1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
33 lines
1.0 KiB
C
33 lines
1.0 KiB
C
#ifndef _H8300_SHM_H
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#define _H8300_SHM_H
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#include <linux/config.h>
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/* format of page table entries that correspond to shared memory pages
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currently out in swap space (see also mm/swap.c):
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bits 0-1 (PAGE_PRESENT) is = 0
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bits 8..2 (SWP_TYPE) are = SHM_SWP_TYPE
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bits 31..9 are used like this:
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bits 15..9 (SHM_ID) the id of the shared memory segment
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bits 30..16 (SHM_IDX) the index of the page within the shared memory segment
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(actually only bits 25..16 get used since SHMMAX is so low)
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bit 31 (SHM_READ_ONLY) flag whether the page belongs to a read-only attach
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*/
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/* on the m68k both bits 0 and 1 must be zero */
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/* format on the sun3 is similar, but bits 30, 31 are set to zero and all
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others are reduced by 2. --m */
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#ifndef CONFIG_SUN3
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#define SHM_ID_SHIFT 9
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#else
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#define SHM_ID_SHIFT 7
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#endif
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#define _SHM_ID_BITS 7
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#define SHM_ID_MASK ((1<<_SHM_ID_BITS)-1)
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#define SHM_IDX_SHIFT (SHM_ID_SHIFT+_SHM_ID_BITS)
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#define _SHM_IDX_BITS 15
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#define SHM_IDX_MASK ((1<<_SHM_IDX_BITS)-1)
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#endif /* _H8300_SHM_H */
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