This is resurrecting Raphael's series[1] to enable userspace counter access on arm64. My previous version is here[2].
New in this version is adding userspace read support into libperf rather than adding yet another copy of the read loop. Details are in patch 5. The following changes to the arm64 support have been made compared to Raphael's last version: The major change is support for heterogeneous systems with some restrictions. Specifically, userspace must pin itself to like CPUs, open a specific PMU by type, and use h/w specific events. The tests have been reworked to demonstrate this. Chained events are not supported. The problem with supporting chained events was there's no way to distinguish between a chained event and a native 64-bit counter. We could add some flag, but do self monitoring processes really need that? Native 64-bit counters are supported if the PMU h/w has support. As there's already an explicit ABI to request 64-bit counters, userspace can request 64-bit counters and if user access is not enabled, then it must retry with 32-bit counters. Prior versions broke the build on arm32 (surprisingly never caught by 0-day). As a result, event_mapped and event_unmapped implementations have been moved into the arm64 code. There was a bug in that pmc_width was not set in the user page. The tests now check for this. The documentation has been converted to rST. I've added sections on chained events and heterogeneous. The tests have been expanded to test the cycle counter access. Rob [1] https://lore.kernel.org/linux-arm-kernel/20190822144220.27860-1-raphael.ga...@arm.com/ [2] https://lore.kernel.org/linux-arm-kernel/20200707205333.624938-1-r...@kernel.org/ Raphael Gault (4): arm64: pmu: Add hook to handle pmu-related undefined instructions arm64: pmu: Add function implementation to update event index in userpage arm64: perf: Enable pmu counter direct access for perf event on armv8 Documentation: arm64: Document PMU counters access from userspace Rob Herring (5): tools/include: Add an initial math64.h libperf: Add support for user space counter access libperf: Add arm64 support to perf_mmap__read_self() perf: arm64: Add test for userspace counter access on heterogeneous systems perf: Remove x86 specific rdpmc test Documentation/arm64/index.rst | 1 + .../arm64/perf_counter_user_access.rst | 56 ++++++ arch/arm64/include/asm/mmu.h | 5 + arch/arm64/include/asm/mmu_context.h | 2 + arch/arm64/include/asm/perf_event.h | 14 ++ arch/arm64/kernel/cpufeature.c | 4 +- arch/arm64/kernel/perf_event.c | 116 +++++++++++ include/linux/perf/arm_pmu.h | 2 + tools/include/linux/math64.h | 75 +++++++ tools/lib/perf/Documentation/libperf.txt | 1 + tools/lib/perf/evsel.c | 33 +++ tools/lib/perf/include/internal/evsel.h | 2 + tools/lib/perf/include/internal/mmap.h | 3 + tools/lib/perf/include/perf/evsel.h | 1 + tools/lib/perf/libperf.map | 1 + tools/lib/perf/mmap.c | 188 ++++++++++++++++++ tools/lib/perf/tests/test-evsel.c | 64 ++++++ tools/perf/arch/arm64/include/arch-tests.h | 7 + tools/perf/arch/arm64/tests/Build | 1 + tools/perf/arch/arm64/tests/arch-tests.c | 4 + tools/perf/arch/arm64/tests/user-events.c | 170 ++++++++++++++++ tools/perf/arch/x86/include/arch-tests.h | 1 - tools/perf/arch/x86/tests/Build | 1 - tools/perf/arch/x86/tests/arch-tests.c | 4 - tools/perf/arch/x86/tests/rdpmc.c | 182 ----------------- 25 files changed, 748 insertions(+), 190 deletions(-) create mode 100644 Documentation/arm64/perf_counter_user_access.rst create mode 100644 tools/include/linux/math64.h create mode 100644 tools/perf/arch/arm64/tests/user-events.c delete mode 100644 tools/perf/arch/x86/tests/rdpmc.c -- 2.25.1