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Message-ID: <CACT4Y+a8DFk_CqAV0JWSG57D-gQkSgEERYaHQwZAcPNUtZDvdQ@mail.gmail.com>
Date: Tue, 17 Nov 2020 11:56:36 +0100
From: Dmitry Vyukov <dvyukov@...gle.com>
To: Andrey Konovalov <andreyknvl@...gle.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Vincenzo Frascino <vincenzo.frascino@....com>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Alexander Potapenko <glider@...gle.com>,
Marco Elver <elver@...gle.com>,
Evgenii Stepanov <eugenis@...gle.com>,
Branislav Rankov <Branislav.Rankov@....com>,
Kevin Brodsky <kevin.brodsky@....com>,
kasan-dev <kasan-dev@...glegroups.com>,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
Linux-MM <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH mm v3 07/19] kasan: inline kasan_reset_tag for tag-based modes
On Fri, Nov 13, 2020 at 11:20 PM Andrey Konovalov <andreyknvl@...gle.com> 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@...gle.com>
> Reviewed-by: Marco Elver <elver@...gle.com>
Reviewed-by: Dmitry Vyukov <dvyukov@...gle.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(-)
>
> diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> index f2109bf0c5f9..1594177f86bb 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 fabd843eff3d..1ac4f435c679 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -180,14 +180,14 @@ 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)
> @@ -284,7 +284,7 @@ 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 (is_kfence_address(object))
> return false;
> diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c
> index 68e77363e58b..a34476764f1d 100644
> --- a/mm/kasan/hw_tags.c
> +++ b/mm/kasan/hw_tags.c
> @@ -31,18 +31,13 @@ void __init kasan_init_hw_tags(void)
> pr_info("KernelAddressSanitizer initialized\n");
> }
>
> -void *kasan_reset_tag(const void *addr)
> -{
> - return reset_tag(addr);
> -}
> -
> void poison_range(const void *address, size_t size, u8 value)
> {
> /* Skip KFENCE memory if called explicitly outside of sl*b. */
> if (is_kfence_address(address))
> return;
>
> - hw_set_mem_tag_range(reset_tag(address),
> + hw_set_mem_tag_range(kasan_reset_tag(address),
> round_up(size, KASAN_GRANULE_SIZE), value);
> }
>
> @@ -52,7 +47,7 @@ void unpoison_range(const void *address, size_t size)
> if (is_kfence_address(address))
> return;
>
> - 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 0eab7e4cecb8..5e8cd2080369 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -248,15 +248,11 @@ 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 df16bef0d810..76a0e3ae2049 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 d8a122f887a0..37153bd1c126 100644
> --- a/mm/kasan/shadow.c
> +++ b/mm/kasan/shadow.c
> @@ -82,7 +82,7 @@ void poison_range(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);
>
> /* Skip KFENCE memory if called explicitly outside of sl*b. */
> if (is_kfence_address(address))
> @@ -103,7 +103,7 @@ void unpoison_range(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);
>
> /*
> * Skip KFENCE memory if called explicitly outside of sl*b. Also note
> diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c
> index 6d7648cc3b98..e17de2619bbf 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);
> --
> 2.29.2.299.gdc1121823c-goog
>
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