uboot解析uImage的kernel信息 ============================ kernel信息的存放位置 --------------------- kernel信息主要包括两方面内容: - kernel的镜像信息(包括其加载地址)：放在bootm_headers_t images->image_info_t os中 - kernel的入口地址:放在bootm_headers_t images->ulong ep中 详细可以参考 ``include/image.h`` :: typedef struct bootm_headers { /* * Legacy os image header, if it is a multi component image * then boot_get_ramdisk() and get_fdt() will attempt to get * data from second and third component accordingly. */ image_header_t *legacy_hdr_os; /* image header pointer */ image_header_t legacy_hdr_os_copy; /* header copy */ ulong legacy_hdr_valid; #if IMAGE_ENABLE_FIT const char *fit_uname_cfg; /* configuration node unit name */ void *fit_hdr_os; /* os FIT image header */ const char *fit_uname_os; /* os subimage node unit name */ int fit_noffset_os; /* os subimage node offset */ void *fit_hdr_rd; /* init ramdisk FIT image header */ const char *fit_uname_rd; /* init ramdisk subimage node unit name */ int fit_noffset_rd; /* init ramdisk subimage node offset */ void *fit_hdr_fdt; /* FDT blob FIT image header */ const char *fit_uname_fdt; /* FDT blob subimage node unit name */ int fit_noffset_fdt;/* FDT blob subimage node offset */ void *fit_hdr_setup; /* x86 setup FIT image header */ const char *fit_uname_setup; /* x86 setup subimage node name */ int fit_noffset_setup;/* x86 setup subimage node offset */ #endif #ifndef USE_HOSTCC image_info_t os; /* os image info */ ulong ep; /* entry point of OS */ ulong rd_start, rd_end;/* ramdisk start/end */ char *ft_addr; /* flat dev tree address */ ulong ft_len; /* length of flat device tree */ ulong initrd_start; ulong initrd_end; ulong cmdline_start; ulong cmdline_end; bd_t *kbd; #endif int verify; /* env_get("verify")[0] != 'n' */ #define BOOTM_STATE_START (0x00000001) #define BOOTM_STATE_FINDOS (0x00000002) #define BOOTM_STATE_FINDOTHER (0x00000004) #define BOOTM_STATE_LOADOS (0x00000008) #define BOOTM_STATE_RAMDISK (0x00000010) #define BOOTM_STATE_FDT (0x00000020) #define BOOTM_STATE_OS_CMDLINE (0x00000040) #define BOOTM_STATE_OS_BD_T (0x00000080) #define BOOTM_STATE_OS_PREP (0x00000100) #define BOOTM_STATE_OS_FAKE_GO (0x00000200) /* 'Almost' run the OS */ #define BOOTM_STATE_OS_GO (0x00000400) int state; #ifdef CONFIG_LMB struct lmb lmb; /* for memory mgmt */ #endif } bootm_headers_t; extern bootm_headers_t images; image_info_t的详细解释如下 :: typedef struct image_info { ulong start, end; /* start/end of blob */ //包括附加节点信息之内的整个kernel节点的起始地址和结束地址 ulong image_start, image_len; /* start of image within blob, len of image */ //kernel镜像的起始地址，镜像长度 ulong load; /* load addr for the image */ //镜像的加载地址 uint8_t comp, type, os; /* compression, type of image, os type */ //镜像的压缩格式，镜像类型，操作系统类型 uint8_t arch; /* CPU architecture */ //CPU体系结构 } image_info_t; - image_header数据结构如下 :: /* * Legacy format image header, * all data in network byte order (aka natural aka bigendian). */ typedef struct image_header { __be32 ih_magic; /* Image Header Magic Number */ __be32 ih_hcrc; /* Image Header CRC Checksum */ __be32 ih_time; /* Image Creation Timestamp */ __be32 ih_size; /* Image Data Size */ __be32 ih_load; /* Data Load Address */ __be32 ih_ep; /* Entry Point Address */ __be32 ih_dcrc; /* Image Data CRC Checksum */ uint8_t ih_os; /* Operating System */ uint8_t ih_arch; /* CPU architecture */ uint8_t ih_type; /* Image Type */ uint8_t ih_comp; /* Compression Type */ uint8_t ih_name[IH_NMLEN]; /* Image Name */ } image_header_t; 解析uImage的时候主要目的就是填充image_info_t