[PATCH RFC v2 12/21] kasan: inline and rename kasan_unpoison_memory

[Andrey Konovalov]

Currently kasan_unpoison_memory() is used as both an external annotation
and as internal memory poisoning helper. Rename external annotation to
kasan_unpoison_data() and inline the internal helper for for hardware
tag-based mode to avoid undeeded function calls.

There's the external annotation kasan_unpoison_slab() that is currently
defined as static inline and uses kasan_unpoison_memory(). With this
change it's turned into a function call. Overall, this results in the
same number of calls for hardware tag-based mode as
kasan_unpoison_memory() is now inlined.

Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Link: https://linux-review.googlesource.com/id/Ia7c8b659f79209935cbaab3913bf7f082cc43a0e
---
 include/linux/kasan.h | 16 ++++++----------
 kernel/fork.c         |  2 +-
 mm/kasan/common.c     | 10 ++++++++++
 mm/kasan/hw_tags.c    |  6 ------
 mm/kasan/kasan.h      |  7 +++++++
 mm/slab_common.c      |  2 +-
 6 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 6377d7d3a951..2b9023224474 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -66,14 +66,15 @@ static inline void kasan_disable_current(void) {}
 
 #ifdef CONFIG_KASAN
 
-void kasan_unpoison_memory(const void *address, size_t size);
-
 void kasan_alloc_pages(struct page *page, unsigned int order);
 void kasan_free_pages(struct page *page, unsigned int order);
 
 void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
 			slab_flags_t *flags);
 
+void kasan_unpoison_data(const void *address, size_t size);
+void kasan_unpoison_slab(const void *ptr);
+
 void kasan_poison_slab(struct page *page);
 void kasan_unpoison_object_data(struct kmem_cache *cache, void *object);
 void kasan_poison_object_data(struct kmem_cache *cache, void *object);
@@ -98,11 +99,6 @@ struct kasan_cache {
 	int free_meta_offset;
 };
 
-size_t __ksize(const void *);
-static inline void kasan_unpoison_slab(const void *ptr)
-{
-	kasan_unpoison_memory(ptr, __ksize(ptr));
-}
 size_t kasan_metadata_size(struct kmem_cache *cache);
 
 bool kasan_save_enable_multi_shot(void);
@@ -110,8 +106,6 @@ void kasan_restore_multi_shot(bool enabled);
 
 #else /* CONFIG_KASAN */
 
-static inline void kasan_unpoison_memory(const void *address, size_t size) {}
-
 static inline void kasan_alloc_pages(struct page *page, unsigned int order) {}
 static inline void kasan_free_pages(struct page *page, unsigned int order) {}
 
@@ -119,6 +113,9 @@ static inline void kasan_cache_create(struct kmem_cache *cache,
 				      unsigned int *size,
 				      slab_flags_t *flags) {}
 
+static inline void kasan_unpoison_data(const void *address, size_t size) { }
+static inline void kasan_unpoison_slab(const void *ptr) { }
+
 static inline void kasan_poison_slab(struct page *page) {}
 static inline void kasan_unpoison_object_data(struct kmem_cache *cache,
 					void *object) {}
@@ -158,7 +155,6 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object,
 	return false;
 }
 
-static inline void kasan_unpoison_slab(const void *ptr) { }
 static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 
 #endif /* CONFIG_KASAN */
diff --git a/kernel/fork.c b/kernel/fork.c
index b41fecca59d7..858d78eee6ec 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -225,7 +225,7 @@ static unsigned long *alloc_thread_stack_node(struct task_struct *tsk, int node)
 			continue;
 
 		/* Mark stack accessible for KASAN. */
-		kasan_unpoison_memory(s->addr, THREAD_SIZE);
+		kasan_unpoison_data(s->addr, THREAD_SIZE);
 
 		/* Clear stale pointers from reused stack. */
 		memset(s->addr, 0, THREAD_SIZE);
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 9008fc6b0810..1a5e6c279a72 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -184,6 +184,16 @@ struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
 	return (void *)reset_tag(object) + cache->kasan_info.free_meta_offset;
 }
 
+void kasan_unpoison_data(const void *address, size_t size)
+{
+	kasan_unpoison_memory(address, size);
+}
+
+void kasan_unpoison_slab(const void *ptr)
+{
+	kasan_unpoison_memory(ptr, __ksize(ptr));
+}
+
 void kasan_poison_slab(struct page *page)
 {
 	unsigned long i;
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
index f03161f3da19..915142da6b57 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -24,12 +24,6 @@ void __init kasan_init_tags(void)
 	pr_info("KernelAddressSanitizer initialized\n");
 }
 
-void kasan_unpoison_memory(const void *address, size_t size)
-{
-	set_mem_tag_range(reset_tag(address),
-			  round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
-}
-
 void kasan_set_free_info(struct kmem_cache *cache,
 				void *object, u8 tag)
 {
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 8d84ae6f58f1..da08b2533d73 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -280,6 +280,12 @@ static inline void kasan_poison_memory(const void *address, size_t size, u8 valu
 			  round_up(size, KASAN_GRANULE_SIZE), value);
 }
 
+static inline void kasan_unpoison_memory(const void *address, size_t size)
+{
+	set_mem_tag_range(reset_tag(address),
+			  round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
+}
+
 static inline bool check_invalid_free(void *addr)
 {
 	u8 ptr_tag = get_tag(addr);
@@ -292,6 +298,7 @@ static inline bool check_invalid_free(void *addr)
 #else /* CONFIG_KASAN_HW_TAGS */
 
 void kasan_poison_memory(const void *address, size_t size, u8 value);
+void kasan_unpoison_memory(const void *address, size_t size);
 bool check_invalid_free(void *addr);
 
 #endif /* CONFIG_KASAN_HW_TAGS */
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 53d0f8bb57ea..f1b0c4a22f08 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -1176,7 +1176,7 @@ size_t ksize(const void *objp)
 	 * We assume that ksize callers could use whole allocated area,
 	 * so we need to unpoison this area.
 	 */
-	kasan_unpoison_memory(objp, size);
+	kasan_unpoison_data(objp, size);
 	return size;
 }
 EXPORT_SYMBOL(ksize);
-- 
2.29.0.rc1.297.gfa9743e501-goog