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* linux/mm/nommu.c
*
* Replacement code for mm functions to support CPU's that don't
* have any form of memory management unit (thus no virtual memory).
*
* Copyright (c) 2004 David Howells <dhowells@redhat.com>
* Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com>
* Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org>
* Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com>
*/
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/swap.h>
#include <linux/file.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/ptrace.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/mount.h>
#include <linux/personality.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <asm/uaccess.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
void *high_memory;
struct page *mem_map;
unsigned long max_mapnr;
unsigned long num_physpages;
unsigned long askedalloc, realalloc;
atomic_t vm_committed_space = ATOMIC_INIT(0);
int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
int sysctl_overcommit_ratio = 50; /* default is 50% */
int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
int heap_stack_gap = 0;
EXPORT_SYMBOL(sysctl_max_map_count);
EXPORT_SYMBOL(mem_map);
/* list of shareable VMAs */
struct rb_root nommu_vma_tree = RB_ROOT;
DECLARE_RWSEM(nommu_vma_sem);
struct vm_operations_struct generic_file_vm_ops = {
};
/*
* Handle all mappings that got truncated by a "truncate()"
* system call.
*
* NOTE! We have to be ready to update the memory sharing
* between the file and the memory map for a potential last
* incomplete page. Ugly, but necessary.
*/
int vmtruncate(struct inode *inode, loff_t offset)
{
struct address_space *mapping = inode->i_mapping;
unsigned long limit;
if (inode->i_size < offset)
goto do_expand;
i_size_write(inode, offset);
truncate_inode_pages(mapping, offset);
goto out_truncate;
do_expand:
limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
if (limit != RLIM_INFINITY && offset > limit)
goto out_sig;
if (offset > inode->i_sb->s_maxbytes)
goto out;
i_size_write(inode, offset);
out_truncate:
if (inode->i_op && inode->i_op->truncate)
inode->i_op->truncate(inode);
return 0;
out_sig:
send_sig(SIGXFSZ, current, 0);
out:
return -EFBIG;
}
EXPORT_SYMBOL(vmtruncate);
/*
* Return the total memory allocated for this pointer, not
* just what the caller asked for.
*
* Doesn't have to be accurate, i.e. may have races.
*/
unsigned int kobjsize(const void *objp)
{
struct page *page;
if (!objp || !((page = virt_to_page(objp))))
return 0;
if (PageSlab(page))
return ksize(objp);
BUG_ON(page->index < 0);
BUG_ON(page->index >= MAX_ORDER);
return (PAGE_SIZE << page->index);
}
/*
* The nommu dodgy version :-)
*/
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, int len, int write, int force,
struct page **pages, struct vm_area_struct **vmas)
{
int i;
static struct vm_area_struct dummy_vma;
for (i = 0; i < len; i++) {
if (pages) {
pages[i] = virt_to_page(start);
if (pages[i])
page_cache_get(pages[i]);
}
if (vmas)
vmas[i] = &dummy_vma;
start += PAGE_SIZE;
}
return(i);
}
DEFINE_RWLOCK(vmlist_lock);
struct vm_struct *vmlist;
void vfree(void *addr)
{
kfree(addr);
}
void *__vmalloc(unsigned long size, int gfp_mask, pgprot_t prot)
{
/*
* kmalloc doesn't like __GFP_HIGHMEM for some reason
*/
return kmalloc(size, gfp_mask & ~__GFP_HIGHMEM);
}
struct page * vmalloc_to_page(void *addr)
{
return virt_to_page(addr);
}
unsigned long vmalloc_to_pfn(void *addr)
{
return page_to_pfn(virt_to_page(addr));
}
long vread(char *buf, char *addr, unsigned long count)
{
memcpy(buf, addr, count);
return count;
}
long vwrite(char *buf, char *addr, unsigned long count)
{
/* Don't allow overflow */
if ((unsigned long) addr + count < count)
count = -(unsigned long) addr;
memcpy(addr, buf, count);
return(count);
}
/*
* vmalloc - allocate virtually continguos memory
*
* @size: allocation size
*
* Allocate enough pages to cover @size from the page level
* allocator and map them into continguos kernel virtual space.
