| #ifndef _M68K_SHM_H |
| #define _M68K_SHM_H |
| |
| |
| /* format of page table entries that correspond to shared memory pages |
| currently out in swap space (see also mm/swap.c): |
| bits 0-1 (PAGE_PRESENT) is = 0 |
| bits 8..2 (SWP_TYPE) are = SHM_SWP_TYPE |
| bits 31..9 are used like this: |
| bits 15..9 (SHM_ID) the id of the shared memory segment |
| bits 30..16 (SHM_IDX) the index of the page within the shared memory segment |
| (actually only bits 25..16 get used since SHMMAX is so low) |
| bit 31 (SHM_READ_ONLY) flag whether the page belongs to a read-only attach |
| */ |
| /* on the m68k both bits 0 and 1 must be zero */ |
| /* format on the sun3 is similar, but bits 30, 31 are set to zero and all |
| others are reduced by 2. --m */ |
| |
| #ifndef CONFIG_SUN3 |
| #define SHM_ID_SHIFT 9 |
| #else |
| #define SHM_ID_SHIFT 7 |
| #endif |
| #define _SHM_ID_BITS 7 |
| #define SHM_ID_MASK ((1<<_SHM_ID_BITS)-1) |
| |
| #define SHM_IDX_SHIFT (SHM_ID_SHIFT+_SHM_ID_BITS) |
| #define _SHM_IDX_BITS 15 |
| #define SHM_IDX_MASK ((1<<_SHM_IDX_BITS)-1) |
| |
| #endif /* _M68K_SHM_H */ |
