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#------------------------------------------------------------------------------
#*
#* Copyright 2006, Intel Corporation
#* All rights reserved. This program and the accompanying materials
#* are licensed and made available under the terms and conditions of the BSD License
#* which accompanies this distribution. The full text of the license may be found at
#* http://opensource.org/licenses/bsd-license.php
#*
#* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
#* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#*
#* efi32.asm
#*
#* Abstract:
#*
#------------------------------------------------------------------------------
##############################################################################
# Now in 32-bit protected mode.
##############################################################################
.org 0x21000
.global _start
_start:
.equ DEFAULT_HANDLER_SIZE, INT1 - INT0
.macro jmpCommonIdtEntry
# jmp commonIdtEntry - this must be hand coded to keep the assembler from
# using a 8 bit reletive jump when the entries are
# within 255 bytes of the common entry. This must
# be done to maintain the consistency of the size
# of entry points...
.byte 0xe9 # jmp 16 bit relative
.long commonIdtEntry - . - 4 # offset to jump to
.endm
Start:
movw %ax, %ds
movw %ax, %es
movw %ax, %fs
movw %ax, %gs
movw %ax, %ss
movl $0x001ffff0, %esp
call ClearScreen
# Populate IDT with meaningful offsets for exception handlers...
sidt Idtr
movl Halt, %eax
movl %eax, %ebx # use bx to copy 15..0 to descriptors
shrl $16, %eax # use ax to copy 31..16 to descriptors
movl $0x78, %ecx # 78h IDT entries to initialize with unique entry points (exceptions)
movl (Idtr + 2), %esi
movl (%esi), %edi
LOOP_1: # loop through all IDT entries exception handlers and initialize to default handler
movw %bx, (%edi) # write bits 15..0 of offset
movw $0x20, 2(%edi) # SYS_CODE_SEL from GDT
movw $(0x0e00 | 0x8000), 4(%edi) # type = 386 interrupt gate, present
movw %ax, 6(%edi) # write bits 31..16 of offset
addl $8, %edi # move up to next descriptor
addw DEFAULT_HANDLER_SIZE, %bx # move to next entry point
loopl LOOP_1 # loop back through again until all descriptors are initialized
## at this point edi contains the offset of the descriptor for INT 20
## and bx contains the low 16 bits of the offset of the default handler
## so initialize all the rest of the descriptors with these two values...
# mov ecx, 101 ; there are 100 descriptors left (INT 20 (14h) - INT 119 (77h)
#@@: ; loop through all IDT entries exception handlers and initialize to default handler
