[PATCH v2 1/1] efi_loader: installation of EFI_RNG_PROTOCOL

[Scott K Logan]

On Fri, 2020-09-25 at 20:36 +0200, Heinrich Schuchardt wrote:
> Having an EFI_RNG_PROTOCOL without a backing RNG device leads to failure
> to boot Linux 5.8.
> 
> Only install the EFI_RNG_PROTOCOL if we have a RNG device.
> 
> Reported-by: Scott K Logan <logans at cottsay.net>
> Cc: Neil Armstrong <narmstrong at baylibre.com>
> Cc: Ard Biesheuvel <ardb at kernel.org>
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> ---
> v2:
> 	add missing braces
> ---
>  include/efi_loader.h           |  3 ++-
>  lib/efi_loader/efi_rng.c       | 30 +++++++++++++++++++++++++++++-
>  lib/efi_loader/efi_root_node.c |  4 ----
>  lib/efi_loader/efi_setup.c     |  5 +++++
>  4 files changed, 36 insertions(+), 6 deletions(-)
> 
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index 0baa1d2324..7eea5566fd 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -154,7 +154,6 @@ extern const struct efi_hii_config_routing_protocol efi_hii_config_routing;
>  extern const struct efi_hii_config_access_protocol efi_hii_config_access;
>  extern const struct efi_hii_database_protocol efi_hii_database;
>  extern const struct efi_hii_string_protocol efi_hii_string;
> -extern const struct efi_rng_protocol efi_rng_protocol;
> 
>  uint16_t *efi_dp_str(struct efi_device_path *dp);
> 
> @@ -404,6 +403,8 @@ efi_status_t EFIAPI efi_convert_pointer(efi_uintn_t debug_disposition,
>  efi_status_t efi_console_register(void);
>  /* Called by bootefi to make all disk storage accessible as EFI objects */
>  efi_status_t efi_disk_register(void);
> +/* Called by efi_init_obj_list() to install EFI_RNG_PROTOCOL */
> +efi_status_t efi_rng_register(void);
>  /* Create handles and protocols for the partitions of a block device */
>  int efi_disk_create_partitions(efi_handle_t parent, struct blk_desc *desc,
>  			       const char *if_typename, int diskid,
> diff --git a/lib/efi_loader/efi_rng.c b/lib/efi_loader/efi_rng.c
> index caef4085b0..a8a87007b6 100644
> --- a/lib/efi_loader/efi_rng.c
> +++ b/lib/efi_loader/efi_rng.c
> @@ -3,6 +3,8 @@
>   * Copyright (c) 2019, Linaro Limited
>   */
> 
> +#define LOG_CATEGORY LOGC_EFI
> +
>  #include <common.h>
>  #include <dm.h>
>  #include <efi_loader.h>
> @@ -144,7 +146,33 @@ back:
>  	return EFI_EXIT(status);
>  }
> 
> -const struct efi_rng_protocol efi_rng_protocol = {
> +static const struct efi_rng_protocol efi_rng_protocol = {
>  	.get_info = rng_getinfo,
>  	.get_rng = getrng,
>  };
> +
> +/**
> + * efi_rng_register() - register EFI_RNG_PROTOCOL
> + *
> + * If a RNG device is available, the Random Number Generator Protocol is
> + * registered.
> + *
> + * Return:	An error status is only returned if adding the protocol fails.
> + */
> +efi_status_t efi_rng_register(void)
> +{
> +	efi_status_t ret;
> +	struct udevice *dev;
> +
> +	ret = platform_get_rng_device(&dev);
> +	if (ret != EFI_SUCCESS) {
> +		log_warning("Missing RNG device for EFI_RNG_PROTOCOL");
> +		return EFI_SUCCESS;
> +	}
> +	ret = efi_add_protocol(efi_root, &efi_guid_rng_protocol,
> +			       (void *)&efi_rng_protocol);
> +	if (ret != EFI_SUCCESS)
> +		log_err("Cannot install EFI_RNG_PROTOCOL");
> +
> +	return ret;
> +}
> diff --git a/lib/efi_loader/efi_root_node.c b/lib/efi_loader/efi_root_node.c
> index 76d18fb1a4..f68b0fdc61 100644
> --- a/lib/efi_loader/efi_root_node.c
> +++ b/lib/efi_loader/efi_root_node.c
> @@ -80,10 +80,6 @@ efi_status_t efi_root_node_register(void)
>  			 /* HII configuration routing protocol */
>  			 &efi_guid_hii_config_routing_protocol,
>  			 (void *)&efi_hii_config_routing,
> -#endif
> -#if CONFIG_IS_ENABLED(EFI_RNG_PROTOCOL)
> -			 &efi_guid_rng_protocol,
> -			 (void *)&efi_rng_protocol,
>  #endif
>  			 NULL));
>  	efi_root->type = EFI_OBJECT_TYPE_U_BOOT_FIRMWARE;
> diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
> index 6196c0a06c..45226c5c1a 100644
> --- a/lib/efi_loader/efi_setup.c
> +++ b/lib/efi_loader/efi_setup.c
> @@ -151,6 +151,11 @@ efi_status_t efi_init_obj_list(void)
>  	if (ret != EFI_SUCCESS)
>  		goto out;
>  #endif
> +	if (IS_ENABLED(CONFIG_EFI_RNG_PROTOCOL)) {
> +		ret = efi_rng_register();
> +		if (ret != EFI_SUCCESS)
> +			goto out;
> +	}
>  	/* Initialize variable services */
>  	ret = efi_init_variables();
>  	if (ret != EFI_SUCCESS)
> --
> 2.28.0
Tested-by: Scott K Logan <logans at cottsay.net>