On 4 November 2015 at 12:13, Andre Przywara <andre.przywara@xxxxxxx> wrote: > 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 := $(CROSS_COMPILE)ld >>> -LDFLAGS := >> >> This breaks builds of debian packages as dpkg-buildpackage sets LDFLAGS >> to something unsuitable for guest init. >> >> Looks like this has been an issue before: > >> >> commit 57fa349a9792a629e4ed2d89e1309cc96dcc39af >> Author: Will Deacon <will.deacon@xxxxxxx> >> Date: Thu Jun 4 16:25:36 2015 +0100 >> >> Don't inherit CFLAGS and LDFLAGS from the environment >> >> kvmtool doesn't build with arbitrary flags, so let's clear CFLAGS and >> LDFLAGS by default at the top of the Makefile, allowing people to add >> additional options there if they really want to. >> >> Reported by Dave Jones, who ended up passing -std=gnu99 by mistake. > > Well, I fixed this issue later with making kvmtool compilation more > robust when using modern compiler standards. > That's why I wanted this kludge to go away. > >> I think it's better to have EXTRA_CFLAGS and EXTRA_LDFLAGS like the kernel >> has. > > Mmmh, I'd rather see guest_init creation use their own flags for it, > since it is so special and actually independent from the target userland. > Let me check this out and send out my guest_init Makefile fix I have > lying around here on the way. > > What LDFLAGS are actually causing your issues? LINK guest/init ld: unrecognized option '-Wl,-z,relro' That's another issue - kvmtool passes LDFLAGS to both LD and CC yet they actually take different command line options. > Cheers, > Andre. > >> >>> FIND := find >>> CSCOPE := cscope >>> @@ -162,7 +160,7 @@ ifeq ($(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
