The current (2bfe01e) torvalds git tree fails to build with the following error
arch/powerpc/kernel/time.c: In function ‘running_clock’:
arch/powerpc/kernel/time.c:712:25: error: implicit declaration of function
‘cputime_to_nsecs’ [-Werror=implicit-function-declaration]
return local_clock() -
cputime_to_nsecs(kcpustat_this_cpu->cpustat[CPUTIME_STEAL]);
^
I would like to do more than just file a bug report. Further
investigation (cputime.h) shows that cputime_to_nsecs has a
preprocessor guard on the config option (currently enabled)
CONFIG_VIRT_CPU_ACCOUNTING_NATIVE.
CONFIG_PPC_PSERIES is also enabled.
The offending code in arch/powerpc/kernel/time.c is
#ifdef CONFIG_PPC_PSERIES
/*
* Running clock - attempts to give a view of time passing for a virtualised
* kernels.
* Uses the VTB register if available otherwise a next best guess.
*/
unsigned long long running_clock(void)
{
/*
* Don't read the VTB as a host since KVM does not switch in host
* timebase into the VTB when it takes a guest off the CPU, reading the
* VTB would result in reading 'last switched out' guest VTB.
*
* Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it
* would be unsafe to rely only on the #ifdef above.
*/
if (firmware_has_feature(FW_FEATURE_LPAR) &&
cpu_has_feature(CPU_FTR_ARCH_207S))
return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) <<
tb_to_ns_shift;
/*
* This is a next best approximation without a VTB.
* On a host which is running bare metal there should never be any
stolen
* time and on a host which doesn't do any virtualisation TB *should*
equal
* VTB so it makes no difference anyway.
*/
return local_clock() -
cputime_to_nsecs(kcpustat_this_cpu->cpustat[CPUTIME_STEAL]);
}
#endif
Can anyone give me a hint on this one? Where to start reading?
thanks,
Tobin.
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