[PATCH v4 3/5] boot: android: Add bootconfig support
Guillaume La Roque (TI.com)
glaroque at baylibre.com
Thu Dec 18 12:16:58 CET 2025
For android vendor boot image version 4 bootconfig is mandatory.[1]
In the android_image_get_ramdisk function, after copying both vendor and
boot ramdisks, we extract all androidboot.* entries from the kernel
command line. These entries are added to the bootconfig section.
We then update the sizes of the ramdisk and bootconfig.
Finally, all androidboot.* entries are removed from the kernel command
line.
[1] https://source.android.com/docs/core/architecture/partitions/vendor-boot-partitions#bootloader-support
Reviewed-by: Simon Glass <sjg at chromium.org>
Signed-off-by: Guillaume La Roque (TI.com) <glaroque at baylibre.com>
---
boot/image-android.c | 174 +++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 163 insertions(+), 11 deletions(-)
diff --git a/boot/image-android.c b/boot/image-android.c
index 48886f39e4c..76600aec863 100644
--- a/boot/image-android.c
+++ b/boot/image-android.c
@@ -505,6 +505,166 @@ ulong android_image_get_kcomp(const void *hdr,
return image_decomp_type(p, sizeof(u32));
}
+/**
+ * android_boot_append_bootconfig() - Append bootconfig parameters to ramdisk
+ * @img_data: Pointer to Android image data
+ * @params: Pointer to boot config parameters to append
+ * @params_len: Length of boot config parameters
+ * @ramdisk_dest: Destination address for the merged ramdisk
+ *
+ * This function copies the vendor ramdisk, boot ramdisk, and bootconfig to
+ * the destination. It then appends the provided bootconfig parameters.
+ *
+ * Return: Bytes added to the bootconfig on success, negative on error.
+ */
+static long android_boot_append_bootconfig(const struct andr_image_data *img_data,
+ char *params, long params_len,
+ void *ramdisk_dest)
+{
+ void *vendor_ramdisk_src;
+ void *boot_ramdisk_src;
+ void *bootconfig_src;
+ long bytes_added = 0;
+
+ /* Map sources */
+ vendor_ramdisk_src = map_sysmem(img_data->vendor_ramdisk_ptr,
+ img_data->vendor_ramdisk_size);
+ boot_ramdisk_src = map_sysmem(img_data->ramdisk_ptr,
+ img_data->boot_ramdisk_size);
+
+ /* Copy Vendor Ramdisk */
+ memcpy(ramdisk_dest, vendor_ramdisk_src, img_data->vendor_ramdisk_size);
+
+ /* Copy Boot Ramdisk */
+ memcpy((char *)ramdisk_dest + img_data->vendor_ramdisk_size,
+ boot_ramdisk_src, img_data->boot_ramdisk_size);
+
+ /* Copy Bootconfig and Append Params */
+ if (img_data->bootconfig_size) {
+ bootconfig_src = map_sysmem(img_data->bootconfig_addr,
+ img_data->bootconfig_size);
+ memcpy((char *)ramdisk_dest + img_data->vendor_ramdisk_size +
+ img_data->boot_ramdisk_size,
+ bootconfig_src, img_data->bootconfig_size);
+ unmap_sysmem(bootconfig_src);
+
+ if (params && params_len > 1) {
+ void *bootconfig_ptr = (char *)ramdisk_dest +
+ img_data->vendor_ramdisk_size +
+ img_data->boot_ramdisk_size;
+ bytes_added = add_bootconfig_parameters(params, params_len,
+ (ulong)bootconfig_ptr,
+ img_data->bootconfig_size);
+ }
+ }
+
+ unmap_sysmem(boot_ramdisk_src);
+ unmap_sysmem(vendor_ramdisk_src);
+
+ if (bytes_added < 0)
+ return bytes_added;
+
+ return bytes_added;
+}
+
+/**
+ * android_image_set_bootconfig() - Extract androidboot.* args and append to bootconfig
+ * @hdr: Pointer to boot image header
+ * @vendor_boot_img: Pointer to vendor boot image header
+ * @ramdisk_addr: Destination address for the merged ramdisk
+ *
+ * Return: Size of the bootconfig section (including new params) on success, negative on error.
