diff options
Diffstat (limited to 'src/arch/x86/lib/c_start.S')
| -rw-r--r-- | src/arch/x86/lib/c_start.S | 317 |
1 files changed, 317 insertions, 0 deletions
diff --git a/src/arch/x86/lib/c_start.S b/src/arch/x86/lib/c_start.S new file mode 100644 index 0000000000..94ce4a70c3 --- /dev/null +++ b/src/arch/x86/lib/c_start.S @@ -0,0 +1,317 @@ +#include <cpu/x86/post_code.h> + + .section ".text" + .code32 + .globl _start +_start: + cli + lgdt %cs:gdtaddr + ljmp $0x10, $1f +1: movl $0x18, %eax + movl %eax, %ds + movl %eax, %es + movl %eax, %ss + movl %eax, %fs + movl %eax, %gs + + post_code(0x13) /* post 13 */ + + /** clear stack */ + cld + leal _stack, %edi + movl $_estack, %ecx + subl %edi, %ecx + shrl $2, %ecx /* it is 32 bit aligned, right? */ + xorl %eax, %eax + rep + stosl + + /** clear bss */ + leal _bss, %edi + movl $_ebss, %ecx + subl %edi, %ecx + jz .Lnobss + shrl $2, %ecx /* it is 32 bit aligned, right? */ + xorl %eax, %eax + rep + stosl +.Lnobss: + + /* set new stack */ + movl $_estack, %esp + + /* Push the cpu index and struct cpu */ + pushl $0 + pushl $0 + + /* push the boot_complete flag */ + pushl %ebp + + /* Save the stack location */ + movl %esp, %ebp + + /* Initialize the Interrupt Descriptor table */ + leal _idt, %edi + leal vec0, %ebx + movl $(0x10 << 16), %eax /* cs selector */ + +1: movw %bx, %ax + movl %ebx, %edx + movw $0x8E00, %dx /* Interrupt gate - dpl=0, present */ + movl %eax, 0(%edi) + movl %edx, 4(%edi) + addl $6, %ebx + addl $8, %edi + cmpl $_idt_end, %edi + jne 1b + + /* Load the Interrupt descriptor table */ + lidt idtarg + + /* + * Now we are finished. Memory is up, data is copied and + * bss is cleared. Now we call the main routine and + * let it do the rest. + */ + post_code(0xfe) /* post fe */ + + /* Restore the stack location */ + movl %ebp, %esp + + /* The boot_complete flag has already been pushed */ + call hardwaremain + /* NOTREACHED */ +.Lhlt: + post_code(0xee) /* post ee */ + hlt + jmp .Lhlt + +vec0: + pushl $0 /* error code */ + pushl $0 /* vector */ + jmp int_hand +vec1: + pushl $0 /* error code */ + pushl $1 /* vector */ + jmp int_hand + +vec2: + pushl $0 /* error code */ + pushl $2 /* vector */ + jmp int_hand + +vec3: + pushl $0 /* error code */ + pushl $3 /* vector */ + jmp int_hand + +vec4: + pushl $0 /* error code */ + pushl $4 /* vector */ + jmp int_hand + +vec5: + pushl $0 /* error code */ + pushl $5 /* vector */ + jmp int_hand + +vec6: + pushl $0 /* error code */ + pushl $6 /* vector */ + jmp int_hand + +vec7: + pushl $0 /* error code */ + pushl $7 /* vector */ + jmp int_hand + +vec8: + /* error code */ + pushl $8 /* vector */ + jmp int_hand + .word 0x9090 + +vec9: + pushl $0 /* error code */ + pushl $9 /* vector */ + jmp int_hand + +vec10: + /* error code */ + pushl $10 /* vector */ + jmp int_hand + .word 0x9090 + +vec11: + /* error code */ + pushl $11 /* vector */ + jmp int_hand + .word 0x9090 + +vec12: + /* error code */ + pushl $12 /* vector */ + jmp int_hand + .word 0x9090 + +vec13: + /* error code */ + pushl $13 /* vector */ + jmp int_hand + .word 0x9090 + +vec14: + /* error code */ + pushl $14 /* vector */ + jmp int_hand + .word 0x9090 + +vec15: + pushl $0 /* error code */ + pushl $15 /* vector */ + jmp