[PATCH 16/18] bootstd: Add a simple bootmeth for ChromiumOS
Heinrich Schuchardt
xypron.glpk at gmx.de
Fri Apr 28 21:50:52 CEST 2023
On 4/28/23 21:18, Simon Glass wrote:
> 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.
What is missing for booting ChromeOS on arm64?
Best regards
Heinrich
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> 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 d95a2a70266..1dadd42f15e 100644
> --- a/boot/Kconfig
> +++ b/boot/Kconfig
> @@ -462,6 +462,17 @@ 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_DISTRO
> bool "Bootdev support for distro boot"
> select PXE_UTILS
> diff --git a/boot/Makefile b/boot/Makefile
> index 88193a1b60e..998a7f9c684 100644
> --- a/boot/Makefile
> +++ b/boot/Makefile
> @@ -27,6 +27,7 @@ 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_)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 00000000000..440737060fd
> --- /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 at 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_debug("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 23e1f0e9dba..7b6c07ffb02 100644
> --- a/configs/tools-only_defconfig
> +++ b/configs/tools-only_defconfig
> @@ -9,6 +9,7 @@ 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"
More information about the U-Boot
mailing list