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Date: Fri, 21 Jul 2017 13:05:03 +1000
From: Anton Blanchard <anton@ozlabs.org>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Santosh Sivaraj <santosh@fossix.org>, linuxppc-dev
 <linuxppc-dev@lists.ozlabs.org>, Srikar Dronamraju
 <srikar@linux.vnet.ibm.com>
Subject: Re: [PATCH] powerpc/vdso64: Add support for
 CLOCK_{REALTIME/MONOTONIC}_COARSE
Message-ID: <20170721130503.6e28a1e0@kryten>
In-Reply-To: <87bmofgsbh.fsf@concordia.ellerman.id.au>
References: <20170720095834.15153-1-santosh@fossix.org>
 <87bmofgsbh.fsf@concordia.ellerman.id.au>
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Hi,

> > +static notrace int gettime_syscall_fallback(clockid_t clk_id,
> > +					     struct timespec *tp)
> > +{
> > +	register clockid_t id asm("r3") = clk_id;
> > +	register struct timespec *t asm("r4") = tp;
> > +	register int nr asm("r0") = __NR_clock_gettime;
> > +	register int ret asm("r3");  
> 
> I guess this works. I've always been a bit nervous about register
> variables TBH.

I don't think this works with clang unfortunately.

Anton