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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Hibernation low level support for RISCV.
*
* Copyright (C) 2023 StarFive Technology Co., Ltd.
*
* Author: Jee Heng Sia <jeeheng.sia@starfivetech.com>
*/
#include <asm/asm.h>
#include <asm/asm-offsets.h>
#include <asm/assembler.h>
#include <asm/csr.h>
#include <linux/linkage.h>
/*
* int __hibernate_cpu_resume(void)
* Switch back to the hibernated image's page table prior to restoring the CPU
* context.
*
* Always returns 0
*/
ENTRY(__hibernate_cpu_resume)
/* switch to hibernated image's page table. */
csrw CSR_SATP, s0
sfence.vma
REG_L a0, hibernate_cpu_context
suspend_restore_csrs
suspend_restore_regs
/* Return zero value. */
mv a0, zero
ret
END(__hibernate_cpu_resume)
/*
* Prepare to restore the image.
* a0: satp of saved page tables.
* a1: satp of temporary page tables.
* a2: cpu_resume.
*/
ENTRY(hibernate_restore_image)
mv s0, a0
mv s1, a1
mv s2, a2
REG_L s4, restore_pblist
REG_L a1, relocated_restore_code
jalr a1
END(hibernate_restore_image)
/*
* The below code will be executed from a 'safe' page.
* It first switches to the temporary page table, then starts to copy the pages
* back to the original memory location. Finally, it jumps to __hibernate_cpu_resume()
* to restore the CPU context.
*/
ENTRY(hibernate_core_restore_code)
/* switch to temp page table. */
csrw satp, s1
sfence.vma
.Lcopy:
/* The below code will restore the hibernated image. */
REG_L a1, HIBERN_PBE_ADDR(s4)
REG_L a0, HIBERN_PBE_ORIG(s4)
copy_page a0, a1
REG_L s4, HIBERN_PBE_NEXT(s4)
bnez s4, .Lcopy
jalr s2
END(hibernate_core_restore_code)
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