On Thu, Oct 22, 2020 at 3:20 PM Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > > Declare the kasan_enabled static key in include/linux/kasan.h and in > include/linux/mm.h and check it in all kasan annotations. This allows to > avoid any slowdown caused by function calls when kasan_enabled is > disabled. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > Link: https://linux-review.googlesource.com/id/I2589451d3c96c97abbcbf714baabe6161c6f153e > --- > include/linux/kasan.h | 210 ++++++++++++++++++++++++++++++++---------- > include/linux/mm.h | 27 ++++-- > mm/kasan/common.c | 60 ++++++------ > 3 files changed, 211 insertions(+), 86 deletions(-) > > diff --git a/include/linux/kasan.h b/include/linux/kasan.h > index 2b9023224474..8654275aa62e 100644 > --- a/include/linux/kasan.h > +++ b/include/linux/kasan.h > @@ -2,6 +2,7 @@ > #ifndef _LINUX_KASAN_H > #define _LINUX_KASAN_H > > +#include <linux/jump_label.h> > #include <linux/types.h> > > struct kmem_cache; > @@ -66,40 +67,154 @@ static inline void kasan_disable_current(void) {} > > #ifdef CONFIG_KASAN > > -void kasan_alloc_pages(struct page *page, unsigned int order); > -void kasan_free_pages(struct page *page, unsigned int order); > +struct kasan_cache { > + int alloc_meta_offset; > + int free_meta_offset; > +}; > + > +#ifdef CONFIG_KASAN_HW_TAGS > +DECLARE_STATIC_KEY_FALSE(kasan_enabled); > +#else > +DECLARE_STATIC_KEY_TRUE(kasan_enabled); > +#endif > > -void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > - slab_flags_t *flags); > +void __kasan_alloc_pages(struct page *page, unsigned int order); > +static inline void kasan_alloc_pages(struct page *page, unsigned int order) > +{ > + if (static_branch_likely(&kasan_enabled)) > + __kasan_alloc_pages(page, order); The patch looks fine per se, but I think with the suggestion in the previous patch, this should be: if (kasan_is_enabled()) __kasan_alloc_pages(page, order); No overhead for other modes and less logic duplication. > +} > > -void kasan_unpoison_data(const void *address, size_t size); > -void kasan_unpoison_slab(const void *ptr); > +void __kasan_free_pages(struct page *page, unsigned int order); > +static inline void kasan_free_pages(struct page *page, unsigned int order) > +{ > + if (static_branch_likely(&kasan_enabled)) > + __kasan_free_pages(page, order); > +} > > -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); > -void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, > - const void *object); > +void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > + slab_flags_t *flags); > +static inline void kasan_cache_create(struct kmem_cache *cache, > + unsigned int *size, slab_flags_t *flags) > +{ > + if (static_branch_likely(&kasan_enabled)) > + __kasan_cache_create(cache, size, flags); > +} > > -void * __must_check kasan_kmalloc_large(const void *ptr, size_t size, > - gfp_t flags); > -void kasan_kfree_large(void *ptr, unsigned long ip); > -void kasan_poison_kfree(void *ptr, unsigned long ip); > -void * __must_check kasan_kmalloc(struct kmem_cache *s, const void *object, > - size_t size, gfp_t flags); > -void * __must_check kasan_krealloc(const void *object, size_t new_size, > - gfp_t flags); > +size_t __kasan_metadata_size(struct kmem_cache *cache); > +static inline size_t kasan_metadata_size(struct kmem_cache *cache) > +{ > + if (static_branch_likely(&kasan_enabled)) > + return __kasan_metadata_size(cache); > + return 0; > +} > > -void * __must_check kasan_slab_alloc(struct kmem_cache *s, void *object, > - gfp_t flags); > -bool kasan_slab_free(struct kmem_cache *s, void *object, unsigned long ip); > +void __kasan_unpoison_data(const void *addr, size_t size); > +static inline void kasan_unpoison_data(const void *addr, size_t size) > +{ > + if (static_branch_likely(&kasan_enabled)) > + __kasan_unpoison_data(addr, size); > +} > > -struct kasan_cache { > - int alloc_meta_offset; > - int free_meta_offset; > -}; > +void __kasan_unpoison_slab(const void *ptr); > +static inline void kasan_unpoison_slab(const void *ptr) > +{ > + if (static_branch_likely(&kasan_enabled)) > + __kasan_unpoison_slab(ptr); > +} > + > +void __kasan_poison_slab(struct page *page); > +static inline void kasan_poison_slab(struct page *page) > +{ > + if (static_branch_likely(&kasan_enabled)) > + return __kasan_poison_slab(page); > +} > + > +void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object); > +static inline void kasan_unpoison_object_data(struct kmem_cache *cache, void *object) > +{ > + if (static_branch_likely(&kasan_enabled)) > + return __kasan_unpoison_object_data(cache, object); > +} > + > +void __kasan_poison_object_data(struct kmem_cache *cache, void *object); > +static inline void kasan_poison_object_data(struct kmem_cache *cache, void *object) > +{ > + if (static_branch_likely(&kasan_enabled)) > + __kasan_poison_object_data(cache, object); > +} > + > +void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, > + const void *object); > +static inline void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, > + const void *object) > +{ > + if (static_branch_likely(&kasan_enabled)) > + return __kasan_init_slab_obj(cache, object); > + return (void *)object; > +} > + > +bool __kasan_slab_free(struct kmem_cache *s, void *object, unsigned long ip); > +static inline bool kasan_slab_free(struct kmem_cache *s, void *object, unsigned long ip) > +{ > + if (static_branch_likely(&kasan_enabled)) > + return __kasan_slab_free(s, object, ip); > + return false; > +} > > -size_t kasan_metadata_size(struct kmem_cache *cache); > +void * __must_check __kasan_slab_alloc(struct kmem_cache *s, > + void *object, gfp_t flags); > +static inline void * __must_check kasan_slab_alloc(struct kmem_cache *s, > + void *object, gfp_t flags) > +{ > + if (static_branch_likely(&kasan_enabled)) > + return __kasan_slab_alloc(s, object, flags); > + return object; > +} > + > +void * __must_check __kasan_kmalloc(struct kmem_cache *s, const void *object, > + size_t size, gfp_t flags); > +static inline void * __must_check kasan_kmalloc(struct kmem_cache *s, const void *object, > + size_t size, gfp_t flags) > +{ > + if (static_branch_likely(&kasan_enabled)) > + return __kasan_kmalloc(s, object, size, flags); > + return (void *)object; > +} > + > +void * __must_check __kasan_kmalloc_large(const void *ptr, > + size_t size, gfp_t flags); > +static inline void * __must_check kasan_kmalloc_large(const void *ptr, > + size_t size, gfp_t flags) > +{ > + if (static_branch_likely(&kasan_enabled)) > + return __kasan_kmalloc_large(ptr, size, flags); > + return (void *)ptr; > +} > + > +void * __must_check __kasan_krealloc(const void *object, > + size_t new_size, gfp_t flags); > +static inline void * __must_check kasan_krealloc(const void *object, > + size_t new_size, gfp_t flags) > +{ > + if (static_branch_likely(&kasan_enabled)) > + return __kasan_krealloc(object, new_size, flags); > + return (void *)object; > +} > + > +void __kasan_poison_kfree(void *ptr, unsigned long ip); > +static inline void kasan_poison_kfree(void *ptr, unsigned long ip) > +{ > + if (static_branch_likely(&kasan_enabled)) > + __kasan_poison_kfree(ptr, ip); > +} > + > +void __kasan_kfree_large(void *ptr, unsigned long ip); > +static inline void kasan_kfree_large(void *ptr, unsigned long ip) > +{ > + if (static_branch_likely(&kasan_enabled)) > + __kasan_kfree_large(ptr, ip); > +} > > bool kasan_save_enable_multi_shot(void); > void kasan_restore_multi_shot(bool enabled); > @@ -108,14 +223,12 @@ void kasan_restore_multi_shot(bool enabled); > > static inline void kasan_alloc_pages(struct page *page, unsigned int order) {} > static inline void kasan_free_pages(struct page *page, unsigned int order) {} > - > 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 size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; } > +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) {} > @@ -126,36 +239,33 @@ static inline void *kasan_init_slab_obj(struct kmem_cache *cache, > { > return (void *)object; > } > - > -static inline void *kasan_kmalloc_large(void *ptr, size_t size, gfp_t flags) > +static inline bool kasan_slab_free(struct kmem_cache *s, void *object, > + unsigned long ip) > { > - return ptr; > + return false; > } > -static inline void kasan_kfree_large(void *ptr, unsigned long ip) {} > -static inline void kasan_poison_kfree(void *ptr, unsigned long ip) {} > -static inline void *kasan_kmalloc(struct kmem_cache *s, const void *object, > - size_t size, gfp_t flags) > +static inline void *kasan_slab_alloc(struct kmem_cache *s, void *object, > + gfp_t flags) > { > - return (void *)object; > + return object; > } > -static inline void *kasan_krealloc(const void *object, size_t new_size, > - gfp_t flags) > +static inline void *kasan_kmalloc(struct kmem_cache *s, const void *object, > + size_t size, gfp_t flags) > { > return (void *)object; > } > > -static inline void *kasan_slab_alloc(struct kmem_cache *s, void *object, > - gfp_t flags) > +static