1#ifndef _ASM_X86_VGTOD_H
  2#define _ASM_X86_VGTOD_H
  3
 
 
 
 
 
  4#include <linux/compiler.h>
  5#include <linux/clocksource.h>
 
 
 
 
  6
  7#ifdef BUILD_VDSO32_64
  8typedef u64 gtod_long_t;
  9#else
 10typedef unsigned long gtod_long_t;
 11#endif
 12/*
 13 * vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time
 14 * so be carefull by modifying this structure.
 15 */
 16struct vsyscall_gtod_data {
 17	unsigned seq;
 18
 19	int vclock_mode;
 20	u64	cycle_last;
 21	u64	mask;
 22	u32	mult;
 23	u32	shift;
 24
 25	/* open coded 'struct timespec' */
 26	u64		wall_time_snsec;
 27	gtod_long_t	wall_time_sec;
 28	gtod_long_t	monotonic_time_sec;
 29	u64		monotonic_time_snsec;
 30	gtod_long_t	wall_time_coarse_sec;
 31	gtod_long_t	wall_time_coarse_nsec;
 32	gtod_long_t	monotonic_time_coarse_sec;
 33	gtod_long_t	monotonic_time_coarse_nsec;
 34
 35	int		tz_minuteswest;
 36	int		tz_dsttime;
 37};
 38extern struct vsyscall_gtod_data vsyscall_gtod_data;
 39
 40extern int vclocks_used;
 41static inline bool vclock_was_used(int vclock)
 42{
 43	return READ_ONCE(vclocks_used) & (1 << vclock);
 44}
 45
 46static inline unsigned gtod_read_begin(const struct vsyscall_gtod_data *s)
 47{
 48	unsigned ret;
 49
 50repeat:
 51	ret = ACCESS_ONCE(s->seq);
 52	if (unlikely(ret & 1)) {
 53		cpu_relax();
 54		goto repeat;
 55	}
 56	smp_rmb();
 57	return ret;
 58}
 59
 60static inline int gtod_read_retry(const struct vsyscall_gtod_data *s,
 61					unsigned start)
 62{
 63	smp_rmb();
 64	return unlikely(s->seq != start);
 65}
 66
 67static inline void gtod_write_begin(struct vsyscall_gtod_data *s)
 68{
 69	++s->seq;
 70	smp_wmb();
 71}
 72
 73static inline void gtod_write_end(struct vsyscall_gtod_data *s)
 74{
 75	smp_wmb();
 76	++s->seq;
 77}
 78
 79#ifdef CONFIG_X86_64
 80
 81#define VGETCPU_CPU_MASK 0xfff
 82
 83static inline unsigned int __getcpu(void)
 84{
 85	unsigned int p;
 86
 87	/*
 88	 * Load per CPU data from GDT.  LSL is faster than RDTSCP and
 89	 * works on all CPUs.  This is volatile so that it orders
 90	 * correctly wrt barrier() and to keep gcc from cleverly
 91	 * hoisting it out of the calling function.
 92	 *
 93	 * If RDPID is available, use it.
 94	 */
 95	alternative_io ("lsl %[p],%[seg]",
 96			".byte 0xf3,0x0f,0xc7,0xf8", /* RDPID %eax/rax */
 97			X86_FEATURE_RDPID,
 98			[p] "=a" (p), [seg] "r" (__PER_CPU_SEG));
 99
100	return p;
101}
102
103#endif /* CONFIG_X86_64 */
104
105#endif /* _ASM_X86_VGTOD_H */

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _ASM_X86_VGTOD_H
 3#define _ASM_X86_VGTOD_H
 4
 5/*
 6 * This check is required to prevent ARCH=um to include
 7 * unwanted headers.
 8 */
 9#ifdef CONFIG_GENERIC_GETTIMEOFDAY
10#include <linux/compiler.h>
11#include <asm/clocksource.h>
12#include <vdso/datapage.h>
13#include <vdso/helpers.h>
14
15#include <uapi/linux/time.h>
16
17#ifdef BUILD_VDSO32_64
18typedef u64 gtod_long_t;
19#else
20typedef unsigned long gtod_long_t;
21#endif
22#endif /* CONFIG_GENERIC_GETTIMEOFDAY */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
23
24#endif /* _ASM_X86_VGTOD_H */