arm64: kasan: allow to init memory when setting tags

Patch series "kasan: integrate with init_on_alloc/free", v3.

This patch series integrates HW_TAGS KASAN with init_on_alloc/free by
initializing memory via the same arm64 instruction that sets memory tags.

This is expected to improve HW_TAGS KASAN performance when
init_on_alloc/free is enabled.  The exact perfomance numbers are unknown
as MTE-enabled hardware doesn't exist yet.

This patch (of 5):

This change adds an argument to mte_set_mem_tag_range() that allows to
enable memory initialization when settinh the allocation tags.  The
implementation uses stzg instruction instead of stg when this argument
indicates to initialize memory.

Combining setting allocation tags with memory initialization will improve
HW_TAGS KASAN performance when init_on_alloc/free is enabled.

This change doesn't integrate memory initialization with KASAN, this is
done is subsequent patches in this series.

Link: https://lkml.kernel.org/r/cover.1615296150.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/d04ae90cc36be3fe246ea8025e5085495681c3d7.1615296150.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 4 deletions

diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 552f8381d988..0583033a7df6 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -314,7 +314,7 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 #define arch_get_mem_tag(addr)	(0xFF)
 #endif
 #ifndef arch_set_mem_tag_range
-#define arch_set_mem_tag_range(addr, size, tag) ((void *)(addr))
+#define arch_set_mem_tag_range(addr, size, tag, init) ((void *)(addr))
 #endif
 
 #define hw_enable_tagging_sync()		arch_enable_tagging_sync()
@@ -324,7 +324,8 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
 #define hw_force_async_tag_fault()		arch_force_async_tag_fault()
 #define hw_get_random_tag()			arch_get_random_tag()
 #define hw_get_mem_tag(addr)			arch_get_mem_tag(addr)
-#define hw_set_mem_tag_range(addr, size, tag)	arch_set_mem_tag_range((addr), (size), (tag))
+#define hw_set_mem_tag_range(addr, size, tag, init) \
+			arch_set_mem_tag_range((addr), (size), (tag), (init))
 
 #else /* CONFIG_KASAN_HW_TAGS */
 
@@ -371,7 +372,7 @@ static inline void kasan_poison(const void *addr, size_t size, u8 value)
 	if (WARN_ON(size & KASAN_GRANULE_MASK))
 		return;
 
-	hw_set_mem_tag_range((void *)addr, size, value);
+	hw_set_mem_tag_range((void *)addr, size, value, false);
 }
 
 static inline void kasan_unpoison(const void *addr, size_t size)
@@ -388,7 +389,7 @@ static inline void kasan_unpoison(const void *addr, size_t size)
 		return;
 	size = round_up(size, KASAN_GRANULE_SIZE);
 
-	hw_set_mem_tag_range((void *)addr, size, tag);
+	hw_set_mem_tag_range((void *)addr, size, tag, false);
 }
 
 static inline bool kasan_byte_accessible(const void *addr)