Re: [PATCH] pci: fix unavailable irq number 255 reported by BIOS

[Cao jin <caoj.fnst@cn.fujitsu.com>]

Hi,

     IMHO, I think maybe modification on i801_smbus driver is easier.

     Because when i801_smbus request_irq using pci_dev->irq, this 
pci_dev->irq seems still holds the value read from register( 
pci_setup_device->pci_read_irq), if the value is 255, it is invalid in 
register, but when request_irq, 255 is a valid value(with 
CONFIG_X86_IO_APIC & CONFIG_PCI_MSI defined). so I guess maybe we can do 
a judgement in i801_smbus, like:

     if (pci_dev->irq == 255) {

         conversion to another irq # which maybe still not be used
     }


On 01/20/2016 08:24 AM, Bjorn Helgaas wrote:
> [+cc Jiang]
>
> Hi Chen,
>
> On Tue, Jan 19, 2016 at 02:43:30PM +0100, Rafael J. Wysocki wrote:
>> On Tuesday, January 19, 2016 09:45:13 AM Chen Fan wrote:
>>> In our environment, when enable Secure boot, we found an abnormal
>
> This has more information than necessary.  I don't think Secure Boot is
> really relevant, and nor are the timestamps and stack addresses below.
>
>>> phenomenon as following call trace shows. after investigation, we
>>> found the firmware assigned an irq number 255 which means unknown
>>> or no connection in PCI local spec for i801_smbus, meanwhile the
>>> ACPI didn't configure the pci irq routing. and the 255 irq number
>>> was assigned for megasa msix without IRQF_SHARED. then in this case
>>> during i801_smbus probe, the i801_smbus driver would request irq with
>>> bad irq number 255. but the 255 irq number was assigned for memgasa
>>> with MSIX enable. which will cause request_irq fails, and call trace
>>> shows, actually, we should expose the error early, rather than in request
>>> irq, here we simply fix the problem by return err when find the irq is
>>> 255.
>
>>> See the call trace:
>>>
>>>   [   32.459195] ipmi device interface
>>>   [   32.612907] shpchp: Standard Hot Plug PCI Controller Driver version: 0.4
>>>   [   32.800459] ixgbe: Intel(R) 10 Gigabit PCI Express Network Driver - version 4.0.1-k-rh
>>>   [   32.818319] ixgbe: Copyright (c) 1999-2014 Intel Corporation.
>>>   [   32.844009] lpc_ich 0001:80:1f.0: I/O space for ACPI uninitialized
>>>   [   32.850093] i801_smbus 0000:00:1f.3: enabling device (0140 -> 0143)
>>>   [   32.851134] i801_smbus 0000:00:1f.3: can't derive routing for PCI INT C
>>>   [   32.851136] i801_smbus 0000:00:1f.3: PCI INT C: no GSI
>>>   [   32.851164] genirq: Flags mismatch irq 255. 00000080 (i801_smbus) vs. 00000000 (megasa
>>>   [   32.851168] CPU: 0 PID: 2487 Comm: kworker/0:1 Not tainted 3.10.0-229.el7.x86_64 #1
>>>   [   32.851170] Hardware name: FUJITSU PRIMEQUEST 2800E2/D3736, BIOS PRIMEQUEST 2000 Serie5
>>>   [   32.851178] Workqueue: events work_for_cpu_fn
>>>   [   32.851208]  ffff88086c330b00 00000000e233a9df ffff88086d57bca0 ffffffff81603f36
>>>   [   32.851227]  ffff88086d57bcf8 ffffffff8110d23a ffff88686fe02000 0000000000000246
>>>   [   32.851246]  ffff88086a9a8c00 00000000e233a9df ffffffffa00ad220 0000000000000080
>>>   [   32.851247] Call Trace:
>>>   [   32.851261]  [<ffffffff81603f36>] dump_stack+0x19/0x1b
>>>   [   32.851271]  [<ffffffff8110d23a>] __setup_irq+0x54a/0x570
>>>   [   32.851282]  [<ffffffffa00ad220>] ? i801_check_pre.isra.5+0xe0/0xe0 [i2c_i801]
>>>   [   32.851289]  [<ffffffff8110d3bc>] request_threaded_irq+0xcc/0x170
>>>   [   32.851298]  [<ffffffffa00ae87f>] i801_probe+0x32f/0x508 [i2c_i801]
>>>   [   32.851308]  [<ffffffff81308385>] local_pci_probe+0x45/0xa0
>>>   [   32.851315]  [<ffffffff8108bfd4>] work_for_cpu_fn+0x14/0x20
>>>   [   32.851323]  [<ffffffff8108f0ab>] process_one_work+0x17b/0x470
>>>   [   32.851330]  [<ffffffff81090003>] worker_thread+0x293/0x400
>>>   [   32.851338]  [<ffffffff8108fd70>] ? rescuer_thread+0x400/0x400
>>>   [   32.851346]  [<ffffffff8109726f>] kthread+0xcf/0xe0
>>>   [   32.851353]  [<ffffffff810971a0>] ? kthread_create_on_node+0x140/0x140
