RE: [PATCH] perf/arm-cmn: fix compilation issue

[Liming Wu]

> The kernel builds as gnu11 (i.e. C11 + GNU extensions) since commit:
> 
>   e8c07082a810fbb9 ("Kbuild: move to -std=gnu11")
> 
> ... so that warning shouldn't be happenning.
> 
> How are you triggering this? Have you modified KBUILD_CFLAGS?

Thanks for reply.
This error occurs for I compiled the arn-cmn module separately.

> -----Original Message-----
> From: Mark Rutland <mark.rutland@xxxxxxx>
> Sent: Monday, May 15, 2023 4:31 PM
> To: Liming Wu <liming.wu@xxxxxxxxxxxxxxx>
> Cc: will@xxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; robin.murphy@xxxxxxx
> Subject: Re: [PATCH] perf/arm-cmn: fix compilation issue
> 
> On Mon, May 15, 2023 at 09:29:30AM +0800, liming.wu@xxxxxxxxxxxxxxx
> wrote:
> > From: Liming Wu <liming.wu@xxxxxxxxxxxxxxx>
> >
> > This patch is used to fix following compilation issue with legacy gcc
> > and define variables at the beginning of the function
> >
> > error: ‘for’ loop initial declarations are only allowed in C99 or C11 mode
> > 2098 |                 for (int p = 0; p < CMN_MAX_PORTS; p++)
> 
> The kernel builds as gnu11 (i.e. C11 + GNU extensions) since commit:
> 
>   e8c07082a810fbb9 ("Kbuild: move to -std=gnu11")
> 
> ... so that warning shouldn't be happenning.
> 
> How are you triggering this? Have you modified KBUILD_CFLAGS?
> 
> > Signed-off-by: Liming Wu <liming.wu@xxxxxxxxxxxxxxx>
> > ---
> >  drivers/perf/arm-cmn.c | 13 ++++++++-----
> >  1 file changed, 8 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index
> > 47d359f72957..2299fcde5b4a 100644
> > --- a/drivers/perf/arm-cmn.c
> > +++ b/drivers/perf/arm-cmn.c
> > @@ -2009,8 +2009,11 @@ static int arm_cmn_discover(struct arm_cmn *cmn,
> unsigned int rgn_offset)
> >  	u16 child_count, child_poff;
> >  	u32 xp_offset[CMN_MAX_XPS];
> >  	u64 reg;
> > -	int i, j;
> > +	int i, j, p;
> >  	size_t sz;
> > +	void __iomem *xp_region;
> > +	struct arm_cmn_node *xp;
> > +	unsigned int xp_ports;
> >
> >  	arm_cmn_init_node_info(cmn, rgn_offset, &cfg);
> >  	if (cfg.type != CMN_TYPE_CFG)
> > @@ -2067,9 +2070,9 @@ static int arm_cmn_discover(struct arm_cmn *cmn,
> unsigned int rgn_offset)
> >  	cmn->dns = dn;
> >  	cmn->dtms = dtm;
> >  	for (i = 0; i < cmn->num_xps; i++) {
> > -		void __iomem *xp_region = cmn->base + xp_offset[i];
> > -		struct arm_cmn_node *xp = dn++;
> > -		unsigned int xp_ports = 0;
> > +		xp_region = cmn->base + xp_offset[i];
> > +		xp = dn++;
> > +		xp_ports = 0;
> 
> None of these are for loop initial declarations. Even if we wanted to avoid the
> warning, there's no need for these to change.
> 
> >
> >  		arm_cmn_init_node_info(cmn, xp_offset[i], xp);
> >  		/*
> > @@ -2095,7 +2098,7 @@ static int arm_cmn_discover(struct arm_cmn *cmn,
> unsigned int rgn_offset)
> >  		 * from this, since in that case we will see at least one XP
> >  		 * with port 2 connected, for the HN-D.
> >  		 */
> > -		for (int p = 0; p < CMN_MAX_PORTS; p++)
> > +		for (p = 0; p < CMN_MAX_PORTS; p++)
> 
> This shouldn't be necessary given the jernel builds as gnu11.
> 
> Thanks,
> Mark.
> 
> >  			if (arm_cmn_device_connect_info(cmn, xp, p))
> >  				xp_ports |= BIT(p);
> >
> > --
> > 2.25.1
> >