[RFC PATCH] powerpc/32: Switch VDSO to C implementation.
Christophe Leroy
christophe.leroy at c-s.fr
Sat Dec 21 05:24:22 AEDT 2019
Hi Thomas,
In do_hres(), I see:
cycles = __arch_get_hw_counter(vd->clock_mode);
ns = vdso_ts->nsec;
last = vd->cycle_last;
if (unlikely((s64)cycles < 0))
return -1;
__arch_get_hw_counter() returns a u64 values. On the PPC, this is read
from the timebase which is a 64 bits counter.
Why returning -1 if (s64)cycles < 0 ? Does it means we have to mask out
the most significant bit when reading the HW counter ?
Christophe
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