[PATCH 1/1] PCI: Use resource_set_range() that correctly sets ->end

[PATCH 1/1] PCI: Use resource_set_range() that correctly sets ->end

[Ilpo Järvinen]

__pci_read_base() sets resource start and end addresses when resource
is larger than 4G but pci_bus_addr_t or resource_size_t are not capable
of representing 64-bit PCI addresses. This creates a problematic
resource that has non-zero flags but the start and end addresses do not
yield to resource size of 0 but 1.

Replace custom resource addresses setup with resource_set_range()
that correctly sets end address as -1 which results in resource_size()
returning 0.

For consistency, also use resource_set_range() in the other branch that
does size based resource setup.

Fixes: 23b13bc76f35 ("PCI: Fail safely if we can't handle BARs larger than 4GB")
Link: https://lore.kernel.org/all/20251207215359.28895-1-ansuelsmth@gmail.com/T/#m990492684913c5a158ff0e5fc90697d8ad95351b
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/pci/probe.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 124d2d309c58..b8294a2f11f9 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -287,8 +287,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
 		if ((sizeof(pci_bus_addr_t) < 8 || sizeof(resource_size_t) < 8)
 		    && sz64 > 0x100000000ULL) {
 			res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED;
-			res->start = 0;
-			res->end = 0;
+			resource_set_range(res, 0, 0);
 			pci_err(dev, "%s: can't handle BAR larger than 4GB (size %#010llx)\n",
 				res_name, (unsigned long long)sz64);
 			goto out;
@@ -297,8 +296,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
 		if ((sizeof(pci_bus_addr_t) < 8) && l) {
 			/* Above 32-bit boundary; try to reallocate */
 			res->flags |= IORESOURCE_UNSET;
-			res->start = 0;
-			res->end = sz64 - 1;
+			resource_set_range(res, 0, sz64);
 			pci_info(dev, "%s: can't handle BAR above 4GB (bus address %#010llx)\n",
 				 res_name, (unsigned long long)l64);
 			goto out;

base-commit: 43dfc13ca972988e620a6edb72956981b75ab6b0
-- 
2.39.5

Re: [PATCH 1/1] PCI: Use resource_set_range() that correctly sets ->end

[Andy Shevchenko]

On Mon, Dec 08, 2025 at 04:56:54PM +0200, Ilpo Järvinen wrote:
> __pci_read_base() sets resource start and end addresses when resource
> is larger than 4G but pci_bus_addr_t or resource_size_t are not capable
> of representing 64-bit PCI addresses. This creates a problematic
> resource that has non-zero flags but the start and end addresses do not
> yield to resource size of 0 but 1.
> 
> Replace custom resource addresses setup with resource_set_range()
> that correctly sets end address as -1 which results in resource_size()
> returning 0.
> 
> For consistency, also use resource_set_range() in the other branch that
> does size based resource setup.

Since I have been involved in the related discussion and the patch LGTM,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH 1/1] PCI: Use resource_set_range() that correctly sets ->end

[Bjorn Helgaas]

On Mon, Dec 08, 2025 at 04:56:54PM +0200, Ilpo Järvinen wrote:
> __pci_read_base() sets resource start and end addresses when resource
> is larger than 4G but pci_bus_addr_t or resource_size_t are not capable
> of representing 64-bit PCI addresses. This creates a problematic
> resource that has non-zero flags but the start and end addresses do not
> yield to resource size of 0 but 1.
> 
> Replace custom resource addresses setup with resource_set_range()
> that correctly sets end address as -1 which results in resource_size()
> returning 0.
> 
> For consistency, also use resource_set_range() in the other branch that
> does size based resource setup.

IIUC this fixes an ath11k regression (and probably others).  And
typically when booting a 32-bit kernel with a device with a BAR larger
than 4GB?

Christian, is there any dmesg snippet we could include here to help
users diagnose the problem?  I guess the "can't handle BAR larger than
4GB" message is probably one clue.

Are you able to test this and verify that it fixes the regression you
saw?

> Fixes: 23b13bc76f35 ("PCI: Fail safely if we can't handle BARs larger than 4GB")
> Link: https://lore.kernel.org/all/20251207215359.28895-1-ansuelsmth@gmail.com/T/#m990492684913c5a158ff0e5fc90697d8ad95351b
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> Cc: stable@vger.kernel.org
> Cc: Christian Marangi <ansuelsmth@gmail.com>
> ---
>  drivers/pci/probe.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 124d2d309c58..b8294a2f11f9 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -287,8 +287,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
>  		if ((sizeof(pci_bus_addr_t) < 8 || sizeof(resource_size_t) < 8)
>  		    && sz64 > 0x100000000ULL) {
>  			res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED;
> -			res->start = 0;
> -			res->end = 0;
> +			resource_set_range(res, 0, 0);
>  			pci_err(dev, "%s: can't handle BAR larger than 4GB (size %#010llx)\n",
>  				res_name, (unsigned long long)sz64);
>  			goto out;
> @@ -297,8 +296,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
>  		if ((sizeof(pci_bus_addr_t) < 8) && l) {
>  			/* Above 32-bit boundary; try to reallocate */
>  			res->flags |= IORESOURCE_UNSET;
> -			res->start = 0;
> -			res->end = sz64 - 1;
> +			resource_set_range(res, 0, sz64);
>  			pci_info(dev, "%s: can't handle BAR above 4GB (bus address %#010llx)\n",
>  				 res_name, (unsigned long long)l64);
>  			goto out;
> 
> base-commit: 43dfc13ca972988e620a6edb72956981b75ab6b0
> -- 
> 2.39.5
> 

Re: [PATCH 1/1] PCI: Use resource_set_range() that correctly sets ->end

[Christian Marangi]

