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>

1 files changed, 19 insertions, 0 deletions

diff --git a/arch/arm/mm/pabort-legacy.S b/arch/arm/mm/pabort-legacy.S
new file mode 100644
index 000000000000..87970eba88ea
--- /dev/null
+++ b/arch/arm/mm/pabort-legacy.S
@@ -0,0 +1,19 @@
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Function: legacy_pabort
+ *
+ * Params  : r0 = address of aborted instruction
+ *
+ * Returns : r0 = address of abort
+ *         : r1 = Simulated IFSR with section translation fault status
+ *
+ * Purpose : obtain information about current prefetch abort.
+ */
+
+        .align  5
+ENTRY(legacy_pabort)
+        mov     r1, #5
+        mov     pc, lr
+ENDPROC(legacy_pabort)