memdisk/setup.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2001-2006 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   8  *   Boston MA 02111-1307, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 #include <stdint.h>
  14 #include "e820.h"
  15 #include "conio.h"
  16 #include "version.h"
  17 #include "memdisk.h"
  18
  19 const char memdisk_version[] =
  20 "MEMDISK " VERSION " " DATE;
  21 const char copyright[] =
  22 "Copyright " FIRSTYEAR "-" COPYYEAR " H. Peter Anvin";
  23
  24 extern const char _binary_memdisk_bin_start[], _binary_memdisk_bin_end[];
  25 extern const char _binary_memdisk_bin_size[]; /* Weird, I know */
  26
  27 struct memdisk_header {
  28   uint16_t int13_offs;
  29   uint16_t int15_offs;
  30   uint16_t patch_offs;
  31   uint16_t total_size;
  32 };
  33
  34 /* The Disk Parameter Table may be required */
  35 typedef union {
  36   struct hd_dpt {
  37     uint16_t max_cyl;           /* Max cylinder */
  38     uint8_t max_head;           /* Max head */
  39     uint8_t junk1[5];           /* Obsolete junk, leave at zero */
  40     uint8_t ctrl;               /* Control byte */
  41     uint8_t junk2[7];           /* More obsolete junk */
  42   } hd;
  43   struct fd_dpt {
  44     uint8_t specify1;           /* "First specify byte" */
  45     uint8_t specify2;           /* "Second specify byte" */
  46     uint8_t delay;              /* Delay until motor turn off */
  47     uint8_t sectors;            /* Sectors/track */
  48
  49     uint8_t bps;                /* Bytes/sector (02h = 512) */
  50     uint8_t isgap;              /* Length of intersector gap */
  51     uint8_t dlen;               /* Data length (0FFh) */
  52     uint8_t fgap;               /* Formatting gap */
  53
  54     uint8_t ffill;              /* Format fill byte */
  55     uint8_t settle;             /* Head settle time (ms) */
  56     uint8_t mstart;             /* Motor start time */
  57     uint8_t _pad1;              /* Padding */
  58
  59     uint32_t old_fd_dpt;        /* Extension: pointer to old INT 1Eh */
  60   } fd;
  61 } dpt_t;
  62
  63 struct patch_area {
  64   uint32_t diskbuf;
  65   uint32_t disksize;
  66   uint16_t cmdline_off, cmdline_seg;
  67
  68   uint32_t oldint13;
  69   uint32_t oldint15;
  70
  71   uint16_t olddosmem;
  72   uint8_t  bootloaderid;
  73
  74   uint8_t  _pad[3];
  75   uint16_t memint1588;
  76
  77   uint16_t cylinders;
  78   uint16_t heads;
  79   uint32_t sectors;
  80
  81   uint32_t mem1mb;
  82   uint32_t mem16mb;
  83
  84   uint8_t  driveno;
  85   uint8_t  drivetype;
  86   uint8_t  drivecnt;
  87   uint8_t  configflags;
  88
  89 #define CONFIG_READONLY 0x01
  90 #define CONFIG_RAW      0x02
  91 #define CONFIG_SAFEINT  0x04
  92 #define CONFIG_BIGRAW   0x08            /* MUST be 8! */
  93
  94   uint16_t mystack;
  95   uint16_t statusptr;
  96
  97   dpt_t dpt;
  98 };
  99
 100 /* This is the header in the boot sector/setup area */
 101 struct setup_header {
 102   char cmdline[0x1f1];
 103   uint8_t setup_secs;
 104   uint16_t syssize;
 105   uint16_t swap_dev;
 106   uint16_t ram_size;
 107   uint16_t vid_mode;
 108   uint16_t root_dev;
 109   uint16_t boot_flag;
 110   uint16_t jump;
 111   char header[4];
 112   uint16_t version;
 113   uint32_t realmode_swtch;
 114   uint32_t start_sys;
 115   uint8_t type_of_loader;
 116   uint8_t loadflags;
