[PATCH v9 0/4] arm64: ARMv8.5-A: MTE: Add async mode support

[Andrey Konovalov]

On Tue, Jan 26, 2021 at 2:46 PM Vincenzo Frascino
<vincenzo.frascino at 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
>
> Cc: Andrew Morton <akpm at linux-foundation.org>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Will Deacon <will at kernel.org>
> Cc: Dmitry Vyukov <dvyukov at google.com>
> Cc: Andrey Ryabinin <aryabinin at virtuozzo.com>
> Cc: Alexander Potapenko <glider at google.com>
> Cc: Marco Elver <elver at google.com>
> Cc: Evgenii Stepanov <eugenis at google.com>
> Cc: Branislav Rankov <Branislav.Rankov at arm.com>
> Cc: Andrey Konovalov <andreyknvl at google.com>
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino at arm.com>

Tested-by: Andrey Konovalov <andreyknvl at google.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

Andrew, could you pick this up into mm? The whole series will need to
go through mm due to dependencies on the patches that are already
there.