Re: [PATCH 09/11] efi: payload: bootm: add support for fit image

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

On 10/6/25 6:15 AM, chalianis1@gmail.com wrote:
> From: Ahmad Fatoum <a.fatoum@barebox.org>
> 
> Extend the EFI payload boot flow to support loading kernel, initrd,
> and devicetree directly from a FIT image. When a FIT is present,
> the loader extracts the relevant subimages ("kernel", "ramdisk",
> and "fdt") also support falling back to external files when possible.
> 
> Signed-off-by: Chali Anis <chalianis1@gmail.com>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> ---
>  efi/payload/Kconfig |   1 +
>  efi/payload/bootm.c | 125 ++++++++++++++++++++++++++++++++++++--------
>  2 files changed, 104 insertions(+), 22 deletions(-)
> 
> diff --git a/efi/payload/Kconfig b/efi/payload/Kconfig
> index e3a6a72d6a1c..4fb866210a69 100644
> --- a/efi/payload/Kconfig
> +++ b/efi/payload/Kconfig
> @@ -32,6 +32,7 @@ config EFI_HANDOVER_PROTOCOL
>  
>  config EFI_PAYLOAD_BOOTM
>  	bool "EFI bootm protocol"
> +	select BOOTM_FITIMAGE
>  	default !X86
>  
>  endif
> diff --git a/efi/payload/bootm.c b/efi/payload/bootm.c
> index d0e995be5d7c..3e9ccd42bf7f 100644
> --- a/efi/payload/bootm.c
> +++ b/efi/payload/bootm.c
> @@ -34,11 +34,74 @@
>  #include "image.h"
>  #include "setup_header.h"
>  
> +static bool ramdisk_is_fit(struct image_data *data)
> +{
> +	struct stat st;
> +
> +	if (bootm_signed_images_are_forced())
> +		return true;
> +
> +	if (data->initrd_file) {
> +		if (!stat(data->initrd_file, &st) && st.st_size > 0)
> +			return false;
> +	}
> +
> +	return data->os_fit ? fit_has_image(data->os_fit,
> +			data->fit_config, "ramdisk") > 0 : false;
> +}
> +
> +static bool fdt_is_fit(struct image_data *data)
> +{
> +	struct stat st;
> +
> +	if (bootm_signed_images_are_forced())
> +		return true;
> +
> +	if (data->oftree_file) {
> +		if (!stat(data->oftree_file, &st) && st.st_size > 0)
> +			return false;
> +	}
> +
> +	return data->os_fit ? fit_has_image(data->os_fit,
> +			data->fit_config, "fdt") > 0 : false;
> +}
> +
>  static int efi_load_os(struct image_data *data,
>  		       struct efi_loaded_image **loaded_image,
>  		       efi_handle_t *handle)
>  {
> -	return efi_load_image(data->os_file, loaded_image, handle);
> +	efi_status_t efiret;
> +	efi_handle_t h;
> +
> +	if (!data->os_fit)
> +		return efi_load_image(data->os_file, loaded_image, handle);
> +
> +	if (!data->fit_kernel)
> +		return -ENOENT;
> +
> +	efiret = BS->load_image(false, efi_parent_image, efi_device_path,
> +				(void *)data->fit_kernel, data->fit_kernel_size, &h);
> +	if (EFI_ERROR(efiret)) {
> +		pr_err("failed to LoadImage: %s\n", efi_strerror(efiret));
> +		goto out_mem;
> +	};
> +
> +	efiret = BS->open_protocol(h, &efi_loaded_image_protocol_guid,
> +				   (void **)loaded_image, efi_parent_image,
> +				   NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
> +	if (EFI_ERROR(efiret)) {
> +		pr_err("failed to OpenProtocol: %s\n", efi_strerror(efiret));
> +		goto out_unload;
> +	}
> +
> +	*handle = h;
> +
> +	return 0;
> +
> +out_unload:
> +	BS->unload_image(h);
> +out_mem:
> +	return -efi_errno(efiret);
>  }
>  
>  static int efi_load_ramdisk(struct image_data *data, void **initrd)
> @@ -47,17 +110,26 @@ static int efi_load_ramdisk(struct image_data *data, void **initrd)
>  	void *initrd_mem;
>  	int ret;
>  
> -	if (!data->initrd_file)
> -		return 0;
> -
> -	pr_info("Loading ramdisk from '%s'\n", data->initrd_file);
> -
> -	initrd_mem = read_file(data->initrd_file, &initrd_size);
> -	if (!initrd_mem) {
> -		ret = -errno;
> -		pr_err("Failed to read initrd from file '%s': %m\n",
> -		       data->initrd_file);
> -		return ret;
> +	if (ramdisk_is_fit(data)) {
> +		ret = fit_open_image(data->os_fit, data->fit_config, "ramdisk",
> +				     (const void **)&initrd_mem, &initrd_size);
> +		if (ret) {
> +			pr_err("Cannot open ramdisk image in FIT image: %m\n");
> +			return ret;
> +		}
> +	} else {
> +		if (!data->initrd_file)
> +			return 0;
> +
> +		pr_info("Loading ramdisk from '%s'\n", data->initrd_file);
> +
> +		initrd_mem = read_file(data->initrd_file, &initrd_size);
> +		if (!initrd_mem) {
> +			ret = -errno;
> +			pr_err("Failed to read initrd from file '%s': %m\n",
> +			       data->initrd_file);
> +			return ret;
> +		}
>  	}
>  
>  	ret = efi_initrd_register(initrd_mem, initrd_size);
> @@ -84,16 +156,25 @@ static int efi_load_fdt(struct image_data *data, void **fdt)
>  	unsigned long of_size;
>  	int ret;
>  
> -	if (!data->oftree_file)
> -		return 0;
> -
> -	pr_info("Loading devicetree from '%s'\n", data->oftree_file);
> -
> -	of_tree = read_file(data->oftree_file, &of_size);
> -	if (!of_tree) {
> -		ret = -errno;
> -		pr_err("Failed to read oftree: %m\n");
> -		return ret;
> +	if (fdt_is_fit(data)) {
> +		ret = fit_open_image(data->os_fit, data->fit_config, "fdt",
> +				     (const void **)&of_tree, &of_size);
> +		if (ret) {
> +			pr_err("Cannot open FDT image in FIT image: %m\n");
> +			return ret;
> +		}
> +	} else {
> +		if (!data->oftree_file)
> +			return 0;
> +
> +		pr_info("Loading devicetree from '%s'\n", data->oftree_file);
> +
> +		of_tree = read_file(data->oftree_file, &of_size);
> +		if (!of_tree) {
> +			ret = -errno;
> +			pr_err("Failed to read oftree: %m\n");
> +			return ret;
> +		}
>  	}
>  
>  	efiret = BS->allocate_pages(EFI_ALLOCATE_ANY_PAGES,

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