[PATCH] efi_loader: Disable devices before handing over control

[Heinrich Schuchardt]

On 10/21/20 9:32 AM, Ilias Apalodimas wrote:
> U-Boot Driver Model is supposed to remove devices with either
> DM_REMOVE_ACTIVE_DMA or DM_REMOVE_OS_PREPARE flags set, before exiting.
> Our bootm command does that by explicitly calling calling
> "dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL);" and we also disable any
> USB devices.
>
> The EFI equivalent is doing none of those at the moment. As a result
> probing an fTPM driver now renders it unusable in Linux. During our
> (*probe) callback we open a session with OP-TEE, which is supposed to
> close with our (*remove) callback. Since the (*remove) is never called,
> once we boot into Linux and try to probe the device again we are getting
> a busy error response. We also never free
>
> So let's fix this by mimicking what bootm does and disconnect devices
> when efi_exit_boot_services() is called. Note that for the OP-TEE case
> and in particular any subsequent bootloader that wants to use a device
> (e.g GRUB) will need to call exit_boot_services() in order to close the
> session.

Hello Ilias,

thanks for the patch. Adding the function calls looks correct to me, but
sandbox_spl_defconfig gives me a compile time error with this patch, cf.
https://gitlab.denx.de/u-boot/custodians/u-boot-efi/-/jobs/166842

You might want to use Travis CI before resubmitting.

Best regards

Heinrich


>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> ---
>  lib/efi_loader/efi_boottime.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> index bf78176217c6..25e6cf0fe719 100644
> --- a/lib/efi_loader/efi_boottime.c
> +++ b/lib/efi_loader/efi_boottime.c
> @@ -18,6 +18,8 @@
>  #include <pe.h>
>  #include <u-boot/crc.h>
>  #include <watchdog.h>
> +#include <dm/device.h>
> +#include <dm/root.h>
>
>  DECLARE_GLOBAL_DATA_PTR;
>
> @@ -1994,7 +1996,10 @@ static efi_status_t EFIAPI efi_exit_boot_services(efi_handle_t image_handle,
>  			list_del(&evt->link);
>  	}
>
> +	if IS_ENABLED(CONFIG_USB_DEVICE)
> +		udc_disconnect();
>  	board_quiesce_devices();
> +	dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL);
>
>  	/* Patch out unsupported runtime function */
>  	efi_runtime_detach();
>