1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Copyright (C) 2018 ARM Limited
4 */
5 #ifndef __ASM_VDSO_GETTIMEOFDAY_H
6 #define __ASM_VDSO_GETTIMEOFDAY_H
7
8 #ifndef __ASSEMBLY__
9
10 #include <asm/alternative.h>
11 #include <asm/barrier.h>
12 #include <asm/unistd.h>
13 #include <asm/sysreg.h>
14
15 #define VDSO_HAS_CLOCK_GETRES 1
16
17 static __always_inline
18 int gettimeofday_fallback(struct __kernel_old_timeval *_tv,
19 struct timezone *_tz)
20 {
21 register struct timezone *tz asm("x1") = _tz;
22 register struct __kernel_old_timeval *tv asm("x0") = _tv;
23 register long ret asm ("x0");
24 register long nr asm("x8") = __NR_gettimeofday;
25
26 asm volatile(
27 " svc #0\n"
28 : "=r" (ret)
29 : "r" (tv), "r" (tz), "r" (nr)
30 : "memory");
31
32 return ret;
33 }
34
35 static __always_inline
36 long clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
37 {
38 register struct __kernel_timespec *ts asm("x1") = _ts;
39 register clockid_t clkid asm("x0") = _clkid;
40 register long ret asm ("x0");
41 register long nr asm("x8") = __NR_clock_gettime;
42
43 asm volatile(
44 " svc #0\n"
45 : "=r" (ret)
46 : "r" (clkid), "r" (ts), "r" (nr)
47 : "memory");
48
49 return ret;
50 }
51
52 static __always_inline
53 int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
54 {
55 register struct __kernel_timespec *ts asm("x1") = _ts;
56 register clockid_t clkid asm("x0") = _clkid;
57 register long ret asm ("x0");
58 register long nr asm("x8") = __NR_clock_getres;
59
60 asm volatile(
61 " svc #0\n"
62 : "=r" (ret)
63 : "r" (clkid), "r" (ts), "r" (nr)
64 : "memory");
65
66 return ret;
67 }
68
69 static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
70 const struct vdso_data *vd)
71 {
72 u64 res;
73
74 /*
75 * Core checks for mode already, so this raced against a concurrent
76 * update. Return something. Core will do another round and then
77 * see the mode change and fallback to the syscall.
78 */
79 if (clock_mode == VDSO_CLOCKMODE_NONE)
80 return 0;
81
82 /*
83 * If FEAT_ECV is available, use the self-synchronizing counter.
84 * Otherwise the isb is required to prevent that the counter value
85 * is speculated.
86 */
87 asm volatile(
88 ALTERNATIVE("isb\n"
89 "mrs %0, cntvct_el0",
90 "nop\n"
91 __mrs_s("%0", SYS_CNTVCTSS_EL0),
92 ARM64_HAS_ECV)
93 : "=r" (res)
94 :
95 : "memory");
96
97 arch_counter_enforce_ordering(res);
98
99 return res;
100 }
101
102 static __always_inline
103 const struct vdso_data *__arch_get_vdso_data(void)
104 {
105 return _vdso_data;
106 }
107
108 #ifdef CONFIG_TIME_NS
109 static __always_inline
110 const struct vdso_data *__arch_get_timens_vdso_data(const struct vdso_data *vd)
111 {
112 return _timens_data;
113 }
114 #endif
115
116 #endif /* !__ASSEMBLY__ */
117
118 #endif /* __ASM_VDSO_GETTIMEOFDAY_H */
119
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.