unsigned long
arch_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long start_addr;
unsigned long begin, end;
if (flags & MAP_FIXED)
return addr;
find_start_end(flags, &begin, &end);
if (len > end)
return -ENOMEM;
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (end - len >= addr &&
(!vma || addr + len <= vma->vm_start))
return addr;
}
if (((flags & MAP_32BIT) || test_thread_flag(TIF_ADDR32))
&& len <= mm->cached_hole_size) {
mm->cached_hole_size = 0;
mm->free_area_cache = begin;
}
addr = mm->free_area_cache;
if (addr < begin)
addr = begin;
start_addr = addr;
full_search:
addr = align_addr(addr, filp, 0);
for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
if (end - len < addr) {
if (start_addr != begin) {
start_addr = addr = begin;
mm->cached_hole_size = 0;
goto full_search;
}
return -ENOMEM;
}
if (!vma || addr + len <= vma->vm_start) {
mm->free_area_cache = addr + len;
return addr;
}
if (addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
addr = vma->vm_end;
addr = align_addr(addr, filp, 0);
}
}
void *aom_memalign(size_t align, size_t size) {
void *addr, *x = NULL;
addr = malloc(size + align - 1 + ADDRESS_STORAGE_SIZE);
if (addr) {
x = align_addr((unsigned char *)addr + ADDRESS_STORAGE_SIZE, (int)align);
/* save the actual malloc address */
((size_t *)x)[-1] = (size_t)addr;
}
return x;
}
/* Put the vdso above the (randomized) stack with another randomized offset.
This way there is no hole in the middle of address space.
To save memory make sure it is still in the same PTE as the stack top.
This doesn't give that many random bits */
static unsigned long vdso_addr(unsigned long start, unsigned len)
{
unsigned long addr, end;
unsigned offset;
end = (start + PMD_SIZE - 1) & PMD_MASK;
if (end >= TASK_SIZE_MAX)
end = TASK_SIZE_MAX;
end -= len;
/* This loses some more bits than a modulo, but is cheaper */
offset = get_random_int() & (PTRS_PER_PTE - 1);
addr = start + (offset << PAGE_SHIFT);
if (addr >= end)
addr = end;
/*
* page-align it here so that get_unmapped_area doesn't
* align it wrongfully again to the next page. addr can come in 4K
* unaligned here as a result of stack start randomization.
*/
addr = PAGE_ALIGN(addr);
addr = align_addr(addr, NULL, ALIGN_VDSO);
return addr;
}
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr = addr0, start_addr;
/* requested length too big for entire address space */
if (len > TASK_SIZE)
return -ENOMEM;
if (flags & MAP_FIXED)
return addr;
/* for MAP_32BIT mappings we force the legact mmap base */
if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT))
goto bottomup;
/* requesting a specific address */
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr &&
(!vma || addr + len <= vma->vm_start))
return addr;
}
/* check if free_area_cache is useful for us */
if (len <= mm->cached_hole_size) {
mm->cached_hole_size = 0;
mm->free_area_cache = mm->mmap_base;
}
try_again:
/* either no address requested or can't fit in requested address hole */
start_addr = addr = mm->free_area_cache;
if (addr < len)
goto fail;
addr -= len;
do {
addr = align_addr(addr, filp, ALIGN_TOPDOWN);
/*
* Lookup failure means no vma is above this address,
* else if new region fits below vma->vm_start,
* return with success:
*/
vma = find_vma(mm, addr);
if (!vma || addr+len <= vma->vm_start)
/* remember the address as a hint for next time */
return mm->free_area_cache = addr;
/* remember the largest hole we saw so far */
if (addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
/* try just below the current vma->vm_start */
addr = vma->vm_start-len;
} while (len < vma->vm_start);
fail:
/*
* if hint left us with no space for the requested
* mapping then try again:
*/
if (start_addr != mm->mmap_base) {
mm->free_area_cache = mm->mmap_base;
mm->cached_hole_size = 0;
goto try_again;
}
bottomup:
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
mm->cached_hole_size = ~0UL;
mm->free_area_cache = TASK_UNMAPPED_BASE;
addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
/*
* Restore the topdown base:
*/
mm->free_area_cache = mm->mmap_base;
mm->cached_hole_size = ~0UL;
return addr;
}
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr = addr0, start_addr;
if (len > TASK_SIZE)
return -ENOMEM;
if (flags & MAP_FIXED)
return addr;
if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT))
goto bottomup;
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr &&
(!vma || addr + len <= vma->vm_start))
return addr;
}
if (len <= mm->cached_hole_size) {
mm->cached_hole_size = 0;
mm->free_area_cache = mm->mmap_base;
}
try_again:
start_addr = addr = mm->free_area_cache;
if (addr < len)
goto fail;
addr -= len;
do {
addr = align_addr(addr, filp, ALIGN_TOPDOWN);
vma = find_vma(mm, addr);
if (!vma || addr+len <= vma->vm_start)
