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authorHugh Dickins <hugh@veritas.com>2005-04-19 13:29:19 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org.(none)>2005-04-19 13:29:19 -0700
commite2cdef8c847b480529b7e26991926aab4be008e6 (patch)
treeb936ab7f0964f56bc3312ad9ad956e978ac39895 /mm
parent021740dc30d184e3b0fa7679936e65a56090c425 (diff)
[PATCH] freepgt: free_pgtables from FIRST_USER_ADDRESS
The patches to free_pgtables by vma left problems on any architectures which leave some user address page table entries unencapsulated by vma. Andi has fixed the 32-bit vDSO on x86_64 to use a vma. Now fix arm (and arm26), whose first PAGE_SIZE is reserved (perhaps) for machine vectors. Our calls to free_pgtables must not touch that area, and exit_mmap's BUG_ON(nr_ptes) must allow that arm's get_pgd_slow may (or may not) have allocated an extra page table, which its free_pgd_slow would free later. FIRST_USER_PGD_NR has misled me and others: until all the arches define FIRST_USER_ADDRESS instead, a hack in mmap.c to derive one from t'other. This patch fixes the bugs, the remaining patches just clean it up. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mmap.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 0fa87a5ae2cc..ac6e694c3b61 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1612,6 +1612,11 @@ static void unmap_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
validate_mm(mm);
}
+#ifndef FIRST_USER_ADDRESS /* temporary hack */
+#define THIS_IS_ARM FIRST_USER_PGD_NR
+#define FIRST_USER_ADDRESS (THIS_IS_ARM * PAGE_SIZE)
+#endif
+
/*
* Get rid of page table information in the indicated region.
*
@@ -1630,7 +1635,7 @@ static void unmap_region(struct mm_struct *mm,
tlb = tlb_gather_mmu(mm, 0);
unmap_vmas(&tlb, mm, vma, start, end, &nr_accounted, NULL);
vm_unacct_memory(nr_accounted);
- free_pgtables(&tlb, vma, prev? prev->vm_end: 0,
+ free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
next? next->vm_start: 0);
tlb_finish_mmu(tlb, start, end);
spin_unlock(&mm->page_table_lock);
@@ -1910,7 +1915,7 @@ void exit_mmap(struct mm_struct *mm)
/* Use -1 here to ensure all VMAs in the mm are unmapped */
end = unmap_vmas(&tlb, mm, vma, 0, -1, &nr_accounted, NULL);
vm_unacct_memory(nr_accounted);
- free_pgtables(&tlb, vma, 0, 0);
+ free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
tlb_finish_mmu(tlb, 0, end);
mm->mmap = mm->mmap_cache = NULL;
@@ -1931,7 +1936,7 @@ void exit_mmap(struct mm_struct *mm)
vma = next;
}
- BUG_ON(mm->nr_ptes); /* This is just debugging */
+ BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
}
/* Insert vm structure into process list sorted by address

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