linux-kernel - Re: [PATCH v2 05/25] irqchip/gic-v3: Add FW info retrieval support

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

Message-ID: <86tt121j7o.wl-maz@kernel.org>
Date: Tue, 16 Sep 2025 16:59:55 +0100
From: Marc Zyngier <maz@...nel.org>
To: Jonathan Cameron <jonathan.cameron@...wei.com>
Cc: <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-acpi@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	"Mark\
 Rutland" <mark.rutland@....com>,
	Will Deacon <will@...nel.org>,
	"Rafael J.\
 Wysocki" <rafael@...nel.org>,
	Rob Herring <robh@...nel.org>,
	"Saravana\
 Kannan" <saravanak@...gle.com>,
	Greg Kroah-Hartman
	<gregkh@...uxfoundation.org>,
	Sven Peter <sven@...nel.org>,
	Janne Grunau
	<j@...nau.net>,
	Suzuki K Poulose <suzuki.poulose@....com>,
	James Clark
	<james.clark@...aro.org>
Subject: Re: [PATCH v2 05/25] irqchip/gic-v3: Add FW info retrieval support

On Tue, 16 Sep 2025 16:34:13 +0100,
Jonathan Cameron <jonathan.cameron@...wei.com> wrote:
> 
> On Mon, 15 Sep 2025 09:56:42 +0100
> Marc Zyngier <maz@...nel.org> wrote:
> 
> > Plug the new .get_info() callback into the GICv3 core driver,
> > using some of the existing PPI affinity handling infrastructure.
> > 
> > Signed-off-by: Marc Zyngier <maz@...nel.org>
> Hi Marc,
> 
> Yet another trivial comment. It's one of those days it seems :)

No worries, your trivial comments are far more interesting than some
of the emails I'm otherwise getting.. ;-)

> 
> > ---
> >  drivers/irqchip/irq-gic-v3.c | 53 ++++++++++++++++++++++++++++++++++++
> >  1 file changed, 53 insertions(+)
> > 
> > diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
> > index dbeb85677b08c..71c278ddd1e39 100644
> > --- a/drivers/irqchip/irq-gic-v3.c
> > +++ b/drivers/irqchip/irq-gic-v3.c
> > @@ -69,6 +69,8 @@ struct gic_chip_data {
> >  	bool			has_rss;
> >  	unsigned int		ppi_nr;
> >  	struct partition_desc	**ppi_descs;
> > +	struct partition_affinity *parts;
> > +	unsigned int		nr_parts;
> >  };
> >  
> >  #define T241_CHIPS_MAX		4
> > @@ -1796,11 +1798,58 @@ static int gic_irq_domain_select(struct irq_domain *d,
> >  	return d == partition_get_domain(gic_data.ppi_descs[ppi_idx]);
> >  }
> >  
> > +static int gic_irq_get_fwspec_info(struct irq_fwspec *fwspec, struct irq_fwspec_info *info)
> > +{
> > +	const struct cpumask *mask = NULL;
> > +
> > +	info->flags = 0;
> > +	info->affinity = NULL;
> > +
> > +	/* ACPI is not capable of describing PPI affinity -- yet */
> > +	if (!is_of_node(fwspec->fwnode))
> > +		return 0;
> > +
> > +	/* If the specifier provides an affinity, use it */
> > +	if (fwspec->param_count == 4 && fwspec->param[3]) {
> > +		struct fwnode_handle *fw;
> > +
> > +		switch (fwspec->param[0]) {
> > +		case 1:			/* PPI */
> > +		case 3:			/* EPPI */
> > +			break;
> > +		default:
> > +			return 0;
> > +		}
> > +
> > +		fw = of_node_to_fwnode(of_find_node_by_phandle(fwspec->param[3]));
> 
> of_node_to_fwnode() has a note that says it'll be removed in the merge window.
> It was enough of an oddity I wondered why it existed.

Cargo culted, obviously. And yet another sign that I've been sitting
on these patches for way too long...

> Of course it did say it would be removed in the previous merge window and wasn't...
> Probably want of_fwnode_handle()

Thanks for the hint, I'll add that to v3.

	M.

-- 
Without deviation from the norm, progress is not possible.