Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/riscv/kernel/hibernate-asm.S
26424 views
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 <[email protected]>

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
 */

24
SYM_FUNC_START(__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

37
SYM_FUNC_END(__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
 */

45
SYM_FUNC_START(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

53
SYM_FUNC_END(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
 */

61
SYM_FUNC_START(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

76
SYM_FUNC_END(hibernate_core_restore_code)

77


78