Re: Having problem with mmap system call!!!

[Alan Cox]

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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