Messages in this thread |  | | | Subject | Re: Having problem with mmap system call!!! | | From | Alan Cox <> | | Date | Thu, 16 Sep 2004 14:31:36 +0100 |
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On Iau, 2004-09-16 at 15:07, Richard B. Johnson wrote: > if((vp = mmap((caddr_t) HINT, len, PROT, FLAGS, fd, addr)) == SHM_FAIL) > { > fprintf(stderr, "Can't access shared memory\n"); > exit(EXIT_FAILURE);
SHM_FAIL is the wrong error check btw.
It is much better to do this in the driver than do nasty user mode hacks using /dev/mem. When you do it kernel driver side you end up with a cleaner mmap interface, a sensible permissions model and the hardware device pages mapped directly and nicely into the app
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