[PATCH v6 3/3] tpm: get tpm event log from bloblist

[Simon Glass]

Hi Raymond,

On Fri, 17 Jan 2025 at 09:36, Raymond Mao <raymond.mao at linaro.org> wrote:
>
> Get tpm event log from bloblist instead of FDT when bloblist is
> enabled and valid from previous boot stage.
>
> Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
> ---
> Changes in v2
> - Remove patch dependency.
> - Remove the fallback to FDT when BLOBLIST is selected.
> Changes in v3
> - Malloc an 8KB buffer when user eventlog buffer does not exist.
> Changes in v4
> - Replace the default eventlog size with TPM2_EVENT_LOG_SIZE.
> Changes in v5
> - Replace TPM2_EVENT_LOG_SIZE with CONFIG_TPM2_EVENT_LOG_SIZE.
> - Add an inline TODO comment.
> Changes in v6
> - Remove the malloc and keep the buffer pointed by "sml" for the fallback
>   as it is the right place for linux to discover the eventlog.
>
>  lib/tpm_tcg2.c | 58 +++++++++++++++++++++++++++++++++-----------------
>  1 file changed, 38 insertions(+), 20 deletions(-)

Reviewed-by: Simon Glass <sjg at chromium.org>

with nit below

>
> diff --git a/lib/tpm_tcg2.c b/lib/tpm_tcg2.c
> index 4134d93a35..6425bf143a 100644
> --- a/lib/tpm_tcg2.c
> +++ b/lib/tpm_tcg2.c
> @@ -5,6 +5,7 @@
>
>  #include <dm.h>
>  #include <dm/of_access.h>
> +#include <malloc.h>
>  #include <tpm_api.h>
>  #include <tpm-common.h>
>  #include <tpm-v2.h>
> @@ -19,6 +20,7 @@
>  #include <linux/unaligned/generic.h>
>  #include <linux/unaligned/le_byteshift.h>
>  #include "tpm-utils.h"
> +#include <bloblist.h>
>
>  int tcg2_get_pcr_info(struct udevice *dev, u32 *supported_bank, u32 *active_bank,
>                       u32 *bank_num)
> @@ -672,21 +674,40 @@ void tcg2_measurement_term(struct udevice *dev, struct tcg2_event_log *elog,
>
>  __weak int tcg2_platform_get_log(struct udevice *dev, void **addr, u32 *size)
>  {
> -       const __be32 *addr_prop;
> -       const __be32 *size_prop;
> +       const __be32 *addr_prop = NULL;
> +       const __be32 *size_prop = NULL;
>         int asize;
>         int ssize;
> +       struct ofnode_phandle_args args;
> +       phys_addr_t a;
> +       fdt_size_t s;
>
>         *addr = NULL;
>         *size = 0;
>
> -       addr_prop = dev_read_prop(dev, "tpm_event_log_addr", &asize);
> -       if (!addr_prop)
> -               addr_prop = dev_read_prop(dev, "linux,sml-base", &asize);
> +       *addr = bloblist_get_blob(BLOBLISTT_TPM_EVLOG, size);
> +       if (*addr && *size)
> +               return 0;
>
> -       size_prop = dev_read_prop(dev, "tpm_event_log_size", &ssize);
> -       if (!size_prop)
> +       /*
> +        * TODO:
> +        * Replace BLOBLIST with a new kconfig for handoff all components
> +        * (fdt, tpm event log, etc...) from previous boot stage via bloblist
> +        * mandatorily following Firmware Handoff spec.

Just to mention, this patch is fine with me, but I don't agree with
having a new Kconfig for this. That would need a separate discussion.

> +        */
> +       if (!CONFIG_IS_ENABLED(BLOBLIST)) {
> +               addr_prop = dev_read_prop(dev, "tpm_event_log_addr", &asize);
> +               size_prop = dev_read_prop(dev, "tpm_event_log_size", &ssize);
> +       }
> +
> +       /*
> +        * If no eventlog was observed, a sml buffer is required for the kernel
> +        * to discover the eventlog.
> +        */
> +       if (!addr_prop || !size_prop) {
> +               addr_prop = dev_read_prop(dev, "linux,sml-base", &asize);
>                 size_prop = dev_read_prop(dev, "linux,sml-size", &ssize);
> +       }
>
>         if (addr_prop && size_prop) {
>                 u64 a = of_read_number(addr_prop, asize / sizeof(__be32));
> @@ -694,22 +715,19 @@ __weak int tcg2_platform_get_log(struct udevice *dev, void **addr, u32 *size)
>
>                 *addr = map_physmem(a, s, MAP_NOCACHE);
>                 *size = (u32)s;
> -       } else {
> -               struct ofnode_phandle_args args;
> -               phys_addr_t a;
> -               fdt_size_t s;
>
> -               if (dev_read_phandle_with_args(dev, "memory-region", NULL, 0,
> -                                              0, &args))
> -                       return -ENODEV;
> +               return 0;
> +       }
> +
> +       if (dev_read_phandle_with_args(dev, "memory-region", NULL, 0, 0, &args))
> +               return -ENODEV;
>
> -               a = ofnode_get_addr_size(args.node, "reg", &s);
> -               if (a == FDT_ADDR_T_NONE)
> -                       return -ENOMEM;
> +       a = ofnode_get_addr_size(args.node, "reg", &s);
> +       if (a == FDT_ADDR_T_NONE)
> +               return -ENOMEM;
>
> -               *addr = map_physmem(a, s, MAP_NOCACHE);
> -               *size = (u32)s;
> -       }
> +       *addr = map_physmem(a, s, MAP_NOCACHE);
> +       *size = (u32)s;
>
>         return 0;
>  }
> --
> 2.25.1
>

Regards,
Simon