[PATCH v8 5/7] efi_loader: support boot from URI device path
Ilias Apalodimas
ilias.apalodimas at linaro.org
Thu Oct 26 21:34:59 CEST 2023
Kojima-san,
Thanks the device path handling seems saner in this version.
On Wed, 25 Oct 2023 at 09:30, Masahisa Kojima
<masahisa.kojima at linaro.org> wrote:
>
> This supports to boot from the URI device path.
> When user selects the URI device path, bootmgr downloads
> the file using wget into the address specified by loadaddr
> env variable.
> If the file is .iso or .img file, mount the image with blkmap
> then try to boot with the default file(e.g. EFI/BOOT/BOOTAA64.EFI).
> Since boot option indicating the default file is automatically
> created when new disk is detected, system can boot by selecting
> the automatically created blkmap boot option.
> If the file is PE-COFF file, load and start the downloaded file.
>
> The buffer used to download the ISO image file must be
> reserved to avoid the unintended access to the image and
> expose the ramdisk to the OS.
> For PE-COFF file case, this memory reservation is done
> in LoadImage Boot Service.
>
> Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
> ---
> cmd/bootefi.c | 5 +
> include/efi_loader.h | 1 +
> lib/efi_loader/Kconfig | 9 ++
> lib/efi_loader/efi_bootmgr.c | 229 +++++++++++++++++++++++++++++++++++
> 4 files changed, 244 insertions(+)
>
> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
> index 20e5c94a33..74203ec5b6 100644
> --- a/cmd/bootefi.c
> +++ b/cmd/bootefi.c
> @@ -394,6 +394,11 @@ out:
> log_err("Failed to remove loadfile2 for initrd\n");
> }
>
> + if (IS_ENABLED(CONFIG_EFI_HTTP_BOOT)) {
> + if (efi_bootmgr_release_ramdisk() != EFI_SUCCESS)
> + log_err("Failed to remove ramdisk\n");
> + }
> +
So, I know I am the one who did this first and removed the loadfile2
protocol by calling a function in a boot failure.
I didn't like it back then either but we didn't have events. I think
it's best if we define an event for reverting the memory changes
instead of calling functions (and I will fix the same thing for
loadfile2 protocol destruction)
Heinrich what do you think?
> /* Control is returned to U-Boot, disable EFI watchdog */
> efi_set_watchdog(0);
>
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index e24410505f..2fea1f17fb 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -937,6 +937,7 @@ efi_status_t efi_set_load_options(efi_handle_t handle,
> efi_uintn_t load_options_size,
> void *load_options);
> efi_status_t efi_bootmgr_load(efi_handle_t *handle, void **load_options);
[...]
>
> +#include <blk.h>
> +#include <blkmap.h>
> #include <common.h>
> #include <charset.h>
> +#include <dm.h>
> #include <log.h>
> #include <malloc.h>
> +#include <net.h>
> #include <efi_default_filename.h>
> #include <efi_loader.h>
> #include <efi_variable.h>
> @@ -19,6 +23,10 @@
> static const struct efi_boot_services *bs;
> static const struct efi_runtime_services *rs;
>
> +static u32 image_size;
> +static ulong image_addr;
> +static struct udevice *ramdisk_blk_dev = NULL;
> +
> const efi_guid_t efi_guid_bootmenu_auto_generated =
> EFICONFIG_AUTO_GENERATED_ENTRY_GUID;
>
> @@ -168,6 +176,197 @@ out:
> return ret;
> }
>
> +/**
> + * mount_image() - mount the image with blkmap
> + *
> + * @lo_label: u16 label string of load option
> + * @addr: image address
> + * @size: image size
> + * Return: pointer to the UCLASS_BLK udevice, NULL if failed
> + */
> +static struct udevice *mount_image(u16 *lo_label, ulong addr, int size)
> +{
> + int err;
> + struct blkmap *bm;
> + struct udevice *bm_dev;
> + char *label = NULL, *p;
> +
> + label = efi_alloc(utf16_utf8_strlen(lo_label) + 1);
> + if (!label)
> + return NULL;
> +
> + p = label;
> + utf16_utf8_strcpy(&p, lo_label);
> + err = blkmap_create_ramdisk(label, addr, size, &bm_dev);
> + if (err) {
> + efi_free_pool(label);
> + return NULL;
> + }
> + bm = dev_get_plat(bm_dev);
> +
> + efi_free_pool(label);
> +
> + return bm->blk;
> +}
> +
> +/**
> + * try_load_default_file() - try to load the default file
> + *
> + * Search the device having EFI_SIMPLE_FILE_SYSTEM_PROTOCOL,
> + * then try to load with the default boot file(e.g. EFI/BOOT/BOOTAA64.EFI).
