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/*
* The kernel's access_process_vm is not exported in kernel.org kernels, although
* some distros export it on some architectures. To workaround this inconsistency,
* we copied and pasted it here. Fortunately, everything it calls is exported.
*/
#include <linux/pagemap.h>
#include <asm/cacheflush.h>
static int
__access_process_vm_(struct task_struct *tsk, unsigned long addr, void *buf,
int len, int write,
void (*writer)(struct vm_area_struct *vma,
struct page *page, unsigned long vaddr,
void *dst, void *src, int len),
void (*reader)(struct vm_area_struct *vma,
struct page *page, unsigned long vaddr,
void *dst, void *src, int len)
)
{
struct mm_struct *mm;
struct vm_area_struct *vma;
struct page *page;
void *old_buf = buf;
mm = get_task_mm(tsk);
if (!mm)
return 0;
down_read(&mm->mmap_sem);
/* ignore errors, just check how much was sucessfully transfered */
while (len) {
int bytes, ret, offset;
void *maddr;
ret = get_user_pages(tsk, mm, addr, 1,
write, 1, &page, &vma);
if (ret <= 0)
break;
bytes = len;
offset = addr & (PAGE_SIZE-1);
if (bytes > PAGE_SIZE-offset)
bytes = PAGE_SIZE-offset;
maddr = kmap(page);
if (write) {
writer(vma, page, addr,
maddr + offset, buf, bytes);
set_page_dirty_lock(page);
} else {
reader(vma, page, addr,
buf, maddr + offset, bytes);
}
kunmap(page);
page_cache_release(page);
len -= bytes;
buf += bytes;
addr += bytes;
}
up_read(&mm->mmap_sem);
mmput(mm);
return buf - old_buf;
}
static void
copy_to_user_page_ (struct vm_area_struct *vma, struct page *page, unsigned long vaddr,
void *dst, void *src, int len)
{
copy_to_user_page (vma, page, vaddr, dst, src, len);
}
static void
copy_from_user_page_ (struct vm_area_struct *vma, struct page *page, unsigned long vaddr,
void *dst, void *src, int len)
{
copy_from_user_page (vma, page, vaddr, dst, src, len);
}
static int __access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
{
return __access_process_vm_(tsk, addr, buf, len, write, copy_to_user_page_, copy_from_user_page_);
}
/* This simpler version does not flush the caches. */
static void
copy_to_user_page_noflush (struct vm_area_struct *vma, struct page *page, unsigned long vaddr,
void *dst, void *src, int len)
{
memcpy (dst, src, len);
}
static void
copy_from_user_page_noflush (struct vm_area_struct *vma, struct page *page, unsigned long vaddr,
void *dst, void *src, int len)
{
memcpy (dst, src, len);
}
static int __access_process_vm_noflush(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
{
return __access_process_vm_(tsk, addr, buf, len, write, copy_to_user_page_noflush, copy_from_user_page_noflush);
}
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