asmlinkage unsigned long
ia64_mremap (unsigned long addr, unsigned long old_len, unsigned long new_len, unsigned long flags,
unsigned long new_addr)
{
addr = sys_mremap(addr, old_len, new_len, flags, new_addr);
if (!IS_ERR((void *) addr))
force_successful_syscall_return();
return addr;
}
static int vdso_remap(char *who, unsigned long from, unsigned long to, size_t size)
{
unsigned long addr;
pr_debug("Remap %s %lx -> %lx\n", who, from, to);
addr = sys_mremap(from, size, size, MREMAP_MAYMOVE | MREMAP_FIXED, to);
if (addr != to) {
pr_err("Unable to remap %lx -> %lx %lx\n",
from, to, addr);
return -1;
}
return 0;
}
static int vma_remap(unsigned long src, unsigned long dst, unsigned long len)
{
unsigned long guard = 0, tmp;
pr_info("Remap %lx->%lx len %lx\n", src, dst, len);
if (src - dst < len)
guard = dst;
else if (dst - src < len)
guard = dst + len - PAGE_SIZE;
if (src == dst)
return 0;
if (guard != 0) {
/*
* mremap() returns an error if a target and source vma-s are
* overlapped. In this case the source vma are remapped in
* a temporary place and then remapped to the target address.
* Here is one hack to find non-ovelapped temporary place.
*
* 1. initial placement. We need to move src -> tgt.
* | |+++++src+++++|
* |-----tgt-----| |
*
* 2. map a guard page at the non-ovelapped border of a target vma.
* | |+++++src+++++|
* |G|----tgt----| |
*
* 3. remap src to any other place.
* G prevents src from being remaped on tgt again
* | |-------------| -> |+++++src+++++|
* |G|---tgt-----| |
*
* 4. remap src to tgt, no overlapping any longer
* |+++++src+++++| <---- |-------------|
* |G|---tgt-----| |
*/
unsigned long addr;
/* Map guard page (step 2) */
tmp = sys_mmap((void *) guard, PAGE_SIZE, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
if (tmp != guard) {
pr_err("Unable to map a guard page %lx (%lx)\n", guard, tmp);
return -1;
}
/* Move src to non-overlapping place (step 3) */
addr = sys_mmap(NULL, len, PROT_NONE,
MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
if (addr == (unsigned long) MAP_FAILED) {
pr_err("Unable to reserve memory (%lx)\n", addr);
return -1;
}
tmp = sys_mremap(src, len, len,
MREMAP_MAYMOVE | MREMAP_FIXED, addr);
if (tmp != addr) {
pr_err("Unable to remap %lx -> %lx (%lx)\n", src, addr, tmp);
return -1;
}
src = addr;
}
tmp = sys_mremap(src, len, len, MREMAP_MAYMOVE | MREMAP_FIXED, dst);
if (tmp != dst) {
pr_err("Unable to remap %lx -> %lx\n", src, dst);
return -1;
}
return 0;
}
