diff options
Diffstat (limited to 'purgatory/arch/x86_64/entry64.S')
| -rw-r--r-- | purgatory/arch/x86_64/entry64.S | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/purgatory/arch/x86_64/entry64.S b/purgatory/arch/x86_64/entry64.S new file mode 100644 index 0000000..e3223b7 --- /dev/null +++ b/purgatory/arch/x86_64/entry64.S @@ -0,0 +1,107 @@ +/* + * kexec: Linux boots Linux + * + * 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" + +.text +.code64 + .balign 16 + .globl entry64, entry64_regs +entry64: + /* Don't worry about special registers... */ + + /* Setup a gdt that should be preserved */ + 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 + + leaq stack_init(%rip), %rsp + pushq $0x10 /* CS */ + leaq new_cs_exit(%rip), %rax + pushq %rax + lretq +new_cs_exit: + + /* Load the registers */ + movq rax(%rip), %rax + movq rbx(%rip), %rbx + movq rcx(%rip), %rcx + movq rdx(%rip), %rdx + movq rsi(%rip), %rsi + movq rdi(%rip), %rdi + movq rsp(%rip), %rsp + movq rbp(%rip), %rbp + movq r8(%rip), %r8 + movq r9(%rip), %r9 + movq r10(%rip), %r10 + movq r11(%rip), %r11 + movq r12(%rip), %r12 + movq r13(%rip), %r13 + movq r14(%rip), %r14 + movq r15(%rip), %r15 + + /* Jump to the new code... */ + jmpq *rip(%rip) + + .section ".rodata" + .balign 4 +entry64_regs: +rax: .quad 0x00000000 +rbx: .quad 0x00000000 +rcx: .quad 0x00000000 +rdx: .quad 0x00000000 +rsi: .quad 0x00000000 +rdi: .quad 0x00000000 +rsp: .quad 0x00000000 +rbp: .quad 0x00000000 +r8: .quad 0x00000000 +r9: .quad 0x00000000 +r10: .quad 0x00000000 +r11: .quad 0x00000000 +r12: .quad 0x00000000 +r13: .quad 0x00000000 +r14: .quad 0x00000000 +r15: .quad 0x00000000 +rip: .quad entry32 + .size entry64_regs, . - entry64_regs + + .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: +stack: .quad 0, 0 +stack_init: |