os和ulong ep 解析完成之后的示例如下 .. image:: res/images_header.png legacy-uImage中kernel信息的解析代码流程 ---------------------------------------- 从bootm_find_os入口开始说明，代码位于 ``common/bootm.c`` 中 :: static int bootm_find_os(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { //uImage地址对应传进来的参数argv[0] const void *os_hdr; bool ep_found = false; int ret; /* get kernel image header, start address and length */ os_hdr = boot_get_kernel(cmdtp, flag, argc, argv, &images, &images.os.image_start, &images.os.image_len); //在boot_get_kernel中会设置images.os.image_start和images.os.image_len值 if (images.os.image_len == 0) { puts("ERROR: can't get kernel image!\n"); return 1; } /* get image parameters */ switch (genimg_get_format(os_hdr)) { #if defined(CONFIG_IMAGE_FORMAT_LEGACY) case IMAGE_FORMAT_LEGACY: images.os.type = image_get_type(os_hdr); //从头部中获取各参数值 images.os.comp = image_get_comp(os_hdr); images.os.os = image_get_os(os_hdr); images.os.end = image_get_image_end(os_hdr); images.os.load = image_get_load(os_hdr); images.os.arch = image_get_arch(os_hdr); break; #endif #if IMAGE_ENABLE_FIT case IMAGE_FORMAT_FIT: if (fit_image_get_type(images.fit_hdr_os, images.fit_noffset_os, &images.os.type)) { puts("Can't get image type!\n"); bootstage_error(BOOTSTAGE_ID_FIT_TYPE); return 1; } if (fit_image_get_comp(images.fit_hdr_os, images.fit_noffset_os, &images.os.comp)) { puts("Can't get image compression!\n"); bootstage_error(BOOTSTAGE_ID_FIT_COMPRESSION); return 1; } if (fit_image_get_os(images.fit_hdr_os, images.fit_noffset_os, &images.os.os)) { puts("Can't get image OS!\n"); bootstage_error(BOOTSTAGE_ID_FIT_OS); return 1; } if (fit_image_get_arch(images.fit_hdr_os, images.fit_noffset_os, &images.os.arch)) { puts("Can't get image ARCH!\n"); return 1; } images.os.end = fit_get_end(images.fit_hdr_os); if (fit_image_get_load(images.fit_hdr_os, images.fit_noffset_os, &images.os.load)) { puts("Can't get image load address!\n"); bootstage_error(BOOTSTAGE_ID_FIT_LOADADDR); return 1; } break; #endif #ifdef CONFIG_ANDROID_BOOT_IMAGE case IMAGE_FORMAT_ANDROID: images.os.type = IH_TYPE_KERNEL; images.os.comp = IH_COMP_GZIP; images.os.os = IH_OS_LINUX; images.os.end = android_image_get_end(os_hdr); images.os.load = android_image_get_kload(os_hdr); images.ep = images.os.load; ep_found = true; break; #endif default: puts("ERROR: unknown image format type!\n"); return 1; } /* If we have a valid setup.bin, we will use that for entry (x86) */ if (images.os.arch == IH_ARCH_I386 || images.os.arch == IH_ARCH_X86_64) { ulong len; ret = boot_get_setup(&images, IH_ARCH_I386, &images.ep, &len); if (ret < 0 && ret != -ENOENT) { puts("Could not find a valid setup.bin for x86\n"); return 1; } /* Kernel entry point is the setup.bin */ } else if (images.legacy_hdr_valid) { images.ep = image_get_ep(&images.legacy_hdr_os_copy); #if IMAGE_ENABLE_FIT } else if (images.fit_uname_os) { int ret; ret = fit_image_get_entry(images.fit_hdr_os, images.fit_noffset_os, &images.ep); if (ret) { puts("Can't get entry point property!\n"); return 1; } #endif } else if (!ep_found) { puts("Could not find kernel entry point!