path: root/mm/mprotect.c
diff options
authorZhang, Yanmin <yanmin_zhang@linux.intel.com>2006-03-22 00:08:50 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-22 07:54:03 -0800
commit8f860591ffb29738cf5539b6fbf27f50dcdeb380 (patch)
tree4265e45c4a79d86a16cd5175a836e8c531be8117 /mm/mprotect.c
parentaed75ff3caafce404d9be7f0c088716375be5279 (diff)
[PATCH] Enable mprotect on huge pages
2.6.16-rc3 uses hugetlb on-demand paging, but it doesn_t support hugetlb mprotect. From: David Gibson <david@gibson.dropbear.id.au> Remove a test from the mprotect() path which checks that the mprotect()ed range on a hugepage VMA is hugepage aligned (yes, really, the sense of is_aligned_hugepage_range() is the opposite of what you'd guess :-/). In fact, we don't need this test. If the given addresses match the beginning/end of a hugepage VMA they must already be suitably aligned. If they don't, then mprotect_fixup() will attempt to split the VMA. The very first test in split_vma() will check for a badly aligned address on a hugepage VMA and return -EINVAL if necessary. From: "Chen, Kenneth W" <kenneth.w.chen@intel.com> On i386 and x86-64, pte flag _PAGE_PSE collides with _PAGE_PROTNONE. The identify of hugetlb pte is lost when changing page protection via mprotect. A page fault occurs later will trigger a bug check in huge_pte_alloc(). The fix is to always make new pte a hugetlb pte and also to clean up legacy code where _PAGE_PRESENT is forced on in the pre-faulting day. Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: "David S. Miller" <davem@davemloft.net> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/mprotect.c')
1 files changed, 5 insertions, 7 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 653b8571c1e..4c14d4289b6 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -124,7 +124,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
* a MAP_NORESERVE private mapping to writable will now reserve.
if (newflags & VM_WRITE) {
+ if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_SHARED))) {
charged = nrpages;
if (security_vm_enough_memory(charged))
return -ENOMEM;
@@ -166,7 +166,10 @@ success:
vma->vm_flags = newflags;
vma->vm_page_prot = newprot;
- change_protection(vma, start, end, newprot);
+ if (is_vm_hugetlb_page(vma))
+ hugetlb_change_protection(vma, start, end, newprot);
+ else
+ change_protection(vma, start, end, newprot);
vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
vm_stat_account(mm, newflags, vma->vm_file, nrpages);
return 0;
@@ -240,11 +243,6 @@ sys_mprotect(unsigned long start, size_t len, unsigned long prot)
/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
- if (is_vm_hugetlb_page(vma)) {
- error = -EACCES;
- goto out;
- }
newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
/* newflags >> 4 shift VM_MAY% in place of VM_% */