diff options
Diffstat (limited to 'arch/x86/entry/vsyscall/vsyscall_gtod.c')
| -rw-r--r-- | arch/x86/entry/vsyscall/vsyscall_gtod.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/arch/x86/entry/vsyscall/vsyscall_gtod.c b/arch/x86/entry/vsyscall/vsyscall_gtod.c new file mode 100644 index 000000000..e1216dd95 --- /dev/null +++ b/arch/x86/entry/vsyscall/vsyscall_gtod.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE + * Copyright 2003 Andi Kleen, SuSE Labs. + * + * Modified for x86 32 bit architecture by + * Stefani Seibold <stefani@seibold.net> + * sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany + * + * 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/timekeeper_internal.h> +#include <asm/vgtod.h> +#include <asm/vvar.h> + +int vclocks_used __read_mostly; + +DEFINE_VVAR(struct vsyscall_gtod_data, vsyscall_gtod_data); + +void update_vsyscall_tz(void) +{ + vsyscall_gtod_data.tz_minuteswest = sys_tz.tz_minuteswest; + vsyscall_gtod_data.tz_dsttime = sys_tz.tz_dsttime; +} + +void update_vsyscall(struct timekeeper *tk) +{ + int vclock_mode = tk->tkr_mono.clock->archdata.vclock_mode; + struct vsyscall_gtod_data *vdata = &vsyscall_gtod_data; + + /* Mark the new vclock used. */ + BUILD_BUG_ON(VCLOCK_MAX >= 32); + WRITE_ONCE(vclocks_used, READ_ONCE(vclocks_used) | (1 << vclock_mode)); + + gtod_write_begin(vdata); + + /* copy vsyscall data */ + vdata->vclock_mode = vclock_mode; + vdata->cycle_last = tk->tkr_mono.cycle_last; + vdata->mask = tk->tkr_mono.mask; + vdata->mult = tk->tkr_mono.mult; + vdata->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 + + ((u64)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++; + } + + gtod_write_end(vdata); +} |