[PATCH 1/1] efi_loader: find distro device-path for media devices

[E Shattow]

On Sat, Jul 13, 2024 at 4:30 AM Heinrich Schuchardt
<heinrich.schuchardt at canonical.com> wrote:
>
> The auto-generated load options for media device do not contain a partition
> node. We cannot expect the simple file protocol here.
>
> Get the partition device-path via the loaded image protocol.
>
> Fixes: e91b68fd6b83 ("efi_loader: load distro dtb in bootmgr")
> Reported-by: E Shattow <lucent at gmail.com>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
> ---
>  include/efi_loader.h         |  2 +-
>  lib/efi_loader/efi_bootmgr.c |  2 +-
>  lib/efi_loader/efi_fdt.c     | 33 +++++++++++++++++++--------------
>  3 files changed, 21 insertions(+), 16 deletions(-)
>
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index 6c993e1a694..2a06fbe4704 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -1205,6 +1205,6 @@ efi_status_t efi_load_option_dp_join(struct efi_device_path **dp,
>
>  int efi_get_distro_fdt_name(char *fname, int size, int seq);
>
> -void efi_load_distro_fdt(void **fdt, efi_uintn_t *fdt_size);
> +void efi_load_distro_fdt(efi_handle_t handle, void **fdt, efi_uintn_t *fdt_size);
>
>  #endif /* _EFI_LOADER_H */
> diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
> index 304ed43595c..589d3996b68 100644
> --- a/lib/efi_loader/efi_bootmgr.c
> +++ b/lib/efi_loader/efi_bootmgr.c
> @@ -1277,7 +1277,7 @@ efi_status_t efi_bootmgr_run(void *fdt)
>                 if (fdt_lo)
>                         fdt = fdt_lo;
>                 if (!fdt) {
> -                       efi_load_distro_fdt(&fdt_distro, &fdt_size);
> +                       efi_load_distro_fdt(handle, &fdt_distro, &fdt_size);
>                         fdt = fdt_distro;
>                 }
>         }
> diff --git a/lib/efi_loader/efi_fdt.c b/lib/efi_loader/efi_fdt.c
> index 86ba00c2bdd..4ccf2055be3 100644
> --- a/lib/efi_loader/efi_fdt.c
> +++ b/lib/efi_loader/efi_fdt.c
> @@ -75,28 +75,34 @@ int efi_get_distro_fdt_name(char *fname, int size, int seq)
>  /**
>   * efi_load_distro_fdt() - load distro device-tree
>   *
> + * @handle:    handle of loaded image
>   * @fdt:       on return device-tree, must be freed via efi_free_pages()
>   * @fdt_size:  buffer size
>   */
> -void efi_load_distro_fdt(void **fdt, efi_uintn_t *fdt_size)
> +void efi_load_distro_fdt(efi_handle_t handle, void **fdt, efi_uintn_t *fdt_size)
>  {
> -       struct efi_device_path *rem, *dp;
> +       struct efi_device_path *dp;
>         efi_status_t  ret;
> +       struct efi_handler *handler;
> +       struct efi_loaded_image *loaded_image;
>         efi_handle_t device;
>
>         *fdt = NULL;
>
> -       dp = efi_get_dp_from_boot(NULL);
> -       if (!dp)
> +       /* Get boot device from loaded image protocol */
> +       ret = efi_search_protocol(handle, &efi_guid_loaded_image, &handler);
> +       if (ret != EFI_SUCCESS)
>                 return;
> -       device = efi_dp_find_obj(dp, NULL, &rem);
> -       ret = efi_search_protocol(device, &efi_simple_file_system_protocol_guid,
> -                                 NULL);
> +       loaded_image = handler->protocol_interface;
> +       device = loaded_image->device_handle;
> +
> +       /* Get device path of boot device */
> +       ret = efi_search_protocol(device, &efi_guid_device_path, &handler);
>         if (ret != EFI_SUCCESS)
> -               goto err;
> -       memcpy(rem, &END, sizeof(END));
> +               return;
> +       dp = handler->protocol_interface;
>
> -       /* try the various available names */
> +       /* Try the various available names */
>         for (int seq = 0; ; ++seq) {
>                 struct efi_device_path *file;
>                 char buf[255];
> @@ -108,10 +114,9 @@ void efi_load_distro_fdt(void **fdt, efi_uintn_t *fdt_size)
>                         break;
>                 ret = efi_load_image_from_path(true, file, fdt, fdt_size);
>                 efi_free_pool(file);
> -               if (ret == EFI_SUCCESS)
> +               if (ret == EFI_SUCCESS) {
> +                       log_debug("Fdt %pD loaded\n", file);
>                         break;
> +               }
>         }
> -
> -err:
> -       efi_free_pool(dp);
>  }
> --
> 2.45.2
>

Tested-by: E Shattow <lucent at gmail.com>