Re: [PATCH] tpm: Add reserved memory event log

Eddie James
2023-01-17T15:09:49Z

On 1/16/23 00:53, Jarkko Sakkinen wrote:
> On Tue, Jan 03, 2023 at 10:20:10AM -0600, Eddie James wrote:
>> Some platforms may desire to pass the event log up to linux in the
>> 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@linux.ibm.com>
> Which platforms?
>
> I do not see information of
>
> + void (*release)(void *ptr);
>
> in the commit message. The description of the implemenation approach is
> missing.

Hi, please see v2 which is a two patch series. I have changed the
implementation to avoid this release pointer.
https://patchwork.kernel.org/project/linux-integrity/list/?series=711832

Thanks,

Eddie

>
>
>> ---
>> drivers/char/tpm/eventlog/of.c | 38 +++++++++++++++++++++++++++++++++-
>> drivers/char/tpm/tpm-chip.c | 3 ++-
>> include/linux/tpm.h | 1 +
>> 3 files changed, 40 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/char/tpm/eventlog/of.c b/drivers/char/tpm/eventlog/of.c
>> index a9ce66d09a75..0455d7f61c10 100644
>> --- a/drivers/char/tpm/eventlog/of.c
>> +++ b/drivers/char/tpm/eventlog/of.c
>> @@ -11,12 +11,48 @@
>> */
>>
>> #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 = memremap(res.start, resource_size(&res), MEMREMAP_WB);
>> + if (!chip->log.bios_event_log) {
>> + dev_info(&chip->dev, "err memremap\n");
>> + return -ENOMEM;
>> + }
>> +
>> + chip->log.release = memunmap;
>> + 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;
>> +}
> We do not want to support TPM 1.2 for new features.
>
>> +
>> int tpm_read_log_of(struct tpm_chip *chip)
>> {
>> struct device_node *np;
>> @@ -38,7 +74,7 @@ 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;
>>
>> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
>> index 741d8f3e8fb3..09ea8145d7c6 100644
>> --- a/drivers/char/tpm/tpm-chip.c
>> +++ b/drivers/char/tpm/tpm-chip.c
>> @@ -267,7 +267,7 @@ static void tpm_dev_release(struct device *dev)
>> idr_remove(&dev_nums_idr, chip->dev_num);
>> mutex_unlock(&idr_lock);
>>
>> - kfree(chip->log.bios_event_log);
>> + chip->log.release(chip->log.bios_event_log);
>> kfree(chip->work_space.context_buf);
>> kfree(chip->work_space.session_buf);
>> kfree(chip->allocated_banks);
>> @@ -324,6 +324,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
>> init_rwsem(&chip->ops_sem);
>>
>> chip->ops = ops;
>> + chip->log.release = (void(*)(void *))kfree;
> Why do you need this cast?
>
>>
>> mutex_lock(&idr_lock);
>> rc = idr_alloc(&dev_nums_idr, NULL, 0, TPM_NUM_DEVICES, GFP_KERNEL);
>> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
>> index dfeb25a0362d..f1c0b0eb20a5 100644
>> --- a/include/linux/tpm.h
>> +++ b/include/linux/tpm.h
>> @@ -109,6 +109,7 @@ struct tpm_space {
>> struct tpm_bios_log {
>> void *bios_event_log;
>> void *bios_event_log_end;
>> + void (*release)(void *ptr);
>> };
>>
>> struct tpm_chip_seqops {
>> --
>> 2.31.1
>>
> BR, Jarkko