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

[Eddie James]

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@xxxxxxxxxxxxx>
> > ---
> >   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;