// Rom layout and bios assembler to C interface. // // Copyright (C) 2008-2012 Kevin O'Connor // Copyright (C) 2002 MandrakeSoft S.A. // // This file may be distributed under the terms of the GNU LGPLv3 license. #include "config.h" // CONFIG_* #include "ioport.h" // PORT_A20 #include "x86.h" // CR0_* #include "hw/cmos.h" // CMOS_RESET_CODE #include "asm-offsets.h" // BREGS_* #include "entryfuncs.S" // ENTRY_* /**************************************************************** * Call trampolines ****************************************************************/ // Place CPU into 32bit mode from 16bit mode. // %edx = return location (in 32bit mode) // Clobbers: ecx, flags, segment registers, cr0, idt/gdt DECLFUNC transition32 .code16gcc transition32: movl %eax, %ecx // Disable irqs (and clear direction flag) cli cld // Disable nmi movl $CMOS_RESET_CODE|NMI_DISABLE_BIT, %eax outb %al, $PORT_CMOS_INDEX inb $PORT_CMOS_DATA, %al // enable a20 inb $PORT_A20, %al orb $A20_ENABLE_BIT, %al outb %al, $PORT_A20 // Set segment descriptors lidtw %cs:pmode_IDT_info lgdtw %cs:rombios32_gdt_48 // Enable protected mode movl %cr0, %eax orl $CR0_PE, %eax movl %eax, %cr0 // start 32bit protected mode code ljmpl $SEG32_MODE32_CS, $(BUILD_BIOS_ADDR + 1f) .code32 1: // init data segments movl $SEG32_MODE32_DS, %eax movw %ax, %ds movw %ax, %es movw %ax, %ss movw %ax, %fs movw %ax, %gs movl %ecx, %eax jmpl *%edx // Place CPU into 16bit mode from 32bit mode. // %edx = return location (in 16bit mode) // Clobbers: ecx, flags, segment registers, cr0, idt/gdt DECLFUNC transition16 .global transition16big transition16: movl %eax, %ecx // restore data segment limits to 0xffff movl $SEG32_MODE16_DS, %eax movw %ax, %ds movw %ax, %es movw %ax, %ss movw %ax, %fs movw %ax, %gs #if CONFIG_DISABLE_A20 // disable a20 inb $PORT_A20, %al andb $~A20_ENABLE_BIT, %al outb %al, $PORT_A20 #endif // Jump to 16bit mode ljmpw $SEG32_MODE16_CS, $1f transition16big: movl %eax, %ecx movl $SEG32_MODE16BIG_DS, %eax movw %ax, %ds movw %ax, %es movw %ax, %ss movw %ax, %fs movw %ax, %gs ljmpw $SEG32_MODE16BIG_CS, $1f .code16gcc 1: // Disable protected mode movl %cr0, %eax andl $~CR0_PE, %eax movl %eax, %cr0 // far jump to flush CPU queue after transition to real mode ljmpw $SEG_BIOS, $2f 2: // restore IDT to normal real-mode defaults lidtw %cs:rmode_IDT_info // Clear segment registers xorw %ax, %ax movw %ax, %fs movw %ax, %gs movw %ax, %es movw %ax, %ds movw %ax, %ss // Assume stack is in segment 0 movl %ecx, %eax jmpl *%edx // Far call a 16bit function from 16bit mode with a specified cpu register state // %es:%eax = address of struct bregs // Clobbers: %e[bcd]x, %e[ds]i, flags DECLFUNC __farcall16 __farcall16: // Save %eax, %ebp pushl %ebp pushl %eax pushl %es // Setup for iretw call pushw %cs pushw $1f // return point pushw %es:BREGS_flags(%eax) // flags pushl %es:BREGS_code(%eax) // CS:IP // Load calling registers. movl %es:BREGS_edi(%eax), %edi movl %es:BREGS_esi(%eax), %esi movl %es:BREGS_ebp(%eax), %ebp movl %es:BREGS_ebx(%eax), %ebx movl %es:BREGS_edx(%eax), %edx movl %es:BREGS_ecx(%eax), %ecx movw %es:BREGS_ds(%eax), %ds pushl %es:BREGS_eax(%eax) movw %es:BREGS_es(%eax), %es popl %eax // Invoke call iretw // XXX - just do a lcalll 1: // Store flags, es, eax