[PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.

[PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.

[Yazen Ghannam]

From: Yazen Ghannam <yazen.ghannam@amd.com>

Currently, aer_service_init() checks if AER is available and that
Firmware First handling is not enabled. The _OSC request for AER is
not taken into account when deciding to enable AER in Linux.

We should check that the _OSC control for AER is set. If it's not
then AER should be disabled.

The _OSC control for AER is not requested when APEI Firmware First is
used, so the same condition applies.

Mark AER as disabled if the _OSC request was not made or accepted.

Remove redunant check for aer_acpi_firmware_first() when calling
aer_service_init(), since this is check is already included when
checking the _OSC control.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
---
 drivers/acpi/pci_root.c       | 3 +++
 drivers/pci/pcie/aer/aerdrv.c | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 6fc204a52493..19a625ed8de9 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -512,6 +512,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
 		 */
 		*no_aspm = 1;
 	}
+
+	if (!(requested & control & OSC_PCI_EXPRESS_AER_CONTROL))
+		pci_no_aer();
 }
 
 static int acpi_pci_root_add(struct acpi_device *device,
diff --git a/drivers/pci/pcie/aer/aerdrv.c b/drivers/pci/pcie/aer/aerdrv.c
index 6ff5f5b4f5e6..39bb059777d0 100644
--- a/drivers/pci/pcie/aer/aerdrv.c
+++ b/drivers/pci/pcie/aer/aerdrv.c
@@ -374,7 +374,7 @@ static void aer_error_resume(struct pci_dev *dev)
  */
 static int __init aer_service_init(void)
 {
-	if (!pci_aer_available() || aer_acpi_firmware_first())
+	if (!pci_aer_available())
 		return -ENXIO;
 	return pcie_port_service_register(&aerdriver);
 }
-- 
2.14.1

Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.

[Rafael J. Wysocki]

On Thu, Jan 11, 2018 at 4:03 PM, Yazen Ghannam <Yazen.Ghannam@amd.com> wrote:
> From: Yazen Ghannam <yazen.ghannam@amd.com>
>
> Currently, aer_service_init() checks if AER is available and that
> Firmware First handling is not enabled. The _OSC request for AER is
> not taken into account when deciding to enable AER in Linux.
>
> We should check that the _OSC control for AER is set. If it's not
> then AER should be disabled.
>
> The _OSC control for AER is not requested when APEI Firmware First is
> used, so the same condition applies.
>
> Mark AER as disabled if the _OSC request was not made or accepted.
>
> Remove redunant check for aer_acpi_firmware_first() when calling
> aer_service_init(), since this is check is already included when
> checking the _OSC control.
>
> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> ---
>  drivers/acpi/pci_root.c       | 3 +++
>  drivers/pci/pcie/aer/aerdrv.c | 2 +-
>  2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 6fc204a52493..19a625ed8de9 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -512,6 +512,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
>                  */
>                 *no_aspm = 1;
>         }
> +
> +       if (!(requested & control & OSC_PCI_EXPRESS_AER_CONTROL))

One of the operators above needs to be a && I suppose?

> +               pci_no_aer();
>  }
>
>  static int acpi_pci_root_add(struct acpi_device *device,
> diff --git a/drivers/pci/pcie/aer/aerdrv.c b/drivers/pci/pcie/aer/aerdrv.c
> index 6ff5f5b4f5e6..39bb059777d0 100644
> --- a/drivers/pci/pcie/aer/aerdrv.c
> +++ b/drivers/pci/pcie/aer/aerdrv.c
> @@ -374,7 +374,7 @@ static void aer_error_resume(struct pci_dev *dev)
>   */
>  static int __init aer_service_init(void)
>  {
> -       if (!pci_aer_available() || aer_acpi_firmware_first())
> +       if (!pci_aer_available())
>                 return -ENXIO;
>         return pcie_port_service_register(&aerdriver);
>  }
> --

RE: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.

