Mark condition register 0 (cr0) as being clobbered by the inline asm in
get_cpu_clock(). Not doing this results in strange behaviour due to GCC
optimising away some checking. For example e.g:
$ ./fio examples/null.fio --output-format=json
time 5500 cycles_start=
8085227422910 <--- bad!
{
"fio version" : "fio-2.21-89-gb034",
<snip>
The extra output is due to the flag checking in dprint being removed
at higher optimisation levels.
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
" cmpwi %0,0;\n"
" beq- 90b;\n"
: "=r" (rval)
- : "i" (SPRN_TBRL));
+ : "i" (SPRN_TBRL)
+ : "cr0");
return rval;
}