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// Rom layout and bios assembler to C interface.
//
// Copyright (C) 2008-2012 Kevin O'Connor <kevin@koconnor.net>
// Copyright (C) 2002 MandrakeSoft S.A.
//
// This file may be distributed under the terms of the GNU LGPLv3 license.
#include "asm-offsets.h" // BREGS_*
#include "config.h" // CONFIG_*
#include "entryfuncs.S" // ENTRY_*
#include "hw/ps2port.h" // PORT_A20
#include "hw/rtc.h" // CMOS_RESET_CODE
#include "x86.h" // CR0_*
/****************************************************************
* 16bit / 32bit 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
// Call a 16bit SeaBIOS function from SeaBIOS 32bit C code.
// %ecx = calling function
// Clobbers: %ecx, %edx, flags, segment registers, idt/gdt
DECLFUNC __call16
.global __call16big
.code32
__call16:
pushl %edx
pushl %ecx
movl $1f, %edx
jmp transition16
__call16big:
pushl %edx
pushl %ecx
movl $1f, %edx
jmp transition16big
// Make call.
.code16gcc
1: popl %ecx
popl %edx
calll *%ecx
// Return via transition32
movl $(2f + BUILD_BIOS_ADDR), %edx
jmp transition32
.code32
2: retl
/****************************************************************
* External calling trampolines
****************************************************************/
// Far call a 16bit function from 16bit mode with a specified cpu register state
// %eax = address of struct bregs, %edx = segment of struct bregs
// Clobbers: %e[bc]x, %e[ds]i, flags
.code16gcc
DECLFUNC __farcall16
__farcall16:
// Save %edx/%eax, %ebp
pushl %ebp
pushl %eax
pushl %edx
// Setup for iretw call
movl %edx, %ds
pushw %cs
pushw $1f // return point
pushw BREGS_flags(%eax) // flags
pushl BREGS_code(%eax) // CS:IP
// Load calling registers.
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
pushl BREGS_eax(%eax)
movw BREGS_ds(%eax), %ds
popl %eax
// Invoke call
iretw // XXX - just do a lcalll
1:
// Store flags, es, eax
pushfw
cli
cld
pushw %ds
pushl %eax
movw 0x08(%esp), %ds
movl 0x0c(%esp), %eax
popl BREGS_eax(%eax)
popw BREGS_es(%eax)
popw BREGS_flags(%eax)
// Store remaining registers
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)
movw %es, BREGS_ds(%eax)
movw %ss, %cx
movw %cx, %ds // Restore %ds == %ss
// Remove %edx/%eax, restore %ebp
popl %edx
popl %eax
popl %ebp
retl
// 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