# mov word ptr [edi], bx ; write bits 15..0 of offset
# mov word ptr [edi+2], 20h ; SYS_CODE_SEL from GDT
# mov word ptr [edi+4], 0e00h OR 8000h ; type = 386 interrupt gate, present
# mov word ptr [edi+6], ax ; write bits 31..16 of offset
# add edi, 8 ; move up to next descriptor
# loop @b ; loop back through again until all descriptors are initialized
## DUMP location of IDT and several of the descriptors
# mov ecx, 8
# mov eax, [offset Idtr + 2]
# mov eax, [eax]
# mov edi, 0b8000h
# call PrintDword
# mov esi, eax
# mov edi, 0b80a0h
# jmp OuterLoop
##
## just for fun, let's do a software interrupt to see if we correctly land in the exception handler...
# mov eax, 011111111h
# mov ebx, 022222222h
# mov ecx, 033333333h
# mov edx, 044444444h
# mov ebp, 055555555h
# mov esi, 066666666h
# mov edi, 077777777h
# push 011111111h
# push 022222222h
# push 033333333h
# int 119
movl $0x22000, %esi # esi = 22000
movl 0x14(%esi), %eax # eax = [22014]
addl %eax, %esi # esi = 22000 + [22014] = Base of EFILDR.C
movl 0x3c(%esi), %ebp # ebp = [22000 + [22014] + 3c] = NT Image Header for EFILDR.C
addl %esi, %ebp
movl 0x34(%ebp), %edi # edi = [[22000 + [22014] + 3c] + 30] = ImageBase
movl 0x28(%ebp), %eax # eax = [[22000 + [22014] + 3c] + 24] = EntryPoint
addl %edi, %eax # eax = ImageBase + EntryPoint
movl %eax, EfiLdrOffset # Modify far jump instruction for correct entry point
movw 6(%ebp), %bx # bx = Number of sections
xorl %eax, %eax
movw 0x14(%ebp), %ax # ax = Optional Header Size
addl %eax, %ebp
addl $0x18, %ebp # ebp = Start of 1st Section
SectionLoop:
pushl %esi # Save Base of EFILDR.C
pushl %edi # Save ImageBase
addl 0x14(%ebp), %esi # esi = Base of EFILDR.C + PointerToRawData
addl 0x0c(%ebp), %edi # edi = ImageBase + VirtualAddress
movl 0x10(%ebp), %ecx # ecs = SizeOfRawData
cld
shrl $2, %ecx
rep
movsl
popl %edi # Restore ImageBase
popl %esi # Restore Base of EFILDR.C
addw $0x28, %bp # ebp = ebp + 028h = Pointer to next section record
decw %bx
cmpw $0, %bx
jne SectionLoop
movzwl (Idtr), %eax # get size of IDT
incl %eax
addl (Idtr + 2), %eax # add to base of IDT to get location of memory map...
pushl %eax # push memory map location on stack for call to EFILDR...
pushl %eax # push return address (useless, just for stack balance)
.byte 0xb8
EfiLdrOffset:
.long 0x00401000 # Offset of EFILDR
# mov eax, 401000h
pushl %eax
ret
# db "**** DEFAULT IDT ENTRY ***",0
.align 0x2
Halt:
INT0:
pushl $0x0 # push error code place holder on the stack
pushl $0x0
jmpCommonIdtEntry
# db 0e9h ; jmp 16 bit reletive
# dd commonIdtEntry - $ - 4 ; offset to jump to
INT1:
pushl $0x0 # push error code place holder on the stack
pushl $0x1
jmpCommonIdtEntry
INT2:
pushl $0x0 # push error code place holder on the stack
pushl $0x2
jmpCommonIdtEntry
INT3:
pushl $0x0 # push error code place holder on the stack
pushl $0x3
jmpCommonIdtEntry
INT4:
pushl $0x0 # push error code place holder on the stack
pushl $0x4
jmpCommonIdtEntry
INT5:
pushl $0x0 # push error code place holder on the stack
pushl $0x5
jmpCommonIdtEntry
INT6:
pushl $0x0 # push error code place holder on the stack
pushl $0x6
jmpCommonIdtEntry
INT7:
pushl $0x0 # push error code place holder on the stack
pushl $0x7
jmpCommonIdtEntry
INT8:
# Double fault causes an error code to be pushed so no phony push necessary
nop
nop
pushl $0x8
jmpCommonIdtEntry
INT9:
pushl $0x0 # push error code place holder on the stack
pushl $0x9
jmpCommonIdtEntry
INT10:
# Invalid TSS causes an error code to be pushed so no phony push necessary
nop
nop
pushl $10
jmpCommonIdtEntry
INT11:
# Segment Not Present causes an error code to be pushed so no phony push necessary
nop
nop
pushl $11
jmpCommonIdtEntry
INT12:
# Stack fault causes an error code to be pushed so no phony push necessary
nop
nop
pushl $12
jmpCommonIdtEntry
INT13:
# GP fault causes an error code to be pushed so no phony push necessary
nop
nop
pushl $13
jmpCommonIdtEntry
INT14:
# Page fault causes an error code to be pushed so no phony push necessary
nop
nop
pushl $14
jmpCommonIdtEntry
INT15:
pushl $0x0 # push error code place holder on the stack
pushl $15
jmpCommonIdtEntry
INT16:
pushl $0x0 # push error code place holder on the stack
pushl $16
jmpCommonIdtEntry
INT17:
# Alignment check causes an error code to be pushed so no phony push necessary
nop
nop
pushl $17
jmpCommonIdtEntry
INT18:
pushl $0x0 # push error code place holder on the stack
pushl $18
jmpCommonIdtEntry
INT19:
pushl $0x0 # push error code place holder on the stack
pushl $19
jmpCommonIdtEntry
INTUnknown:
.rept (0x78 - 20)
pushl $0x0 # push error code place holder on the stack
# push $0xxx # push vector number
.byte 0x6a
.long ( . - INTUnknown - 3 ) / 9 + 20 # vector number
jmpCommonIdtEntry
.endr
commonIdtEntry:
pushal
movl %esp, %ebp
##
## At this point the stack looks like this:
##
## eflags
## Calling CS
## Calling EIP
## Error code or 0
## Int num or 0ffh for unknown int num
## eax
## ecx
## edx
## ebx
## esp
## ebp
## esi
## edi <------- ESP, EBP
##
call ClearScreen
movl String1, %esi
call PrintString
movl 32(%ebp), %eax ## move Int number into EAX
cmpl $19, %eax
ja PrintDefaultString
PrintExceptionString:
shll $2, %eax ## multiply by 4 to get offset from StringTable to actual string address
addl StringTable, %eax
movl (%eax), %esi
jmp PrintTheString
PrintDefaultString:
movl IntUnknownString, %esi
# patch Int number
movl %eax, %edx
call A2C
movb %al, 1(%esi)
movl %edx, %eax
shrl $4, %eax
call A2C
movb %al, (%esi)
PrintTheString:
call PrintString
movl String2, %esi
call PrintString
movl 44(%ebp), %eax # CS
call PrintDword
movb ':', %al
movb %al, (%edi)
addl $2, %edi
movl 40(%ebp), %eax # EIP
call PrintDword
movl String3, %esi
call PrintString
movl $0xb8140, %edi
movl StringEax, %esi # eax
call PrintString
movl 28(%ebp), %eax
call PrintDword
movl StringEbx, %esi # ebx
call PrintString
movl 16(%ebp), %eax
call PrintDword
movl StringEcx, %esi # ecx
call PrintString
movl 24(%ebp), %eax
call PrintDword
movl StringEdx, %esi # edx
call PrintString
movl 20(%ebp), %eax
call PrintDword
movl StringEcode, %esi # error code
call PrintString
movl 36(%ebp), %eax
call PrintDword
movl $0xb81e0, %edi
movl StringEsp, %esi # esp
call PrintString
movl 12(%ebp), %eax
call PrintDword
movl StringEbp, %esi # ebp
call PrintString
movl 8(%ebp), %eax
call PrintDword
movl StringEsi, %esi # esi
call PrintString
movl 4(%ebp), %eax
call PrintDword
movl StringEdi, %esi # edi
call PrintString
movl (%ebp), %eax
call PrintDword
movl StringEflags, %esi # eflags
call PrintString
