qemu/hw/i386/multiboot.c
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   1/*
   2 * QEMU PC System Emulator
   3 *
   4 * Copyright (c) 2003-2004 Fabrice Bellard
   5 *
   6 * Permission is hereby granted, free of charge, to any person obtaining a copy
   7 * of this software and associated documentation files (the "Software"), to deal
   8 * in the Software without restriction, including without limitation the rights
   9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10 * copies of the Software, and to permit persons to whom the Software is
  11 * furnished to do so, subject to the following conditions:
  12 *
  13 * The above copyright notice and this permission notice shall be included in
  14 * all copies or substantial portions of the Software.
  15 *
  16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22 * THE SOFTWARE.
  23 */
  24
  25#include "qemu/osdep.h"
  26#include "qemu/option.h"
  27#include "cpu.h"
  28#include "hw/nvram/fw_cfg.h"
  29#include "multiboot.h"
  30#include "hw/loader.h"
  31#include "elf.h"
  32#include "sysemu/sysemu.h"
  33#include "qemu/error-report.h"
  34
  35/* Show multiboot debug output */
  36//#define DEBUG_MULTIBOOT
  37
  38#ifdef DEBUG_MULTIBOOT
  39#define mb_debug(a...) error_report(a)
  40#else
  41#define mb_debug(a...)
  42#endif
  43
  44#define MULTIBOOT_STRUCT_ADDR 0x9000
  45
  46#if MULTIBOOT_STRUCT_ADDR > 0xf0000
  47#error multiboot struct needs to fit in 16 bit real mode
  48#endif
  49
  50enum {
  51    /* Multiboot info */
  52    MBI_FLAGS       = 0,
  53    MBI_MEM_LOWER   = 4,
  54    MBI_MEM_UPPER   = 8,
  55    MBI_BOOT_DEVICE = 12,
  56    MBI_CMDLINE     = 16,
  57    MBI_MODS_COUNT  = 20,
  58    MBI_MODS_ADDR   = 24,
  59    MBI_MMAP_ADDR   = 48,
  60    MBI_BOOTLOADER  = 64,
  61
  62    MBI_SIZE        = 88,
  63
  64    /* Multiboot modules */
  65    MB_MOD_START    = 0,
  66    MB_MOD_END      = 4,
  67    MB_MOD_CMDLINE  = 8,
  68
  69    MB_MOD_SIZE     = 16,
  70
  71    /* Region offsets */
  72    ADDR_E820_MAP = MULTIBOOT_STRUCT_ADDR + 0,
  73    ADDR_MBI      = ADDR_E820_MAP + 0x500,
  74
  75    /* Multiboot flags */
  76    MULTIBOOT_FLAGS_MEMORY      = 1 << 0,
  77    MULTIBOOT_FLAGS_BOOT_DEVICE = 1 << 1,
  78    MULTIBOOT_FLAGS_CMDLINE     = 1 << 2,
  79    MULTIBOOT_FLAGS_MODULES     = 1 << 3,
  80    MULTIBOOT_FLAGS_MMAP        = 1 << 6,
  81    MULTIBOOT_FLAGS_BOOTLOADER  = 1 << 9,
  82};
  83
  84typedef struct {
  85    /* buffer holding kernel, cmdlines and mb_infos */
  86    void *mb_buf;
  87    /* address in target */
  88    hwaddr mb_buf_phys;
  89    /* size of mb_buf in bytes */
  90    unsigned mb_buf_size;
  91    /* offset of mb-info's in bytes */
  92    hwaddr offset_mbinfo;
  93    /* offset in buffer for cmdlines in bytes */
  94    hwaddr offset_cmdlines;
  95    /* offset in buffer for bootloader name in bytes */
  96    hwaddr offset_bootloader;
  97    /* offset of modules in bytes */
  98    hwaddr offset_mods;
  99    /* available slots for mb modules infos */
 100    int mb_mods_avail;
 101    /* currently used slots of mb modules */
 102    int mb_mods_count;
 103} MultibootState;
 104
 105const char *bootloader_name = "qemu";
 106
 107static uint32_t mb_add_cmdline(MultibootState *s, const char *cmdline)
 108{
 109    hwaddr p = s->offset_cmdlines;
 110    char *b = (char *)s->mb_buf + p;
 111
 112    memcpy(b, cmdline, strlen(cmdline) + 1);
 113    s->offset_cmdlines += strlen(b) + 1;
 114    return s->mb_buf_phys + p;
 115}
 116
 117static uint32_t mb_add_bootloader(MultibootState *s, const char *bootloader)
 118{
 119    hwaddr p = s->offset_bootloader;
 120    char *b = (char *)s->mb_buf + p;
 121
 122    memcpy(b, bootloader, strlen(bootloader) + 1);
 123    s->offset_bootloader += strlen(b) + 1;
 124    return s->mb_buf_phys + p;
 125}
 126
 127static void mb_add_mod(MultibootState *s,
 128                       hwaddr start, hwaddr end,
