* [PATCH] arm64: topology: fix arch_cpu_idle_enter()
@ 2026-08-07 13:52 seanwang1
0 siblings, 0 replies; only message in thread
From: seanwang1 @ 2026-08-07 13:52 UTC (permalink / raw)
To: Catalin Marinas, Will Deacon
Cc: linux-arm-kernel, linux-kernel, Beata Michalska, Lifeng Zheng,
Greg Kroah-Hartman, Geert Uytterhoeven, Sumit Gupta, Yunhui Cui,
seanwang1, Xuewen Yan
arch_cpu_idle_enter() directly calls amu_scale_freq_tick() to update
arch_freq_scale when CPU enters idle state. This bypasses the sft_data
pointer check that topology_clear_scale_freq_source() relies on.
As a result, even after calling topology_clear_scale_freq_source() with
SCALE_FREQ_SOURCE_ARCH to disable AMU-based frequency scaling, the
arch_freq_scale value can still be modified by AMU counters when the
CPU goes idle through the arch_cpu_idle_enter() path.
Fix by replacing the direct amu_scale_freq_tick() call with
topology_scale_freq_tick(), which is the generic interface for updating
frequency scale and properly respects the sft_data pointer state.
Co-developed-by: Xuewen Yan <xuewen.yan@unisoc.com>
Signed-off-by: Sean Wang <seanwang1@lenovo.com>
Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
---
arch/arm64/kernel/topology.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index b32f13358fbb..f617ef5c9903 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -176,7 +176,7 @@ void arch_cpu_idle_enter(void)
/* Kick in AMU update but only if one has not happened already */
if (housekeeping_cpu(cpu, HK_TYPE_TICK) &&
time_is_before_jiffies(per_cpu(cpu_amu_samples.last_scale_update, cpu)))
- amu_scale_freq_tick();
+ topology_scale_freq_tick();
}
#define AMU_SAMPLE_EXP_MS 20
--
2.25.1
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