boot image header v4

native/jni/magiskboot/bootimg.cpp

@@ -247,7 +247,15 @@ void boot_img::parse_image(uint8_t *addr, format_t type) {
     auto hp = reinterpret_cast<boot_img_hdr*>(addr);
     if (type == AOSP_VENDOR) {
         fprintf(stderr, "VENDOR_BOOT_HDR\n");
-        hdr = new dyn_img_vnd_v3(addr);
+        switch (hp->header_version) {
+        case 4:
+            hdr = new dyn_img_vnd_v4(addr);
+            break;
+        case 3:
+        default:
+            hdr = new dyn_img_vnd_v3(addr);
+            break;
+        }
     } else if (hp->page_size >= 0x02000000) {
         fprintf(stderr, "PXA_BOOT_HDR\n");
         hdr = new dyn_img_pxa(addr);
@@ -276,6 +284,9 @@ void boot_img::parse_image(uint8_t *addr, format_t type) {
         case 3:
             hdr = new dyn_img_v3(addr);
             break;
+        case 4:
+            hdr = new dyn_img_v4(addr);
+            break;
         default:
             hdr = new dyn_img_v0(addr);
             break;

native/jni/magiskboot/bootimg.hpp

@@ -104,6 +104,8 @@ struct AvbVBMetaImageHeader {
 #define BOOT_ARGS_SIZE 512
 #define BOOT_EXTRA_ARGS_SIZE 1024
 #define VENDOR_BOOT_ARGS_SIZE 2048
+#define VENDOR_RAMDISK_NAME_SIZE 32
+#define VENDOR_RAMDISK_TABLE_ENTRY_BOARD_ID_SIZE 16
 
 /*
  * +-----------------+
@@ -261,6 +263,101 @@ struct boot_img_hdr_vnd_v3 {
     uint64_t dtb_addr;      /* physical load address for DTB image */
 } __attribute__((packed));
 
