On Tue, Feb 21, 2017 at 09:53:01PM +1100, Tobin C. Harding wrote:
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.
Mistake made, CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is *not* enabled. $ cat .config | grep CONFIG_VIRT_CPU # CONFIG_VIRT_CPU_ACCOUNTING_NATIVE is not set # CONFIG_VIRT_CPU_ACCOUNTING_GEN is not set $ cat .config | grep CONFIG_PPC_PSERIES CONFIG_PPC_PSERIES=y
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?
Removing the compile time guard allows the build to proceed, surely this is not the correct solution though. diff --git a/arch/powerpc/include/asm/cputime.h b/arch/powerpc/include/asm/cputime.h index 99b5418..15482cb 100644 --- a/arch/powerpc/include/asm/cputime.h +++ b/arch/powerpc/include/asm/cputime.h @@ -16,7 +16,7 @@ #ifndef __POWERPC_CPUTIME_H #define __POWERPC_CPUTIME_H -#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE + #include <linux/types.h> #include <linux/time.h> @@ -53,5 +53,5 @@ void arch_vtime_task_switch(struct task_struct *tsk); #endif #endif /* __KERNEL__ */ -#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ + #endif /* __POWERPC_CPUTIME_H */ diff --git a/include/linux/cputime.h b/include/linux/cputime.h index a691dc4..f730c14 100644 --- a/include/linux/cputime.h +++ b/include/linux/cputime.h @@ -1,13 +1,13 @@ #ifndef __LINUX_CPUTIME_H #define __LINUX_CPUTIME_H -#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE + #include <asm/cputime.h> #ifndef cputime_to_nsecs -# define cputime_to_nsecs(__ct) \ +#define cputime_to_nsecs(__ct) \ (cputime_to_usecs(__ct) * NSEC_PER_USEC) #endif -#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ + #endif /* __LINUX_CPUTIME_H */ thanks, Tobin.