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[PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf

Started byHoan Tran <hotran@apm.com>
First post2016-09-15 01:10 +0200
Last post2016-09-19 21:00 +0200
Articles 4 — 3 participants

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  [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf Hoan Tran <hotran@apm.com> - 2016-09-15 01:10 +0200
    Re: [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-09-15 02:50 +0200
      Re: [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf Hoan Tran <hotran@apm.com> - 2016-09-15 05:10 +0200
        Re: [PATCH] cpufreq: CPPC: Avoid overflow when calculating  desired_perf Al Stone <ahs3@redhat.com> - 2016-09-19 21:00 +0200

#1483754 — [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf

FromHoan Tran <hotran@apm.com>
Date2016-09-15 01:10 +0200
Subject[PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf
Message-ID<shrtw-7hp-27@gated-at.bofh.it>
This patch fixes overflow issue when calculating the desired_perf.

Signed-off-by: Hoan Tran <hotran@apm.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

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#1483793

From"Rafael J. Wysocki" <rjw@rjwysocki.net>
Date2016-09-15 02:50 +0200
Message-ID<sht2h-8g5-1@gated-at.bofh.it>
In reply to#1483754
On Wednesday, September 14, 2016 04:08:28 PM Hoan Tran wrote:
> This patch fixes overflow issue when calculating the desired_perf.
> 
> Signed-off-by: Hoan Tran <hotran@apm.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;

That's on top of the CPPC material in linux-next I gather?

Which commit does it fix?

Thanks,
Rafael

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#1483833

FromHoan Tran <hotran@apm.com>
Date2016-09-15 05:10 +0200
Message-ID<shvdL-1or-1@gated-at.bofh.it>
In reply to#1483793
Hi Rafael,

On Wed, Sep 14, 2016 at 5:50 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
> On Wednesday, September 14, 2016 04:08:28 PM Hoan Tran wrote:
>> This patch fixes overflow issue when calculating the desired_perf.
>>
>> Signed-off-by: Hoan Tran <hotran@apm.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;
>
> That's on top of the CPPC material in linux-next I gather?

Yes, it's on TOP of linux-next.

>
> Which commit does it fix?

This is a fix for ad38677df44b67e0f5b6c4d31e9c2734abde8ed9 (cpufreq:
CPPC: Force reporting values in KHz to fix user space interface)
http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/cpufreq/cppc_cpufreq.c?id=ad38677df44b67e0f5b6c4d31e9c2734abde8ed9

Thanks
Hoan

>
> Thanks,
> Rafael
>

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#1486764 — Re: [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf

FromAl Stone <ahs3@redhat.com>
Date2016-09-19 21:00 +0200
SubjectRe: [PATCH] cpufreq: CPPC: Avoid overflow when calculating desired_perf
Message-ID<sjbXj-EM-3@gated-at.bofh.it>
In reply to#1483833
On 09/14/2016 09:06 PM, Hoan Tran wrote:
> Hi Rafael,
> 
> On Wed, Sep 14, 2016 at 5:50 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>> On Wednesday, September 14, 2016 04:08:28 PM Hoan Tran wrote:
>>> This patch fixes overflow issue when calculating the desired_perf.
>>>
>>> Signed-off-by: Hoan Tran <hotran@apm.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;
>>
>> That's on top of the CPPC material in linux-next I gather?
> 
> Yes, it's on TOP of linux-next.
> 
>>
>> Which commit does it fix?
> 
> This is a fix for ad38677df44b67e0f5b6c4d31e9c2734abde8ed9 (cpufreq:
> CPPC: Force reporting values in KHz to fix user space interface)
> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/drivers/cpufreq/cppc_cpufreq.c?id=ad38677df44b67e0f5b6c4d31e9c2734abde8ed9
> 
> Thanks
> Hoan
> 
>>
>> Thanks,
>> Rafael
>>

Nice catch, Hoan.  Thanks!

-- 
ciao,
al
-----------------------------------
Al Stone
Software Engineer
Red Hat, Inc.
ahs3@redhat.com
-----------------------------------

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