Chameleon

Chameleon Commit Details

Date:2015-03-09 21:26:30 (9 years 1 month ago)
Author:zenith432
Commit:2597
Parents: 2596
Message:Sanitize 16-bit assembly
Changes:
M/branches/zenith432/i386/boot2/boot.c
M/branches/zenith432/i386/libsa/interrupts.c
M/branches/zenith432/i386/libsaio/table.c
M/branches/zenith432/i386/boot2/boot2.s
M/branches/zenith432/i386/libsaio/bios.s
M/branches/zenith432/i386/libsaio/saio_internal.h
M/branches/zenith432/i386/libsaio/asm.s
M/branches/zenith432/i386/boot2/mboot.c

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branches/zenith432/i386/libsaio/asm.s
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#include <architecture/i386/asm_help.h>␊
#include "memory.h"␊
␊
#define data32 .byte 0x66␊
#define addr32 .byte 0x67␊
␊
.file "asm.s"␊
␊
CR0_PE_ON = 0x1␊
.globl _Gdtr␊
//.data␊
.section __INIT,__data␉// turbo - Data that must be in the first segment␊
.align 2, 0x90␊
.align 2␊
_Gdtr:␊
.word GDTLIMIT␊
.long vtop(_Gdt)␊
.section __INIT,__data␉// turbo - Data that must be in the first segment␊
// Real mode IDT␊
.align 2␊
.globl _Idtr_real␊
_Idtr_real:␊
.word 0x03ff␊
.long 0x00000000␊
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -␊
// Data area for __switch_stack.␊
//␊
.align 2␊
save_sp: .long STACK_OFS␊
save_ss: .long STACK_SEG␊
save_ss: .word STACK_SEG␊
␊
//.text␊
.section __INIT,__text // turbo - This code must reside within the first segment␊
.section __INIT,__text,regular,pure_instructions // turbo - This code must reside within the first segment␊
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -␊
// real_to_prot()␊
//␊
//␊
LABEL(__real_to_prot)␊
␊
.code16␊
␊
// Interrupts are disabled in protected mode.␊
␊
cli␊
␊
// Load the Global Descriptor Table Register (GDTR).␊
␊
addr32␊
data32␊
lgdt OFFSET16(_Gdtr)␊
lgdtl OFFSET16(_Gdtr)␊
␊
// Enter protected mode by setting the PE bit in CR0.␊
␊
mov %cr0, %eax␊
data32␊
or $CR0_PE_ON, %eax␊
or $CR0_PE_ON, %ax␊
mov %eax, %cr0␊
␊
// Make intrasegment jump to flush the processor pipeline and␊
// reload CS register.␊
␊
data32␊
ljmp $0x08, $xprot␊
ljmpl $0x08, $xprot␊
␊
.code32␊
␊
xprot:␊
// we are in USE32 mode now␊
// set up the protected mode segment registers : DS, SS, ES, FS, GS␊
␊
mov $0x10, %eax␊
movw $0x10, %ax␊
movw %ax, %ds␊
movw %ax, %ss␊
movw %ax, %es␊
␊
popl %eax␊
addl $CODE32_BASE, %eax␊
pushl %eax␊
jmp *%eax␊
␊
ret␊
␊
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -␊
// prot_to_real()␊
//␊
ljmp $0x18, $x16 // change to USE16 mode␊
␊
x16:␊
␊
.code16␊
␊
mov %cr0, %eax // clear the PE bit of CR0␊
data32␊
and $CR0_PE_OFF, %eax␊
mov %eax, %cr0␊
␊
// make intersegment jmp to flush the processor pipeline␊
// and reload CS register␊
␊
data32␊
ljmp $CODE16_SEG, $xreal - CODE32_BASE␊
ljmp $CODE16_SEG, $xreal␊
␊
xreal:␊
// we are in real mode now␊
␊
// load stack segment register SS.␊
␊
data32␊
movl $STACK16_SEG, %eax␊
movw $STACK16_SEG, %ax␊
movw %ax, %ss␊
␊
// clear top 16-bits of ESP and EBP.␊
␊
data32␊
movzwl %sp, %esp␊
data32␊
movzwl %bp, %ebp␊
␊
// Modify caller's return address on the stack␊
