linux-kernel - Re: [PATCH v2 2/2] tpm: Add reserved memory event log

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Message-ID: <3161efa3-2e72-bcc4-95d9-736a55f6535e@linux.ibm.com>
Date:   Wed, 18 Jan 2023 08:49:30 -0600
From:   Eddie James <eajames@...ux.ibm.com>
To:     Stefan Berger <stefanb@...ux.ibm.com>,
        linux-integrity@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, jgg@...pe.ca, jarkko@...nel.org,
        peterhuewe@....de
Subject: Re: [PATCH v2 2/2] tpm: Add reserved memory event log


On 1/18/23 07:27, Stefan Berger wrote:
>
>
> On 1/13/23 11:10, Eddie James wrote:
>> Some platforms may desire to pass the event log up to linux in the
>
> Which platforms are these that work like this?


Platforms booting from U-Boot without EFI. So at the moment, IBM's 
OpenBMC systems hope to use this.

Thanks,

Eddie


>
>    Stefan
>
>> form of a reserved memory region. Add support for this in the TPM
>> core to find the reserved memory region and map it.
>>
>> Signed-off-by: Eddie James <eajames@...ux.ibm.com>
>> ---
>>   drivers/char/tpm/eventlog/of.c | 38 +++++++++++++++++++++++++++++++++-
>>   1 file changed, 37 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/char/tpm/eventlog/of.c 
>> b/drivers/char/tpm/eventlog/of.c
>> index 741ab2204b11..c815cadf00a4 100644
>> --- a/drivers/char/tpm/eventlog/of.c
>> +++ b/drivers/char/tpm/eventlog/of.c
>> @@ -12,12 +12,48 @@
>>     #include <linux/device.h>
>>   #include <linux/slab.h>
>> +#include <linux/io.h>
>> +#include <linux/ioport.h>
>>   #include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_reserved_mem.h>
>>   #include <linux/tpm_eventlog.h>
>>     #include "../tpm.h"
>>   #include "common.h"
>>   +static int tpm_read_log_memory_region(struct tpm_chip *chip)
>> +{
>> +    struct device_node *node;
>> +    struct resource res;
>> +    int rc;
>> +
>> +    node = of_parse_phandle(chip->dev.parent->of_node, 
>> "memory-region", 0);
>> +    if (!node) {
>> +        dev_info(&chip->dev, "no phandle\n");
>> +        return -ENODEV;
>> +    }
>> +
>> +    rc = of_address_to_resource(node, 0, &res);
>> +    of_node_put(node);
>> +    if (rc) {
>> +        dev_info(&chip->dev, "no mem\n");
>> +        return rc;
>> +    }
>> +
>> +    chip->log.bios_event_log = devm_memremap(&chip->dev, res.start, 
>> resource_size(&res),
>> +                         MEMREMAP_WB);
>> +    if (!chip->log.bios_event_log) {
>> +        dev_info(&chip->dev, "err memremap\n");
>> +        return -ENOMEM;
>> +    }
>> +
>> +    chip->log.bios_event_log_end = chip->log.bios_event_log + 
>> resource_size(&res);
>> +
>> +    return chip->flags & TPM_CHIP_FLAG_TPM2 ? 
>> EFI_TCG2_EVENT_LOG_FORMAT_TCG_2 :
>> +        EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
>> +}
>> +
>>   int tpm_read_log_of(struct tpm_chip *chip)
>>   {
>>       struct device_node *np;
>> @@ -39,7 +75,7 @@ int tpm_read_log_of(struct tpm_chip *chip)
>>       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;
>> +        return tpm_read_log_memory_region(chip);
>>       if (sizep == NULL || basep == NULL)
>>           return -EIO;