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Date:   Tue, 10 Nov 2020 23:20:14 +0100
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Subject: [PATCH v2 10/20] kasan: inline and rename kasan_unpoison_memory
From:   Andrey Konovalov <andreyknvl@google.com>
To:     Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Currently kasan_unpoison_memory() is used as both an external annotation
and as an internal memory poisoning helper. Rename external annotation to
kasan_unpoison_data() and inline the internal helper 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@google.com>
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 53c8e8b12fbc..f1a5042ae4fc 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -74,14 +74,15 @@ 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);
@@ -106,11 +107,6 @@ 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);
@@ -118,8 +114,6 @@ 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) {}
 
@@ -127,6 +121,9 @@ 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) {}
@@ -166,7 +163,6 @@ 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 1c905e4290ab..883898487b3f 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -226,7 +226,7 @@ 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 a266b90636a1..4598c1364f19 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 kasan_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 0303e49904b4..838b29e44e32 100644
--- a/mm/kasan/hw_tags.c
+++ b/mm/kasan/hw_tags.c
@@ -30,12 +30,6 @@ void kasan_init_hw_tags(void)
 	pr_info("KernelAddressSanitizer initialized\n");
 }
 
-void kasan_unpoison_memory(const void *address, size_t size)
-{
-	hw_set_mem_tag_range(kasan_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 ab7314418604..2d3c99125996 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -283,6 +283,12 @@ 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)
+{
+	hw_set_mem_tag_range(kasan_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);
@@ -295,6 +301,7 @@ 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);
-- 
2.29.2.222.g5d2a92d10f8-goog