xtensa: add -mno-serialize-volatile to CFLAGS
By default xtensa gcc inserts memw for all volatile object accesses.
This is too pessimistic for the kernel: there should be no "normal"
volatile objects, and all special objects, like MMIO or objects shared
between CPUs should have explicit barriers.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
diff --git a/arch/xtensa/Makefile b/arch/xtensa/Makefile
index 7ee02fe..a206598 100644
--- a/arch/xtensa/Makefile
+++ b/arch/xtensa/Makefile
@@ -46,6 +46,7 @@
KBUILD_CFLAGS += -pipe -mlongcalls
KBUILD_CFLAGS += $(call cc-option,-mforce-no-pic,)
+KBUILD_CFLAGS += $(call cc-option,-mno-serialize-volatile,)
ifneq ($(CONFIG_LD_NO_RELAX),)
LDFLAGS := --no-relax