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authorPalmer Dabbelt <palmer@rivosinc.com>2022-09-28 16:18:07 +0300
committerPalmer Dabbelt <palmer@rivosinc.com>2022-10-13 21:18:39 +0300
commit5a5294fbe0200d1327f0e089135dad77b45aa2ee (patch)
tree538d6e3f66215967336ee80b5088d3799fd938e7
parenta8616d2dc193b6becc36b5f3cfeaa9ac7a5762f9 (diff)
downloadlinux-5a5294fbe0200d1327f0e089135dad77b45aa2ee.tar.xz
RISC-V: Re-enable counter access from userspace
These counters were part of the ISA when we froze the uABI, removing them breaks userspace. Link: https://lore.kernel.org/all/YxEhC%2FmDW1lFt36J@aurel32.net/ Fixes: e9991434596f ("RISC-V: Add perf platform driver based on SBI PMU extension") Tested-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Conor Dooley <conor.dooley@microchip.com> Link: https://lore.kernel.org/r/20220928131807.30386-1-palmer@rivosinc.com Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
-rw-r--r--drivers/perf/riscv_pmu_sbi.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
index 15e5a47be7d5..3852c18362f5 100644
--- a/drivers/perf/riscv_pmu_sbi.c
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -652,8 +652,11 @@ static int pmu_sbi_starting_cpu(unsigned int cpu, struct hlist_node *node)
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);