 117   uint16_t setup_move_size;
 118   uint32_t code32_start;
 119   uint32_t ramdisk_image;
 120   uint32_t ramdisk_size;
 121   uint32_t bootsect_kludge;
 122   uint16_t head_end_ptr;
 123   uint16_t pad1;
 124   uint32_t cmd_line_ptr;
 125   uint32_t initrd_addr_max;
 126   uint32_t esdi;
 127   uint32_t edx;
 128 };
 129
 130 struct setup_header * const shdr = (struct setup_header *)(LOW_SEG << 4);
 131
 132 /* Access to high memory */
 133
 134 /* Access to objects in the zero page */
 135 static inline void
 136 wrz_8(uint32_t addr, uint8_t data)
 137 {
 138   *((uint8_t *)addr) = data;
 139 }
 140 static inline void
 141 wrz_16(uint32_t addr, uint16_t data)
 142 {
 143   *((uint16_t *)addr) = data;
 144 }
 145 static inline void
 146 wrz_32(uint32_t addr, uint32_t data)
 147 {
 148   *((uint32_t *)addr) = data;
 149 }
 150 static inline uint8_t
 151 rdz_8(uint32_t addr)
 152 {
 153   return *((uint8_t *)addr);
 154 }
 155 static inline uint16_t
 156 rdz_16(uint32_t addr)
 157 {
 158   return *((uint16_t *)addr);
 159 }
 160 static inline uint32_t
 161 rdz_32(uint32_t addr)
 162 {
 163   return *((uint32_t *)addr);
 164 }
 165
 166 /* Addresses in the zero page */
 167 #define BIOS_INT13      (0x13*4) /* INT 13h vector */
 168 #define BIOS_INT15      (0x15*4) /* INT 15h vector */
 169 #define BIOS_INT1E      (0x1E*4) /* INT 1Eh vector */
 170 #define BIOS_INT40      (0x40*4) /* INT 13h vector */
 171 #define BIOS_INT41      (0x41*4) /* INT 41h vector */
 172 #define BIOS_INT46      (0x46*4) /* INT 46h vector */
 173 #define BIOS_BASEMEM    0x413    /* Amount of DOS memory */
 174 #define BIOS_EQUIP      0x410    /* BIOS equipment list */
 175 #define BIOS_HD_COUNT   0x475    /* Number of hard drives present */
 176
 177 /*
 178  * Routine to seek for a command-line item and return a pointer
 179  * to the data portion, if present
 180  */
 181
 182 /* Magic return values */
 183 #define CMD_NOTFOUND   ((char *)-1) /* Not found */
 184 #define CMD_BOOL       ((char *)-2) /* Found boolean option */
 185 #define CMD_HASDATA(X) ((int)(X) >= 0)
 186
 187 const char *getcmditem(const char *what)
 188 {
 189   const char *p;
 190   const char *wp = what;
 191   int match = 0;
 192
 193   for ( p = shdr->cmdline ; *p ; p++ ) {
 194     switch ( match ) {
 195     case 0:                     /* Ground state */
 196       if ( *p == ' ' )
 197         break;
 198
 199       wp = what;
 200       match = 1;
 201       /* Fall through */
 202
 203     case 1:                     /* Matching */
 204       if ( *wp == '\0' ) {
 205         if ( *p == '=' )
 206           return p+1;
 207         else if ( *p == ' ' )
 208           return CMD_BOOL;
 209         else {
 210           match = 2;
 211           break;
 212         }
 213       }
 214       if ( *p != *wp++ )
 215         match = 2;
 216       break;
 217
 218     case 2:                     /* Mismatch, skip rest of option */
 219       if ( *p == ' ' )
 220         match = 0;              /* Next option */
 221       break;
 222     }
 223   }
 224
 225   /* Check for matching string at end of line */
 226   if ( match == 1 && *wp == '\0' )
 227     return CMD_BOOL;
 228
 229   return CMD_NOTFOUND;
 230 }
 231
 232 /*
 233  * Check to see if this is a gzip image
 234  */
 235 #define UNZIP_ALIGN 512
 236
 237 extern void _end;               /* Symbol signalling end of data */
 238
