Re: [PATCH v2] powerpc/vdso: fix clock_gettime_fallback for vdso32

[Christophe Leroy]

Le 12/01/2021 à 02:13, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@xxxxxxxxxx> writes:
> > From: Andreas Schwab <schwab@xxxxxxxxxxxxxx>
> >
> > The second argument of __kernel_clock_gettime64 points to a struct
> > __kernel_timespec, with 64-bit time_t, so use the clock_gettime64 syscall
> > in the fallback function for the 32-bit vdso.  Similarily,
> > clock_getres_fallback should use the clock_getres_time64 syscall, though
> > it isn't yet called from the 32-bit vdso.
> >
> > Signed-off-by: Andreas Schwab <schwab@xxxxxxxxxxxxxx>
> > [chleroy: Moved into the #ifdef CONFIG_VDSO32 block]
>
> That doesn't build for 64-bit with compat VDSO. Should I just take
> Andreas' version, or do you want to send a v3?

Yes, that #ifdef CONFIG_VDSO32 is crazy, should use __powerpc64__ instead, or __VDSO32__ but that 
one is defined in asflags-y so not sure we have it in C.

I sent v3 just before lunch.

Christophe

> cheers
>
> > Fixes: d0e3fc69d00d ("powerpc/vdso: Provide __kernel_clock_gettime64() on vdso32")
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> > ---
> >   arch/powerpc/include/asm/vdso/gettimeofday.h | 27 +++++++++++++++-----
> >   1 file changed, 21 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/powerpc/include/asm/vdso/gettimeofday.h b/arch/powerpc/include/asm/vdso/gettimeofday.h
> > index 7a215cc5da77..3ecddd9c6302 100644
> > --- a/arch/powerpc/include/asm/vdso/gettimeofday.h
> > +++ b/arch/powerpc/include/asm/vdso/gettimeofday.h
> > @@ -102,22 +102,22 @@ int gettimeofday_fallback(struct __kernel_old_timeval *_tv, struct timezone *_tz
> >   	return do_syscall_2(__NR_gettimeofday, (unsigned long)_tv, (unsigned long)_tz);
> >   }
> >   
> > +#ifdef CONFIG_VDSO32
> > +
> > +#define BUILD_VDSO32		1
> > +
> >   static __always_inline
> >   int clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
> >   {
> > -	return do_syscall_2(__NR_clock_gettime, _clkid, (unsigned long)_ts);
> > +	return do_syscall_2(__NR_clock_gettime64, _clkid, (unsigned long)_ts);
> >   }
> >   
> >   static __always_inline
> >   int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
> >   {
> > -	return do_syscall_2(__NR_clock_getres, _clkid, (unsigned long)_ts);
> > +	return do_syscall_2(__NR_clock_getres_time64, _clkid, (unsigned long)_ts);
> >   }
> >   
> > -#ifdef CONFIG_VDSO32
> > -
> > -#define BUILD_VDSO32		1
> > -
> >   static __always_inline
> >   int clock_gettime32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
> >   {
> > @@ -129,6 +129,21 @@ int clock_getres32_fallback(clockid_t _clkid, struct old_timespec32 *_ts)
> >   {
> >   	return do_syscall_2(__NR_clock_getres, _clkid, (unsigned long)_ts);
> >   }
> > +
> > +#else
> > +
> > +static __always_inline
> > +int clock_gettime_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
> > +{
> > +	return do_syscall_2(__NR_clock_gettime, _clkid, (unsigned long)_ts);
> > +}
> > +
> > +static __always_inline
> > +int clock_getres_fallback(clockid_t _clkid, struct __kernel_timespec *_ts)
> > +{
> > +	return do_syscall_2(__NR_clock_getres, _clkid, (unsigned long)_ts);
> > +}
> > +
> >   #endif
> >   
> >   static __always_inline u64 __arch_get_hw_counter(s32 clock_mode,
> > --
> > 2.25.0