summaryrefslogtreecommitdiffstats
path: root/include/asm-mips/shmparam.h
blob: b2441c81a69680b773d4714c404fd4232ce36af5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
#ifndef __ASM_MIPS_SHMPARAM_H
#define __ASM_MIPS_SHMPARAM_H

/* address range for shared memory attaches if no address passed to shmat() */
#define SHM_RANGE_START	0x50000000
#define SHM_RANGE_END	0x60000000

/*
 * 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 0x1000000		/* 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))
/*
 * This constant is very large but the ABI in it's wisdom says ...
 */
#define	SHMLBA 0x40000			/* attach addr a multiple of this */
#define SHMSEG SHMMNI			/* max shared segs per process */

#endif /* __ASM_MIPS_SHMPARAM_H */