 239 void unzip_if_needed(uint32_t *where_p, uint32_t *size_p)
 240 {
 241   uint32_t where = *where_p;
 242   uint32_t size = *size_p;
 243   uint32_t zbytes;
 244   uint32_t startrange, endrange;
 245   uint32_t gzdatasize, gzwhere;
 246   uint32_t orig_crc, offset;
 247   uint32_t target = 0;
 248   int i, okmem;
 249
 250   /* Is it a gzip image? */
 251   if (check_zip ((void *)where, size, &zbytes, &gzdatasize,
 252                  &orig_crc, &offset) == 0) {
 253
 254     if (offset + zbytes > size) {
 255       /* Assertion failure; check_zip is supposed to guarantee this
 256          never happens. */
 257       puts("internal error: check_zip returned nonsense\n");
 258       die();
 259     }
 260
 261     /* Find a good place to put it: search memory ranges in descending order
 262        until we find one that is legal and fits */
 263     okmem = 0;
 264     for ( i = nranges-1 ; i >= 0 ; i-- ) {
 265       /* We can't use > 4G memory (32 bits only.)  Truncate to 2^32-1
 266          so we don't have to deal with funny wraparound issues. */
 267
 268       /* Must be memory */
 269       if ( ranges[i].type != 1 )
 270         continue;
 271
 272       /* Range start */
 273       if ( ranges[i].start >= 0xFFFFFFFF )
 274         continue;
 275       startrange = (uint32_t)ranges[i].start;
 276
 277       /* Range end (0 for end means 2^64) */
 278       endrange = ((ranges[i+1].start >= 0xFFFFFFFF ||
 279                    ranges[i+1].start == 0)
 280                   ? 0xFFFFFFFF : (uint32_t)ranges[i+1].start);
 281
 282       /* Make sure we don't overwrite ourselves */
 283       if ( startrange < (uint32_t)&_end )
 284         startrange = (uint32_t)&_end;
 285
 286       /* Allow for alignment */
 287       startrange = (ranges[i].start + (UNZIP_ALIGN-1)) & ~(UNZIP_ALIGN-1);
 288
 289       /* In case we just killed the whole range... */
 290       if ( startrange >= endrange )
 291         continue;
 292
 293       /* Must be large enough... don't rely on gzwhere for this (wraparound) */
 294       if ( endrange-startrange < gzdatasize )
 295         continue;
 296
 297       /* This is where the gz image should be put if we put it in this range */
 298       gzwhere = (endrange - gzdatasize) & ~(UNZIP_ALIGN-1);
 299
 300       /* Cast to uint64_t just in case we're flush with the top byte */
 301       if ( (uint64_t)where+size >= gzwhere && where < endrange ) {
 302         /* Need to move source data to avoid compressed/uncompressed overlap */
 303         uint32_t newwhere;
 304
 305         if ( gzwhere-startrange < size )
 306           continue;             /* Can't fit both old and new */
 307
 308         newwhere = (gzwhere - size) & ~(UNZIP_ALIGN-1);
 309         printf("Moving compressed data from 0x%08x to 0x%08x\n",
 310                where, newwhere);
 311
 312         /* Our memcpy() is OK, because we always move from a higher
 313            address to a lower one */
 314         memcpy((void *)newwhere, (void *)where, size);
 315         where = newwhere;
 316       }
 317
 318       target = gzwhere;
 319       okmem = 1;
 320       break;
 321     }
 322
 323     if ( !okmem ) {
 324       printf("Not enough memory to decompress image (need 0x%08x bytes)\n",
 325              gzdatasize);
 326       die();
 327     }
 328
 329     printf("gzip image: decompressed addr 0x%08x, len 0x%08x: ",
 330            target, gzdatasize);
