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| author | Will Deacon <will.deacon@arm.com> | 2012-11-29 22:33:29 +0000 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2012-12-05 11:20:03 +0000 |
| commit | 45a7905fc48f6079932e77d64237cf7f008db5f4 (patch) | |
| tree | 93b60ea0b2c3daf94b50dfa3125b2a3c59a0ff1b /arch/arm64/kernel/vdso.c | |
| parent | d91fb5c2677db90460611fce72e6a0af8f6c2a73 (diff) | |
| download | op-kernel-dev-45a7905fc48f6079932e77d64237cf7f008db5f4.zip op-kernel-dev-45a7905fc48f6079932e77d64237cf7f008db5f4.tar.gz | |
arm64: vdso: defer shifting of nanosecond component of timespec
Shifting the nanosecond component of the computed timespec early can
lead to sub-ns inaccuracies when using the truncated value as input to
further arithmetic for things like conversions to monotonic time.
This patch defers the timespec shifting until after the final value has
been computed.
Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/vdso.c')
| -rw-r--r-- | arch/arm64/kernel/vdso.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c index ba45794..c958cb8 100644 --- a/arch/arm64/kernel/vdso.c +++ b/arch/arm64/kernel/vdso.c @@ -239,7 +239,7 @@ void update_vsyscall(struct timekeeper *tk) if (!use_syscall) { vdso_data->cs_cycle_last = tk->clock->cycle_last; vdso_data->xtime_clock_sec = tk->xtime_sec; - vdso_data->xtime_clock_nsec = tk->xtime_nsec >> tk->shift; + vdso_data->xtime_clock_nsec = tk->xtime_nsec; vdso_data->cs_mult = tk->mult; vdso_data->cs_shift = tk->shift; vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec; |
