linux-kernel - Re: [PATCH v5 4/6] tpm: of: Make of-tree specific function commonly available

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Message-ID: <3a9196b3-c510-0c32-8b70-572d9c4fe69d@linux.ibm.com>
Date:   Fri, 15 Jul 2022 12:01:36 -0400
From:   Stefan Berger <stefanb@...ux.ibm.com>
To:     Jarkko Sakkinen <jarkko@...nel.org>
Cc:     kexec@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org, nayna@...ux.ibm.com,
        nasastry@...ibm.com, mpe@...erman.id.au,
        Jason Gunthorpe <jgg@...pe.ca>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>
Subject: Re: [PATCH v5 4/6] tpm: of: Make of-tree specific function commonly
 available


On 7/10/22 23:04, Jarkko Sakkinen wrote:
> On Wed, Jul 06, 2022 at 11:23:27AM -0400, Stefan Berger wrote:
>> Simplify tpm_read_log_of() by moving reusable parts of the code into
>> an inline function that makes it commonly available so it can be
>> used also for kexec support. Call the new of_tpm_get_sml_parameters()
>> function from the TPM Open Firmware driver.
>>
>> Signed-off-by: Stefan Berger <stefanb@...ux.ibm.com>
>> Cc: Jarkko Sakkinen <jarkko@...nel.org>
>> Cc: Jason Gunthorpe <jgg@...pe.ca>
>> Cc: Rob Herring <robh+dt@...nel.org>
>> Cc: Frank Rowand <frowand.list@...il.com>
>>
>> ---
>> v4:
>>   - converted to inline function
>> ---
>>   drivers/char/tpm/eventlog/of.c | 31 +++++--------------------------
>>   include/linux/tpm.h            | 27 +++++++++++++++++++++++++++
>>   2 files changed, 32 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
>> index a9ce66d09a75..f9462d19632e 100644
>> --- a/drivers/char/tpm/eventlog/of.c
>> +++ b/drivers/char/tpm/eventlog/of.c
>> @@ -12,6 +12,7 @@
>>   
>>   #include <linux/slab.h>
>>   #include <linux/of.h>
>> +#include <linux/tpm.h>
>>   #include <linux/tpm_eventlog.h>
>>   
>>   #include "../tpm.h"
>> @@ -20,11 +21,10 @@
>>   int tpm_read_log_of(struct tpm_chip *chip)
>>   {
>>   	struct device_node *np;
>> -	const u32 *sizep;
>> -	const u64 *basep;
>>   	struct tpm_bios_log *log;
>>   	u32 size;
>>   	u64 base;
>> +	int ret;
>>   
>>   	log = &chip->log;
>>   	if (chip->dev.parent && chip->dev.parent->of_node)
>> @@ -35,30 +35,9 @@ int tpm_read_log_of(struct tpm_chip *chip)
>>   	if (of_property_read_bool(np, "powered-while-suspended"))
>>   		chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
>>   
>> -	sizep = of_get_property(np, "linux,sml-size", NULL);
>> -	basep = of_get_property(np, "linux,sml-base", NULL);
>> -	if (sizep == NULL && basep == NULL)
>> -		return -ENODEV;
>> -	if (sizep == NULL || basep == NULL)
>> -		return -EIO;
>> -
>> -	/*
>> -	 * For both vtpm/tpm, firmware has log addr and log size in big
>> -	 * endian format. But in case of vtpm, there is a method called
>> -	 * sml-handover which is run during kernel init even before
>> -	 * device tree is setup. This sml-handover function takes care
>> -	 * of endianness and writes to sml-base and sml-size in little
>> -	 * endian format. For this reason, vtpm doesn't need conversion
>> -	 * but physical tpm needs the conversion.
>> -	 */


Jarkko,

  can I apply your R-b tag after putting this lost comment back into the 
inline function?
    Stefan

>> -	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
>> -	    of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
>> -		size = be32_to_cpup((__force __be32 *)sizep);
>> -		base = be64_to_cpup((__force __be64 *)basep);
>> -	} else {
>> -		size = *sizep;
>> -		base = *basep;
>> -	}
>> +	ret = of_tpm_get_sml_parameters(np, &base, &size);
>> +	if (ret < 0)
>> +		return ret;
>>   
>>   	if (size == 0) {
>>   		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
>> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
>> index dfeb25a0362d..b3dff255bc58 100644
>> --- a/include/linux/tpm.h
>> +++ b/include/linux/tpm.h
>> @@ -460,4 +460,31 @@ static inline struct tpm_chip *tpm_default_chip(void)
>>   	return NULL;
>>   }
>>   #endif
>> +
>> +#ifdef CONFIG_OF
>> +static inline int of_tpm_get_sml_parameters(struct device_node *np,
>> +					    u64 *base, u32 *size)
>> +{
>> +	const u32 *sizep;
>> +	const u64 *basep;
>> +
>> +	sizep = of_get_property(np, "linux,sml-size", NULL);
>> +	basep = of_get_property(np, "linux,sml-base", NULL);
>> +	if (sizep == NULL && basep == NULL)
>> +		return -ENODEV;
>> +	if (sizep == NULL || basep == NULL)
>> +		return -EIO;
>> +
>> +	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0 &&
>> +	    of_property_match_string(np, "compatible", "IBM,vtpm20") < 0) {
>> +		*size = be32_to_cpup((__force __be32 *)sizep);
>> +		*base = be64_to_cpup((__force __be64 *)basep);
>> +	} else {
>> +		*size = *sizep;
>> +		*base = *basep;
>> +	}
>> +	return 0;
>> +}
>> +#endif
>> +
>>   #endif
>> -- 
>> 2.35.1
>>
> 
> 
> Reviewed-by: Jarkko Sakkinen <jarkko@...nel.org>
> 
> BR, Jarkko
> 
> _______________________________________________
> kexec mailing list
> kexec@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

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