powerpc: Handle exceptions caused by pkey violation

Handle Data and  Instruction exceptions caused by memory
protection-key.

The CPU will detect the key fault if the HPTE is already
programmed with the key.

However if the HPTE is not  hashed, a key fault will not
be detected by the hardware. The software will detect
pkey violation in such a case.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/exceptions-64s.S

@@ -1527,7 +1527,7 @@ USE_TEXT_SECTION()
 	.balign	IFETCH_ALIGN_BYTES
 do_hash_page:
 #ifdef CONFIG_PPC_BOOK3S_64
-	lis	r0,(DSISR_BAD_FAULT_64S|DSISR_DABRMATCH)@h
+	lis	r0,(DSISR_BAD_FAULT_64S | DSISR_DABRMATCH | DSISR_KEYFAULT)@h
 	ori	r0,r0,DSISR_BAD_FAULT_64S@l
 	and.	r0,r4,r0		/* weird error? */
 	bne-	handle_page_fault	/* if not, try to insert a HPTE */