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

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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>
This commit is contained in:
Michael Holzheu 2013-05-21 16:08:22 +02:00 committed by Martin Schwidefsky
parent abd9a0c360
commit 576ebd7492
2 changed files with 5 additions and 0 deletions
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1
arch/s390/include/asm/io.h
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@ -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);
/*

4
include/asm-generic/io.h
View File

@ -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