[Ghannam, Yazen]

> -----Original Message-----
> From: rjwysocki@gmail.com [mailto:rjwysocki@gmail.com] On Behalf Of
> Rafael J. Wysocki
> Sent: Thursday, January 11, 2018 12:39 PM
> To: Ghannam, Yazen <Yazen.Ghannam@amd.com>
> Cc: ACPI Devel Maling List <linux-acpi@vger.kernel.org>; Linux Kernel Mailing
> List <linux-kernel@vger.kernel.org>; Linux PCI <linux-pci@vger.kernel.org>;
> Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Bjorn
> Helgaas <bhelgaas@google.com>; Borislav Petkov <bp@suse.de>
> Subject: Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
> 
> On Thu, Jan 11, 2018 at 4:03 PM, Yazen Ghannam
> <Yazen.Ghannam@amd.com> wrote:
> > From: Yazen Ghannam <yazen.ghannam@amd.com>
> >
> > Currently, aer_service_init() checks if AER is available and that
> > Firmware First handling is not enabled. The _OSC request for AER is
> > not taken into account when deciding to enable AER in Linux.
> >
> > We should check that the _OSC control for AER is set. If it's not
> > then AER should be disabled.
> >
> > The _OSC control for AER is not requested when APEI Firmware First is
> > used, so the same condition applies.
> >
> > Mark AER as disabled if the _OSC request was not made or accepted.
> >
> > Remove redunant check for aer_acpi_firmware_first() when calling
> > aer_service_init(), since this is check is already included when
> > checking the _OSC control.
> >
> > Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> > ---
> >  drivers/acpi/pci_root.c       | 3 +++
> >  drivers/pci/pcie/aer/aerdrv.c | 2 +-
> >  2 files changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> > index 6fc204a52493..19a625ed8de9 100644
> > --- a/drivers/acpi/pci_root.c
> > +++ b/drivers/acpi/pci_root.c
> > @@ -512,6 +512,9 @@ static void negotiate_os_control(struct
> acpi_pci_root *root, int *no_aspm)
> >                  */
> >                 *no_aspm = 1;
> >         }
> > +
> > +       if (!(requested & control & OSC_PCI_EXPRESS_AER_CONTROL))
> 
> One of the operators above needs to be a && I suppose?
> 

It's a 3-way bitwise AND to check that OSC_PCI_EXPRESS_AER_CONTROL is
set in both "requested" and "control".

IOW, we check if AER was requested by the OS and that the platform
granted the request.

Thanks,
Yazen

Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.

[Rafael J. Wysocki]

On Thu, Jan 11, 2018 at 6:48 PM, Ghannam, Yazen <Yazen.Ghannam@amd.com> wrote:
>> -----Original Message-----
>> From: rjwysocki@gmail.com [mailto:rjwysocki@gmail.com] On Behalf Of
>> Rafael J. Wysocki
>> Sent: Thursday, January 11, 2018 12:39 PM
>> To: Ghannam, Yazen <Yazen.Ghannam@amd.com>
>> Cc: ACPI Devel Maling List <linux-acpi@vger.kernel.org>; Linux Kernel Mailing
>> List <linux-kernel@vger.kernel.org>; Linux PCI <linux-pci@vger.kernel.org>;
>> Rafael J. Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Bjorn
>> Helgaas <bhelgaas@google.com>; Borislav Petkov <bp@suse.de>
>> Subject: Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.
>>
>> On Thu, Jan 11, 2018 at 4:03 PM, Yazen Ghannam
>> <Yazen.Ghannam@amd.com> wrote:
>> > From: Yazen Ghannam <yazen.ghannam@amd.com>
>> >
>> > Currently, aer_service_init() checks if AER is available and that
>> > Firmware First handling is not enabled. The _OSC request for AER is
>> > not taken into account when deciding to enable AER in Linux.
>> >
>> > We should check that the _OSC control for AER is set. If it's not
>> > then AER should be disabled.
>> >
>> > The _OSC control for AER is not requested when APEI Firmware First is
>> > used, so the same condition applies.
>> >
>> > Mark AER as disabled if the _OSC request was not made or accepted.
>> >
>> > Remove redunant check for aer_acpi_firmware_first() when calling
>> > aer_service_init(), since this is check is already included when
>> > checking the _OSC control.
>> >
>> > Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
>> > ---
>> >  drivers/acpi/pci_root.c       | 3 +++
>> >  drivers/pci/pcie/aer/aerdrv.c | 2 +-
>> >  2 files changed, 4 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>> > index 6fc204a52493..19a625ed8de9 100644
>> > --- a/drivers/acpi/pci_root.c
>> > +++ b/drivers/acpi/pci_root.c
>> > @@ -512,6 +512,9 @@ static void negotiate_os_control(struct
>> acpi_pci_root *root, int *no_aspm)
>> >                  */
>> >                 *no_aspm = 1;
>> >         }
>> > +
>> > +       if (!(requested & control & OSC_PCI_EXPRESS_AER_CONTROL))
>>
>> One of the operators above needs to be a && I suppose?
>>
>
> It's a 3-way bitwise AND to check that OSC_PCI_EXPRESS_AER_CONTROL is
> set in both "requested" and "control".
>
> IOW, we check if AER was requested by the OS and that the platform
> granted the request.

