[PATCH v3 mm 00/13] kasan: optimizations and fixes for HW_TAGS

Andrey Konovalov
2021-02-05T19:33:25Z

This patchset makes the HW_TAGS mode more efficient, mostly by reworking
poisoning approaches and simplifying/inlining some internal helpers.

With this change, the overhead of HW_TAGS annotations excluding setting
and checking memory tags is ~3%. The performance impact caused by tags
will be unknown until we have hardware that supports MTE.

As a side-effect, this patchset speeds up generic KASAN by ~15%.

Changes v2->v3:
- Rebased onto mm.
- Add documentation update patch.

Changes v1->v2:
- Use EXPORT_SYMBOL_GPL() for arm64 symbols.
- Rename kmalloc bool flag argument to is_kmalloc.
- Make empty mte_set_mem_tag_range() return void.
- Fix build warning in 32-bit systems by using unsigned long instead
of u64 in WARN_ON() checks.
- Minor changes in comments and commit descriptions.
- Use kfence_ksize() before __ksize() to avoid crashes with KFENCE.
- Use inline instead of __always_inline.

Andrey Konovalov (13):
kasan, mm: don't save alloc stacks twice
kasan, mm: optimize kmalloc poisoning
kasan: optimize large kmalloc poisoning
kasan: clean up setting free info in kasan_slab_free
kasan: unify large kfree checks
kasan: rework krealloc tests
kasan, mm: fail krealloc on freed objects
kasan, mm: optimize krealloc poisoning
kasan: ensure poisoning size alignment
arm64: kasan: simplify and inline MTE functions
kasan: inline HW_TAGS helper functions
arm64: kasan: export MTE symbols for KASAN tests
kasan: clarify that only first bug is reported in HW_TAGS

Documentation/dev-tools/kasan.rst | 8 +-
arch/arm64/include/asm/cache.h | 1 -
arch/arm64/include/asm/kasan.h | 1 +
arch/arm64/include/asm/mte-def.h | 2 +
arch/arm64/include/asm/mte-kasan.h | 65 ++++++++--
arch/arm64/include/asm/mte.h | 2 -
arch/arm64/kernel/mte.c | 48 +-------
arch/arm64/lib/mte.S | 16 ---
include/linux/kasan.h | 25 ++--
lib/test_kasan.c | 111 +++++++++++++++--
mm/kasan/common.c | 187 ++++++++++++++++++++---------
mm/kasan/hw_tags.c | 2 +-
mm/kasan/kasan.h | 72 +++++++++--
mm/kasan/shadow.c | 53 ++++----
mm/slab_common.c | 18 ++-
mm/slub.c | 3 +-
16 files changed, 425 insertions(+), 189 deletions(-)

--
2.30.0.365.g02bc693789-goog