int_hand + +vec16: + pushl $0 /* error code */ + pushl $16 /* vector */ + jmp int_hand + +vec17: + /* error code */ + pushl $17 /* vector */ + jmp int_hand + .word 0x9090 + +vec18: + pushl $0 /* error code */ + pushl $18 /* vector */ + jmp int_hand + +vec19: + pushl $0 /* error code */ + pushl $19 /* vector */ + jmp int_hand + +int_hand: + /* At this point on the stack there is: + * 0(%esp) vector + * 4(%esp) error code + * 8(%esp) eip + * 12(%esp) cs + * 16(%esp) eflags + */ + pushl %edi + pushl %esi + pushl %ebp + /* Original stack pointer */ + leal 32(%esp), %ebp + pushl %ebp + pushl %ebx + pushl %edx + pushl %ecx + pushl %eax + + pushl %esp /* Pointer to structure on the stack */ + call x86_exception + pop %eax /* Drop the pointer */ + + popl %eax + popl %ecx + popl %edx + popl %ebx + popl %ebp /* Ignore saved %esp value */ + popl %ebp + popl %esi + popl %edi + + addl $8, %esp /* pop of the vector and error code */ + + iret + +#if CONFIG_GDB_STUB == 1 + + .globl gdb_stub_breakpoint +gdb_stub_breakpoint: + popl %eax /* Return address */ + pushfl + pushl %cs + pushl %eax /* Return address */ + pushl $0 /* No error code */ + pushl $32 /* vector 32 is user defined */ + jmp int_hand + +#endif + + .globl gdt, gdt_end, gdt_limit, idtarg + +gdt_limit = gdt_end - gdt - 1 /* compute the table limit */ +gdtaddr: + .word gdt_limit + .long gdt /* we know the offset */ + + .data + + /* This is the gdt for GCC part of coreboot. + * It is different from the gdt in ROMCC/ASM part of coreboot + * which is defined in entry32.inc + * + * When the machine is initially started, we use a very simple + * gdt from rom (that in entry32.inc) which only contains those + * entries we need for protected mode. + * + * When we're executing code from RAM, we want to do more complex + * stuff, like initializing PCI option roms in real mode, or doing + * a resume from a suspend to ram. + */ +gdt: + /* selgdt 0, unused */ + .word 0x0000, 0x0000 /* dummy */ + .byte 0x00, 0x00, 0x00, 0x00 + + /* selgdt 8, unused */ + .word 0x0000, 0x0000 /* dummy */ + .byte 0x00, 0x00, 0x00, 0x00 + + /* selgdt 0x10, flat code segment */ + .word 0xffff, 0x0000 + .byte 0x00, 0x9b, 0xcf, 0x00 /* G=1 and 0x0f, So we get 4Gbytes for limit */ + + /* selgdt 0x18, flat data segment */ + .word 0xffff, 0x0000 + .byte 0x00, 0x93, 0xcf, 0x00 + + /* selgdt 0x20, unused */ + .word 0x0000, 0x0000 /* dummy */ + .byte 0x00, 0x00, 0x00, 0x00 + + /* The next two entries are used for executing VGA option ROMs */ + + /* selgdt 0x28 16 bit 64k code at 0x00000000 */ + .word 0xffff, 0x0000 + .byte 0, 0x9a, 0, 0 + + /* selgdt 0x30 16 bit 64k data at 0x00000000 */ + .word 0xffff, 0x0000 + .byte 0, 0x92, 0, 0 + + /* The next two entries are used for ACPI S3 RESUME */ + + /* selgdt 0x38, flat data segment 16 bit */ + .word 0x0000, 0x0000 /* dummy */ + .byte 0x00, 0x93, 0x8f, 0x00 /* G=1 and 0x0f, So we get 4Gbytes for limit */ + + /* selgdt 0x40, flat code segment 16 bit */ + .word 0xffff, 0x0000 + .byte 0x00, 0x9b, 0x8f, 0x00 /* G=1 and 0x0f, So we get 4Gbytes for limit */ +gdt_end: + +idtarg: + .word _idt_end - _idt - 1 /* limit */ + .long _idt + .word 0 +_idt: + .fill 20, 8, 0 # idt is uninitialized +_idt_end: + + .previous +.code32 |