Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/i386/mm/pageattr.c | 28 ++++++++++++++++++----------
25-akpm/arch/x86_64/mm/pageattr.c | 26 +++++++++++++++++---------
2 files changed, 35 insertions(+), 19 deletions(-)
diff -puN arch/i386/mm/pageattr.c~pageattr-fix arch/i386/mm/pageattr.c
--- 25/arch/i386/mm/pageattr.c~pageattr-fix 2004-12-03 20:03:35.776754776 -0800
+++ 25-akpm/arch/i386/mm/pageattr.c 2004-12-03 20:03:35.782753864 -0800
@@ -117,27 +117,35 @@ __change_page_attr(struct page *page, pg
kpte_page = virt_to_page(kpte);
if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) {
if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
- pte_t old = *kpte;
- pte_t standard = mk_pte(page, PAGE_KERNEL);
set_pte_atomic(kpte, mk_pte(page, prot));
- if (pte_same(old,standard))
- get_page(kpte_page);
} else {
struct page *split = split_large_page(address, prot);
if (!split)
return -ENOMEM;
- get_page(kpte_page);
set_pmd_pte(kpte,address,mk_pte(split, PAGE_KERNEL));
+ kpte_page = split;
}
+ get_page(kpte_page);
} else if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
__put_page(kpte_page);
- }
+ } else
+ BUG();
- if (cpu_has_pse && (page_count(kpte_page) == 1)) {
- list_add(&kpte_page->lru, &df_list);
- revert_page(kpte_page, address);
- }
+ /*
+ * If the pte was reserved, it means it was created at boot
+ * time (not via split_large_page) and in turn we must not
+ * replace it with a largepage.
+ */
+ if (!PageReserved(kpte_page)) {
+ /* memleak and potential failed 2M page regeneration */
+ BUG_ON(!page_count(kpte_page));
+
+ if (cpu_has_pse && (page_count(kpte_page) == 1)) {
+ list_add(&kpte_page->lru, &df_list);
+ revert_page(kpte_page, address);
+ }
+ }
return 0;
}
diff -puN arch/x86_64/mm/pageattr.c~pageattr-fix arch/x86_64/mm/pageattr.c
--- 25/arch/x86_64/mm/pageattr.c~pageattr-fix 2004-12-03 20:03:35.778754472 -0800
+++ 25-akpm/arch/x86_64/mm/pageattr.c 2004-12-03 20:06:09.651362280 -0800
@@ -124,28 +124,36 @@ __change_page_attr(unsigned long address
kpte_flags = pte_val(*kpte);
if (pgprot_val(prot) != pgprot_val(ref_prot)) {
if ((kpte_flags & _PAGE_PSE) == 0) {
- pte_t old = *kpte;
- pte_t standard = mk_pte(page, ref_prot);
-
set_pte(kpte, mk_pte(page, prot));
- if (pte_same(old,standard))
- get_page(kpte_page);
} else {
+ /*
+ * split_large_page will take the reference for this change_page_attr
+ * on the split page.
+ */
struct page *split = split_large_page(address, prot, ref_prot);
if (!split)
return -ENOMEM;
- get_page(kpte_page);
set_pte(kpte,mk_pte(split, ref_prot));
+ kpte_page = split;
}
+ get_page(kpte_page);
} else if ((kpte_flags & _PAGE_PSE) == 0) {
set_pte(kpte, mk_pte(page, ref_prot));
__put_page(kpte_page);
- }
+ } else
+ BUG();
+
+ /* on x86-64 the direct mapping set at boot is not using 4k pages */
+ BUG_ON(PageReserved(kpte_page));
- if (page_count(kpte_page) == 1) {
+ switch (page_count(kpte_page)) {
+ case 1:
save_page(address, kpte_page);
revert_page(address, ref_prot);
- }
+ break;
+ case 0:
+ BUG(); /* memleak and failed 2M page regeneration */
+ }
return 0;
}
_