This adds support for highmem pages poisoning and verification to the
debug-pagealloc feature for no-architecture support.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
---
* v2
- unify the handling of highmem and no-highmem pages
mm/debug-pagealloc.c | 47 ++++++++++++++---------------------------------
1 files changed, 14 insertions(+), 33 deletions(-)
diff --git a/mm/debug-pagealloc.c b/mm/debug-pagealloc.c
index 2618933..bda7ed0 100644
--- a/mm/debug-pagealloc.c
+++ b/mm/debug-pagealloc.c
@@ -1,6 +1,7 @@
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
+#include <linux/highmem.h>
#include <linux/page-debug-flags.h>
#include <linux/poison.h>
#include <linux/ratelimit.h>
@@ -20,28 +21,16 @@ static inline bool page_poison(struct page *page)
return test_bit(PAGE_DEBUG_FLAG_POISON, &page->debug_flags);
}
-static void poison_highpage(struct page *page)
-{
- /*
- * Page poisoning for highmem pages is not implemented.
- *
- * This can be called from interrupt contexts.
- * So we need to create a new kmap_atomic slot for this
- * application and it will need interrupt protection.
- */
-}
-
static void poison_page(struct page *page)
{
void *addr;
- if (PageHighMem(page)) {
- poison_highpage(page);
- return;
- }
+ preempt_disable();
+ addr = kmap_atomic(page);
set_page_poison(page);
- addr = page_address(page);
memset(addr, PAGE_POISON, PAGE_SIZE);
+ kunmap_atomic(addr);
+ preempt_enable();
}
static void poison_pages(struct page *page, int n)
@@ -86,27 +75,19 @@ static void check_poison_mem(unsigned char *mem, size_t bytes)
dump_stack();
}
-static void unpoison_highpage(struct page *page)
-{
- /*
- * See comment in poison_highpage().
- * Highmem pages should not be poisoned for now
- */
- BUG_ON(page_poison(page));
-}
-
static void unpoison_page(struct page *page)
{
- if (PageHighMem(page)) {
- unpoison_highpage(page);
+ void *addr;
+
+ if (!page_poison(page))
return;
- }
- if (page_poison(page)) {
- void *addr = page_address(page);
- check_poison_mem(addr, PAGE_SIZE);
- clear_page_poison(page);
- }
+ preempt_disable();
+ addr = kmap_atomic(page);
+ check_poison_mem(addr, PAGE_SIZE);
+ clear_page_poison(page);
+ kunmap_atomic(addr);
+ preempt_enable();
}
static void unpoison_pages(struct page *page, int n)
--
1.7.4.4
--
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