+ */
+static long android_image_set_bootconfig(const void *hdr,
+ const void *vendor_boot_img,
+ ulong ramdisk_addr)
+{
+ const char *bootargs = env_get("bootargs");
+ char *params = NULL;
+ char *new_bootargs = NULL;
+ long params_len = 0; /* Renamed from androidboot_params_len */
+ struct andr_image_data img_data;
+ long ret;
+ size_t len;
+ const char *src;
+ char *bc_dst;
+ char *args_dst;
+ ulong total_size;
+ void *ramdisk_dest;
+
+ if (!android_image_get_data(hdr, vendor_boot_img, &img_data))
+ return -EINVAL; /* Use errno */
+
+ /* Extract androidboot.* parameters from bootargs */
+ if (bootargs && img_data.bootconfig_size) {
+ len = strlen(bootargs);
+ src = bootargs;
+
+ params = malloc(len + 1);
+ new_bootargs = malloc(len + 1);
+ if (!params || !new_bootargs) {
+ free(params);
+ free(new_bootargs);
+ printf("Error: malloc failed\n");
+ return -ENOMEM;
+ }
+
+ bc_dst = params;
+ args_dst = new_bootargs;
+
+ /* Extract androidboot.* and build new bootargs in one pass */
+ while (*src) {
+ /* Skip leading spaces */
+ while (*src == ' ')
+ src++;
+ if (!*src)
+ break;
+
+ /* Check if this param starts with androidboot. */
+ if (strncmp(src, "androidboot.", 12) == 0) {
+ /* Copy to bootconfig (add newline if not first) */
+ if (bc_dst != params)
+ *bc_dst++ = '\n';
+ while (*src && *src != ' ')
+ *bc_dst++ = *src++;
+ } else {
+ /* Copy to new bootargs (add space if not first) */
+ if (args_dst != new_bootargs)
+ *args_dst++ = ' ';
+ while (*src && *src != ' ')
+ *args_dst++ = *src++;
+ }
+ }
+
+ *bc_dst++ = '\n'; /* Final newline for bootconfig */
+ *bc_dst = '\0';
+ *args_dst = '\0';
+ params_len = bc_dst - params;
+
+ /* Update bootargs if we extracted any androidboot params */
+ if (params_len > 1)
+ env_set("bootargs", new_bootargs);
+ }
+
+ /* Calculate total size for mapping */
+ total_size = img_data.ramdisk_size + img_data.bootconfig_size;
+ if (params_len > 1)
+ total_size += params_len + BOOTCONFIG_TRAILER_SIZE;
+
+ /* Map Dest */
+ ramdisk_dest = map_sysmem(ramdisk_addr, total_size);
+
+ /* Copy data */
+ ret = android_boot_append_bootconfig(&img_data, params, params_len,
+ ramdisk_dest);
+
+ unmap_sysmem(ramdisk_dest);
+ free(params);
+ free(new_bootargs);
+
+ return ret;
+}
+
int android_image_get_ramdisk(const void *hdr, const void *vendor_boot_img,
ulong *rd_data, ulong *rd_len)
{
@@ -536,17 +696,9 @@ int android_image_get_ramdisk(const void *hdr, const void *vendor_boot_img,
ramdisk_ptr = img_data.ramdisk_addr;
}
*rd_data = ramdisk_ptr;
- memcpy((void *)(ramdisk_ptr), (void *)img_data.vendor_ramdisk_ptr,
- img_data.vendor_ramdisk_size);
- ramdisk_ptr += img_data.vendor_ramdisk_size;
- memcpy((void *)(ramdisk_ptr), (void *)img_data.ramdisk_ptr,
- img_data.boot_ramdisk_size);
- ramdisk_ptr += img_data.boot_ramdisk_size;
- if (img_data.bootconfig_size) {
- memcpy((void *)
- (ramdisk_ptr), (void *)img_data.bootconfig_addr,
- img_data.bootconfig_size);
- }
+ if (img_data.header_version > 3)
+ img_data.ramdisk_size +=
+ android_image_set_bootconfig(hdr, vendor_boot_img, ramdisk_ptr);
} else {
/* Ramdisk can be used in-place, use current ptr */
if (img_data.ramdisk_addr == 0 ||
--
2.34.1
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