movl 48(%ebp), %eax
call PrintDword
movl $0xb8320, %edi
movl %ebp, %esi
addl $52, %esi
movl $8, %ecx
OuterLoop:
pushl %ecx
movl $8, %ecx
movl %edi, %edx
InnerLoop:
movl (%esi), %eax
call PrintDword
addl $4, %esi
movb ' ', %al
movb %al, (%edi)
addl $2, %edi
loop InnerLoop
popl %ecx
addl $0xa0, %edx
movl %edx, %edi
loop OuterLoop
movl $0xb8960, %edi
movl 40(%ebp), %eax # EIP
subl $32*4, %eax
movl %eax, %esi # esi = eip - 32 DWORD linear (total 64 DWORD)
movl $8, %ecx
OuterLoop1:
pushl %ecx
movl $8, %ecx
movl %edi, %edx
InnerLoop1:
movl (%esi), %eax
call PrintDword
addl $4, %esi
movb ' ', %al
movb %al, (%edi)
addl $2, %edi
loop InnerLoop1
popl %ecx
addl $0xa0, %edx
movl %edx, %edi
loop OuterLoop1
# wbinvd ; this intruction does not support in early than 486 arch
LN_C1:
jmp LN_C1
#
# return
#
movl %ebp, %esp
popal
addl $8, %esp # error code and INT number
iretl
PrintString:
pushl %eax
LN_C2:
movb (%esi), %al
cmpb $0, %al
je LN_C3
movb %al, (%edi)
incl %esi
addl $2, %edi
jmp LN_C2
LN_C3:
popl %eax
ret
## EAX contains dword to print
## EDI contains memory location (screen location) to print it to
PrintDword:
pushl %ecx
pushl %ebx
pushl %eax
movl $8, %ecx
looptop:
roll $4, %eax
movb %al, %bl
andb $0xf, %bl
addb '0', %bl
cmpb '9', %bl
jle LN_C4
addb $7, %bl
LN_C4:
movb %bl, (%edi)
addl $2, %edi
loop looptop
#wbinvd
popl %eax
popl %ebx
popl %ecx
ret
ClearScreen:
pushl %eax
pushl %ecx
movb $0x00, %al
movb $0xc, %ah
movl $0xb8000, %edi
movl $80*24, %ecx
LN_C5:
movw %ax, (%edi)
addl $2, %edi
loop LN_C5
movl $0xb8000, %edi
popl %ecx
popl %eax
ret
A2C:
andb $0xf, %al
addb '0', %al
cmpb '9', %al
jle LN_C6
addb $7, %al
LN_C6:
ret
String1: .asciz "*** INT "
Int0String: .asciz "00h Divide by 0 -"
Int1String: .asciz "01h Debug exception -"
Int2String: .asciz "02h NMI -"
Int3String: .asciz "03h Breakpoint -"
Int4String: .asciz "04h Overflow -"
Int5String: .asciz "05h Bound -"
Int6String: .asciz "06h Invalid opcode -"
Int7String: .asciz "07h Device not available -"
Int8String: .asciz "08h Double fault -"
Int9String: .asciz "09h Coprocessor seg overrun (reserved) -"
Int10String: .asciz "0Ah Invalid TSS -"
Int11String: .asciz "0Bh Segment not present -"
Int12String: .asciz "0Ch Stack fault -"
Int13String: .asciz "0Dh General protection fault -"
Int14String: .asciz "0Eh Page fault -"
Int15String: .asciz "0Fh (Intel reserved) -"
Int16String: .asciz "10h Floating point error -"
Int17String: .asciz "11h Alignment check -"
Int18String: .asciz "12h Machine check -"
Int19String: .asciz "13h SIMD Floating-Point Exception -"
IntUnknownString: .asciz "??h Unknown interrupt -"
StringTable: .long Int0String, Int1String, Int2String, Int3String, \
Int4String, Int5String, Int6String, Int7String, \
Int8String, Int9String, Int10String, Int11String, \
Int12String, Int13String, Int14String, Int15String,\
Int16String, Int17String, Int18String, Int19String
String2: .asciz " HALT!! *** ("
String3: .asciz ")"
StringEax: .asciz "EAX="
StringEbx: .asciz "EBX="
StringEcx: .asciz "ECX="
StringEdx: .asciz "EDX="
StringEcode: .asciz "ECODE="
StringEsp: .asciz "ESP="
StringEbp: .asciz "EBP="
StringEsi: .asciz "ESI="
StringEdi: .asciz "EDI="
StringEflags: .asciz "EFLAGS="
Idtr: .float 0
.org 0x21ffe
BlockSignature:
.word 0xaa55
|