 331
 332     *size_p  = gzdatasize;
 333     *where_p = (uint32_t)unzip((void *)(where + offset), zbytes,
 334                                gzdatasize, orig_crc, (void *)target);
 335   }
 336 }
 337
 338 /*
 339  * Figure out the "geometry" of the disk in question
 340  */
 341 struct geometry {
 342   uint32_t sectors;             /* 512-byte sector count */
 343   uint32_t c, h, s;             /* C/H/S geometry */
 344   uint32_t offset;              /* Byte offset for disk */
 345   uint8_t type;                 /* Type byte for INT 13h AH=08h */
 346   uint8_t driveno;              /* Drive no */
 347 };
 348
 349 static const struct geometry geometries[] =
 350 {
 351   {  360*2, 40,  2,  9, 0, 0x01, 0 }, /*  360 K */
 352   {  720*2, 80,  2,  9, 0, 0x03, 0 }, /*  720 K*/
 353   { 1200*2, 80,  2, 15, 0, 0x02, 0 }, /* 1200 K */
 354   { 1440*2, 80,  2, 18, 0, 0x04, 0 }, /* 1440 K */
 355   { 1680*2, 80,  2, 21, 0, 0x04, 0 }, /* 1680 K */
 356   { 1722*2, 82,  2, 21, 0, 0x04, 0 }, /* 1722 K */
 357   { 2880*2, 80,  2, 36, 0, 0x06, 0 }, /* 2880 K */
 358   { 3840*2, 80,  2, 48, 0, 0x06, 0 }, /* 3840 K */
 359 };
 360 #define known_geometries (sizeof(geometries)/sizeof(struct geometry))
 361
 362 /* Format of a DOS partition table entry */
 363 struct ptab_entry {
 364   uint8_t active;
 365   uint8_t start_h, start_s, start_c;
 366   uint8_t type;
 367   uint8_t end_h, end_s, end_c;
 368   uint32_t start;
 369   uint32_t size;
 370 };
 371
 372 /* Format of a DOSEMU header */
 373 struct dosemu_header {
 374   uint8_t magic[7];             /* DOSEMU\0 */
 375   uint32_t h;
 376   uint32_t s;
 377   uint32_t c;
 378   uint32_t offset;
 379   uint8_t pad[105];
 380 } __attribute__((packed));
 381
 382 #define FOUR(a,b,c,d) (((a) << 24)|((b) << 16)|((c) << 8)|(d))
 383
 384 const struct geometry *get_disk_image_geometry(uint32_t where, uint32_t size)
 385 {
 386   static struct geometry hd_geometry = { 0, 0, 0, 0, 0, 0, 0x80 };
 387   struct ptab_entry ptab[4];    /* Partition table buffer */
 388   struct dosemu_header dosemu;
 389   unsigned int sectors, v;
 390   unsigned int max_c, max_h, max_s;
 391   unsigned int c, h, s, offset;
 392   int i;
 393   int drive_specified;
 394   const char *p;
 395
 396   printf("command line: %s\n", shdr->cmdline);
 397
 398   offset = 0;
 399   if ( CMD_HASDATA(p = getcmditem("offset")) && (v = atou(p)) )
 400     offset = v;
 401
 402   sectors = (size-offset) >> 9;
 403   for ( i = 0 ; i < known_geometries ; i++ ) {
 404     if ( sectors == geometries[i].sectors ) {
 405       hd_geometry = geometries[i];
 406       break;
 407     }
 408   }
 409
 410   hd_geometry.sectors = sectors;
 411   hd_geometry.offset  = offset;
 412
 413   /* Do we have a DOSEMU header? */
 414   memcpy(&dosemu, (char *)where+hd_geometry.offset, sizeof dosemu);
 415   if ( !memcmp("DOSEMU", dosemu.magic, 7) ) {
 416     /* Always a hard disk unless overruled by command-line options */
 417     hd_geometry.driveno = 0x80;
 418     hd_geometry.type = 0;
 419     hd_geometry.c = dosemu.c;
 420     hd_geometry.h = dosemu.h;
 421     hd_geometry.s = dosemu.s;
 422     hd_geometry.offset += dosemu.offset;
 423     sectors = (size-hd_geometry.offset) >> 9;
 424   }
 425
 426   if ( CMD_HASDATA(p = getcmditem("c")) && (v = atou(p)) )
 427     hd_geometry.c = v;
 428   if ( CMD_HASDATA(p = getcmditem("h")) && (v = atou(p)) )
