ARC: Add support for ioremap_prot API

Implement ioremap_prot() to allow mapping IO memory with variable
protection
via TLB.

Implementing this allows the /dev/mem driver to use its generic access()
VMA callback, which in turn allows ptrace to examine data in memory
mapped regions mapped via /dev/mem, such as Arc DCCM.

The end result is that it is possible to examine values of variables
placed into DCCM in user space programs via GDB.

CC: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
CC: Noam Camus <noamc@ezchip.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/include/asm/page.h b/arch/arc/include/asm/page.h
index dfe1f8a..bdf5461 100644
--- a/arch/arc/include/asm/page.h
+++ b/arch/arc/include/asm/page.h
@@ -48,6 +48,8 @@
 #define __pgd(x)        ((pgd_t) { (x) })
 #define __pgprot(x)     ((pgprot_t) { (x) })
 
+#define pte_pgprot(x) __pgprot(pte_val(x))
+
 #else /* !STRICT_MM_TYPECHECKS */
 
 typedef unsigned long pte_t;
@@ -60,6 +62,7 @@
 #define pgprot_val(x)	(x)
 #define __pte(x)	(x)
 #define __pgprot(x)	(x)
+#define pte_pgprot(x)	(x)
 
 #endif