1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Hibernation low level support for RISCV. 4 * 5 * Copyright (C) 2023 StarFive Technology Co., Ltd. 6 * 7 * Author: Jee Heng Sia <jeeheng.sia@starfivetech.com> 8 */ 9 10#include <asm/asm.h> 11#include <asm/asm-offsets.h> 12#include <asm/assembler.h> 13#include <asm/csr.h> 14 15#include <linux/linkage.h> 16 17/* 18 * int __hibernate_cpu_resume(void) 19 * Switch back to the hibernated image's page table prior to restoring the CPU 20 * context. 21 * 22 * Always returns 0 23 */ 24ENTRY(__hibernate_cpu_resume) 25 /* switch to hibernated image's page table. */ 26 csrw CSR_SATP, s0 27 sfence.vma 28 29 REG_L a0, hibernate_cpu_context 30 31 suspend_restore_regs 32 33 /* Return zero value. */ 34 mv a0, zero 35 36 ret 37END(__hibernate_cpu_resume) 38 39/* 40 * Prepare to restore the image. 41 * a0: satp of saved page tables. 42 * a1: satp of temporary page tables. 43 * a2: cpu_resume. 44 */ 45ENTRY(hibernate_restore_image) 46 mv s0, a0 47 mv s1, a1 48 mv s2, a2 49 REG_L s4, restore_pblist 50 REG_L a1, relocated_restore_code 51 52 jr a1 53END(hibernate_restore_image) 54 55/* 56 * The below code will be executed from a 'safe' page. 57 * It first switches to the temporary page table, then starts to copy the pages 58 * back to the original memory location. Finally, it jumps to __hibernate_cpu_resume() 59 * to restore the CPU context. 60 */ 61ENTRY(hibernate_core_restore_code) 62 /* switch to temp page table. */ 63 csrw satp, s1 64 sfence.vma 65.Lcopy: 66 /* The below code will restore the hibernated image. */ 67 REG_L a1, HIBERN_PBE_ADDR(s4) 68 REG_L a0, HIBERN_PBE_ORIG(s4) 69 70 copy_page a0, a1 71 72 REG_L s4, HIBERN_PBE_NEXT(s4) 73 bnez s4, .Lcopy 74 75 jr s2 76END(hibernate_core_restore_code) 77