Re: [PATCH] ARM: at91: fix build for SAMA5D3 w/o L2 cache

From: "Clément Léger" <clement.leger@bootlin.com>
To: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: Claudiu Beznea <claudiu.beznea@microchip.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Russell King <linux@armlinux.org.uk>,
	linux-arm-kernel@lists.infradead.org,
	Peter Rosin <peda@axentia.se>,
	linux-kernel@vger.kernel.org,
	"regressions@lists.linux.dev" <regressions@lists.linux.dev>
Subject: Re: [PATCH] ARM: at91: fix build for SAMA5D3 w/o L2 cache
Date: Tue, 22 Nov 2022 18:14:52 +0100	[thread overview]
Message-ID: <20221122181452.6a386296@fixe.home> (raw)
In-Reply-To: <075d8c0f-5448-73aa-bd3f-0d4e1216e87f@leemhuis.info>

Le Tue, 22 Nov 2022 16:13:40 +0100,
Thorsten Leemhuis <regressions@leemhuis.info> a écrit :

> Hi, this is your Linux kernel regression tracker.
> 
> On 12.11.22 16:40, Peter Rosin wrote:
> > The L2 cache is present on the newer SAMA5D2 and SAMA5D4 families, but
> > apparently not for the older SAMA5D3. At least not always.
> > 
> > Solves a build-time regression with the following symptom:
> > 
> > sama5.c:(.init.text+0x48): undefined reference to `outer_cache'
> > 
> > Fixes: 3b5a7ca7d252 ("ARM: at91: setup outer cache .write_sec() callback if needed")
> > Signed-off-by: Peter Rosin <peda@axentia.se>  
> 
> Clément Léger and Claudiu Beznea: what's up here? Is there a particular
> reason why this patch did get any feedback from you by now? It's ten
> days old and Peter already sent a kind of reminder a few days ago.

Hi Thorsten,

Sorry for the lack of answer, I'm not sure about the best solution to
tackle this problem. adding IS_ENABLED(CONFIG_OUTER_CACHE) seems like a
good way to avoid modifying the whole configuration. If ok for Claudiu,
I think it is the best thing to do since it will work for all cases.

Clément

> 
> Reminder, ideally this regression should be fixed by now. For details
> see the section "Prioritize work on fixing regressions"  in
> Documentation/process/handling-regressions.rst (
> https://docs.kernel.org/process/handling-regressions.html )
> 
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> 
> P.S.: As the Linux kernel's regression tracker I deal with a lot of
> reports and sometimes miss something important when writing mails like
> this. If that's the case here, don't hesitate to tell me in a public
> reply, it's in everyone's interest to set the public record straight.
> 
> > ---
> >  arch/arm/mach-at91/sama5.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > Hi!
> > 
> > I'm not sure this is the correct solution? Maybe SAMA5D3 should bring
> > in CONFIG_OUTER_CACHE unconditionally instead? But that seems like a
> > bigger change, and not just a tweak of the regressing commit...
> > 
> > Cheers,
> > Peter
> > 
> > diff --git a/arch/arm/mach-at91/sama5.c b/arch/arm/mach-at91/sama5.c
> > index 67ed68fbe3a5..bf2b5c6a18c6 100644
> > --- a/arch/arm/mach-at91/sama5.c
> > +++ b/arch/arm/mach-at91/sama5.c
> > @@ -26,7 +26,7 @@ static void sama5_l2c310_write_sec(unsigned long val, unsigned reg)
> >  static void __init sama5_secure_cache_init(void)
> >  {
> >  	sam_secure_init();
> > -	if (sam_linux_is_optee_available())
> > +	if (IS_ENABLED(CONFIG_OUTER_CACHE) && sam_linux_is_optee_available())
> >  		outer_cache.write_sec = sama5_l2c310_write_sec;
> >  }
> >    

-- 
Clément Léger,
Embedded Linux and Kernel engineer at Bootlin
https://bootlin.com