[PATCH 6.6 063/396] cpufreq: Limit resolving a frequency to policy min/max

Greg Kroah-Hartman
2024-04-01T16:39:41Z

From: Shivnandan Kumar <quic_kshivnan@quicinc.com>

[ Upstream commit d394abcb12bb1a6f309c1221fdb8e73594ecf1b4 ]

Resolving a frequency to an efficient one should not transgress
policy->max (which can be set for thermal reason) and policy->min.

Currently, there is possibility where scaling_cur_freq can exceed
scaling_max_freq when scaling_max_freq is an inefficient frequency.

Add a check to ensure that resolving a frequency will respect
policy->min/max.

Cc: All applicable <stable@vger.kernel.org>
Fixes: 1f39fa0dccff ("cpufreq: Introducing CPUFREQ_RELATION_E")
Signed-off-by: Shivnandan Kumar <quic_kshivnan@quicinc.com>
[ rjw: Whitespace adjustment, changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/cpufreq.h | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 71d186d6933a5..3a4cefb25ba61 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -1021,6 +1021,18 @@ static inline int cpufreq_table_find_index_c(struct cpufreq_policy *policy,
efficiencies);
}

+static inline bool cpufreq_is_in_limits(struct cpufreq_policy *policy, int idx)
+{
+ unsigned int freq;
+
+ if (idx < 0)
+ return false;
+
+ freq = policy->freq_table[idx].frequency;
+
+ return freq == clamp_val(freq, policy->min, policy->max);
+}
+
static inline int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
@@ -1054,7 +1066,8 @@ static inline int cpufreq_frequency_table_target(struct cpufreq_policy *policy,
return 0;
}

- if (idx < 0 && efficiencies) {
+ /* Limit frequency index to honor policy->min/max */
+ if (!cpufreq_is_in_limits(policy, idx) && efficiencies) {
efficiencies = false;
goto retry;
}
--
2.43.0