aboutsummaryrefslogtreecommitdiffstats
path: root/mm/hugetlb.c
diff options
context:
space:
mode:
authorZhang, Yanmin <yanmin_zhang@linux.intel.com>2006-03-22 03:08:50 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-22 10:54:03 -0500
commit8f860591ffb29738cf5539b6fbf27f50dcdeb380 (patch)
tree4265e45c4a79d86a16cd5175a836e8c531be8117 /mm/hugetlb.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/hugetlb.c')
-rw-r--r--mm/hugetlb.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 20117a4b8ab..783098f6cf8 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -565,3 +565,32 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
565 565
566 return i; 566 return i;
567} 567}
568
569void hugetlb_change_protection(struct vm_area_struct *vma,
570 unsigned long address, unsigned long end, pgprot_t newprot)
571{
572 struct mm_struct *mm = vma->vm_mm;
573 unsigned long start = address;
574 pte_t *ptep;
575 pte_t pte;
576
577 BUG_ON(address >= end);
578 flush_cache_range(vma, address, end);
579
580 spin_lock(&mm->page_table_lock);
581 for (; address < end; address += HPAGE_SIZE) {
582 ptep = huge_pte_offset(mm, address);
583 if (!ptep)
584 continue;
585 if (!pte_none(*ptep)) {
586 pte = huge_ptep_get_and_clear(mm, address, ptep);
587 pte = pte_mkhuge(pte_modify(pte, newprot));
588 set_huge_pte_at(mm, address, ptep, pte);
589 lazy_mmu_prot_update(pte);
590 }
591 }
592 spin_unlock(&mm->page_table_lock);
593
594 flush_tlb_range(vma, start, end);
595}
596