diff options
| author | Vincenzo Frascino <vincenzo.frascino@arm.com> | 2021-10-06 16:47:51 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2021-10-07 09:30:24 +0100 |
| commit | 2d27e585147395316289c63efc932984675c65c2 (patch) | |
| tree | 5d82a14908745fa469138792dc6b212859bacdfd /Documentation/dev-tools/kasan.rst | |
| parent | ec0288369f0cc6d85837a18f1c4c65451c94477b (diff) | |
kasan: Extend KASAN mode kernel parameter
Architectures supported by KASAN_HW_TAGS can provide an asymmetric mode
of execution. On an MTE enabled arm64 hw for example this can be
identified with the asymmetric tagging mode of execution. In particular,
when such a mode is present, the CPU triggers a fault on a tag mismatch
during a load operation and asynchronously updates a register when a tag
mismatch is detected during a store operation.
Extend the KASAN HW execution mode kernel command line parameter to
support asymmetric mode.
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/r/20211006154751.4463-6-vincenzo.frascino@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'Documentation/dev-tools/kasan.rst')
| -rw-r--r-- | Documentation/dev-tools/kasan.rst | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 21dc03bc10a4..8089c559d339 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -194,14 +194,17 @@ additional boot parameters that allow disabling KASAN or controlling features: - ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``). -- ``kasan.mode=sync`` or ``=async`` controls whether KASAN is configured in - synchronous or asynchronous mode of execution (default: ``sync``). +- ``kasan.mode=sync``, ``=async`` or ``=asymm`` controls whether KASAN + is configured in synchronous, asynchronous or asymmetric mode of + execution (default: ``sync``). Synchronous mode: a bad access is detected immediately when a tag check fault occurs. Asynchronous mode: a bad access detection is delayed. When a tag check fault occurs, the information is stored in hardware (in the TFSR_EL1 register for arm64). The kernel periodically checks the hardware and only reports tag faults during these checks. + Asymmetric mode: a bad access is detected synchronously on reads and + asynchronously on writes. - ``kasan.stacktrace=off`` or ``=on`` disables or enables alloc and free stack traces collection (default: ``on``). |