On Tue, 15 Jan 2019, Vincenzo Frascino wrote:
> +/*
> + * There is one vdso_timestamp object in vvar for each vDSO-accelerated
> + * clock_id. For high-resolution clocks, this encodes the time
> + * corresponding to vdso_data.cycle_last. For coarse clocks this encodes
> + * the actual time.
> + *
> + * To be noticed that nsec is left-shifted by vdso_data.shift.
This is only true for highres clocks. For coarse the nsec value is not
shifted.
> + */
> +struct vdso_timestamp {
> + u64 sec;
> + u64 nsec;
> +};
> +
> +/*
> + * vdso_data will be accessed by 32 and 64 bit code at the same time
> + * so we should be careful before modifying this structure.
> + */
> +struct vdso_data {
> + u32 seq; /* Timebase sequence counter */
> +
> + s32 clock_mode;
> + u64 cycle_last; /* Timebase at clocksource init */
> + u64 mask; /* Clocksource mask (mono = raw) */
mono = raw? This is broken. The VDSO cannot define time different from the
regular syscall interfaces.
Thanks,
tglx
