[PATCH v2 0/2] perf: RISC-V: fix SBI PMU masks for RV32

[Xixin Liu]

Hi,

Thanks for the review, Paul.

v2 for 1/2: add Fixes and Assisted-by. Overflow masks are u64. On RV32
an unsigned-long bit at index 32 is 0, and BIT_ULL at index 32 is
0x100000000.

v2 for 2/2: same as v1, but do not pass only the first bitmap word into
CFG_MATCH. Walk each word like the stop-all path, with the counter base
set to i times BITS_PER_LONG. Share one helper for the 32-bit argument
split. Also add Fixes and Assisted-by.

Tested on qemu-system-riscv32 with CONFIG_ARCH_RV32I=y: 34 counters,
second word 0x7, CFG_MATCH retried at base 32 when the first word fails.
qemu-system-riscv64 still uses one word. A legacy-only RV32 kernel sets
cycle and instret bits and opens a cycles event. Overflow IRQ was not
taken on this QEMU virt guest, because sscof was not available to Linux.

Thanks,
Xixin Liu

---

Xixin Liu (2):
  perf: RISC-V: use BIT_ULL for u64 overflow masks
  perf: RISC-V: store available counter mask as bitmap

 drivers/perf/riscv_pmu_legacy.c |  5 ++-
 drivers/perf/riscv_pmu_sbi.c    | 88 ++++++++++++++++++++++++++++------------
 include/linux/perf/riscv_pmu.h  |  2 +-
 3 files changed, 66 insertions(+), 29 deletions(-)

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2.43.0