Re: [PATCH v2 1/5] arm64: Fix vDSO clock_getres()

[Will Deacon <will.deacon@arm.com>]

On Tue, Apr 16, 2019 at 05:24:33PM +0100, Catalin Marinas wrote:
> On Tue, Apr 16, 2019 at 05:14:30PM +0100, Vincenzo Frascino wrote:
> > diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
> > index 2d419006ad43..5f5759d51c33 100644
> > --- a/arch/arm64/kernel/vdso.c
> > +++ b/arch/arm64/kernel/vdso.c
> > @@ -245,6 +245,8 @@ void update_vsyscall(struct timekeeper *tk)
> >  		vdso_data->cs_shift		= tk->tkr_mono.shift;
> >  	}
> >  
> > +	vdso_data->hrtimer_res		= hrtimer_resolution;
> 
> This should be a WRITE_ONCE(), just in case.
> 
> > +
> >  	smp_wmb();
> >  	++vdso_data->tb_seq_count;
> >  }
> > diff --git a/arch/arm64/kernel/vdso/gettimeofday.S b/arch/arm64/kernel/vdso/gettimeofday.S
> > index c39872a7b03c..e2e9dfe9ba4a 100644
> > --- a/arch/arm64/kernel/vdso/gettimeofday.S
> > +++ b/arch/arm64/kernel/vdso/gettimeofday.S
> > @@ -296,32 +296,32 @@ ENDPROC(__kernel_clock_gettime)
> >  /* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res); */
> >  ENTRY(__kernel_clock_getres)
> >  	.cfi_startproc
> > +	adr	vdso_data, _vdso_data
> >  	cmp	w0, #CLOCK_REALTIME
> >  	ccmp	w0, #CLOCK_MONOTONIC, #0x4, ne
> >  	ccmp	w0, #CLOCK_MONOTONIC_RAW, #0x4, ne
> > -	b.ne	1f
> > +	b.ne	2f
> >  
> > -	ldr	x2, 5f
> > -	b	2f
> > -1:
> > +1:	/* Get hrtimer_res */
> > +	ldr	x2, [vdso_data, #CLOCK_REALTIME_RES]
> 
> And here we need an "ldr w2, ..." since hrtimer_res is u32.
> 
> With the above (which Will can fix up):
> 
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

Applied, with the above and a few extra cleanups.

Will