| /* head.S for bootstub to load protected mode kernel |
| * Copyright (C) 2008 Alek Du <alek.du@intel.com> |
| * |
| * Note. When FW hand-off control to bootstub, the CPU is already in protected |
| * Mode with 1. GDT(8)=4G GDT(10)=4G |
| * 2. CS=8, DS=ES=FS=GS=10 |
| * 3. Paging mode disabled |
| * 4. Interrupt ENABLED |
| */ |
| |
| /* When bootstub get control, the memory map in DRAM is like: |
| * ~ ~ |
| * 0x102000 | initrd | initrd will move to highest memory otherwise |
| *+bzImage size +-----------------------+ bzImage uncompressing will destory it |
| * | bzImage | |
| * 0x102000 +-----------------------+ |
| * | boot stub | |
| * 0x101000 +-----------------------+ |
| * | free space | |
| * | used as stack | |
| * 0x10010c +-----------------------+ |
| * | initrd size | MIC need to fill it according to bzImage size |
| * 0x100108 +-----------------------+ |
| * | bzImage size | MIC need to fill it according to initrd size |
| * 0x100104 +-----------------------+ |
| * | mem size | MIC need to fill it |
| * 0x100100 +-----------------------+ |
| * | kernel cmdline | MIC need to fill it |
| * 0x100000 +-----------------------+ |
| */ |
| |
| #include "bootstub.h" |
| |
| .text |
| |
| .section ".text.head","ax",@progbits |
| .globl _start |
| |
| _start: |
| cld |
| cli |
| /* setup stack, because we are heading off to "C" */ |
| movl $STACK_OFFSET, %esp |
| /* after call main, GDT was set (0x10 and 0x18) IDT was clear |
| * eax will store 32bit entry of bzImage |
| */ |
| calll main |
| /* DS=ES=FS=GS=10 */ |
| movl $__BOOT_DS, %ebx |
| movl %ebx, %ds |
| movl %ebx, %es |
| movl %ebx, %fs |
| movl %ebx, %gs |
| movl %ebx, %ss |
| ljmp $__BOOT_CS,$1f |
| 1: |
| /* tell kernel where is boot_param */ |
| movl $(BOOT_PARAMS_OFFSET), %esi |
| xor %ebp, %ebp |
| xor %edi, %edi |
| xor %ebx, %ebx |
| |
| jmpl *%eax # Jump to the 32-bit entrypoint |
| |
