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    Subject[PATCH 5.19 0079/1157] RISC-V: Update user page mapping only once during start
    Date
    From: Atish Patra <atishp@rivosinc.com>

    commit 133a6d1fe7d7ad8393af025c4dde379c0616661f upstream.

    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: f5bfa23f576f ("RISC-V: Add a perf core library for pmu drivers")
    Reviewed-by: Anup Patel <anup@brainfault.org>
    Signed-off-by: Atish Patra <atishp@rivosinc.com>
    Reviewed-by: Guo Ren <guoren@kernel.org>
    Cc: stable@vger.kernel.org
    Link: https://lore.kernel.org/r/20220711174632.4186047-3-atishp@rivosinc.com
    Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/perf/riscv_pmu.c | 1 -
    drivers/perf/riscv_pmu_sbi.c | 1 +
    2 files changed, 1 insertion(+), 1 deletion(-)

    --- a/drivers/perf/riscv_pmu.c
    +++ b/drivers/perf/riscv_pmu.c
    @@ -170,7 +170,6 @@ int riscv_pmu_event_set_period(struct pe
    left = (max_period >> 1);

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

    return overflow;
    }
    --- a/drivers/perf/riscv_pmu_sbi.c
    +++ b/drivers/perf/riscv_pmu_sbi.c
    @@ -542,6 +542,7 @@ static inline void pmu_sbi_start_overflo
    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++;

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