diff options
Diffstat (limited to 'contrib/baremetal/startmpcc.S')
| -rw-r--r-- | contrib/baremetal/startmpcc.S | 756 |
1 files changed, 756 insertions, 0 deletions
diff --git a/contrib/baremetal/startmpcc.S b/contrib/baremetal/startmpcc.S new file mode 100644 index 00000000..07486ce5 --- /dev/null +++ b/contrib/baremetal/startmpcc.S @@ -0,0 +1,756 @@ +/* #defines because ljmp wants a number, probably gas bug */ +/* .equ KERN_CODE_SEG,_pmcs-_gdt */ +#define KERN_CODE_SEG 0x08 + .equ KERN_DATA_SEG,_pmds-_gdt +/* .equ REAL_CODE_SEG,_rmcs-_gdt */ +#define REAL_CODE_SEG 0x18 + .equ REAL_DATA_SEG,_rmds-_gdt + .equ CR0_PE,1 + +#ifdef GAS291 +#define DATA32 data32; +#define ADDR32 addr32; +#define LJMPI(x) ljmp x +#else +#define DATA32 data32 +#define ADDR32 addr32 +/* newer GAS295 require #define LJMPI(x) ljmp *x */ +#define LJMPI(x) ljmp x +#endif + +#define PIC1_VBS 0x08 /* PIC1 interrupts start at vector 64 */ +#define PIC2_VBS 0x70 /* PIC1 interrupts start at vector 112 */ + +/* + * NOTE: if you write a subroutine that is called from C code (gcc/egcs), + * then you only have to take care of %ebx, %esi, %edi and %ebp. These + * registers must not be altered under any circumstance. All other registers + * may be clobbered without any negative side effects. If you don't follow + * this rule then you'll run into strange effects that only occur on some + * gcc versions (because the register allocator may use different registers). + * + * All the data32 prefixes for the ljmp instructions are necessary, because + * the assembler emits code with a relocation address of 0. This means that + * all destinations are initially negative, which the assembler doesn't grok, + * because for some reason negative numbers don't fit into 16 bits. The addr32 + * prefixes are there for the same reasons, because otherwise the memory + * references are only 16 bit wide. Theoretically they are all superfluous. + * One last note about prefixes: the data32 prefixes on all call _real_to_prot + * instructions could be removed if the _real_to_prot function is changed to + * deal correctly with 16 bit return addresses. I tried it, but failed. + */ + +/************************************************************************** +START - Where all the fun begins.... +**************************************************************************/ +/* this must be the first thing in the file because we enter from the top */ + .global _start + .code32 +_start: + cli + + /* load new IDT and GDT */ + lgdt gdtarg + lidt Idt_Reg + /* flush prefetch queue, and reload %cs:%eip */ + ljmp $KERN_CODE_SEG,$1f +1: + + /* reload other segment registers */ + movl $KERN_DATA_SEG,%eax + movl %eax,%ds + movl %eax,%es + movl %eax,%ss + movl $stktop,%esp + + /* program the PITs in order to stop them */ + mov $0x30,%al + out %al,$0x43 + out %al,$0x40 + mov $0x70,%al + out %al,$0x43 + out %al,$0x41 + mov $0xf0,%al + out %al,$0x43 + out %al,$0x42 + + call main + /* fall through */ + + .globl exit +exit: +2: + ljmp $KERN_CODE_SEG,$2b + +/************************************************************************** +MEMSIZE - Determine size of extended