tree b936ab7f0964f56bc3312ad9ad956e978ac39895
parent 021740dc30d184e3b0fa7679936e65a56090c425
author Hugh Dickins <[EMAIL PROTECTED]> Wed, 20 Apr 2005 03:29:19 -0700
committer Linus Torvalds <[EMAIL PROTECTED](none)> Wed, 20 Apr 2005 03:29:19
-0700
[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 <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
mmap.c | 11 ++++++++---
1 files changed, 8 insertions(+), 3 deletions(-)
Index: mm/mmap.c
===================================================================
--- c31bd23fe74038b4bab5148e17e07745b75b453d/mm/mmap.c (mode:100644
sha1:0fa87a5ae2ccd80bde1403171022c4643dbb41f5)
+++ b936ab7f0964f56bc3312ad9ad956e978ac39895/mm/mmap.c (mode:100644
sha1:ac6e694c3b61054174be206382b8a796698c89ed)
@@ -1612,6 +1612,11 @@
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 @@
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 @@
/* 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 @@
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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