2005-04-16 15:20:36 -07:00
/*
* include / asm - s390 / io . h
*
* S390 version
* Copyright ( C ) 1999 IBM Deutschland Entwicklung GmbH , IBM Corporation
* Author ( s ) : Martin Schwidefsky ( schwidefsky @ de . ibm . com )
*
* Derived from " include/asm-i386/io.h "
*/
# ifndef _S390_IO_H
# define _S390_IO_H
# include <asm/page.h>
# define IO_SPACE_LIMIT 0xffffffff
/*
* Change virtual addresses to physical addresses and vv .
* These are pretty trivial
*/
2005-11-08 21:34:42 -08:00
static inline unsigned long virt_to_phys ( volatile void * address )
2005-04-16 15:20:36 -07:00
{
unsigned long real_address ;
2006-09-28 16:56:43 +02:00
asm volatile (
" lra %0,0(%1) \n "
" jz 0f \n "
" la %0,0 \n "
2005-04-16 15:20:36 -07:00
" 0: "
2006-09-28 16:56:43 +02:00
: " =a " ( real_address ) : " a " ( address ) : " cc " ) ;
2005-04-16 15:20:36 -07:00
return real_address ;
}
2005-11-08 21:34:42 -08:00
static inline void * phys_to_virt ( unsigned long address )
2005-04-16 15:20:36 -07:00
{
2007-02-12 15:49:57 +01:00
return ( void * ) address ;
2005-04-16 15:20:36 -07:00
}
s390: allow absolute memory access for /dev/mem
Currently dev/mem for s390 provides only real memory access. This means
that the CPU prefix pages are swapped. The prefix swap for real memory
works as follows:
Each CPU owns a prefix register that points to a page aligned memory
location "P". If this CPU accesses the address range [0,0x1fff], it is
translated by the hardware to [P,P+0x1fff]. Accordingly if this CPU
accesses the address range [P,P+0x1fff], it is translated by the hardware
to [0,0x1fff]. Therefore, if [P,P+0x1fff] or [0,0x1fff] is read from
the current /dev/mem device, the incorrectly swapped memory content is
returned.
With this patch the /dev/mem architecture code is modified to provide
absolute memory access. This is done via the arch specific functions
xlate_dev_mem_ptr() and unxlate_dev_mem_ptr(). For swapped pages on
s390 the function xlate_dev_mem_ptr() now returns a new buffer with a
copy of the requested absolute memory. In case the buffer was allocated,
the unxlate_dev_mem_ptr() function frees it after /dev/mem code has
called copy_to_user().
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-05-09 16:27:36 +02:00
void * xlate_dev_mem_ptr ( unsigned long phys ) ;
void unxlate_dev_mem_ptr ( unsigned long phys , void * addr ) ;
2005-04-16 15:20:36 -07:00
/*
* Convert a virtual cached pointer to an uncached pointer
*/
# define xlate_dev_kmem_ptr(p) p
# endif