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entry64.S
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/*
* Copyright (C) 2003,2004 Eric Biederman ([email protected])
* Copyright (C) 2014 Red Hat Inc.
* Author(s): Vivek Goyal <[email protected]>
*
* This code has been taken from kexec-tools.
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*/
.text
.balign 16
.code64
.globl entry64, entry64_regs
entry64:
/* 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
/* Setup new stack */
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 0x0
rcx: .quad 0x0
rdx: .quad 0x0
rbx: .quad 0x0
rsp: .quad 0x0
rbp: .quad 0x0
rsi: .quad 0x0
rdi: .quad 0x0
r8: .quad 0x0
r9: .quad 0x0
r10: .quad 0x0
r11: .quad 0x0
r12: .quad 0x0
r13: .quad 0x0
r14: .quad 0x0
r15: .quad 0x0
rip: .quad 0x0
.size entry64_regs, . - entry64_regs
/* GDT */
.section ".rodata"
.balign 16
gdt:
/* 0x00 unusable segment
* 0x08 unused
* so use them as 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: