diff options
Diffstat (limited to 'purgatory/arch/x86_64/setup-x86_64.S')
-rw-r--r-- | purgatory/arch/x86_64/setup-x86_64.S | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/purgatory/arch/x86_64/setup-x86_64.S b/purgatory/arch/x86_64/setup-x86_64.S new file mode 100644 index 0000000..95572d8 --- /dev/null +++ b/purgatory/arch/x86_64/setup-x86_64.S @@ -0,0 +1,76 @@ +/* + * purgatory: setup code + * + * Copyright (C) 2003,2004 Eric Biederman (ebiederm@xmission.com) + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include "arch/debug.h" + + +#undef i386 + + .text + .globl purgatory_start + .balign 16 +purgatory_start: + .code64 + + /* Load a gdt so I know what the segment registers are */ + lgdt gdt(%rip) + + /* load the data segments */ + movl $0x18, %eax /* data segment */ + movl %eax, %ds + movl %eax, %es + movl %eax, %ss + movl %eax, %fs + movl %eax, %gs + + /* In 64bit mode the code segment is meaningless */ + + movq 0(%rsp), %rax + movq %rax, jump_back_entry(%rip) + + /* Setup a stack */ + leaq lstack_end(%rip), %rsp + + /* Call the C code */ + call purgatory + jmp entry64 + + .section ".rodata" + .balign 16 +gdt: /* 0x00 unusable segment + * 0x08 unused + * so use them as the gdt ptr + */ + .word gdt_end - gdt - 1 + .quad gdt + .word 0, 0, 0 + + /* 0x10 4GB flat code segment */ + .word 0xFFFF, 0x0000, 0x9A00, 0x00AF + + /* 0x18 4GB flat data segment */ + .word 0xFFFF, 0x0000, 0x9200, 0x00CF +gdt_end: + + .bss + .balign 4096 +lstack: + .skip 4096 +lstack_end: + |