Re: [PATCH] powerpc: sstep: Mark variable `rc` as unused in function 'analyse_instr'

[Christophe Leroy]

Le 12/03/2019 Ã 22:12, Mathieu Malaterre a ÃcritÂ:
> On Tue, Mar 12, 2019 at 9:56 PM Christophe Leroy
> <christophe.leroy@xxxxxx> wrote:
> > Le 12/03/2019 Ã 21:20, Mathieu Malaterre a Ãcrit :
> > > Add gcc attribute unused for `rc` variable.
> > >
> > > Fix warnings treated as errors with W=1:
> > >
> > >     arch/powerpc/lib/sstep.c:1172:31: error: variable 'rc' set but not used [-Werror=unused-but-set-variable]
> > >
> > > Signed-off-by: Mathieu Malaterre <malat@xxxxxxxxxx>
> > > ---
> > >    arch/powerpc/lib/sstep.c | 2 +-
> > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
> > > index 3d33fb509ef4..32d092f62ae0 100644
> > > --- a/arch/powerpc/lib/sstep.c
> > > +++ b/arch/powerpc/lib/sstep.c
> > > @@ -1169,7 +1169,7 @@ static nokprobe_inline int trap_compare(long v1, long v2)
> > >    int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
> > >                  unsigned int instr)
> > >    {
> > > -     unsigned int opcode, ra, rb, rc, rd, spr, u;
> > > +     unsigned int opcode, ra, rb, rc __maybe_unused, rd, spr, u;
> >
> > I think it would be better to enclose 'rc' inside a #ifdef CONFIG_PPC64
>
> Hum odd, I would have bet you would have suggested me to use
> IS_ENABLED with some crazy scheme (I was not able to mix it with the
> switch case nicely).

Well I guess yes, you could also get rid of the #ifdef __powerpc64__ and 
instead add the following just after the 'case 4:'

if (!IS_ENABLED(CONFIG_64))
	break;

That's less uggly than adding two #ifdef/#endif

Christophe

> Anyway I'll try your suggestion and post a v2.
>
> > Christophe
> >
> > >        unsigned long int imm;
> > >        unsigned long int val, val2;
> > >        unsigned int mb, me, sh;