linux-kernel - [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired

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Message-Id: <1473894508-22270-1-git-send-email-hotran@apm.com>
Date:   Wed, 14 Sep 2016 16:08:28 -0700
From:   Hoan Tran <hotran@....com>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        pprakash@...eaurora.org, Al Stone <ahs3@...hat.com>
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        lho@....com, Duc Dang <dhdang@....com>, Hoan Tran <hotran@....com>
Subject: [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf

This patch fixes overflow issue when calculating the desired_perf.

Signed-off-by: Hoan Tran <hotran@....com>
---
 drivers/cpufreq/cppc_cpufreq.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 894e465..3e0961e 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -84,7 +84,8 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
 
 	cpu = all_cpu_data[policy->cpu];
 
-	cpu->perf_ctrls.desired_perf = target_freq * policy->max / cppc_dmi_max_khz;
+	cpu->perf_ctrls.desired_perf =
+		(u64)target_freq * policy->max / cppc_dmi_max_khz;
 	freqs.old = policy->cur;
 	freqs.new = target_freq;
 
-- 
1.9.1