Reading the content of delivered_reg and reference_reg should be in
the same critical section, in case any interrupt comes, which could
lead to inaccurate frequency calculation.
Signed-off-by: Zeng Heng <zengheng4@xxxxxxxxxx>
---
drivers/acpi/cppc_acpi.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c
index c51d3ccb4cca..176f3e2e67f8 100644
--- a/drivers/acpi/cppc_acpi.c
+++ b/drivers/acpi/cppc_acpi.c
@@ -1315,6 +1315,7 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
struct cppc_pcc_data *pcc_ss_data = NULL;
u64 delivered, reference, ref_perf, ctr_wrap_time;
int ret = 0, regs_in_pcc = 0;
+ unsigned long flags;
if (!cpc_desc) {
pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
@@ -1350,8 +1351,11 @@ int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
}
}
+ local_irq_save(flags);
cpc_read(cpunum, delivered_reg, &delivered);
cpc_read(cpunum, reference_reg, &reference);
+ local_irq_restore(flags);
+
cpc_read(cpunum, ref_perf_reg, &ref_perf);
/*
--
2.25.1
