powerpc/64e/interrupt: handle bad_page_fault in C

With non-volatile registers saved on interrupt, bad_page_fault
can now be called by do_page_fault.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-9-npiggin@gmail.com

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

@@ -937,12 +937,6 @@ storage_fault_common:
 	ld	r14,PACA_EXGEN+EX_R14(r13)
 	ld	r15,PACA_EXGEN+EX_R15(r13)
 	bl	do_page_fault
-	cmpdi	r3,0
-	bne-	1f
-	b	interrupt_return
-	mr	r4,r3
-	addi	r3,r1,STACK_FRAME_OVERHEAD
-	bl	__bad_page_fault
 	b	interrupt_return
 
 /*

arch/powerpc/mm/fault.c

@@ -552,12 +552,9 @@ static long __do_page_fault(struct pt_regs *regs)
 	if (likely(entry)) {
 		instruction_pointer_set(regs, extable_fixup(entry));
 		return 0;
-	} else if (!IS_ENABLED(CONFIG_PPC_BOOK3E_64)) {
+	} else {
 		__bad_page_fault(regs, err);
 		return 0;
-	} else {
-		/* 32 and 64e handle the bad page fault in asm */
-		return err;
 	}
 }
 NOKPROBE_SYMBOL(__do_page_fault);