| /* |
| * This file is part of the coreboot project. |
| * |
| * Copyright (C) 2009 Rudolf Marek <r.marek@assembler.cz> |
| * Copyright (C) 2009 coresystems GmbH |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; version 2 of the License. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #define WAKEUP_BASE 0x600 |
| #define RELOCATED(x) (x - __wakeup + WAKEUP_BASE) |
| |
| /* CR0 bits */ |
| #define PE (1 << 0) |
| |
| #ifdef __x86_64__ |
| .code64 |
| #else |
| .code32 |
| #endif |
| |
| .globl __wakeup |
| __wakeup: |
| #ifdef __x86_64__ |
| xor %rax,%rax |
| mov %ss, %ax |
| push %rax |
| mov %rsp, %rax |
| add $8, %rax |
| push %rax |
| pushfq |
| push $0x10 |
| lea 3(%rip), %rax |
| push %rax |
| iretq |
| |
| .code32 |
| |
| /* disable paging */ |
| mov %cr0, %eax |
| btc $31, %eax |
| mov %eax, %cr0 |
| |
| /* disable long mode */ |
| mov $0xC0000080, %ecx |
| rdmsr |
| btc $8, %eax |
| wrmsr |
| #endif |
| /* First prepare the jmp to the resume vector */ |
| mov 0x4(%esp), %eax /* vector */ |
| /* last 4 bits of linear addr are taken as offset */ |
| andw $0x0f, %ax |
| movw %ax, (__wakeup_offset) |
| mov 0x4(%esp), %eax |
| /* the rest is taken as segment */ |
| shr $4, %eax |
| movw %ax, (__wakeup_segment) |
| |
| /* Activate the right segment descriptor real mode. */ |
| ljmp $0x28, $RELOCATED(1f) |
| 1: |
| .code16 |
| /* 16 bit code from here on... */ |
| |
| /* Load the segment registers w/ properly configured |
| * segment descriptors. They will retain these |
| * configurations (limits, writability, etc.) once |
| * protected mode is turned off. |
| */ |
| mov $0x30, %ax |
| mov %ax, %ds |
| mov %ax, %es |
| mov %ax, %fs |
| mov %ax, %gs |
| mov %ax, %ss |
| |
| /* Turn off protection */ |
| movl %cr0, %eax |
| andl $~PE, %eax |
| movl %eax, %cr0 |
| |
| /* Now really going into real mode */ |
| ljmp $0, $RELOCATED(1f) |
| 1: |
| movw $0x0, %ax |
| movw %ax, %ds |
| movw %ax, %es |
| movw %ax, %ss |
| movw %ax, %fs |
| movw %ax, %gs |
| |
| /* This is a FAR JMP to the OS waking vector. The C code changed |
| * the address to be correct. |
| */ |
| .byte 0xea |
| |
| __wakeup_offset = RELOCATED(.) |
| .word 0x0000 |
| |
| __wakeup_segment = RELOCATED(.) |
| .word 0x0000 |
| |
| .globl __wakeup_size |
| __wakeup_size: |
| .long . - __wakeup |
