[PATCH v2 0/2] perf: arm_pmuv3: Don't use PMCCNTR_EL0 on SMT cores

[Yicong Yang <yangyicong@huawei.com>]

From: Yicong Yang <yangyicong@hisilicon.com>

This patchset fixed CPU_CYCLES counting on SMT system. CPU_CYCLES can use
PMCCNTR_EL0 which will count the hardware processor clock rather than the
PE clock (ARM DDI0487 L.b D13.1.3) on SMT cores which fails the users
expectation as CPU_CYCLES (0x0011) is defined to count on each PE cycles.
Fix this by avoid using PMCCNTR_EL0 on SMT cores when counting CPU_CYCLES.

Changes since v1:
- remove redundant comment and add tags on Patch 1/2
- detect the SMT implementation during PMU probe rather than runtime
Link: https://lore.kernel.org/linux-arm-kernel/20250812080830.20796-1-yangyicong@huawei.com/

Yicong Yang (2):
  perf: arm_pmuv3: Factor out PMCCNTR_EL0 use conditions
  perf: arm_pmuv3: Don't use PMCCNTR_EL0 on SMT cores

 drivers/perf/arm_pmu.c        |  3 +++
 drivers/perf/arm_pmuv3.c      | 39 +++++++++++++++++++++++++++++++++--
 include/linux/arch_topology.h | 11 ++++++++++
 include/linux/perf/arm_pmu.h  |  1 +
 4 files changed, 52 insertions(+), 2 deletions(-)

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2.24.0