linux/usr/include/Makefile
Elliot Berman f67695c996 kbuild: Add environment variables for userprogs flags
Allow additional arguments be passed to userprogs compilation.
Reproducible clang builds need to provide a sysroot and gcc path to
ensure the same toolchain is used across hosts. KCFLAGS is not currently
used for any user programs compilation, so add new USERCFLAGS and
USERLDFLAGS which serves similar purpose as HOSTCFLAGS/HOSTLDFLAGS.

Clang 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@quicinc.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-02-14 10:37:32 +09:00

114 lines
3.6 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0-only
# Unlike the kernel space, exported headers are written in standard C.
# - Forbid C++ style comments
# - Use '__inline__', '__asm__' instead of 'inline', 'asm'
#
# -std=c90 (equivalent to -ansi) catches the violation of those.
# We cannot go as far as adding -Wpedantic since it emits too many warnings.
UAPI_CFLAGS := -std=c90 -Wall -Werror=implicit-function-declaration
# In theory, we do not care -m32 or -m64 for header compile tests.
# 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$(objtree)/usr/include
# The following are excluded for now because they fail to build.
#
# Do not add a new header to the blacklist without legitimate reason.
# Please consider to fix the header first.
#
# Sorted alphabetically.
no-header-test += asm/shmbuf.h
no-header-test += asm/signal.h
no-header-test += asm/ucontext.h
no-header-test += drm/vmwgfx_drm.h
no-header-test += linux/am437x-vpfe.h
no-header-test += linux/android/binder.h
no-header-test += linux/android/binderfs.h
no-header-test += linux/coda.h
no-header-test += linux/cyclades.h
no-header-test += linux/errqueue.h
no-header-test += linux/fsmap.h
no-header-test += linux/hdlc/ioctl.h
no-header-test += linux/ivtv.h
no-header-test += linux/kexec.h
no-header-test += linux/matroxfb.h
no-header-test += linux/omap3isp.h
no-header-test += linux/omapfb.h
no-header-test += linux/patchkey.h
no-header-test += linux/phonet.h
no-header-test += linux/reiserfs_xattr.h
no-header-test += linux/sctp.h
no-header-test += linux/signal.h
no-header-test += linux/sysctl.h
no-header-test += linux/usb/audio.h
no-header-test += linux/v4l2-mediabus.h
no-header-test += linux/v4l2-subdev.h
no-header-test += linux/videodev2.h
no-header-test += linux/vm_sockets.h
no-header-test += sound/asequencer.h
no-header-test += sound/asoc.h
no-header-test += sound/asound.h
no-header-test += sound/compress_offload.h
no-header-test += sound/emu10k1.h
no-header-test += sound/sfnt_info.h
no-header-test += xen/evtchn.h
no-header-test += xen/gntdev.h
no-header-test += xen/privcmd.h
# More headers are broken in some architectures
ifeq ($(SRCARCH),arc)
no-header-test += linux/bpf_perf_event.h
endif
ifeq ($(SRCARCH),ia64)
no-header-test += asm/setup.h
no-header-test += asm/sigcontext.h
no-header-test += linux/if_bonding.h
endif
ifeq ($(SRCARCH),mips)
no-header-test += asm/stat.h
endif
ifeq ($(SRCARCH),powerpc)
no-header-test += asm/stat.h
no-header-test += linux/bpf_perf_event.h
endif
ifeq ($(SRCARCH),riscv)
no-header-test += linux/bpf_perf_event.h
endif
ifeq ($(SRCARCH),sparc)
no-header-test += asm/stat.h
no-header-test += asm/uctx.h
no-header-test += asm/fbio.h
endif
# asm-generic/*.h is used by asm/*.h, and should not be included directly
no-header-test += asm-generic/%
extra-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/dev/null))
# Include the header twice to detect missing include guard.
quiet_cmd_hdrtest = HDRTEST $<
cmd_hdrtest = \
$(CC) $(c_flags) -S -o /dev/null -x c /dev/null \
$(if $(filter-out $(no-header-test), $*.h), -include $< -include $<); \
$(PERL) $(srctree)/$(src)/headers_check.pl $(obj) $(SRCARCH) $<; \
touch $@
$(obj)/%.hdrtest: $(obj)/%.h FORCE
$(call if_changed_dep,hdrtest)
# Since GNU Make 4.3, $(patsubst $(obj)/%/,%,$(wildcard $(obj)/*/)) works.
# To support older Make versions, use a somewhat tedious way.
clean-files += $(filter-out Makefile headers_check.pl, $(notdir $(wildcard $(obj)/*)))