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commit52d04d4081upstream. When running without MIO support, with pci=nomio or for devices which are not MIO-capable the zPCI subsystem generates pseudo-MMIO addresses to allow access to PCI BARs via MMIO based Linux APIs even though the platform uses function handles and BAR numbers. This is done by stashing an index into our global IOMAP array which contains the function handle in the 16 most significant bits of the addresses returned by ioremap() always setting the most significant bit. On the other hand the MIO addresses assigned by the platform for use, while requiring special instructions, allow PCI access with virtually mapped physical addresses. Now the problem is that these MIO addresses and our own pseudo-MMIO addresses may overlap, while functionally this would not be a problem by itself this overlap is detected by common code as both address types are added as resources in the iomem_resource tree. This leads to the overlapping resource claim of either the MIO capable or non-MIO capable devices with being rejected. Since PCI is tightly coupled to the use of the iomem_resource tree, see for example the code for request_mem_region(), we can't reasonably get rid of the overlap being detected by keeping our pseudo-MMIO addresses out of the iomem_resource tree. Instead let's move the range used by our own pseudo-MMIO addresses by starting at (1UL << 62) and only using addresses below (1UL << 63) thus avoiding the range currently used for MIO addresses. Fixes:c7ff0e918a("s390/pci: deal with devices that have no support for MIO instructions") Cc: stable@vger.kernel.org # 5.3+ Reviewed-by: Pierre Morel <pmorel@linux.ibm.com> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.