[PATCH v7 14/41] kasan: shadow declarations only for software modes

[Andrey Konovalov <andreyknvl@google.com>]

This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.

Group shadow-related KASAN function declarations and only define them
for the two existing software modes.

No functional changes for software modes.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
---
Change-Id: I864be75a88b91b443c55e9c2042865e15703e164
---
 include/linux/kasan.h | 45 ++++++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 16 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 59538e795df4..45345dd5cfd6 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -10,9 +10,20 @@ struct vm_struct;
 struct task_struct;
 
 #ifdef CONFIG_KASAN
+#include <asm/kasan.h>
+#endif
+
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 
 #include <linux/pgtable.h>
-#include <asm/kasan.h>
+
+/* Software KASAN implementations use shadow memory. */
+
+#ifdef CONFIG_KASAN_SW_TAGS
+#define KASAN_SHADOW_INIT 0xFF
+#else
+#define KASAN_SHADOW_INIT 0
+#endif
 
 /* kasan_data struct is used in KUnit tests for KASAN expected failures */
 struct kunit_kasan_expectation {
@@ -35,6 +46,23 @@ static inline void *kasan_mem_to_shadow(const void *addr)
 		+ KASAN_SHADOW_OFFSET;
 }
 
+int kasan_add_zero_shadow(void *start, unsigned long size);
+void kasan_remove_zero_shadow(void *start, unsigned long size);
+
+#else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
+static inline int kasan_add_zero_shadow(void *start, unsigned long size)
+{
+	return 0;
+}
+static inline void kasan_remove_zero_shadow(void *start,
+					unsigned long size)
+{}
+
+#endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */
+
+#ifdef CONFIG_KASAN
+
 /* Enable reporting bugs after kasan_disable_current() */
 extern void kasan_enable_current(void);
 
@@ -75,9 +103,6 @@ struct kasan_cache {
 	int free_meta_offset;
 };
 
-int kasan_add_zero_shadow(void *start, unsigned long size);
-void kasan_remove_zero_shadow(void *start, unsigned long size);
-
 size_t __ksize(const void *);
 static inline void kasan_unpoison_slab(const void *ptr)
 {
@@ -143,14 +168,6 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
 	return false;
 }
 
-static inline int kasan_add_zero_shadow(void *start, unsigned long size)
-{
-	return 0;
-}
-static inline void kasan_remove_zero_shadow(void *start,
-					unsigned long size)
-{}
-
 static inline void kasan_unpoison_slab(const void *ptr) { }
 static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 
@@ -158,8 +175,6 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 
 #ifdef CONFIG_KASAN_GENERIC
 
-#define KASAN_SHADOW_INIT 0
-
 void kasan_cache_shrink(struct kmem_cache *cache);
 void kasan_cache_shutdown(struct kmem_cache *cache);
 void kasan_record_aux_stack(void *ptr);
@@ -174,8 +189,6 @@ static inline void kasan_record_aux_stack(void *ptr) {}
 
 #ifdef CONFIG_KASAN_SW_TAGS
 
-#define KASAN_SHADOW_INIT 0xFF
-
 void kasan_init_tags(void);
 
 void *kasan_reset_tag(const void *addr);
-- 
2.29.1.341.ge80a0c044ae-goog