OK

I'll queue this up if Bjorn doesn't object, unless Bjorn wants to
apply it himself.

Thanks,
Rafael

Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.

[Borislav Petkov]

On Thu, Jan 11, 2018 at 07:03:23PM +0100, Rafael J. Wysocki wrote:
> >> > +       if (!(requested & control & OSC_PCI_EXPRESS_AER_CONTROL))
> >>
> >> One of the operators above needs to be a && I suppose?
> >>
> >
> > It's a 3-way bitwise AND to check that OSC_PCI_EXPRESS_AER_CONTROL is
> > set in both "requested" and "control".
> >
> > IOW, we check if AER was requested by the OS and that the platform
> > granted the request.
> 
> OK

This definitely needs a comment - people will keep tripping over this.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
-- 

Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.

[Rafael J. Wysocki]

On Thu, Jan 11, 2018 at 8:04 PM, Borislav Petkov <bp@suse.de> wrote:
> On Thu, Jan 11, 2018 at 07:03:23PM +0100, Rafael J. Wysocki wrote:
>> >> > +       if (!(requested & control & OSC_PCI_EXPRESS_AER_CONTROL))
>> >>
>> >> One of the operators above needs to be a && I suppose?
>> >>
>> >
>> > It's a 3-way bitwise AND to check that OSC_PCI_EXPRESS_AER_CONTROL is
>> > set in both "requested" and "control".
>> >
>> > IOW, we check if AER was requested by the OS and that the platform
>> > granted the request.
>>
>> OK
>
> This definitely needs a comment - people will keep tripping over this.

Fair enough.

Re: [PATCH] PCI/ACPI: Disable AER when _OSC control bit is clear.

[Bjorn Helgaas]

On Thu, Jan 11, 2018 at 09:03:16AM -0600, Yazen Ghannam wrote:
> From: Yazen Ghannam <yazen.ghannam@amd.com>
> 
> Currently, aer_service_init() checks if AER is available and that
> Firmware First handling is not enabled. The _OSC request for AER is
> not taken into account when deciding to enable AER in Linux.
> 
> We should check that the _OSC control for AER is set. If it's not
> then AER should be disabled.
> 
> The _OSC control for AER is not requested when APEI Firmware First is
> used, so the same condition applies.
> 
> Mark AER as disabled if the _OSC request was not made or accepted.
> 
> Remove redunant check for aer_acpi_firmware_first() when calling
> aer_service_init(), since this is check is already included when
> checking the _OSC control.

s/redunant/redundant/

The concept seems right to me.  Please add a citation to the relevant spec
section.  I think this is somewhere in the PCI Firmware spec.

> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> ---
>  drivers/acpi/pci_root.c       | 3 +++
>  drivers/pci/pcie/aer/aerdrv.c | 2 +-
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index 6fc204a52493..19a625ed8de9 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -512,6 +512,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
>  		 */
>  		*no_aspm = 1;
>  	}
> +
> +	if (!(requested & control & OSC_PCI_EXPRESS_AER_CONTROL))
> +		pci_no_aer();
>  }
>  
>  static int acpi_pci_root_add(struct acpi_device *device,
> diff --git a/drivers/pci/pcie/aer/aerdrv.c b/drivers/pci/pcie/aer/aerdrv.c
> index 6ff5f5b4f5e6..39bb059777d0 100644
> --- a/drivers/pci/pcie/aer/aerdrv.c
> +++ b/drivers/pci/pcie/aer/aerdrv.c
> @@ -374,7 +374,7 @@ static void aer_error_resume(struct pci_dev *dev)
>   */
>  static int __init aer_service_init(void)
>  {
> -	if (!pci_aer_available() || aer_acpi_firmware_first())
> +	if (!pci_aer_available())
>  		return -ENXIO;
>  	return pcie_port_service_register(&aerdriver);
>  }
> -- 
> 2.14.1
> 
> --
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