search for: update_vsyscall

...- CLOCK ids are set in stone > - CLOCK_THREAD_CPUTIME is never going to be supported in the VDSO so > the array slot 3 is unused > - CLOCK_TAI is id 11 which results in 3 when masked with 0x3 > > Add the mask to the basetime array lookup and set up the CLOCK_TAI base > time in update_vsyscall(). That?s... horrible. In an amazing way. Can you add BUILD_BUG_ON somewhere to assert that this actually works? > > The performance impact of the mask operation is within the noise. > > Signed-off-by: Thomas Gleixner <tglx at linutronix.de> > --- > arch/x86/entry/vdso/v...

...- CLOCK ids are set in stone > - CLOCK_THREAD_CPUTIME is never going to be supported in the VDSO so > the array slot 3 is unused > - CLOCK_TAI is id 11 which results in 3 when masked with 0x3 > > Add the mask to the basetime array lookup and set up the CLOCK_TAI base > time in update_vsyscall(). That?s... horrible. In an amazing way. Can you add BUILD_BUG_ON somewhere to assert that this actually works? > > The performance impact of the mask operation is within the noise. > > Signed-off-by: Thomas Gleixner <tglx at linutronix.de> > --- > arch/x86/entry/vdso/v...

...ake use of the fact that: - CLOCK ids are set in stone - CLOCK_THREAD_CPUTIME is never going to be supported in the VDSO so the array slot 3 is unused - CLOCK_TAI is id 11 which results in 3 when masked with 0x3 Add the mask to the basetime array lookup and set up the CLOCK_TAI base time in update_vsyscall(). The performance impact of the mask operation is within the noise. Signed-off-by: Thomas Gleixner <tglx at linutronix.de> --- arch/x86/entry/vdso/vclock_gettime.c | 2 +- arch/x86/entry/vsyscall/vsyscall_gtod.c | 4 ++++ arch/x86/include/asm/vgtod.h | 6 +++++- 3 f...

...> > - CLOCK_THREAD_CPUTIME is never going to be supported in the VDSO so > > the array slot 3 is unused > > - CLOCK_TAI is id 11 which results in 3 when masked with 0x3 > > > > Add the mask to the basetime array lookup and set up the CLOCK_TAI base > > time in update_vsyscall(). > > That?s... horrible. In an amazing way. Can you add BUILD_BUG_ON somewhere > to assert that this actually works? Sure, but changing any of the clock ids will cause more wreckage than that. Thanks, tglx

...OCK_THREAD_CPUTIME is never going to be supported in the VDSO so >>> the array slot 3 is unused >>> - CLOCK_TAI is id 11 which results in 3 when masked with 0x3 >>> >>> Add the mask to the basetime array lookup and set up the CLOCK_TAI base >>> time in update_vsyscall(). >> >> That?s... horrible. In an amazing way. Can you add BUILD_BUG_ON somewhere >> to assert that this actually works? > > Sure, but changing any of the clock ids will cause more wreckage than that. > I?m more concerned that we add a new one and break the magic mas...

...fier); /* must hold timekeeper_lock */ -static void timekeeping_update(struct timekeeper *tk, bool clearntp, bool mirror) +static void timekeeping_update(struct timekeeper *tk, unsigned action) { - if (clearntp) { + if (action & TK_CLEAR_NTP) { tk->ntp_error = 0; ntp_clear(); } update_vsyscall(tk); update_pvclock_gtod(tk); - if (mirror) + if (action & TK_MIRROR) memcpy(&shadow_timekeeper, &timekeeper, sizeof(timekeeper)); } @@ -508,7 +511,7 @@ int do_settimeofday(const struct timespec *tv) tk_set_xtime(tk, tv); - timekeeping_update(tk, true, true); + timekeepi...

Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() implementation, which extended the clockid switch case and added yet another slightly different copy of the same code. Especially the extended switch case is problematic as the compiler tends to generate a jump table which then requires to use retpolines. If jump tables are disabled it adds yet another conditional to the existing

Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() implementation, which extended the clockid switch case and added yet another slightly different copy of the same code. Especially the extended switch case is problematic as the compiler tends to generate a jump table which then requires to use retpolines. If jump tables are disabled it adds yet another conditional to the existing

Matt attempted to add CLOCK_TAI support to the VDSO clock_gettime() implementation, which extended the clockid switch case and added yet another slightly different copy of the same code. Especially the extended switch case is problematic as the compiler tends to generate a jump table which then requires to use retpolines. If jump tables are disabled it adds yet another conditional to the existing

From: David Vrabel <david.vrabel@citrix.com> The high resolution timer code gets notified of step changes to the system time with clock_was_set() or clock_was_set_delayed() calls. If other parts of the kernel require similar notification there is no clear place to hook into. Add a clock_was_set atomic notifier chain (clock_was_set_notifier_list) and call this in place of clock_was_set().