> + *
> + * @dev pointer to the UCLASS_BLK or UCLASS_PARTITION udevice
> + * @image_handle: pointer to handle for newly installed image
> + * Return: status code
> + */
> +static efi_status_t try_load_default_file(struct udevice *dev,
> + efi_handle_t *image_handle)
> +{
> + efi_status_t ret;
> + efi_handle_t handle;
> + struct efi_handler *handler;
> + struct efi_device_path *file_path;
> + struct efi_device_path *device_path;
> +
> + if (dev_tag_get_ptr(dev, DM_TAG_EFI, (void **)&handle)) {
> + log_warning("DM_TAG_EFI not found\n");
> + return EFI_INVALID_PARAMETER;
> + }
> +
> + ret = efi_search_protocol(handle,
> + &efi_simple_file_system_protocol_guid, &handler);
> + if (ret != EFI_SUCCESS)
> + return ret;
nit; but do we really need this check? Or is it just to fail early
before efi_load_image() gets called?
> +
> + ret = EFI_CALL(bs->open_protocol(handle, &efi_guid_device_path,
> + (void **)&device_path, efi_root, NULL,
> + EFI_OPEN_PROTOCOL_GET_PROTOCOL));
> + if (ret != EFI_SUCCESS)
> + return ret;
> +
> + file_path = expand_media_path(device_path);
> + ret = EFI_CALL(efi_load_image(true, efi_root, file_path, NULL, 0,
> + image_handle));
> + efi_free_pool(file_path);
> +
> + return ret;
> +}
> +
> +/**
> + * load_default_file_from_blk_dev() - load the default file
> + *
> + * @blk pointer to the UCLASS_BLK udevice
> + * @handle: pointer to handle for newly installed image
> + * Return: status code
> + */
> +static efi_status_t load_default_file_from_blk_dev(struct udevice *blk,
> + efi_handle_t *handle)
> +{
> + efi_status_t ret;
> + struct udevice *partition;
> +
> + /* image that has no partition table but a file system */
> + ret = try_load_default_file(blk, handle);
> + if (ret == EFI_SUCCESS)
> + return ret;
> +
> + /* try the partitions */
> + device_foreach_child(partition, blk) {
> + enum uclass_id id;
> +
> + id = device_get_uclass_id(partition);
> + if (id != UCLASS_PARTITION)
> + continue;
> +
> + ret = try_load_default_file(partition, handle);
> + if (ret == EFI_SUCCESS)
> + return ret;
> + }
> +
> + return EFI_NOT_FOUND;
> +}
> +
> +/**
> + * try_load_from_uri_path() - Handle the URI device path
> + *
> + * @uridp: uri device path
> + * @lo_label: label of load option
> + * @handle: pointer to handle for newly installed image
> + * Return: status code
> + */
> +static efi_status_t try_load_from_uri_path(struct efi_device_path_uri *uridp,
> + u16 *lo_label,
> + efi_handle_t *handle)
> +{
> + char *s;
> + int err;
> + int uri_len;
> + efi_status_t ret;
> +
> + s = env_get("loadaddr");
> + if (!s) {
> + log_err("Error: loadaddr is not set\n");
> + return EFI_INVALID_PARAMETER;
> + }
> + image_addr = hextoul(s, NULL);
> + err = wget_with_dns(image_addr, uridp->uri);
> + if (err < 0)
> + return EFI_INVALID_PARAMETER;
> + image_size = env_get_hex("filesize", 0);
> + if (!image_size)
> + return EFI_INVALID_PARAMETER;
> +
> + /*
> + * If the file extension is ".iso" or ".img", mount it and try to load
> + * the default file.
