Re: [PATCH v2 -next] powerpc: kernel/time.c - cleanup warnings

[Christophe Leroy]

Le 24/03/2021 à 00:05, Alexandre Belloni a écrit :
> On 23/03/2021 23:18:17+0100, Alexandre Belloni wrote:
> > Hello,
> >
> > On 23/03/2021 05:12:57-0400, He Ying wrote:
> > > We found these warnings in arch/powerpc/kernel/time.c as follows:
> > > warning: symbol 'decrementer_max' was not declared. Should it be static?
> > > warning: symbol 'rtc_lock' was not declared. Should it be static?
> > > warning: symbol 'dtl_consumer' was not declared. Should it be static?
> > >
> > > Declare 'decrementer_max' and 'rtc_lock' in powerpc asm/time.h.
> > > Rename 'rtc_lock' in drviers/rtc/rtc-vr41xx.c to 'vr41xx_rtc_lock' to
> > > avoid the conflict with the variable in powerpc asm/time.h.
> > > Move 'dtl_consumer' definition behind "include <asm/dtl.h>" because it
> > > is declared there.
> > >
> > > Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> > > Signed-off-by: He Ying <heying24@xxxxxxxxxx>
> > > ---
> > > v2:
> > > - Instead of including linux/mc146818rtc.h in powerpc kernel/time.c, declare
> > >    rtc_lock in powerpc asm/time.h.
> >
> > V1 was actually the correct thing to do. rtc_lock is there exactly
> > because chrp and maple are using mc146818 compatible RTCs. This is then
> > useful because then drivers/char/nvram.c is enabled. The proper fix
> > would be to scrap all of that and use rtc-cmos for those platforms as
> > this drives the RTC properly and exposes the NVRAM for the mc146818.
> >
> > Or at least, if there are no users for the char/nvram driver on those
> > two platforms, remove the spinlock and stop enabling CONFIG_NVRAM or
> > more likely rename the symbol as it seems to be abused by both chrp and
> > powermac.
>
> Ok so rtc_lock is not even used by the char/nvram.c driver as it is
> completely compiled out.
>
> I guess it is fine having it move to the individual platform as looking
> very quickly at the Kconfig, it is not possible to select both
> simultaneously. Tentative patch:

Looking at it once more, it looks like including linux/mc146818rtc.h is the thing to do, at least 
for now. Several platforms are defining the rtc_lock exactly the same way as powerpc does, and 
including mc146818rtc.h

I think that to get it clean, this change should go in a dedicated patch and do a bit more and 
explain exactly what is being do and why. I'll try to draft something for it.

He Y., can you make a version v3 of your patch excluding the rtc_lock change ?

Christophe