[PATCH 5.18 0071/1095] RISC-V: Update user page mapping only once during start

Greg Kroah-Hartman
2022-08-15T20:15:29Z

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++;