mips: Enable KCSAN

This patch enables KCSAN for the 64-bit version. Updated rules
for the incompatible compilation units (vdso, boot/compressed).

Signed-off-by: Nemanja Rakovic <nemanja.rakovic@syrmia.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/Kconfig

@@ -101,6 +101,7 @@ config MIPS
 	select TRACE_IRQFLAGS_SUPPORT
 	select VIRT_TO_BUS
 	select ARCH_HAS_ELFCORE_COMPAT
+	select HAVE_ARCH_KCSAN if 64BIT
 
 config MIPS_FIXUP_BIGPHYS_ADDR
 	bool

arch/mips/boot/compressed/Makefile

@@ -38,6 +38,7 @@ KBUILD_AFLAGS := $(KBUILD_AFLAGS) -D__ASSEMBLY__ \
 KCOV_INSTRUMENT		:= n
 GCOV_PROFILE := n
 UBSAN_SANITIZE := n
+KASAN_SANITIZE			:= n
 
 # decompressor objects (linked with vmlinuz)
 vmlinuzobjs-y := $(obj)/head.o $(obj)/decompress.o $(obj)/string.o $(obj)/bswapsi.o

arch/mips/vdso/Makefile

@@ -1,6 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0
 # Objects to go into the VDSO.
 
+# Sanitizer runtimes are unavailable and cannot be linked here.
+ KCSAN_SANITIZE			:= n
+
 # Absolute relocation type $(ARCH_REL_TYPE_ABS) needs to be defined before
 # the inclusion of generic Makefile.
 ARCH_REL_TYPE_ABS := R_MIPS_JUMP_SLOT|R_MIPS_GLOB_DAT