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Kernel and Embedded Linux
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/* * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE * Copyright 2003 Andi Kleen, SuSE Labs. * * Thanks to hpa@transmeta.com for some useful hint. * Special thanks to Ingo Molnar for his early experience with * a different vsyscall implementation for Linux/IA32 and for the name. */ #include <linux/seqlock.h> #include <linux/time.h> #include <linux/timekeeper_internal.h> #include <asm/vvar.h> void update_vsyscall_tz(void) { if (unlikely(vvar_data == NULL)) return; vvar_data->tz_minuteswest = sys_tz.tz_minuteswest; vvar_data->tz_dsttime = sys_tz.tz_dsttime; } void update_vsyscall(struct timekeeper *tk) { struct vvar_data *vdata = vvar_data; if (unlikely(vdata == NULL)) return; vvar_write_begin(vdata); vdata->vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode; vdata->clock.cycle_last = tk->tkr_mono.cycle_last; vdata->clock.mask = tk->tkr_mono.mask; vdata->clock.mult = tk->tkr_mono.mult; vdata->clock.shift = tk->tkr_mono.shift; vdata->wall_time_sec = tk->xtime_sec; vdata->wall_time_snsec = tk->tkr_mono.xtime_nsec; vdata->monotonic_time_sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; vdata->monotonic_time_snsec = tk->tkr_mono.xtime_nsec + (tk->wall_to_monotonic.tv_nsec << tk->tkr_mono.shift); while (vdata->monotonic_time_snsec >= (((u64)NSEC_PER_SEC) << tk->tkr_mono.shift)) { vdata->monotonic_time_snsec -= ((u64)NSEC_PER_SEC) << tk->tkr_mono.shift; vdata->monotonic_time_sec++; } vdata->wall_time_coarse_sec = tk->xtime_sec; vdata->wall_time_coarse_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift); vdata->monotonic_time_coarse_sec = vdata->wall_time_coarse_sec + tk->wall_to_monotonic.tv_sec; vdata->monotonic_time_coarse_nsec = vdata->wall_time_coarse_nsec + tk->wall_to_monotonic.tv_nsec; while (vdata->monotonic_time_coarse_nsec >= NSEC_PER_SEC) { vdata->monotonic_time_coarse_nsec -= NSEC_PER_SEC; vdata->monotonic_time_coarse_sec++; } vvar_write_end(vdata); }