*
* For tight cotrol over page level allocator and protection flags
* use __vmalloc() instead.
*/
void *vmalloc(unsigned long size)
{
return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
}
/*
* vmalloc_32 - allocate virtually continguos memory (32bit addressable)
*
* @size: allocation size
*
* Allocate enough 32bit PA addressable pages to cover @size from the
* page level allocator and map them into continguos kernel virtual space.
*/
void *vmalloc_32(unsigned long size)
{
return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
}
void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
{
BUG();
return NULL;
}
void vunmap(void *addr)
{
BUG();
}
/*
* sys_brk() for the most part doesn't need the global kernel
* lock, except when an application is doing something nasty
* like trying to un-brk an area that has already been mapped
* to a regular file. in this case, the unmapping will need
* to invoke file system routines that need the global lock.
*/
asmlinkage unsigned long sys_brk(unsigned long brk)
{
struct mm_struct *mm = current->mm;
if (brk < mm->start_brk || brk > mm->context.end_brk)
return mm->brk;
if (mm->brk == brk)
return mm->brk;
/*
* Always allow shrinking brk
*/
if (brk <= mm->brk) {
mm->brk = brk;
return brk;
}
/*
* Ok, looks good - let it rip.
*/
return mm->brk = brk;
}
/*
* Combine the mmap "prot" and "flags" argument into one "vm_flags" used
* internally. Essentially, translate the "PROT_xxx" and "MAP_xxx" bits
* into "VM_xxx".
*/
static inline unsigned long calc_vm_flags(unsigned long prot, unsigned long flags)
{
#define _trans(x,bit1,bit2) \
((bit1==bit2)?(x&bit1):(x&bit1)?bit2:0)
unsigned long prot_bits, flag_bits;
prot_bits =
_trans(prot, PROT_READ, VM_READ) |
_trans(prot, PROT_WRITE, VM_WRITE) |
_trans(prot, PROT_EXEC, VM_EXEC);
flag_bits =
_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN) |
_trans(flags, MAP_DENYWRITE, VM_DENYWRITE) |
_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE);
return prot_bits | flag_bits;
#undef _trans
}
#ifdef DEBUG
static void show_process_blocks(void)
{
struct vm_list_struct *vml;
printk("Process blocks %d:", current->pid);
for (vml = ¤t->mm->context.vmlist; vml; vml = vml->next) {
printk(" %p: %p", vml, vml->vma);
if (vml->vma)
printk(" (%d @%lx #%d)",
kobjsize((void *) vml->vma->vm_start),
vml->vma->vm_start,
atomic_read(&vml->vma->vm_usage));
printk(vml->next ? " ->" : ".\n");
}
}
#endif /* DEBUG */
static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
{
struct vm_area_struct *vma;
struct rb_node *n = nommu_vma_tree.rb_node;
while (n) {
vma = rb_entry(n, struct vm_area_struct, vm_rb);
if (start < vma->vm_start)
n = n->rb_left;
else if (start > vma->vm_start)
n = n->rb_right;
else
return vma;
}
return NULL;
}
static void add_nommu_vma(struct vm_area_struct *vma)
{
struct vm_area_struct *pvma;
struct address_space *mapping;
struct rb_node **p = &nommu_vma_tree.rb_node;
struct rb_node *parent = NULL;
/* add the VMA to the mapping */
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
flush_dcache_mmap_lock(mapping);
vma_prio_tree_insert(vma, &mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
}
/* add the VMA to the master list */
while (*p) {
parent = *p;
pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
