UBUNTU: SAUCE: rfi-flush: Expand the RFI section to two nop slots

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

@@ -58,10 +58,12 @@
  */
 #define PREPARE_RFI_TO_USER						\
 	RFI_FLUSH_FIXUP_SECTION;					\
+	nop;								\
 	nop
 
 #define PREPARE_RFI_TO_GUEST						\
 	RFI_FLUSH_FIXUP_SECTION;					\
+	nop;								\
 	nop
 
 #ifdef CONFIG_PPC_DEBUG_RFI

arch/powerpc/lib/feature-fixups.c

@@ -142,7 +142,8 @@ void do_rfi_flush_fixups(enum l1d_flush_type types)
 		dest = (void *)start + *start;
 
 		pr_devel("patching dest %lx\n", (unsigned long)dest);
-		patch_instruction(dest, instr);
+		patch_instruction(dest, 0x60000000);
+		patch_instruction(dest + 1, instr);
 	}
 
 	printk(KERN_DEBUG "rfi-fixups: patched %d locations\n", i);