| Message ID | 20210129184905.29760-1-vincenzo.frascino@arm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | arm64: ARMv8.5-A: MTE: Add async mode support | expand |
On Fri, Jan 29, 2021 at 7:49 PM Vincenzo Frascino <vincenzo.frascino@arm.com> 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. > > 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: > -------- > v10: > - Rebase on the latest linux-next/akpm > - Address review comments. Thinking again about this: properly fixing that tracing issue is similar to fixing the issue with the tests. Let's do both as a part of this series. Here's a tree with the fixes. I've marked the ones that need to be squashed with "fix!". PTAL, and if the additions look good, please send v11 with them included. https://github.com/xairy/linux/commits/vf-v10.async.akpm-fixes
Hi Andrey, On 1/29/21 7:21 PM, Andrey Konovalov wrote: >> The series is based on linux-next/akpm. >> >> 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: >> -------- >> v10: >> - Rebase on the latest linux-next/akpm >> - Address review comments. > Thinking again about this: properly fixing that tracing issue is > similar to fixing the issue with the tests. Let's do both as a part of > this series. > > Here's a tree with the fixes. I've marked the ones that need to be > squashed with "fix!". PTAL, and if the additions look good, please > send v11 with them included. > > https://github.com/xairy/linux/commits/vf-v10.async.akpm-fixes I checked your code this morning and it seems OK (very similar to my proposal in logic but done in KASAN code as you anticipated). I am fine to add the changes to my patches but before then that I would like to conduct some testing, hence I will most likely have v11 sometimes this afternoon/evening UK time.
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. 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: -------- 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 <akpm@linux-foundation.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Marco Elver <elver@google.com> Cc: Evgenii Stepanov <eugenis@google.com> Cc: Branislav Rankov <Branislav.Rankov@arm.com> Cc: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> 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 | 2 +- mm/kasan/hw_tags.c | 32 +++++++++++++++- mm/kasan/kasan.h | 6 ++- mm/kasan/report.c | 18 ++++++++- 11 files changed, 173 insertions(+), 10 deletions(-)