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    Subject[PATCH v2 10/20] kasan: inline and rename kasan_unpoison_memory
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    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
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