/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Hibernation support for x86-64
 *
 * Copyright 2007 Rafael J. Wysocki <rjw@sisk.pl>
 * Copyright 2005 Andi Kleen <ak@suse.de>
 * Copyright 2004 Pavel Machek <pavel@suse.cz>
 *
 * swsusp_arch_resume must not use any stack or any nonlocal variables while
 * copying pages:
 *
 * Its rewriting one kernel image with another. What is stack in "old"
 * image could very well be data page in "new" image, and overwriting
 * your own stack under you is bad idea.
 */

        .text
#include <linux/linkage.h>
#include <asm/segment.h>
#include <asm/page_types.h>
#include <asm/asm-offsets.h>
#include <asm/processor-flags.h>
#include <asm/frame.h>
#include <asm/nospec-branch.h>

         /* code below belongs to the image kernel */
        .align PAGE_SIZE
SYM_FUNC_START(restore_registers)
        ENDBR
        /* go back to the original page tables */
        movq    %r9, %cr3

        /* Flush TLB, including "global" things (vmalloc) */
        movq    mmu_cr4_features(%rip), %rax
        movq    %rax, %rdx
        andq    $~(X86_CR4_PGE), %rdx
        movq    %rdx, %cr4;  # turn off PGE
        movq    %cr3, %rcx;  # flush TLB
        movq    %rcx, %cr3
        movq    %rax, %cr4;  # turn PGE back on

        /* We don't restore %rax, it must be 0 anyway */
        movq    $saved_context, %rax
        movq    pt_regs_sp(%rax), %rsp
        movq    pt_regs_bp(%rax), %rbp
        movq    pt_regs_si(%rax), %rsi
        movq    pt_regs_di(%rax), %rdi
        movq    pt_regs_bx(%rax), %rbx
        movq    pt_regs_cx(%rax), %rcx
        movq    pt_regs_dx(%rax), %rdx
        movq    pt_regs_r8(%rax), %r8
        movq    pt_regs_r9(%rax), %r9
        movq    pt_regs_r10(%rax), %r10
        movq    pt_regs_r11(%rax), %r11
        movq    pt_regs_r12(%rax), %r12
        movq    pt_regs_r13(%rax), %r13
        movq    pt_regs_r14(%rax), %r14
        movq    pt_regs_r15(%rax), %r15
        pushq   pt_regs_flags(%rax)
        popfq

        /* Saved in save_processor_state. */
        lgdt    saved_context_gdt_desc(%rax)

        xorl    %eax, %eax

        /* tell the hibernation core that we've just restored the memory */
        movq    %rax, in_suspend(%rip)

        RET
SYM_FUNC_END(restore_registers)

SYM_FUNC_START(swsusp_arch_suspend)
        movq    $saved_context, %rax
        movq    %rsp, pt_regs_sp(%rax)
        movq    %rbp, pt_regs_bp(%rax)
        movq    %rsi, pt_regs_si(%rax)
        movq    %rdi, pt_regs_di(%rax)
        movq    %rbx, pt_regs_bx(%rax)
        movq    %rcx, pt_regs_cx(%rax)
        movq    %rdx, pt_regs_dx(%rax)
        movq    %r8, pt_regs_r8(%rax)
        movq    %r9, pt_regs_r9(%rax)
        movq    %r10, pt_regs_r10(%rax)
        movq    %r11, pt_regs_r11(%rax)
        movq    %r12, pt_regs_r12(%rax)
        movq    %r13, pt_regs_r13(%rax)
        movq    %r14, pt_regs_r14(%rax)
        movq    %r15, pt_regs_r15(%rax)
        pushfq
        popq    pt_regs_flags(%rax)

        /* save cr3 */
        movq    %cr3, %rax
        movq    %rax, restore_cr3(%rip)

        FRAME_BEGIN
        call swsusp_save
        FRAME_END
        RET
SYM_FUNC_END(swsusp_arch_suspend)

SYM_FUNC_START(restore_image)
        /* prepare to jump to the image kernel */
        movq    restore_jump_address(%rip), %r8
        movq    restore_cr3(%rip), %r9

        /* prepare to switch to temporary page tables */
        movq    temp_pgt(%rip), %rax
        movq    mmu_cr4_features(%rip), %rbx

        /* prepare to copy image data to their original locations */
        movq    restore_pblist(%rip), %rdx

        /* jump to relocated restore code */
        movq    relocated_restore_code(%rip), %rcx
        ANNOTATE_RETPOLINE_SAFE
        jmpq    *%rcx
SYM_FUNC_END(restore_image)

        /* code below has been relocated to a safe page */
SYM_FUNC_START(core_restore_code)
        ENDBR
        /* switch to temporary page tables */
        movq    %rax, %cr3
        /* flush TLB */
        movq    %rbx, %rcx
        andq    $~(X86_CR4_PGE), %rcx
        movq    %rcx, %cr4;  # turn off PGE
        movq    %cr3, %rcx;  # flush TLB
        movq    %rcx, %cr3;
        movq    %rbx, %cr4;  # turn PGE back on
.Lloop:
        testq   %rdx, %rdx
        jz      .Ldone

        /* get addresses from the pbe and copy the page */
        movq    pbe_address(%rdx), %rsi
        movq    pbe_orig_address(%rdx), %rdi
        movq    $(PAGE_SIZE >> 3), %rcx
        rep movsq

        /* progress to the next pbe */
        movq    pbe_next(%rdx), %rdx
        jmp     .Lloop

.Ldone:
        /* jump to the restore_registers address from the image header */
        ANNOTATE_RETPOLINE_SAFE
        jmpq    *%r8
SYM_FUNC_END(core_restore_code)