 if (!(vma->vm_flags & VM_USERMAP))
1296 return -EINVAL;
1298 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1299 vma->vm_end = vma->vm_start + size;
1301 return 0;
1303 EXPORT_SYMBOL(remap_vmalloc_range);
1305 void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1309 unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1310 unsigned long len, unsigned long pgoff, unsigned long flags)
1312 return -ENOMEM;
1315 void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1319 void unmap_mapping_range(struct address_space *mapping,
1320 loff_t const holebegin, loff_t const holelen,
1321 int even_cows)
1324 EXPORT_SYMBOL(unmap_mapping_range);
1327 * ask for an unmapped area at which to create a mapping on a file
1329 unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1330 unsigned long len, unsigned long pgoff,
1331 unsigned long flags)
1333 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1334 unsigned long, unsigned long);
1336 get_area = current->mm->get_unmapped_area;
1337 if (file && file->f_op && file->f_op->get_unmapped_area)
1338 get_area = file->f_op->get_unmapped_area;
1340 if (!get_area)
1341 return -ENOSYS;
1343 return get_area(file, addr, len, pgoff, flags);
1345 EXPORT_SYMBOL(get_unmapped_area);
1348 * Check that a process has enough memory to allocate a new virtual
1349 * mapping. 0 means there is enough memory for the allocation to
1350 * succeed and -ENOMEM implies there is not.
1352 * We currently support three overcommit policies, which are set via the
1353 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1355 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1356 * Additional code 2002 Jul 20 by Robert Love.
1358 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1360 * Note this is a helper function intended to be used by LSMs which
1361 * wish to use this logic.
1363 int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1365 unsigned long free, allowed;
1367 vm_acct_memory(pages);
1370 * Sometimes we want to use more memory than we have
1372 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1373 return 0;
1375 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1376 unsigned long n;
1378 free = global_page_state(NR_FILE_PAGES);
1379 free += nr_swap_pages;
1382 * Any slabs which are created with the
1383 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1384 * which are reclaimable, under pressure. The dentry
1385 * cache and most inode caches should fall into this
1387 free += global_page_state(NR_SLAB_RECLAIMABLE);
1390 * Leave the last 3% for root
1392 if (!cap_sys_admin)
1393 free -= free / 32;
1395 if (free > pages)
1396 return 0;
1399 * nr_free_pages() is very expensive on large systems,
1400 * only call if we're about to fail.
1402 n = nr_free_pages();
1405 * Leave reserved pages. The pages are not for anonymous pages.
1407 if (n <= totalreserve_pages)
1408 goto error;
1409 else
1410 n -= totalreserve_pages;
1413 * Leave the last 3% for root
1415 if (!cap_sys_admin)
1416 n -= n / 32;
1417 free += n;
1419 if (free > pages)
1420 return 0;
1422 goto error;
1425 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1427 * Leave the last 3% for root
1429 if (!cap_sys_admin)
1430 allowed -= allowed / 32;
1431 allowed += total_swap_pages;
1433 /* Don't let a single process grow too big:
1434 leave 3% of the size of this process for other processes */
1435 allowed -= current->mm->total_vm / 32;
1438 * cast `allowed' as a signed long because vm_committed_space
1439 * sometimes has a negative value
1441 if (atomic_long_read(&vm_committed_space) < (long)allowed)
1442 return 0;
1443 error:
1444 vm_unacct_memory(pages);
1446 return -ENOMEM;
1449 int in_gate_area_no_task(unsigned long addr)
1451 return 0;
1454 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1456 BUG();
1457 return 0;
1459 EXPORT_SYMBOL(filemap_fault);
1462 * Access another process' address space.
1463 * - source/target buffer must be kernel space
1465 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1467 struct vm_area_struct *vma;
1468 struct mm_struct *mm;
1470 if (addr + len < addr)
1471 return 0;
1473 mm = get_task_mm(tsk);
1474 if (!mm)
1475 return 0;
1477 down_read(&mm->mmap_sem);
1479 /* the access must start within one of the target process's mappings */
1480 vma = find_vma(mm, addr);
1481 if (vma) {
1482 /* don't overrun this mapping */
1483 if (addr + len >= vma->vm_end)
1484 len = vma->vm_end - addr;
1486 /* only read or write mappings where it is permitted */
1487 if (write && vma->vm_flags & VM_MAYWRITE)
1488 len -= copy_to_user((void *) addr, buf, len);
1489 else if (!write && vma->vm_flags & VM_MAYREAD)
1490 len -= copy_from_user(buf, (void *) addr, len);
1491 else
1492 len = 0;
1493 } else {
1494 len = 0;
1497 up_read(&mm->mmap_sem);
1498 mmput(mm);
1499 return len;