From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: 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@xxxxxxxxxx Link: https://lkml.kernel.org/r/d04ae90cc36be3fe246ea8025e5085495681c3d7.1615296150.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Acked-by: Marco Elver <elver@xxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Peter Collingbourne <pcc@xxxxxxxxxx> Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx> Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx> Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arm64/include/asm/memory.h | 4 +- arch/arm64/include/asm/mte-kasan.h | 39 +++++++++++++++++---------- mm/kasan/kasan.h | 9 +++--- 3 files changed, 32 insertions(+), 20 deletions(-) --- a/arch/arm64/include/asm/memory.h~arm64-kasan-allow-to-init-memory-when-setting-tags +++ a/arch/arm64/include/asm/memory.h @@ -250,8 +250,8 @@ static inline const void *__tag_set(cons #define arch_init_tags(max_tag) mte_init_tags(max_tag) #define arch_get_random_tag() mte_get_random_tag() #define arch_get_mem_tag(addr) mte_get_mem_tag(addr) -#define arch_set_mem_tag_range(addr, size, tag) \ - mte_set_mem_tag_range((addr), (size), (tag)) +#define arch_set_mem_tag_range(addr, size, tag, init) \ + mte_set_mem_tag_range((addr), (size), (tag), (init)) #endif /* CONFIG_KASAN_HW_TAGS */ /* --- a/arch/arm64/include/asm/mte-kasan.h~arm64-kasan-allow-to-init-memory-when-setting-tags +++ a/arch/arm64/include/asm/mte-kasan.h @@ -53,7 +53,8 @@ static inline u8 mte_get_random_tag(void * Note: The address must be non-NULL and MTE_GRANULE_SIZE aligned and * size must be non-zero and MTE_GRANULE_SIZE aligned. */ -static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag) +static inline void mte_set_mem_tag_range(void *addr, size_t size, + u8 tag, bool init) { u64 curr, end; @@ -63,18 +64,27 @@ static inline void mte_set_mem_tag_range curr = (u64)__tag_set(addr, tag); end = curr + size; - do { - /* - * 'asm volatile' is required to prevent the compiler to move - * the statement outside of the loop. - */ - asm volatile(__MTE_PREAMBLE "stg %0, [%0]" - : - : "r" (curr) - : "memory"); - - curr += MTE_GRANULE_SIZE; - } while (curr != end); + /* + * 'asm volatile' is required to prevent the compiler to move + * the statement outside of the loop. + */ + if (init) { + do { + asm volatile(__MTE_PREAMBLE "stzg %0, [%0]" + : + : "r" (curr) + : "memory"); + curr += MTE_GRANULE_SIZE; + } while (curr != end); + } else { + do { + asm volatile(__MTE_PREAMBLE "stg %0, [%0]" + : + : "r" (curr) + : "memory"); + curr += MTE_GRANULE_SIZE; + } while (curr != end); + } } void mte_enable_kernel_sync(void); @@ -101,7 +111,8 @@ static inline u8 mte_get_random_tag(void return 0xFF; } -static inline void mte_set_mem_tag_range(void *addr, size_t size, u8 tag) +static inline void mte_set_mem_tag_range(void *addr, size_t size, + u8 tag, bool init) { } --- a/mm/kasan/kasan.h~arm64-kasan-allow-to-init-memory-when-setting-tags +++ a/mm/kasan/kasan.h @@ -314,7 +314,7 @@ static inline const void *arch_kasan_set #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 #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 vo 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 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) _
