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authorDavid Gibson <david@gibson.dropbear.id.au>2005-11-24 14:16:15 +1100
committerPaul Mackerras <paulus@samba.org>2006-01-09 14:50:28 +1100
commit456752f7505ef8f580ffd157558e661da2767d99 (patch)
tree8854e9dd2d21ac440f691dd16881e596db61896b /arch
parent706e6b2caf285d3eb056c2847b7c53ae823e8a87 (diff)
[PATCH] powerpc: Make hugepage mappings respect hint addresses
Currently, the powerpc version of hugetlb_get_unmapped_area() entirely ignores the hint address. The only way to get a hugepage mapping at a specified address is with MAP_FIXED, in which case there's no way (short of parsing /proc/self/maps) for userspace to tell if it will clobber an existing mapping. This is inconvenient, so the patch below makes hugepage mappings use the given hint address if possible. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/mm/hugetlbpage.c43
1 files changed, 39 insertions, 4 deletions
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 54131b877da..f6fe3eaf87a 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -549,6 +549,17 @@ fail:
return addr;
}
+static int htlb_check_hinted_area(unsigned long addr, unsigned long len)
+{
+ struct vm_area_struct *vma;
+
+ vma = find_vma(current->mm, addr);
+ if (!vma || ((addr + len) <= vma->vm_start))
+ return 0;
+
+ return -ENOMEM;
+}
+
static unsigned long htlb_get_low_area(unsigned long len, u16 segmask)
{
unsigned long addr = 0;
@@ -609,6 +620,7 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
{
int lastshift;
u16 areamask, curareas;
+ struct vm_area_struct *vma;
if (HPAGE_SHIFT == 0)
return -EINVAL;
@@ -618,15 +630,28 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
if (!cpu_has_feature(CPU_FTR_16M_PAGE))
return -EINVAL;
+ /* Paranoia, caller should have dealt with this */
+ BUG_ON((addr + len) < addr);
+
if (test_thread_flag(TIF_32BIT)) {
+ /* Paranoia, caller should have dealt with this */
+ BUG_ON((addr + len) > 0x100000000UL);
+
curareas = current->mm->context.low_htlb_areas;
- /* First see if we can do the mapping in the existing
- * low areas */
+ /* First see if we can use the hint address */
+ if (addr && (htlb_check_hinted_area(addr, len) == 0)) {
+ areamask = LOW_ESID_MASK(addr, len);
+ if (open_low_hpage_areas(current->mm, areamask) == 0)
+ return addr;
+ }
+
+ /* Next see if we can map in the existing low areas */
addr = htlb_get_low_area(len, curareas);
if (addr != -ENOMEM)
return addr;
+ /* Finally go looking for areas to open */
lastshift = 0;
for (areamask = LOW_ESID_MASK(0x100000000UL-len, len);
! lastshift; areamask >>=1) {
@@ -641,12 +666,22 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
} else {
curareas = current->mm->context.high_htlb_areas;
- /* First see if we can do the mapping in the existing
- * high areas */
+ /* First see if we can use the hint address */
+ /* We discourage 64-bit processes from doing hugepage
+ * mappings below 4GB (must use MAP_FIXED) */
+ if ((addr >= 0x100000000UL)
+ && (htlb_check_hinted_area(addr, len) == 0)) {
+ areamask = HTLB_AREA_MASK(addr, len);
+ if (open_high_hpage_areas(current->mm, areamask) == 0)
+ return addr;
+ }
+
+ /* Next see if we can map in the existing high areas */
addr = htlb_get_high_area(len, curareas);
if (addr != -ENOMEM)
return addr;
+ /* Finally go looking for areas to open */
lastshift = 0;
for (areamask = HTLB_AREA_MASK(TASK_SIZE_USER64-len, len);
! lastshift; areamask >>=1) {