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nommu.c
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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).
*
* See Documentation/nommu-mmap.txt
*
* Copyright (c) 2004-2005 David Howells <[email protected]>
* Copyright (c) 2000-2003 David McCullough <[email protected]>
* Copyright (c) 2000-2001 D Jeff Dionne <[email protected]>
* Copyright (c) 2002 Greg Ungerer <[email protected]>
*/
#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(mem_map);
EXPORT_SYMBOL(__vm_enough_memory);
/* 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 = {
};
EXPORT_SYMBOL(vfree);
EXPORT_SYMBOL(vmalloc_to_page);
EXPORT_SYMBOL(vmalloc_32);
EXPORT_SYMBOL(vmap);
EXPORT_SYMBOL(vunmap);
/*
* 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);
}
EXPORT_SYMBOL(get_user_pages);
DEFINE_RWLOCK(vmlist_lock);
struct vm_struct *vmlist;
void vfree(void *addr)
{
kfree(addr);
}
void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
{
/*
* kmalloc doesn't like __GFP_HIGHMEM for some reason
*/
return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__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);
}
EXPORT_SYMBOL(vmalloc);
void *vmalloc_node(unsigned long size, int node)
{
return vmalloc(size);
}
EXPORT_SYMBOL(vmalloc_node);
/*
* 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;
}
#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);
}
/*
* determine whether a mapping should be permitted and, if so, what sort of
* mapping we're capable of supporting
*/
static int validate_mmap_request(struct file *file,
unsigned long addr,
unsigned long len,
unsigned long prot,
unsigned long flags,
unsigned long pgoff,
unsigned long *_capabilities)
{
unsigned long capabilities;
unsigned long reqprot = prot;
int ret;
/* 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 ((flags & MAP_TYPE) != MAP_PRIVATE &&
(flags & MAP_TYPE) != MAP_SHARED)
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;
if (file) {
/* validate file mapping requests */
struct address_space *mapping;
/* files must support mmap */
if (!file->f_op || !file->f_op->mmap)
return -ENODEV;
/* 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
*/
mapping = file->f_mapping;
if (!mapping)
mapping = file->f_dentry->d_inode->i_mapping;
capabilities = 0;
if (mapping && mapping->backing_dev_info)
capabilities = mapping->backing_dev_info->capabilities;
if (!capabilities) {
/* no explicit capabilities set, so assume some
* defaults */
switch (file->f_dentry->d_inode->i_mode & S_IFMT) {
case S_IFREG:
case S_IFBLK:
capabilities = BDI_CAP_MAP_COPY;
break;
case S_IFCHR:
capabilities =
BDI_CAP_MAP_DIRECT |
BDI_CAP_READ_MAP |
BDI_CAP_WRITE_MAP;
break;
default:
return -EINVAL;
}
}
/* eliminate any capabilities that we can't support on this
* device */
if (!file->f_op->get_unmapped_area)
capabilities &= ~BDI_CAP_MAP_DIRECT;
if (!file->f_op->read)
capabilities &= ~BDI_CAP_MAP_COPY;
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 (!(capabilities & BDI_CAP_MAP_DIRECT))
return -ENODEV;
if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
) {
printk("MAP_SHARED not completely supported on !MMU\n");
return -EINVAL;
}
/* we mustn't privatise shared mappings */
capabilities &= ~BDI_CAP_MAP_COPY;
}
else {
/* we're going to read the file into private memory we
* allocate */
if (!(capabilities & BDI_CAP_MAP_COPY))
return -ENODEV;
/* we don't permit a private writable mapping to be
* shared with the backing device */
if (prot & PROT_WRITE)
capabilities &= ~BDI_CAP_MAP_DIRECT;
}
/* handle executable mappings and implied executable
* mappings */
if (file->f_vfsmnt->mnt_flags & MNT_NOEXEC) {
if (prot & PROT_EXEC)
return -EPERM;
}
else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
/* handle implication of PROT_EXEC by PROT_READ */
if (current->personality & READ_IMPLIES_EXEC) {
if (capabilities & BDI_CAP_EXEC_MAP)
prot |= PROT_EXEC;
}
}
else if ((prot & PROT_READ) &&
(prot & PROT_EXEC) &&
!(capabilities & BDI_CAP_EXEC_MAP)
) {
/* backing file is not executable, try to copy */
capabilities &= ~BDI_CAP_MAP_DIRECT;
}
}
else {
/* anonymous mappings are always memory backed and can be
* privately mapped
*/
capabilities = BDI_CAP_MAP_COPY;
/* handle PROT_EXEC implication by PROT_READ */
if ((prot & PROT_READ) &&
(current->personality & READ_IMPLIES_EXEC))
prot |= PROT_EXEC;
}
/* allow the security API to have its say */
ret = security_file_mmap(file, reqprot, prot, flags);
if (ret < 0)
return ret;
/* looks okay */
*_capabilities = capabilities;
return 0;
}
/*
* we've determined that we can make the mapping, now translate what we
* now know into VMA flags
*/
static unsigned long determine_vm_flags(struct file *file,
unsigned long prot,
unsigned long flags,
unsigned long capabilities)
{
unsigned long vm_flags;
vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
/* vm_flags |= mm->def_flags; */
if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
/* attempt to share read-only copies of mapped file chunks */
if (file && !(prot & PROT_WRITE))
vm_flags |= VM_MAYSHARE;
}
else {