return mm->free_area_cache = addr;
if (addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
addr = vma->vm_start-len;
} while (len < vma->vm_start);
fail:
if (start_addr != mm->mmap_base) {
mm->free_area_cache = mm->mmap_base;
mm->cached_hole_size = 0;
goto try_again;
}
bottomup:
mm->cached_hole_size = ~0UL;
mm->free_area_cache = TASK_UNMAPPED_BASE;
addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
mm->free_area_cache = mm->mmap_base;
mm->cached_hole_size = ~0UL;
return addr;
}
unsigned long
arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
const unsigned long len, const unsigned long pgoff,
const unsigned long flags)
{
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr = addr0;
unsigned int unmap_factor = sysctl_unmap_area_factor;
int firsttime = 1;
/* requested length too big for entire address space */
if (len > TASK_SIZE)
return -ENOMEM;
if (flags & MAP_FIXED)
return addr;
/* for MAP_32BIT mappings we force the legact mmap base */
if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT))
goto bottomup;
/* requesting a specific address */
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (TASK_SIZE - len >= addr &&
(!vma || addr + len <= vma->vm_start) &&
(addr >= mmap_min_addr))
return addr;
}
/* check if free_area_cache is useful for us */
if (len <= mm->cached_hole_size && !unmap_factor) {
mm->cached_hole_size = 0;
mm->free_area_cache = mm->mmap_base;
}
again:
/* either no address requested or can't fit in requested address hole */
addr = mm->free_area_cache;
/* make sure it can fit in the remaining address space */
if (addr > len) {
unsigned long tmp_addr = align_addr(addr - len, filp,
ALIGN_TOPDOWN);
vma = find_vma(mm, tmp_addr);
if ((!vma || tmp_addr + len <= vma->vm_start) &&
(tmp_addr >= mmap_min_addr))
/* remember the address as a hint for next time */
return mm->free_area_cache = tmp_addr;
}
if (mm->mmap_base < len)
goto bottomup;
if (likely(!unmap_factor))
addr = mm->mmap_base-len;
do {
addr = align_addr(addr, filp, ALIGN_TOPDOWN);
/*
* Lookup failure means no vma is above this address,
* else if new region fits below vma->vm_start,
* return with success:
*/
vma = find_vma(mm, addr);
if (!vma || addr+len <= vma->vm_start) {
/* we hit the bottom, stop this search */
if (addr < mmap_min_addr)
break;
/* remember the address as a hint for next time */
return mm->free_area_cache = addr;
}
/* remember the largest hole we saw so far */
if (!unmap_factor &&
addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
/* try just below the current vma->vm_start */
addr = vma->vm_start-len;
} while (len < vma->vm_start);
/*
* Using the next-fit algorithm, it is possible we started
* searching below usable address space holes. Go back to the
* top and start over.
*/
if (unmap_factor && firsttime) {
mm->free_area_cache = mm->mmap_base;
mm->cached_hole_size = 0;
firsttime = 0;
goto again;
}
bottomup:
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
if (likely(!unmap_factor))
mm->cached_hole_size = ~0UL;
mm->free_area_cache = TASK_UNMAPPED_BASE;
addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
/*
* Restore the topdown base:
*/
mm->free_area_cache = mm->mmap_base;
if (likely(!unmap_factor))
mm->cached_hole_size = ~0UL;
return addr;
}
unsigned long
arch_get_unmapped_area(struct file *filp, unsigned long addr,
unsigned long len, unsigned long pgoff, unsigned long flags)
{
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long start_addr;
unsigned long begin, end;
unsigned int unmap_factor = sysctl_unmap_area_factor;
if (flags & MAP_FIXED)
return addr;
find_start_end(flags, &begin, &end);
if (len > end)
return -ENOMEM;
if (addr) {
addr = PAGE_ALIGN(addr);
vma = find_vma(mm, addr);
if (end - len >= addr &&
(!vma || addr + len <= vma->vm_start) &&
(addr >= mmap_min_addr))
return addr;
}
if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))) {
if (!unmap_factor && len <= mm->cached_hole_size)
mm->cached_hole_size = 0;
mm->free_area_cache = begin;
}
addr = mm->free_area_cache;
if (addr < begin)
addr = begin;
start_addr = addr;
full_search:
addr = align_addr(addr, filp, 0);
for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
/* At this point: (!vma || addr < vma->vm_end). */
if (end - len < addr) {
/*
* Start a new search - just in case we missed
* some holes.
*/
if (start_addr != begin) {
start_addr = addr = begin;
if (likely(!unmap_factor))
mm->cached_hole_size = 0;
goto full_search;
}
return -ENOMEM;
}
if (!vma || addr + len <= vma->vm_start) {
/*
* Remember the place where we stopped the search:
*/
mm->free_area_cache = addr + len;
return addr;
}
if (!unmap_factor &&
addr + mm->cached_hole_size < vma->vm_start)
mm->cached_hole_size = vma->vm_start - addr;
addr = vma->vm_end;
addr = align_addr(addr, filp, 0);
}
}
