[PATCH] ACPI: RISC-V: Fix false warning in cppc_read_ffh() for same-CPU reads

[wang.yechao255]

From: Wang Yechao <wang.yechao255@xxxxxxxxxx>

Commit 997c021abc6e ("cpufreq: CPPC: Update FIE arch_freq_scale in
ticks for non-PCC regs") changed the CPPC Frequency Invariance Engine
to read AMU counters directly from the scheduler tick for non-PCC
register spaces (like FFH), instead of deferring to a kthread. This
means cppc_read_ffh() is now called with IRQs disabled from the tick
handler, triggering the warning.

This is the same fix as commit df6e4ab654dc ("arm64: topology: Fix
false warning in counters_read_on_cpu() for same-CPU reads").

Fixes: 997c021abc6e ("cpufreq: CPPC: Update FIE arch_freq_scale in ticks for non-PCC regs")
Signed-off-by: Wang Yechao <wang.yechao255@xxxxxxxxxx>
---
 drivers/acpi/riscv/cppc.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/riscv/cppc.c b/drivers/acpi/riscv/cppc.c
index 42c1a9052470..5dce0377a8df 100644
--- a/drivers/acpi/riscv/cppc.c
+++ b/drivers/acpi/riscv/cppc.c
@@ -98,16 +98,19 @@ int cpc_read_ffh(int cpu, struct cpc_reg *reg, u64 *val)
 {
 	struct sbi_cppc_data data;

-	if (WARN_ON_ONCE(irqs_disabled()))
-		return -EPERM;
-
 	if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_SBI) {
 		if (!cppc_ext_present)
 			return -EINVAL;

 		data.reg = FFH_CPPC_SBI_REG(reg->address);

-		smp_call_function_single(cpu, sbi_cppc_read, &data, 1);
+		if (irqs_disabled()) {
+			if (WARN_ON_ONCE(cpu != smp_processor_id()))
+				return -EPERM;
+			sbi_cppc_read(&data);
+		} else {
+			smp_call_function_single(cpu, sbi_cppc_read, &data, 1);
+		}

 		*val = data.ret.value;

@@ -115,7 +118,13 @@ int cpc_read_ffh(int cpu, struct cpc_reg *reg, u64 *val)
 	} else if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_CSR) {
 		data.reg = FFH_CPPC_CSR_NUM(reg->address);

-		smp_call_function_single(cpu, cppc_ffh_csr_read, &data, 1);
+		if (irqs_disabled()) {
+			if (WARN_ON_ONCE(cpu != smp_processor_id()))
+				return -EPERM;
+			cppc_ffh_csr_read(&data);
+		} else {
+			smp_call_function_single(cpu, cppc_ffh_csr_read, &data, 1);
+		}

 		*val = data.ret.value;

-- 
2.43.5