linux/arch/x86/include/asm/tsc.h
Andy Lutomirski 98d0ac38ca x86-64: Move vread_tsc and vread_hpet into the vDSO
The vsyscall page now consists entirely of trap instructions.

Cc: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Link: http://lkml.kernel.org/r/637648f303f2ef93af93bae25186e9a1bea093f5.1310639973.git.luto@mit.edu
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2011-07-14 17:57:05 -07:00

66 lines
1.3 KiB
C

/*
* x86 TSC related functions
*/
#ifndef _ASM_X86_TSC_H
#define _ASM_X86_TSC_H
#include <asm/processor.h>
#define NS_SCALE 10 /* 2^10, carefully chosen */
#define US_SCALE 32 /* 2^32, arbitralrily chosen */
/*
* Standard way to access the cycle counter.
*/
typedef unsigned long long cycles_t;
extern unsigned int cpu_khz;
extern unsigned int tsc_khz;
extern void disable_TSC(void);
static inline cycles_t get_cycles(void)
{
unsigned long long ret = 0;
#ifndef CONFIG_X86_TSC
if (!cpu_has_tsc)
return 0;
#endif
rdtscll(ret);
return ret;
}
static __always_inline cycles_t vget_cycles(void)
{
/*
* We only do VDSOs on TSC capable CPUs, so this shouldn't
* access boot_cpu_data (which is not VDSO-safe):
*/
#ifndef CONFIG_X86_TSC
if (!cpu_has_tsc)
return 0;
#endif
return (cycles_t)__native_read_tsc();
}
extern void tsc_init(void);
extern void mark_tsc_unstable(char *reason);
extern int unsynchronized_tsc(void);
extern int check_tsc_unstable(void);
extern unsigned long native_calibrate_tsc(void);
/*
* Boot-time check whether the TSCs are synchronized across
* all CPUs/cores:
*/
extern void check_tsc_sync_source(int cpu);
extern void check_tsc_sync_target(void);
extern int notsc_setup(char *);
extern void save_sched_clock_state(void);
extern void restore_sched_clock_state(void);
#endif /* _ASM_X86_TSC_H */