[PATCH v10 3/4] Boot var automatic management for removable medias

[Heinrich Schuchardt]

On 6/19/23 23:23, Raymond Mao wrote:
> Changes for complying to EFI spec §3.5.1.1
> 'Removable Media Boot Behavior'.
> Boot variables can be automatically generated during a removable
> media is probed. At the same time, unused boot variables will be
> detected and removed.
>
> Please note that currently the function 'efi_disk_remove' has no
> ability to distinguish below two scenarios
> a) Unplugging of a removable media under U-Boot
> b) U-Boot exiting and booting an OS
> Thus currently the boot variables management is not added into
> 'efi_disk_remove' to avoid boot options being added/erased
> repeatedly under scenario b) during power cycles
> See TODO comments under function 'efi_disk_remove' for more details
>
> Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
> ---
> Changes in v3
> - Split the patch into moving and renaming functions and
>    individual patches for each changed functionality
> Changes in v5
> - Move function call of efi_bootmgr_update_media_device_boot_option()
>    from efi_init_variables() to efi_init_obj_list()
> Changes in v6
> - Revert unrelated changes
> Changes in v7
> - adapt the return code of function
>    efi_bootmgr_update_media_device_boot_option()
> Changes in v8
> - add a note in the commit message for future reference
> Changes in v9
> - amend the note text in the commit message
> - add a TODO comment in 'efi_disk_remove'
> Changes in v10
> - fix typo and build failures with 'CONFIG_CMD_BOOTEFI_BOOTMGR=n'
>
>   lib/efi_loader/efi_disk.c  | 18 ++++++++++++++++++
>   lib/efi_loader/efi_setup.c |  7 +++++++
>   2 files changed, 25 insertions(+)
>
> diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
> index d2256713a8..911a4adfb1 100644
> --- a/lib/efi_loader/efi_disk.c
> +++ b/lib/efi_loader/efi_disk.c
> @@ -687,6 +687,13 @@ int efi_disk_probe(void *ctx, struct event *event)
>   			return -1;
>   	}
>
> +	/* only do the boot option management when UEFI sub-system is initialized */
> +	if (IS_ENABLED(CONFIG_CMD_BOOTEFI_BOOTMGR) && efi_obj_list_initialized == EFI_SUCCESS) {
> +		ret = efi_bootmgr_update_media_device_boot_option();
> +		if (ret != EFI_SUCCESS)
> +			return -1;
> +	}
> +
>   	return 0;
>   }
>
> @@ -773,6 +780,17 @@ int efi_disk_remove(void *ctx, struct event *event)
>   		return efi_disk_delete_part(dev);
>   	else
>   		return 0;
> +
> +	/*
> +	 * TODO A flag to distinguish below 2 different scenarios of this
> +	 * function call is needed:
> +	 * a) Unplugging of a removable media under U-Boot
> +	 * b) U-Boot exiting and booting an OS
> +	 * In case of scenario a), efi_bootmgr_update_media_device_boot_option()
> +	 * needs to be invoked here to update the boot options and remove the
> +	 * unnecessary ones.
> +	 */

As in future we want to integrate more EFI drivers with the driver model
such a status should be in a global variable. It will have to be set in
ExitBootServices() before invoking dm_remove_devices_flags().

Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>

> +
>   }
>
>   /**
> diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
> index 58d4e13402..69c8b27730 100644
> --- a/lib/efi_loader/efi_setup.c
> +++ b/lib/efi_loader/efi_setup.c
> @@ -245,6 +245,13 @@ efi_status_t efi_init_obj_list(void)
>   	if (ret != EFI_SUCCESS)
>   		goto out;
>
> +	if (IS_ENABLED(CONFIG_CMD_BOOTEFI_BOOTMGR)) {
> +		/* update boot option after variable service initialized */
> +		ret = efi_bootmgr_update_media_device_boot_option();
> +		if (ret != EFI_SUCCESS)
> +			goto out;
> +	}
> +
>   	/* Define supported languages */
>   	ret = efi_init_platform_lang();
>   	if (ret != EFI_SUCCESS)