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boot: android: Add bootconfig support

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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@chromium.org>
Signed-off-by: Guillaume La Roque (TI.com) <glaroque@baylibre.com>
Link: https://lore.kernel.org/r/20260112-bootconfig-v5-3-79b242159ac7@baylibre.com
[mkorpershoek: dropped irrelevant code comments]
Signed-off-by: Mattijs Korpershoek <mkorpershoek@kernel.org>
This commit is contained in:
Guillaume La Roque (TI.com)
2026-01-12 11:55:39 +01:00
committed by Mattijs Korpershoek
parent 8f6d435570
commit 733f5a6019
1 changed files with 163 additions and 11 deletions
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174
boot/image-android.c
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@@ -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;
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;
/* 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 ||