pushfw cli cld pushw %es pushl %eax movw 0x08(%esp), %es movl 0x0c(%esp), %eax popl %es:BREGS_eax(%eax) popw %es:BREGS_es(%eax) popw %es:BREGS_flags(%eax) // Store remaining registers movl %edi, %es:BREGS_edi(%eax) movl %esi, %es:BREGS_esi(%eax) movl %ebp, %es:BREGS_ebp(%eax) movl %ebx, %es:BREGS_ebx(%eax) movl %edx, %es:BREGS_edx(%eax) movl %ecx, %es:BREGS_ecx(%eax) movw %ds, %es:BREGS_ds(%eax) movw %ss, %cx movw %cx, %ds // Restore %ds == %ss // Remove %es/%eax, restore %ebp popl %eax popl %eax popl %ebp retl // Call a 16bit SeaBIOS function from SeaBIOS 32bit C code. // %ebx = calling function // Clobbers: %ecx, %edx, flags, segment registers, idt/gdt DECLFUNC __call16 .global __call16big .code32 __call16: movl $1f, %edx jmp transition16 __call16big: movl $1f, %edx jmp transition16big // Make call. .code16gcc 1: calll *%ebx // Return via transition32 movl $(2f + BUILD_BIOS_ADDR), %edx jmp transition32 .code32 2: retl .code16gcc // IRQ trampolines .macro IRQ_TRAMPOLINE num DECLFUNC irq_trampoline_0x\num irq_trampoline_0x\num : int $0x\num lretw .endm IRQ_TRAMPOLINE 02 IRQ_TRAMPOLINE 10 IRQ_TRAMPOLINE 13 IRQ_TRAMPOLINE 15 IRQ_TRAMPOLINE 16 IRQ_TRAMPOLINE 18 IRQ_TRAMPOLINE 19 IRQ_TRAMPOLINE 1c IRQ_TRAMPOLINE 4a /**************************************************************** * Misc. entry points. ****************************************************************/ // Resume (and reboot) entry point - called from entry_post DECLFUNC entry_resume entry_resume: // Disable interrupts cli cld // Use the ExtraStack in low mem. movl $_zonelow_seg, %eax movw %ax, %ds movw %ax, %ss movl $ExtraStack + BUILD_EXTRA_STACK_SIZE, %esp // Call handler. jmp handle_resume // PMM entry point DECLFUNC entry_pmm entry_pmm: pushl %esp // Backup %esp, then clear high bits movzwl %sp, %esp pushfl // Save registers clobbered by C code cli cld pushl %eax pushl %ecx pushl %edx pushw %es pushw %ds movw %ss, %cx // Move %ss to %ds movw %cx, %ds movl $_cfunc32flat_handle_pmm, %eax // Setup: call32(handle_pmm, args, -1) leal 28(%esp), %edx // %edx points to start of args movl $-1, %ecx calll call32 movw %ax, 12(%esp) // Modify %ax:%dx to return %eax shrl $16, %eax movw %ax, 4(%esp) popw %ds // Restore saved registers popw %es popl %edx popl %ecx popl %eax popfl popl %esp lretw // PnP entry points DECLFUNC entry_pnp_real .global entry_pnp_prot entry_pnp_prot: pushl %esp jmp 1f entry_pnp_real: pushl %esp // Backup %esp, then clear high bits movzwl %sp, %esp 1: pushfl // Save registers clobbered by C code cli cld pushl %eax pushl %ecx pushl %edx pushw %es pushw %ds movw %ss, %cx // Move %ss to %ds movw %cx, %ds leal 28(%esp), %eax // %eax points to start of u16 args calll handle_pnp movw %ax, 12(%esp) // Modify %eax to return %ax popw %ds popw %es popl %edx popl %ecx popl %eax popfl popl %esp lretw // APM entry points DECLFUNC entry_apm16 entry_apm16: pushfw // save flags pushl %eax // dummy ENTRY_ARG handle_apm addw $4, %sp // pop dummy popfw // restore flags lretw .code32 DECLFUNC entry_apm32 entry_apm32: pushfl pushl %gs pushl %cs // Move second descriptor after %cs to %gs addl $16, (%esp) popl %gs ENTRY_ARG_ESP _cfunc32seg_handle_apm popl %gs popfl lretl // PCI-BIOS entry points DECLFUNC entry_pcibios32 entry_pcibios32: pushfl