52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
/*
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* mmap.c
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*/
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#include <stdint.h>
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#include <errno.h>
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#include <sys/syscall.h>
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#include <sys/mman.h>
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#include <asm/page.h> /* For PAGE_SHIFT */
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#if defined(__sparc__)
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# define MMAP2_SHIFT 12 /* Fixed by syscall definition */
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#else
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# define MMAP2_SHIFT PAGE_SHIFT
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#endif
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#define MMAP2_MASK ((1UL << MMAP2_SHIFT)-1)
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/*
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* Prefer mmap2() over mmap(), except on the architectures listed
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*/
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#if defined(__NR_mmap2) && !defined(__sparc__) && !defined(__ia64__) && !defined(__powerpc64__)
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/* This architecture uses mmap2() */
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static inline _syscall6(void *,mmap2,void *,start,size_t,length,int,prot,int,flags,int,fd,off_t,offset);
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/* The Linux mmap2() system call takes a page offset as the offset argument.
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We need to make sure we have the proper conversion in place. */
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void *mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
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{
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if ( offset & MMAP2_MASK ) {
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errno = EINVAL;
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return MAP_FAILED;
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}
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return mmap2(start, length, prot, flags, fd, (size_t)offset >> MMAP2_SHIFT);
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}
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#else
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/* This architecture uses a plain mmap() system call */
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/* Only use this for architectures where mmap() is a real 6-argument system call! */
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_syscall6(void *,mmap,void *,start,size_t,length,int,prot,int,flags,int,fd,off_t,offset)
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#endif
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