Currently, when the sysfs attributes for PCI resources are added dynamically, the mmap() callback will only ever be set when the underlying resource (a given BAR) has either the IORESOURCE_MEM (which currently is implied) or IORESOURCE_IO flag set and where the latter requires that the underlying architecture supports mmap() for I/O BARs, otherwise the callbacks are set to NULL and any attempt to read from such sysfs attribute will inherently fail. Following the conversion to the static sysfs objects, the mmap() callbacks will be always set for a given binary attribute (a particular sysfs object). Thus, a check is added to the pci_mmap_resource() function to ensure that a read against the underlying resource is supported and that either the IORESOURCE_MEM or IORESOURCE_IO flag is set with the platform supporting mmap() for I/O BARs as required. Signed-off-by: Krzysztof Wilczyński <kw@xxxxxxxxx> --- drivers/pci/pci-sysfs.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index e151d635fe04..2031b5da6bcf 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1051,6 +1051,10 @@ static int pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr, if (ret) return ret; + if (!(res->flags & IORESOURCE_MEM || + ((res->flags & IORESOURCE_IO) && arch_can_pci_mmap_io()))) + return -EIO; + if (res->flags & IORESOURCE_MEM && iomem_is_exclusive(res->start)) return -EINVAL; -- 2.33.0
