[LTP] [PATCH] Add KVM_LD Makefile variable for building KVM payload binaries

[Martin Doucha]

KVM linker needs to be configurable for cross-compiling but some
linkers don't support the linker script for wrapping arbitrary files
into linkable resource files. Allow KVM linker to be changed
independently of $LD via $KVM_LD.

Signed-off-by: Martin Doucha <mdoucha@suse.cz>
---

This should solve the issues with
https://github.com/linux-test-project/ltp/pull/948

 doc/build-system-guide.txt    | 5 +++++
 testcases/kernel/kvm/Makefile | 5 +++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/doc/build-system-guide.txt b/doc/build-system-guide.txt
index 166f7fb92..b8d267b4b 100644
--- a/doc/build-system-guide.txt
+++ b/doc/build-system-guide.txt
@@ -145,6 +145,11 @@ $(CPPFLAGS)		: Preprocessor flags, e.g. -I arguments.
 
 $(DEBUG_CFLAGS)		: Debug flags to pass to $(CC), -g, etc.
 
+$(KVM_LD)		: Special linker for wrapping KVM payload binaries
+			  into linkable object files. Defaults to $(LD).
+			  Change this variable if the KVM Makefile fails
+			  to build files named *-payload.o.
+
 $(LD)			: The system linker (typically $(CC), but not
 			  necessarily).
 
diff --git a/testcases/kernel/kvm/Makefile b/testcases/kernel/kvm/Makefile
index 22a840da6..6986844be 100644
--- a/testcases/kernel/kvm/Makefile
+++ b/testcases/kernel/kvm/Makefile
@@ -11,6 +11,7 @@ GUEST_CPPFLAGS = $(CPPFLAGS) -DCOMPILE_PAYLOAD
 GUEST_CFLAGS = -ffreestanding -O2 -Wall -fno-asynchronous-unwind-tables -mno-mmx -mno-sse
 GUEST_LDFLAGS = -nostdlib -Wl,--build-id=none -fno-stack-protector
 GUEST_LDLIBS =
+KVM_LD ?= $(LD)
 
 FILTER_OUT_MAKE_TARGETS := lib_guest lib_host lib_x86
 
@@ -53,11 +54,11 @@ include $(top_srcdir)/include/mk/generic_leaf_target.mk
 ifdef VERBOSE
 	$(CC) $(GUEST_CPPFLAGS) $(GUEST_CFLAGS) $(GUEST_LDFLAGS) -o $*-payload.elf $^ $(GUEST_LDLIBS)
 	objcopy -O binary -j .init.boot -j .text -j .data -j .init -j .preinit_array -j .init_array --gap-fill=0 $*-payload.elf $*-payload.bin
-	$(LD) -z noexecstack -r -T $(abs_srcdir)/linker/payload.lds --oformat=$(BIN_FORMAT) -o $@ $*-payload.bin
+	$(KVM_LD) -z noexecstack -r -T $(abs_srcdir)/linker/payload.lds --oformat=$(BIN_FORMAT) -o $@ $*-payload.bin
 else
 	@$(CC) $(GUEST_CPPFLAGS) $(GUEST_CFLAGS) $(GUEST_LDFLAGS) -o $*-payload.elf $^ $(GUEST_LDLIBS)
 	@objcopy -O binary -j .init.boot -j .text -j .data -j .init -j .preinit_array -j .init_array --gap-fill=0 $*-payload.elf $*-payload.bin
-	@$(LD) -z noexecstack -r -T $(abs_srcdir)/linker/payload.lds --oformat=$(BIN_FORMAT) -o $@ $*-payload.bin
+	@$(KVM_LD) -z noexecstack -r -T $(abs_srcdir)/linker/payload.lds --oformat=$(BIN_FORMAT) -o $@ $*-payload.bin
 	@echo KVM_CC $(target_rel_dir)$@
 endif
 	@rm $*-payload.elf $*-payload.bin
-- 
2.36.1