// from linear address to segment offset.␊
␊
data32␊
popl %eax␊
data32␊
movzwl %ax, %eax␊
data32␊
pushl %eax␊
␊
// Reenable maskable interrupts.␊
␊
sti␊
␊
data32␊
ret␊
jmp *%ax␊
␊
.code32␊
␊
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -␊
// halt()␊
//␊
// Passes arg to the program in %eax.␊
//␊
LABEL(_startprog)␊
push %ebp␊
mov %esp, %ebp␊
cli␊
xor %eax, %eax␊
mov %eax, _Idtr_prot␊
movw %ax, _Idtr_prot + 4␊
lidt _Idtr_prot␊
␊
mov 0xc(%ebp), %eax // argument to program - bootargs to mach_kernel␊
mov 0x8(%ebp), %ecx // entry offset ␊
mov $0x28, %ebx // segment␊
push %ebx␊
push %ecx␊
add $4, %esp // discard return address␊
mov $0x28, %eax // segment␊
xchg 4(%esp), %eax // argument to program - bootargs to mach_kernel␊
␊
// set up %ds and %es␊
␊
mov $0x20, %ebx␊
movw $0x20, %bx␊
movw %bx, %ds␊
movw %bx, %es␊
␊
// AX, DI, and SI are clobbered.␊
//␊
LABEL(__switch_stack)␊
popl %eax # save return address␊
popl %edi # discard upper 16-bit␊
␊
data32␊
addr32␊
movl OFFSET16(save_ss), %esi # new SS to SI␊
.code16␊
␊
data32␊
addr32␊
pop %ax # save return address␊
pop %di # discard upper 16-bit␊
␊
movw OFFSET16(save_ss), %si # new SS to SI␊
␊
movl OFFSET16(save_sp), %edi # new SP to DI␊
␊
addr32␊
mov %ss, OFFSET16(save_ss) # save current SS to memory␊
movw %ss, OFFSET16(save_ss) # save current SS to memory␊
␊
data32␊
addr32␊
movl %esp, OFFSET16(save_sp) # save current SP to memory␊
␊
cli␊
mov %si, %ss # switch stack␊
mov %di, %sp␊
mov %edi, %esp␊
sti␊
␊
pushl %eax # push IP of caller onto the new stack␊
push %ax # push IP of caller onto the new stack␊
␊
xorl %eax, %eax␊
xorl %esi, %esi␊
xorl %edi, %edi␊
xor %ax, %ax␊
xor %si, %si␊
xor %di, %di␊
␊
ret␊
␊
.code32␊
␊
#ifndef BOOT1␊
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -␊
// loader()␊
//␊
LABEL(_loader)␊
enter $0, $0␊
pushfl␊
cli␊
pushal␊
␊
#␊
␊
###### Real Mode Begin ######␊
␊
data32␊
call __switch_stack # Switch to NBP stack␊
.code16␊
␊
calll __switch_stack # Switch to NBP stack␊
␊
int $0x2b # Call NBP␊
␊
data32␊
call __switch_stack # Restore stack␊
calll __switch_stack # Restore stack␊
␊
data32␊
call __real_to_prot # Back to protected mode␊
calll __real_to_prot # Back to protected mode␊
␊
.code32␊
␊
###### Real Mode End ######␊
␊
popal␊
popfl␊
leave␊
ret␊
#endif␊
branches/zenith432/i386/libsaio/bios.s
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#include <architecture/i386/asm_help.h>␊
#include "memory.h"␊
␊
#define data32 .byte 0x66␊
#define addr32 .byte 0x67␊
␊
#define O_INT 0␊
#define O_EAX 4␊
#define O_EBX 8␊
bits of code and data within the first 63.5k and modify the loaders to␊
be able to load more than 63.5k.␊
*/␊
.align 4␊
.align 2␊
save_eax: .space 4␊
.align 4␊
save_edx: .space 4␊
.align 2␊
save_es: .space 2␊
.align 2␊
save_flag: .space 2␊
.align 4␊
new_eax: .space 4␊
.align 4␊
new_edx: .space 4␊
.align 2␊
new_es: .space 2␊
.align 2␊
new_ds: .space 2␊
␊
.section __INIT,__text // turbo - This code must reside within the first segment␊
.section __INIT,__text,regular,pure_instructions // turbo - This code must reside within the first segment␊
