/* ----------------------------------------------------------------------- * * * Copyright 2007-2008 H. Peter Anvin - All Rights Reserved * * Permission is hereby granted, free of charge, to any person * obtaining a copy of this software and associated documentation * files (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, * copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom * the Software is furnished to do so, subject to the following * conditions: * * The above copyright notice and this permission notice shall * be included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. * * ----------------------------------------------------------------------- */ /* * load_linux.c * * Load a Linux kernel (Image/zImage/bzImage). */ #include #include #include #include #include #include #ifndef DEBUG # define DEBUG 0 #endif #if DEBUG # include # define dprintf printf #else # define dprintf(f, ...) ((void)0) #endif struct linux_header { uint8_t boot_sector_1[0x0020]; uint16_t old_cmd_line_magic; uint16_t old_cmd_line_offset; uint8_t boot_sector_2[0x01f1-0x0024]; uint8_t setup_sects; uint16_t root_flags; uint32_t syssize; uint16_t ram_size; uint16_t vid_mode; uint16_t root_dev; uint16_t boot_flag; uint16_t jump; uint32_t header; uint16_t version; uint32_t realmode_swtch; uint16_t start_sys; uint16_t kernel_version; uint8_t type_of_loader; uint8_t loadflags; uint16_t setup_move_size; uint32_t code32_start; uint32_t ramdisk_image; uint32_t ramdisk_size; uint32_t bootsect_kludge; uint16_t heap_end_ptr; uint16_t pad1; uint32_t cmd_line_ptr; uint32_t initrd_addr_max; uint32_t kernel_alignment; uint8_t relocatable_kernel; uint8_t pad2[3]; uint32_t cmdline_max_len; } __packed; #define BOOT_MAGIC 0xAA55 #define LINUX_MAGIC ('H' + ('d' << 8) + ('r' << 16) + ('S' << 24)) #define OLD_CMDLINE_MAGIC 0xA33F /* loadflags */ #define LOAD_HIGH 0x01 #define CAN_USE_HEAP 0x80 /* Get the combined size of the initramfs */ static addr_t initramfs_size(struct initramfs *initramfs) { struct initramfs *ip; addr_t size = 0; if (!initramfs) return 0; for (ip = initramfs->next; ip->len; ip = ip->next) { size = (size+ip->align-1) & ~(ip->align-1); /* Alignment */ size += ip->len; } return size; } /* Create the appropriate mappings for the initramfs */ static int map_initramfs(struct syslinux_movelist **fraglist, struct syslinux_memmap **mmap, struct initramfs *initramfs, addr_t addr) { struct initramfs *ip; addr_t next_addr, len, pad; for (ip = initramfs->next; ip->len; ip = ip->next) { len = ip->len; next_addr = addr+len; /* If this isn't the last entry, extend the zero-pad region to enforce the alignment of the next chunk. */ if (ip->next->len) { pad = -next_addr & (ip->next->align-1); len += pad; next_addr += pad; } if (ip->data_len) { if (syslinux_add_movelist(fraglist, addr, (addr_t)ip->data, len)) return -1; } if (len > ip->data_len) { if (syslinux_add_memmap(mmap, addr+ip->data_len, len-ip->data_len, SMT_ZERO)) return -1; } addr = next_addr; } return 0; } int syslinux_boot_linux(void *kernel_buf, size_t kernel_size, struct initramfs *initramfs, char *cmdline, uint16_t video_mode, uint32_t memlimit) { struct linux_header hdr, *whdr; size_t real_mode_size, prot_mode_size; addr_t real_mode_base, prot_mode_base; addr_t irf_size; size_t cmdline_size, cmdline_offset; struct syslinux_rm_regs regs; struct syslinux_movelist *fraglist = NULL; struct syslinux_memmap *mmap = NULL; struct syslinux_memmap *amap = NULL; cmdline_size = strlen(cmdline)+1; if (kernel_size < 2*512) goto bail; /* Copy the header into private storage */ /* Use whdr to modify the actual kernel header */ memcpy(&hdr, kernel_buf, sizeof hdr); whdr = (struct linux_header *)kernel_buf; if (hdr.boot_flag != BOOT_MAGIC) goto bail; if (hdr.header != LINUX_MAGIC) { hdr.version = 0x0100; /* Very old kernel */ hdr.loadflags = 0; } whdr->vid_mode = video_mode; if (!hdr.setup_sects) hdr.setup_sects = 4; if (hdr.version < 0x0203) hdr.initrd_addr_max = 0x37ffffff; if (!memlimit || memlimit-1 > hdr.initrd_addr_max) memlimit = hdr.initrd_addr_max+1; /* Zero for no limit */ if (hdr.version < 0x0206) hdr.cmdline_max_len = 256; if (cmdline_size > hdr.cmdline_max_len) { cmdline_size = hdr.cmdline_max_len; cmdline[cmdline_size-1] = '\0'; } if (hdr.version < 0x0202 || !