From: Dan Williams <dan.j.williams@intel.com> To: mingo@redhat.com Cc: Tony Luck <tony.luck@intel.com>, Peter Zijlstra <peterz@infradead.org>, Linus Torvalds <torvalds@linux-foundation.org>, Alexander Viro <viro@zeniv.linux.org.uk>, Borislav Petkov <bp@alien8.de>, stable@vger.kernel.org, x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>, tglx@linutronix.de, Andy Lutomirski <luto@kernel.org>, Paul Mackerras <paulus@samba.org>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Erwin Tsaur <erwin.tsaur@intel.com>, Michael Ellerman <mpe@ellerman.id.au>, Mikulas Patocka <mpatocka@redhat.com>, Arnaldo Carvalho de Melo <acme@kernel.org>, 0day robot <lkp@intel.com>, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, jack@suse.cz Subject: [PATCH v9 0/2] Renovate memcpy_mcsafe with copy_mc_to_{user, kernel} Date: Wed, 23 Sep 2020 09:41:26 -0700 [thread overview] Message-ID: <160087928642.3520.17063139768910633998.stgit@dwillia2-desk3.amr.corp.intel.com> (raw) Changes since v8 [1]: - Rebase on v5.9-rc6 - Fix a performance regression in the x86 copy_mc_to_user() implementation that was duplicating copies in the "fragile" case. - Refreshed the cover letter. [1]: http://lore.kernel.org/r/159630255616.3143511.18110575960499749012.stgit@dwillia2-desk3.amr.corp.intel.com --- The motivations to go rework memcpy_mcsafe() are that the benefit of doing slow and careful copies is obviated on newer CPUs, and that the current opt-in list of cpus to instrument recovery is broken relative to those cpus. There is no need to keep an opt-in list up to date on an ongoing basis if pmem/dax operations are instrumented for recovery by default. With recovery enabled by default the old "mcsafe_key" opt-in to careful copying can be made a "fragile" opt-out. Where the "fragile" list takes steps to not consume poison across cachelines. The discussion with Linus made clear that the current "_mcsafe" suffix was imprecise to a fault. The operations that are needed by pmem/dax are to copy from a source address that might throw #MC to a destination that may write-fault, if it is a user page. So copy_to_user_mcsafe() becomes copy_mc_to_user() to indicate the separate precautions taken on source and destination. copy_mc_to_kernel() is introduced as a version that does not expect write-faults on the destination, but is still prepared to abort with an error code upon taking #MC. These patches have received a kbuild-robot build success notification across 114 configs, the rebase to v5.9-rc6 did not encounter any conflicts, and the merge with tip/master is conflict-free. --- Dan Williams (2): x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user,kernel}() x86/copy_mc: Introduce copy_mc_generic() arch/powerpc/Kconfig | 2 arch/powerpc/include/asm/string.h | 2 arch/powerpc/include/asm/uaccess.h | 40 +++-- arch/powerpc/lib/Makefile | 2 arch/powerpc/lib/copy_mc_64.S | 4 arch/x86/Kconfig | 2 arch/x86/Kconfig.debug | 2 arch/x86/include/asm/copy_mc_test.h | 75 +++++++++ arch/x86/include/asm/mcsafe_test.h | 75 --------- arch/x86/include/asm/string_64.h | 32 ---- arch/x86/include/asm/uaccess.h | 21 +++ arch/x86/include/asm/uaccess_64.h | 20 -- arch/x86/kernel/cpu/mce/core.c | 8 - arch/x86/kernel/quirks.c | 9 - arch/x86/lib/Makefile | 1 arch/x86/lib/copy_mc.c | 65 ++++++++ arch/x86/lib/copy_mc_64.S | 165 ++++++++++++++++++++ arch/x86/lib/memcpy_64.S | 115 -------------- arch/x86/lib/usercopy_64.c | 21 --- drivers/md/dm-writecache.c | 15 +- drivers/nvdimm/claim.c | 2 