| Message ID | 20210118183033.41764-1-vincenzo.frascino@arm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | arm64: ARMv8.5-A: MTE: Add async mode support | expand |
On Mon, Jan 18, 2021 at 7:30 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 contains as well an optimization to mte_assign_mem_tag_range(). > > The series is based on linux 5.11-rc3. > > 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 Hi Vincenzo, This change has multiple conflicts with the KASAN testing patches that are currently in the mm tree. If Andrew decides to send all of them during RC, then this should be good to go through arm64. Otherwise, I guess this will need to go through mm as well. So you probably need to rebase this on top of those patches in any case. Thanks!
Hi Andrey, On 1/19/21 6:09 PM, Andrey Konovalov wrote: > Hi Vincenzo, > > This change has multiple conflicts with the KASAN testing patches that > are currently in the mm tree. If Andrew decides to send all of them > during RC, then this should be good to go through arm64. Otherwise, I > guess this will need to go through mm as well. So you probably need to > rebase this on top of those patches in any case. > Could you please let me know on which tree do you want me to rebase my patches? I almost completed the requested changes. Thank you! > Thanks!
On Thu, Jan 21, 2021 at 12:31 PM Vincenzo Frascino <vincenzo.frascino@arm.com> wrote: > > Hi Andrey, > > On 1/19/21 6:09 PM, Andrey Konovalov wrote: > > Hi Vincenzo, > > > > This change has multiple conflicts with the KASAN testing patches that > > are currently in the mm tree. If Andrew decides to send all of them > > during RC, then this should be good to go through arm64. Otherwise, I > > guess this will need to go through mm as well. So you probably need to > > rebase this on top of those patches in any case. > > > > Could you please let me know on which tree do you want me to rebase my patches? > I almost completed the requested changes. linux-next/akpm should work. Thanks!
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 contains as well an optimization to mte_assign_mem_tag_range(). The series is based on linux 5.11-rc3. 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 Changes: -------- 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: 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 (5): 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 arm64: mte: Inline mte_assign_mem_tag_range() Documentation/dev-tools/kasan.rst | 3 ++ arch/arm64/include/asm/memory.h | 3 +- arch/arm64/include/asm/mte-kasan.h | 9 ++++- arch/arm64/include/asm/mte.h | 58 ++++++++++++++++++++++++++- arch/arm64/kernel/entry-common.c | 6 +++ arch/arm64/kernel/mte.c | 63 +++++++++++++++++++++++++++++- arch/arm64/lib/mte.S | 15 ------- include/linux/kasan.h | 3 ++ mm/kasan/hw_tags.c | 31 ++++++++++++++- mm/kasan/kasan.h | 3 +- mm/kasan/report.c | 16 +++++++- 11 files changed, 185 insertions(+), 25 deletions(-)