ARM: 5727/1: Pass IFSR register to do_PrefetchAbort()

Instruction fault status register, IFSR, was introduced on ARMv6 to
provide status information about the last insturction fault. It
needed for proper prefetch abort handling.

Now we have three prefetch abort model:

  * legacy - for CPUs before ARMv6. They doesn't provide neither
    IFSR nor IFAR. We simulate IFSR with section translation fault
    status for them to generalize code;
  * ARMv6 - provides IFSR, but not IFAR;
  * ARMv7 - provides both IFSR and IFAR.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/pabort-v7.S

@@ -0,0 +1,20 @@
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Function: v6_pabort
+ *
+ * Params  : r0 = address of aborted instruction
+ *
+ * Returns : r0 = address of abort
+ *	   : r1 = IFSR
+ *
+ * Purpose : obtain information about current prefetch abort.
+ */
+
+	.align	5
+ENTRY(v7_pabort)
+	mrc	p15, 0, r0, c6, c0, 2		@ get IFAR
+	mrc	p15, 0, r1, c5, c0, 1		@ get IFSR
+	mov	pc, lr
+ENDPROC(v7_pabort)