[POWERPC] Make instruction dumping work in real mode

On non-book-E, exceptions execute in real mode.  If a fault happens
that leads to a register dump, the kernel currently prints XXXXXXXX
because it doesn't realize that PC is a physical address.

This patch checks whether instruction address translation is turned
on, and if not converts PC into a virtual address.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/process.c

@@ -354,6 +354,14 @@ static void show_instructions(struct pt_regs *regs)
 		if (!(i % 8))
 			printk("\n");
 
+#if !defined(CONFIG_BOOKE)
+		/* If executing with the IMMU off, adjust pc rather
+		 * than print XXXXXXXX.
+		 */
+		if (!(regs->msr & MSR_IR))
+			pc = (unsigned long)phys_to_virt(pc);
+#endif
+
 		/* We use __get_user here *only* to avoid an OOPS on a
 		 * bad address because the pc *should* only be a
 		 * kernel address.