Re: [PATCH v3 2/2] tpm: Add reserved memory event log

Jarkko Sakkinen
2023-01-26T21:43:03Z

On Thu, Jan 26, 2023 at 03:08:10PM -0600, Eddie James wrote:
> Some platforms may desire to pass the event log up to Linux in the
> form of a reserved memory region. In particular, this is desirable
> for embedded systems or baseboard management controllers (BMCs)
> booting with U-Boot. IBM OpenBMC BMCs will be the first user.
> Add support for the reserved memory in the TPM core to find the
> region and map it.
>
> Signed-off-by: Eddie James <eajames@linux.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;
>
> --
> 2.31.1
>

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko