Changes since v1: - Rename memcpy_mcsafe() to copy_safe() since the x86-machine-check specifics have already been de-emphasized in a previous commit and are further de-emphasized by these changes. (Linus) - Move copy_safe() out-of-line since it no longer reverts to plain memcpy (Linus) - Move copy_safe() to its own stand-alone compilation unit where it no longer entangles with arch/x86/lib/memcpy_64.S. This also allows perf to stop tracking ongoing updates to that file due to copy_safe() updates. (Linus) - Move the PowerPC implementation over to the new name. [1]: http://lore.kernel.org/r/158654083112.1572482.8944305411228188871.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx --- The primary motivation to go touch memcpy_mcsafe() is that the existing benefit of doing slow and careful copies is obviated on newer CPUs. That fact solves the problem of needing to detect machine-check recovery capability. Now the old "mcsafe_key" opt-in to careful copying can be made an opt-out from the default fast copy implementation. The discussion with Linus further made clear that this facility had already lost its x86-machine-check specificity starting with commit 2c89130a56a ("x86/asm/memcpy_mcsafe: Add write-protection-fault handling"). The new changes to not require a "careful copy" further de-emphasizes the role that x86-MCA plays in the implementation to just one more source of recoverable trap during the operation. With the above realizations the name "mcsafe" is no longer accurate and copy_safe() is proposed as its replacement. x86 grows a copy_safe_fast() implementation as a default implementation that is independent of detecting the presence of x86-MCA. --- Dan Williams (2): copy_safe: Rename memcpy_mcsafe() to copy_safe() x86/copy_safe: Introduce copy_safe_fast() arch/powerpc/Kconfig | 2 arch/powerpc/include/asm/string.h | 2 arch/powerpc/include/asm/uaccess.h | 4 arch/powerpc/lib/Makefile | 2 arch/powerpc/lib/copy_safe.S | 4 arch/x86/Kconfig | 2 arch/x86/Kconfig.debug | 2 arch/x86/include/asm/copy_safe.h | 18 ++ arch/x86/include/asm/copy_safe_test.h | 75 +++++++++ arch/x86/include/asm/mcsafe_test.h | 75 --------- arch/x86/include/asm/string_64.h | 32 ---- arch/x86/include/asm/uaccess_64.h | 21 --- arch/x86/kernel/cpu/mce/core.c | 9 - arch/x86/kernel/quirks.c | 10 - arch/x86/lib/Makefile | 1 arch/x86/lib/copy_safe.c | 66 ++++++++ arch/x86/lib/copy_safe_64.S | 163 ++++++++++++++++++++ arch/x86/lib/memcpy_64.S | 115 -------------- arch/x86/lib/usercopy_64.c | 21 --- drivers/md/dm-writecache.c | 12 + drivers/nvdimm/claim.c | 2 drivers/nvdimm/pmem.c | 6 - include/linux/string.h | 17 +- include/linux/uio.h | 10 + lib/Kconfig | 2 lib/iov_iter.c | 36 ++-- tools/arch/x86/include/asm/copy_safe_test.h | 13 ++ tools/arch/x86/include/asm/mcsafe_test.h | 13 -- tools/arch/x86/lib/memcpy_64.S | 115 -------------- tools/objtool/check.c | 5 - tools/perf/bench/Build | 1 tools/perf/bench/mem-memcpy-x86-64-lib.c | 24 --- tools/testing/nvdimm/test/nfit.c | 49 +++--- .../testing/selftests/powerpc/copyloops/.gitignore | 2 tools/testing/selftests/powerpc/copyloops/Makefile | 6 - .../selftests/powerpc/copyloops/copy_safe.S | 0 36 files changed, 429 insertions(+), 508 deletions(-) rename arch/powerpc/lib/{memcpy_mcsafe_64.S => copy_safe.S} (98%) create mode 100644 arch/x86/include/asm/copy_safe.h create mode 100644 arch/x86/include/asm/copy_safe_test.h delete mode 100644 arch/x86/include/asm/mcsafe_test.h create mode 100644 arch/x86/lib/copy_safe.c create mode 100644 arch/x86/lib/copy_safe_64.S create mode 100644 tools/arch/x86/include/asm/copy_safe_test.h delete mode 100644 tools/arch/x86/include/asm/mcsafe_test.h delete mode 100644 tools/perf/bench/mem-memcpy-x86-64-lib.c rename tools/testing/selftests/powerpc/copyloops/{memcpy_mcsafe_64.S => copy_safe.S} (100%) base-commit: b8dcd632c06b8706d22934f9bf9bf16a42b1ecc7