memory +**************************************************************************/ + .globl memsize +memsize: +#if 0 + pushl %ebx + pushl %esi + pushl %edi + call _prot_to_real + .code16 + movw $0xe801,%ax + stc + int $0x15 + jc 1f + andl $0xffff,%eax + andl $0xffff,%ebx + shll $6,%ebx + addl %ebx,%eax + jmp 2f +1: + movw $0x8800,%ax + int $0x15 + andl $0xffff,%eax +2: + movl %eax,%esi + DATA32 call _real_to_prot + .code32 + movl %esi,%eax + popl %edi + popl %esi + popl %ebx +#else + mov $32768,%eax +#endif + ret + +/************************************************************************** +XSTART - Transfer control to the kernel just loaded +**************************************************************************/ + .code16 + + .globl _int08_handler +_int08_handler: + movb $0x20, %al + outb %al, $0x20 + iret + + .globl _int10_handler +_int10_handler: + cmp $0x3, %ah + jnz _int10_04 + mov $0x0, %dx + mov $0x0, %cx + iret +_int10_04: + cmp $0x4, %ah + jnz _int10_05 + mov $0x0, %ah + iret +_int10_05: + cmp $0x5, %ah + jnz _int10_08 + mov $0x0, %al + iret +_int10_08: + cmp $0x8, %ah + jnz _int10_0D + mov $0x20, %al + mov $0x7, %ah + iret +_int10_0D: + cmp $0xD, %ah + jnz _int10_0F + mov $0x0, %al + iret +_int10_0F: + cmp $0xF, %ah + jnz _int10_XX + mov $0xb, %al + mov $80, %ah + mov $0, %bh +_int10_XX: + iret + + .globl _int11_handler +_int11_handler: + mov $0x22, %ax + iret + + .globl _int12_handler +_int12_handler: + mov $640, %ax + iret + + .globl _int13_handler +_int13_handler: + clc + mov $0, %ah + iret + + .globl _int14_handler +_int14_handler: + iret + + .globl _int15_handler +_int15_handler: + cmp $0xe801,%ax + jz _int15_008 + cmp $0x0, %ah + jz _int15_000 + cmp $0x1, %ah + jz _int15_000 + cmp $0x2, %ah + jz _int15_000 + cmp $0x3, %ah + jz _int15_000 + cmp $0xf, %ah + jz _int15_000 + cmp $0x21, %ah + jz _int15_000 + cmp $0x40, %ah + jz _int15_000 + cmp $0x41, %ah + jz _int15_000 + cmp $0x42, %ah + jz _int15_000 + cmp $0x43, %ah + jz _int15_000 + cmp $0x44, %ah + jz _int15_000 + cmp $0x80, %ah + jz _int15_001 + cmp $0x81, %ah + jz _int15_001 + cmp $0x82, %ah + jz _int15_002 + cmp $0x83, %ah + jz _int15_003 + cmp $0x84, %ah + jz _int15_000 + cmp $0x85, %ah + jz _int15_004 + cmp $0x86, %ah + jz _int15_003 + cmp $0x87, %ah + jz _int15_005 + cmp $0x88, %ah + jz _int15_006 + cmp $0x89, %ah + jz _int15_005 + cmp $0x90, %ah + jz _int15_007 + cmp $0xc0, %ah + jz _int15_000 + cmp $0xc1, %ah + jz _int15_000 + cmp $0xc2, %ah + jz _int15_000 + cmp $0xc3, %ah + jz _int15_000 + cmp $0xc4, %ah + jz _int15_000 + iret + +_int15_000: + mov $0x86, %ah + stc + iret + +_int15_001: + mov $0, %bx + mov $0, %cx + iret + +_int15_002: + mov $0, %bx + iret + +_int15_003: + clc + iret + +_int15_004: + mov $0, %al + iret + +_int15_005: + mov $0, %ah + clc + cmp $0, %ah + iret + +_int15_006: + mov $0xf000, %ax + iret + +_int15_007: + stc + iret + +_int15_008: + clc + mov $1024, %dx /* dx -> extended memory size (in 64K chuncks) */ + mov $640, %cx /* cx -> conventional memory size (in 1 Kbytes chuncks) */ + iret + + .globl _int16_handler +_int16_handler: + cmp $0x0, %ah + jnz _int16_01 + mov $0x20, %al + mov $0x39, %ah + iret +_int16_01: + cmp $0x1, %ah + jnz _int16_02 + iret +_int16_02: + cmp $0x2, %ah + jnz _int16_05 + mov $0, %al + iret +_int16_05: + cmp $0x5, %ah + jnz _int16_10 + mov $0, %al + iret +_int16_10: + cmp $0x10, %ah + jnz _int16_11 + mov $0x20, %al + mov $0x39, %ah + iret +_int16_11: + cmp $0x11, %ah + jnz _int16_12 + iret +_int16_12: + cmp $0x12, %ah + jnz _int16_XX + mov $0, %ax + iret +_int16_XX: + iret + + .globl _int17_handler +_int17_handler: + mov $0xd0, %ah + iret + + .globl _int19_handler +_int19_handler: + hlt + iret + + .globl _int1A_handler +_int1A_handler: + stc + iret + + .code32 + .globl xstart +xstart: + /* reprogram the PICs so that interrupt are masked */ + movb $0x11,%al /* ICW1 [ICW4 NEEDED, EDGE TRIGGERED]*/ + outb %al,$0x20 + movb $PIC1_VBS, %al + outb %al,$0x21 + movb $0x4,%al + outb %al,$0x21 + movb $0x1,%al + outb %al,$0x21 + movb $0xff,%al + outb %al,$0x21 + + movb $0x11,%al /* ICW1 [ICW4 NEEDED, EDGE TRIGGERED]*/ + outb %al,$0xa0 + movb $PIC2_VBS, %al + outb %al,$0xa1 + movb $0x2,%al + outb %al,$0xa1 + movb $0x1,%al + outb %al,$0xa1 + movb $0xff,%al + outb %al,$0xa1 + + pushl %ebp + movl %esp,%ebp + pushl %ebx + pushl %esi + pushl %edi + movl 8(%ebp),%eax + movl %eax,_execaddr + movl 12(%ebp),%ebx + movl 16(%ebp),%ecx /* bootp record (32bit pointer) */ + addl $28,%ecx /* ip, udp header */ + shll $12,%ecx + shrw $12,%cx + call _prot_to_real + .code16 +/* MP: add int10 handler */ + push %eax + push %ebx + push %es + mov $0,%ax + mov %ax,%es + mov %cs,%ax + shl $16,%eax + + ADDR32 mov $(_int08_handler-_start),%ax + mov $0x20,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int10_handler-_start),%ax + mov $0x40,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int11_handler-_start),%ax + mov $0x44,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int12_handler-_start),%ax + mov $0x48,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int13_handler-_start),%ax + mov $0x4c,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int14_handler-_start),%ax + mov $0x50,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int15_handler-_start),%ax + mov $0x54,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int16_handler-_start),%ax + mov $0x58,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int17_handler-_start),%ax + mov $0x5c,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int19_handler-_start),%ax + mov $0x64,%ebx + mov %eax,%es:(%bx) + + ADDR32 mov $(_int1A_handler-_start),%ax + mov $0x68,%ebx + mov %eax,%es:(%bx) + + pop %es + pop %ebx + pop %eax +/* */ + pushl %ecx /* bootp record */ + pushl %ebx /* file header */ + movl $((RELOC<<12)+(1f-RELOC)),%eax + pushl %eax + ADDR32 LJMPI(_execaddr-_start) +1: + addw $8,%sp /* XXX or is this 10 in case of a 16bit "ret" */ + DATA32 call _real_to_prot + .code32 + popl %edi + popl %esi + popl %ebx + popl %ebp + ret + +_execaddr: + .long 0 + +#ifdef IMAGE_MULTIBOOT +/************************************************************************** +XEND - Restart Etherboot from the beginning (from protected mode) +**************************************************************************/ + + .globl xend +xend: + cs + lidt idtarg_realmode-_start+RELOC + cs + lgdt gdtarg-_start+RELOC +#ifdef GAS291 + ljmp $REAL_CODE_SEG,$1f-RELOC /* jump to a 16 bit segment */ +#else + ljmp $REAL_CODE_SEG,$1f-_start /* jump to a 16 bit segment */ +#endif /* GAS291 */ +1: + .code16 + movw $REAL_DATA_SEG,%ax + movw %ax,%ds + movw %ax,%ss + movw %ax,%es + + /* clear the PE bit of CR0 */ + movl %cr0,%eax + andl $0!CR0_PE,%eax + movl %eax,%cr0 + + /* make intersegment jmp to flush the processor pipeline + * and reload %cs:%eip (to clear upper 16 bits of %eip). + */ + DATA32 ljmp $(RELOC)>>4,$2f-_start +2: + /* we are in real mode now + * set up the real mode segment registers : %ds, %ss, %es + */ + movw %cs,%ax + movw %ax,%ds + movw %ax,%es + movw %ax,%ss + xorl %esp,%esp + ADDR32 movw initsp-RELOC,%sp + + movw $0,%ax + movw %ax,%fs + movw %ax,%gs + + sti + jmp _start + + .code32 +#endif /* IMAGE_MULTIBOOT */ + +.global get_cs +get_cs: + xorl %eax,%eax + movw %cs,%ax + ret + +.global get_ds +get_ds: + xorl %eax,%eax + movw %ds,%ax + ret + +.global getsp +getsp: + movl %esp,%eax /* GET STACK POINTER */ + subl $4, %eax /* ACCOUNT FOR RETURN ADDRESS ON */ + ret + +.global get_gdtbase +get_gdtbase: + sub $8,%esp /* ALLOCATE ROOM ON THE STACK */ + sgdt (%esp,1) /*STORE IGDT REGISTER ON STACK */ + mov 2(%esp),%eax /* READ GDT BASE ADDRESS */ + mov $KERN_DATA_SEG,%dx /* ASSUME UNIVERSAL DS. */ + add $8,%esp /* RESTORE STACK */ + ret /* DONE */ + +.global get_gdtsize +get_gdtsize: + sub $8,%esp /* ALLOCATE ROOM ON THE STACK */ + sgdt (%esp,1) /*STORE IGDT REGISTER ON STACK */ + xor %eax,%eax + mov 2(%esp),%eax /* READ GDT BASE ADDRESS */ + mov (%ESP),%ax + shr $3,%ax + add $8,%esp /* RESTORE STACK */ + ret /* DONE */ + +.global get_idtbase +get_idtbase: + sub $8,%esp + sidt (%esp,1) /* STORE IIDT REGISTER ON STACK */ + mov 2(%esp),%eax + mov $KERN_DATA_SEG,%dx + add $8,%esp + ret + +.global get_lw +get_lw: + xor %edx,%edx + mov 8(%esp),%eax + mov 4(%esp),%dx + ret + +/************************************************************************** +SETJMP - Save stack context for non-local goto +**************************************************************************/ + .globl setjmp +setjmp: + mov 4(%esp),%ecx + mov 0(%esp),%edx + mov %edx,0(%ecx) + mov %ebx,4(%ecx) + mov %esp,8(%ecx) + mov %ebp,12(%ecx) + mov %esi,16(%ecx) + mov %edi,20(%ecx) + mov %eax,24(%ecx) + mov $0,%eax + ret + +/************************************************************************** +LONGJMP - Non-local jump to a saved stack context +**************************************************************************/ + .globl longjmp +longjmp: + mov 4(%esp),%edx + mov 8(%esp),%eax + mov 0(%edx),%ecx + mov 4(%edx),%ebx + mov 8(%edx),%esp + mov 12(%edx),%ebp + mov 16(%edx),%esi + mov 20(%edx),%edi + cmp $0,%eax + jne 1f + mov $1,%eax +1: mov %ecx,0(%esp) + ret + +/************************************************************************** +_REAL_TO_PROT - Go from REAL mode to Protected Mode +**************************************************************************/ + .globl _real_to_prot +_real_to_prot: + .code16 + cli + cs + ADDR32 lgdt gdtarg-_start + movl %cr0,%eax + orl $CR0_PE,%eax + movl %eax,%cr0 /* turn on protected mode */ + + /* flush prefetch queue, and reload %cs:%eip */ + DATA32 ljmp $KERN_CODE_SEG,$1f +1: + .code32 + /* reload other segment registers */ + movl $KERN_DATA_SEG,%eax + movl %eax,%ds + movl %eax,%es + movl %eax,%ss + addl $RELOC,%esp /* Fix up stack pointer */ + xorl %eax,%eax + movl %eax,%fs + movl %eax,%gs + popl %eax /* Fix up return address */ + addl $RELOC,%eax + pushl %eax + ret + +/************************************************************************** +_PROT_TO_REAL - Go from Protected Mode to REAL Mode +**************************************************************************/ + .globl _prot_to_real +_prot_to_real: + .code32 + popl %eax + subl $RELOC,%eax /* Adjust return address */ + pushl %eax + subl $RELOC,%esp /* Adjust stack pointer */ +#ifdef GAS291 + ljmp $REAL_CODE_SEG,$1f-RELOC /* jump to a 16 bit segment */ +#else + ljmp $REAL_CODE_SEG,$1f-_start /* jump to a 16 bit segment */ +#endif /* GAS291 */ +1: + .code16 + movw $REAL_DATA_SEG,%ax + movw %ax,%ds + movw %ax,%ss + movw %ax,%es + movw %ax,%fs + movw %ax,%gs + cli + + /* clear the PE bit of CR0 */ + movl %cr0,%eax + andl $0!CR0_PE,%eax + movl %eax,%cr0 + + /* make intersegment jmp to flush the processor pipeline + * and reload %cs:%eip (to clear upper 16 bits of %eip). + */ + DATA32 ljmp $(RELOC)>>4,$2f-_start +2: + /* we are in real mode now + * set up the real mode segment registers : %ds, $ss, %es + */ + movw %cs,%ax + movw %ax,%ds + movw %ax,%es + movw %ax,%ss +#if 0 + sti +#endif + DATA32 ret /* There is a 32 bit return address on the stack */ + .code32 + +/************************************************************************** +GLOBAL DESCRIPTOR TABLE +**************************************************************************/ + .align 4 +Idt_Reg: + .word 0x3ff + .long 0 + + .align 4 +_gdt: +gdtarg: +Gdt_Table: + .word 0x27 /* limit */ + .long _gdt /* addr */ + .word 0 +_pmcs: + /* 32 bit protected mode code segment */ + .word 0xffff,0 + .byte 0,0x9f,0xcf,0 + +_pmds: + /* 32 bit protected mode data segment */ + .word 0xffff,0 + .byte 0,0x93,0xcf,0 + +_rmcs: + /* 16 bit real mode code segment */ + .word 0xffff,(RELOC&0xffff) + .byte (RELOC>>16),0x9b,0x00,(RELOC>>24) + +_rmds: + /* 16 bit real mode data segment */ + .word 0xffff,(RELOC&0xffff) + .byte (RELOC>>16),0x93,0x00,(RELOC>>24) + + .align 4 +RUN_GDT: /* POINTER TO GDT IN RAM */ + .byte 0x7f,0 /* [BSP_GDT_NUM*8]-1 */ + .long Gdt_Table + + .align 4 + + .section ".rodata" +err_not386: + .ascii "Etherboot/32 requires 386+" + .byte 0x0d, 0x0a +err_not386_end: + +days: .long 0 +irq_num: .long + + .data + .align 4 + .org 2048 +.global stktop +stktop: + .long + +.section ".armando" +/* 1:::::::::2:::::::::3:::::::3 */ +/* 12345678901234567890123456789012345678 */ +/* v----+----v----+----v----+----v----+--- */ + +.global EtherbootString +EtherbootString: +.ascii "EtherBoot MPCC " /* fw identifier */ + +.byte 0, 0 /* mandatory hole */ + +.long _start /* entry point */ +.word 0 +.byte 'E' /* type */ +.byte 0 /* selector */ +.word 0 /* CRC */ |