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s390/pci: Fix unexpected write combine on resource 

commit df057c914a upstream.

In the initial MIO support introduced in

commit 71ba41c9b1 ("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: 71ba41c9b1 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Niklas Schnelle 2020-02-27 12:17:18 +01:00 committed by Greg Kroah-Hartman
parent c8f3adc406
commit 88fbd1d312
1 changed files with 2 additions and 2 deletions
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4
arch/s390/pci/pci.c
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@ -423,7 +423,7 @@ 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);
@ -530,7 +530,7 @@ 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;