From: Max Filippov <jcmvbkbc@gmail.com>
Date: Fri, 28 Apr 2017 16:40:00 +0000 (-0700)
Subject: xtensa: add -mno-serialize-volatile to CFLAGS
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7bf5234db7cce45fa9ff237ce0f45da2bd277cad;p=linux.git

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 7ee02fe4a63df..a206598b5d95c 100644
--- a/arch/xtensa/Makefile
+++ b/arch/xtensa/Makefile
@@ -46,6 +46,7 @@ KBUILD_CFLAGS += -ffreestanding -D__linux__
 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