 129                       hwaddr cmdline_phys)
 130{
 131    char *p;
 132    assert(s->mb_mods_count < s->mb_mods_avail);
 133
 134    p = (char *)s->mb_buf + s->offset_mbinfo + MB_MOD_SIZE * s->mb_mods_count;
 135
 136    stl_p(p + MB_MOD_START,   start);
 137    stl_p(p + MB_MOD_END,     end);
 138    stl_p(p + MB_MOD_CMDLINE, cmdline_phys);
 139
 140    mb_debug("mod%02d: "TARGET_FMT_plx" - "TARGET_FMT_plx,
 141             s->mb_mods_count, start, end);
 142
 143    s->mb_mods_count++;
 144}
 145
 146int load_multiboot(X86MachineState *x86ms,
 147                   FWCfgState *fw_cfg,
 148                   FILE *f,
 149                   const char *kernel_filename,
 150                   const char *initrd_filename,
 151                   const char *kernel_cmdline,
 152                   int kernel_file_size,
 153                   uint8_t *header)
 154{
 155    bool multiboot_dma_enabled = X86_MACHINE_GET_CLASS(x86ms)->fwcfg_dma_enabled;
 156    int i, is_multiboot = 0;
 157    uint32_t flags = 0;
 158    uint32_t mh_entry_addr;
 159    uint32_t mh_load_addr;
 160    uint32_t mb_kernel_size;
 161    MultibootState mbs;
 162    uint8_t bootinfo[MBI_SIZE];
 163    uint8_t *mb_bootinfo_data;
 164    uint32_t cmdline_len;
 165    GList *mods = NULL;
 166    g_autofree char *kcmdline = NULL;
 167
 168    /* Ok, let's see if it is a multiboot image.
 169       The header is 12x32bit long, so the latest entry may be 8192 - 48. */
 170    for (i = 0; i < (8192 - 48); i += 4) {
 171        if (ldl_p(header+i) == 0x1BADB002) {
 172            uint32_t checksum = ldl_p(header+i+8);
 173            flags = ldl_p(header+i+4);
 174            checksum += flags;
 175            checksum += (uint32_t)0x1BADB002;
 176            if (!checksum) {
 177                is_multiboot = 1;
 178                break;
 179            }
 180        }
 181    }
 182
 183    if (!is_multiboot)
 184        return 0; /* no multiboot */
 185
 186    mb_debug("I believe we found a multiboot image!");
 187    memset(bootinfo, 0, sizeof(bootinfo));
 188    memset(&mbs, 0, sizeof(mbs));
 189
 190    if (flags & 0x00000004) { /* MULTIBOOT_HEADER_HAS_VBE */
 191        error_report("multiboot knows VBE. we don't");
 192    }
 193    if (!(flags & 0x00010000)) { /* MULTIBOOT_HEADER_HAS_ADDR */
 194        uint64_t elf_entry;
 195        uint64_t elf_low, elf_high;
 196        int kernel_size;
 197        fclose(f);
 198
 199        if (((struct elf64_hdr*)header)->e_machine == EM_X86_64) {
 200            error_report("Cannot load x86-64 image, give a 32bit one.");
 201            exit(1);
 202        }
 203
 204        kernel_size = load_elf(kernel_filename, NULL, NULL, NULL, &elf_entry,
 205                               &elf_low, &elf_high, NULL, 0, I386_ELF_MACHINE,
 206                               0, 0);
 207        if (kernel_size < 0) {
 208            error_report("Error while loading elf kernel");
 209            exit(1);
 210        }
 211        mh_load_addr = elf_low;
 212        mb_kernel_size = elf_high - elf_low;
 213        mh_entry_addr = elf_entry;
 214
 215        mbs.mb_buf = g_malloc(mb_kernel_size);
 216        if (rom_copy(mbs.mb_buf, mh_load_addr, mb_kernel_size) != mb_kernel_size) {
 217            error_report("Error while fetching elf kernel from rom");
 218            exit(1);
 219        }
 220
 221        mb_debug("loading multiboot-elf kernel "
 222                 "(%#x bytes) with entry %#zx",
 223                 mb_kernel_size, (size_t)mh_entry_addr);
 224    } else {
 225        /* Valid if mh_flags sets MULTIBOOT_HEADER_HAS_ADDR. */
 226        uint32_t mh_header_addr = ldl_p(header+i+12);
 227        uint32_t mh_load_end_addr = ldl_p(header+i+20);
 228        uint32_t mh_bss_end_addr = ldl_p(header+i+24);
 229
 230        mh_load_addr = ldl_p(header+i+16);
 231        if (mh_header_addr < mh_load_addr) {
