/* * (C) Copyright 2002 * Daniel Engström, Omicron Ceti AB, daniel@omicron.se * * See file CREDITS for list of people who contributed to this * project. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation; either version 2 of * the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, * MA 02111-1307 USA */ /* * Linux i386 zImage and bzImage loading * * based on the procdure described in * linux/Documentation/i386/boot.txt */ #include #include #include #include #include #include /* * Memory lay-out: * * relative to setup_base (which is 0x90000 currently) * * 0x0000-0x7FFF Real mode kernel * 0x8000-0x8FFF Stack and heap * 0x9000-0x90FF Kernel command line */ #define DEFAULT_SETUP_BASE 0x90000 #define COMMAND_LINE_OFFSET 0x9000 #define HEAP_END_OFFSET 0x8e00 #define COMMAND_LINE_SIZE 2048 static void build_command_line(char *command_line, int auto_boot) { char *env_command_line; command_line[0] = '\0'; env_command_line = getenv("bootargs"); /* set console= argument if we use a serial console */ if (NULL == strstr(env_command_line, "console=")) { if (0==strcmp(getenv("stdout"), "serial")) { /* We seem to use serial console */ sprintf(command_line, "console=ttyS0,%s ", getenv("baudrate")); } } if (auto_boot) { strcat(command_line, "auto "); } if (NULL != env_command_line) { strcat(command_line, env_command_line); } printf("Kernel command line: \"%s\"\n", command_line); } void *load_zimage(char *image, unsigned long kernel_size, unsigned long initrd_addr, unsigned long initrd_size, int auto_boot) { void *setup_base; int setup_size; int bootproto; int big_image; void *load_address; setup_base = (void*)DEFAULT_SETUP_BASE; /* base address for real-mode segment */ if (KERNEL_MAGIC != *(u16*)(image + BOOT_FLAG_OFF)) { printf("Error: Invalid kernel magic (found 0x%04x, expected 0xaa55)\n", *(u16*)(image + BOOT_FLAG_OFF)); return 0; } /* determine boot protocol version */ if (KERNEL_V2_MAGIC == *(u32*)(image+HEADER_OFF)) { bootproto = *(u16*)(image+VERSION_OFF); } else { /* Very old kernel */ bootproto = 0x0100; } /* determine size of setup */ if (0 == *(u8*)(image + SETUP_SECTS_OFF)) { setup_size = 5 * 512; } else { setup_size = (*(u8*)(image + SETUP_SECTS_OFF) + 1) * 512; } if (setup_size > SETUP_MAX_SIZE) { printf("Error: Setup is too large (%d bytes)\n", setup_size); } /* Determine image type */ big_image = (bootproto >= 0x0200) && (*(u8*)(image + LOADFLAGS_OFF) & BIG_KERNEL_FLAG); /* Derermine load address */ load_address = (void*)(big_image ? BZIMAGE_LOAD_ADDR:ZIMAGE_LOAD_ADDR); /* load setup */ memmove(setup_base, image, setup_size); printf("Using boot protocol version %x.%02x\n", (bootproto & 0xff00) >> 8, bootproto & 0xff); if (bootproto == 0x0100) { *(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC; *(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET; /* A very old kernel MUST have its real-mode code * loaded at 0x90000 */ if ((u32)setup_base != 0x90000) { /* Copy the real-mode kernel */ memmove((void*)0x90000, setup_base, setup_size); /* Copy the command line */ memmove((void*)0x99000, setup_base+COMMAND_LINE_OFFSET, COMMAND_LINE_SIZE); setup_base = (void*)0x90000; /* Relocated */ } /* It is recommended to clear memory up to the 32K mark */ memset((void*)0x90000 + setup_size, 0, SETUP_MAX_SIZE-setup_size); } if (bootproto >= 0x0200) { *(u8*)(setup_base + TYPE_OF_LOADER_OFF) = 0xff; printf("Linux kernel version %s\n", (char*)(setup_base + SETUP_START_OFFSET + *(u16*)(setup_base + START_SYS_OFF + 2))); if (initrd_addr) { printf("Initial RAM disk at linear address 0x%08lx, size %ld bytes\n", initrd_addr, initrd_size); *(u32*)(setup_base + RAMDISK_IMAGE_OFF) = initrd_addr; *(u32*)(setup_base + RAMDISK_SIZE_OFF)=initrd_size; } } if (bootproto >= 0x0201) { *(u16*)(setup_base + HEAP_END_PTR_OFF) = HEAP_END_OFFSET; /* CAN_USE_HEAP */ *(u8*)(setup_base + LOADFLAGS_OFF) = *(u8*)(setup_base + LOADFLAGS_OFF) | HEAP_FLAG; } if (bootproto >= 0x0202) { *(u32*)(setup_base + CMD_LINE_PTR_OFF) = (u32)setup_base + COMMAND_LINE_OFFSET; } else if (bootproto >= 0x0200) { *(u16*)(setup_base + CMD_LINE_MAGIC_OFF) = COMMAND_LINE_MAGIC; *(u16*)(setup_base + CMD_LINE_OFFSET_OFF) = COMMAND_LINE_OFFSET; *(u16*)(setup_base + SETUP_MOVE_SIZE_OFF) = 0x9100; } if (big_image) { if ((kernel_size - setup_size) > BZIMAGE_MAX_SIZE) { printf("Error: bzImage kernel too big! (size: %ld, max: %d)\n", kernel_size - setup_size, BZIMAGE_MAX_SIZE); return 0; } } else if ((kernel_size - setup_size) > ZIMAGE_MAX_SIZE) { printf("Error: zImage kernel too big! (size: %ld, max: %d)\n", kernel_size - setup_size, ZIMAGE_MAX_SIZE); return 0; } /* build command line at COMMAND_LINE_OFFSET */ build_command_line(setup_base + COMMAND_LINE_OFFSET, auto_boot); printf("Loading %czImage at address 0x%08x (%ld bytes)\n", big_image ? 'b' : ' ', (u32)load_address, kernel_size - setup_size); memmove(load_address, image + setup_size, kernel_size - setup_size); /* ready for booting */ return setup_base; } void boot_zimage(void *setup_base) { struct pt_regs regs; memset(®s, 0, sizeof(struct pt_regs)); regs.xds = (u32)setup_base >> 4; regs.xss = 0x9000; regs.esp = 0x9000; regs.eflags = 0; enter_realmode(((u32)setup_base+SETUP_START_OFFSET)>>4, 0, ®s, ®s); } image_header_t *fake_zimage_header(image_header_t *hdr, void *ptr, int size) { /* There is no way to know the size of a zImage ... * * so we assume that 2MB will be enough for now */ #define ZIMAGE_SIZE 0x200000 /* load a 1MB, the loaded will have to be moved to its final * position again later... */ #define ZIMAGE_LOAD 0x100000 ulong checksum; if (KERNEL_MAGIC != *(u16*)(ptr + BOOT_FLAG_OFF)) { /* not a zImage or bzImage */ return NULL; } if (-1 == size) { size = ZIMAGE_SIZE; } #if 0 checksum = crc32 (0, ptr, size); #else checksum = 0; #endif memset(hdr, 0, sizeof(image_header_t)); /* Build new header */ hdr->ih_magic = htonl(IH_MAGIC); hdr->ih_time = 0; hdr->ih_size = htonl(size); hdr->ih_load = htonl(ZIMAGE_LOAD); hdr->ih_ep = 0; hdr->ih_dcrc = htonl(checksum); hdr->ih_os = IH_OS_LINUX; hdr->ih_arch = IH_CPU_I386; hdr->ih_type = IH_TYPE_KERNEL; hdr->ih_comp = IH_COMP_NONE; strncpy((char *)hdr->ih_name, "(none)", IH_NMLEN); checksum = crc32(0,(const char *)hdr,sizeof(image_header_t)); hdr->ih_hcrc = htonl(checksum); return hdr; }