[PATCH v2 3/5] boot: android: Add bootconfig support

Guillaume La Roque (TI.com) glaroque at baylibre.com
Fri Oct 17 15:19:19 CEST 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.

Signed-off-by: Guillaume La Roque (TI.com) <glaroque at baylibre.com>
---
 boot/image-android.c | 101 +++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 93 insertions(+), 8 deletions(-)

diff --git a/boot/image-android.c b/boot/image-android.c
index 613f2aa4b9e..cf038a4a62f 100644
--- a/boot/image-android.c
+++ b/boot/image-android.c
@@ -534,17 +534,102 @@ 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,
+
+		/* Extract androidboot.* parameters from bootargs */
+		const char *bootargs = env_get("bootargs");
+		char *androidboot_params = NULL;
+		char *new_bootargs = NULL;
+		size_t androidboot_params_len = 0;
+
+		if (bootargs && img_data.bootconfig_size) {
+			size_t len = strlen(bootargs);
+
+			androidboot_params = malloc(len + 1);
+			new_bootargs = malloc(len + 1);
+			if (!androidboot_params || !new_bootargs) {
+				free(androidboot_params);
+				free(new_bootargs);
+				printf("Error: malloc failed\n");
+				return -ENOMEM;
+			}
+
+			/* Extract androidboot.* and build new bootargs in one pass */
+			const char *src = bootargs;
+			char *bc_dst = androidboot_params;
+			char *args_dst = new_bootargs;
+
+			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 != androidboot_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';
+			androidboot_params_len = bc_dst - androidboot_params;
+
+			/* Update bootargs if we extracted any androidboot params */
+			if (androidboot_params_len > 1)
+				env_set("bootargs", new_bootargs);
+		}
+
+		/* Map addresses for memcpy operations */
+		void *ramdisk_dest = map_sysmem(ramdisk_ptr, img_data.ramdisk_size);
+		void *vendor_ramdisk_src = map_sysmem(img_data.vendor_ramdisk_ptr,
+						      img_data.vendor_ramdisk_size);
+		void *boot_ramdisk_src = map_sysmem(img_data.ramdisk_ptr,
+						    img_data.boot_ramdisk_size);
+
+		memcpy(ramdisk_dest, vendor_ramdisk_src,
 		       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;
+		memcpy((char *)ramdisk_dest + img_data.vendor_ramdisk_size,
+		       boot_ramdisk_src, img_data.boot_ramdisk_size);
+
 		if (img_data.bootconfig_size) {
-			memcpy((void *)
-			       (ramdisk_ptr), (void *)img_data.bootconfig_addr,
-			       img_data.bootconfig_size);
+			void *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);
+
+			/* Add androidboot.* parameters to bootconfig */
+			if (androidboot_params && androidboot_params_len > 1) {
+				ulong bootconfig_ptr = (ulong)ramdisk_dest +
+						       img_data.vendor_ramdisk_size +
+						       img_data.boot_ramdisk_size;
+				img_data.ramdisk_size +=
+					add_bootconfig_parameters(androidboot_params,
+								  androidboot_params_len,
+								  bootconfig_ptr,
+								  img_data.bootconfig_size);
+			}
 		}
+
+		free(androidboot_params);
+		free(new_bootargs);
+
+		unmap_sysmem(boot_ramdisk_src);
+		unmap_sysmem(vendor_ramdisk_src);
+		unmap_sysmem(ramdisk_dest);
 	} else {
 		/* Ramdisk can be used in-place, use current ptr */
 		if (img_data.ramdisk_addr == 0 ||

-- 
2.34.1



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