kasan, mm: integrate slab init_on_alloc with HW_TAGS

This change uses the previously added memory initialization feature of
HW_TAGS KASAN routines for slab memory when init_on_alloc is enabled.

With this change, memory initialization memset() is no longer called when
both HW_TAGS KASAN and init_on_alloc are enabled.  Instead, memory is
initialized in KASAN runtime.

The memory initialization memset() is moved into slab_post_alloc_hook()
that currently directly follows the initialization loop.  A new argument
is added to slab_post_alloc_hook() that indicates whether to initialize
the memory or not.

To avoid discrepancies with which memory gets initialized that can be
caused by future changes, both KASAN hook and initialization memset() are
put together and a warning comment is added.

Combining setting allocation tags with memory initialization improves
HW_TAGS KASAN performance when init_on_alloc is enabled.

Link: https://lkml.kernel.org/r/c1292aeb5d519da221ec74a0684a949b027d7720.1615296150.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 30aa2bee8400..629aee484b6c 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -226,12 +226,12 @@ static __always_inline void kasan_slab_free_mempool(void *ptr)
 }
 
 void * __must_check __kasan_slab_alloc(struct kmem_cache *s,
-				       void *object, gfp_t flags);
+				       void *object, gfp_t flags, bool init);
 static __always_inline void * __must_check kasan_slab_alloc(
-				struct kmem_cache *s, void *object, gfp_t flags)
+		struct kmem_cache *s, void *object, gfp_t flags, bool init)
 {
 	if (kasan_enabled())
-		return __kasan_slab_alloc(s, object, flags);
+		return __kasan_slab_alloc(s, object, flags, init);
 	return object;
 }
 
@@ -320,7 +320,7 @@ static inline bool kasan_slab_free(struct kmem_cache *s, void *object)
 static inline void kasan_kfree_large(void *ptr) {}
 static inline void kasan_slab_free_mempool(void *ptr) {}
 static inline void *kasan_slab_alloc(struct kmem_cache *s, void *object,
-				   gfp_t flags)
+				   gfp_t flags, bool init)
 {
 	return object;
 }