inline void *kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags) > { > - return object; > + return (void *)ptr; > } > -static inline bool kasan_slab_free(struct kmem_cache *s, void *object, > - unsigned long ip) > +static inline void *kasan_krealloc(const void *object, size_t new_size, > + gfp_t flags) > { > - return false; > + return (void *)object; > } > - > -static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; } > +static inline void kasan_poison_kfree(void *ptr, unsigned long ip) {} > +static inline void kasan_kfree_large(void *ptr, unsigned long ip) {} > > #endif /* CONFIG_KASAN */ > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index a3cac68c737c..701e9d7666d6 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1412,22 +1412,36 @@ static inline bool cpupid_match_pid(struct task_struct *task, int cpupid) > #endif /* CONFIG_NUMA_BALANCING */ > > #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) > + > +#ifdef CONFIG_KASAN_HW_TAGS > +DECLARE_STATIC_KEY_FALSE(kasan_enabled); > +#else > +DECLARE_STATIC_KEY_TRUE(kasan_enabled); > +#endif > + > static inline u8 page_kasan_tag(const struct page *page) > { > - return (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK; > + if (static_branch_likely(&kasan_enabled)) > + return (page->flags >> KASAN_TAG_PGSHIFT) & KASAN_TAG_MASK; > + return 0xff; > } > > static inline void page_kasan_tag_set(struct page *page, u8 tag) > { > - page->flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT); > - page->flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT; > + if (static_branch_likely(&kasan_enabled)) { > + page->flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT); > + page->flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT; > + } > } > > static inline void page_kasan_tag_reset(struct page *page) > { > - page_kasan_tag_set(page, 0xff); > + if (static_branch_likely(&kasan_enabled)) > + page_kasan_tag_set(page, 0xff); > } > -#else > + > +#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ > + > static inline u8 page_kasan_tag(const struct page *page) > { > return 0xff; > @@ -1435,7 +1449,8 @@ static inline u8 page_kasan_tag(const struct page *page) > > static inline void page_kasan_tag_set(struct page *page, u8 tag) { } > static inline void page_kasan_tag_reset(struct page *page) { } > -#endif > + > +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ > > static inline struct zone *page_zone(const struct page *page) > { > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > index cc129ef62ab1..c5ec60e1a4d2 100644 > --- a/mm/kasan/common.c > +++ b/mm/kasan/common.c > @@ -81,7 +81,7 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark) > } > #endif /* CONFIG_KASAN_STACK */ > > -void kasan_alloc_pages(struct page *page, unsigned int order) > +void __kasan_alloc_pages(struct page *page, unsigned int order) > { > u8 tag; > unsigned long i; > @@ -95,7 +95,7 @@ void kasan_alloc_pages(struct page *page, unsigned int order) > kasan_unpoison_memory(page_address(page), PAGE_SIZE << order); > } > > -void kasan_free_pages(struct page *page, unsigned int order) > +void __kasan_free_pages(struct page *page, unsigned int order) > { > if (likely(!PageHighMem(page))) > kasan_poison_memory(page_address(page), > @@ -122,8 +122,8 @@ static inline unsigned int optimal_redzone(unsigned int object_size) > object_size <= (1 << 16) - 1024 ? 1024 : 2048; > } > > -void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > - slab_flags_t *flags) > +void __kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > + slab_flags_t *flags) > { > unsigned int orig_size = *size; > unsigned int redzone_size; > @@ -165,7 +165,7 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size, > *flags |= SLAB_KASAN; > } > > -size_t kasan_metadata_size(struct kmem_cache *cache) > +size_t __kasan_metadata_size(struct kmem_cache *cache) > { > if (static_branch_unlikely(&kasan_stack)) > return (cache->kasan_info.alloc_meta_offset ? > @@ -188,17 +188,17 @@ 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) > +void __kasan_unpoison_data(const void *addr, size_t size) > { > - kasan_unpoison_memory(address, size); > + kasan_unpoison_memory(addr, size); > } > > -void kasan_unpoison_slab(const void *ptr) > +void __kasan_unpoison_slab(const void *ptr) > { > kasan_unpoison_memory(ptr, __ksize(ptr)); > } > > -void kasan_poison_slab(struct page *page) > +void __kasan_poison_slab(struct page *page) > { > unsigned long i; > > @@ -208,12 +208,12 @@ void kasan_poison_slab(struct page *page) > KASAN_KMALLOC_REDZONE); > } > > -void kasan_unpoison_object_data(struct kmem_cache *cache, void *object) > +void __kasan_unpoison_object_data(struct kmem_cache *cache, void *object) > { > kasan_unpoison_memory(object, cache->object_size); > } > > -void kasan_poison_object_data(struct kmem_cache *cache, void *object) > +void __kasan_poison_object_data(struct kmem_cache *cache, void *object) > { > kasan_poison_memory(object, > round_up(cache->object_size, KASAN_GRANULE_SIZE), > @@ -266,7 +266,7 @@ static u8 assign_tag(struct kmem_cache *cache, const void *object, > #endif > } > > -void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, > +void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache, > const void *object) > { > struct kasan_alloc_meta *alloc_meta; > @@ -285,7 +285,7 @@ void * __must_check kasan_init_slab_obj(struct kmem_cache *cache, > return (void *)object; > } > > -static bool __kasan_slab_free(struct kmem_cache *cache, void *object, > +static bool ____kasan_slab_free(struct kmem_cache *cache, void *object, > unsigned long ip, bool quarantine) > { > u8 tag; > @@ -329,9 +329,9 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object, > return false; > } > > -bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) > +bool __kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip) > { > - return __kasan_slab_free(cache, object, ip, true); > + return ____kasan_slab_free(cache, object, ip, true); > } > > static void set_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags) > @@ -339,7 +339,7 @@ static void set_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags) > kasan_set_track(&kasan_get_alloc_meta(cache, object)->alloc_track, flags); > } > > -static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, > +static void *____kasan_kmalloc(struct kmem_cache *cache, const void *object, > size_t size, gfp_t flags, bool keep_tag) > { > unsigned long redzone_start; > @@ -371,20 +371,20 @@ static void *__kasan_kmalloc(struct kmem_cache *cache, const void *object, > return set_tag(object, tag); > } > > -void * __must_check kasan_slab_alloc(struct kmem_cache *cache, void *object, > - gfp_t flags) > +void * __must_check __kasan_slab_alloc(struct kmem_cache *cache, > + void *object, gfp_t flags) > { > - return __kasan_kmalloc(cache, object, cache->object_size, flags, false); > + return ____kasan_kmalloc(cache, object, cache->object_size, flags, false); > } > > -void * __must_check kasan_kmalloc(struct kmem_cache *cache, const void *object, > - size_t size, gfp_t flags) > +void * __must_check __kasan_kmalloc(struct kmem_cache *cache, const void *object, > + size_t size, gfp_t flags) > { > - return __kasan_kmalloc(cache, object, size, flags, true); > + return ____kasan_kmalloc(cache, object, size, flags, true); > } > -EXPORT_SYMBOL(kasan_kmalloc); > +EXPORT_SYMBOL(__kasan_kmalloc); > > -void * __must_check kasan_kmalloc_large(const void *ptr, size_t size, > +void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size, > gfp_t flags) > { > struct page *page; > @@ -409,7 +409,7 @@ void * __must_check kasan_kmalloc_large(const void *ptr, size_t size, > return (void *)ptr; > } > > -void * __must_check kasan_krealloc(const void *object, size_t size, gfp_t flags) > +void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flags) > { > struct page *page; > > @@ -419,13 +419,13 @@ void * __must_check kasan_krealloc(const void *object, size_t size, gfp_t flags) > page = virt_to_head_page(object); > > if (unlikely(!PageSlab(page))) > - return kasan_kmalloc_large(object, size, flags); > + return __kasan_kmalloc_large(object, size, flags); > else > - return __kasan_kmalloc(page->slab_cache, object, size, > + return ____kasan_kmalloc(page->slab_cache, object, size, > flags, true); > } > > -void kasan_poison_kfree(void *ptr, unsigned long ip) > +void __kasan_poison_kfree(void *ptr, unsigned long ip) > { > struct page *page; > > @@ -438,11 +438,11 @@ void kasan_poison_kfree(void *ptr, unsigned long ip) > } > kasan_poison_memory(ptr, page_size(page), KASAN_FREE_PAGE); > } else { > - __kasan_slab_free(page->slab_cache, ptr, ip, false); > + ____kasan_slab_free(page->slab_cache, ptr, ip, false); > } > } > > -void kasan_kfree_large(void *ptr, unsigned long ip) > +void __kasan_kfree_large(void *ptr, unsigned long ip) > { > if (ptr != page_address(virt_to_head_page(ptr))) > kasan_report_invalid_free(ptr, ip); > -- > 2.29.0.rc1.297.gfa9743e501-goog >
