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Message-Id: <1439351359-29532-1-git-send-email-yu.c.chen@intel.com> Date: Wed, 12 Aug 2015 11:49:19 +0800 From: Chen Yu <yu.c.chen@...el.com> To: kristen@...ux.intel.com, rjw@...ysocki.net, viresh.kumar@...aro.org Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, rui.zhang@...el.com, lenb@...nel.org, Chen Yu <yu.c.chen@...el.com> Subject: [PATCH][rfc] intel_pstate: Fix user input of min/max to legal policy region In current code, if system is using performance policy, user can modify the max_perf_pct to any values lower than 100: $ grep . /sys/devices/system/cpu/intel_pstate/m*_perf_pct /sys/devices/system/cpu/intel_pstate/max_perf_pct:100 /sys/devices/system/cpu/intel_pstate/min_perf_pct:100 $ echo 80 > /sys/devices/system/cpu/intel_pstate/max_perf_pct $ grep . /sys/devices/system/cpu/intel_pstate/m*_perf_pct /sys/devices/system/cpu/intel_pstate/max_perf_pct:80 /sys/devices/system/cpu/intel_pstate/min_perf_pct:100 the max_perf_pct above is lower than min_perf_pct, which is not reasonable. This patch solves this problem by clamping min_perf_pct and max_perf_pct to be strictly inside [min_policy_pct,max_policy_pct]. Signed-off-by: Chen Yu <yu.c.chen@...el.com> --- drivers/cpufreq/intel_pstate.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index fcb929e..3702c5a 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -423,6 +423,7 @@ static ssize_t store_max_perf_pct(struct kobject *a, struct attribute *b, limits.max_sysfs_pct = clamp_t(int, input, 0 , 100); limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct); + limits.max_perf_pct = max(limits.min_policy_pct, limits.max_perf_pct); limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100)); if (hwp_active) @@ -442,6 +443,7 @@ static ssize_t store_min_perf_pct(struct kobject *a, struct attribute *b, limits.min_sysfs_pct = clamp_t(int, input, 0 , 100); limits.min_perf_pct = max(limits.min_policy_pct, limits.min_sysfs_pct); + limits.min_perf_pct = min(limits.max_policy_pct, limits.min_perf_pct); limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); if (hwp_active) @@ -985,12 +987,14 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy) limits.min_policy_pct = (policy->min * 100) / policy->cpuinfo.max_freq; limits.min_policy_pct = clamp_t(int, limits.min_policy_pct, 0 , 100); - limits.min_perf_pct = max(limits.min_policy_pct, limits.min_sysfs_pct); - limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); - limits.max_policy_pct = (policy->max * 100) / policy->cpuinfo.max_freq; limits.max_policy_pct = clamp_t(int, limits.max_policy_pct, 0 , 100); + + limits.min_perf_pct = max(limits.min_policy_pct, limits.min_sysfs_pct); + limits.min_perf_pct = min(limits.max_policy_pct, limits.min_perf_pct); + limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct); + limits.max_perf_pct = max(limits.min_policy_pct, limits.max_perf_pct); limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100)); if (hwp_active) -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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