From: Palmer Dabbelt <palmer@xxxxxxxxxxxx> commit 5a5294fbe0200d1327f0e089135dad77b45aa2ee upstream. These counters were part of the ISA when we froze the uABI, removing them breaks userspace. Link: https://lore.kernel.org/all/YxEhC%2FmDW1lFt36J@xxxxxxxxxxx/ Fixes: e9991434596f ("RISC-V: Add perf platform driver based on SBI PMU extension") Tested-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> Reviewed-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220928131807.30386-1-palmer@xxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/perf/riscv_pmu_sbi.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/perf/riscv_pmu_sbi.c +++ b/drivers/perf/riscv_pmu_sbi.c @@ -639,8 +639,11 @@ static int pmu_sbi_starting_cpu(unsigned struct riscv_pmu *pmu = hlist_entry_safe(node, struct riscv_pmu, node); struct cpu_hw_events *cpu_hw_evt = this_cpu_ptr(pmu->hw_events); - /* Enable the access for TIME csr only from the user mode now */ - csr_write(CSR_SCOUNTEREN, 0x2); + /* + * Enable the access for CYCLE, TIME, and INSTRET CSRs from userspace, + * as is necessary to maintain uABI compatibility. + */ + csr_write(CSR_SCOUNTEREN, 0x7); /* Stop all the counters so that they can be enabled from perf */ pmu_sbi_stop_all(pmu);