if (vma->vm_start < pvma->vm_start) {
p = &(*p)->rb_left;
}
else if (vma->vm_start > pvma->vm_start) {
p = &(*p)->rb_right;
}
else {
/* mappings are at the same address - this can only
* happen for shared-mem chardevs and shared file
* mappings backed by ramfs/tmpfs */
BUG_ON(!(pvma->vm_flags & VM_SHARED));
if (vma < pvma)
p = &(*p)->rb_left;
else if (vma > pvma)
p = &(*p)->rb_right;
else
BUG();
}
}
rb_link_node(&vma->vm_rb, parent, p);
rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
}
static void delete_nommu_vma(struct vm_area_struct *vma)
{
struct address_space *mapping;
/* remove the VMA from the mapping */
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
flush_dcache_mmap_lock(mapping);
vma_prio_tree_remove(vma, &mapping->i_mmap);
flush_dcache_mmap_unlock(mapping);
}
/* remove from the master list */
rb_erase(&vma->vm_rb, &nommu_vma_tree);
}
/*
* handle mapping creation for uClinux
*/
unsigned long do_mmap_pgoff(struct file *file,
unsigned long addr,
unsigned long len,
unsigned long prot,
unsigned long flags,
unsigned long pgoff)
{
struct vm_list_struct *vml = NULL;
struct vm_area_struct *vma = NULL;
struct rb_node *rb;
unsigned int vm_flags;
void *result;
int ret, membacked;
/* do the simple checks first */
if (flags & MAP_FIXED || addr) {
printk(KERN_DEBUG "%d: Can't do fixed-address/overlay mmap of RAM\n",
current->pid);
return -EINVAL;
}
if (PAGE_ALIGN(len) == 0)
return addr;
if (len > TASK_SIZE)
return -EINVAL;
/* offset overflow? */
if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
return -EINVAL;
/* validate file mapping requests */
membacked = 0;
if (file) {
/* files must support mmap */
if (!file->f_op || !file->f_op->mmap)
return -ENODEV;
if ((prot & PROT_EXEC) &&
(file->f_vfsmnt->mnt_flags & MNT_NOEXEC))
return -EPERM;
/* work out if what we've got could possibly be shared
* - we support chardevs that provide their own "memory"
* - we support files/blockdevs that are memory backed
*/
if (S_ISCHR(file->f_dentry->d_inode->i_mode)) {
membacked = 1;
}
else {
struct address_space *mapping = file->f_mapping;
if (!mapping)
mapping = file->f_dentry->d_inode->i_mapping;
if (mapping && mapping->backing_dev_info)
membacked = mapping->backing_dev_info->memory_backed;
}
if (flags & MAP_SHARED) {
/* do checks for writing, appending and locking */
if ((prot & PROT_WRITE) && !(file->f_mode & FMODE_WRITE))
return -EACCES;
if (IS_APPEND(file->f_dentry->d_inode) &&
(file->f_mode & FMODE_WRITE))
return -EACCES;
if (locks_verify_locked(file->f_dentry->d_inode))
return -EAGAIN;
if (!membacked) {
printk("MAP_SHARED not completely supported on !MMU\n");
return -EINVAL;
}
/* we require greater support from the driver or
* filesystem - we ask it to tell us what memory to
* use */
if (!file->f_op->get_unmapped_area)
return -ENODEV;
}
else {
/* we read private files into memory we allocate */
if (!file->f_op->read)
return -ENODEV;
}
}
/* handle PROT_EXEC implication by PROT_READ */
if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
if (!(file && (file->f_vfsmnt->mnt_flags & MNT_NOEXEC)))
prot |= PROT_EXEC;
/* do simple checking here so the lower-level routines won't have
* to. we assume access permissions have been handled by the open
* of the memory object, so we don't do any here.
