| Date | Fri, 07 Feb 2020 13:38:50 +0100 | From | Thomas Gleixner <> | Subject | [patch V2 03/17] lib/vdso: Allow the high resolution parts to be compiled out |
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From: Thomas Gleixner <tglx@linutronix.de>
If the architecture knows at compile time that there is no VDSO capable clocksource supported it makes sense to optimize the guts of the high resolution parts of the VDSO out at build time. Add a helper function to check whether the VDSO should be high resolution capable and provide a stub which can be overridden by an architecture.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
--- lib/vdso/gettimeofday.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
--- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -38,6 +38,13 @@ u64 vdso_calc_delta(u64 cycles, u64 last } #endif +#ifndef __arch_vdso_hres_capable +static inline bool __arch_vdso_hres_capable(void) +{ + return true; +} +#endif + #ifdef CONFIG_TIME_NS static int do_hres_timens(const struct vdso_data *vdns, clockid_t clk, struct __kernel_timespec *ts) @@ -101,6 +108,10 @@ static __always_inline int do_hres(const u64 cycles, last, sec, ns; u32 seq; + /* Allows to compile the high resolution parts out */ + if (!__arch_vdso_hres_capable()) + return -1; + do { /* * Open coded to handle VCLOCK_TIMENS. Time namespace
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