When a kernel is loaded for kexec the address ranges where the kexec
segments will be copied to may conflict with pages already set to be
preserved. Provide a way to determine if preserved pages exist in a
specified range.
Signed-off-by: Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>
---
include/linux/pkram.h | 2 ++
mm/pkram.c | 20 ++++++++++++++++++++
2 files changed, 22 insertions(+)
diff --git a/include/linux/pkram.h b/include/linux/pkram.h
index 97a7c2ac44a9..977cf45a1bcf 100644
--- a/include/linux/pkram.h
+++ b/include/linux/pkram.h
@@ -104,11 +104,13 @@ int pkram_prepare_save(struct pkram_stream *ps, const char *name,
void pkram_reserve(void);
void pkram_cleanup(void);
void pkram_ban_region(unsigned long start, unsigned long end);
+int pkram_has_preserved_pages(unsigned long start, unsigned long end);
#else
#define pkram_reserved_pages 0UL
static inline void pkram_reserve(void) { }
static inline void pkram_cleanup(void) { }
static inline void pkram_ban_region(unsigned long start, unsigned long end) { }
+static inline int pkram_has_preserved_pages(unsigned long start, unsigned long end) { return 0; }
#endif
#endif /* _LINUX_PKRAM_H */
diff --git a/mm/pkram.c b/mm/pkram.c
index d15be75c1032..dcf84ba785a7 100644
--- a/mm/pkram.c
+++ b/mm/pkram.c
@@ -1668,3 +1668,23 @@ void __init pkram_cleanup(void)
pkram_reserved_pages--;
}
}
+
+static int has_preserved_pages_cb(unsigned long base, unsigned long size, void *private)
+{
+ int *has_preserved = (int *)private;
+
+ *has_preserved = 1;
+ return 1;
+}
+
+/*
+ * Check whether the memory range [start, end) contains preserved pages.
+ */
+int pkram_has_preserved_pages(unsigned long start, unsigned long end)
+{
+ int has_preserved = 0;
+
+ pkram_find_preserved(start, end, &has_preserved, has_preserved_pages_cb);
+
+ return has_preserved;
+}
--
1.8.3.1
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