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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [include/] [asm-m68knommu/] [shm.h] - Blame information for rev 1765

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1 1633 jcastillo
#ifndef _M68K_SHM_H
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#define _M68K_SHM_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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#define SHM_ID_SHIFT    9
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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 /* _M68K_SHM_H */

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