On Fri, Mar 12, 2021 at 03:24PM +0100, Andrey Konovalov wrote: > Update the "Implementation details" section for HW_TAGS KASAN: > > - Punctuation, readability, and other minor clean-ups. > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Reviewed-by: Marco Elver <elver@xxxxxxxxxx> > --- > Documentation/dev-tools/kasan.rst | 26 +++++++++++++------------- > 1 file changed, 13 insertions(+), 13 deletions(-) > > diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst > index 5873d80cc1fd..2744ae6347c6 100644 > --- a/Documentation/dev-tools/kasan.rst > +++ b/Documentation/dev-tools/kasan.rst > @@ -270,35 +270,35 @@ memory. > Hardware tag-based KASAN > ~~~~~~~~~~~~~~~~~~~~~~~~ > > -Hardware tag-based KASAN is similar to the software mode in concept, but uses > +Hardware tag-based KASAN is similar to the software mode in concept but uses > hardware memory tagging support instead of compiler instrumentation and > shadow memory. > > Hardware tag-based KASAN is currently only implemented for arm64 architecture > and based on both arm64 Memory Tagging Extension (MTE) introduced in ARMv8.5 > -Instruction Set Architecture, and Top Byte Ignore (TBI). > +Instruction Set Architecture and Top Byte Ignore (TBI). > > Special arm64 instructions are used to assign memory tags for each allocation. > Same tags are assigned to pointers to those allocations. On every memory > -access, hardware makes sure that tag of the memory that is being accessed is > -equal to tag of the pointer that is used to access this memory. In case of a > -tag mismatch a fault is generated and a report is printed. > +access, hardware makes sure that the tag of the memory that is being accessed is > +equal to the tag of the pointer that is used to access this memory. In case of a > +tag mismatch, a fault is generated, and a report is printed. > > Hardware tag-based KASAN uses 0xFF as a match-all pointer tag (accesses through > -pointers with 0xFF pointer tag aren't checked). The value 0xFE is currently > +pointers with the 0xFF pointer tag are not checked). The value 0xFE is currently > reserved to tag freed memory regions. > > -Hardware tag-based KASAN currently only supports tagging of > -kmem_cache_alloc/kmalloc and page_alloc memory. > +Hardware tag-based KASAN currently only supports tagging of slab and page_alloc > +memory. > > -If the hardware doesn't support MTE (pre ARMv8.5), hardware tag-based KASAN > -won't be enabled. In this case all boot parameters are ignored. > +If the hardware does not support MTE (pre ARMv8.5), hardware tag-based KASAN > +will not be enabled. In this case, all KASAN boot parameters are ignored. > > -Note, that enabling CONFIG_KASAN_HW_TAGS always results in in-kernel TBI being > -enabled. Even when kasan.mode=off is provided, or when the hardware doesn't > +Note that enabling CONFIG_KASAN_HW_TAGS always results in in-kernel TBI being > +enabled. Even when ``kasan.mode=off`` is provided or when the hardware does not > support MTE (but supports TBI). > > -Hardware tag-based KASAN only reports the first found bug. After that MTE tag > +Hardware tag-based KASAN only reports the first found bug. After that, MTE tag > checking gets disabled. > > Shadow memory > -- > 2.31.0.rc2.261.g7f71774620-goog >
