On Tue, Feb 1, 2022 at 1:36 PM Elliot Berman <quic_eberman@xxxxxxxxxxx> wrote: > > Allow additional arguments be passed to userprogs compilation. > Reproducible clang builds need to provide a sysroot and gcc path to > ensure same toolchain is used across hosts. KCFLAGS is not currently ^ ensure the same (maybe Masahiro can fix that up locally when applying) > used for any user programs compilation, so add new USERCFLAGS and > USERLDFLAGS which serves similar purpose as HOSTCFLAGS/HOSTLDFLAGS. > > Clang 13+ might detect GCC installation on hosts which have it installed > to a default location in /. With addition of these environment > variables, you can specify flags such as: > > $ make USERCFLAGS=--sysroot=/path/to/sysroot > > This can also be used to specify different sysroots such as musl or > bionic which may be installed on the host in paths that the compiler > may not search by default. > > Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx> Thanks for the patch! Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- > > Changes since v2: > - Incorporated Nick's suggestions: > - Addressed docs and commit text comments > - Introduced KBUILD_USERHOSTCFLAGS as suggested > > Documentation/kbuild/kbuild.rst | 11 +++++++++++ > Documentation/kbuild/makefiles.rst | 2 ++ > Makefile | 10 ++++++---- > init/Kconfig | 8 ++++---- > usr/include/Makefile | 3 +++ > 5 files changed, 26 insertions(+), 8 deletions(-) > > diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst > index 2d1fc03d346e..ef19b9c13523 100644 > --- a/Documentation/kbuild/kbuild.rst > +++ b/Documentation/kbuild/kbuild.rst > @@ -77,6 +77,17 @@ HOSTLDLIBS > ---------- > Additional libraries to link against when building host programs. > > +.. _userkbuildflags: > + > +USERCFLAGS > +---------- > +Additional options used for $(CC) when compiling userprogs. > + > +USERLDFLAGS > +----------- > +Additional options used for $(LD) when linking userprogs. userprogs are linked > +with CC, so $(USERLDFLAGS) should include "-Wl," prefix as applicable. > + > KBUILD_KCONFIG > -------------- > Set the top-level Kconfig file to the value of this environment > diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst > index b008b90b92c9..11a296e52d68 100644 > --- a/Documentation/kbuild/makefiles.rst > +++ b/Documentation/kbuild/makefiles.rst > @@ -982,6 +982,8 @@ The syntax is quite similar. The difference is to use "userprogs" instead of > > When linking bpfilter_umh, it will be passed the extra option -static. > > + From command line, :ref:`USERCFLAGS and USERLDFLAGS <userkbuildflags>` will also be used. > + > 5.4 When userspace programs are actually built > ---------------------------------------------- > > diff --git a/Makefile b/Makefile > index 45278d508d81..1d0172449355 100644 > --- a/Makefile > +++ b/Makefile > @@ -431,11 +431,12 @@ HOSTCC = gcc > HOSTCXX = g++ > endif > > -export KBUILD_USERCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ > - -O2 -fomit-frame-pointer -std=gnu89 > -export KBUILD_USERLDFLAGS := > +KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \ > + -O2 -fomit-frame-pointer -std=gnu89 > +KBUILD_USERCFLAGS := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS) > +KBUILD_USERLDFLAGS := $(USERLDFLAGS) > > -KBUILD_HOSTCFLAGS := $(KBUILD_USERCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS) > +KBUILD_HOSTCFLAGS := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS) > KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS) > KBUILD_HOSTLDFLAGS := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS) > KBUILD_HOSTLDLIBS := $(HOST_LFS_LIBS) $(HOSTLDLIBS) > @@ -530,6 +531,7 @@ export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AW > export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX > export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD > export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE > +export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS > > export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS > export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE > diff --git a/init/Kconfig b/init/Kconfig > index f2ae41e6717f..164706c38e8b 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -62,13 +62,13 @@ config LLD_VERSION > > config CC_CAN_LINK > bool > - default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag)) if 64BIT > - default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag)) > + default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag)) if 64BIT > + default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag)) > > config CC_CAN_LINK_STATIC > bool > - default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m64-flag) -static) if 64BIT > - default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(m32-flag) -static) > + default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m64-flag) -static) if 64BIT > + default $(success,$(srctree)/scripts/cc-can-link.sh $(CC) $(CLANG_FLAGS) $(USERCFLAGS) $(USERLDFLAGS) $(m32-flag) -static) > > config CC_HAS_ASM_GOTO > def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC)) > diff --git a/usr/include/Makefile b/usr/include/Makefile > index 1c2ae1368079..0322e567dc1e 100644 > --- a/usr/include/Makefile > +++ b/usr/include/Makefile > @@ -12,6 +12,9 @@ UAPI_CFLAGS := -std=c90 -Wall -Werror=implicit-function-declaration > # It is here just because CONFIG_CC_CAN_LINK is tested with -m32 or -m64. > UAPI_CFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS)) > > +# USERCFLAGS might contain sysroot location for CC. > +UAPI_CFLAGS += $(USERCFLAGS) > + > override c_flags = $(UAPI_CFLAGS) -Wp,-MMD,$(depfile) -I$(objtree)/usr/include > > # The following are excluded for now because they fail to build. > -- > 2.25.1 > -- Thanks, ~Nick Desaulniers
