Toolchain: Fix QEMU build with latest gcc by disabling -fcf-protection

I noticed after upgrading my machine that the QEMU is no longer building
due to GCC enabling `-fcf-protection` by default, even for targets that
don't support it.

The included patch came from the QEMU development list, but hasn't be
included in any patch releases at the time of writing.
https://lore.kernel.org/all/20220208211937.79580-1-vineetg@rivosinc.com/

Until QEMU patches, lets fix it on our end by patching before we build.
This commit is contained in:
Brian Gianforcaro 2022-02-12 07:07:31 -08:00 committed by Brian Gianforcaro
parent b760a1a4ba
commit d386d3946a
2 changed files with 43 additions and 0 deletions

View file

@ -40,6 +40,12 @@ pushd "$DIR/Tarballs"
else
echo "Skipped extracting qemu"
fi
pushd "$QEMU_VERSION"
patch -p1 < "$DIR/Patches/qemu-cf-protection-none.patch" > /dev/null
md5sum "$DIR/Patches/qemu-cf-protection-none.patch" > .patch.applied
popd
popd
mkdir -p "$PREFIX"

View file

@ -0,0 +1,37 @@
Subject: [PATCH] build: fix build failure with gcc 11.2 by disabling -fcf-protection
Date: Tue, 8 Feb 2022 13:19:37 -0800 [thread overview]
Message-ID: <20220208211937.79580-1-vineetg@rivosinc.com> (raw)
When doing RV qemu builds with host gcc 11.2, ran into following build failure
| cc -MMD -MP -MT linuxboot_dma.o -MF ./linuxboot_dma.d -O2 -g -march=i486 -Wall \
| -Wstrict-prototypes -Wredundant-decls -Wundef -Wwrite-strings -Wmissing-prototypes \
| -Wold-style-declaration -Wold-style-definition -Wtype-limits -Wformat-security \
| -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs \
| -Wendif-labels -Wexpansion-to-defined -Wimplicit-fallthrough=2 -Wno-missing-include-dirs \
| -Wno-shift-negative-value -Wno-psabi -fno-pie -ffreestanding -IQEMU/include \
| -fno-stack-protector -m16 -Wa,-32 \
| -c QEMU/pc-bios/optionrom/linuxboot_dma.c -o linuxboot_dma.o
|cc1: error: -fcf-protection is not compatible with this target
Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>
---
This might be a crude fix to the problem
---
pc-bios/optionrom/Makefile | 3 +++
1 file changed, 3 insertions(+)
diff --git a/pc-bios/optionrom/Makefile b/pc-bios/optionrom/Makefile
index 5d55d25acca2..8f843ee803c1 100644
--- a/pc-bios/optionrom/Makefile
+++ b/pc-bios/optionrom/Makefile
@@ -22,6 +22,9 @@ override CFLAGS += $(CFLAGS_NOPIE) -ffreestanding -I$(TOPSRC_DIR)/include
override CFLAGS += $(call cc-option, -fno-stack-protector)
override CFLAGS += $(call cc-option, -m16)
+# issue with gcc 11.2
+override CFLAGS += $(call cc-option, -fcf-protection=none)
+
ifeq ($(filter -m16, $(CFLAGS)),)
# Attempt to work around compilers that lack -m16 (GCC <= 4.8, clang <= ??)
# On GCC we add -fno-toplevel-reorder to keep the order of asm blocks with