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Message-Id: <20221208084402.863310-1-anshuman.khandual@arm.com>
Date: Thu, 8 Dec 2022 14:13:55 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
mark.rutland@....com
Cc: Anshuman Khandual <anshuman.khandual@....com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>, Mark Brown <broonie@...nel.org>,
James Clark <james.clark@....com>,
Rob Herring <robh@...nel.org>, Marc Zyngier <maz@...nel.org>,
Suzuki Poulose <suzuki.poulose@....com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
linux-perf-users@...r.kernel.org
Subject: [PATCH V6 0/7] arm64/perf: Enable branch stack sampling
This series enables perf branch stack sampling support on arm64 platform
via a new arch feature called Branch Record Buffer Extension (BRBE). All
relevant register definitions could be accessed here.
https://developer.arm.com/documentation/ddi0601/2021-12/AArch64-Registers
This series applies on v6.1-rc8.
Changes in V6:
- Restore the exception level privilege after reading the branch records
- Unpause the buffer after reading the branch records
- Decouple BRBCR_EL1_EXCEPTION/ERTN from perf event privilege level
- Reworked BRBE implementation and branch stack sampling support on arm pmu
- BRBE implementation is now part of overall ARMV8 PMU implementation
- BRBE implementation moved from drivers/perf/ to inside arch/arm64/kernel/
- CONFIG_ARM_BRBE_PMU renamed as CONFIG_ARM64_BRBE in arch/arm64/Kconfig
- File moved - drivers/perf/arm_pmu_brbe.c -> arch/arm64/kernel/brbe.c
- File moved - drivers/perf/arm_pmu_brbe.h -> arch/arm64/kernel/brbe.h
- BRBE name has been dropped from struct arm_pmu and struct hw_pmu_events
- BRBE name has been abstracted out as 'branches' in arm_pmu and hw_pmu_events
- BRBE name has been abstracted out as 'branches' in ARMV8 PMU implementation
- Added sched_task() callback into struct arm_pmu
- Added 'hw_attr' into struct arm_pmu encapsulating possible PMU HW attributes
- Dropped explicit attributes brbe_(v1p1, nr, cc, format) from struct arm_pmu
- Dropped brbfcr, brbcr, registers scratch area from struct hw_pmu_events
- Dropped brbe_users, brbe_context tracking in struct hw_pmu_events
- Added 'features' tracking into struct arm_pmu with ARM_PMU_BRANCH_STACK flag
- armpmu->hw_attr maps into 'struct brbe_hw_attr' inside BRBE implementation
- Set ARM_PMU_BRANCH_STACK in 'arm_pmu->features' after successful BRBE probe
- Added armv8pmu_branch_reset() inside armv8pmu_branch_enable()
- Dropped brbe_supported() as events will be rejected via ARM_PMU_BRANCH_STACK
- Dropped set_brbe_disabled() as well
- Reformated armv8pmu_branch_valid() warnings while rejecting unsupported events
Changes in V5:
https://lore.kernel.org/linux-arm-kernel/20221107062514.2851047-1-anshuman.khandual@arm.com/
- Changed BRBCR_EL1.VIRTUAL from 0b1 to 0b01
- Changed BRBFCR_EL1.EnL into BRBFCR_EL1.EnI
- Changed config ARM_BRBE_PMU from 'tristate' to 'bool'
Changes in V4:
https://lore.kernel.org/all/20221017055713.451092-1-anshuman.khandual@arm.com/
- Changed ../tools/sysreg declarations as suggested
- Set PERF_SAMPLE_BRANCH_STACK in data.sample_flags
- Dropped perfmon_capable() check in armpmu_event_init()
- s/pr_warn_once/pr_info in armpmu_event_init()
- Added brbe_format element into struct pmu_hw_events
- Changed v1p1 as brbe_v1p1 in struct pmu_hw_events
- Dropped pr_info() from arm64_pmu_brbe_probe(), solved LOCKDEP warning
Changes in V3:
https://lore.kernel.org/all/20220929075857.158358-1-anshuman.khandual@arm.com/
- Moved brbe_stack from the stack and now dynamically allocated
- Return PERF_BR_PRIV_UNKNOWN instead of -1 in brbe_fetch_perf_priv()
- Moved BRBIDR0, BRBCR, BRBFCR registers and fields into tools/sysreg
- Created dummy BRBINF_EL1 field definitions in tools/sysreg
- Dropped ARMPMU_EVT_PRIV framework which cached perfmon_capable()
- Both exception and exception return branche records are now captured
only if the event has PERF_SAMPLE_BRANCH_KERNEL which would already
been checked in generic perf via perf_allow_kernel()
Changes in V2:
https://lore.kernel.org/all/20220908051046.465307-1-anshuman.khandual@arm.com/
- Dropped branch sample filter helpers consolidation patch from this series
- Added new hw_perf_event.flags element ARMPMU_EVT_PRIV to cache perfmon_capable()
- Use cached perfmon_capable() while configuring BRBE branch record filters
Changes in V1:
https://lore.kernel.org/linux-arm-kernel/20220613100119.684673-1-anshuman.khandual@arm.com/
- Added CONFIG_PERF_EVENTS wrapper for all branch sample filter helpers
- Process new perf branch types via PERF_BR_EXTEND_ABI
Changes in RFC V2:
https://lore.kernel.org/linux-arm-kernel/20220412115455.293119-1-anshuman.khandual@arm.com/
- Added branch_sample_priv() while consolidating other branch sample filter helpers
- Changed all SYS_BRBXXXN_EL1 register definition encodings per Marc
- Changed the BRBE driver as per proposed BRBE related perf ABI changes (V5)
- Added documentation for struct arm_pmu changes, updated commit message
- Updated commit message for BRBE detection infrastructure patch
- PERF_SAMPLE_BRANCH_KERNEL gets checked during arm event init (outside the driver)
- Branch privilege state capture mechanism has now moved inside the driver
Changes in RFC V1:
https://lore.kernel.org/all/1642998653-21377-1-git-send-email-anshuman.khandual@arm.com/
Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Mark Brown <broonie@...nel.org>
Cc: James Clark <james.clark@....com>
Cc: Rob Herring <robh@...nel.org>
Cc: Marc Zyngier <maz@...nel.org>
Cc: Suzuki Poulose <suzuki.poulose@....com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-perf-users@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Anshuman Khandual (7):
drivers: perf: arm_pmu: Add new sched_task() callback
arm64/perf: Add BRBE registers and fields
arm64/perf: Add branch stack support in struct arm_pmu
arm64/perf: Add branch stack support in struct pmu_hw_events
arm64/perf: Add branch stack support in ARMV8 PMU
arm64/perf: Enable branch stack events via FEAT_BRBE
drivers: perf: arm_pmu: Enable branch stack sampling event
arch/arm64/Kconfig | 11 +
arch/arm64/include/asm/perf_event.h | 19 ++
arch/arm64/include/asm/sysreg.h | 103 +++++++
arch/arm64/kernel/Makefile | 1 +
arch/arm64/kernel/brbe.c | 454 ++++++++++++++++++++++++++++
arch/arm64/kernel/brbe.h | 266 ++++++++++++++++
arch/arm64/kernel/perf_event.c | 31 ++
arch/arm64/tools/sysreg | 161 ++++++++++
drivers/perf/arm_pmu.c | 12 +-
include/linux/perf/arm_pmu.h | 19 ++
10 files changed, 1075 insertions(+), 2 deletions(-)
create mode 100644 arch/arm64/kernel/brbe.c
create mode 100644 arch/arm64/kernel/brbe.h
--
2.25.1
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