>>>   [   32.851362]  [<ffffffff81613cfc>] ret_from_fork+0x7c/0xb0
>>>   [   32.851369]  [<ffffffff810971a0>] ? kthread_create_on_node+0x140/0x140
>>>   [   32.851373] i801_smbus 0000:00:1f.3: Failed to allocate irq 255: -16
>>>   [   32.851435] i801_smbus: probe of 0000:00:1f.3 failed with error -16
>
> Since the Interrupt Line register is writable and might contain any
> value, it would be nice if Linux could at least tolerate anything
> firmware might leave there without a backtrace, even if we end up not
> being able to use the device.
>
> Your patch changes the acpi_pci_irq_enable() return value from 0 to
> -EINVAL for this case.  You're running v3.10, and this change probably
> makes pci_enable_device() fail.  I suppose the user-visible effect is
> that with your patch,
>
>    - there's no backtrace,
>    - i801_smbus fails with "Failed to enable SMBus PCI device" instead
>      of with "Failed to allocate irq 255", and
>    - i801_smbus fails even if no other device is using IRQ 255, instead
>      of "succeeding" and using an IRQ 255 that probably doesn't work
>      (this seems like maybe the most important difference)
>
> Jiang has changed this path with 890e4847587f ("PCI: Add
> pcibios_alloc_irq() and pcibios_free_irq()"), so I think on newer
> kernels, we'll never even call the i801_smbus probe function.
>
> What behavior are you looking for from i801_smbus?  Decline to claim
> the device?  Try to use the device without interrupts?  Try to figure
> out an interrupt in some other way?
>
> I'm not 100% sure that 890e4847587f does the right thing by preventing
> a driver from claiming a device where we can't set up an IRQ.  It's
> conceivable that a driver could still operate a device even without an
> IRQ.
>
>>>   [   33.180145] ixgbe 0000:5a:00.0: Multiq[   33.240538] ixgbe 0000:5a:00.0: (PCI Express:03:e0
>>>   [   33.280826] ixgbe 0000:5a:00.0: MAC: 3, PHY: 0, PBA No: 000000-000
>>>
>>> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
>>> ---
>>>   drivers/acpi/pci_irq.c | 10 +++++++++-
>>>   1 file changed, 9 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
>>> index d30184c..d2f47f8 100644
>>> --- a/drivers/acpi/pci_irq.c
>>> +++ b/drivers/acpi/pci_irq.c
>>> @@ -439,9 +439,17 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
>>>   		if (acpi_isa_register_gsi(dev))
>>>   			dev_warn(&dev->dev, "PCI INT %c: no GSI\n",
>>>   				 pin_name(pin));
>>> +		rc = 0;
>>> +		/*
>>> +		 * Excluding the BIOS report the value 255, which meaning
>>> +		 * "unknown" or "no connection" in PCI Local Bus Specification
>>> +		 * Revision 3.0 February 3, 2004, P223.
>>
>> You mean the footnote on page 223 talking about the Interrupt Line values, right?
>>
>>> +		 */
>>> +		if (dev->irq == 0xFF)
>>> +			rc = -EINVAL;
>>>
>>>   		kfree(entry);
>>> -		return 0;
>>> +		return rc;
>>>   	}
>>>
>>>   	rc = acpi_register_gsi(&dev->dev, gsi, triggering, polarity);
>>>
>>
>> Well, if you look at acpi_isa_register_gsi(), you'll see that it
>> actually does the check you're adding, so maybe the following should
>> be done instead?
>>
>> ---
>>   drivers/acpi/pci_irq.c |    5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> Index: linux-pm/drivers/acpi/pci_irq.c
>> ===================================================================
>> --- linux-pm.orig/drivers/acpi/pci_irq.c
>> +++ linux-pm/drivers/acpi/pci_irq.c
>> @@ -436,12 +436,13 @@ int acpi_pci_irq_enable(struct pci_dev *
>>   	 * driver reported one, then use it. Exit in any case.
>>   	 */
>>   	if (gsi < 0) {
>> -		if (acpi_isa_register_gsi(dev))
>> +		rc = acpi_isa_register_gsi(dev);
>> +		if (rc)
>>   			dev_warn(&dev->dev, "PCI INT %c: no GSI\n",
>>   				 pin_name(pin));
>>
>>   		kfree(entry);
>> -		return 0;
>> +		return rc;
>>   	}
>>
>>   	rc = acpi_register_gsi(&dev->dev, gsi, triggering, polarity);
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
> .
>

-- 
Yours Sincerely,

Cao jin