Hi Riku, On 04/11/15 10:02, Riku Voipio wrote: > On 30 October 2015 at 19:20, Andre Przywara <andre.przywara@xxxxxxx> wrote: >> When a Makefile variable is set on the make command line, all >> Makefile-internal assignments to that very variable are _ignored_. >> Since we add quite some essential values to CFLAGS internally, >> specifying some CFLAGS on the command line will usually break the >> build (and not fix any include file problems you hoped to overcome >> with that). >> Somewhat against intuition GNU make provides the "override" directive >> to change this behavior; with that assignments in the Makefile get >> _appended_ to the value given on the command line. [1] >> >> Change any internal assignments to use that directive, so that a user >> can use: >> $ make CFLAGS=/path/to/my/include/dir >> to teach kvmtool about non-standard header file locations (helpful >> for cross-compilation) or to tweak other compiler options. >> >> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx> >> >> [1] https://www.gnu.org/software/make/manual/html_node/Override-Directive.html >> --- >> Makefile | 15 +++++++-------- >> 1 file changed, 7 insertions(+), 8 deletions(-) >> >> diff --git a/Makefile b/Makefile >> index f8f7cc4..77a7c9f 100644 >> --- a/Makefile >> +++ b/Makefile >> @@ -15,9 +15,7 @@ include config/utilities.mak >> include config/feature-tests.mak >> >> CC := $(CROSS_COMPILE)gcc >> -CFLAGS := >> LD := $(CROSS_COMPILE)ld >> -LDFLAGS := > > This breaks builds of debian packages as dpkg-buildpackage sets LDFLAGS > to something unsuitable for guest init. > > Looks like this has been an issue before: > > commit 57fa349a9792a629e4ed2d89e1309cc96dcc39af > Author: Will Deacon <will.deacon@xxxxxxx> > Date: Thu Jun 4 16:25:36 2015 +0100 > > Don't inherit CFLAGS and LDFLAGS from the environment > > kvmtool doesn't build with arbitrary flags, so let's clear CFLAGS and > LDFLAGS by default at the top of the Makefile, allowing people to add > additional options there if they really want to. > > Reported by Dave Jones, who ended up passing -std=gnu99 by mistake. Well, I fixed this issue later with making kvmtool compilation more robust when using modern compiler standards. That's why I wanted this kludge to go away. > I think it's better to have EXTRA_CFLAGS and EXTRA_LDFLAGS like the kernel > has. Mmmh, I'd rather see guest_init creation use their own flags for it, since it is so special and actually independent from the target userland. Let me check this out and send out my guest_init Makefile fix I have lying around here on the way. What LDFLAGS are actually causing your issues? Cheers, Andre. > >> FIND := find >> CSCOPE := cscope >> @@ -162,7 +160,7 @@ ifeq ($(ARCH), arm) >> OBJS += arm/aarch32/kvm-cpu.o >> ARCH_INCLUDE := $(HDRS_ARM_COMMON) >> ARCH_INCLUDE += -Iarm/aarch32/include >> - CFLAGS += -march=armv7-a >> + override CFLAGS += -march=armv7-a >> >> ARCH_WANT_LIBFDT := y >> endif >> @@ -274,12 +272,12 @@ endif >> ifeq ($(LTO),1) >> FLAGS_LTO := -flto >> ifeq ($(call try-build,$(SOURCE_HELLO),$(CFLAGS),$(FLAGS_LTO)),y) >> - CFLAGS += $(FLAGS_LTO) >> + override CFLAGS += $(FLAGS_LTO) >> endif >> endif >> >> ifeq ($(call try-build,$(SOURCE_STATIC),,-static),y) >> - CFLAGS += -DCONFIG_GUEST_INIT >> + override CFLAGS += -DCONFIG_GUEST_INIT >> GUEST_INIT := guest/init >> GUEST_OBJS = guest/guest_init.o >> ifeq ($(ARCH_PRE_INIT),) >> @@ -331,7 +329,8 @@ DEFINES += -DKVMTOOLS_VERSION='"$(KVMTOOLS_VERSION)"' >> DEFINES += -DBUILD_ARCH='"$(ARCH)"' >> >> KVM_INCLUDE := include >> -CFLAGS += $(CPPFLAGS) $(DEFINES) -I$(KVM_INCLUDE) -I$(ARCH_INCLUDE) -O2 -fno-strict-aliasing -g >> +override CFLAGS += $(CPPFLAGS) $(DEFINES) -I$(KVM_INCLUDE) -I$(ARCH_INCLUDE) >> +override CFLAGS += -O2 -fno-strict-aliasing -g >> >> WARNINGS += -Wall >> WARNINGS += -Wformat=2 >> @@ -349,10 +348,10 @@ WARNINGS += -Wvolatile-register-var >> WARNINGS += -Wwrite-strings >> WARNINGS += -Wno-format-nonliteral >> >> -CFLAGS += $(WARNINGS) >> +override CFLAGS += $(WARNINGS) >> >> ifneq ($(WERROR),0) >> - CFLAGS += -Werror >> + override CFLAGS += -Werror >> endif >> >> all: $(PROGRAM) $(PROGRAM_ALIAS) $(GUEST_INIT) $(GUEST_PRE_INIT) >> -- >> 2.5.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe kvm" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
