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Diffstat (limited to 'src/VBox/Devices/PC/BIOS/boot.c')
| -rw-r--r-- | src/VBox/Devices/PC/BIOS/boot.c | 365 |
1 files changed, 365 insertions, 0 deletions
diff --git a/src/VBox/Devices/PC/BIOS/boot.c b/src/VBox/Devices/PC/BIOS/boot.c new file mode 100644 index 00000000..8834aa30 --- /dev/null +++ b/src/VBox/Devices/PC/BIOS/boot.c @@ -0,0 +1,365 @@ +/* $Id: boot.c $ */ +/** @file + * PC BIOS - ??? + */ + +/* + * Copyright (C) 2006-2023 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * 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, in version 3 of the + * License. + * + * 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, see <https://www.gnu.org/licenses>. + * + * SPDX-License-Identifier: GPL-3.0-only + * -------------------------------------------------------------------- + * + * This code is based on: + * + * ROM BIOS for use with Bochs/Plex86/QEMU emulation environment + * + * Copyright (C) 2002 MandrakeSoft S.A. + * + * MandrakeSoft S.A. + * 43, rue d'Aboukir + * 75002 Paris - France + * http://www.linux-mandrake.com/ + * http://www.mandrakesoft.com/ + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + */ + +/* + * Oracle LGPL Disclaimer: For the avoidance of doubt, except that if any license choice + * other than GPL or LGPL is available it will apply instead, Oracle elects to use only + * the Lesser General Public License version 2.1 (LGPLv2) at this time for any software where + * a choice of LGPL license versions is made available with the language indicating + * that LGPLv2 or any later version may be used, or where a choice of which version + * of the LGPL is applied is otherwise unspecified. + */ + + +#include <stdint.h> +#include <string.h> +#include "inlines.h" +#include "biosint.h" +#include "ebda.h" + +/* Sanity check the LAN boot segment definition. */ +#if VBOX_LANBOOT_SEG < 0xA000 +#error VBOX_LANBOOT_SEG incorrect! +#endif + +/* PnP header used with LAN boot ROMs. */ +typedef struct { + uint32_t sig; + uint8_t revision; + uint8_t length; + uint16_t next_s; + uint8_t pad1; + uint8_t checksum; + uint32_t dev_id; + uint16_t mfg_string; + uint16_t prod_string; + uint8_t base_class; + uint8_t subclass; + uint8_t interface; + uint8_t dev_ind; + uint16_t boot_code; + uint16_t dv; + uint16_t bev; + uint16_t pad2; + uint16_t sriv; +} pnp_exp_t; + + +int read_boot_sec(uint8_t bootdrv, uint16_t segment); +#pragma aux read_boot_sec = \ + "mov ax,0201h" \ + "mov dh,0" \ + "mov cx,1" \ + "xor bx,bx" \ + "int 13h" \ + "mov ax,0" \ + "sbb ax,0" \ + parm [dl] [es] modify [ax bx cx dx]; + +//-------------------------------------------------------------------------- +// print_boot_device +// displays the boot device +//-------------------------------------------------------------------------- + +static const char drivetypes[][10]={"Floppy","Hard Disk","CD-ROM","LAN"}; + +/// @todo pass inputs as bit flags rather than bytes? +void print_boot_device(uint8_t cdboot, uint8_t lanboot, uint8_t drive) +{ + int i; + + // cdboot contains 0 if lan/floppy/harddisk, 1 otherwise + // lanboot contains 0 if floppy/harddisk, 1 otherwise + // drive contains real/emulated boot drive + + if(cdboot)i=2; // CD-Rom + else if(lanboot)i=3; // LAN + else if((drive&0x0080)==0x00)i=0; // Floppy + else if((drive&0x0080)==0x80)i=1; // Hard drive + else return; + + BX_INFO("Booting from %s...