linux-kernel - Re: [PATCH] irqchip: gic: ignore empty processor target registers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <54CC220C.2030202@codeaurora.org>
Date:	Fri, 30 Jan 2015 16:30:04 -0800
From:	Stephen Boyd <sboyd@...eaurora.org>
To:	Stefan Agner <stefan@...er.ch>, tglx@...utronix.de,
	jason@...edaemon.net
CC:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] irqchip: gic: ignore empty processor target registers

On 01/30/15 16:26, Stefan Agner wrote:
> On initialization time, the GIC driver reads the processor target
> register (ICDIPTR) to determine the CPU's mask. On uniprocessor
> systems with GIC controller (e.g. Cortex-A5 SoC's) this register
> is RAZ/WI and hence the mask ends up being zero. This leads to the
> somewhat confusing boot message:
> [    0.000000] GIC CPU mask not found - kernel will fail to boot.
>
> To avoid the message, print the error only on SMP systems.
>
> Signed-off-by: Stefan Agner <stefan@...er.ch>
> ---
> I would like to get rid of this critical message in my bootlog, it
> sounds somewhat... intimidating...

Agreed. I sent a patch to do this a while ago but it never went anywhere
because of maintainership confusions.

http://marc.info/?l=linux-arm-kernel&m=137723356232002&w=2

>
> Actually the driver could also conditionally avoid setting up
> GIC_DIST_TARGET, since it's RAZ/WI (write ignored) on uniprocessor
> systems. But I'm not sure if is_smp() is really reflecting all
> SoC's using GIC which need the Interrupt Processor Targets register
> configured.
>
>  drivers/irqchip/irq-gic.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index d617ee5..7d4f0f5 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -346,7 +346,7 @@ static u8 gic_get_cpumask(struct gic_chip_data *gic)
>  			break;
>  	}
>  
> -	if (!mask)
> +	if (!mask && is_smp())
>  		pr_crit("GIC CPU mask not found - kernel will fail to boot.\n");
>  
>  	return mask;


-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/