*/
vm_flags = calc_vm_flags(prot,flags) /* | mm->def_flags */
| VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
if (!membacked) {
/* share any file segment that's mapped read-only */
if (((flags & MAP_PRIVATE) && !(prot & PROT_WRITE) && file) ||
((flags & MAP_SHARED) && !(prot & PROT_WRITE) && file))
vm_flags |= VM_MAYSHARE;
/* refuse to let anyone share files with this process if it's being traced -
* otherwise breakpoints set in it may interfere with another untraced process
*/
if (current->ptrace & PT_PTRACED)
vm_flags &= ~(VM_SHARED | VM_MAYSHARE);
}
else {
/* permit sharing of character devices and ramfs files at any time for
* anything other than a privately writable mapping
*/
if (!(flags & MAP_PRIVATE) || !(prot & PROT_WRITE)) {
vm_flags |= VM_MAYSHARE;
if (flags & MAP_SHARED)
vm_flags |= VM_SHARED;
}
}
/* allow the security API to have its say */
ret = security_file_mmap(file, prot, flags);
if (ret)
return ret;
/* we're going to need to record the mapping if it works */
vml = kmalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
if (!vml)
goto error_getting_vml;
memset(vml, 0, sizeof(*vml));
down_write(&nommu_vma_sem);
/* if we want to share, we need to search for VMAs created by another
* mmap() call that overlap with our proposed mapping
* - we can only share with an exact match on most regular files
* - shared mappings on character devices and memory backed files are
* permitted to overlap inexactly as far as we are concerned for in
* these cases, sharing is handled in the driver or filesystem rather
* than here
*/
if (vm_flags & VM_MAYSHARE) {
unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
unsigned long vmpglen;
for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
vma = rb_entry(rb, struct vm_area_struct, vm_rb);
if (!(vma->vm_flags & VM_MAYSHARE))
continue;
/* search for overlapping mappings on the same file */
if (vma->vm_file->f_dentry->d_inode != file->f_dentry->d_inode)
continue;
if (vma->vm_pgoff >= pgoff + pglen)
continue;
vmpglen = (vma->vm_end - vma->vm_start + PAGE_SIZE - 1) >> PAGE_SHIFT;
if (pgoff >= vma->vm_pgoff + vmpglen)
continue;
/* handle inexact matches between mappings */
if (vmpglen != pglen || vma->vm_pgoff != pgoff) {
if (!membacked)
goto sharing_violation;
continue;
}
/* we've found a VMA we can share */
atomic_inc(&vma->vm_usage);
vml->vma = vma;
result = (void *) vma->vm_start;
goto shared;
}
}
vma = NULL;
/* obtain the address to map to. we verify (or select) it and ensure
* that it represents a valid section of the address space
* - this is the hook for quasi-memory character devices
*/
if (file && file->f_op->get_unmapped_area)
addr = file->f_op->get_unmapped_area(file, addr, len, pgoff, flags);
if (IS_ERR((void *) addr)) {
ret = addr;
goto error;
}
/* we're going to need a VMA struct as well */
vma = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
if (!vma)
goto error_getting_vma;
memset(vma, 0, sizeof(*vma));
INIT_LIST_HEAD(&vma->anon_vma_node);
atomic_set(&vma->vm_usage, 1);
if (file)
get_file(file);
vma->vm_file = file;
vma->vm_flags = vm_flags;
vma->vm_start = addr;
vma->vm_end = addr + len;
vma->vm_pgoff = pgoff;
vml->vma = vma;
/* determine the object being mapped and call the appropriate specific
* mapper.