 232            error_report("invalid load_addr address");
 233            exit(1);
 234        }
 235        if (mh_header_addr - mh_load_addr > i) {
 236            error_report("invalid header_addr address");
 237            exit(1);
 238        }
 239
 240        uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
 241        uint32_t mb_load_size = 0;
 242        mh_entry_addr = ldl_p(header+i+28);
 243
 244        if (mh_load_end_addr) {
 245            if (mh_load_end_addr < mh_load_addr) {
 246                error_report("invalid load_end_addr address");
 247                exit(1);
 248            }
 249            mb_load_size = mh_load_end_addr - mh_load_addr;
 250        } else {
 251            if (kernel_file_size < mb_kernel_text_offset) {
 252                error_report("invalid kernel_file_size");
 253                exit(1);
 254            }
 255            mb_load_size = kernel_file_size - mb_kernel_text_offset;
 256        }
 257        if (mb_load_size > UINT32_MAX - mh_load_addr) {
 258            error_report("kernel does not fit in address space");
 259            exit(1);
 260        }
 261        if (mh_bss_end_addr) {
 262            if (mh_bss_end_addr < (mh_load_addr + mb_load_size)) {
 263                error_report("invalid bss_end_addr address");
 264                exit(1);
 265            }
 266            mb_kernel_size = mh_bss_end_addr - mh_load_addr;
 267        } else {
 268            mb_kernel_size = mb_load_size;
 269        }
 270
 271        mb_debug("multiboot: header_addr = %#x", mh_header_addr);
 272        mb_debug("multiboot: load_addr = %#x", mh_load_addr);
 273        mb_debug("multiboot: load_end_addr = %#x", mh_load_end_addr);
 274        mb_debug("multiboot: bss_end_addr = %#x", mh_bss_end_addr);
 275        mb_debug("loading multiboot kernel (%#x bytes) at %#x",
 276                 mb_load_size, mh_load_addr);
 277
 278        mbs.mb_buf = g_malloc(mb_kernel_size);
 279        fseek(f, mb_kernel_text_offset, SEEK_SET);
 280        if (fread(mbs.mb_buf, 1, mb_load_size, f) != mb_load_size) {
 281            error_report("fread() failed");
 282            exit(1);
 283        }
 284        memset(mbs.mb_buf + mb_load_size, 0, mb_kernel_size - mb_load_size);
 285        fclose(f);
 286    }
 287
 288    mbs.mb_buf_phys = mh_load_addr;
 289
 290    mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_kernel_size);
 291    mbs.offset_mbinfo = mbs.mb_buf_size;
 292
 293    /* Calculate space for cmdlines, bootloader name, and mb_mods */
 294    cmdline_len = strlen(kernel_filename) + 1;
 295    cmdline_len += strlen(kernel_cmdline) + 1;
 296    if (initrd_filename) {
 297        const char *r = initrd_filename;
 298        cmdline_len += strlen(initrd_filename) + 1;
 299        while (*r) {
 300            char *value;
 301            r = get_opt_value(r, &value);
 302            mbs.mb_mods_avail++;
 303            mods = g_list_append(mods, value);
 304            if (*r) {
 305                r++;
 306            }
 307        }
 308    }
 309
 310    mbs.mb_buf_size += cmdline_len;
 311    mbs.mb_buf_size += MB_MOD_SIZE * mbs.mb_mods_avail;
 312    mbs.mb_buf_size += strlen(bootloader_name) + 1;
 313
 314    mbs.mb_buf_size = TARGET_PAGE_ALIGN(mbs.mb_buf_size);
 315
 316    /* enlarge mb_buf to hold cmdlines, bootloader, mb-info structs */
 317    mbs.mb_buf            = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
 318    mbs.offset_cmdlines   = mbs.offset_mbinfo + mbs.mb_mods_avail * MB_MOD_SIZE;
 319    mbs.offset_bootloader = mbs.offset_cmdlines + cmdline_len;
 320
 321    if (mods) {
 322        GList *tmpl = mods;
 323        mbs.offset_mods = mbs.mb_buf_size;
 324
 325        while (tmpl) {
 326            char *next_space;
 327            int mb_mod_length;
 328            uint32_t offs = mbs.mb_buf_size;
 329            char *one_file = tmpl->data;
 330
 331            /* if a space comes after the module filename, treat everything
 332               after that as parameters */
 333            hwaddr c = mb_add_cmdline(&mbs, one_file);
 334            next_space = strchr(one_file, ' ');
 335            if (next_space) {
 336                *next_space = '\0';
 337            }
 338            mb_debug("multiboot loading module: %s", one_file);
 339            mb_mod_length = get_image_size(one_file);
 340            if (mb_mod_length < 0) {
 341                error_report("Failed to open file '%s'", one_file);
 342                exit(1);
 343            }
 344
 345            mbs.mb_buf_size = TARGET_PAGE_ALIGN(mb_mod_length + mbs.mb_buf_size);
 346            mbs.mb_buf = g_realloc(mbs.mb_buf, mbs.mb_buf_size);
 347
 348            if (load_image_size(one_file, (unsigned char *)mbs.mb_buf + offs,
 349                                mbs.mb_buf_size - offs) < 0) {
 350                error_report("Error loading file '%s'", one_file);
 351                exit(1);
 352            }
 353            mb_add_mod(&mbs, mbs.mb_buf_phys + offs,
 354                       mbs.mb_buf_phys + offs + mb_mod_length, c);
 355
 356            mb_debug("mod_start: %p\nmod_end:   %p\n  cmdline: "TARGET_FMT_plx,
 357                     (char *)mbs.mb_buf + offs,
 358                     (char *)mbs.mb_buf + offs + mb_mod_length, c);
 359            g_free(one_file);
 360            tmpl = tmpl->next;
 361        }
 362        g_list_free(mods);
 363    }
 364
 365    /* Commandline support */
 366    kcmdline = g_strdup_printf("%s %s", kernel_filename, kernel_cmdline);
 367    stl_p(bootinfo + MBI_CMDLINE, mb_add_cmdline(&mbs, kcmdline));
 368
 369    stl_p(bootinfo + MBI_BOOTLOADER, mb_add_bootloader(&mbs, bootloader_name));
 370
 371    stl_p(bootinfo + MBI_MODS_ADDR,  mbs.mb_buf_phys + mbs.offset_mbinfo);
 372    stl_p(bootinfo + MBI_MODS_COUNT, mbs.mb_mods_count); /* mods_count */
 373
 374    /* the kernel is where we want it to be now */
 375    stl_p(bootinfo + MBI_FLAGS, MULTIBOOT_FLAGS_MEMORY
 376                                | MULTIBOOT_FLAGS_BOOT_DEVICE
 377                                | MULTIBOOT_FLAGS_CMDLINE
 378                                | MULTIBOOT_FLAGS_MODULES
 379                                | MULTIBOOT_FLAGS_MMAP
 380                                | MULTIBOOT_FLAGS_BOOTLOADER);
 381    stl_p(bootinfo + MBI_BOOT_DEVICE, 0x8000ffff); /* XXX: use the -boot switch? */
 382    stl_p(bootinfo + MBI_MMAP_ADDR,   ADDR_E820_MAP);
 383
 384    mb_debug("multiboot: entry_addr = %#x", mh_entry_addr);
 385    mb_debug("           mb_buf_phys   = "TARGET_FMT_plx, mbs.mb_buf_phys);
 386    mb_debug("           mod_start     = "TARGET_FMT_plx,
 387             mbs.mb_buf_phys + mbs.offset_mods);
 388    mb_debug("           mb_mods_count = %d", mbs.mb_mods_count);
 389
 390    /* save bootinfo off the stack */
 391    mb_bootinfo_data = g_memdup(bootinfo, sizeof(bootinfo));
 392
 393    /* Pass variables to option rom */
 394    fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ENTRY, mh_entry_addr);
 395    fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_ADDR, mh_load_addr);
 396    fw_cfg_add_i32(fw_cfg, FW_CFG_KERNEL_SIZE, mbs.mb_buf_size);
 397    fw_cfg_add_bytes(fw_cfg, FW_CFG_KERNEL_DATA,
 398                     mbs.mb_buf, mbs.mb_buf_size);
 399
 400    fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_ADDR, ADDR_MBI);
 401    fw_cfg_add_i32(fw_cfg, FW_CFG_INITRD_SIZE, sizeof(bootinfo));
 402    fw_cfg_add_bytes(fw_cfg, FW_CFG_INITRD_DATA, mb_bootinfo_data,
 403                     sizeof(bootinfo));
 404
 405    if (multiboot_dma_enabled) {
 406        option_rom[nb_option_roms].name = "multiboot_dma.bin";
 407    } else {
 408        option_rom[nb_option_roms].name = "multiboot.bin";
 409    }
 410    option_rom[nb_option_roms].bootindex = 0;
 411    nb_option_roms++;
 412
 413    return 1; /* yes, we are multiboot */
 414}
 415