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

[Eddie James]

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@xxxxxxxxxxxxx>
> 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