On Wed, Dec 10, 2025 at 11:13:19AM -0600, Bjorn Helgaas wrote:
> On Mon, Dec 08, 2025 at 04:56:54PM +0200, Ilpo Järvinen wrote:
> > __pci_read_base() sets resource start and end addresses when resource
> > is larger than 4G but pci_bus_addr_t or resource_size_t are not capable
> > of representing 64-bit PCI addresses. This creates a problematic
> > resource that has non-zero flags but the start and end addresses do not
> > yield to resource size of 0 but 1.
> > 
> > Replace custom resource addresses setup with resource_set_range()
> > that correctly sets end address as -1 which results in resource_size()
> > returning 0.
> > 
> > For consistency, also use resource_set_range() in the other branch that
> > does size based resource setup.
> 
> IIUC this fixes an ath11k regression (and probably others).  And
> typically when booting a 32-bit kernel with a device with a BAR larger
> than 4GB?
> 
> Christian, is there any dmesg snippet we could include here to help
> users diagnose the problem?  I guess the "can't handle BAR larger than
> 4GB" message is probably one clue.
> 
> Are you able to test this and verify that it fixes the regression you
> saw?
>

No my regression was on a different section and for AHB cards, no PCI.
(I sent a fix for my regression on the net mailing list)

Could be hard to find a device with 4+ gb of ram that is not x86 or on
an ipq SoC.

> > Fixes: 23b13bc76f35 ("PCI: Fail safely if we can't handle BARs larger than 4GB")
> > Link: https://lore.kernel.org/all/20251207215359.28895-1-ansuelsmth@gmail.com/T/#m990492684913c5a158ff0e5fc90697d8ad95351b
> > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> > Cc: stable@vger.kernel.org
> > Cc: Christian Marangi <ansuelsmth@gmail.com>
> > ---
> >  drivers/pci/probe.c | 6 ++----
> >  1 file changed, 2 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > index 124d2d309c58..b8294a2f11f9 100644
> > --- a/drivers/pci/probe.c
> > +++ b/drivers/pci/probe.c
> > @@ -287,8 +287,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
> >  		if ((sizeof(pci_bus_addr_t) < 8 || sizeof(resource_size_t) < 8)
> >  		    && sz64 > 0x100000000ULL) {
> >  			res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED;
> > -			res->start = 0;
> > -			res->end = 0;
> > +			resource_set_range(res, 0, 0);
> >  			pci_err(dev, "%s: can't handle BAR larger than 4GB (size %#010llx)\n",
> >  				res_name, (unsigned long long)sz64);
> >  			goto out;
> > @@ -297,8 +296,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
> >  		if ((sizeof(pci_bus_addr_t) < 8) && l) {
> >  			/* Above 32-bit boundary; try to reallocate */
> >  			res->flags |= IORESOURCE_UNSET;
> > -			res->start = 0;
> > -			res->end = sz64 - 1;
> > +			resource_set_range(res, 0, sz64);
> >  			pci_info(dev, "%s: can't handle BAR above 4GB (bus address %#010llx)\n",
> >  				 res_name, (unsigned long long)l64);
> >  			goto out;
> > 
> > base-commit: 43dfc13ca972988e620a6edb72956981b75ab6b0
> > -- 
> > 2.39.5
> > 

-- 
	Ansuel

Re: [PATCH 1/1] PCI: Use resource_set_range() that correctly sets ->end

[Bjorn Helgaas]

On Mon, Dec 08, 2025 at 04:56:54PM +0200, Ilpo Järvinen wrote:
> __pci_read_base() sets resource start and end addresses when resource
> is larger than 4G but pci_bus_addr_t or resource_size_t are not capable
> of representing 64-bit PCI addresses. This creates a problematic
> resource that has non-zero flags but the start and end addresses do not
> yield to resource size of 0 but 1.
> 
> Replace custom resource addresses setup with resource_set_range()
> that correctly sets end address as -1 which results in resource_size()
> returning 0.
> 
> For consistency, also use resource_set_range() in the other branch that
> does size based resource setup.
> 
> Fixes: 23b13bc76f35 ("PCI: Fail safely if we can't handle BARs larger than 4GB")
> Link: https://lore.kernel.org/all/20251207215359.28895-1-ansuelsmth@gmail.com/T/#m990492684913c5a158ff0e5fc90697d8ad95351b
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> Cc: stable@vger.kernel.org
> Cc: Christian Marangi <ansuelsmth@gmail.com>

Applied to pci/resource for v6.20, thanks!

> ---
>  drivers/pci/probe.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 124d2d309c58..b8294a2f11f9 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -287,8 +287,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
>  		if ((sizeof(pci_bus_addr_t) < 8 || sizeof(resource_size_t) < 8)
>  		    && sz64 > 0x100000000ULL) {
>  			res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED;
> -			res->start = 0;
> -			res->end = 0;
> +			resource_set_range(res, 0, 0);
>  			pci_err(dev, "%s: can't handle BAR larger than 4GB (size %#010llx)\n",
>  				res_name, (unsigned long long)sz64);
>  			goto out;
> @@ -297,8 +296,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
>  		if ((sizeof(pci_bus_addr_t) < 8) && l) {
>  			/* Above 32-bit boundary; try to reallocate */
>  			res->flags |= IORESOURCE_UNSET;
> -			res->start = 0;
> -			res->end = sz64 - 1;
> +			resource_set_range(res, 0, sz64);
>  			pci_info(dev, "%s: can't handle BAR above 4GB (bus address %#010llx)\n",
>  				 res_name, (unsigned long long)l64);
>  			goto out;
> 
> base-commit: 43dfc13ca972988e620a6edb72956981b75ab6b0
> -- 
> 2.39.5
>