]> git.dujemihanovic.xyz Git - u-boot.git/commitdiff
bootstd: Add a simple bootmeth for ChromiumOS
authorSimon Glass <sjg@chromium.org>
Wed, 12 Jul 2023 15:04:45 +0000 (09:04 -0600)
committerBin Meng <bmeng@tinylab.org>
Mon, 17 Jul 2023 05:38:35 +0000 (13:38 +0800)
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>
boot/Kconfig
boot/Makefile
boot/bootmeth_cros.c [new file with mode: 0644]
configs/tools-only_defconfig

index c8b8f36d83586dfc20ac9c72f9e6e6d75c1aa512..b424265df8dbc1e93d4e902ca5580df2e16ffef7 100644 (file)
@@ -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
index f828f870a37b023e4de2391c7d2a334ce7caa456..10f01572237893ebcb7aa7d1a86c0c0fc69136bc 100644 (file)
@@ -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 (file)
index 0000000..aa19ae0
--- /dev/null
@@ -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,
+};
index 2bc3bd9e912c521f0dd098d733a5a25ebae3c384..3f588ea69bee18f21c393c3493de6289d28e3387 100644 (file)
@@ -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"