 429     hd_geometry.h = v;
 430   if ( CMD_HASDATA(p = getcmditem("s")) && (v = atou(p)) )
 431     hd_geometry.s = v;
 432
 433   if ( (p = getcmditem("floppy")) != CMD_NOTFOUND ) {
 434     hd_geometry.driveno = CMD_HASDATA(p) ? atou(p) & 0x7f : 0;
 435     if ( hd_geometry.type == 0 )
 436       hd_geometry.type = 0x10;  /* ATAPI floppy, e.g. LS-120 */
 437     drive_specified = 1;
 438   } else if ( (p = getcmditem("harddisk")) != CMD_NOTFOUND ) {
 439     hd_geometry.driveno = CMD_HASDATA(p) ? atou(p) | 0x80 : 0x80;
 440     hd_geometry.type = 0;
 441     drive_specified = 1;
 442   }
 443
 444   if ( (hd_geometry.c == 0) || (hd_geometry.h == 0) ||
 445        (hd_geometry.s == 0) ) {
 446     /* Hard disk image, need to examine the partition table for geometry */
 447     memcpy(&ptab, (char *)where+hd_geometry.offset+(512-2-4*16), sizeof ptab);
 448
 449     max_c = max_h = 0;  max_s = 1;
 450     for ( i = 0 ; i < 4 ; i++ ) {
 451       if ( ptab[i].type ) {
 452         c = ptab[i].start_c + (ptab[i].start_s >> 6);
 453         s = (ptab[i].start_s & 0x3f);
 454         h = ptab[i].start_h;
 455
 456         if ( max_c < c ) max_c = c;
 457         if ( max_h < h ) max_h = h;
 458         if ( max_s < s ) max_s = s;
 459
 460         c = ptab[i].end_c + (ptab[i].end_s >> 6);
 461         s = (ptab[i].end_s & 0x3f);
 462         h = ptab[i].end_h;
 463
 464         if ( max_c < c ) max_c = c;
 465         if ( max_h < h ) max_h = h;
 466         if ( max_s < s ) max_s = s;
 467       }
 468     }
 469
 470     max_c++; max_h++;           /* Convert to count (1-based) */
 471
 472     if ( !hd_geometry.h )
 473       hd_geometry.h = max_h;
 474     if ( !hd_geometry.s )
 475       hd_geometry.s = max_s;
 476     if ( !hd_geometry.c )
 477       hd_geometry.c = sectors/(hd_geometry.h*hd_geometry.s);
 478   }
 479
 480   if ( (size-hd_geometry.offset) & 0x1ff ) {
 481     puts("MEMDISK: Image has fractional end sector\n");
 482   }
 483   if ( sectors % (hd_geometry.h*hd_geometry.s) ) {
 484     puts("MEMDISK: Image seems to have fractional end cylinder\n");
 485   }
 486   if ( (hd_geometry.c*hd_geometry.h*hd_geometry.s) > sectors ) {
 487     puts("MEMDISK: Image appears to be truncated\n");
 488   }
 489
 490   return &hd_geometry;
 491 }
 492
 493 /*
 494  * Jump here if all hope is gone...
 495  */
 496 void __attribute__((noreturn)) die(void)
 497 {
 498   asm volatile("sti");
 499   for(;;)
 500     asm volatile("hlt");
 501 }
 502
 503 /*
 504  * Find a $PnP installation check structure; return (ES << 16) + DI value
 505  */
 506 static uint32_t pnp_install_check(void)
 507 {
 508   uint32_t *seg;
 509   unsigned char *p, csum;
 510   int i, len;
 511
 512   for (seg = (uint32_t *)0xf0000; seg < (uint32_t *)0x100000; seg += 4) {
 513     if (*seg == ('$'+('P' << 8)+('n' << 16)+('P' << 24))) {
 514       p = (unsigned char *)seg;
 515       len = p[5];
 516       if (len < 0x21)
 517         continue;
 518       csum = 0;
 519       for (i = len; i; i--)
 520         csum += *p++;
 521       if (csum != 0)
 522         continue;
 523
 524       return (0xf000 << 16) + (uint16_t)(unsigned long)seg;
 525     }
 526   }
 527
 528   return 0;
 529 }
 530
 531 #define STACK_NEEDED    512     /* Number of bytes of stack */
 532
 533 /*
 534  * Actual setup routine
 535  * Returns the drive number (which is then passed in %dl to the
 536  * called routine.)