drivers/nvdimm/pmem.c | 6 - include/linux/string.h | 9 - include/linux/uaccess.h | 9 + include/linux/uio.h | 10 + lib/Kconfig | 7 + lib/iov_iter.c | 43 +++-- 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 | 48 +++--- .../testing/selftests/powerpc/copyloops/.gitignore | 2 tools/testing/selftests/powerpc/copyloops/Makefile | 6 - .../selftests/powerpc/copyloops/copy_mc_64.S | 1 .../selftests/powerpc/copyloops/memcpy_mcsafe_64.S | 1 37 files changed, 452 insertions(+), 526 deletions(-) rename arch/powerpc/lib/{memcpy_mcsafe_64.S => copy_mc_64.S} (98%) create mode 100644 arch/x86/include/asm/copy_mc_test.h delete mode 100644 arch/x86/include/asm/mcsafe_test.h create mode 100644 arch/x86/lib/copy_mc.c create mode 100644 arch/x86/lib/copy_mc_64.S delete mode 100644 tools/arch/x86/include/asm/mcsafe_test.h delete mode 100644 tools/perf/bench/mem-memcpy-x86-64-lib.c create mode 120000 tools/testing/selftests/powerpc/copyloops/copy_mc_64.S delete mode 120000 tools/testing/selftests/powerpc/copyloops/memcpy_mcsafe_64.S base-commit: ba4f184e126b751d1bffad5897f263108befc780 _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org
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From: Dan Williams <dan.j.williams@intel.com> To: mingo@redhat.com Cc: Tony Luck <tony.luck@intel.com>, Vivek Goyal <vgoyal@redhat.com>, Peter Zijlstra <peterz@infradead.org>, Linus Torvalds <torvalds@linux-foundation.org>, Alexander Viro <viro@zeniv.linux.org.uk>, Borislav Petkov <bp@alien8.de>, stable@vger.kernel.org, x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>, Andy Lutomirski <luto@kernel.org>, Paul Mackerras <paulus@samba.org>, Benjamin Herrenschmidt <benh@kernel.crashing.org>, Erwin Tsaur <erwin.tsaur@intel.com>, Michael Ellerman <mpe@ellerman.id.au>, Mikulas Patocka <mpatocka@redhat.com>, Arnaldo Carvalho de Melo <acme@kernel.org>, 0day robot <lkp@intel.com>, tglx@linutronix.de, x86@kernel.org, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org, jack@suse.cz Subject: [PATCH v9 0/2] Renovate memcpy_mcsafe with copy_mc_to_{user, kernel} Date: Wed, 23 Sep 2020 09:41:26 -0700 [thread overview] Message-ID: <160087928642.3520.17063139768910633998.stgit@dwillia2-desk3.amr.corp.intel.com> (raw) Changes since v8 [1]: - Rebase on v5.9-rc6 - Fix a performance regression in the x86 copy_mc_to_user() implementation that was duplicating copies in the "fragile" case. - Refreshed the cover letter. [1]: http://lore.kernel.org/r/159630255616.3143511.18110575960499749012.stgit@dwillia2-desk3.amr.corp.intel.com --- The motivations to go rework memcpy_mcsafe() are that the benefit of doing slow and careful copies is obviated on newer CPUs, and that the current opt-in list of cpus to instrument recovery is broken relative to those cpus. There is no need to keep an opt-in list up to date on an ongoing basis if pmem/dax operations are instrumented for recovery by default. With recovery enabled by default the old "mcsafe_key" opt-in to careful copying can be made a "fragile" opt-out. Where the "fragile" list takes steps to not consume poison across cachelines. The discussion with Linus made clear that the current "_mcsafe" suffix was imprecise to a fault. The operations that are needed by pmem/dax are to copy from a source address that might throw #MC to a destination that may write-fault, if it is a user page. So copy_to_user_mcsafe() becomes copy_mc_to_user() to indicate the separate precautions taken on source and destination. copy_mc_to_kernel() is introduced