Book a Demo!
CoCalc Logo Icon
StoreFeaturesDocsShareSupportNewsAboutPoliciesSign UpSign In
torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/tools/arch/x86/include/asm/pvclock.h
29274 views
1
/* SPDX-License-Identifier: GPL-2.0 */

2
#ifndef _ASM_X86_PVCLOCK_H

3
#define _ASM_X86_PVCLOCK_H

4


5
#include <asm/barrier.h>

6
#include <asm/pvclock-abi.h>

7


8
/* some helper functions for xen and kvm pv clock sources */

9
u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);

10
u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);

11
void pvclock_set_flags(u8 flags);

12
unsigned long pvclock_tsc_khz(struct pvclock_vcpu_time_info *src);

13
void pvclock_resume(void);

14


15
void pvclock_touch_watchdogs(void);

16


17
static __always_inline

18
unsigned pvclock_read_begin(const struct pvclock_vcpu_time_info *src)

19
{

20
	unsigned version = src->version & ~1;

21
	/* Make sure that the version is read before the data. */

22
	rmb();

23
	return version;

24
}

25


26
static __always_inline

27
bool pvclock_read_retry(const struct pvclock_vcpu_time_info *src,

28
			unsigned version)

29
{

30
	/* Make sure that the version is re-read after the data. */

31
	rmb();

32
	return version != src->version;

33
}

34


35
/*

36
 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,

37
 * yielding a 64-bit result.

38
 */

39
static inline u64 pvclock_scale_delta(u64 delta, u32 mul_frac, int shift)

40
{

41
	u64 product;

42
#ifdef __i386__

43
	u32 tmp1, tmp2;

44
#else

45
	unsigned long tmp;

46
#endif

47


48
	if (shift < 0)

49
		delta >>= -shift;

50
	else

51
		delta <<= shift;

52


53
#ifdef __i386__

54
	__asm__ (

55
		"mul  %5       ; "

56
		"mov  %4,%%eax ; "

57
		"mov  %%edx,%4 ; "

58
		"mul  %5       ; "

59
		"xor  %5,%5    ; "

60
		"add  %4,%%eax ; "

61
		"adc  %5,%%edx ; "

62
		: "=A" (product), "=r" (tmp1), "=r" (tmp2)

63
		: "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );

64
#elif defined(__x86_64__)

65
	__asm__ (

66
		"mulq %[mul_frac] ; shrd $32, %[hi], %[lo]"

67
		: [lo]"=a"(product),

68
		  [hi]"=d"(tmp)

69
		: "0"(delta),

70
		  [mul_frac]"rm"((u64)mul_frac));

71
#else

72
#error implement me!

73
#endif

74


75
	return product;

76
}

77


78
static __always_inline

79
u64 __pvclock_read_cycles(const struct pvclock_vcpu_time_info *src, u64 tsc)

80
{

81
	u64 delta = tsc - src->tsc_timestamp;

82
	u64 offset = pvclock_scale_delta(delta, src->tsc_to_system_mul,

83
					     src->tsc_shift);

84
	return src->system_time + offset;

85
}

86


87
struct pvclock_vsyscall_time_info {

88
	struct pvclock_vcpu_time_info pvti;

89
} __attribute__((__aligned__(64)));

90


91
#define PVTI_SIZE sizeof(struct pvclock_vsyscall_time_info)

92


93
#ifdef CONFIG_PARAVIRT_CLOCK

94
void pvclock_set_pvti_cpu0_va(struct pvclock_vsyscall_time_info *pvti);

95
struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void);

96
#else

97
static inline struct pvclock_vsyscall_time_info *pvclock_get_pvti_cpu0_va(void)

98
{

99
	return NULL;

100
}

101
#endif

102


103
#endif /* _ASM_X86_PVCLOCK_H */

104


105