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
--
2.25.1