> + * If the file is PE-COFF image, load the downloaded file.
> + */
> + uri_len = strlen(uridp->uri);
> + if (!strncmp(&uridp->uri[uri_len - 4], ".iso", 4) ||
> + !strncmp(&uridp->uri[uri_len - 4], ".img", 4)) {
> + struct udevice *blk;
> +
> + blk = mount_image(lo_label, image_addr, image_size);
> + if (!blk)
> + return EFI_LOAD_ERROR;
> +
> + ret = load_default_file_from_blk_dev(blk, handle);
> + if (ret != EFI_SUCCESS)
> + return ret;
> +
> + ramdisk_blk_dev = blk;
> +
> + /*
> + * TODO: expose the ramdisk to OS.
> + * Need to pass the ramdisk information by the architecture-specific
> + * methods such as 'pmem' device-tree node.
> + */
> + ret = efi_add_memory_map(image_addr, image_size,
> + EFI_RESERVED_MEMORY_TYPE);
> + if (ret != EFI_SUCCESS)
> + efi_bootmgr_release_ramdisk();
> + } else if (efi_check_pe((void *)image_addr, image_size, NULL) == EFI_SUCCESS) {
> + efi_handle_t mem_handle = NULL;
> + struct efi_device_path *file_path;
> +
> + file_path = efi_dp_from_mem(EFI_RESERVED_MEMORY_TYPE,
> + (uintptr_t)image_addr, image_size);
> + ret = efi_install_multiple_protocol_interfaces(
> + &mem_handle, &efi_guid_device_path, file_path, NULL);
> + if (ret != EFI_SUCCESS)
> + return ret;
> +
> + ret = EFI_CALL(efi_load_image(false, efi_root, file_path,
> + (void *)image_addr, image_size,
> + handle));
> + } else {
> + log_err("Error: file type is not supported\n");
> + return EFI_UNSUPPORTED;
> + }
> +
> + return ret;
> +}
> +
> /**
> * try_load_entry() - try to load image for boot option
> *
> @@ -211,6 +410,14 @@ static efi_status_t try_load_entry(u16 n, efi_handle_t *handle,
> if (EFI_DP_TYPE(lo.file_path, MEDIA_DEVICE, FILE_PATH)) {
> /* file_path doesn't contain a device path */
> ret = try_load_from_short_path(lo.file_path, handle);
> + } else if (EFI_DP_TYPE(lo.file_path, MESSAGING_DEVICE, MSG_URI)) {
> + if (IS_ENABLED(CONFIG_EFI_HTTP_BOOT))
> + ret = try_load_from_uri_path(
> + (struct efi_device_path_uri *)
> + lo.file_path,
> + lo.label, handle);
> + else
> + ret = EFI_LOAD_ERROR;
> } else {
> file_path = expand_media_path(lo.file_path);
> ret = EFI_CALL(efi_load_image(true, efi_root, file_path,
> @@ -345,6 +552,28 @@ error:
> return ret;
> }
>
> +/**
> + * efi_bootmgr_release_ramdisk() - release ramdisk resource
> + *
> + * Return: status code
> + */
> +efi_status_t efi_bootmgr_release_ramdisk(void)
> +{
> + efi_status_t ret = EFI_SUCCESS;
> +
> + if (ramdisk_blk_dev) {
> + ret = efi_add_memory_map(image_addr, image_size,
> + EFI_CONVENTIONAL_MEMORY);
> +
> + if (blkmap_destroy(ramdisk_blk_dev->parent))
> + ret = EFI_DEVICE_ERROR;
This seems a bit weird. We are changing the return error value on
multiple errors.
The efi_add_memory_map() shouldn't fail, unless something *really* bad
has happened.
Can we check for the return code in this and print an appropriate error?
This function also has 2 callers, one of them isn't checking the
return value. Again at least print a message so users are aware that
some memory cant be reclaimed
Thanks
/Ilias
> +
> + ramdisk_blk_dev = NULL;
> + }
> +
> + return ret;
> +}
> +
> /**
> * efi_bootmgr_enumerate_boot_option() - enumerate the possible bootable media
> *
> --
> 2.34.1
>
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