diff mbox series

[F,1/1] s390/pci: Fix unexpected write combine on resource

Message ID 20200309063002.717325-2-frank.heimes@canonical.com
State New
Headers show
Series ZPCI used write back addresses by default but should use write through (LP: 1866162) | expand

Commit Message

Frank Heimes March 9, 2020, 6:30 a.m. UTC 
From: Niklas Schnelle <schnelle@linux.ibm.com>

BugLink: https://bugs.launchpad.net/bugs/1866162

In the initial MIO support introduced in

commit 71ba41c9b1d9 ("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: 71ba41c9b1d9 ("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>
(cherry picked from commit df057c914a9c219ac8b8ed22caf7da2f80c1fe26)
Signed-off-by: Frank Heimes <frank.heimes@canonical.com>
---
 arch/s390/pci/pci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index 5b24fcc9c361..6105b1b6e49b 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -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;