On 1/30/21 4:52 PM, Vincenzo Frascino wrote: > This patchset implements the asynchronous mode support for ARMv8.5-A > Memory Tagging Extension (MTE), which is a debugging feature that allows > to detect with the help of the architecture the C and C++ programmatic > memory errors like buffer overflow, use-after-free, use-after-return, etc. > > MTE is built on top of the AArch64 v8.0 virtual address tagging TBI > (Top Byte Ignore) feature and allows a task to set a 4 bit tag on any > subset of its address space that is multiple of a 16 bytes granule. MTE > is based on a lock-key mechanism where the lock is the tag associated to > the physical memory and the key is the tag associated to the virtual > address. > When MTE is enabled and tags are set for ranges of address space of a task, > the PE will compare the tag related to the physical memory with the tag > related to the virtual address (tag check operation). Access to the memory > is granted only if the two tags match. In case of mismatch the PE will raise > an exception. > > The exception can be handled synchronously or asynchronously. When the > asynchronous mode is enabled: > - Upon fault the PE updates the TFSR_EL1 register. > - The kernel detects the change during one of the following: > - Context switching > - Return to user/EL0 > - Kernel entry from EL1 > - Kernel exit to EL1 > - If the register has been updated by the PE the kernel clears it and > reports the error. > > The series is based on linux-next/akpm. >
We are suspecting an issue with with the kernel access nofault functions triggering async faults that impacts Android init process. Please do not merge this series until this is sorted. > To simplify the testing a tree with the new patches on top has been made > available at [1]. > > [1] https://git.gitlab.arm.com/linux-arm/linux-vf.git mte/v10.async.akpm > > Changes: > -------- > v11: > - Added patch that disables KUNIT tests in async mode > v10: > - Rebase on the latest linux-next/akpm > - Address review comments. > v9: > - Rebase on the latest linux-next/akpm > - Address review comments. > v8: > - Address review comments. > v7: > - Fix a warning reported by kernel test robot. This > time for real. > v6: > - Drop patches that forbid KASAN KUNIT tests when async > mode is enabled. > - Fix a warning reported by kernel test robot. > - Address review comments. > v5: > - Rebase the series on linux-next/akpm. > - Forbid execution for KASAN KUNIT tests when async > mode is enabled. > - Dropped patch to inline mte_assign_mem_tag_range(). > - Address review comments. > v4: > - Added support for kasan.mode (sync/async) kernel > command line parameter. > - Addressed review comments. > v3: > - Exposed kasan_hw_tags_mode to convert the internal > KASAN represenetation. > - Added dsb() for kernel exit paths in arm64. > - Addressed review comments. > v2: > - Fixed a compilation issue reported by krobot. > - General cleanup. > > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: Catalin Marinas <catalin.mari...@arm.com> > Cc: Will Deacon <w...@kernel.org> > Cc: Dmitry Vyukov <dvyu...@google.com> > Cc: Andrey Ryabinin <aryabi...@virtuozzo.com> > Cc: Alexander Potapenko <gli...@google.com> > Cc: Marco Elver <el...@google.com> > Cc: Evgenii Stepanov <euge...@google.com> > Cc: Branislav Rankov <branislav.ran...@arm.com> > Cc: Andrey Konovalov <andreyk...@google.com> > Signed-off-by: Vincenzo Frascino <vincenzo.frasc...@arm.com> > > Andrey Konovalov (1): > kasan: don't run tests in async mode > > Vincenzo Frascino (4): > arm64: mte: Add asynchronous mode support > kasan: Add KASAN mode kernel parameter > kasan: Add report for async mode > arm64: mte: Enable async tag check fault > > Documentation/dev-tools/kasan.rst | 9 +++++ > arch/arm64/include/asm/memory.h | 3 +- > arch/arm64/include/asm/mte-kasan.h | 9 ++++- > arch/arm64/include/asm/mte.h | 32 ++++++++++++++++ > arch/arm64/kernel/entry-common.c | 6 +++ > arch/arm64/kernel/mte.c | 60 +++++++++++++++++++++++++++++- > include/linux/kasan.h | 6 +++ > lib/test_kasan.c | 6 ++- > mm/kasan/hw_tags.c | 51 ++++++++++++++++++++++++- > mm/kasan/kasan.h | 7 +++- > mm/kasan/report.c | 17 ++++++++- > 11 files changed, 196 insertions(+), 10 deletions(-) > -- Regards, Vincenzo