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    SubjectRe: [PATCH v2 07/20] kasan: inline kasan_reset_tag for tag-based modes
    On Tue, Nov 10, 2020 at 11:20PM +0100, Andrey Konovalov wrote:
    > Using kasan_reset_tag() currently results in a function call. As it's
    > called quite often from the allocator code, this leads to a noticeable
    > slowdown. Move it to include/linux/kasan.h and turn it into a static
    > inline function. Also remove the now unneeded reset_tag() internal KASAN
    > macro and use kasan_reset_tag() instead.
    >
    > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
    > Link: https://linux-review.googlesource.com/id/I4d2061acfe91d480a75df00b07c22d8494ef14b5
    > ---
    > include/linux/kasan.h | 5 ++++-
    > mm/kasan/common.c | 6 +++---
    > mm/kasan/hw_tags.c | 9 ++-------
    > mm/kasan/kasan.h | 4 ----
    > mm/kasan/report.c | 4 ++--
    > mm/kasan/report_hw_tags.c | 2 +-
    > mm/kasan/report_sw_tags.c | 4 ++--
    > mm/kasan/shadow.c | 4 ++--
    > mm/kasan/sw_tags.c | 9 ++-------
    > 9 files changed, 18 insertions(+), 29 deletions(-)

    Reviewed-by: Marco Elver <elver@google.com>

    > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
    > index b9b9db335d87..53c8e8b12fbc 100644
    > --- a/include/linux/kasan.h
    > +++ b/include/linux/kasan.h
    > @@ -193,7 +193,10 @@ static inline void kasan_record_aux_stack(void *ptr) {}
    >
    > #if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
    >
    > -void *kasan_reset_tag(const void *addr);
    > +static inline void *kasan_reset_tag(const void *addr)
    > +{
    > + return (void *)arch_kasan_reset_tag(addr);
    > +}
    >
    > bool kasan_report(unsigned long addr, size_t size,
    > bool is_write, unsigned long ip);
    > diff --git a/mm/kasan/common.c b/mm/kasan/common.c
    > index 9008fc6b0810..a266b90636a1 100644
    > --- a/mm/kasan/common.c
    > +++ b/mm/kasan/common.c
    > @@ -174,14 +174,14 @@ size_t kasan_metadata_size(struct kmem_cache *cache)
    > struct kasan_alloc_meta *kasan_get_alloc_meta(struct kmem_cache *cache,
    > const void *object)
    > {
    > - return (void *)reset_tag(object) + cache->kasan_info.alloc_meta_offset;
    > + return kasan_reset_tag(object) + cache->kasan_info.alloc_meta_offset;
    > }
    >
    > struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
    > const void *object)
    > {
    > BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
    > - return (void *)reset_tag(object) + cache->kasan_info.free_meta_offset;
    > + return kasan_reset_tag(object) + cache->kasan_info.free_meta_offset;
    > }
    >
    > void kasan_poison_slab(struct page *page)
    > @@ -278,7 +278,7 @@ static bool __kasan_slab_free(struct kmem_cache *cache, void *object,
    >
    > tag = get_tag(object);
    > tagged_object = object;
    > - object = reset_tag(object);
    > + object = kasan_reset_tag(object);
    >
    > if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) !=
    > object)) {
    > diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
    > index 70b88dd40cd8..49ea5f5c5643 100644
    > --- a/mm/kasan/hw_tags.c
    > +++ b/mm/kasan/hw_tags.c
    > @@ -30,20 +30,15 @@ void kasan_init_hw_tags(void)
    > pr_info("KernelAddressSanitizer initialized\n");
    > }
    >
    > -void *kasan_reset_tag(const void *addr)
    > -{
    > - return reset_tag(addr);
    > -}
    > -
    > void kasan_poison_memory(const void *address, size_t size, u8 value)
    > {
    > - hw_set_mem_tag_range(reset_tag(address),
    > + hw_set_mem_tag_range(kasan_reset_tag(address),
    > round_up(size, KASAN_GRANULE_SIZE), value);
    > }
    >
    > void kasan_unpoison_memory(const void *address, size_t size)
    > {
    > - hw_set_mem_tag_range(reset_tag(address),
    > + hw_set_mem_tag_range(kasan_reset_tag(address),
    > round_up(size, KASAN_GRANULE_SIZE), get_tag(address));
    > }
    >
    > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
    > index db8a7a508121..8a5501ef2339 100644
    > --- a/mm/kasan/kasan.h
    > +++ b/mm/kasan/kasan.h
    > @@ -246,15 +246,11 @@ static inline const void *arch_kasan_set_tag(const void *addr, u8 tag)
    > return addr;
    > }
    > #endif
    > -#ifndef arch_kasan_reset_tag
    > -#define arch_kasan_reset_tag(addr) ((void *)(addr))
    > -#endif
    > #ifndef arch_kasan_get_tag
    > #define arch_kasan_get_tag(addr) 0
    > #endif
    >
    > #define set_tag(addr, tag) ((void *)arch_kasan_set_tag((addr), (tag)))
    > -#define reset_tag(addr) ((void *)arch_kasan_reset_tag(addr))
    > #define get_tag(addr) arch_kasan_get_tag(addr)
    >