 537  */
 538 syscall_t syscall;
 539 void *sys_bounce;
 540
 541 void setup(syscall_t cs_syscall, void *cs_bounce)
 542 {
 543   unsigned int bin_size = (int) &_binary_memdisk_bin_size;
 544   struct memdisk_header *hptr;
 545   struct patch_area *pptr;
 546   uint16_t driverseg;
 547   uint32_t driverptr, driveraddr;
 548   uint16_t dosmem_k;
 549   uint32_t stddosmem;
 550   const struct geometry *geometry;
 551   int total_size, cmdlinelen;
 552   com32sys_t regs;
 553   uint32_t ramdisk_image, ramdisk_size;
 554   int bios_drives;
 555
 556   /* Set up global variables */
 557   syscall = cs_syscall;
 558   sys_bounce = cs_bounce;
 559
 560   /* Show signs of life */
 561   printf("%s  %s\n", memdisk_version, copyright);
 562
 563   if ( !shdr->ramdisk_image || !shdr->ramdisk_size ) {
 564     puts("MEMDISK: No ramdisk image specified!\n");
 565     die();
 566   }
 567
 568   ramdisk_image = shdr->ramdisk_image;
 569   ramdisk_size  = shdr->ramdisk_size;
 570
 571   e820map_init();               /* Initialize memory data structure */
 572   get_mem();                    /* Query BIOS for memory map */
 573   parse_mem();                  /* Parse memory map */
 574
 575   printf("Ramdisk at 0x%08x, length 0x%08x\n",
 576          ramdisk_image, ramdisk_size);
 577
 578   unzip_if_needed(&ramdisk_image, &ramdisk_size);
 579
 580   geometry = get_disk_image_geometry(ramdisk_image, ramdisk_size);
 581
 582   printf("Disk is %s %d, %u K, C/H/S = %u/%u/%u\n",
 583          (geometry->driveno & 0x80) ? "hard disk" : "floppy",
 584          geometry->driveno & 0x7f,
 585          geometry->sectors >> 1,
 586          geometry->c, geometry->h, geometry->s);
 587
 588   /* Reserve the ramdisk memory */
 589   insertrange(ramdisk_image, ramdisk_size, 2);
 590   parse_mem();                  /* Recompute variables */
 591
 592   /* Figure out where it needs to go */
 593   hptr = (struct memdisk_header *) &_binary_memdisk_bin_start;
 594   pptr = (struct patch_area *)(_binary_memdisk_bin_start + hptr->patch_offs);
 595
 596   dosmem_k = rdz_16(BIOS_BASEMEM);
 597   pptr->olddosmem = dosmem_k;
 598   stddosmem = dosmem_k << 10;
 599   /* If INT 15 E820 and INT 12 disagree, go with the most conservative */
 600   if ( stddosmem > dos_mem )
 601     stddosmem = dos_mem;
 602
 603   pptr->driveno   = geometry->driveno;
 604   pptr->drivetype = geometry->type;
 605   pptr->cylinders = geometry->c;
 606   pptr->heads     = geometry->h;
 607   pptr->sectors   = geometry->s;
 608   pptr->disksize  = geometry->sectors;
 609   pptr->diskbuf   = ramdisk_image + geometry->offset;
 610   pptr->statusptr = (geometry->driveno & 0x80) ? 0x474 : 0x441;
 611
 612   pptr->bootloaderid = shdr->type_of_loader;
 613
 614   pptr->configflags = 0;
 615   /* Set config flags */
 616   if ( getcmditem("ro") != CMD_NOTFOUND ) {
 617     puts("Marking disk readonly\n");
 618     pptr->configflags |= CONFIG_READONLY;
 619   }
 620   if ( getcmditem("raw") != CMD_NOTFOUND ) {
 621     puts("Using raw access to high memory\n");
 622     pptr->configflags &= ~CONFIG_SAFEINT|CONFIG_BIGRAW;
 623     pptr->configflags |= CONFIG_RAW;
 624   }
 625   if ( getcmditem("safeint") != CMD_NOTFOUND ) {
 626     puts("Using safe INT 15h access to high memory\n");
 627     pptr->configflags &= ~CONFIG_RAW|CONFIG_BIGRAW;
 628     pptr->configflags |= CONFIG_SAFEINT;
 629   }
 630   if ( getcmditem("bigraw") != CMD_NOTFOUND ) {
 631     puts("Using raw access to high memory - assuming big real mode\n");
 632     pptr->configflags &= ~CONFIG_SAFEINT;
 633     pptr->configflags |= CONFIG_BIGRAW|CONFIG_RAW;
 634   }
 635
 636   /* Set up a drive parameter table */
 637   if ( geometry->driveno & 0x80 ) {
 638     /* Hard disk */
 639     pptr->dpt.hd.max_cyl  = geometry->c-1;
 640     pptr->dpt.hd.max_head = geometry->h-1;
 641     pptr->dpt.hd.ctrl     = (geometry->h > 8) ? 0x08: 0;
 642   } else {
 643     /* Floppy - most of these fields are bogus and mimic
 644        a 1.44 MB floppy drive */
 645     pptr->dpt.fd.specify1 = 0xdf;
 646     pptr->dpt.fd.specify2 = 0x02;
 647     pptr->dpt.fd.delay    = 0x25;
 648     pptr->dpt.fd.sectors  = geometry->s;
 649     pptr->dpt.fd.bps      = 0x02;
 650     pptr->dpt.fd.isgap    = 0x12;
 651     pptr->dpt.fd.dlen     = 0xff;
 652     pptr->dpt.fd.fgap     = 0x6c;
 653     pptr->dpt.fd.ffill    = 0xf6;
 654     pptr->dpt.fd.settle   = 0x0f;
 655     pptr->dpt.fd.mstart   = 0x05;
 656
 657     pptr->dpt.fd.old_fd_dpt = rdz_32(BIOS_INT1E);
 658   }
 659
 660   /* The size is given by hptr->total_size plus the size of the E820
 661      map -- 12 bytes per range; we may need as many as 2 additional
 662      ranges (each insertrange() can worst-case turn 1 area into 3)
 663      plus the terminating range, over what nranges currently show. */
 664   cmdlinelen = strlen(shdr->cmdline)+1;
 665   total_size  =  hptr->total_size;              /* Actual memdisk code */
 666   total_size += (nranges+3)*sizeof(ranges[0]);  /* E820 memory ranges */
 667   total_size += cmdlinelen;                     /* Command line */
 668   total_size += STACK_NEEDED;                   /* Stack */
 669   printf("Total size needed = %u bytes, allocating %uK\n",
 670          total_size, (total_size+0x3ff) >> 10);
 671
 672   if ( total_size > dos_mem ) {
 673     puts("MEMDISK: Insufficient low memory\n");
 674     die();
 675   }
 676
 677   driveraddr  = stddosmem - total_size;
 678   driveraddr &= ~0x3FF;
 679
 680   printf("Old dos memory at 0x%05x (map says 0x%05x), loading at 0x%05x\n",
 681          stddosmem, dos_mem, driveraddr);
 682
 683   /* Reserve this range of memory */
 684   wrz_16(BIOS_BASEMEM, driveraddr >> 10);
 685   insertrange(driveraddr, dos_mem-driveraddr, 2);
 686   parse_mem();
 687
 688   pptr->mem1mb     = low_mem  >> 10;
 689   pptr->mem16mb    = high_mem >> 16;
 690   if ( low_mem == (15 << 20) ) {
 691     /* lowmem maxed out */
 692     uint32_t int1588mem = (high_mem >> 10)+(low_mem >> 10);
 693     pptr->memint1588 = (int1588mem > 0xffff) ? 0xffff : int1588mem;
 694   } else {
 695     pptr->memint1588 = low_mem >> 10;
 696   }
 697
 698   printf("1588: 0x%04x  15E801: 0x%04x 0x%04x\n",
 699          pptr->memint1588, pptr->mem1mb, pptr->mem16mb);
 700
 701   driverseg = driveraddr >> 4;
 702   driverptr = driverseg  << 16;
 703
 704   /* Anything beyond the end is for the stack */
 705   pptr->mystack    = (uint16_t)(stddosmem-driveraddr);
 706
 707   pptr->oldint13 = rdz_32(BIOS_INT13);
 708   pptr->oldint15 = rdz_32(BIOS_INT15);
 709
 710   /* Adjust the E820 table: if there are null ranges (type 0)
 711      at the end, change them to type end of list (-1).
