ARM: 8640/1: Add support for CONFIG_DEBUG_VIRTUAL

x86 has an option: CONFIG_DEBUG_VIRTUAL to do additional checks on
virt_to_phys calls. The goal is to catch users who are calling
virt_to_phys on non-linear addresses immediately. This includes caller
using __virt_to_phys() on image addresses instead of __pa_symbol(). This
is a generally useful debug feature to spot bad code (particulary in
drivers).

Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index bee7511..c30d0d8 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -213,7 +213,7 @@
 	: "r" (x), "I" (__PV_BITS_31_24)		\
 	: "cc")
 
-static inline phys_addr_t __virt_to_phys(unsigned long x)
+static inline phys_addr_t __virt_to_phys_nodebug(unsigned long x)
 {
 	phys_addr_t t;
 
@@ -245,7 +245,7 @@
 #define PHYS_OFFSET	PLAT_PHYS_OFFSET
 #define PHYS_PFN_OFFSET	((unsigned long)(PHYS_OFFSET >> PAGE_SHIFT))
 
-static inline phys_addr_t __virt_to_phys(unsigned long x)
+static inline phys_addr_t __virt_to_phys_nodebug(unsigned long x)
 {
 	return (phys_addr_t)x - PAGE_OFFSET + PHYS_OFFSET;
 }
@@ -261,6 +261,16 @@
 	((((unsigned long)(kaddr) - PAGE_OFFSET) >> PAGE_SHIFT) + \
 	 PHYS_PFN_OFFSET)
 
+#define __pa_symbol_nodebug(x)	__virt_to_phys_nodebug((x))
+
+#ifdef CONFIG_DEBUG_VIRTUAL
+extern phys_addr_t __virt_to_phys(unsigned long x);
+extern phys_addr_t __phys_addr_symbol(unsigned long x);
+#else
+#define __virt_to_phys(x)	__virt_to_phys_nodebug(x)
+#define __phys_addr_symbol(x)	__pa_symbol_nodebug(x)
+#endif
+
 /*
  * These are *only* valid on the kernel direct mapped RAM memory.
  * Note: Drivers should NOT use these.  They are the wrong
@@ -283,6 +293,7 @@
  * Drivers should NOT use these either.
  */
 #define __pa(x)			__virt_to_phys((unsigned long)(x))
+#define __pa_symbol(x)		__phys_addr_symbol(RELOC_HIDE((unsigned long)(x), 0))
 #define __va(x)			((void *)__phys_to_virt((phys_addr_t)(x)))
 #define pfn_to_kaddr(pfn)	__va((phys_addr_t)(pfn) << PAGE_SHIFT)