*/
if (file) {
#ifdef MAGIC_ROM_PTR
/* First, try simpler routine designed to give us a ROM pointer. */
if (file->f_op->romptr && !(prot & PROT_WRITE)) {
ret = file->f_op->romptr(file, vma);
#ifdef DEBUG
printk("romptr mmap returned %d (st=%lx)\n",
ret, vma->vm_start);
#endif
result = (void *) vma->vm_start;
if (!ret)
goto done;
else if (ret != -ENOSYS)
goto error;
} else
#endif /* MAGIC_ROM_PTR */
/* Then try full mmap routine, which might return a RAM
* pointer, or do something truly complicated
*/
if (file->f_op->mmap) {
ret = file->f_op->mmap(file, vma);
#ifdef DEBUG
printk("f_op->mmap() returned %d (st=%lx)\n",
ret, vma->vm_start);
#endif
result = (void *) vma->vm_start;
if (!ret)
goto done;
else if (ret != -ENOSYS)
goto error;
} else {
ret = -ENODEV; /* No mapping operations defined */
goto error;
}
/* An ENOSYS error indicates that mmap isn't possible (as
* opposed to tried but failed) so we'll fall through to the
* copy. */
}
/* allocate some memory to hold the mapping
* - note that this may not return a page-aligned address if the object
* we're allocating is smaller than a page
*/
ret = -ENOMEM;
result = kmalloc(len, GFP_KERNEL);
if (!result) {
printk("Allocation of length %lu from process %d failed\n",
len, current->pid);
show_free_areas();
goto error;
}
vma->vm_start = (unsigned long) result;
vma->vm_end = vma->vm_start + len;
#ifdef WARN_ON_SLACK
if (len + WARN_ON_SLACK <= kobjsize(result))
printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
len, current->pid, kobjsize(result) - len);
#endif
if (file) {
mm_segment_t old_fs = get_fs();
loff_t fpos;
fpos = pgoff;
fpos <<= PAGE_SHIFT;
set_fs(KERNEL_DS);
ret = file->f_op->read(file, (char *) result, len, &fpos);
set_fs(old_fs);
if (ret < 0)
goto error2;
if (ret < len)
memset(result + ret, 0, len - ret);
} else {
memset(result, 0, len);
}
if (prot & PROT_EXEC)
flush_icache_range((unsigned long) result, (unsigned long) result + len);
done:
if (!(vma->vm_flags & VM_SHARED)) {
realalloc += kobjsize(result);
askedalloc += len;
}
realalloc += kobjsize(vma);
askedalloc += sizeof(*vma);
current->mm->total_vm += len >> PAGE_SHIFT;
add_nommu_vma(vma);
shared:
realalloc += kobjsize(vml);
askedalloc += sizeof(*vml);
vml->next = current->mm->context.vmlist;
current->mm->context.vmlist = vml;
up_write(&nommu_vma_sem);
#ifdef DEBUG
printk("do_mmap:\n");
show_process_blocks();
#endif
return (unsigned long) result;
error2:
kfree(result);
error:
up_write(&nommu_vma_sem);
kfree(vml);
if (vma) {
fput(vma->vm_file);
kfree(vma);
}
return ret;
sharing_violation:
up_write(&nommu_vma_sem);
printk("Attempt to share mismatched mappings\n");
kfree(vml);
return -EINVAL;
error_getting_vma:
up_write(&nommu_vma_sem);
kfree(vml);
printk("Allocation of vml for %lu byte allocation from process %d failed\n",
len, current->pid);
show_free_areas();
return -ENOMEM;
error_getting_vml:
printk("Allocation of vml for %lu byte allocation from process %d failed\n",
len, current->pid);
show_free_areas();
return -ENOMEM;
}
/*
* handle mapping disposal for uClinux
*/
static void put_vma(struct vm_area_struct *vma)
{
if (vma) {
down_write(&nommu_vma_sem);
if (atomic_dec_and_test(&vma->vm_usage)) {
delete_nommu_vma(vma);
if (vma->vm_ops && vma->vm_ops->close)
vma->vm_ops->close(vma);
/* IO memory and memory shared directly out of the pagecache from
* ramfs/tmpfs mustn't be released here */
if (!(vma->vm_flags & (VM_IO | VM_SHARED)) && vma->vm_start) {
realalloc -= kobjsize((void *) vma->vm_start);
askedalloc -= vma->vm_end - vma->vm_start;
kfree((void *) vma->vm_start);
}
realalloc -= kobjsize(vma);
askedalloc -= sizeof(*vma);
if (vma->vm_file)
fput(vma->vm_file);
kfree(vma);
}
up_write(&nommu_vma_sem);
}
}
int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
{
struct vm_list_struct *vml, **parent;
unsigned long end = addr + len;
#ifdef MAGIC_ROM_PTR
