diff options
Diffstat (limited to 'src/boot.c')
| -rw-r--r-- | src/boot.c | 214 |
1 files changed, 139 insertions, 75 deletions
@@ -5,114 +5,178 @@ // // This file may be distributed under the terms of the GNU GPLv3 license. -#include "types.h" // VISIBLE #include "util.h" // irq_enable #include "biosvar.h" // struct bregs -#include "farptr.h" // SET_SEG +#include "config.h" // CONFIG_* +#include "cmos.h" // inb_cmos -static inline void -__call_irq(u8 nr) -{ - asm volatile("int %0" : : "N" (nr)); -} +//-------------------------------------------------------------------------- +// print_boot_device +// displays the boot device +//-------------------------------------------------------------------------- -static inline u32 -call_irq(u8 nr, struct bregs *callregs) +static const char drivetypes[][10]={ + "", "Floppy","Hard Disk","CD-Rom", "Network" +}; + +static void +print_boot_device(u16 type) { - u32 flags; - asm volatile( - // Save current registers - "pushal\n" - // Pull in calling registers. - "movl 0x04(%%eax), %%edi\n" - "movl 0x08(%%eax), %%esi\n" - "movl 0x0c(%%eax), %%ebp\n" - "movl 0x14(%%eax), %%ebx\n" - "movl 0x18(%%eax), %%edx\n" - "movl 0x1c(%%eax), %%ecx\n" - "movl 0x20(%%eax), %%eax\n" - // Invoke interrupt - "int %1\n" - // Restore registers - "popal\n" - // Exract flags - "pushfw\n" - "popl %%eax\n" - : "=a" (flags): "N" (nr), "a" (callregs), "m" (*callregs)); - return flags; + /* NIC appears as type 0x80 */ + if (type == IPL_TYPE_BEV) + type = 0x4; + if (type == 0 || type > 0x4) + BX_PANIC("Bad drive type\n"); + printf("Booting from %s...\n", drivetypes[type]); } +//-------------------------------------------------------------------------- +// print_boot_failure +// displays the reason why boot failed +//-------------------------------------------------------------------------- static void -print_boot_failure() +print_boot_failure(u16 type, u8 reason) { - bprintf(0, "Boot failed\n"); + if (type == 0 || type > 0x3) + BX_PANIC("Bad drive type\n"); + + printf("Boot from %s failed", drivetypes[type]); + if (type < 4) { + /* Report the reason too */ + if (reason==0) + printf(": not a bootable disk"); + else + printf(": could not read the boot disk"); + } + printf("\n"); } static void -try_boot() +try_boot(u16 seq_nr) { - // XXX - assume floppy - u16 bootseg = 0x07c0; + SET_IPL(sequence, seq_nr); + u16 bootseg; u8 bootdrv = 0; + u16 bootdev, bootip; + + if (CONFIG_ELTORITO_BOOT) { + bootdev = inb_cmos(CMOS_BIOS_BOOTFLAG2); + bootdev |= ((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0xf0) << 4); + bootdev >>= 4 * seq_nr; + bootdev &= 0xf; + if (bootdev == 0) + BX_PANIC("No bootable device.\n"); + + /* Translate from CMOS runes to an IPL table offset by subtracting 1 */ + bootdev -= 1; + } else { + if (seq_nr ==2) + BX_PANIC("No more boot devices."); + if (!!(inb_cmos(CMOS_BIOS_CONFIG) & 0x20) ^ (seq_nr == 1)) + /* Boot from floppy if the bit is set or it's the second boot */ + bootdev = 0x00; + else + bootdev = 0x01; + } + + if (bootdev >= GET_IPL(count)) { + BX_INFO("Invalid boot device (0x%x)\n", bootdev); + return; + } + u16 type = GET_IPL(table[bootdev].type); + + /* Do the loading, and set up vector as a far pointer to the boot + * address, and bootdrv as the boot drive */ + print_boot_device(type); - // Read sector struct bregs cr; - memset(&cr, 0, sizeof(cr)); - cr.dl = bootdrv; - SET_SEG(ES, bootseg); - cr.bx = 0; - cr.ah = 2; - cr.al = 1; - cr.ch = 0; - cr.cl = 1; - cr.dh = 0; - u32 status = call_irq(0x13, &cr); - - if (status & F_CF) { - print_boot_failure(); + switch(type) { + case IPL_TYPE_FLOPPY: /* FDD */ + case IPL_TYPE_HARDDISK: /* HDD */ + + bootdrv = (type == IPL_TYPE_HARDDISK) ? 0x80 : 0x00; + bootseg = 0x07c0; + + // Read sector + memset(&cr, 0, sizeof(cr)); + cr.dl = bootdrv; + cr.es = bootseg; + cr.ah = 2; + cr.al = 1; + cr.cl = 1; + call16_int(0x13, &cr); + + if (cr.flags & F_CF) { + print_boot_failure(type, 1); + return; + } + + /* Always check the signature on a HDD boot sector; on FDD, + * only do the check if the CMOS doesn't tell us to skip it */ + if ((type != IPL_TYPE_FLOPPY) + || !((inb_cmos(CMOS_BIOS_BOOTFLAG1) & 0x01))) { + if (GET_FARVAR(bootseg, *(u16*)0x1fe) != 0xaa55) { + print_boot_failure(type, 0); + return; + } + } + + /* Canonicalize bootseg:bootip */ + bootip = (bootseg & 0x0fff) << 4; + bootseg &= 0xf000; + break; + case IPL_TYPE_CDROM: /* CD-ROM */ + // XXX return; + break; + case IPL_TYPE_BEV: { + /* Expansion ROM with a Bootstrap Entry Vector (a far + * pointer) */ + u32 vector = GET_IPL(table[bootdev].vector); + bootseg = vector >> 16; + bootip = vector & 0xffff; + break; } + default: + return; + } + + memset(&cr, 0, sizeof(cr)); + cr.ip = bootip; + cr.cs = bootseg; + // Set the magic number in ax and the boot drive in dl. + cr.dl = bootdrv; + cr.ax = 0xaa55; + call16(&cr); - u16 bootip = (bootseg & 0x0fff) << 4; - bootseg &= 0xf000; - - u32 segoff = (bootseg << 16) | bootip; - asm volatile ( - "pushf\n" - "pushl %0\n" - "movb %b1, %%dl\n" - // Set the magic number in ax and the boot drive in dl. - "movw $0xaa55, %%ax\n" - // Zero some of the other registers. - "xorw %%bx, %%bx\n" - "movw %%bx, %%ds\n" - "movw %%bx, %%es\n" - "movw %%bx, %%bp\n" - // Go! - "iretw\n" - : : "r" (segoff), "ri" (bootdrv)); + // Boot failed: invoke the boot recovery function + memset(&cr, 0, sizeof(cr)); + call16_int(0x18, &cr); } // Boot Failure recovery: try the next device. void VISIBLE -handle_18(struct bregs *regs) +handle_18() { - debug_enter(regs); - try_boot(); + debug_enter(NULL); + u16 seq = GET_IPL(sequence) + 1; + try_boot(seq); } // INT 19h Boot Load Service Entry Point void VISIBLE -handle_19(struct bregs *regs) +handle_19() { - debug_enter(regs); - try_boot(); + debug_enter(NULL); + try_boot(0); } -// Callback from 32bit entry - start boot process +// Called from 32bit code - start boot process void VISIBLE begin_boot() { irq_enable(); - __call_irq(0x19); + struct bregs br; + memset(&br, 0, sizeof(br)); + call16_int(0x19, &br); } |