[PATCH v3 22/31] bootstd: Add an implementation of EFI boot

[Heinrich Schuchardt]

On 1/19/22 02:43, Simon Glass wrote:
> Add a bootmeth driver which handles EFI boot, using EFI_LOADER.
>
> In effect, this provides the same functionality as the 'bootefi' command
> and shares the same code. But the interface into it is via a bootmeth,
> so it does not require any special scripts, etc.
>
> For now this requires the 'bootefi' command be enabled. Future work may
> tidy this up so that it can be used without CONFIG_CMDLINE being enabled.
>
> There was much discussion about whether this is needed, but it seems
> that it is, at least for now.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> Changes in v3:
> - Add a log category
> - Use a short name when BOOTSTD_FULL is not enabled
> - Align the EFI load address
> - Use common bootmeth functions
>
>   boot/Kconfig        |  21 +++++
>   boot/Makefile       |   1 +
>   boot/bootmeth_efi.c | 183 ++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 205 insertions(+)
>   create mode 100644 boot/bootmeth_efi.c
>
> diff --git a/boot/Kconfig b/boot/Kconfig
> index 61df705141d..0fee35070b0 100644
> --- a/boot/Kconfig
> +++ b/boot/Kconfig
> @@ -338,6 +338,27 @@ config BOOTMETH_DISTRO_PXE
>
>   	  This provides a way to try out standard boot on an existing boot flow.
>
> +config BOOTMETH_EFILOADER
> +	bool "Bootdev support for EFI boot"
> +	depends on CMD_BOOTEFI
> +	default y
> +	help
> +	  Enables support for EFI boot using bootdevs. This makes the
> +	  bootdevs look for a 'boot<arch>.efi' on each filesystem
> +	  they scan. The resulting file is booted after enabling U-Boot's
> +	  EFI loader support.
> +
> +	  The <arch> depends on the architecture of the board:
> +
> +	     aa64      - aarch64 (ARM 64-bit)
> +	     arm       - ARM 32-bit
> +	     ia32      - x86 32-bit
> +	     x64       - x86 64-bit
> +	     riscv32   - RISC-V 32-bit
> +	     riscv64   - RISC-V 64-bit
> +
> +	  This provides a way to try out standard boot on an existing boot flow.
> +
>   endif
>
>   config LEGACY_IMAGE_FORMAT
> diff --git a/boot/Makefile b/boot/Makefile
> index 170fcac8ec4..c2345435201 100644
> --- a/boot/Makefile
> +++ b/boot/Makefile
> @@ -30,6 +30,7 @@ obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += bootstd-uclass.o
>
>   obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_DISTRO) += bootmeth_distro.o
>   obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_DISTRO_PXE) += bootmeth_pxe.o
> +obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_EFILOADER) += bootmeth_efi.o
>
>   obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += image-fdt.o
>   obj-$(CONFIG_$(SPL_TPL_)FIT_SIGNATURE) += fdt_region.o
> diff --git a/boot/bootmeth_efi.c b/boot/bootmeth_efi.c
> new file mode 100644
> index 00000000000..4c0c3494c3b
> --- /dev/null
> +++ b/boot/bootmeth_efi.c
> @@ -0,0 +1,183 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Bootmethod for distro boot via EFI
> + *
> + * Copyright 2021 Google LLC
> + * Written by Simon Glass <sjg at chromium.org>
> + */
> +
> +#define LOG_CATEGORY UCLASS_BOOTSTD
> +
> +#include <common.h>
> +#include <bootdev.h>
> +#include <bootflow.h>
> +#include <bootmeth.h>
> +#include <command.h>
> +#include <dm.h>
> +#include <efi_loader.h>
> +#include <fs.h>
> +#include <malloc.h>
> +#include <mapmem.h>
> +#include <mmc.h>
> +#include <pxe_utils.h>
> +
> +#define EFI_DIRNAME	"efi/boot/"
> +
> +/**
> + * get_efi_leafname() - Get the leaf name for the EFI file we expect
> + *
> + * @str: Place to put leaf name for this architecture, e.g. "bootaa64.efi".
> + *	Must have at least 16 bytes of space
> + * @max_len: Length of @str, must be >=16
> + */
> +static int get_efi_leafname(char *str, int max_len)
> +{
> +	const char *base;
> +
> +	if (max_len < 16)
> +		return log_msg_ret("spc", -ENOSPC);
> +	if (IS_ENABLED(CONFIG_ARM64))
> +		base = "bootaa64";
> +	else if (IS_ENABLED(CONFIG_ARM))
> +		base = "bootarm";
