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x86/vdso: Enforce 64bit clocksource

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All VDSO clock sources are TSC based and use CLOCKSOURCE_MASK(64). There is
no point in masking with all FF. Get rid of it and enforce the mask in the
sanity checker.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Florian Weimer <fweimer@redhat.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/20180917130707.151963007@linutronix.de
This commit is contained in:
Thomas Gleixner 2018-09-17 14:45:36 +02:00
parent 2a21ad571b
commit a51e996d48
2 changed files with 7 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/x86/entry/vdso/vclock_gettime.c
View file

@ -201,7 +201,7 @@ notrace static inline u64 vgetsns(int *mode)
#endif
else
return 0;
v = (cycles - gtod->cycle_last) & gtod->mask;
v = cycles - gtod->cycle_last;
return v * gtod->mult;
}

6
arch/x86/kernel/time.c
View file

@ -120,4 +120,10 @@ void clocksource_arch_init(struct clocksource *cs)
cs->name, cs->archdata.vclock_mode);
cs->archdata.vclock_mode = VCLOCK_NONE;
}
if (cs->mask != CLOCKSOURCE_MASK(64)) {
pr_warn("clocksource %s registered with invalid mask %016llx. Disabling vclock.\n",
cs->name, cs->mask);
cs->archdata.vclock_mode = VCLOCK_NONE;
}
}