\n"); return 1; } if (images.os.type == IH_TYPE_KERNEL_NOLOAD) { if (CONFIG_IS_ENABLED(CMD_BOOTI) && images.os.arch == IH_ARCH_ARM64) { ulong image_addr; ulong image_size; ret = booti_setup(images.os.image_start, &image_addr, &image_size, true); if (ret != 0) return 1; images.os.type = IH_TYPE_KERNEL; images.os.load = image_addr; images.ep = image_addr; } else { images.os.load = images.os.image_start; images.ep += images.os.image_start; } } images.os.start = map_to_sysmem(os_hdr); return 0; } 通过上述代码就完成了bootm_header_t images中的image_info_t os和ulong ep成员的实现,这里的核心代码是boot_get_kernel会实现uImage类型的判断以及头部的设置 - boot_get_kernel :: /** * boot_get_kernel - find kernel image * @os_data: pointer to a ulong variable, will hold os data start address * @os_len: pointer to a ulong variable, will hold os data length * * boot_get_kernel() tries to find a kernel image, verifies its integrity * and locates kernel data. * * returns: * pointer to image header if valid image was found, plus kernel start * address and length, otherwise NULL */ static const void *boot_get_kernel(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[], bootm_headers_t *images, ulong *os_data, ulong *os_len) { #if defined(CONFIG_IMAGE_FORMAT_LEGACY) image_header_t *hdr; #endif ulong img_addr; const void *buf; const char *fit_uname_config = NULL; const char *fit_uname_kernel = NULL; #if IMAGE_ENABLE_FIT int os_noffset; #endif //因为传进来的kernel地址argv[0]是一个字符串类型，所以这里需要将其转换为长整型 img_addr = genimg_get_kernel_addr_fit(argc < 1 ? NULL : argv[0], &fit_uname_config, &fit_uname_kernel); bootstage_mark(BOOTSTAGE_ID_CHECK_MAGIC); /* check image type, for FIT images get FIT kernel node */ *os_data = *os_len = 0; buf = map_sysmem(img_addr, 0); //映射到物理地址，因为在uboot中MMU一般是没有打开的，所以这个值不会变化 switch (genimg_get_format(buf)) { //这里根据幻数判断uImage类型 #if defined(CONFIG_IMAGE_FORMAT_LEGACY) case IMAGE_FORMAT_LEGACY: printf("## Booting kernel from Legacy Image at %08lx ...\n", img_addr); hdr = image_get_kernel(img_addr, images->verify); if (!hdr) return NULL; bootstage_mark(BOOTSTAGE_ID_CHECK_IMAGETYPE); /* get os_data and os_len */ switch (image_get_type(hdr)) { case IH_TYPE_KERNEL: case IH_TYPE_KERNEL_NOLOAD: *os_data = image_get_data(hdr); //设置镜像地址及长度 *os_len = image_get_data_size(hdr); break; case IH_TYPE_MULTI: image_multi_getimg(hdr, 0, os_data, os_len); break; case IH_TYPE_STANDALONE: *os_data = image_get_data(hdr); *os_len = image_get_data_size(hdr); break; default: printf("Wrong Image Type for %s command\n", cmdtp->name); bootstage_error(BOOTSTAGE_ID_CHECK_IMAGETYPE); return NULL; } /* * copy image header to allow for image overwrites during * kernel decompression. */ memmove(&images->legacy_hdr_os_copy, hdr, sizeof(image_header_t)); /* save pointer to image header */ images->legacy_hdr_os = hdr; images->legacy_hdr_valid = 1; bootstage_mark(BOOTSTAGE_ID_DECOMP_IMAGE); break; #endif #if IMAGE_ENABLE_FIT case IMAGE_FORMAT_FIT: os_noffset = fit_image_load(images, img_addr, &fit_uname_kernel, &fit_uname_config, IH_ARCH_DEFAULT, IH_TYPE_KERNEL, BOOTSTAGE_ID_FIT_KERNEL_START, FIT_LOAD_IGNORED, os_data, os_len); if (os_noffset < 0) return NULL; images->fit_hdr_os = map_sysmem(img_addr, 0); images->fit_uname_os = fit_uname_kernel; images->fit_uname_cfg = fit_uname_config; images->fit_noffset_os = os_noffset; break; #endif #ifdef CONFIG_ANDROID_BOOT_IMAGE case IMAGE_FORMAT_ANDROID: #if !(UBOOT_LOG_OPTIMIZE) printf("## Booting Android Image at 0x%08lx ...\n", img_addr); #endif if (android_image_get_kernel(buf, images->verify, os_data, os_len)) return NULL; break; #endif default: printf("Wrong Image Format for %s command\n", cmdtp->name); bootstage_error(BOOTSTAGE_ID_FIT_KERNEL_INFO); return NULL; } debug(" kernel data at 0x%08lx, len = 0x%08lx (%ld)\n", *os_data, *os_len, *os_len); return buf; } FIT-uImage中kernel信息的解析 ----------------------------- FIT-uImage信息的解析可以参考上述代码的实现