␊
␊
/*============================================================================␊
␊
call __prot_to_real␊
␊
data32␊
addr32␊
mov OFFSET16(new_eax), %eax␊
data32␊
addr32␊
.code16␊
␊
mov new_eax, %eax // OFFSET16 not needed due to special opcode for ax/eax␊
mov OFFSET16(new_edx), %edx␊
data32␊
addr32␊
mov OFFSET16(new_es), %es␊
movw OFFSET16(new_es), %es␊
␊
push %ds // Save DS␊
// Replace DS. WARNING: Don't access data until it's restored!␊
addr32␊
data32␊
mov OFFSET16(new_ds), %ds␊
movw OFFSET16(new_ds), %ds␊
␊
do_int:␊
int $0x00␊
pop %ds // Restore DS before we do anything else␊
␊
pushf␊
data32␊
addr32␊
movl %eax, OFFSET16(save_eax)␊
popl %eax // actually pop %ax␊
addr32␊
movl %eax, OFFSET16(save_flag) // actually movw␊
mov %eax, save_eax␊
pop %ax␊
mov %ax, save_flag␊
mov %es, %ax␊
addr32␊
movl %eax, OFFSET16(save_es) // actually movw␊
data32␊
call __real_to_prot␊
mov %ax, save_es␊
calll __real_to_prot␊
␊
.code32␊
␊
movl %edx, new_edx // save new edx before clobbering␊
movl save_edx, %edx␊
movl new_edx, %eax // now move it into buffer␊
branches/zenith432/i386/libsaio/table.c
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};␊
␊
// turbo - GDT must be in first 64k segment␊
struct seg_desc __attribute__ ((section("__INIT,__data"))) Gdt[ NGDTENT ] = {␊
struct seg_desc __attribute__ ((section("__INIT,__data"), aligned(8))) Gdt[ NGDTENT ] = {␊
/* 0x0 : null */␊
{0x0000, 0x0000, 0x00, 0x00, 0x00, 0x00},␊
␊
branches/zenith432/i386/libsaio/saio_internal.h
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/* asm.s */␊
extern void␉␉real_to_prot(void);␊
extern void␉␉prot_to_real(void);␊
extern void␉␉halt(void);␊
extern void␉␉startprog(unsigned int address, void *arg);␊
extern void␉␉halt(void) __attribute__((noreturn));␊
extern void␉␉startprog(unsigned int address, void *arg) __attribute__((noreturn));␊
extern void␉␉loader(UInt32 code, UInt32 cmdptr);␊
extern uint64_t␉␉computeRand(void);␊
␊
branches/zenith432/i386/boot2/mboot.c
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#define FIX_RETURN_ADDRESS_USING_FIRST_ARG(arg) \␊
RETURN_ADDRESS_USING_FIRST_ARG(arg) -= OFFSET_1MEG␊
␊
extern void jump_to_chainbooter();␊
extern void jump_to_chainbooter() __attribute__((noreturn));␊
extern unsigned char chainbootdev;␊
extern unsigned char chainbootflag;␊
␊
branches/zenith432/i386/boot2/boot.c
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␉␉// Notify modules that the kernel is about to be started␊
␉␉execute_hook("Kernel Start", (void *)kernelEntry, (void *)bootArgs, NULL, NULL);␊
␊
␉␉if (interruptsAvailable)␊
␉␉{␊
␉␉␉DisableInterrupts();␊
␉␉}␊
␊
␉␉// Masking out so that Lion doesn't doublefault␊
␉␉outb(0x21, 0xff);␉/* Maskout all interrupts Pic1 */␊
␉␉outb(0xa1, 0xff);␉/* Maskout all interrupts Pic2 */␊
␉␉// Notify modules that the kernel is about to be started␊
␉␉execute_hook("Kernel Start", (void*)kernelEntry, (void*)bootArgsPreLion, NULL, NULL);␊
␊
␉␉if (interruptsAvailable)␊
␉␉{␊
␉␉␉DisableInterrupts();␊
␉␉}␊
␊
␊
␉␉startprog( kernelEntry, bootArgsPreLion );␊
