1#ifndef _M68K_SHM_H 2#define _M68K_SHM_H 3 4#include <linux/config.h> 5 6/* format of page table entries that correspond to shared memory pages 7 currently out in swap space (see also mm/swap.c): 8 bits 0-1 (PAGE_PRESENT) is = 0 9 bits 8..2 (SWP_TYPE) are = SHM_SWP_TYPE 10 bits 31..9 are used like this: 11 bits 15..9 (SHM_ID) the id of the shared memory segment 12 bits 30..16 (SHM_IDX) the index of the page within the shared memory segment 13 (actually only bits 25..16 get used since SHMMAX is so low) 14 bit 31 (SHM_READ_ONLY) flag whether the page belongs to a read-only attach 15*/ 16/* on the m68k both bits 0 and 1 must be zero */ 17/* format on the sun3 is similar, but bits 30, 31 are set to zero and all 18 others are reduced by 2. --m */ 19 20#ifndef CONFIG_SUN3 21#define SHM_ID_SHIFT 9 22#else 23#define SHM_ID_SHIFT 7 24#endif 25#define _SHM_ID_BITS 7 26#define SHM_ID_MASK ((1<<_SHM_ID_BITS)-1) 27 28#define SHM_IDX_SHIFT (SHM_ID_SHIFT+_SHM_ID_BITS) 29#define _SHM_IDX_BITS 15 30#define SHM_IDX_MASK ((1<<_SHM_IDX_BITS)-1) 31 32#endif /* _M68K_SHM_H */ 33