> +	else if (IS_ENABLED(CONFIG_X86_RUN_32BIT))
> +		base = "bootia32";
> +	else if (IS_ENABLED(CONFIG_X86_RUN_64BIT))
> +		base = "bootx64";
> +	else if (IS_ENABLED(CONFIG_ARCH_RV32I))
> +		base = "bootriscv32";
> +	else if (IS_ENABLED(CONFIG_ARCH_RV64I))
> +		base = "bootriscv64";
> +	else if (IS_ENABLED(CONFIG_SANDBOX))
> +		base = "bootsbox";
> +	else
> +		return -EINVAL;
> +
> +	strcpy(str, base);
> +	strcat(str, ".efi");
> +
> +	return 0;
> +}
> +
> +static int efiload_read_file(struct blk_desc *desc, struct bootflow *bflow)
> +{
> +	const struct udevice *media_dev;
> +	int size = bflow->size;
> +	char devnum_str[9];
> +	char dirname[200];
> +	char *last_slash;
> +	int ret;
> +
> +	ret = bootmeth_alloc_file(bflow, 0x2000000, 0x10000);
> +	if (ret)
> +		return log_msg_ret("read", ret);
> +
> +	/*
> +	 * This is a horrible hack to tell EFI about this boot device. Once we
> +	 * unify EFI with the rest of U-Boot we can clean this up. The same hack
> +	 * exists in multiple places, e.g. in the fs, tftp and load commands.
> +	 *
> +	 * Once we can clean up the EFI code to make proper use of driver model,
> +	 * this can go away.
> +	 */
> +	media_dev = dev_get_parent(bflow->dev);
> +	snprintf(devnum_str, sizeof(devnum_str), "%x", dev_seq(media_dev));
> +
> +	strlcpy(dirname, bflow->fname, sizeof(dirname));
> +	last_slash = strrchr(dirname, '/');
> +	if (last_slash)
> +		*last_slash = '\0';
> +
> +	log_debug("setting bootdev %s, %s\n", dev_get_uclass_name(media_dev),
> +		  bflow->fname);
> +	efi_set_bootdev(dev_get_uclass_name(media_dev), devnum_str,
> +			bflow->fname, bflow->buf, size);
> +
> +	return 0;
> +}
> +
> +static int distro_efi_check(struct udevice *dev, struct bootflow_iter *iter)
> +{
> +	int ret;
> +
> +	/* This only works on block devices */
> +	ret = bootflow_iter_uses_blk_dev(iter);
> +	if (ret)
> +		return log_msg_ret("blk", ret);
> +
> +	return 0;
> +}
> +
> +static int distro_efi_read_bootflow(struct udevice *dev, struct bootflow *bflow)
> +{
> +	struct blk_desc *desc = dev_get_uclass_plat(bflow->blk);
> +	char fname[sizeof(EFI_DIRNAME) + 16];
> +	int ret;
> +
> +	/* We require a partition table */
> +	if (!bflow->part)
> +		return -ENOENT;
> +
> +	strcpy(fname, EFI_DIRNAME);
> +	ret = get_efi_leafname(fname + strlen(fname),
> +			       sizeof(fname) - strlen(fname));
> +	if (ret)
> +		return log_msg_ret("leaf", ret);
> +
> +	ret = bootmeth_try_file(bflow, desc, NULL, fname);
> +	if (ret)
> +		return log_msg_ret("try", ret);
> +
> +	ret = efiload_read_file(desc, bflow);
> +	if (ret)
> +		return log_msg_ret("read", -EINVAL);
> +
> +	return 0;
> +}
> +
> +int distro_efi_boot(struct udevice *dev, struct bootflow *bflow)
> +{
> +	char cmd[50];
> +
> +	/*
> +	 * At some point we can add a real interface to bootefi so we can call
> +	 * this directly. For now, go through the CLI like distro boot.
> +	 */
> +	snprintf(cmd, sizeof(cmd), "bootefi %lx %lx",
> +		 (ulong)map_to_sysmem(bflow->buf),
> +		 (ulong)map_to_sysmem(gd->fdt_blob));
> +	if (run_command(cmd, 0))
> +		return log_msg_ret("run", -EINVAL);
> +
> +	return 0;
> +}
> +
> +static int distro_bootmeth_efi_bind(struct udevice *dev)
> +{
> +	struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev);
> +
> +	plat->desc = IS_ENABLED(CONFIG_BOOTSTD_FULL) ?
> +		"EFI boot from a .efi file" : "EFI";

nits:
%s/a/an/

> +
> +	return 0;
> +}
> +
> +static struct bootmeth_ops distro_efi_bootmeth_ops = {
> +	.check		= distro_efi_check,
> +	.read_bootflow	= distro_efi_read_bootflow,
> +	.read_file	= bootmeth_common_read_file,
> +	.boot		= distro_efi_boot,
> +};

Where is the device tree read?

Best regards

Heinrich

> +
> +static const struct udevice_id distro_efi_bootmeth_ids[] = {
> +	{ .compatible = "u-boot,distro-efi" },
> +	{ }
> +};
> +
> +U_BOOT_DRIVER(bootmeth_efi) = {
> +	.name		= "bootmeth_efi",
> +	.id		= UCLASS_BOOTMETH,
> +	.of_match	= distro_efi_bootmeth_ids,
> +	.ops		= &distro_efi_bootmeth_ops,
> +	.bind		= distro_bootmeth_efi_bind,
> +};