UBUNTU: SAUCE: rfi-flush: Add HRFI_TO_UNKNOWN and use it in denorm

CVE-2017-5754

BugLink: http://bugs.launchpad.net/bugs/1742772Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>

arch/powerpc/include/asm/exception-64s.h

@@ -116,6 +116,12 @@
 	hrfid;								\
 	b	hrfi_flush_fallback
 
+#define HRFI_TO_UNKNOWN							\
+	RFI_FLUSH_FIXUP_SECTION;					\
+	nop;								\
+	hrfid;								\
+	b	hrfi_flush_fallback
+
 #ifdef CONFIG_RELOCATABLE
 #define __EXCEPTION_RELON_PROLOG_PSERIES_1(label, h)			\
 	ld	r12,PACAKBASE(r13);	/* get high part of &label */	\

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

@@ -601,7 +601,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
 	ld	r11,PACA_EXGEN+EX_R11(r13)
 	ld	r12,PACA_EXGEN+EX_R12(r13)
 	ld	r13,PACA_EXGEN+EX_R13(r13)
-	HRFID
+	HRFI_TO_UNKNOWN
 	b	.
 #endif