/* SPDX-License-Identifier: GPL-2.0-only */
        .text
#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/page_types.h>

# Copyright 2003, 2008 Pavel Machek <pavel@suse.cz

        .code32
        ALIGN

SYM_CODE_START(wakeup_pmode_return)
        movw    $__KERNEL_DS, %ax
        movw    %ax, %ss
        movw    %ax, %fs
        movw    %ax, %gs

        movw    $__USER_DS, %ax
        movw    %ax, %ds
        movw    %ax, %es

        # reload the gdt, as we need the full 32 bit address
        lidt    saved_idt
        lldt    saved_ldt
        ljmp    $(__KERNEL_CS), $1f
1:
        movl    %cr3, %eax
        movl    %eax, %cr3
        wbinvd

        # and restore the stack ... but you need gdt for this to work
        movl    saved_context_esp, %esp

        movl    %cs:saved_magic, %eax
        cmpl    $0x12345678, %eax
        jne     bogus_magic

        # jump to place where we left off
        movl    saved_eip, %eax
        jmp     *%eax
SYM_CODE_END(wakeup_pmode_return)

bogus_magic:
        jmp     bogus_magic



save_registers:
        sidt    saved_idt
        sldt    saved_ldt
        str     saved_tss

        leal    4(%esp), %eax
        movl    %eax, saved_context_esp
        movl    %ebx, saved_context_ebx
        movl    %ebp, saved_context_ebp
        movl    %esi, saved_context_esi
        movl    %edi, saved_context_edi
        pushfl
        popl    saved_context_eflags

        movl    $ret_point, saved_eip
        RET


restore_registers:
        movl    saved_context_ebp, %ebp
        movl    saved_context_ebx, %ebx
        movl    saved_context_esi, %esi
        movl    saved_context_edi, %edi
        pushl   saved_context_eflags
        popfl
        RET

SYM_CODE_START(do_suspend_lowlevel)
        call    save_processor_state
        call    save_registers
        pushl   $3
        call    x86_acpi_enter_sleep_state
        addl    $4, %esp

#       In case of S3 failure, we'll emerge here.  Jump
#       to ret_point to recover
        jmp     ret_point
        .p2align 4,,7
ret_point:
        call    restore_registers
        call    restore_processor_state
        RET
SYM_CODE_END(do_suspend_lowlevel)

.data
ALIGN
SYM_DATA(saved_magic,   .long 0)
saved_eip:              .long 0

# saved registers
saved_idt:      .long   0,0
saved_ldt:      .long   0
saved_tss:      .long   0