\n",drivetypes[i]); +} + +//-------------------------------------------------------------------------- +// print_boot_failure +// displays the reason why boot failed +//-------------------------------------------------------------------------- +/// @todo pass inputs as bit flags rather than bytes? +void print_boot_failure(uint8_t cdboot, uint8_t lanboot, uint8_t drive, + uint8_t reason, uint8_t lastdrive) +{ + uint16_t drivenum = drive&0x7f; + + // cdboot: 1 if boot from cd, 0 otherwise + // lanboot: 1 if boot from lan, 0 otherwise + // drive : drive number + // reason: 0 signature check failed, 1 read error + // lastdrive: 1 boot drive is the last one in boot sequence + + if (cdboot) + BX_INFO("Boot from %s failed\n",drivetypes[2]); + else if (lanboot) + BX_INFO("Boot from %s failed\n",drivetypes[3]); + else if (drive & 0x80) + BX_INFO("Boot from %s %d failed\n", drivetypes[1],drivenum); + else + BX_INFO("Boot from %s %d failed\n", drivetypes[0],drivenum); + + if (lastdrive==1) { + if (reason==0) + BX_INFO_CON("No bootable medium found!\n"); + else + BX_INFO_CON("Could not read from the boot medium!\n"); + BX_INFO_CON("Please insert a bootable medium and reboot.\n"); + } +} + +//-------------------------------------------------------------------------- +// print_cdromboot_failure +// displays the reason why boot failed +//-------------------------------------------------------------------------- +void print_cdromboot_failure(uint16_t code) +{ + BX_INFO("CDROM boot failure code : %04x\n",code); + return; +} + +// returns bootsegment in ax, drive in bl +uint32_t BIOSCALL int19_function(uint8_t bseqnr) +{ + /// @todo common code for getting the EBDA segment + uint16_t ebda_seg=read_word(0x0040,0x000E); + uint16_t bootseq; + uint8_t bootdrv; + uint8_t bootcd; + uint8_t bootlan; + uint8_t bootchk; + uint16_t bootseg; + uint16_t status; + uint8_t lastdrive=0; + + // if BX_ELTORITO_BOOT is not defined, old behavior + // check bit 5 in CMOS reg 0x2d. load either 0x00 or 0x80 into DL + // in preparation for the initial INT 13h (0=floppy A:, 0x80=C:) + // 0: system boot sequence, first drive C: then A: + // 1: system boot sequence, first drive A: then C: + // else BX_ELTORITO_BOOT is defined + // CMOS regs 0x3D and 0x38 contain the boot sequence: + // CMOS reg 0x3D & 0x0f : 1st boot device + // CMOS reg 0x3D & 0xf0 : 2nd boot device + // CMOS reg 0x38 & 0xf0 : 3rd boot device + // CMOS reg 0x3C & 0x0f : 4th boot device + // boot device codes: + // 0x00 : not defined + // 0x01 : first floppy + // 0x02 : first harddrive + // 0x03 : first cdrom + // 0x04 : local area network + // else : boot failure + + // Get the boot sequence +#if BX_ELTORITO_BOOT + bootseq=inb_cmos(0x3d); + bootseq|=((inb_cmos(0x38) & 0xf0) << 4); + bootseq|=((inb_cmos(0x3c) & 0x0f) << 12); + if (read_byte(ebda_seg, (uint16_t)&EbdaData->uForceBootDevice)) + bootseq = read_byte(ebda_seg, (uint16_t)&EbdaData->uForceBootDevice); + /* Boot delay hack. */ + if (bseqnr == 1) + delay_boot((inb_cmos(0x3c) & 0xf0) >> 4); /* Implemented in logo.c */ + + if (bseqnr==2) bootseq >>= 4; + if (bseqnr==3) bootseq >>= 8; + if (bseqnr==4) bootseq >>= 12; + if (bootseq<0x10) lastdrive = 1; + bootdrv=0x00; bootcd=0; + bootlan=0; + BX_INFO("Boot : bseqnr=%d, bootseq=%x\r\n",bseqnr, bootseq); + + switch(bootseq & 0x0f) { + case 0x01: + bootdrv=0x00; + bootcd=0; + break; + case 0x02: + { + // Get the Boot drive. + uint8_t boot_drive = read_byte(ebda_seg, (uint16_t)&EbdaData->uForceBootDrive); + + bootdrv = boot_drive + 0x80; + bootcd=0; + break; + } + case 0x03: + bootdrv=0x00; + bootcd=1; + break; + case 0x04: bootlan=1; break; + default: return 0x00000000; + } +#else + bootseq=inb_cmos(0x2d); + + if (bseqnr==2) { + bootseq ^= 0x20; + lastdrive = 1; + } + bootdrv=0x00; bootcd=0; + if((bootseq&0x20)==0) bootdrv=0x80; +#endif // BX_ELTORITO_BOOT + +#if BX_ELTORITO_BOOT + // We have to boot from cd + if (bootcd != 0) { + status = cdrom_boot(); + + // If failure + if ( (status & 0x00ff) !=0 ) { + print_cdromboot_failure(status); + print_boot_failure(bootcd, bootlan, bootdrv, 1, lastdrive); + return 0x00000000; + } + + bootseg = read_word(ebda_seg,(uint16_t)&EbdaData->cdemu.load_segment); + bootdrv = (uint8_t)(status>>8); + } + +#endif // BX_ELTORITO_BOOT + + // Check for boot from LAN first + if (bootlan == 1) { + uint8_t __far *fplan; + + fplan = MK_FP(VBOX_LANBOOT_SEG, 0); + if (*(uint16_t __far *)fplan == 0xaa55) { + pnp_exp_t __far *pnps; + uint32_t manuf; + void (__far *netboot_entry)(void); + + // This is NOT a generic PnP implementation, but an Etherboot-specific hack. + pnps = (void __far *)(fplan + *(uint16_t __far *)(fplan + 0x1a)); + if (pnps->sig == 0x506e5024/* '$PnP' */) { + // Found PnP signature + manuf = *(uint32_t __far *)(fplan + pnps->mfg_string); + if (manuf == 0x65687445/* 'Ethe' */) { + // Found Etherboot ROM + print_boot_device(bootcd, bootlan, bootdrv); + netboot_entry = (void __far *)(fplan + 6); + netboot_entry(); + } + else + { + //Found Normal Pnp ROM + print_boot_device(bootcd, bootlan, bootdrv); + int_enable(); /* Disabled as we were invoked via INT instruction. */ + netboot_entry = (void __far *)(fplan + pnps->bev); + netboot_entry(); + } + } + } + + // boot from LAN will not return if successful. + print_boot_failure(bootcd, bootlan, bootdrv, 1, lastdrive); + return 0x00000000; + } + + // We have to boot from harddisk or floppy + if (bootcd == 0 && bootlan == 0) { + bootseg=0x07c0; + + status = read_boot_sec(bootdrv,bootseg); + if (status != 0) { + print_boot_failure(bootcd, bootlan, bootdrv, 1, lastdrive); + return 0x00000000; + } + } + + // There is *no* requirement whatsoever for a valid floppy boot sector + // to have a 55AAh signature. UNIX boot floppies typically have no such + // signature. In general, it is impossible to tell a valid bootsector + // from an invalid one. + // NB: It is somewhat common for failed OS installs to have the + // 0x55AA signature and a valid partition table but zeros in the + // rest of the boot sector. We do a quick check by comparing the first + // and third word of boot sector; if identical, the boot sector is + // extremely unlikely to be valid. + if (bootdrv != 0) bootchk = 0; + else bootchk = 1; /* disable 0x55AA signature check on drive A: */ + +#if BX_ELTORITO_BOOT + // if boot from cd, no signature check + if (bootcd != 0) + bootchk = 1; +#endif // BX_ELTORITO_BOOT + + if (read_word(bootseg,0) == read_word(bootseg,4) + || (bootchk == 0 && read_word(bootseg,0x1fe) != 0xaa55)) + { + print_boot_failure(bootcd, bootlan, bootdrv, 0, lastdrive); + return 0x00000000; + } + +#if BX_ELTORITO_BOOT + // Print out the boot string + print_boot_device(bootcd, bootlan, bootdrv); +#else // BX_ELTORITO_BOOT + print_boot_device(0, bootlan, bootdrv); +#endif // BX_ELTORITO_BOOT + + // return the boot segment + return (((uint32_t)bootdrv) << 16) + bootseg; +} + |