mm/kasan: introduce __kasan_check_{read,write}

Patch series "mm/kasan: Add object validation in ksize()", v3.

This patch (of 5):

This introduces __kasan_check_{read,write}.  __kasan_check functions may
be used from anywhere, even compilation units that disable instrumentation
selectively.

This change eliminates the need for the __KASAN_INTERNAL definition.

[[email protected]: v5]
  Link: http://lkml.kernel.org/r/[email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Marco Elver <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Reviewed-by: Andrey Ryabinin <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Kees Cook <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 22 insertions, 3 deletions

diff --git a/include/linux/kasan-checks.h b/include/linux/kasan-checks.h
index a61dc075e2ce..221f05fbddd7 100644
--- a/include/linux/kasan-checks.h
+++ b/include/linux/kasan-checks.h
@@ -2,9 +2,28 @@
 #ifndef _LINUX_KASAN_CHECKS_H
 #define _LINUX_KASAN_CHECKS_H
 
-#if defined(__SANITIZE_ADDRESS__) || defined(__KASAN_INTERNAL)
-void kasan_check_read(const volatile void *p, unsigned int size);
-void kasan_check_write(const volatile void *p, unsigned int size);
+/*
+ * __kasan_check_*: Always available when KASAN is enabled. This may be used
+ * even in compilation units that selectively disable KASAN, but must use KASAN
+ * to validate access to an address.   Never use these in header files!
+ */
+#ifdef CONFIG_KASAN
+void __kasan_check_read(const volatile void *p, unsigned int size);
+void __kasan_check_write(const volatile void *p, unsigned int size);
+#else
+static inline void __kasan_check_read(const volatile void *p, unsigned int size)
+{ }
+static inline void __kasan_check_write(const volatile void *p, unsigned int size)
+{ }
+#endif
+
+/*
+ * kasan_check_*: Only available when the particular compilation unit has KASAN
+ * instrumentation enabled. May be used in header files.
+ */
+#ifdef __SANITIZE_ADDRESS__
+#define kasan_check_read __kasan_check_read
+#define kasan_check_write __kasan_check_write
 #else
 static inline void kasan_check_read(const volatile void *p, unsigned int size)
 { }