It is possible to boot x86-based ChromeOS machines by parsing a table and locating the kernel and command line. Add a bootmeth for this.
Signed-off-by: Simon Glass sjg@chromium.org Reviewed-by: Bin Meng bmeng.cn@gmail.com ---
(no changes since v1)
boot/Kconfig | 11 ++ boot/Makefile | 1 + boot/bootmeth_cros.c | 212 +++++++++++++++++++++++++++++++++++ configs/tools-only_defconfig | 1 + 4 files changed, 225 insertions(+) create mode 100644 boot/bootmeth_cros.c
diff --git a/boot/Kconfig b/boot/Kconfig index eea5ed6040ff..98eb2ca94c8e 100644 --- a/boot/Kconfig +++ b/boot/Kconfig @@ -463,6 +463,17 @@ config BOOTMETH_GLOBAL EFI bootmgr, since they take full control over which bootdevs are selected to boot.
+config BOOTMETH_CROS + bool "Bootdev support for Chromium OS" + depends on X86 || SANDBOX + default y + help + Enables support for booting Chromium OS using bootdevs. This uses the + kernel A slot and obtains the kernel command line from the parameters + provided there. + + Note that only x86 devices are supported at present. + config BOOTMETH_EXTLINUX bool "Bootdev support for extlinux boot" select PXE_UTILS diff --git a/boot/Makefile b/boot/Makefile index f94c31d922de..6e4cdbd4ce28 100644 --- a/boot/Makefile +++ b/boot/Makefile @@ -27,6 +27,7 @@ obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += bootstd-uclass.o obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_EXTLINUX) += bootmeth_extlinux.o obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_EXTLINUX_PXE) += bootmeth_pxe.o obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_EFILOADER) += bootmeth_efi.o +obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_CROS) += bootmeth_cros.o obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_SANDBOX) += bootmeth_sandbox.o obj-$(CONFIG_$(SPL_TPL_)BOOTMETH_SCRIPT) += bootmeth_script.o ifdef CONFIG_$(SPL_TPL_)BOOTSTD_FULL diff --git a/boot/bootmeth_cros.c b/boot/bootmeth_cros.c new file mode 100644 index 000000000000..aa19ae097f56 --- /dev/null +++ b/boot/bootmeth_cros.c @@ -0,0 +1,212 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Bootmethod for ChromiumOS + * + * Copyright 2023 Google LLC + * Written by Simon Glass sjg@chromium.org + */ + +#define LOG_CATEGORY UCLASS_BOOTSTD + +#include <common.h> +#include <blk.h> +#include <bootdev.h> +#include <bootflow.h> +#include <bootmeth.h> +#include <dm.h> +#include <malloc.h> +#include <mapmem.h> +#include <part.h> +#ifdef CONFIG_X86 +#include <asm/zimage.h> +#endif +#include <linux/sizes.h> + +enum { + /* Offsets in the kernel-partition header */ + KERN_START = 0x4f0, + KERN_SIZE = 0x518, + + SETUP_OFFSET = 0x1000, /* bytes before base */ + CMDLINE_OFFSET = 0x2000, /* bytes before base */ + OFFSET_BASE = 0x100000, /* assumed kernel load-address */ +}; + +static int cros_check(struct udevice *dev, struct bootflow_iter *iter) +{ + /* This only works on block and network devices */ + if (bootflow_iter_check_blk(iter)) + return log_msg_ret("blk", -ENOTSUPP); + + return 0; +} + +static int copy_cmdline(const char *from, const char *uuid, char **bufp) +{ + const int maxlen = 2048; + char buf[maxlen]; + char *cmd, *to, *end; + int len; + + /* Allow space for cmdline + UUID */ + len = strnlen(from, sizeof(buf)); + if (len >= maxlen) + return -E2BIG; + + log_debug("uuid %d %s\n", uuid ? (int)strlen(uuid) : 0, uuid); + for (to = buf, end = buf + maxlen - UUID_STR_LEN - 1; *from; from++) { + if (to >= end) + return -E2BIG; + if (from[0] == '%' && from[1] == 'U' && uuid && + strlen(uuid) == UUID_STR_LEN) { + strcpy(to, uuid); + to += UUID_STR_LEN; + from++; + } else { + *to++ = *from; + } + } + *to = '\0'; + len = to - buf; + cmd = strdup(buf); + if (!cmd) + return -ENOMEM; + free(*bufp); + *bufp = cmd; + + return 0; +} + +static int cros_read_bootflow(struct udevice *dev, struct bootflow *bflow) +{ + struct blk_desc *desc = dev_get_uclass_plat(bflow->blk); + ulong base, start, size, setup, cmdline, num_blks, kern_base; + struct