include/asm-sparc64/shmparam.h

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 1 /* $Id: shmparam.h,v 1.3 1998/09/28 07:15:03 jj Exp $ */
 2 #ifndef _ASMSPARC64_SHMPARAM_H
 3 #define _ASMSPARC64_SHMPARAM_H
 4
 5 /* XXX Redo most of this... */
 6
 7 /* address range for shared memory attaches if no address passed to shmat() */
 8 #define SHM_RANGE_START 0x10000000
 9 #define SHM_RANGE_END 0x20000000
 10
 11 /*
 12  * Format of a swap-entry for shared memory pages currently out in
 13  * swap space (see also mm/swap.c).
 14  *
 15  * SWP_TYPE = SHM_SWP_TYPE
 16  * SWP_OFFSET is used as follows:
 17  *
 18  * bits 0..6 : id of shared memory segment page belongs to (SHM_ID)
 19  * bits 7..21: index of page within shared memory segment (SHM_IDX)
 20  * (actually fewer bits get used since SHMMAX is so low)
 21  */
 22
 23 /*
 24  * Keep _SHM_ID_BITS as low as possible since SHMMNI depends on it and
 25  * there is a static array of size SHMMNI.
 26  */
 27 #define _SHM_ID_BITS 7
 28 #define SHM_ID_MASK ((1<<_SHM_ID_BITS)-1)
 29
 30 #define SHM_IDX_SHIFT (_SHM_ID_BITS)
 31 #define _SHM_IDX_BITS 15
 32 #define SHM_IDX_MASK ((1<<_SHM_IDX_BITS)-1)
 33
 34 /*
 35  * _SHM_ID_BITS + _SHM_IDX_BITS must be <= 24 on the i386 and
 36  * SHMMAX <= (PAGE_SIZE << _SHM_IDX_BITS).
 37  */
 38
 39 #define SHMMAX 0x1000000/* max shared seg size (bytes) */
 40 #define SHMMIN 1/* really PAGE_SIZE *//* min shared seg size (bytes) */
 41 #define SHMMNI (1<<_SHM_ID_BITS)/* max num of segs system wide */
 42 #define SHMALL/* max shm system wide (pages) */ \
 43  (1<<(_SHM_IDX_BITS+_SHM_ID_BITS))
 44 #define SHMLBA (PAGE_SIZE<<1)/* attach addr a multiple of this */
 45 #define SHMSEG SHMMNI/* max shared segs per process */
 46
 47 #endif/* _ASMSPARC64_SHMPARAM_H */