Commit df057c91 authored Feb 27, 2020 by Niklas Schnelle Committed by Vasily Gorbik Mar 04, 2020

s390/pci: Fix unexpected write combine on resource



In the initial MIO support introduced in

commit 71ba41c9 ("s390/pci: provide support for MIO instructions")

zpci_map_resource() and zpci_setup_resources() default to using the
mio_wb address as the resource's start address. This means users of the
mapping, which includes most drivers, will get write combining on PCI
Stores. This may lead to problems when drivers expect write through
behavior when not using an explicit ioremap_wc().

Cc: stable@vger.kernel.org
Fixes: 71ba41c9 ("s390/pci: provide support for MIO instructions")
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

parent 582b4e55

arch/s390/pci/pci.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -424,7 +424,7 @@ static void zpci_map_resources(struct pci_dev *pdev)

		if (zpci_use_mio(zdev))
		pdev->resource[i].start =
		(resource_size_t __force) zdev->bars[i].mio_wb;
		(resource_size_t __force) zdev->bars[i].mio_wt;
		else
		pdev->resource[i].start = (resource_size_t __force)
		pci_iomap_range_fh(pdev, i, 0, 0);
		@@ -531,7 +531,7 @@ static int zpci_setup_bus_resources(struct zpci_dev *zdev,
		flags \|= IORESOURCE_MEM_64;

		if (zpci_use_mio(zdev))
		addr = (unsigned long) zdev->bars[i].mio_wb;
		addr = (unsigned long) zdev->bars[i].mio_wt;
		else
		addr = ZPCI_ADDR(entry);
		size = 1UL << zdev->bars[i].size;

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