Re: [PATCH -next v4 0/7]arm64: add machine check safe support

[Tong Tiangen]

Hi Mark, James, Robin, kindly ping...

Thanks.

在 2022/4/20 11:04, Tong Tiangen 写道:
> With the increase of memory capacity and density, the probability of
> memory error increases. The increasing size and density of server RAM
> in the data center and cloud have shown increased uncorrectable memory
> errors.
>
> Currently, the kernel has a mechanism to recover from hardware memory
> errors. This patchset provides an new recovery mechanism.
>
> For arm64, the hardware memory error handling is do_sea() which divided
> into two cases:
>   1. The user state consumed the memory errors, the solution is kill the
>      user process and isolate the error page.
>   2. The kernel state consumed the memory errors, the solution is panic.
>
> For case 2, Undifferentiated panic maybe not the optimal choice, it can be
> handled better, in some scenes, we can avoid panic, such as uaccess, if the
> uaccess fails due to memory error, only the user process will be affected,
> kill the user process and isolate the user page with hardware memory errors
> is a better choice.
>
> This patchset can be divided into three parts:
>   1. Patch 0/1/4    - make some minor fixes to the associated code.
>   2. Patch 3      - arm64 add support for machine check safe framework.
>   3. Pathc 5/6/7  - arm64 add uaccess and cow to machine check safe.
>
> Since V4:
>   1. According to Robin's suggestion, direct modify user_ldst and
>   user_ldp in asm-uaccess.h and modify mte.S.
>   2. Add new macro USER_MC in asm-uaccess.h, used in copy_from_user.S
>   and copy_to_user.S.
>   3. According to Robin's suggestion, using micro in copy_page_mc.S to
>   simplify code.
>   4. According to KeFeng's suggestion, modify powerpc code in patch1.
>   5. According to KeFeng's suggestion, modify mm/extable.c and some code
>   optimization.
>
> Since V3:
>   1. According to Mark's suggestion, all uaccess can be recovered due to
>      memory error.
>   2. Scenario pagecache reading is also supported as part of uaccess
>      (copy_to_user()) and duplication code problem is also solved.
>      Thanks for Robin's suggestion.
>   3. According Mark's suggestion, update commit message of patch 2/5.
>   4. According Borisllav's suggestion, update commit message of patch 1/5.
>
> Since V2:
>   1.Consistent with PPC/x86, Using CONFIG_ARCH_HAS_COPY_MC instead of
>     ARM64_UCE_KERNEL_RECOVERY.
>   2.Add two new scenes, cow and pagecache reading.
>   3.Fix two small bug(the first two patch).
>
> V1 in here:
> https://lore.kernel.org/lkml/20220323033705.3966643-1-tongtiangen@xxxxxxxxxx/
>
> Robin Murphy (1):
>    arm64: mte: Clean up user tag accessors
>
> Tong Tiangen (6):
>    x86, powerpc: fix function define in copy_mc_to_user
>    arm64: fix types in copy_highpage()
>    arm64: add support for machine check error safe
>    arm64: add copy_{to, from}_user to machine check safe
>    arm64: add {get, put}_user to machine check safe
>    arm64: add cow to machine check safe
>
>   arch/arm64/Kconfig                   |  1 +
>   arch/arm64/include/asm/asm-extable.h | 33 +++++++++++
>   arch/arm64/include/asm/asm-uaccess.h | 15 +++--
>   arch/arm64/include/asm/extable.h     |  1 +
>   arch/arm64/include/asm/page.h        | 10 ++++
>   arch/arm64/include/asm/uaccess.h     |  4 +-
>   arch/arm64/lib/Makefile              |  2 +
>   arch/arm64/lib/copy_from_user.S      | 18 +++---
>   arch/arm64/lib/copy_page_mc.S        | 86 ++++++++++++++++++++++++++++
>   arch/arm64/lib/copy_to_user.S        | 18 +++---
>   arch/arm64/lib/mte.S                 |  4 +-
>   arch/arm64/mm/copypage.c             | 36 ++++++++++--
>   arch/arm64/mm/extable.c              | 33 +++++++++++
>   arch/arm64/mm/fault.c                | 27 ++++++++-
>   arch/powerpc/include/asm/uaccess.h   |  1 +
>   arch/x86/include/asm/uaccess.h       |  1 +
>   include/linux/highmem.h              |  8 +++
>   include/linux/uaccess.h              |  9 +++
>   mm/memory.c                          |  2 +-
>   19 files changed, 278 insertions(+), 31 deletions(-)
>   create mode 100644 arch/arm64/lib/copy_page_mc.S