On 10/6/25 6:15 AM, [email protected] wrote:
> From: Ahmad Fatoum <[email protected]>
>
> 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 <[email protected]>
Reviewed-by: Ahmad Fatoum <[email protected]>
> ---
> 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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