Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   "Yang, Shunyong" <shunyong.yang@hxt-semitech.com>
To:     "tglx@linutronix.de" <tglx@linutronix.de>,
        "marc.zyngier@arm.com" <marc.zyngier@arm.com>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Zheng, Joey" <yu.zheng@hxt-semitech.com>
Subject: Re: [PATCH] irqdomain: provide useful debugging information for irq
 domain
Thread-Topic: [PATCH] irqdomain: provide useful debugging information for
 irq domain
Thread-Index: AQHTj4AHsJhr+18M4E+PKWkEOXafu6N4WSMAgAB1jICAADWaAA==
Date:   Thu, 18 Jan 2018 12:06:06 +0000
Message-ID: <1516277158.15644.43.camel@hxt-semitech.com>
References: <1516163877-32396-1-git-send-email-shunyong.yang@hxt-semitech.com>
         <210f90d0-1588-2185-4845-d5d143183621@arm.com>
         <alpine.DEB.2.20.1801171018000.1777@nanos>
         <1516181177.3280.13.camel@hxt-semitech.com>
         <alpine.DEB.2.20.1801171032490.1777@nanos>
         <1516182426.3280.19.camel@hxt-semitech.com>
         <alpine.DEB.2.20.1801171056330.1777@nanos>
         <1516184428.3280.25.camel@hxt-semitech.com>
         <d3526488-6706-22d4-1d50-6c595f6f5d3f@arm.com>
         <1516240404.15644.23.camel@hxt-semitech.com>
         <f12b7b93-cf0e-d246-224a-2eb791a9d718@arm.com>
In-Reply-To: <f12b7b93-cf0e-d246-224a-2eb791a9d718@arm.com>
Accept-Language: en-US
Content-Language: en-US
Content-Type: text/plain; charset="iso-8859-15"
Content-ID: <4089A9CBD552234E895B1FCEDE33E8A5@hxt-semitech.com>
Content-Transfer-Encoding: 8BIT
MIME-Version: 1.0
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi, Marc

On Thu, 2018-01-18 at 08:54 +0000, Marc Zyngier wrote:
> On 18/01/18 01:53, Yang, Shunyong wrote:
> > 
> > Hi, Marc
> > 
> > On Wed, 2018-01-17 at 10:43 +0000, Marc Zyngier wrote:
> > > 
> > > On 17/01/18 10:20, Yang, Shunyong wrote:
> > > > 
> > > > 
> > > > Hi, Thomas and Marc,
> > > > 
> > > > On Wed, 2018-01-17 at 11:01 +0100, Thomas Gleixner wrote:
> > > > > 
> > > > > 
> > > > > On Wed, 17 Jan 2018, Yang, Shunyong wrote:
> > > > > > 
> > > > > > 
> > > > > > 
> > > > > > On Wed, 2018-01-17 at 10:33 +0100, Thomas Gleixner wrote:
> > > > > > > 
> > > > > > > 
> > > > > > > 
> > > > > > > And how is that different from:
> > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > 
> > > > > > > > The nodes under debugfs irq/irqs describes information
> > > > > > > > of
> > > > > > > > every
> > > > > > > > single
> > > > > > > > irq.
> > > > > > > Not at all. It contains the complete hierarchical
> > > > > > > information
> > > > > > > of
> > > > > > > each
> > > > > > > virq.
> > > > > > > 
> > > > > > I think irq_domain_mapping can provide some high-level
> > > > > > information
> > > > > > in a
> > > > > > summary style.
> > > > > > For example, we can check all the IRQs connect to a
> > > > > > specific
> > > > > > irq
> > > > > > chip
> > > > > > or irq domain.
> > > > > You can retrieve the same information from the irq/irqs
> > > > > files.
> > > > > All it
> > > > > takes
> > > > > is a shell script.
> > > > > 
> > > > > Aside of that with hierarchical irq domains the old debug
> > > > > output
> > > > > is
> > > > > just
> > > > > useless.
> > > > > 
> > > > Umm...Agree. Need I post a patch to remove it?
> > > I'm on it.
> > > 
> > In addition to the "%p" to "%px" change in?IRQ_DOMAIN_DEBUG you
> > have
> > posted patch to remove it, my original patch includes several other
> > changes:
> > 1. change to "%px" in kasprintf() parameters in
> > function?__irq_domain_alloc_fwnode() to build name which reflects
> > the
> > real pointer address from caller, this may be useful when reading
> > debug
> > information.
> > ?
> > n = kasprintf(GFP_KERNEL, "irqchip@%px", data);
> Have you investigated whether %pK would work in a debug context?

Although build name with physical address makes it straightforward when
working with tables like MADT. I agree with you about the security
concern. As it's just a name, hashed address is OK.

But it brings new issues. Currently, component like GIC calls this
function with virtual address and ITS with physical address. Is there
possibility that GIC/ITS name is different in each boot? Should we
change GIC/ITS fw handle allocate to name/name-id style?

Thanks
Shunyong?