    > #ifdef CONFIG_KASAN_HW_TAGS
    > diff --git a/mm/kasan/report.c b/mm/kasan/report.c
    > index 0cac53a57c14..25ca66c99e48 100644
    > --- a/mm/kasan/report.c
    > +++ b/mm/kasan/report.c
    > @@ -328,7 +328,7 @@ void kasan_report_invalid_free(void *object, unsigned long ip)
    > unsigned long flags;
    > u8 tag = get_tag(object);
    >
    > - object = reset_tag(object);
    > + object = kasan_reset_tag(object);
    >
    > #if IS_ENABLED(CONFIG_KUNIT)
    > if (current->kunit_test)
    > @@ -361,7 +361,7 @@ static void __kasan_report(unsigned long addr, size_t size, bool is_write,
    > disable_trace_on_warning();
    >
    > tagged_addr = (void *)addr;
    > - untagged_addr = reset_tag(tagged_addr);
    > + untagged_addr = kasan_reset_tag(tagged_addr);
    >
    > info.access_addr = tagged_addr;
    > if (addr_has_metadata(untagged_addr))
    > diff --git a/mm/kasan/report_hw_tags.c b/mm/kasan/report_hw_tags.c
    > index da543eb832cd..57114f0e14d1 100644
    > --- a/mm/kasan/report_hw_tags.c
    > +++ b/mm/kasan/report_hw_tags.c
    > @@ -22,7 +22,7 @@ const char *get_bug_type(struct kasan_access_info *info)
    >
    > void *find_first_bad_addr(void *addr, size_t size)
    > {
    > - return reset_tag(addr);
    > + return kasan_reset_tag(addr);
    > }
    >
    > void metadata_fetch_row(char *buffer, void *row)
    > diff --git a/mm/kasan/report_sw_tags.c b/mm/kasan/report_sw_tags.c
    > index 317100fd95b9..7604b46239d4 100644
    > --- a/mm/kasan/report_sw_tags.c
    > +++ b/mm/kasan/report_sw_tags.c
    > @@ -41,7 +41,7 @@ const char *get_bug_type(struct kasan_access_info *info)
    > int i;
    >
    > tag = get_tag(info->access_addr);
    > - addr = reset_tag(info->access_addr);
    > + addr = kasan_reset_tag(info->access_addr);
    > page = kasan_addr_to_page(addr);
    > if (page && PageSlab(page)) {
    > cache = page->slab_cache;
    > @@ -72,7 +72,7 @@ const char *get_bug_type(struct kasan_access_info *info)
    > void *find_first_bad_addr(void *addr, size_t size)
    > {
    > u8 tag = get_tag(addr);
    > - void *p = reset_tag(addr);
    > + void *p = kasan_reset_tag(addr);
    > void *end = p + size;
    >
    > while (p < end && tag == *(u8 *)kasan_mem_to_shadow(p))
    > diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
    > index 616ac64c4a21..8e4fa9157a0b 100644
    > --- a/mm/kasan/shadow.c
    > +++ b/mm/kasan/shadow.c
    > @@ -81,7 +81,7 @@ void kasan_poison_memory(const void *address, size_t size, u8 value)
    > * some of the callers (e.g. kasan_poison_object_data) pass tagged
    > * addresses to this function.
    > */
    > - address = reset_tag(address);
    > + address = kasan_reset_tag(address);
    >
    > shadow_start = kasan_mem_to_shadow(address);
    > shadow_end = kasan_mem_to_shadow(address + size);
    > @@ -98,7 +98,7 @@ void kasan_unpoison_memory(const void *address, size_t size)
    > * some of the callers (e.g. kasan_unpoison_object_data) pass tagged
    > * addresses to this function.
    > */
    > - address = reset_tag(address);
    > + address = kasan_reset_tag(address);
    >
    > kasan_poison_memory(address, size, tag);
    >
    > diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
    > index 3bffb489b144..d1af6f6c6d12 100644
    > --- a/mm/kasan/sw_tags.c
    > +++ b/mm/kasan/sw_tags.c
    > @@ -67,11 +67,6 @@ u8 random_tag(void)
    > return (u8)(state % (KASAN_TAG_MAX + 1));
    > }
    >
    > -void *kasan_reset_tag(const void *addr)
    > -{
    > - return reset_tag(addr);
    > -}
    > -
    > bool check_memory_region(unsigned long addr, size_t size, bool write,
    > unsigned long ret_ip)
    > {
    > @@ -107,7 +102,7 @@ bool check_memory_region(unsigned long addr, size_t size, bool write,
    > if (tag == KASAN_TAG_KERNEL)
    > return true;
    >
    > - untagged_addr = reset_tag((const void *)addr);
    > + untagged_addr = kasan_reset_tag((const void *)addr);
    > if (unlikely(untagged_addr <
    > kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
    > return !kasan_report(addr, size, write, ret_ip);
    > @@ -126,7 +121,7 @@ bool check_memory_region(unsigned long addr, size_t size, bool write,
    > bool check_invalid_free(void *addr)
    > {
    > u8 tag = get_tag(addr);
    > - u8 shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(reset_tag(addr)));
    > + u8 shadow_byte = READ_ONCE(*(u8 *)kasan_mem_to_shadow(kasan_reset_tag(addr)));
    >
    > return (shadow_byte == KASAN_TAG_INVALID) ||
    > (tag != KASAN_TAG_KERNEL && tag != shadow_byte);
    > --
    > 2.29.2.222.g5d2a92d10f8-goog
    >

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