+/* When the boot image header has a version of 4, the structure of the boot
+ * image is as follows:
+ *
+ * +---------------------+
+ * | boot header         | 4096 bytes
+ * +---------------------+
+ * | kernel              | m pages
+ * +---------------------+
+ * | ramdisk             | n pages
+ * +---------------------+
+ * | boot signature      | g pages
+ * +---------------------+
+ *
+ * m = (kernel_size + 4096 - 1) / 4096
+ * n = (ramdisk_size + 4096 - 1) / 4096
+ * g = (signature_size + 4096 - 1) / 4096
+ *
+ * Note that in version 4 of the boot image header, page size is fixed at 4096
+ * bytes.
+ *
+ * The structure of the vendor boot image version 4, which is required to be
+ * present when a version 4 boot image is used, is as follows:
+ *
+ * +------------------------+
+ * | vendor boot header     | o pages
+ * +------------------------+
+ * | vendor ramdisk section | p pages
+ * +------------------------+
+ * | dtb                    | q pages
+ * +------------------------+
+ * | vendor ramdisk table   | r pages
+ * +------------------------+
+ * | bootconfig             | s pages
+ * +------------------------+
+ *
+ * o = (2128 + page_size - 1) / page_size
+ * p = (vendor_ramdisk_size + page_size - 1) / page_size
+ * q = (dtb_size + page_size - 1) / page_size
+ * r = (vendor_ramdisk_table_size + page_size - 1) / page_size
+ * s = (vendor_bootconfig_size + page_size - 1) / page_size
+ *
+ * Note that in version 4 of the vendor boot image, multiple vendor ramdisks can
+ * be included in the vendor boot image. The bootloader can select a subset of
+ * ramdisks to load at runtime. To help the bootloader select the ramdisks, each
+ * ramdisk is tagged with a type tag and a set of hardware identifiers
+ * describing the board, soc or platform that this ramdisk is intended for.
+ *
+ * The vendor ramdisk section is consist of multiple ramdisk images concatenated
+ * one after another, and vendor_ramdisk_size is the size of the section, which
+ * is the total size of all the ramdisks included in the vendor boot image.
+ *
+ * The vendor ramdisk table holds the size, offset, type, name and hardware
+ * identifiers of each ramdisk. The type field denotes the type of its content.
+ * The vendor ramdisk names are unique. The hardware identifiers are specified
+ * in the board_id field in each table entry. The board_id field is consist of a
+ * vector of unsigned integer words, and the encoding scheme is defined by the
+ * hardware vendor.
+ *
+ * For the different type of ramdisks, there are:
+ *    - VENDOR_RAMDISK_TYPE_NONE indicates the value is unspecified.
+ *    - VENDOR_RAMDISK_TYPE_PLATFORM ramdisks contain platform specific bits, so
+ *      the bootloader should always load these into memory.
+ *    - VENDOR_RAMDISK_TYPE_RECOVERY ramdisks contain recovery resources, so
+ *      the bootloader should load these when booting into recovery.
+ *    - VENDOR_RAMDISK_TYPE_DLKM ramdisks contain dynamic loadable kernel
+ *      modules.
+ *
+ * Version 4 of the vendor boot image also adds a bootconfig section to the end
+ * of the image. This section contains Boot Configuration parameters known at
+ * build time. The bootloader is responsible for placing this section directly
+ * after the generic ramdisk, followed by the bootconfig trailer, before
+ * entering the kernel.
+ */
+struct boot_img_hdr_v4 : public boot_img_hdr_v3 {
+    uint32_t signature_size; /* size in bytes */
+} __attribute__((packed));
+
+struct boot_img_hdr_vnd_v4 : public boot_img_hdr_vnd_v3 {
+    uint32_t vendor_ramdisk_table_size;       /* size in bytes for the vendor ramdisk table */
+    uint32_t vendor_ramdisk_table_entry_num;  /* number of entries in the vendor ramdisk table */
+    uint32_t vendor_ramdisk_table_entry_size; /* size in bytes for a vendor ramdisk table entry */
+    uint32_t bootconfig_size; /* size in bytes for the bootconfig section */
+} __attribute__((packed));
+
+struct vendor_ramdisk_table_entry_v4 {
+    uint32_t ramdisk_size;   /* size in bytes for the ramdisk image */
+    uint32_t ramdisk_offset; /* offset to the ramdisk image in vendor ramdisk section */
+    uint32_t ramdisk_type;   /* type of the ramdisk */
+    uint8_t ramdisk_name[VENDOR_RAMDISK_NAME_SIZE]; /* asciiz ramdisk name */
+
+    // Hardware identifiers describing the board, soc or platform which this
+    // ramdisk is intended to be loaded on.
+    uint32_t board_id[VENDOR_RAMDISK_TABLE_ENTRY_BOARD_ID_SIZE];
+} __attribute__((packed));
+
 /*******************************
  * Polymorphic Universal Header
  *******************************/
@@ -310,8 +407,10 @@ protected:
         // Main header could be either AOSP or PXA
         boot_img_hdr_v2 *v2_hdr;     /* AOSP v2 header */
         boot_img_hdr_v3 *v3_hdr;     /* AOSP v3 header */
+        boot_img_hdr_v4 *v4_hdr;     /* AOSP v4 header */
         boot_img_hdr_pxa *hdr_pxa;   /* Samsung PXA header */
-        boot_img_hdr_vnd_v3 *vnd;    /* AOSP vendor v3 header */
+        boot_img_hdr_vnd_v3 *v3_vnd; /* AOSP vendor v3 header */
+        boot_img_hdr_vnd_v4 *v4_vnd; /* AOSP vendor v4 header */
         void *raw;                   /* Raw pointer */
     };
 
@@ -415,7 +514,7 @@ private:
 };
 
 #undef impl_val
-#define impl_val(name) __impl_val(name, vnd)
+#define impl_val(name) __impl_val(name, v3_vnd)
 
 struct dyn_img_vnd_v3 : public dyn_img_hdr {
     impl_cls(vnd_v3)
@@ -431,7 +530,21 @@ struct dyn_img_vnd_v3 : public dyn_img_hdr {
     size_t hdr_space() override { auto sz = page_size(); return do_align(hdr_size(), sz); }
 
     // Make API compatible
-    char *extra_cmdline() override { return &vnd->cmdline[BOOT_ARGS_SIZE]; }
+    char *extra_cmdline() override { return &v3_vnd->cmdline[BOOT_ARGS_SIZE]; }
+};
+
+#undef impl_val
+#define impl_val(name) __impl_val(name, v4_hdr)
+
+struct dyn_img_v4 : public dyn_img_v3 {
+    impl_cls(v4)
+};
+
+#undef impl_val
+#define impl_val(name) __impl_val(name, v4_vnd)
+
+struct dyn_img_vnd_v4 : public dyn_img_vnd_v3 {
+    impl_cls(vnd_v4)
 };
 
 #undef __impl_cls