pushl %gs // Backup %gs and set %gs=%ds pushl %ds popl %gs ENTRY_ARG_ESP _cfunc32seg_handle_pcibios popl %gs popfl lretl .code16gcc DECLFUNC entry_pcibios16 entry_pcibios16: ENTRY_ARG handle_pcibios iretw // BIOS32 support .code32 DECLFUNC entry_bios32 entry_bios32: pushfl #if CONFIG_PCIBIOS // Check for PCI-BIOS request cmpl $0x49435024, %eax // $PCI jne 1f movl $BUILD_BIOS_ADDR, %ebx movl $BUILD_BIOS_SIZE, %ecx movl $entry_pcibios32, %edx xorb %al, %al jmp 2f #endif // Unknown request 1: movb $0x80, %al // Return to caller 2: popfl lretl // 32bit elf entry point EXPORTFUNC entry_elf entry_elf: cli cld lidtl (BUILD_BIOS_ADDR + pmode_IDT_info) lgdtl (BUILD_BIOS_ADDR + rombios32_gdt_48) movl $SEG32_MODE32_DS, %eax movw %ax, %ds movw %ax, %es movw %ax, %fs movw %ax, %gs movw %ax, %ss movl $BUILD_STACK_ADDR, %esp ljmpl $SEG32_MODE32_CS, $_cfunc32flat_handle_post .code16gcc // UEFI Compatibility Support Module (CSM) entry point EXPORTFUNC entry_csm entry_csm: // Backup register state pushfw cli cld pushl %eax // dummy PUSHBREGS // Backup stack location and convert to a "flat pointer" movl %ss, %eax movw %ax, BREGS_code+2(%esp) // Store %ss in bregs->code.seg shll $4, %eax addl %esp, %eax // Change to BUILD_STACK_ADDR stack xorl %ebx, %ebx movw %bx, %ss movl $BUILD_STACK_ADDR, %esp // Jump to 32bit mode and call handle_csm(bregs) movl $_cfunc32flat_handle_csm, %edx jmp transition32 DECLFUNC __csm_return .code32 __csm_return: movl $1f, %edx jmp transition16big .code16gcc // Switch back to original stack 1: movzwl BREGS_code+2(%eax), %edx movl %edx, %ecx shll $4, %ecx subl %ecx, %eax movl %edx, %ss movl %eax, %esp // Restore register state and return. POPBREGS addw $4, %sp // pop dummy popfw lretw /**************************************************************** * Interrupt entry points ****************************************************************/ // Main entry point for interrupts handled on extra stack DECLFUNC irqentry_extrastack irqentry_extrastack: cli cld pushw %ds // Set %ds:%eax to space on ExtraStack pushl %eax movl $_zonelow_seg, %eax movl %eax, %ds movl StackPos, %eax subl $24, %eax popl 0(%eax) // Backup %eax, %ds, %es, %ecx, %edx popw 4(%eax) movw %es, 6(%eax) movl %ecx, 8(%eax) popl %ecx movl %edx, 12(%eax) movl %esp, 16(%eax) movzwl %sp, %esp movw %ss, 20(%eax) movw %ds, %dx // Setup %ss/%esp and call function movw %dx, %ss movl %eax, %esp calll *%ecx movl %esp, %eax // Restore registers and return movw 20(%eax), %ss movl 16(%eax), %esp movl 12(%eax), %edx movl 8(%eax), %ecx movw 6(%eax), %es pushw 4(%eax) pushl 0(%eax) popl %eax popw %ds iretw // Main entry point for interrupts handled on extra stack DECLFUNC irqentry_arg_extrastack irqentry_arg_extrastack: cli cld pushw %ds // Set %ds:%eax to space on ExtraStack pushl %eax movl $_zonelow_seg, %eax movl %eax, %ds movl StackPos, %eax subl $BREGS_size+8, %eax popl BREGS_eax(%eax) // Backup registers popw BREGS_ds(%eax) movl %edi, BREGS_edi(%eax) movl %esi, BREGS_esi(%eax) movl %ebp, BREGS_ebp(%eax) movl %ebx, BREGS_ebx(%eax) movl %edx, BREGS_edx(%eax) movl %ecx, BREGS_ecx(%eax) popl %ecx movw %es, BREGS_es(%eax) movl %esp, BREGS_size+0(%eax) movzwl %sp, %esp movw %ss, BREGS_size+4(%eax) movl (%esp), %edx movl %edx, BREGS_code(%eax) movw 