linux-kernel - Re: [PATCH] powercap, intel

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Date:	Wed, 09 Dec 2015 08:27:05 -0500
From:	Prarit Bhargava <prarit@...hat.com>
To:	Seiichi Ikarashi <s.ikarashi@...fujitsu.com>,
	linux-kernel@...r.kernel.org
CC:	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Jacob Pan <jacob.jun.pan@...ux.intel.com>,
	Radivoje Jovanovic <radivoje.jovanovic@...el.com>,
	Mathias Krause <minipli@...glemail.com>,
	Ajay Thomas <ajay.thomas.david.rajamanickam@...el.com>
Subject: Re: [PATCH] powercap, intel_rapl.c, fix BIOS lock check



On 12/08/2015 07:12 PM, Seiichi Ikarashi wrote:
> On 2015-12-09 03:33, Prarit Bhargava wrote:
>> Intel RAPL initialized on several systems where the BIOS lock bit (msr
>> 0x610, bit 63) was set.  This occured because the return value of
>> rapl_read_data_raw() was being checked, rather than the value of the variable
>> passed in, locked.
>>
>> This patch properly implments the rapl_read_data_raw() call to check the
>> variable locked, and now the Intel RAPL driver outputs the warning:
>>
>> 	intel_rapl: RAPL package 0 domain package locked by BIOS
>>
>> and does not initialize for the package.
>>
>> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
>> Cc: Jacob Pan <jacob.jun.pan@...ux.intel.com>
>> Cc: Radivoje Jovanovic <radivoje.jovanovic@...el.com>
>> Cc: Seiichi Ikarashi <s.ikarashi@...fujitsu.com>
>> Cc: Mathias Krause <minipli@...glemail.com>
>> Cc: Ajay Thomas <ajay.thomas.david.rajamanickam@...el.com>
>> Signed-off-by: Prarit Bhargava <prarit@...hat.com>
>> ---
>>  drivers/powercap/intel_rapl.c |    6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/powercap/intel_rapl.c b/drivers/powercap/intel_rapl.c
>> index cc97f08..0b0d09d 100644
>> --- a/drivers/powercap/intel_rapl.c
>> +++ b/drivers/powercap/intel_rapl.c
>> @@ -1341,11 +1341,13 @@ static int rapl_detect_domains(struct rapl_package *rp, int cpu)
>>  
>>  	for (rd = rp->domains; rd < rp->domains + rp->nr_domains; rd++) {
>>  		/* check if the domain is locked by BIOS */
>> -		if (rapl_read_data_raw(rd, FW_LOCK, false, &locked)) {
>> +		ret = rapl_read_data_raw(rd, FW_LOCK, false, &locked);
>> +		if (ret)
>> +			return ret;
>> +		if (locked)
>>  			pr_info("RAPL package %d domain %s locked by BIOS\n",
>>  				rp->id, rd->name);
>>  				rd->state |= DOMAIN_STATE_BIOS_LOCKED;
>> -		}
>>  	}
> 
> A good spot!
> But this patch looks setting DOMAIN_STATE_BIOS_LOCKED bit to all package domains.
> I suppose what you are going to do is like below.
> 
> --- a/drivers/powercap/intel_rapl.c	2015-11-02 09:05:25.000000000 +0900
> +++ b/drivers/powercap/intel_rapl.c	2015-12-09 09:05:33.386142840 +0900
> @@ -1340,10 +1340,13 @@ static int rapl_detect_domains(struct ra
>  
>  	for (rd = rp->domains; rd < rp->domains + rp->nr_domains; rd++) {
>  		/* check if the domain is locked by BIOS */
> -		if (rapl_read_data_raw(rd, FW_LOCK, false, &locked)) {
> +		ret = rapl_read_data_raw(rd, FW_LOCK, false, &locked);
> +		if (ret)
> +			return ret;
> +		if (locked) {
>  			pr_info("RAPL package %d domain %s locked by BIOS\n",
>  				rp->id, rd->name);
> -				rd->state |= DOMAIN_STATE_BIOS_LOCKED;
> +			rd->state |= DOMAIN_STATE_BIOS_LOCKED;
>  		}
>  	}

Oh geez :)  Of course ... I'll resubmit shortly.

P.

>  
> 
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