/* For efficiency's sake, if the pointer is obviously in ROM,
don't bother walking the lists to free it */
if (is_in_rom(addr))
return 0;
#endif
#ifdef DEBUG
printk("do_munmap:\n");
#endif
for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next)
if ((*parent)->vma->vm_start == addr &&
(*parent)->vma->vm_end == end)
goto found;
printk("munmap of non-mmaped memory by process %d (%s): %p\n",
current->pid, current->comm, (void *) addr);
return -EINVAL;
found:
vml = *parent;
put_vma(vml->vma);
*parent = vml->next;
realalloc -= kobjsize(vml);
askedalloc -= sizeof(*vml);
kfree(vml);
mm->total_vm -= len >> PAGE_SHIFT;
#ifdef DEBUG
show_process_blocks();
#endif
return 0;
}
/* Release all mmaps. */
void exit_mmap(struct mm_struct * mm)
{
struct vm_list_struct *tmp;
if (mm) {
#ifdef DEBUG
printk("Exit_mmap:\n");
#endif
mm->total_vm = 0;
while ((tmp = mm->context.vmlist)) {
mm->context.vmlist = tmp->next;
put_vma(tmp->vma);
realalloc -= kobjsize(tmp);
askedalloc -= sizeof(*tmp);
kfree(tmp);
}
#ifdef DEBUG
show_process_blocks();
#endif
}
}
asmlinkage long sys_munmap(unsigned long addr, size_t len)
{
int ret;
struct mm_struct *mm = current->mm;
down_write(&mm->mmap_sem);
ret = do_munmap(mm, addr, len);
up_write(&mm->mmap_sem);
return ret;
}
unsigned long do_brk(unsigned long addr, unsigned long len)
{
return -ENOMEM;
}
/*
* Expand (or shrink) an existing mapping, potentially moving it at the
* same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
*
* MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
* This option implies MREMAP_MAYMOVE.
*
* on uClinux, we only permit changing a mapping's size, and only as long as it stays within the
* hole allocated by the kmalloc() call in do_mmap_pgoff() and the block is not shareable
*/
unsigned long do_mremap(unsigned long addr,
unsigned long old_len, unsigned long new_len,
unsigned long flags, unsigned long new_addr)
{
struct vm_list_struct *vml = NULL;
/* insanity checks first */
if (new_len == 0)
return (unsigned long) -EINVAL;
if (flags & MREMAP_FIXED && new_addr != addr)
return (unsigned long) -EINVAL;
for (vml = current->mm->context.vmlist; vml; vml = vml->next)
if (vml->vma->vm_start == addr)
goto found;
return (unsigned long) -EINVAL;
found:
if (vml->vma->vm_end != vml->vma->vm_start + old_len)
return (unsigned long) -EFAULT;
if (vml->vma->vm_flags & VM_MAYSHARE)
return (unsigned long) -EPERM;
if (new_len > kobjsize((void *) addr))
return (unsigned long) -ENOMEM;
/* all checks complete - do it */
vml->vma->vm_end = vml->vma->vm_start + new_len;
askedalloc -= old_len;
askedalloc += new_len;
return vml->vma->vm_start;
}
/*
* Look up the first VMA which satisfies addr < vm_end, NULL if none
*/
struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
{
struct vm_list_struct *vml;
for (vml = mm->context.vmlist; vml; vml = vml->next)
if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end)
return vml->vma;
return NULL;
}
EXPORT_SYMBOL(find_vma);
struct page * follow_page(struct mm_struct *mm, unsigned long addr, int write)
{
return NULL;
}
struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
{
return NULL;
}
int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
unsigned long to, unsigned long size, pgprot_t prot)
{
return -EPERM;
}
void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
{
}
unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
return -ENOMEM;
}
void arch_unmap_area(struct vm_area_struct *area)
{
}
void update_mem_hiwater(void)
{
struct task_struct *tsk = current;
if (likely(tsk->mm)) {
if (tsk->mm->hiwater_rss < tsk->mm->rss)
tsk->mm->hiwater_rss = tsk->mm->rss;
if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
tsk->mm->hiwater_vm = tsk->mm->total_vm;
}
}
void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen,
int even_cows)
{
}
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