4(%esp), %dx movw %dx, BREGS_flags(%eax) movw %ds, %dx // Setup %ss/%esp and call function movw %dx, %ss movl %eax, %esp calll *%ecx movl %esp, %eax // Restore registers and return movw BREGS_size+4(%eax), %ss movl BREGS_size+0(%eax), %esp popl %edx popw %dx pushw BREGS_flags(%eax) pushl BREGS_code(%eax) movl BREGS_edi(%eax), %edi movl BREGS_esi(%eax), %esi movl BREGS_ebp(%eax), %ebp movl BREGS_ebx(%eax), %ebx movl BREGS_edx(%eax), %edx movl BREGS_ecx(%eax), %ecx movw BREGS_es(%eax), %es pushw BREGS_ds(%eax) pushl BREGS_eax(%eax) popl %eax popw %ds iretw // Main entry point for interrupts with args DECLFUNC irqentryarg irqentryarg: ENTRY_ARG_ST iretw // Define an entry point for hardware interrupts. .macro IRQ_ENTRY num .global entry_\num entry_\num : pushl $ handle_\num jmp irqentry_extrastack .endm .macro DECL_IRQ_ENTRY num DECLFUNC entry_\num IRQ_ENTRY \num .endm // Define an entry point for an interrupt (can read/modify args). .macro IRQ_ENTRY_ARG num .global entry_\num entry_\num : pushl $ handle_\num #if CONFIG_ENTRY_EXTRASTACK jmp irqentry_arg_extrastack #else jmp irqentryarg #endif .endm .macro DECL_IRQ_ENTRY_ARG num DECLFUNC entry_\num IRQ_ENTRY_ARG \num .endm // Various entry points (that don't require a fixed location). DECL_IRQ_ENTRY_ARG 13 DECL_IRQ_ENTRY 76 DECL_IRQ_ENTRY 70 DECL_IRQ_ENTRY 74 DECL_IRQ_ENTRY 75 DECL_IRQ_ENTRY hwpic1 DECL_IRQ_ENTRY hwpic2 // int 18/19 are special - they reset stack and call into 32bit mode. DECLFUNC entry_19 entry_19: ENTRY_INTO32 _cfunc32flat_handle_19 DECLFUNC entry_18 entry_18: ENTRY_INTO32 _cfunc32flat_handle_18 /**************************************************************** * Fixed position entry points ****************************************************************/ // Specify a location in the fixed part of bios area. .macro ORG addr .section .fixedaddr.\addr .endm ORG 0xe05b entry_post: cmpl $0, %cs:HaveRunPost // Check for resume/reboot jnz entry_resume ENTRY_INTO32 _cfunc32flat_handle_post // Normal entry point ORG 0xe2c3 IRQ_ENTRY 02 ORG 0xe3fe .global entry_13_official entry_13_official: jmp entry_13 // 0xe401 - OldFDPT in disk.c ORG 0xe6f2 .global entry_19_official entry_19_official: jmp entry_19 // 0xe6f5 - BIOS_CONFIG_TABLE in misc.c // 0xe729 - BaudTable in serial.c ORG 0xe739 IRQ_ENTRY_ARG 14 ORG 0xe82e IRQ_ENTRY_ARG 16 ORG 0xe987 IRQ_ENTRY 09 ORG 0xec59 IRQ_ENTRY_ARG 40 ORG 0xef57 IRQ_ENTRY 0e // 0xefc7 - diskette_param_table in floppy.c ORG 0xefd2 IRQ_ENTRY_ARG 17 ORG 0xf045 entry_10_0x0f: // XXX - INT 10 Functions 0-Fh Entry Point iretw ORG 0xf065 IRQ_ENTRY_ARG 10 // 0xf0a4 - VideoParams in misc.c ORG 0xf841 IRQ_ENTRY_ARG 12 ORG 0xf84d IRQ_ENTRY_ARG 11 ORG 0xf859 IRQ_ENTRY_ARG 15 // 0xfa6e - vgafont8 in font.c ORG 0xfe6e .global entry_1a_official entry_1a_official: cmpb $0xb1, %ah je entry_pcibios16 // PCIBIOS calls can be in protected mode IRQ_ENTRY_ARG 1a ORG 0xfea5 IRQ_ENTRY 08 // 0xfef3 - InitVectors in misc.c // 0xff00 - BiosCopyright in misc.c ORG 0xff53 .global entry_iret_official entry_iret_official: iretw ORG 0xff54 IRQ_ENTRY_ARG 05 ORG 0xfff0 // Power-up Entry Point .global reset_vector reset_vector: ljmpw $SEG_BIOS, $entry_post // 0xfff5 - BiosDate in misc.c // 0xfffe - BiosModelId in misc.c // 0xffff - BiosChecksum in misc.c .end