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/* $Id: shmparam.h,v 1.1 2005-12-20 11:32:11 jcastillo Exp $ */

#ifndef _ASMSPARC_SHMPARAM_H

#define _ASMSPARC_SHMPARAM_H

/* address range for shared memory attaches if no address passed to shmat() */

#define SHM_RANGE_START 0x10000000

#define SHM_RANGE_END   0x20000000

/*

 * Format of a swap-entry for shared memory pages currently out in

 * swap space (see also mm/swap.c).

 *

 * SWP_TYPE = SHM_SWP_TYPE

 * SWP_OFFSET is used as follows:

 *

 *  bits 0..6 : id of shared memory segment page belongs to (SHM_ID)

 *  bits 7..21: index of page within shared memory segment (SHM_IDX)

 *              (actually fewer bits get used since SHMMAX is so low)

 */

/*

 * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and

 * there is a static array of size SHMMNI.

 */

#define _SHM_ID_BITS    7

#define SHM_ID_MASK     ((1<<_SHM_ID_BITS)-1)

#define SHM_IDX_SHIFT   (_SHM_ID_BITS)

#define _SHM_IDX_BITS   15

#define SHM_IDX_MASK    ((1<<_SHM_IDX_BITS)-1)

/*

 * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and

 * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).

 */

#define SHMMAX (1024 * 1024)            /* max shared seg size (bytes) */

#define SHMMIN 1 /* really PAGE_SIZE */ /* min shared seg size (bytes) */

#define SHMMNI (1<<_SHM_ID_BITS)        /* max num of segs system wide */

#define SHMALL                          /* max shm system wide (pages) */ \

        (1<<(_SHM_IDX_BITS+_SHM_ID_BITS))

#define SHMLBA PAGE_SIZE                /* attach addr a multiple of this */

#define SHMSEG SHMMNI                   /* max shared segs per process */

#endif /* _ASMSPARC_SHMPARAM_H */