Re: [PATCH v2 2/2] efi_loader: Reset system after CapsuleUpdate on disk

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Wed, Feb 02, 2022 at 10:54:43PM +0900, Masami Hiramatsu wrote:
> Add a config option to reset system soon after processing capsule update
> on disk.

We no longer have a new config option :)

> This is required in UEFI specification 2.9 Section 8.5.5
>  "Delivery of Capsules via file on Mass Storage device" as;
> 
>     In all cases that a capsule is identified for processing the system is
>     restarted after capsule processing is completed.
> 
> This also reports the result of each capsule update so that the user can
> notice that the capsule update has been succeeded or not from console log.
> 
> Signed-off-by: Masami Hiramatsu <masami.hiramatsu@linaro.org>
> ---
>  Changes in v3:
>   - Log succeeded capsule update in info level.
>   - Use sysreset if possible.
>   - Use do_reset() and hang() instead of panic().
>  Changes in v2:
>   - Remove kconfig option to disable this feature.
>   - Use panic() instead of do_reset() so that if the reset fails,
>     the machine halt.
>   - Log the result of each capsule update always.
> ---
>  lib/efi_loader/efi_capsule.c |   22 ++++++++++++++++++++--
>  1 file changed, 20 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
> index 1ec7ea29ff..ade9155042 100644
> --- a/lib/efi_loader/efi_capsule.c
> +++ b/lib/efi_loader/efi_capsule.c
> @@ -14,9 +14,11 @@
>  #include <env.h>
>  #include <fdtdec.h>
>  #include <fs.h>
> +#include <hang.h>
>  #include <malloc.h>
>  #include <mapmem.h>
>  #include <sort.h>
> +#include <sysreset.h>
>  #include <asm/global_data.h>
>  
>  #include <crypto/pkcs7.h>
> @@ -1120,8 +1122,11 @@ efi_status_t efi_launch_capsules(void)
>  		if (ret == EFI_SUCCESS) {
>  			ret = efi_capsule_update_firmware(capsule);
>  			if (ret != EFI_SUCCESS)
> -				log_err("Applying capsule %ls failed\n",
> +				log_err("Applying capsule %ls failed.\n",
>  					files[i]);
> +			else
> +				log_info("Applying capsule %ls succeeded.\n",
> +					 files[i]);
>  
>  			/* create CapsuleXXXX */
>  			set_capsule_result(index, capsule, ret);
> @@ -1142,6 +1147,19 @@ efi_status_t efi_launch_capsules(void)
>  		free(files[i]);
>  	free(files);
>  
> -	return ret;
> +	/*
> +	 * UEFI spec requires to reset system after complete processing capsule
> +	 * update on the storage.
> +	 */
> +	puts("Reboot after firmware update");
> +	if (CONFIG_IS_ENABLED(SYSRESET)) {
> +		reset_cpu();
> +	} else {
> +		do_reset(NULL, 0, 0, NULL);
> +		hang();
> +	}
> +	/* not reach here */

Despite the code that I proposed, I have a few concerns:
1) warm or cold reset
Now that we are updating firmware, we may have to initiate
a cold reset in some cases.
(That's why I used 'sysreset(WARM)' to raise a question.)

From the viewpoint of UEFI specification,
  * A type of reset can be determined per capsule by calling
    QueryCapsuleCapabilities API.
    (The spec said, "Returns if the capsule can be supported via
     UpdateCapsule()" and Capsule-on-disk might be out of scope?)
  * There exists ResetSystem API and it takes a *reset type*
    as a parameter.

2) ResetSystem at boot time
So we may want to internally make use of efi_reset_system() following
capsule-on-disk processing.
The current implementation, however, does not utilize SYSRESET drivers,
but call do_reset(). This should be changed (as I suggested above?).

-Takahiro Akashi


> +
> +	return 0;
>  }
>  #endif /* CONFIG_EFI_CAPSULE_ON_DISK */
>