On Mon, Mar 27, 2017 at 10:49:35AM +0100, Lorenzo Pieralisi wrote: > Current ECAM kernel implementation uses ioremap() to map the ECAM > configuration space memory region; this is not safe in that on some > architectures the ioremap interface provides mappings that allow posted > write transactions. This, as highlighted in the PCIe specifications > (4.0 - Rev0.3, "Ordering Considerations for the Enhanced Configuration > Address Mechanism"), can create ordering issues for software because > posted writes transactions on the CPU host bus are non posted in the > PCI express fabric. > > Update the ioremap() interface to use ioremap_nopost() whose > mapping attributes guarantee that non-posted writes transactions > are issued for memory writes within the ECAM memory mapped address > region. > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx> > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > --- > drivers/pci/ecam.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) Acked-by: Will Deacon <will.deacon@xxxxxxx> Will
