linux-kernel - [PATCH 0/9] tools: Make {clear,set}

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20221119013450.2643007-1-seanjc@google.com>
Date:   Sat, 19 Nov 2022 01:34:41 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Yury Norov <yury.norov@...il.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Marc Zyngier <maz@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        James Morse <james.morse@....com>,
        Alexandru Elisei <alexandru.elisei@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev,
        kvmarm@...ts.cs.columbia.edu, kvm@...r.kernel.org,
        Sean Christopherson <seanjc@...gle.com>
Subject: [PATCH 0/9] tools: Make {clear,set}_bit() atomic for reals

For obvious reasons I'd like to route the this through Paolo's tree.
In theory, taking just patch 5 through tip would work, but creating a
topic branch seems like the way to go, though maybe I'm being overly
paranoid.  The current tip/perf/core doesn't have any conflicts, nor does
it have new set_bit() or clear_bit() users.

 
Code sitting in kvm/queue for 6.2 adds functionality that relies on
clear_bit() being an atomic operation.  Unfortunately, despite being
implemented in atomic.h (among other strong hits that they should be
atomic), clear_bit() and set_bit() aren't actually atomic (and of course
I realized this _just_ after everything got queued up).

Move current tools/ users of clear_bit() and set_bit() to the
double-underscore versions (which tools/ already provides and documents
as being non-atomic), and then implement clear_bit() and set_bit() as
actual atomics to fix the KVM selftests bug.

Perf and KVM are the only affected users.  NVDIMM also has test code
in tools/, but that builds against the kernel proper.  The KVM code is
well tested and fully audited.  The perf code is lightly tested; if I
understand the build system, it's probably not even fully compile tested.

Patches 1 and 2 are completely unrelated and are fixes for patches
sitting in kvm/queue.  Paolo, they can be squashed if you want to rewrite
history.

Patch 3 fixes a hilarious collision in a KVM ARM selftest that will arise
when clear_bit() is converted to an atomic.

Patch 4 changes clear_bit() and set_bit() to take an "unsigned long"
instead of an "int" so that patches 5-6 aren't accompanied by functional
changes.  I.e. if something in perf is somehow relying on "bit" being a
signed int, failures will bisect to patch 4 and not to the
supposed-to-be-a-nop conversion to __clear_bit() and __set_bit().

Patch 5-9 switch perf+KVM and complete the conversion.

Applies on:
  
  git://git.kernel.org/pub/scm/virt/kvm/kvm.git queue

Sean Christopherson (9):
  KVM: selftests: Add rdmsr_from_l2() implementation in Hyper-V eVMCS
    test
  KVM: selftests: Remove unused "vcpu" param to fix build error
  KVM: arm64: selftests: Enable single-step without a "full" ucall()
  tools: Take @bit as an "unsigned long" in {clear,set}_bit() helpers
  perf tools: Use dedicated non-atomic clear/set bit helpers
  KVM: selftests: Use non-atomic clear/set bit helpers in KVM tests
  tools: Drop conflicting non-atomic test_and_{clear,set}_bit() helpers
  tools: Drop "atomic_" prefix from atomic test_and_set_bit()
  tools: KVM: selftests: Convert clear/set_bit() to actual atomics

 tools/arch/x86/include/asm/atomic.h           |  6 +++-
 tools/include/asm-generic/atomic-gcc.h        | 13 ++++++-
 tools/include/asm-generic/bitops/atomic.h     | 15 ++++----
 tools/include/linux/bitmap.h                  | 34 -------------------
 tools/perf/bench/find-bit-bench.c             |  2 +-
 tools/perf/builtin-c2c.c                      |  6 ++--
 tools/perf/builtin-kwork.c                    |  6 ++--
 tools/perf/builtin-record.c                   |  6 ++--
 tools/perf/builtin-sched.c                    |  2 +-
 tools/perf/tests/bitmap.c                     |  2 +-
 tools/perf/tests/mem2node.c                   |  2 +-
 tools/perf/util/affinity.c                    |  4 +--
 tools/perf/util/header.c                      |  8 ++---
 tools/perf/util/mmap.c                        |  6 ++--
 tools/perf/util/pmu.c                         |  2 +-
 .../util/scripting-engines/trace-event-perl.c |  2 +-
 .../scripting-engines/trace-event-python.c    |  2 +-
 tools/perf/util/session.c                     |  2 +-
 tools/perf/util/svghelper.c                   |  2 +-
 .../selftests/kvm/aarch64/arch_timer.c        |  2 +-
 .../selftests/kvm/aarch64/debug-exceptions.c  | 21 ++++++------
 tools/testing/selftests/kvm/dirty_log_test.c  | 34 +++++++++----------
 .../selftests/kvm/include/ucall_common.h      |  8 +++++
 .../testing/selftests/kvm/lib/ucall_common.c  |  2 +-
 .../selftests/kvm/x86_64/hyperv_evmcs.c       | 13 +++++--
 .../selftests/kvm/x86_64/hyperv_svm_test.c    |  4 +--
 .../selftests/kvm/x86_64/hyperv_tlb_flush.c   |  2 +-
 27 files changed, 102 insertions(+), 106 deletions(-)


base-commit: 3321eef4acb51c303f0598d8a8493ca58528a054
-- 
2.38.1.584.g0f3c55d4c2-goog