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 scenarios, 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.
Tong Tiangen (14): Revert "arm64: ras: copy_from_user scenario support uce kernel recovery" Revert "arm64: config: enable CONFIG_ARM64_UCE_KERNEL_RECOVERY" uaccess: add generic fallback version of copy_mc_to_user() arm64: extable: add new extable type "__mc_ex_table" arm64: add support for machine check error safe arm64: copy_form/to_user support machine check safe arm64: get/put_user support machine check safe arm64: add cow to machine check safe arm64: introduce copy_mc_to_kernel() implementation arm64: add dump_user_range() to machine check safe arm64: add machine check safe sysctl interface arm64/__mc_ex_table: search_module_mc_extables should not use num_exentries arm64/__mc_ex_table: fix compile error when CONFIG_ARCH_HAS_COPY_MC=n arm64/__mc_ex_table: fix __mc_ex_table do_sort() issue
Documentation/admin-guide/sysctl/kernel.rst | 38 ++-- arch/arm64/Kconfig | 14 +- arch/arm64/configs/openeuler_defconfig | 1 - arch/arm64/include/asm/asm-uaccess.h | 5 + arch/arm64/include/asm/assembler.h | 26 ++- arch/arm64/include/asm/exception.h | 13 -- arch/arm64/include/asm/extable.h | 1 + arch/arm64/include/asm/mte.h | 4 + arch/arm64/include/asm/page.h | 10 + arch/arm64/include/asm/processor.h | 2 + arch/arm64/include/asm/string.h | 5 + arch/arm64/include/asm/uaccess.h | 70 +++++-- arch/arm64/lib/Makefile | 10 +- arch/arm64/lib/copy_from_user.S | 19 +- arch/arm64/lib/copy_page_mc.S | 80 ++++++++ arch/arm64/lib/copy_to_user.S | 10 +- arch/arm64/lib/memcpy_mc.S | 73 ++++++++ arch/arm64/lib/mte.S | 19 ++ arch/arm64/mm/Makefile | 2 - arch/arm64/mm/copypage.c | 37 +++- arch/arm64/mm/extable.c | 12 ++ arch/arm64/mm/fault.c | 36 +++- arch/arm64/mm/uce_kernel_recovery.c | 198 -------------------- arch/powerpc/include/asm/uaccess.h | 1 + arch/x86/include/asm/uaccess.h | 1 + fs/coredump.c | 2 + include/asm-generic/vmlinux.lds.h | 19 +- include/linux/extable.h | 23 +++ include/linux/highmem.h | 8 + include/linux/module.h | 11 ++ include/linux/sched.h | 1 + include/linux/uaccess.h | 9 + kernel/extable.c | 29 +++ kernel/module.c | 38 ++++ kernel/sysctl.c | 11 ++ lib/iov_iter.c | 12 +- mm/memory.c | 2 +- scripts/sorttable.h | 27 +++ 38 files changed, 583 insertions(+), 296 deletions(-) create mode 100644 arch/arm64/lib/copy_page_mc.S create mode 100644 arch/arm64/lib/memcpy_mc.S delete mode 100644 arch/arm64/mm/uce_kernel_recovery.c