gwj / at91sam9263 · Commits

Commit 4fc9af53d88c0a2a810704a06cb39a7182982e4e

Authored by aliguori
1 parent 6223246a

Use an option rom instead of boot sector for -kernel 

Generate an option rom instead of using a hijacked boot sector for kernel
booting.  This just requires adding a small option ROM header and a few more
instructions to the boot sector to take over the int19 vector and run our
boot code.

A disk is no longer needed when using -kernel on x86.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5650 c046a42c-6fe2-441c-8c8c-71466251a162
Inline Side-by-side
Showing 4 changed files with 50 additions and 58 deletions
... ... @@ -527,14 +527,6 @@ int bdrv_read(BlockDriverState *bs, int64_t sector_num,
527 527 if (!drv)
528 528 return -ENOMEDIUM;
529 529  
530   - if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
531   - memcpy(buf, bs->boot_sector_data, 512);
532   - sector_num++;
533   - nb_sectors--;
534   - buf += 512;
535   - if (nb_sectors == 0)
536   - return 0;
537   - }
538 530 if (drv->bdrv_pread) {
539 531 int ret, len;
540 532 len = nb_sectors * 512;
... ... @@ -567,9 +559,6 @@ int bdrv_write(BlockDriverState *bs, int64_t sector_num,
567 559 return -ENOMEDIUM;
568 560 if (bs->read_only)
569 561 return -EACCES;
570   - if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
571   - memcpy(bs->boot_sector_data, buf, 512);
572   - }
573 562 if (drv->bdrv_pwrite) {
574 563 int ret, len;
575 564 len = nb_sectors * 512;
... ... @@ -750,16 +739,6 @@ void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
750 739 *nb_sectors_ptr = length;
751 740 }
752 741  
753   -/* force a given boot sector. */
754   -void bdrv_set_boot_sector(BlockDriverState *bs, const uint8_t *data, int size)
755   -{
756   - bs->boot_sector_enabled = 1;
757   - if (size > 512)
758   - size = 512;
759   - memcpy(bs->boot_sector_data, data, size);
760   - memset(bs->boot_sector_data + size, 0, 512 - size);
761   -}
762   -
763 742 void bdrv_set_geometry_hint(BlockDriverState *bs,
764 743 int cyls, int heads, int secs)
765 744 {
... ... @@ -1155,14 +1134,6 @@ BlockDriverAIOCB *bdrv_aio_read(BlockDriverState *bs, int64_t sector_num,
1155 1134 if (!drv)
1156 1135 return NULL;
1157 1136  
1158   - /* XXX: we assume that nb_sectors == 0 is suppored by the async read */
1159   - if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
1160   - memcpy(buf, bs->boot_sector_data, 512);
1161   - sector_num++;
1162   - nb_sectors--;
1163   - buf += 512;
1164   - }
1165   -
1166 1137 ret = drv->bdrv_aio_read(bs, sector_num, buf, nb_sectors, cb, opaque);
1167 1138  
1168 1139 if (ret) {
... ... @@ -1185,9 +1156,6 @@ BlockDriverAIOCB *bdrv_aio_write(BlockDriverState *bs, int64_t sector_num,
1185 1156 return NULL;
1186 1157 if (bs->read_only)
1187 1158 return NULL;
1188   - if (sector_num == 0 && bs->boot_sector_enabled && nb_sectors > 0) {
1189   - memcpy(bs->boot_sector_data, buf, 512);
1190   - }
1191 1159  
1192 1160 ret = drv->bdrv_aio_write(bs, sector_num, buf, nb_sectors, cb, opaque);
1193 1161  
... ...
... ... @@ -79,7 +79,6 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset);
79 79 int64_t bdrv_getlength(BlockDriverState *bs);
80 80 void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr);
81 81 int bdrv_commit(BlockDriverState *bs);
82   -void bdrv_set_boot_sector(BlockDriverState *bs, const uint8_t *data, int size);
83 82 /* async block I/O */
84 83 typedef struct BlockDriverAIOCB BlockDriverAIOCB;
85 84 typedef void BlockDriverCompletionFunc(void *opaque, int ret);
... ...
block_int.h
  View file @4fc9af5
... ... @@ -104,9 +104,6 @@ struct BlockDriverState {
104 104 BlockDriver *drv; /* NULL means no media */
105 105 void *opaque;
106 106  
107   - int boot_sector_enabled;
108   - uint8_t boot_sector_data[512];
109   -
110 107 char filename[1024];
111 108 char backing_file[1024]; /* if non zero, the image is a diff of
112 109 this file image */
... ...
... ... @@ -438,30 +438,45 @@ static void bochs_bios_init(void)
438 438  
439 439 /* Generate an initial boot sector which sets state and jump to
