Linux with MMU acessing registers

[Altera_Forum]

Hello i need to acess my registers from userspace, i am developing a 

critical timing application and i can't consider the time needed to call the device driver and read my timestamp register. I need to read my timestamp register from userspace, how can i do that? I know that 0x8 is for uncached, therefore peripherals adresses will have the 8 in the adress.  I am trying to use inl(0x000024e0 (my adress), 0); however i get a segmentation fault... i tried to include io.h but with no sucess # define inl(addr)  ({  unsigned int __res; __asm__ __volatile__(  "ldwio %0, 0(%1)"  : "=r"(__res)  : "r" (addr));  __res;  })  //----------------------------------------------------------------------- # define inb(addr)  ({  unsigned int __res; __asm__ __volatile__(  "ldbio %0, 0(%1)"  : "=r"(__res)  : "r" (addr));  __res;  })  //----------------------------------------------------------------------- # define outl(b,addr)  ({  __asm__ __volatile__(  "stwio %0, 0(%1)"  : : "r"(, "r" (addr));  })  //----------------------------------------------------------------------- # define outw(b,addr)  ({  __asm__ __volatile__(  "sthio %0, 0(%1)"  : : "r"(, "r" (addr));  })  //----------------------------------------------------------------------- # define outb(b,addr)  ({  __asm__ __volatile__(  "stbio %0, 0(%1)"  : : "r"(, "r" (addr));  })

[Altera_Forum]

Please don't cross-post between the mailing list and the nios2-dev list. Or if you do so, please at least link put a link to the other, so people searching for answers to the same or similar questions can find it in the other place too. 

 As already stated on nios2-dev, this won't work (for obvious reasons). Please see http://article.gmane.org/gmane.linux.uclinux.nios2.devel/189 for the full answer.

[Altera_Forum]

Okay, is there any easy way to acess the list archive?

[Altera_Forum]

Yes, there is. Either the mailman archive at http://sopc.et.ntust.edu.tw/pipermail/nios2-dev/ or at gmane (only massages since around beginning of june 2011): http://news.gmane.org/gmane.linux.uclinux.nios2.devel

[Altera_Forum]

This is my final code 

   memfd = open("/dev/mem", O_RDWR | O_SYNC );  if (memfd < 0)  {  log_msg("Cannot open /dev/mem\n");  exit(1);  }  pgoff = (unsigned int) (MENOS_BASE & (sysconf(_SC_PAGE_SIZE)-1));  map_len = 16 + pgoff;  mapped = mmap(NULL, map_len, (PROT_READ | PROT_WRITE), MAP_SHARED, memfd, MENOS_BASE - pgoff);   if (mapped == MAP_FAILED )  {  log_msg("Cannot map registers\n");  }  ts_my = mapped + pgoff;   inl(ts_my);