opensbi: Use -ffreestanding compiler options

This usually helps compiler to not use built-in optimizations
for string functions and mem* functions unnecessarily, since OE's
compiler is hosted for linux cross compile, this also means we instruct
it rightly for building a baremetal application

Refresh the patches to apply without fuzz
Fixes linking errors e.g.

platform/qemu/virt/lib/libplatsbi.a(sbi_string.o): in function `sbi_memset':
| /mnt/b/yoe/build/tmp/work/riscv64-yoe-linux/opensbi/0.5-r0/git/lib/sbi/sbi_string.c:102: undefined reference to `memset'
| collect2: error: ld returned 1 exit status

Signed-off-by: Khem Raj <[email protected]>
Signed-off-by: Richard Purdie <[email protected]>

meta/recipes-bsp/opensbi/files/0001-Makefile-Don-t-specify-mabi-or-march.patch

@@ -13,26 +13,21 @@ Signed-off-by: Alistair Francis <[email protected]>
  Makefile | 2 --
  1 file changed, 2 deletions(-)
 
-diff --git a/Makefile b/Makefile
-index ae68f55..10851fc 100644
 --- a/Makefile
 +++ b/Makefile
-@@ -145,7 +145,6 @@ GENFLAGS	+=	$(firmware-genflags-y)
+@@ -162,7 +162,6 @@ GENFLAGS	+=	$(firmware-genflags-y)
  CFLAGS		=	-g -Wall -Werror -nostdlib -fno-strict-aliasing -O2
  CFLAGS		+=	-fno-omit-frame-pointer -fno-optimize-sibling-calls
  CFLAGS		+=	-mno-save-restore -mstrict-align
 -CFLAGS		+=	-mabi=$(PLATFORM_RISCV_ABI) -march=$(PLATFORM_RISCV_ISA)
  CFLAGS		+=	-mcmodel=$(PLATFORM_RISCV_CODE_MODEL)
  CFLAGS		+=	$(GENFLAGS)
  CFLAGS		+=	$(platform-cflags-y)
-@@ -158,7 +157,6 @@ CPPFLAGS	+=	$(firmware-cppflags-y)
+@@ -176,7 +175,6 @@ CPPFLAGS	+=	$(firmware-cppflags-y)
  ASFLAGS		=	-g -Wall -nostdlib -D__ASSEMBLY__
  ASFLAGS		+=	-fno-omit-frame-pointer -fno-optimize-sibling-calls
  ASFLAGS		+=	-mno-save-restore -mstrict-align
 -ASFLAGS		+=	-mabi=$(PLATFORM_RISCV_ABI) -march=$(PLATFORM_RISCV_ISA)
  ASFLAGS		+=	-mcmodel=$(PLATFORM_RISCV_CODE_MODEL)
  ASFLAGS		+=	$(GENFLAGS)
  ASFLAGS		+=	$(platform-asflags-y)
--- 
-2.20.1
-

meta/recipes-bsp/opensbi/files/0001-build-Use-ffreestanding.patch

@@ -0,0 +1,28 @@
+From efa39afecedf75a1f3154c39507bdde2810bc140 Mon Sep 17 00:00:00 2001
+From: Khem Raj <[email protected]>
+Date: Mon, 6 Jan 2020 18:21:02 -0800
+Subject: [PATCH] build: Use -ffreestanding
+
+this is a stand-alone/baremetal application, therefore demanding
+-ffreestanding would help it compile with hosted toolchains e.g. ( linux
+toolchains ), it also ensures that it won't be using platform
+optimizations like inlining mem* str* functions which gcc might decide
+especially with wrapper string functions in opensbi code
+
+Upstream-Status: Accepted [https://github.com/riscv/opensbi/commit/049ad0b3877352527ab470eba33bc767e9b54961]
+Signed-off-by: Khem Raj <[email protected]>
+---
+ Makefile | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/Makefile
++++ b/Makefile
+@@ -159,7 +159,7 @@ GENFLAGS	+=	$(libsbiutils-genflags-y)
+ GENFLAGS	+=	$(platform-genflags-y)
+ GENFLAGS	+=	$(firmware-genflags-y)
+
+-CFLAGS		=	-g -Wall -Werror -nostdlib -fno-strict-aliasing -O2
++CFLAGS		=	-g -Wall -Werror -ffreestanding -nostdlib -fno-strict-aliasing -O2
+ CFLAGS		+=	-fno-omit-frame-pointer -fno-optimize-sibling-calls
+ CFLAGS		+=	-mno-save-restore -mstrict-align
+ CFLAGS		+=	-mcmodel=$(PLATFORM_RISCV_CODE_MODEL)

meta/recipes-bsp/opensbi/opensbi_0.5.bb

@@ -11,6 +11,7 @@ inherit autotools-brokensep deploy
 SRCREV = "be92da280d87c38a2e0adc5d3f43bab7b5468f09"
 SRC_URI = "git://github.com/riscv/opensbi.git \
            file://0001-Makefile-Don-t-specify-mabi-or-march.patch \
+           file://0001-build-Use-ffreestanding.patch \
           "
 
 S = "${WORKDIR}/git"