On Mon, 2019-08-26 at 21:41 +1000, Michael Ellerman wrote: > Christophe Leroy <christophe.le...@c-s.fr> writes: > > sched_clock(), used by printk(), calls __USE_RTC() to know > > whether to use realtime clock or timebase. > > > > __USE_RTC() uses cpu_has_feature() which is initialised by > > machine_init(). Before machine_init(), __USE_RTC() returns true, > > leading to a program check exception on CPUs not having realtime > > clock. > > > > In order to be able to use printk() earlier, use feature fixup. > > Feature fixups are applies in early_init(), enabling the use of > > printk() earlier. > > > > Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr> > > --- > > arch/powerpc/include/asm/time.h | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > The other option would be just to make this a compile time decision, eg. > add CONFIG_PPC_601 and use that to gate whether we use RTC. > > Given how many 601 users there are, maybe 1?, I think that would be a > simpler option and avoids complicating the code / binary for everyone > else.
Didn't we ditch 601 support years ago anyway ? We had workaround we threw out I think... Cheers, Ben. > cheers > > > diff --git a/arch/powerpc/include/asm/time.h > > b/arch/powerpc/include/asm/time.h > > index 54f4ec1f9fab..3455cb54c333 100644 > > --- a/arch/powerpc/include/asm/time.h > > +++ b/arch/powerpc/include/asm/time.h > > @@ -42,7 +42,14 @@ struct div_result { > > /* Accessor functions for the timebase (RTC on 601) registers. */ > > /* If one day CONFIG_POWER is added just define __USE_RTC as 1 */ > > #ifdef CONFIG_PPC_BOOK3S_32 > > -#define __USE_RTC() (cpu_has_feature(CPU_FTR_USE_RTC)) > > +static inline bool __USE_RTC(void) > > +{ > > + asm_volatile_goto(ASM_FTR_IFCLR("nop;", "b %1;", %0) :: > > + "i" (CPU_FTR_USE_RTC) :: l_use_rtc); > > + return false; > > +l_use_rtc: > > + return true; > > +} > > #else > > #define __USE_RTC() 0 > > #endif > > -- > > 2.13.3