This series is initially targeted at the folks doing filesystems on top of NVDIMMs. They really want to be able to return -EIO when there is a h/w error (just like spinning rust, and SSD does). I plan to use the same infrastructure in parts 1&2 to write a machine check aware "copy_from_user()" that will SIGBUS the calling application when a syscall touches poison in user space (just like we do when the application touches the poison itself). Changes V2-V3: Andy: Don't hack "regs->ax = BIT(63) | addr;" in the machine check handler. Now have better fixup code that computes the number of remaining bytes (just like page-fault fixup). Andy: #define for BIT(63). Done, plus couple of extra macros using it. Boris: Don't clutter up generic code (like mm/extable.c) with this. I moved everything under arch/x86 (the asm-generic change is a more generic #define). Boris: Dependencies for CONFIG_MCE_KERNEL_RECOVERY are too generic. I made it a real menu item with default "n". Dan Williams will use "select MCE_KERNEL_RECOVERY" from his persistent filesystem code. Boris: Simplify conditionals in mce.c by moving tolerant/kill_it checks earlier, with a skip to end if they aren't set. Boris: Miscellaneous grammar/punctuation. Fixed. Boris: Don't leak spurious __start_mcextable symbols into kernels that didn't configure MCE_KERNEL_RECOVERY. Done. Tony: New code doesn't belong in user_copy_64.S/uaccess*.h. Moved to new .S/.h files Elliott:Cacheing behavior non-optimal. Could use movntdqa, vmovntdqa or vmovntdqa on source addresses. I didn't fix this yet. Think of the current mcsafe_memcpy() as the first of several functions. This one is useful for small copies (meta-data) where the overhead of saving SSE/AVX state isn't justified. Changes V1->V2: 0-day: Reported build errors and warnings on 32-bit systems. Fixed 0-day: Reported bloat to tinyconfig. Fixed Boris: Suggestions to use extra macros to reduce code duplication in _ASM_*EXTABLE. Done Boris: Re-write "tolerant==3" check to reduce indentation level. See below. Andy: Check IP is valid before searching kernel exception tables. Done. Andy: Explain use of BIT(63) on return value from mcsafe_memcpy(). Done (added decode macros). Andy: Untangle mess of code in tail of do_machine_check() to make it clear what is going on (e.g. that we only enter the ist_begin_non_atomic() if we were called from user code, not from kernel!). Done. Tony Luck (3): x86, ras: Add new infrastructure for machine check fixup tables x86, ras: Extend machine check recovery code to annotated ring0 areas x86, ras: Add mcsafe_memcpy() function to recover from machine checks arch/x86/Kconfig | 10 +++ arch/x86/include/asm/asm.h | 10 ++- arch/x86/include/asm/mce.h | 14 +++ arch/x86/include/asm/mcsafe_copy.h | 11 +++ arch/x86/kernel/cpu/mcheck/mce-severity.c | 21 ++++- arch/x86/kernel/cpu/mcheck/mce.c | 86 +++++++++++------- arch/x86/kernel/vmlinux.lds.S | 6 +- arch/x86/kernel/x8664_ksyms_64.c | 5 ++ arch/x86/lib/Makefile | 1 + arch/x86/lib/mcsafe_copy.S | 142 ++++++++++++++++++++++++++++++ arch/x86/mm/extable.c | 19 ++++ include/asm-generic/vmlinux.lds.h | 12 +-- 12 files changed, 293 insertions(+), 44 deletions(-) create mode 100644 arch/x86/include/asm/mcsafe_copy.h create mode 100644 arch/x86/lib/mcsafe_copy.S -- 2.1.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>