Unverified Commit 133a6d1f authored by Atish Patra's avatar Atish Patra Committed by Palmer Dabbelt
Browse files

RISC-V: Update user page mapping only once during start 



Currently, riscv_pmu_event_set_period updates the userpage mapping.
However, the caller of riscv_pmu_event_set_period should update
the userpage mapping because the counter can not be updated/started
from set_period function in counter overflow path.

Invoke the perf_event_update_userpage at the caller so that it
doesn't get invoked twice during counter start path.

Fixes: f5bfa23f ("RISC-V: Add a perf core library for pmu drivers")
Reviewed-by: default avatarAnup Patel <anup@brainfault.org>
Signed-off-by: default avatarAtish Patra <atishp@rivosinc.com>
Reviewed-by: default avatarGuo Ren <guoren@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220711174632.4186047-3-atishp@rivosinc.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent acc1b919

drivers/perf/riscv_pmu.c

+0 −1
Original line number Diff line number Diff line
@@ -170,7 +170,6 @@ int riscv_pmu_event_set_period(struct perf_event *event) 
		left = (max_period >> 1);



	local64_set(&hwc->prev_count, (u64)-left);

	perf_event_update_userpage(event);



	return overflow;

}

drivers/perf/riscv_pmu_sbi.c

+1 −0
Original line number Diff line number Diff line
@@ -532,6 +532,7 @@ static inline void pmu_sbi_start_overflow_mask(struct riscv_pmu *pmu, 
			sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, idx, 1,

				  flag, init_val, 0, 0);

#endif

			perf_event_update_userpage(event);

		}

		ctr_ovf_mask = ctr_ovf_mask >> 1;

		idx++;