440 440 a specified vector */
441   -static void generate_bootsect(uint32_t gpr[8], uint16_t segs[6], uint16_t ip)
  441 +static void generate_bootsect(uint8_t *option_rom,
  442 + uint32_t gpr[8], uint16_t segs[6], uint16_t ip)
442 443 {
443   - uint8_t bootsect[512], *p;
  444 + uint8_t rom[512], *p, *reloc;
  445 + uint8_t sum;
444 446 int i;
445   - int hda;
446 447  
447   - hda = drive_get_index(IF_IDE, 0, 0);
448   - if (hda == -1) {
449   - fprintf(stderr, "A disk image must be given for 'hda' when booting "
450   - "a Linux kernel\n(if you really don't want it, use /dev/zero)\n");
451   - exit(1);
452   - }
  448 + memset(rom, 0, sizeof(rom));
  449 +
  450 + p = rom;
  451 + /* Make sure we have an option rom signature */
  452 + *p++ = 0x55;
  453 + *p++ = 0xaa;
453 454  
454   - memset(bootsect, 0, sizeof(bootsect));
  455 + /* ROM size in sectors*/
  456 + *p++ = 1;
455 457  
456   - /* Copy the MSDOS partition table if possible */
457   - bdrv_read(drives_table[hda].bdrv, 0, bootsect, 1);
  458 + /* Hook int19 */
458 459  
459   - /* Make sure we have a partition signature */
460   - bootsect[510] = 0x55;
461   - bootsect[511] = 0xaa;
  460 + *p++ = 0x50; /* push ax */
  461 + *p++ = 0x1e; /* push ds */
  462 + *p++ = 0x31; *p++ = 0xc0; /* xor ax, ax */
  463 + *p++ = 0x8e; *p++ = 0xd8; /* mov ax, ds */
462 464  
  465 + *p++ = 0xc7; *p++ = 0x06; /* movvw _start,0x64 */
  466 + *p++ = 0x64; *p++ = 0x00;
  467 + reloc = p;
  468 + *p++ = 0x00; *p++ = 0x00;
  469 +
  470 + *p++ = 0x8c; *p++ = 0x0e; /* mov cs,0x66 */
  471 + *p++ = 0x66; *p++ = 0x00;
  472 +
  473 + *p++ = 0x1f; /* pop ds */
  474 + *p++ = 0x58; /* pop ax */
  475 + *p++ = 0xcb; /* lret */
  476 +
463 477 /* Actual code */
464   - p = bootsect;
  478 + *reloc = (p - rom);
  479 +
465 480 *p++ = 0xfa; /* CLI */
466 481 *p++ = 0xfc; /* CLD */
467 482  
... ... @@ -491,7 +506,13 @@ static void generate_bootsect(uint32_t gpr[8], uint16_t segs[6], uint16_t ip)
491 506 *p++ = segs[1]; /* CS */
492 507 *p++ = segs[1] >> 8;
493 508  
494   - bdrv_set_boot_sector(drives_table[hda].bdrv, bootsect, sizeof(bootsect));
  509 + /* sign rom */
  510 + sum = 0;
  511 + for (i = 0; i < (sizeof(rom) - 1); i++)
  512 + sum += rom[i];
  513 + rom[sizeof(rom) - 1] = -sum;
  514 +
  515 + memcpy(option_rom, rom, sizeof(rom));
495 516 }
496 517  
497 518 static long get_file_size(FILE *f)
... ... @@ -508,7 +529,8 @@ static long get_file_size(FILE *f)
508 529 return size;
509 530 }
510 531  
511   -static void load_linux(const char *kernel_filename,
  532 +static void load_linux(uint8_t *option_rom,
  533 + const char *kernel_filename,
512 534 const char *initrd_filename,
513 535 const char *kernel_cmdline)
514 536 {
... ... @@ -658,7 +680,7 @@ static void load_linux(const char *kernel_filename,
658 680 memset(gpr, 0, sizeof gpr);
659 681 gpr[4] = cmdline_addr-real_addr-16; /* SP (-16 is paranoia) */
660 682  
661   - generate_bootsect(gpr, seg, 0);
  683 + generate_bootsect(option_rom, gpr, seg, 0);
662 684 }
663 685  
664 686 static void main_cpu_reset(void *opaque)
... ... @@ -862,6 +884,15 @@ static void pc_init1(ram_addr_t ram_size, int vga_ram_size,
862 884 int size, offset;
863 885  
864 886 offset = 0;
  887 + if (linux_boot) {
  888 + option_rom_offset = qemu_ram_alloc(TARGET_PAGE_SIZE);
  889 + load_linux(phys_ram_base + option_rom_offset,
  890 + kernel_filename, initrd_filename, kernel_cmdline);
  891 + cpu_register_physical_memory(0xd0000, TARGET_PAGE_SIZE,
  892 + option_rom_offset | IO_MEM_ROM);
  893 + offset = TARGET_PAGE_SIZE;
  894 + }
  895 +
865 896 for (i = 0; i < nb_option_roms; i++) {
866 897 size = get_image_size(option_rom[i]);
867 898 if (size < 0) {
... ... @@ -891,9 +922,6 @@ static void pc_init1(ram_addr_t ram_size, int vga_ram_size,
891 922  
892 923 bochs_bios_init();
893 924  
894   - if (linux_boot)
895   - load_linux(kernel_filename, initrd_filename, kernel_cmdline);
896   -
897 925 cpu_irq = qemu_allocate_irqs(pic_irq_request, NULL, 1);
898 926 i8259 = i8259_init(cpu_irq[0]);
899 927 ferr_irq = i8259[13];
... ...