/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2003,2004  Eric Biederman (ebiederm@xmission.com)
 * Copyright (C) 2014  Red Hat Inc.

 * Author(s): Vivek Goyal <vgoyal@redhat.com>
 *
 * This code has been taken from kexec-tools.
 */

#include <linux/linkage.h>

        .text
        .balign 16
        .code64

SYM_CODE_START(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)
SYM_CODE_END(entry64)

        .section ".rodata"
        .balign 4
SYM_DATA_START(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
SYM_DATA_END(entry64_regs)

        /* GDT */
        .section ".rodata"
        .balign 16
SYM_DATA_START_LOCAL(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
SYM_DATA_END_LABEL(gdt, SYM_L_LOCAL, gdt_end)

SYM_DATA_START_LOCAL(stack)
        .quad   0, 0
SYM_DATA_END_LABEL(stack, SYM_L_LOCAL, stack_init)