From mboxrd@z Thu Jan  1 00:00:00 1970
From: Phil Edworthy <phil.edworthy@renesas.com>
Date: Wed, 18 Nov 2015 18:01:39 +0000
Subject: RE: [PATCH] PCI: pcie-rcar: Fix OF node passed to MSI irq domain
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To: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thierry Reding <treding@nvidia.com>, Bjorn Helgaas <bhelgaas@google.com>, Wolfram Sang <wsa@the-dreams.de>, Geert Uytterhoeven <geert@linux-m68k.org>, Simon Horman <horms@verge.net.au>, "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>, "linux-sh@vger.kernel.org" <linux-sh@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Ley Foon Tan <lftan@altera.com>, Jingoo Han <jg1.han@samsung.com>

Hi Marc,

On 16 November 2015 18:31, Marc Zyngier wrote:
> On 13/11/15 09:36, Phil Edworthy wrote:
<snip>
> > Since the stack trace doesn't help that much I added some tracing:
> > pci_msi_setup_msi_irqs()
> >   calls pci_msi_get_domain()
> >     calls dev_get_msi_domain(), gets a non-NULL domain.
> > pci_msi_setup_msi_irqs()
> >   calls pci_msi_domain_alloc_irqs()
> >     calls msi_domain_alloc_irqs()
> > msi_domain_alloc_irqs:273: ops=FFffffc03193a810
> > msi_domain_alloc_irqs:274: ops->msi_check=FFffffc031161418
> > systemd-udevd[1311]: undefined instruction: pc=FFffffc03116141c
> > That looks to me as though msi_check is off pointing to the weeds.
>=20
> So the next step is to find out who initializes msi_check. Assuming
> someone does...
Nothing initializes msi_check...=20

=20
> > By passing a NULL domain into irq_domain_add_linear() you get:
> > pci_msi_setup_msi_irqs()
> >   calls pci_msi_get_domain()
> >     calls dev_get_msi_domain(), gets a NULL domain.
> >     calls arch_setup_msi_irq()
> > All ok then.
>=20
> Yes, because you're sidestepping the issue. Any chance you could dig a
> bit deeper? I'd really like to nail this one down (before we convert
> your PCI driver to the right API... ;-).
The problem appears to be that when the pci host driver enables msi
it calls the following:
	msi->domain =3D irq_domain_add_linear(pcie->dev->of_node, INT_PCI_MSI_NR,
					    &msi_domain_ops, &msi->chip);
The last arg is documented as:
* @host_data: Controller private data pointer=20
In _irq_domain_add() this ptr is stored in struct irq_domain's host_data.

However, msi_domain_alloc_irqs() expects host_data to be a ptr to a
struct msi_domain_info.

It seems that a number of other pci host drivers do the same, so I am
surprised that no one else has seen this.

Thanks for your help,
Phil


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From: Phil Edworthy <phil.edworthy@renesas.com>
To: Marc Zyngier <marc.zyngier@arm.com>
CC: Thierry Reding <treding@nvidia.com>, Bjorn Helgaas <bhelgaas@google.com>,
        Wolfram Sang <wsa@the-dreams.de>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Simon Horman <horms@verge.net.au>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-sh@vger.kernel.org" <linux-sh@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Ley Foon Tan <lftan@altera.com>, Jingoo Han <jg1.han@samsung.com>
Subject: RE: [PATCH] PCI: pcie-rcar: Fix OF node passed to MSI irq domain
Thread-Topic: [PATCH] PCI: pcie-rcar: Fix OF node passed to MSI irq domain
Thread-Index: AQHRFhpazS7O4def1E+1x+YbvdM7WJ6T04kggAASxwCAABC7IIAADPxggAFvZICAAZ8KAIABBYmAgADN4gCAANc20IAFULmAgAMTyRA=
Date: Wed, 18 Nov 2015 18:01:39 +0000
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Hi Marc,

On 16 November 2015 18:31, Marc Zyngier wrote:
> On 13/11/15 09:36, Phil Edworthy wrote:
<snip>
> > Since the stack trace doesn't help that much I added some tracing:
> > pci_msi_setup_msi_irqs()
> >   calls pci_msi_get_domain()
> >     calls dev_get_msi_domain(), gets a non-NULL domain.
> > pci_msi_setup_msi_irqs()
> >   calls pci_msi_domain_alloc_irqs()
> >     calls msi_domain_alloc_irqs()
> > msi_domain_alloc_irqs:273: ops=ffffffc03193a810
> > msi_domain_alloc_irqs:274: ops->msi_check=ffffffc031161418
> > systemd-udevd[1311]: undefined instruction: pc=ffffffc03116141c
> > That looks to me as though msi_check is off pointing to the weeds.
> 
> So the next step is to find out who initializes msi_check. Assuming
> someone does...
Nothing initializes msi_check... 

 
> > By passing a NULL domain into irq_domain_add_linear() you get:
> > pci_msi_setup_msi_irqs()
> >   calls pci_msi_get_domain()
> >     calls dev_get_msi_domain(), gets a NULL domain.
> >     calls arch_setup_msi_irq()
> > All ok then.
> 
> Yes, because you're sidestepping the issue. Any chance you could dig a
> bit deeper? I'd really like to nail this one down (before we convert
> your PCI driver to the right API... ;-).
The problem appears to be that when the pci host driver enables msi
it calls the following:
	msi->domain = irq_domain_add_linear(pcie->dev->of_node, INT_PCI_MSI_NR,
					    &msi_domain_ops, &msi->chip);
The last arg is documented as:
* @host_data: Controller private data pointer 
In _irq_domain_add() this ptr is stored in struct irq_domain's host_data.

However, msi_domain_alloc_irqs() expects host_data to be a ptr to a
struct msi_domain_info.

It seems that a number of other pci host drivers do the same, so I am
surprised that no one else has seen this.

Thanks for your help,
Phil