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-rw-r--r--arch/x86/mm/pageattr.c19
-rw-r--r--include/linux/mm.h6
-rw-r--r--kernel/power/snapshot.c42
3 files changed, 53 insertions, 14 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index e2a74ea..464d8fc 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -899,7 +899,24 @@ void kernel_map_pages(struct page *page, int numpages, int enable)
*/
cpa_fill_pool();
}
-#endif
+
+#ifdef CONFIG_HIBERNATION
+
+bool kernel_page_present(struct page *page)
+{
+ unsigned int level;
+ pte_t *pte;
+
+ if (PageHighMem(page))
+ return false;
+
+ pte = lookup_address((unsigned long)page_address(page), &level);
+ return (pte_val(*pte) & _PAGE_PRESENT);
+}
+
+#endif /* CONFIG_HIBERNATION */
+
+#endif /* CONFIG_DEBUG_PAGEALLOC */
/*
* The testcases use internal knowledge of the implementation that shouldn't
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 26c7124..3b3e134 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1171,12 +1171,18 @@ static inline void enable_debug_pagealloc(void)
{
debug_pagealloc_enabled = 1;
}
+#ifdef CONFIG_HIBERNATION
+extern bool kernel_page_present(struct page *page);
+#endif /* CONFIG_HIBERNATION */
#else
static inline void
kernel_map_pages(struct page *page, int numpages, int enable) {}
static inline void enable_debug_pagealloc(void)
{
}
+#ifdef CONFIG_HIBERNATION
+static inline bool kernel_page_present(struct page *page) { return true; }
+#endif /* CONFIG_HIBERNATION */
#endif
extern struct vm_area_struct *get_gate_vma(struct task_struct *tsk);
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 95250d7..72a020c 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -875,8 +875,8 @@ static inline void *saveable_highmem_page(unsigned long pfn) { return NULL; }
#endif /* CONFIG_HIGHMEM */
/**
- * saveable - Determine whether a non-highmem page should be included in
- * the suspend image.
+ * saveable_page - Determine whether a non-highmem page should be included
+ * in the suspend image.
*
* We should save the page if it isn't Nosave, and is not in the range
* of pages statically defined as 'unsaveable', and it isn't a part of
@@ -897,7 +897,8 @@ static struct page *saveable_page(unsigned long pfn)
if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
return NULL;
- if (PageReserved(page) && pfn_is_nosave(pfn))
+ if (PageReserved(page)
+ && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
return NULL;
return page;
@@ -938,6 +939,25 @@ static inline void do_copy_page(long *dst, long *src)
*dst++ = *src++;
}
+
+/**
+ * safe_copy_page - check if the page we are going to copy is marked as
+ * present in the kernel page tables (this always is the case if
+ * CONFIG_DEBUG_PAGEALLOC is not set and in that case
+ * kernel_page_present() always returns 'true').
+ */
+static void safe_copy_page(void *dst, struct page *s_page)
+{
+ if (kernel_page_present(s_page)) {
+ do_copy_page(dst, page_address(s_page));
+ } else {
+ kernel_map_pages(s_page, 1, 1);
+ do_copy_page(dst, page_address(s_page));
+ kernel_map_pages(s_page, 1, 0);
+ }
+}
+
+
#ifdef CONFIG_HIGHMEM
static inline struct page *
page_is_saveable(struct zone *zone, unsigned long pfn)
@@ -946,8 +966,7 @@ page_is_saveable(struct zone *zone, unsigned long pfn)
saveable_highmem_page(pfn) : saveable_page(pfn);
}
-static inline void
-copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
+static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
{
struct page *s_page, *d_page;
void *src, *dst;
@@ -961,29 +980,26 @@ copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
kunmap_atomic(src, KM_USER0);
kunmap_atomic(dst, KM_USER1);
} else {
- src = page_address(s_page);
if (PageHighMem(d_page)) {
/* Page pointed to by src may contain some kernel
* data modified by kmap_atomic()
*/
- do_copy_page(buffer, src);
+ safe_copy_page(buffer, s_page);
dst = kmap_atomic(pfn_to_page(dst_pfn), KM_USER0);
memcpy(dst, buffer, PAGE_SIZE);
kunmap_atomic(dst, KM_USER0);
} else {
- dst = page_address(d_page);
- do_copy_page(dst, src);
+ safe_copy_page(page_address(d_page), s_page);
}
}
}
#else
#define page_is_saveable(zone, pfn) saveable_page(pfn)
-static inline void
-copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
+static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
{
- do_copy_page(page_address(pfn_to_page(dst_pfn)),
- page_address(pfn_to_page(src_pfn)));
+ safe_copy_page(page_address(pfn_to_page(dst_pfn)),
+ pfn_to_page(src_pfn));
}
#endif /* CONFIG_HIGHMEM */
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