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Diffstat (limited to 'include/asm-m68k/shmparam.h')
-rw-r--r-- | include/asm-m68k/shmparam.h | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/include/asm-m68k/shmparam.h b/include/asm-m68k/shmparam.h new file mode 100644 index 000000000..d9e6a9e05 --- /dev/null +++ b/include/asm-m68k/shmparam.h @@ -0,0 +1,44 @@ +#ifndef _M68K_SHMPARAM_H +#define _M68K_SHMPARAM_H + +/* address range for shared memory attaches if no address passed to shmat() */ +#define SHM_RANGE_START 0xC0000000 +#define SHM_RANGE_END 0xD0000000 + +/* + * 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)) +#define SHMLBA PAGE_SIZE /* attach addr a multiple of this */ +#define SHMSEG SHMMNI /* max shared segs per process */ + +#endif /* _M68K_SHMPARAM_H */ |