as a version that does not expect write-faults on the destination, but is still prepared to abort with an error code upon taking #MC. These patches have received a kbuild-robot build success notification across 114 configs, the rebase to v5.9-rc6 did not encounter any conflicts, and the merge with tip/master is conflict-free. --- Dan Williams (2): x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user,kernel}() x86/copy_mc: Introduce copy_mc_generic() arch/powerpc/Kconfig | 2 arch/powerpc/include/asm/string.h | 2 arch/powerpc/include/asm/uaccess.h | 40 +++-- arch/powerpc/lib/Makefile | 2 arch/powerpc/lib/copy_mc_64.S | 4 arch/x86/Kconfig | 2 arch/x86/Kconfig.debug | 2 arch/x86/include/asm/copy_mc_test.h | 75 +++++++++ arch/x86/include/asm/mcsafe_test.h | 75 --------- arch/x86/include/asm/string_64.h | 32 ---- arch/x86/include/asm/uaccess.h | 21 +++ arch/x86/include/asm/uaccess_64.h | 20 -- arch/x86/kernel/cpu/mce/core.c | 8 - arch/x86/kernel/quirks.c | 9 - arch/x86/lib/Makefile | 1 arch/x86/lib/copy_mc.c | 65 ++++++++ arch/x86/lib/copy_mc_64.S | 165 ++++++++++++++++++++ arch/x86/lib/memcpy_64.S | 115 -------------- arch/x86/lib/usercopy_64.c | 21 --- drivers/md/dm-writecache.c | 15 +- drivers/nvdimm/claim.c | 2 drivers/nvdimm/pmem.c | 6 - include/linux/string.h | 9 - include/linux/uaccess.h | 9 + include/linux/uio.h | 10 + lib/Kconfig | 7 + lib/iov_iter.c | 43 +++-- 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 | 48 +++--- .../testing/selftests/powerpc/copyloops/.gitignore | 2 tools/testing/selftests/powerpc/copyloops/Makefile | 6 - .../selftests/powerpc/copyloops/copy_mc_64.S | 1 .../selftests/powerpc/copyloops/memcpy_mcsafe_64.S | 1 37 files changed, 452 insertions(+), 526 deletions(-) rename arch/powerpc/lib/{memcpy_mcsafe_64.S => copy_mc_64.S} (98%) create mode 100644 arch/x86/include/asm/copy_mc_test.h delete mode 100644 arch/x86/include/asm/mcsafe_test.h create mode 100644 arch/x86/lib/copy_mc.c create mode 100644 arch/x86/lib/copy_mc_64.S delete mode 100644 tools/arch/x86/include/asm/mcsafe_test.h delete mode 100644 tools/perf/bench/mem-memcpy-x86-64-lib.c create mode 120000 tools/testing/selftests/powerpc/copyloops/copy_mc_64.S delete mode 120000 tools/testing/selftests/powerpc/copyloops/memcpy_mcsafe_64.S base-commit: ba4f184e126b751d1bffad5897f263108befc780
next reply other threads:[~2020-09-23 16:59 UTC|newest] Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-09-23 16:41 Dan Williams [this message] 2020-09-23 16:41 ` [PATCH v9 0/2] Renovate memcpy_mcsafe with copy_mc_to_{user, kernel} Dan Williams 2020-09-23 16:41 ` [PATCH v9 1/2] x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}() Dan Williams 2020-09-23 16:41 ` Dan Williams 2020-09-29 10:25 ` Borislav Petkov 2020-09-29 10:25 ` Borislav Petkov 2020-09-30 16:13 ` Dan Williams 2020-09-30 16:13 ` Dan Williams 2020-09-23 16:42 ` [PATCH v9 2/2] x86/copy_mc: Introduce copy_mc_generic() Dan Williams 2020-09-23 16:42 ` Dan Williams 2020-09-29 22:32 ` [PATCH v9 0/2] Renovate memcpy_mcsafe with copy_mc_to_{user, kernel} Dan Williams 2020-09-29 22:32 ` Dan Williams 2020-09-30 5:04 ` Borislav Petkov 2020-09-30 5:04 ` Borislav Petkov 2020-09-30 15:49 ` Dan Williams 2020-09-30 15:49 ` Dan Williams 2020-09-30 16:24 ` Borislav Petkov 2020-09-30 16:24 ` Borislav Petkov 2020-09-30 16:28 ` Linus Torvalds 2020-09-30 16:28 ` Linus Torvalds 2020-09-30 16:38 ` Borislav Petkov 2020-09-30 16:38 ` Borislav Petkov
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