/* overlay a shareable mapping on the backing device or inode
* if possible - used for chardevs, ramfs/tmpfs/shmfs and
* romfs/cramfs */
if (flags & MAP_SHARED)
vm_flags |= VM_MAYSHARE | VM_SHARED;
else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
vm_flags |= VM_MAYSHARE;
}
/* refuse to let anyone share private mappings with this process if
* it's being traced - otherwise breakpoints set in it may interfere
* with another untraced process
*/
if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
vm_flags &= ~VM_MAYSHARE;
return vm_flags;
}
/*
* set up a shared mapping on a file
*/
static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
{
int ret;
ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
if (ret != -ENOSYS)
return ret;
/* getting an ENOSYS error indicates that direct mmap isn't
* possible (as opposed to tried but failed) so we'll fall
* through to making a private copy of the data and mapping
* that if we can */
return -ENODEV;
}
/*
* set up a private mapping or an anonymous shared mapping
*/
static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
{
void *base;
int ret;
/* invoke the file's mapping function so that it can keep track of
* shared mappings on devices or memory
* - VM_MAYSHARE will be set if it may attempt to share
*/
if (vma->vm_file) {
ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
if (ret != -ENOSYS) {
/* shouldn't return success if we're not sharing */
BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
return ret; /* success or a real error */
}
/* getting an ENOSYS error indicates that direct mmap isn't
* possible (as opposed to tried but failed) so we'll try to
* make a private copy of the data and map that instead */
}
/* 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
*/
base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
if (!base)
goto enomem;
vma->vm_start = (unsigned long) base;
vma->vm_end = vma->vm_start + len;
vma->vm_flags |= VM_MAPPED_COPY;
#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 (vma->vm_file) {
/* read the contents of a file into the copy */
mm_segment_t old_fs;
loff_t fpos;
fpos = vma->vm_pgoff;
fpos <<= PAGE_SHIFT;
old_fs = get_fs();
set_fs(KERNEL_DS);
ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
set_fs(old_fs);
if (ret < 0)
goto error_free;
/* clear the last little bit */
if (ret < len)
memset(base + ret, 0, len - ret);
} else {
/* if it's an anonymous mapping, then just clear it */
memset(base, 0, len);
}
return 0;
error_free:
kfree(base);
vma->vm_start = 0;
return ret;
enomem:
printk("Allocation of length %lu from process %d failed\n",
len, current->pid);
show_free_areas();
return -ENOMEM;
}
/*
* 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 long capabilities, vm_flags;
void *result;
int ret;
/* decide whether we should attempt the mapping, and if so what sort of
* mapping */
ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
&capabilities);
if (ret < 0)
return ret;
/* we've determined that we can make the mapping, now translate what we
* now know into VMA flags */
vm_flags = determine_vm_flags(file, prot, flags, capabilities);
/* 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 check for VMAs created by other
* mmap() calls 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;
vmpglen >>= PAGE_SHIFT;
if (pgoff >= vma->vm_pgoff + vmpglen)
continue;
/* handle inexactly overlapping matches between mappings */
if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
if (!(capabilities & BDI_CAP_MAP_DIRECT))
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 at which to make a shared mapping
* - this is the hook for quasi-memory character devices to
* tell us the location of a shared mapping
*/
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;
if (ret != (unsigned long) -ENOSYS)
goto error;
/* the driver refused to tell us where to site
* the mapping so we'll have to attempt to copy
* it */
ret = (unsigned long) -ENODEV;
if (!(capabilities & BDI_CAP_MAP_COPY))
goto error;
capabilities &= ~BDI_CAP_MAP_DIRECT;
}
}
}
/* 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;
/* set up the mapping */
if (file && vma->vm_flags & VM_SHARED)
ret = do_mmap_shared_file(vma, len);
else
ret = do_mmap_private(vma, len);
if (ret < 0)
goto error;
/* okay... we have a mapping; now we have to register it */
result = (void *) vma->vm_start;
if (vma->vm_flags & VM_MAPPED_COPY) {
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);
if (prot & PROT_EXEC)
flush_icache_range((unsigned long) result,
(unsigned long) result + len);
#ifdef DEBUG
printk("do_mmap:\n");
show_process_blocks();
#endif
return (unsigned long) 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 vma 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_MAPPED_COPY) {
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 DEBUG
printk("do_munmap:\n");
#endif
for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next)
if ((*parent)->vma->vm_start == addr &&
((len == 0) || ((*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);
update_hiwater_vm(mm);
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