disk_partition info; + const char *uuid = NULL; + void *buf, *hdr; + int ret; + + log_debug("starting, part=%d\n", bflow->part); + + /* We consider the whole disk, not any one partition */ + if (bflow->part) + return log_msg_ret("max", -ENOENT); + + /* Check partition 2 */ + ret = part_get_info(desc, 2, &info); + if (ret) + return log_msg_ret("part", ret); + + /* Make a buffer for the header information */ + num_blks = SZ_4K >> desc->log2blksz; + log_debug("Reading header, blk=%s, start=%lx, blocks=%lx\n", + bflow->blk->name, (ulong)info.start, num_blks); + hdr = memalign(SZ_1K, SZ_4K); + if (!hdr) + return log_msg_ret("hdr", -ENOMEM); + ret = blk_read(bflow->blk, info.start, num_blks, hdr); + if (ret != num_blks) + return log_msg_ret("inf", ret); + + if (memcmp("CHROMEOS", hdr, 8)) + return -ENOENT; + + log_info("Header at %lx\n", (ulong)map_to_sysmem(hdr)); + start = *(u32 *)(hdr + KERN_START); + size = ALIGN(*(u32 *)(hdr + KERN_SIZE), desc->blksz); + log_debug("Reading start %lx size %lx\n", start, size); + bflow->size = size; + + buf = memalign(SZ_1K, size); + if (!buf) + return log_msg_ret("buf", -ENOMEM); + num_blks = size >> desc->log2blksz; + log_debug("Reading data, blk=%s, start=%lx, blocks=%lx\n", + bflow->blk->name, (ulong)info.start, num_blks); + ret = blk_read(bflow->blk, (ulong)info.start + 0x80, num_blks, buf); + if (ret != num_blks) + return log_msg_ret("inf", ret); + base = map_to_sysmem(buf); + + setup = base + start - OFFSET_BASE - SETUP_OFFSET; + cmdline = base + start - OFFSET_BASE - CMDLINE_OFFSET; + kern_base = base + start - OFFSET_BASE + SZ_16K; + log_debug("base %lx setup %lx, cmdline %lx, kern_base %lx\n", base, + setup, cmdline, kern_base); + +#ifdef CONFIG_X86 + const char *version; + + version = zimage_get_kernel_version(map_sysmem(setup, 0), + map_sysmem(kern_base, 0)); + log_debug("version %s\n", version); + if (version) + bflow->name = strdup(version); +#endif + if (!bflow->name) + bflow->name = strdup("ChromeOS"); + if (!bflow->name) + return log_msg_ret("nam", -ENOMEM); + bflow->os_name = strdup("ChromeOS"); + if (!bflow->os_name) + return log_msg_ret("os", -ENOMEM); + +#if CONFIG_IS_ENABLED(PARTITION_UUIDS) + uuid = info.uuid; +#endif + ret = copy_cmdline(map_sysmem(cmdline, 0), uuid, &bflow->cmdline); + if (ret) + return log_msg_ret("cmd", ret); + + bflow->state = BOOTFLOWST_READY; + bflow->buf = buf; + bflow->x86_setup = map_sysmem(setup, 0); + + return 0; +} + +static int cros_read_file(struct udevice *dev, struct bootflow *bflow, + const char *file_path, ulong addr, ulong *sizep) +{ + return -ENOSYS; +} + +static int cros_boot(struct udevice *dev, struct bootflow *bflow) +{ +#ifdef CONFIG_X86 + zboot_start(map_to_sysmem(bflow->buf), bflow->size, 0, 0, + map_to_sysmem(bflow->x86_setup), + bflow->cmdline); +#endif + + return log_msg_ret("go", -EFAULT); +} + +static int cros_bootmeth_bind(struct udevice *dev) +{ + struct bootmeth_uc_plat *plat = dev_get_uclass_plat(dev); + + plat->desc = "ChromiumOS boot"; + + return 0; +} + +static struct bootmeth_ops cros_bootmeth_ops = { + .check = cros_check, + .read_bootflow = cros_read_bootflow, + .read_file = cros_read_file, + .boot = cros_boot, +}; + +static const struct udevice_id cros_bootmeth_ids[] = { + { .compatible = "u-boot,cros" }, + { } +}; + +U_BOOT_DRIVER(bootmeth_cros) = { + .name = "bootmeth_cros", + .id = UCLASS_BOOTMETH, + .of_match = cros_bootmeth_ids, + .ops = &cros_bootmeth_ops, + .bind = cros_bootmeth_bind, +}; diff --git a/configs/tools-only_defconfig b/configs/tools-only_defconfig index 2bc3bd9e912c..3f588ea69bee 100644 --- a/configs/tools-only_defconfig +++ b/configs/tools-only_defconfig @@ -10,6 +10,7 @@ CONFIG_FIT=y CONFIG_TIMESTAMP=y CONFIG_FIT_SIGNATURE=y # CONFIG_BOOTSTD_FULL is not set +# CONFIG_BOOTMETH_CROS is not set # CONFIG_BOOTMETH_VBE is not set CONFIG_USE_BOOTCOMMAND=y CONFIG_BOOTCOMMAND="run distro_bootcmd"