forked from mirrors/linux
81fb8736dd
clock_getres() in the vDSO library has to preserve the same behaviour
of posix_get_hrtimer_res().
In particular, posix_get_hrtimer_res() does:
sec = 0;
ns = hrtimer_resolution;
where 'hrtimer_resolution' depends on whether or not high resolution
timers are enabled, which is a runtime decision.
The vDSO incorrectly returns the constant CLOCK_REALTIME_RES. Fix this
by exposing 'hrtimer_resolution' in the vDSO datapage and returning that
instead.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
[will: Use WRITE_ONCE(), move adr off COARSE path, renumber labels, use 'w' reg]
Signed-off-by: Will Deacon <will.deacon@arm.com>
48 lines
1.5 KiB
C
48 lines
1.5 KiB
C
/*
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* Copyright (C) 2012 ARM Limited
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ASM_VDSO_DATAPAGE_H
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#define __ASM_VDSO_DATAPAGE_H
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#ifdef __KERNEL__
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#ifndef __ASSEMBLY__
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struct vdso_data {
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__u64 cs_cycle_last; /* Timebase at clocksource init */
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__u64 raw_time_sec; /* Raw time */
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__u64 raw_time_nsec;
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__u64 xtime_clock_sec; /* Kernel time */
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__u64 xtime_clock_nsec;
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__u64 xtime_coarse_sec; /* Coarse time */
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__u64 xtime_coarse_nsec;
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__u64 wtm_clock_sec; /* Wall to monotonic time */
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__u64 wtm_clock_nsec;
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__u32 tb_seq_count; /* Timebase sequence counter */
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/* cs_* members must be adjacent and in this order (ldp accesses) */
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__u32 cs_mono_mult; /* NTP-adjusted clocksource multiplier */
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__u32 cs_shift; /* Clocksource shift (mono = raw) */
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__u32 cs_raw_mult; /* Raw clocksource multiplier */
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__u32 tz_minuteswest; /* Whacky timezone stuff */
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__u32 tz_dsttime;
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__u32 use_syscall;
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__u32 hrtimer_res;
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};
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#endif /* !__ASSEMBLY__ */
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#endif /* __KERNEL__ */
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#endif /* __ASM_VDSO_DATAPAGE_H */
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