␉}␊
␊
branches/zenith432/i386/boot2/boot2.s
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#include "memory.h"␊
#include "mboot.h"␊
␊
#define data32 .byte 0x66␊
#define retf .byte 0xcb␊
␊
.file "boot2.s"␊
.section __INIT,__text␉// turbo - This initialization code must reside within the first segment␊
.section __INIT,__text,regular,pure_instructions␉// turbo - This initialization code must reside within the first segment␊
␊
//.data␊
.section __INIT,__data␉// turbo - Data that must be in the first segment␊
# Returns:␊
#␊
LABEL(boot2) # Entry point at 0:BOOTER_ADDR (will be called by boot1)␊
pushl %ecx # Save general purpose registers␊
pushl %ebx␊
pushl %ebp␊
pushl %esi␊
pushl %edi␊
␊
.code16␊
␊
push %cx # Save general purpose registers␊
push %bx␊
push %bp␊
push %si␊
push %di␊
push %ds # Save DS, ES␊
push %es␊
␊
mov %ax, %ds # Set DS and ES to match CS␊
mov %ax, %es␊
␊
data32␊
call __switch_stack # Switch to new stack␊
calll __switch_stack # Switch to new stack␊
␊
data32␊
call __real_to_prot # Enter protected mode.␊
calll __real_to_prot # Enter protected mode.␊
␊
.code32␊
␊
fninit # FPU init␊
␊
# We are now in 32-bit protected mode.␊
␊
call __prot_to_real # Back to real mode.␊
␊
data32␊
call __switch_stack # Restore original stack␊
␊
.code16␊
␊
calll __switch_stack # Restore original stack␊
␊
pop %es # Restore original ES and DS␊
pop %ds␊
popl %edi # Restore all general purpose registers␊
popl %esi # except EAX.␊
popl %ebp␊
popl %ebx␊
popl %ecx␊
pop %di # Restore all general purpose registers␊
pop %si # except AX.␊
pop %bp␊
pop %bx␊
pop %cx␊
␊
retf # Hardcode a far return␊
lret # Far return␊
␊
.code32␊
␊
start_chain_boot:␊
xorl %edx, %edx␊
movb _chainbootdev, %dl # Setup DL with the BIOS device number␊
␊
call __prot_to_real # Back to real mode.␊
␊
data32␊
call __switch_stack # Restore original stack␊
␊
.code16␊
␊
calll __switch_stack # Restore original stack␊
␊
pop %es # Restore original ES and DS␊
pop %ds␊
popl %edi # Restore all general purpose registers␊
popl %esi # except EAX.␊
popl %ebp␊
popl %ebx␊
popl %ecx␊
pop %di # Restore all general purpose registers␊
pop %si # except AX.␊
pop %bp␊
pop %bx␊
pop %cx␊
␊
data32␊
ljmp $0, $0x7c00 # Jump to boot code already in memory␊
␊
.code32␊
␊
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -␊
# Multiboot support added by David F. Elliott <dfe@cox.net> on 2007/06/26␊
# cannot do that and have GRUB find it because GRUB only searches the first␊
# 8k of the binary. Since __TEXT,__const follows __TEXT,__text (the code␊
# section) and since the code is well over 8k long, it doesn't work.␊
.align 4, 0x90 # Make sure we're on a 4-byte boundary. Required by Multiboot.␊
␊
//.data - the entire __INIT segment is less than 1k␊
.section __INIT,__data␉// turbo␊
␊
.align 2 # Make sure we're on a 4-byte boundary. Required by Multiboot.␊
_multiboot_header:␊
# magic (NOTE: this shows up as 02b0 ad1b in a hex dump)␊
.long MULTIBOOT_HEADER_MAGIC␊
# entry_addr␊
.long (_multiboot_entry + OFFSET_1MEG)␊
␊
