106 lines
2.1 KiB
C
106 lines
2.1 KiB
C
#ifndef _ASM_X86_VGTOD_H
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#define _ASM_X86_VGTOD_H
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#include <linux/compiler.h>
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#include <linux/clocksource.h>
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#ifdef BUILD_VDSO32_64
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typedef u64 gtod_long_t;
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#else
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typedef unsigned long gtod_long_t;
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#endif
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/*
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* vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time
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* so be carefull by modifying this structure.
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*/
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struct vsyscall_gtod_data {
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unsigned seq;
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int vclock_mode;
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cycle_t cycle_last;
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cycle_t mask;
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u32 mult;
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u32 shift;
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/* open coded 'struct timespec' */
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u64 wall_time_snsec;
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gtod_long_t wall_time_sec;
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gtod_long_t monotonic_time_sec;
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u64 monotonic_time_snsec;
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gtod_long_t wall_time_coarse_sec;
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gtod_long_t wall_time_coarse_nsec;
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gtod_long_t monotonic_time_coarse_sec;
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gtod_long_t monotonic_time_coarse_nsec;
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int tz_minuteswest;
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int tz_dsttime;
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};
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extern struct vsyscall_gtod_data vsyscall_gtod_data;
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extern int vclocks_used;
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static inline bool vclock_was_used(int vclock)
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{
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return READ_ONCE(vclocks_used) & (1 << vclock);
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}
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static inline unsigned gtod_read_begin(const struct vsyscall_gtod_data *s)
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{
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unsigned ret;
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repeat:
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ret = ACCESS_ONCE(s->seq);
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if (unlikely(ret & 1)) {
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cpu_relax();
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goto repeat;
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}
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smp_rmb();
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return ret;
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}
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static inline int gtod_read_retry(const struct vsyscall_gtod_data *s,
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unsigned start)
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{
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smp_rmb();
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return unlikely(s->seq != start);
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}
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static inline void gtod_write_begin(struct vsyscall_gtod_data *s)
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{
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++s->seq;
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smp_wmb();
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}
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static inline void gtod_write_end(struct vsyscall_gtod_data *s)
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{
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smp_wmb();
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++s->seq;
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}
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#ifdef CONFIG_X86_64
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#define VGETCPU_CPU_MASK 0xfff
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static inline unsigned int __getcpu(void)
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{
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unsigned int p;
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/*
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* Load per CPU data from GDT. LSL is faster than RDTSCP and
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* works on all CPUs. This is volatile so that it orders
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* correctly wrt barrier() and to keep gcc from cleverly
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* hoisting it out of the calling function.
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*
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* If RDPID is available, use it.
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*/
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alternative_io ("lsl %[seg],%[p]",
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".byte 0xf3,0x0f,0xc7,0xf8", /* RDPID %eax/rax */
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X86_FEATURE_RDPID,
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[p] "=a" (p), [seg] "r" (__PER_CPU_SEG));
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return p;
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}
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#endif /* CONFIG_X86_64 */
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#endif /* _ASM_X86_VGTOD_H */
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