 712      This is necessary for the driver to be able to report end
 713      of list correctly. */
 714   while ( nranges && ranges[nranges-1].type == 0 ) {
 715     ranges[--nranges].type = -1;
 716   }
 717
 718   /* Query drive parameters of this type */
 719   memset(&regs, 0, sizeof regs);
 720   regs.es = 0;
 721   regs.eax.b[1] = 0x08;
 722   regs.edx.b[0] = geometry->driveno & 0x80;
 723   syscall(0x13, &regs, &regs);
 724
 725   if ( regs.eflags.l & 1 ) {
 726     printf("INT 13 08: Failure, assuming this is the only drive\n");
 727     pptr->drivecnt = 0;
 728   } else {
 729     printf("INT 13 08: Success, count = %u, BPT = %04x:%04x\n",
 730            regs.edx.b[0], regs.es, regs.edi.w[0]);
 731     pptr->drivecnt = regs.edx.b[0];
 732   }
 733
 734   /* Compare what INT 13h returned with the appropriate equipment byte */
 735   if ( geometry->driveno & 0x80 ) {
 736     bios_drives = rdz_8(BIOS_HD_COUNT);
 737   } else {
 738     uint8_t equip = rdz_8(BIOS_EQUIP);
 739
 740     if (equip & 1)
 741       bios_drives = (equip >> 6)+1;
 742     else
 743       bios_drives = 0;
 744   }
 745
 746   if (pptr->drivecnt > bios_drives) {
 747     printf("BIOS equipment byte says count = %d, go with that\n", bios_drives);
 748     pptr->drivecnt = bios_drives;
 749   }
 750
 751   /* Discontiguous drive space.  There is no really good solution for this. */
 752   if ( pptr->drivecnt <= (geometry->driveno & 0x7f) )
 753     pptr->drivecnt = (geometry->driveno & 0x7f) + 1;
 754
 755   /* Pointer to the command line */
 756   pptr->cmdline_off = bin_size + (nranges+1)*sizeof(ranges[0]);
 757   pptr->cmdline_seg = driverseg;
 758
 759   /* Copy driver followed by E820 table followed by command line */
 760   {
 761     unsigned char *dpp = (unsigned char *)(driverseg << 4);
 762     dpp = memcpy_endptr(dpp, &_binary_memdisk_bin_start, bin_size);
 763     dpp = memcpy_endptr(dpp, ranges, (nranges+1)*sizeof(ranges[0]));
 764     dpp = memcpy_endptr(dpp, shdr->cmdline, cmdlinelen+1);
 765   }
 766
 767   /* Install the interrupt handlers */
 768   printf("old: int13 = %08x  int15 = %08x\n",
 769          rdz_32(BIOS_INT13), rdz_32(BIOS_INT15));
 770
 771   wrz_32(BIOS_INT13, driverptr+hptr->int13_offs);
 772   wrz_32(BIOS_INT15, driverptr+hptr->int15_offs);
 773
 774   printf("new: int13 = %08x  int15 = %08x\n",
 775          rdz_32(BIOS_INT13), rdz_32(BIOS_INT15));
 776
 777   /* Update various BIOS magic data areas (gotta love this shit) */
 778
 779   if ( geometry->driveno & 0x80 ) {
 780     /* Update BIOS hard disk count */
 781     uint8_t nhd = pptr->drivecnt;
 782
 783     if ( nhd > 128 )
 784       nhd = 128;
 785
 786     wrz_8(BIOS_HD_COUNT, nhd);
 787   } else {
 788     /* Update BIOS floppy disk count */
 789     uint8_t equip = rdz_8(BIOS_EQUIP);
 790     uint8_t nflop = pptr->drivecnt;
 791
 792     if ( nflop > 4 )            /* Limit of equipment byte */
 793       nflop = 4;
 794
 795     equip &= 0x3E;
 796     if ( nflop )
 797       equip |= ((nflop-1) << 6) | 0x01;
 798
 799     wrz_8(BIOS_EQUIP, equip);
 800   }
 801
 802   /* Reboot into the new "disk"; this is also a test for the interrupt hooks */
 803   puts("Loading boot sector... ");
 804
 805   memset(&regs, 0, sizeof regs);
 806   // regs.es = 0;
 807   regs.eax.w[0] = 0x0201;       /* Read sector */
 808   regs.ebx.w[0] = 0x7c00;       /* 0000:7C00 */
 809   regs.ecx.w[0] = 1;            /* One sector */
 810   regs.edx.w[0] = geometry->driveno;
 811   syscall(0x13, &regs, &regs);
 812
 813   if ( regs.eflags.l & 1 ) {
 814     puts("MEMDISK: Failed to load new boot sector\n");
 815     die();
 816   }
 817
 818   if ( getcmditem("pause") != CMD_NOTFOUND ) {
 819     puts("press any key to boot... ");
 820     regs.eax.w[0] = 0;
 821     syscall(0x16, &regs, NULL);
 822   }
 823
 824   puts("booting...\n");
 825
 826   /* On return the assembly code will jump to the boot vector */
 827   shdr->esdi = pnp_install_check();
 828   shdr->edx  = geometry->driveno;
 829 }