1 #ifndef _H8300_SHM_H 2 #define _H8300_SHM_H 3 4 5 /* format of page table entries that correspond to shared memory pages 6 currently out in swap space (see also mm/swap.c): 7 bits 0-1 (PAGE_PRESENT) is = 0 8 bits 8..2 (SWP_TYPE) are = SHM_SWP_TYPE 9 bits 31..9 are used like this: 10 bits 15..9 (SHM_ID) the id of the shared memory segment 11 bits 30..16 (SHM_IDX) the index of the page within the shared memory segment 12 (actually only bits 25..16 get used since SHMMAX is so low) 13 bit 31 (SHM_READ_ONLY) flag whether the page belongs to a read-only attach 14 */ 15 /* on the m68k both bits 0 and 1 must be zero */ 16 /* format on the sun3 is similar, but bits 30, 31 are set to zero and all 17 others are reduced by 2. --m */ 18 19 #ifndef CONFIG_SUN3 20 #define SHM_ID_SHIFT 9 21 #else 22 #define SHM_ID_SHIFT 7 23 #endif 24 #define _SHM_ID_BITS 7 25 #define SHM_ID_MASK ((1<<_SHM_ID_BITS)-1) 26 27 #define SHM_IDX_SHIFT (SHM_ID_SHIFT+_SHM_ID_BITS) 28 #define _SHM_IDX_BITS 15 29 #define SHM_IDX_MASK ((1<<_SHM_IDX_BITS)-1) 30 31 #endif /* _H8300_SHM_H */ 32