[PATCH v4 24/33] bootstd: Add an implementation of EFI boot

Simon Glass
2022-03-06T12:55:16Z

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@chromium.org>
---

Changes in v4:
- Allow use without a block device
- Fix 'a' typo
- Improve debugging in efiload_read_file()

Changes in v3:
- Add a log category
- Align the EFI load address
- Use a short name when BOOTSTD_FULL is not enabled
- Use common bootmeth functions

boot/Kconfig | 21 +++++
boot/Makefile | 1 +
boot/bootmeth_efi.c | 188 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 210 insertions(+)
create mode 100644 boot/bootmeth_efi.c

diff --git a/boot/Kconfig b/boot/Kconfig
index 15b5e2e99b..d434048deb 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -349,6 +349,27 @@ 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 170fcac8ec..c234543520 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 0000000000..d5438eb67b
--- /dev/null
+++ b/boot/bootmeth_efi.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootmethod for distro boot via EFI
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <sjg@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;
+ const char *dev_name;
+ 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, %s, %p, %x\n",
+ dev_get_uclass_name(media_dev), devnum_str, bflow->fname,
+ bflow->buf, size);
+ dev_name = device_get_uclass_id(media_dev) == UCLASS_MASS_STORAGE ?
+ "usb" : dev_get_uclass_name(media_dev);
+ efi_set_bootdev(dev_name, 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 = NULL;
+ 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);
+
+ if (bflow->blk)
+ desc = dev_get_uclass_plat(bflow->blk);
+ 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 an .efi file" : "EFI";
+
+ 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,
+};
+
+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,
+};
--
2.35.1.616.g0bdcbb4464-goog