From 0cd9ff8987f9d4f303e01aefe9bfc812916fee04 Mon Sep 17 00:00:00 2001
From: Martin Roth <martinroth@google.com>
Date: Mon, 1 Feb 2016 17:33:37 -0700
Subject: [PATCH] xcompile: Add a way to specify -march=i586

Instead of instructing users to edit xcompile when they want to build
a quark platform, give the build a way to set -march=586 so that
the quark code will build correctly.  The Quark processor does not
support the instructions introduced with the Pentium 6 architecture.

Change-Id: I0ed69aadc515f86f76800180e0e33bcd75feac5a
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/13552
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)
Reviewed-by: Leroy P Leahy <leroy.p.leahy@intel.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: FEI WANG <wangfei.jimei@gmail.com>
---
 src/arch/x86/Kconfig   |  6 ++++++
 util/xcompile/xcompile | 27 ++++++++++++++++++++++-----
 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/src/arch/x86/Kconfig b/src/arch/x86/Kconfig
index 738e7d1c0a..49f940acd1 100644
--- a/src/arch/x86/Kconfig
+++ b/src/arch/x86/Kconfig
@@ -58,6 +58,12 @@ config ARCH_RAMSTAGE_X86_64
 	bool
 	default n
 
+config USE_MARCH_586
+	def_bool n
+	help
+	  Allow a platform or processor to select to be compiled using
+	  the '-march=i586' option instead of the typical '-march=i686'
+
 # This is an SMP option. It relates to starting up APs.
 # It is usually set in mainboard/*/Kconfig.
 # TODO: Improve description.
diff --git a/util/xcompile/xcompile b/util/xcompile/xcompile
index 176518362f..79c8a4c0b0 100755
--- a/util/xcompile/xcompile
+++ b/util/xcompile/xcompile
@@ -182,11 +182,6 @@ detect_special_flags() {
 
 	case "$architecture" in
 	x86)
-		# Always build for i686 -- no sse/mmx instructions since SMM
-		# modules are compiled using these flags. Note that this
-		# doesn't prevent a project using xcompile to explicitly
-		# specify -mmsse, etc flags.
-		CFLAGS_GCC="$CFLAGS_GCC  -march=i686"
 		;;
 	x64)
 		;;
@@ -224,6 +219,27 @@ GCC_CC_${TARCH}:=${GCC}
 GCC_CFLAGS_${TARCH}:=${CFLAGS_GCC}
 GCC_COMPILER_RT_${TARCH}:=${CC_RT_GCC}
 GCC_COMPILER_RT_FLAGS_${TARCH}:=${CC_RT_EXTRA_GCC}
+EOF
+
+# Generally the x86 should build for i686 -- no sse/mmx
+# instructions since SMM modules are compiled using these
+# flags. Note that this doesn't prevent a project using
+# xcompile to explicitly specify -mmsse, etc flags.
+# The Quark processor doesn't support the instructions
+# introduced with the Pentium 6 architecture, so allow it
+# to use i586 instead.
+if [ "${TARCH}" = "x86_64" ] || [ "${TARCH}" = "x86_32" ]; then
+cat <<EOF
+
+ifeq (\$(CONFIG_USE_MARCH_586),y)
+	GCC_CFLAGS_${TARCH} += -march=i586
+else
+	GCC_CFLAGS_${TARCH} += -march=i686
+endif
+EOF
+fi
+
+cat <<EOF
 
 # Clang
 CLANG_CC_${TARCH}:=${CLANG}
@@ -245,6 +261,7 @@ else
 	COMPILER_RT_${TARCH}:=\$(CLANG_COMPILER_RT_${TARCH})
 	COMPILER_RT_FLAGS_${TARCH}:=\$(CLANG_COMPILER_RT_FLAGS_${TARCH})
 endif
+
 CPP_${TARCH}:=${GCCPREFIX}cpp
 AS_${TARCH}:=${GCCPREFIX}as ${ASFLAGS}
 LD_${TARCH}:=${GCCPREFIX}ld${LINKER_SUFFIX} ${LDFLAGS}