linux-stable/arch/riscv/include/asm/suspend.h
Sia Jee Heng c031721001
RISC-V: Add arch functions to support hibernation/suspend-to-disk
Low level Arch functions were created to support hibernation.
swsusp_arch_suspend() relies code from __cpu_suspend_enter() to write
cpu state onto the stack, then calling swsusp_save() to save the memory
image.

Arch specific hibernation header is implemented and is utilized by the
arch_hibernation_header_restore() and arch_hibernation_header_save()
functions. The arch specific hibernation header consists of satp, hartid,
and the cpu_resume address. The kernel built version is also need to be
saved into the hibernation image header to making sure only the same
kernel is restore when resume.

swsusp_arch_resume() creates a temporary page table that covering only
the linear map. It copies the restore code to a 'safe' page, then start
to restore the memory image. Once completed, it restores the original
kernel's page table. It then calls into __hibernate_cpu_resume()
to restore the CPU context. Finally, it follows the normal hibernation
path back to the hibernation core.

To enable hibernation/suspend to disk into RISCV, the below config
need to be enabled:
- CONFIG_HIBERNATION
- CONFIG_ARCH_HIBERNATION_HEADER
- CONFIG_ARCH_HIBERNATION_POSSIBLE

Signed-off-by: Sia Jee Heng <jeeheng.sia@starfivetech.com>
Reviewed-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
Reviewed-by: Mason Huo <mason.huo@starfivetech.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230330064321.1008373-5-jeeheng.sia@starfivetech.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
2023-04-29 11:25:13 -07:00

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1.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (c) 2021 Western Digital Corporation or its affiliates.
* Copyright (c) 2022 Ventana Micro Systems Inc.
*/
#ifndef _ASM_RISCV_SUSPEND_H
#define _ASM_RISCV_SUSPEND_H
#include <asm/ptrace.h>
struct suspend_context {
/* Saved and restored by low-level functions */
struct pt_regs regs;
/* Saved and restored by high-level functions */
unsigned long scratch;
unsigned long tvec;
unsigned long ie;
#ifdef CONFIG_MMU
unsigned long satp;
#endif
};
/*
* Used by hibernation core and cleared during resume sequence
*/
extern int in_suspend;
/* Low-level CPU suspend entry function */
int __cpu_suspend_enter(struct suspend_context *context);
/* High-level CPU suspend which will save context and call finish() */
int cpu_suspend(unsigned long arg,
int (*finish)(unsigned long arg,
unsigned long entry,
unsigned long context));
/* Low-level CPU resume entry function */
int __cpu_resume_enter(unsigned long hartid, unsigned long context);
/* Used to save and restore the CSRs */
void suspend_save_csrs(struct suspend_context *context);
void suspend_restore_csrs(struct suspend_context *context);
/* Low-level API to support hibernation */
int swsusp_arch_suspend(void);
int swsusp_arch_resume(void);
int arch_hibernation_header_save(void *addr, unsigned int max_size);
int arch_hibernation_header_restore(void *addr);
int __hibernate_cpu_resume(void);
/* Used to resume on the CPU we hibernated on */
int hibernate_resume_nonboot_cpu_disable(void);
asmlinkage void hibernate_restore_image(unsigned long resume_satp, unsigned long satp_temp,
unsigned long cpu_resume);
asmlinkage int hibernate_core_restore_code(void);
#endif