/* SPDX-FileCopyrightText: 2023 Richard Masters */ /* SPDX-License-Identifier: MIT */ #include #include #include #include "multiboot1.h" #define MULTIBOOT_MAGIC 0x2BADB002 #define INITRD_MB 1152 int main() { /* Read the kernel */ printf("kexec-fiwix: starting...\n\n"); FILE *fiwix_file = fopen("/boot/fiwix", "r"); fseek(fiwix_file, 0, SEEK_END); int fiwix_len = ftell(fiwix_file); printf("kexec-fiwix: Fiwix kernel file length: %d\n", fiwix_len); puts("kexec-fiwix: Reading kernel..."); fseek(fiwix_file, 0, SEEK_SET); char * fiwix_mem = malloc(fiwix_len); int read_len = fread(fiwix_mem, fiwix_len, 1, fiwix_file); fclose(fiwix_file); if (read_len < 1) { printf("kexec-fiwix: kernel fread error: %d\n", read_len); return EXIT_FAILURE; } /* Display info from ELF header */ unsigned int e_entry = *((unsigned int *) (&fiwix_mem[0x18])); printf("ELF virtual entry point : 0x%x\n", e_entry); unsigned int e_phoff = *((unsigned int *) (&fiwix_mem[0x1C])); printf("ELF program header offset : 0x%x\n", e_phoff); unsigned int e_phnum = *((unsigned int *) (&fiwix_mem[0x2C])); e_phnum &= 0xFFFF; printf("ELF number of program headers: %d\n", e_phnum); unsigned int e_phentsize = *((unsigned int *) (&fiwix_mem[0x2A])); e_phentsize &= 0xFFFF; printf("ELF size of program headers : %d\n", e_phentsize); /* Load the kernel */ puts("kexec-fiwix: Placing kernel in memory..."); int header_num; for (header_num = 0; header_num < e_phnum; header_num++) { char * fiwix_prog_header = &fiwix_mem[e_phoff + header_num * e_phentsize]; unsigned int p_offset = *((unsigned int *) (&fiwix_prog_header[0x04])); unsigned int p_vaddr = *((unsigned int *) (&fiwix_prog_header[0x08])); unsigned int p_paddr = *((unsigned int *) (&fiwix_prog_header[0x0C])); unsigned int p_filesz = *((unsigned int *) (&fiwix_prog_header[0x10])); unsigned int p_memsz = *((unsigned int *) (&fiwix_prog_header[0x14])); if (header_num == 0) { e_entry -= (p_vaddr - p_paddr); printf("ELF physical entry point : 0x%x\n", e_entry); } printf("header %d:\n", header_num); printf(" p_offset: 0x%08x\n", p_offset); printf(" p_paddr : 0x%08x\n", p_paddr); printf(" p_filesz: 0x%08x\n", p_filesz); printf(" p_memsz : 0x%08x\n", p_memsz); memset((void *)p_paddr, 0, p_memsz + 0x10000); memcpy((void *)p_paddr, &fiwix_mem[p_offset], p_filesz); } puts("Preparing multiboot info for kernel..."); char cmdline[256]; /* Don't use a serial console if configured for bare metal */ char *bare_metal = getenv("BARE_METAL"); if (bare_metal != NULL && strcmp(bare_metal, "True") == 0) { sprintf(cmdline, "fiwix root=/dev/ram0 ramdisksize=%d initrd=sysa.ext2 kexec_proto=linux kexec_size=67000 kexec_cmdline=\"init=/init\"", INITRD_MB * 1024); } else { sprintf(cmdline, "fiwix console=/dev/ttyS0 root=/dev/ram0 ramdisksize=%d initrd=sysa.ext2 kexec_proto=linux kexec_size=67000 kexec_cmdline=\"init=/init console=ttyS0\"", INITRD_MB * 1024); } char * boot_loader_name = "kexec-fiwix"; unsigned int next_avail_mem = 0x9800; multiboot_info_t * pmultiboot_info = (multiboot_info_t *) next_avail_mem; memset(pmultiboot_info, 0, sizeof(multiboot_info_t)); pmultiboot_info->flags = MULTIBOOT_INFO_BOOT_LOADER_NAME | MULTIBOOT_INFO_MEMORY | MULTIBOOT_INFO_CMDLINE | MULTIBOOT_INFO_MODS | MULTIBOOT_INFO_MEM_MAP; next_avail_mem += sizeof(multiboot_info_t); pmultiboot_info->mem_lower = 0x0000027F; pmultiboot_info->mem_upper = 0x002FFB80; /* Set command line */ pmultiboot_info->cmdline = next_avail_mem; strcpy((char *) next_avail_mem, cmdline); next_avail_mem += (strlen(cmdline) + 1); /* Set ramdrive info */ pmultiboot_info->mods_count = 1; pmultiboot_info->mods_addr = next_avail_mem; multiboot_module_t *pmultiboot_module = (multiboot_module_t *) next_avail_mem; pmultiboot_module->mod_start = 0x1C6000; pmultiboot_module->mod_end = 0x1C6000 + (INITRD_MB * 1024 * 1024); next_avail_mem += sizeof(multiboot_module_t); pmultiboot_module->cmdline = next_avail_mem; strcpy((char *) next_avail_mem, "sysa.ext2"); next_avail_mem += (strlen("sysa.ext2") + 1); /* Set memory map info */ pmultiboot_info->mmap_addr = next_avail_mem; pmultiboot_info->mmap_length = 7 * sizeof(multiboot_memory_map_t); multiboot_memory_map_t *pmultiboot_memory_map = (multiboot_memory_map_t *) next_avail_mem; pmultiboot_memory_map->size = sizeof(multiboot_memory_map_t) - sizeof(multiboot_uint32_t); pmultiboot_memory_map->addr = 0x00000000; pmultiboot_memory_map->len = 0x0009FC00; pmultiboot_memory_map->type = MULTIBOOT_MEMORY_AVAILABLE; pmultiboot_memory_map++; pmultiboot_memory_map->size = sizeof(multiboot_memory_map_t) - sizeof(multiboot_uint32_t); pmultiboot_memory_map->addr = 0x0009FC00; pmultiboot_memory_map->len = 0x00000400; pmultiboot_memory_map->type = MULTIBOOT_MEMORY_RESERVED; pmultiboot_memory_map++; pmultiboot_memory_map->size = sizeof(multiboot_memory_map_t) - sizeof(multiboot_uint32_t); pmultiboot_memory_map->addr = 0x000F0000; pmultiboot_memory_map->len = 0x00010000; pmultiboot_memory_map->type = MULTIBOOT_MEMORY_RESERVED; pmultiboot_memory_map++; pmultiboot_memory_map->size = sizeof(multiboot_memory_map_t) - sizeof(multiboot_uint32_t); pmultiboot_memory_map->addr = 0x00100000; pmultiboot_memory_map->len = 0xBFEE0000; pmultiboot_memory_map->type = MULTIBOOT_MEMORY_AVAILABLE; pmultiboot_memory_map++; pmultiboot_memory_map->size = sizeof(multiboot_memory_map_t) - sizeof(multiboot_uint32_t); pmultiboot_memory_map->addr = 0XBFFE0000; pmultiboot_memory_map->len = 0x00020000; pmultiboot_memory_map->type = MULTIBOOT_MEMORY_RESERVED; pmultiboot_memory_map++; pmultiboot_memory_map->size = sizeof(multiboot_memory_map_t) - sizeof(multiboot_uint32_t); pmultiboot_memory_map->addr = 0XFEFFC000; pmultiboot_memory_map->len = 0x00004000; pmultiboot_memory_map->type = MULTIBOOT_MEMORY_RESERVED; pmultiboot_memory_map++; pmultiboot_memory_map->size = sizeof(multiboot_memory_map_t) - sizeof(multiboot_uint32_t); pmultiboot_memory_map->addr = 0XFFFC0000; pmultiboot_memory_map->len = 0x00040000; pmultiboot_memory_map->type = MULTIBOOT_MEMORY_RESERVED; pmultiboot_memory_map++; next_avail_mem += pmultiboot_info->mmap_length; /* Set boot loader name */ pmultiboot_info->boot_loader_name = next_avail_mem; strcpy((char *) next_avail_mem, boot_loader_name); /* next_avail_mem += (strlen(boot_loader_name) + 1); */ /* Jump to kernel entry point */ unsigned int magic = MULTIBOOT_BOOTLOADER_MAGIC; unsigned int dummy = 0; unsigned int multiboot_info_num = (unsigned int) pmultiboot_info; int filenum; unsigned int filename_addr; for (filenum = 4, filename_addr = 0x201000; filenum <= 14335; filenum++, filename_addr += 1024) { if (!strcmp((char *) filename_addr, "/boot/sysa.ext2")) { printf("Found image at filenum %d\n", filenum); break; } } unsigned int initrd_src = *((unsigned int *) (0x01000000 + (16 * filenum) + 4)); unsigned int initrd_len = *((unsigned int *) (0x01000000 + (16 * filenum) + 8)); printf("initrd_src: 0x%08x\n", initrd_src); printf("initrd_len: 0x%08x\n", initrd_len); printf("Preparing trampoline...\n"); /* The ramdrive needs to be written to a location that would overwrite this program. * Therfore, the code that copies the ram drive and jumps to the kernel needs to be * run from a safe location. So, we put that code into an array variable and * copy the code (called a "trampoline") to a safe location and then jump to it. * The 0x00000000 values below are place holders which are set below */ char trampoline[] = { 0xBE, 0x00, 0x00, 0x00, 0x00, /* mov esi, 0x00000000 */ 0xBF, 0x00, 0x00, 0x00, 0x00, /* mov edi, 0x00000000 */ 0xB9, 0x00, 0x00, 0x00, 0x00, /* mov ecx, 0x00000000 */ 0xFC, /* cld */ 0xF3, 0xA4, /* rep movsb */ 0xB8, 0x00, 0x00, 0x00, 0x00, /* mov eax, 0x00000000 */ 0xBB, 0x00, 0x00, 0x00, 0x00, /* mov ebx, 0x00000000 */ 0xEA, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00 /* jmp far 0x0008:0x00000000 */ }; /* Set place holder values */ *((unsigned int *) &trampoline[1]) = initrd_src; *((unsigned int *) &trampoline[6]) = 0x001C6000; *((unsigned int *) &trampoline[11]) = INITRD_MB * 1024 * 1024; *((unsigned int *) &trampoline[19]) = magic; *((unsigned int *) &trampoline[24]) = multiboot_info_num; *((unsigned int *) &trampoline[29]) = e_entry; memcpy((void *)0x4000, trampoline, sizeof(trampoline)); printf("kexec-fiwix: jumping to trampoline...\n"); __asm__ __volatile__ ( "ljmp $0x8, $0x00004000\n\t" ); }