1 files changed, 41 insertions, 2 deletions
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index fb883740fd27..222858e2e6af 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -367,12 +367,51 @@ static inline bool kasan_byte_accessible(const void *addr)
 
 #else /* CONFIG_KASAN_HW_TAGS */
 
-void kasan_poison(const void *address, size_t size, u8 value);
-void kasan_unpoison(const void *address, size_t size);
+/**
+ * kasan_poison - mark the memory range as unaccessible
+ * @addr - range start address, must be aligned to KASAN_GRANULE_SIZE
+ * @size - range size
+ * @value - value that's written to metadata for the range
+ *
+ * The size gets aligned to KASAN_GRANULE_SIZE before marking the range.
+ */
+void kasan_poison(const void *addr, size_t size, u8 value);
+
+/**
+ * kasan_unpoison - mark the memory range as accessible
+ * @addr - range start address, must be aligned to KASAN_GRANULE_SIZE
+ * @size - range size
+ *
+ * For the tag-based modes, the @size gets aligned to KASAN_GRANULE_SIZE before
+ * marking the range.
+ * For the generic mode, the last granule of the memory range gets partially
+ * unpoisoned based on the @size.
+ */
+void kasan_unpoison(const void *addr, size_t size);
+
 bool kasan_byte_accessible(const void *addr);
 
 #endif /* CONFIG_KASAN_HW_TAGS */
 
+#ifdef CONFIG_KASAN_GENERIC
+
+/**
+ * kasan_poison_last_granule - mark the last granule of the memory range as
+ * unaccessible
+ * @addr - range start address, must be aligned to KASAN_GRANULE_SIZE
+ * @size - range size
+ *
+ * This function is only available for the generic mode, as it's the only mode
+ * that has partially poisoned memory granules.
+ */
+void kasan_poison_last_granule(const void *address, size_t size);
+
+#else /* CONFIG_KASAN_GENERIC */
+
+static inline void kasan_poison_last_granule(const void *address, size_t size) { }
+
+#endif /* CONFIG_KASAN_GENERIC */
+
 /*
  * Exported functions for interfaces called from assembly or from generated
  * code. Declarations here to avoid warning about missing declarations.