# Stick a couple of nop here so that we hopefully make disassemblers realize we have instructions again␊
nop␊
nop␊
nop␊
.align 8, 0x90 # Align to 8 byte boundary which should be enough nops␊
//.text␊
.section __INIT,__text␉// turbo␊
␊
.align 3, 0x90 # Align to 8 byte boundary␊
␊
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -␊
_multiboot_entry:␊
# First thing's first, let's get ourselves a usable GDT.␊
# The desired offset in this case is exactly 1 MB higher than the␊
# assembler/linker thinks it is. As mentioned above, we use the kernel␊
# init code selector instead of the boot code selector.␊
jmp $0x28,$(Lpost_gdt_switch+OFFSET_1MEG)␊
ljmp $0x28,$(Lpost_gdt_switch+OFFSET_1MEG)␊
Lpost_gdt_switch:␊
␊
# Now that we have the right code selector we also want the rest of the␊
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -␊
# _continue_at_low_address does some trickery to get the caller running from the low address with the right selector␊
.globl _continue_at_low_address␊
.align 4, 0x90␊
.align 2, 0x90␊
_continue_at_low_address:␊
# Our stack frame has been set up with the return address on top␊
# First, fix that to be 1 MB lower␊
lgdt _Gdtr␊
# Now jump to GDT selector 8 using the low address of this function␊
# This finally puts us in low memory in the right selector (0x08)␊
jmpl $0x08,$L_continue_at_low_address_next␊
ljmp $0x08,$L_continue_at_low_address_next␊
L_continue_at_low_address_next:␊
# We don't need to set ss,ds,es,fs, or gs because they are already 0x10␊
# and the old GDT had the same information for selector 0x10 as the new␊
␊
call __prot_to_real # Back to real mode.␊
␊
.code16␊
␊
# TODO: Set SS:SP to something reasonable? For instance, Microsoft MBR␊
# code starts out by setting up the stack at 0:7c00 for itself and leaves␊
# that intact. Thus the stack by default will grow down from the code␊
# 0:fff0 and it seems that most boot code doesn't care and simply sets␊
# SS:SP itself as one of the first things it does.␊
␊
data32␊
ljmp $0, $0x7c00 # Jump to boot code already in memory␊
␊
.code32␊
␊
# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -␊
# _cause_crash jumps to offset 0 of a selector we know is not in our GDT␊
# This causes Parallels to output all sorts of nice debugging information␊
# We aren't using it right now so it's in an if 0 block.␊
#if 0␊
.globl _cause_crash␊
.align 4, 0x90␊
.align 2, 0x90␊
_cause_crash:␊
# Cause a crash, there is no GDT selector f0␊
jmp $0xf0,$0␊
ljmp $0xf0,$0␊
hlt␊
jmp _cause_crash␊
#endif␊
# See the comments above as to why we have OFFSET_1MEG.␊
//.data␊
.section __INIT,__data␉// turbo␊
.align 4, 0x90␊
.align 2␊
_Gdtr_high:␊
.word GDTLIMIT␊
.long vtop(_Gdt + OFFSET_1MEG)␊
␊
branches/zenith432/i386/libsa/interrupts.c
107107
108108
109109
110
110111
111112
112113
......
131132
132133
133134
135
134136
135137
136138
␉␉␉␉␉ "addl $4, %%esp\n\t"␊
␉␉␉␉␉ "iretl"␊
␉␉␉␉␉ :);␊
␉__builtin_unreachable();␊
}␊
␊
static␊
␉␉␉␉␉ "addl $8, %%esp\n\t"␊
␉␉␉␉␉ "iretl"␊
␉␉␉␉␉ :);␊
␉__builtin_unreachable();␊
}␊
␊
/*␊

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Revision: 2597