Commit 576ebd74 authored May 21, 2013 by Michael Holzheu Committed by Martin Schwidefsky May 22, 2013

kernel: Fix s390 absolute memory access for /dev/mem



On s390 the prefix page and absolute zero pages are not correctly
returned when reading /dev/mem. The reason is that the s390 asm/io.h
file includes the asm-generic/io.h file which then defines
xlate_dev_mem_ptr() and therefore overwrites the s390 specific
version that does the correct swap operation for prefix and absolute
zero pages. The problem is a regression that was introduced with git
commit cd248341 (s390/pci: base support).

To fix the problem add "#ifndef xlate_dev_mem_ptr" in asm-generic/io.h
and "#define xlate_dev_mem_ptr" in asm/io.h. This ensures that the
s390 version is used. For completeness also add the "#ifndef"
construct for xlate_dev_kmem_ptr().

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

parent abd9a0c3

arch/s390/include/asm/io.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -36,6 +36,7 @@ static inline void * phys_to_virt(unsigned long address)
		}

		void *xlate_dev_mem_ptr(unsigned long phys);
		#define xlate_dev_mem_ptr xlate_dev_mem_ptr
		void unxlate_dev_mem_ptr(unsigned long phys, void *addr);

		/*

include/asm-generic/io.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -343,8 +343,12 @@ extern void ioport_unmap(void __iomem *p);
		#endif /* CONFIG_GENERIC_IOMAP */
		#endif /* CONFIG_HAS_IOPORT */

		#ifndef xlate_dev_kmem_ptr
		#define xlate_dev_kmem_ptr(p) p
		#endif
		#ifndef xlate_dev_mem_ptr
		#define xlate_dev_mem_ptr(p) __va(p)
		#endif

		#ifdef CONFIG_VIRT_TO_BUS
		#ifndef virt_to_bus