diff options
author | Nick Piggin <nickpiggin@yahoo.com.au> | 2005-09-28 00:45:18 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-28 10:46:40 -0400 |
commit | 8b1f3124618b54cf125dea3a074b9cf469117723 (patch) | |
tree | 19ef8a7fe9cc5b1c46dc973ea151edab4aba2b8a /include | |
parent | 95001ee9256df846e374f116c92ca8e0beec1527 (diff) |
[PATCH] mm: move_pte to remap ZERO_PAGE
Move the ZERO_PAGE remapping complexity to the move_pte macro in
asm-generic, have it conditionally depend on
__HAVE_ARCH_MULTIPLE_ZERO_PAGE, which gets defined for MIPS.
For architectures without __HAVE_ARCH_MULTIPLE_ZERO_PAGE, move_pte becomes
a noop.
From: Hugh Dickins <hugh@veritas.com>
Fix nasty little bug we've missed in Nick's mremap move ZERO_PAGE patch.
The "pte" at that point may be a swap entry or a pte_file entry: we must
check pte_present before perhaps corrupting such an entry.
Patch below against 2.6.14-rc2-mm1, but the same bug is in 2.6.14-rc2's
mm/mremap.c, and more dangerous there since it's affecting all arches: I
think the safest course is to send Nick's patch and Yoichi's build fix and
this fix (build tested) on to Linus - so only MIPS can be affected.
Signed-off-by: Nick Piggin <npiggin@suse.de>
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 'include')
-rw-r--r-- | include/asm-generic/pgtable.h | 13 | ||||
-rw-r--r-- | include/asm-mips/pgtable.h | 2 |
2 files changed, 15 insertions, 0 deletions
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index f86c1e549466..ff28c8b31f58 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h | |||
@@ -158,6 +158,19 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres | |||
158 | #define lazy_mmu_prot_update(pte) do { } while (0) | 158 | #define lazy_mmu_prot_update(pte) do { } while (0) |
159 | #endif | 159 | #endif |
160 | 160 | ||
161 | #ifndef __HAVE_ARCH_MULTIPLE_ZERO_PAGE | ||
162 | #define move_pte(pte, prot, old_addr, new_addr) (pte) | ||
163 | #else | ||
164 | #define move_pte(pte, prot, old_addr, new_addr) \ | ||
165 | ({ \ | ||
166 | pte_t newpte = (pte); \ | ||
167 | if (pte_present(pte) && pfn_valid(pte_pfn(pte)) && \ | ||
168 | pte_page(pte) == ZERO_PAGE(old_addr)) \ | ||
169 | newpte = mk_pte(ZERO_PAGE(new_addr), (prot)); \ | ||
170 | newpte; \ | ||
171 | }) | ||
172 | #endif | ||
173 | |||
161 | /* | 174 | /* |
162 | * When walking page tables, get the address of the next boundary, | 175 | * When walking page tables, get the address of the next boundary, |
163 | * or the end address of the range if that comes earlier. Although no | 176 | * or the end address of the range if that comes earlier. Although no |
diff --git a/include/asm-mips/pgtable.h b/include/asm-mips/pgtable.h index cbd1672c94cb..eaf5d9b3a0e1 100644 --- a/include/asm-mips/pgtable.h +++ b/include/asm-mips/pgtable.h | |||
@@ -68,6 +68,8 @@ extern unsigned long zero_page_mask; | |||
68 | #define ZERO_PAGE(vaddr) \ | 68 | #define ZERO_PAGE(vaddr) \ |
69 | (virt_to_page(empty_zero_page + (((unsigned long)(vaddr)) & zero_page_mask))) | 69 | (virt_to_page(empty_zero_page + (((unsigned long)(vaddr)) & zero_page_mask))) |
70 | 70 | ||
71 | #define __HAVE_ARCH_MULTIPLE_ZERO_PAGE | ||
72 | |||
71 | extern void paging_init(void); | 73 | extern void paging_init(void); |
72 | 74 | ||
73 | /* | 75 | /* |