(hdr.loadflags & 0x01)) cmdline_offset = (0x9ff0 - cmdline_size) & ~15; else cmdline_offset = 0x10000; real_mode_size = (hdr.setup_sects+1) << 9; real_mode_base = (hdr.loadflags & LOAD_HIGH) ? 0x10000 : 0x90000; prot_mode_base = (hdr.loadflags & LOAD_HIGH) ? 0x100000 : 0x10000; prot_mode_size = kernel_size - real_mode_size; if (!(hdr.loadflags & LOAD_HIGH) && prot_mode_size > 512*1024) goto bail; /* Kernel cannot be loaded low */ if (initramfs && hdr.version < 0x0200) goto bail; /* initrd/initramfs not supported */ if (hdr.version >= 0x0200) { whdr->type_of_loader = 0x30; /* SYSLINUX unknown module */ if (hdr.version >= 0x0201) { whdr->heap_end_ptr = cmdline_offset - 0x0200; whdr->loadflags |= CAN_USE_HEAP; } if (hdr.version >= 0x0202) { whdr->cmd_line_ptr = real_mode_base+cmdline_offset; } else { whdr->old_cmd_line_magic = OLD_CMDLINE_MAGIC; whdr->old_cmd_line_offset = cmdline_offset; /* Be paranoid and round up to a multiple of 16 */ whdr->setup_move_size = (cmdline_offset+cmdline_size+15) & ~15; } } /* Get the memory map */ mmap = syslinux_memory_map(); /* Memory map for shuffle_boot */ amap = syslinux_dup_memmap(mmap); /* Keep track of available memory */ if (!mmap || !amap) goto bail; #if DEBUG dprintf("Initial memory map:\n"); syslinux_dump_memmap(stdout, mmap); #endif /* If the user has specified a memory limit, mark that as unavailable. Question: should we mark this off-limit in the mmap as well (meaning it's unavailable to the boot loader, which probably has already touched some of it), or just in the amap? */ if (memlimit) if (syslinux_add_memmap(&amap, memlimit, -memlimit, SMT_RESERVED)) goto bail; /* Place the kernel in memory */ /* Real mode code */ if (syslinux_add_movelist(&fraglist, real_mode_base, (addr_t)kernel_buf, real_mode_size)) goto bail; if (syslinux_add_memmap(&amap, real_mode_base, cmdline_offset+cmdline_size, SMT_ALLOC)) goto bail; /* Zero region between real mode code and cmdline */ if (syslinux_add_memmap(&mmap, real_mode_base+real_mode_size, cmdline_offset-real_mode_size, SMT_ZERO)) goto bail; /* Command line */ if (syslinux_add_movelist(&fraglist, real_mode_base+cmdline_offset, (addr_t)cmdline, cmdline_size)) goto bail; /* Protected-mode code */ if (syslinux_add_movelist(&fraglist, prot_mode_base, (addr_t)kernel_buf + real_mode_size, prot_mode_size)) goto bail; if (syslinux_add_memmap(&amap, prot_mode_base, prot_mode_size, SMT_ALLOC)) goto bail; /* Figure out the size of the initramfs, and where to put it. We should put it at the highest possible address which is <= hdr.initrd_addr_max, which fits the entire initramfs. */ irf_size = initramfs_size(initramfs); /* Handles initramfs == NULL */ if (irf_size) { addr_t best_addr = 0; struct syslinux_memmap *ml; const addr_t align_mask = INITRAMFS_MAX_ALIGN-1; if (irf_size) { for (ml = amap; ml->type != SMT_END; ml = ml->next) { addr_t adj_start = (ml->start+align_mask) & ~align_mask; if (ml->type == SMT_FREE && ml->next->start - adj_start >= irf_size) best_addr = (ml->next->start - irf_size) & ~align_mask; } if (!best_addr) goto bail; /* Insufficient memory for initramfs */ whdr->ramdisk_image = best_addr; whdr->ramdisk_size = irf_size; if (syslinux_add_memmap(&amap, best_addr, irf_size, SMT_ALLOC)) goto bail; if (map_initramfs(&fraglist, &mmap, initramfs, best_addr)) goto bail; } } /* Set up the registers on entry */ memset(®s, 0, sizeof regs); regs.es = regs.ds = regs.ss = regs.fs = regs.gs = real_mode_base >> 4; regs.cs = (real_mode_base >> 4)+0x20; /* regs.ip = 0; */ regs.esp.w[0] = cmdline_offset; #if DEBUG dprintf("Final memory map:\n"); syslinux_dump_memmap(stdout, mmap); dprintf("Final available map:\n"); syslinux_dump_memmap(stdout, amap); dprintf("Initial movelist:\n"); syslinux_dump_movelist(stdout, fraglist); #endif syslinux_shuffle_boot_rm(fraglist, mmap, 0, ®s); bail: syslinux_free_movelist(fraglist); syslinux_free_memmap(mmap); syslinux_free_memmap(amap); return -1; }