1# SPDX-License-Identifier: GPL-2.0-only
  2
  3# Unlike the kernel space, exported headers are written in standard C.
  4#  - Forbid C++ style comments
  5#  - Use '__inline__', '__asm__' instead of 'inline', 'asm'
  6#
  7# -std=c90 (equivalent to -ansi) catches the violation of those.
  8# We cannot go as far as adding -Wpedantic since it emits too many warnings.
  9UAPI_CFLAGS := -std=c90 -Wall -Werror=implicit-function-declaration
 10
 11# In theory, we do not care -m32 or -m64 for header compile tests.
 12# It is here just because CONFIG_CC_CAN_LINK is tested with -m32 or -m64.
 13UAPI_CFLAGS += $(filter -m32 -m64, $(KBUILD_CFLAGS))
 14
 15override c_flags = $(UAPI_CFLAGS) -Wp,-MMD,$(depfile) -I$(objtree)/usr/include
 16
 17# The following are excluded for now because they fail to build.
 18#
 19# Do not add a new header to the blacklist without legitimate reason.
 20# Please consider to fix the header first.
 21#
 22# Sorted alphabetically.
 23no-header-test += asm/shmbuf.h
 24no-header-test += asm/signal.h
 25no-header-test += asm/ucontext.h
 26no-header-test += drm/vmwgfx_drm.h
 27no-header-test += linux/am437x-vpfe.h
 28no-header-test += linux/android/binder.h
 29no-header-test += linux/android/binderfs.h
 30no-header-test += linux/coda.h
 31no-header-test += linux/errqueue.h
 32no-header-test += linux/fsmap.h
 33no-header-test += linux/hdlc/ioctl.h
 34no-header-test += linux/ivtv.h
 35no-header-test += linux/kexec.h
 36no-header-test += linux/matroxfb.h
 37no-header-test += linux/nfc.h
 38no-header-test += linux/omap3isp.h
 39no-header-test += linux/omapfb.h
 40no-header-test += linux/patchkey.h
 41no-header-test += linux/phonet.h
 42no-header-test += linux/reiserfs_xattr.h
 43no-header-test += linux/sctp.h
 44no-header-test += linux/signal.h
 45no-header-test += linux/sysctl.h
 46no-header-test += linux/usb/audio.h
 47no-header-test += linux/v4l2-mediabus.h
 48no-header-test += linux/v4l2-subdev.h
 49no-header-test += linux/videodev2.h
 50no-header-test += linux/vm_sockets.h
 51no-header-test += sound/asequencer.h
 52no-header-test += sound/asoc.h
 53no-header-test += sound/asound.h
 54no-header-test += sound/compress_offload.h
 55no-header-test += sound/emu10k1.h
 56no-header-test += sound/sfnt_info.h
 57no-header-test += xen/evtchn.h
 58no-header-test += xen/gntdev.h
 59no-header-test += xen/privcmd.h
 60
 61# More headers are broken in some architectures
 62
 63ifeq ($(SRCARCH),arc)
 64no-header-test += linux/bpf_perf_event.h
 65endif
 66
 67ifeq ($(SRCARCH),ia64)
 68no-header-test += asm/setup.h
 69no-header-test += asm/sigcontext.h
 70no-header-test += linux/if_bonding.h
 71endif
 72
 73ifeq ($(SRCARCH),mips)
 74no-header-test += asm/stat.h
 75endif
 76
 77ifeq ($(SRCARCH),powerpc)
 78no-header-test += asm/stat.h
 79no-header-test += linux/bpf_perf_event.h
 80endif
 81
 82ifeq ($(SRCARCH),riscv)
 83no-header-test += linux/bpf_perf_event.h
 84endif
 85
 86ifeq ($(SRCARCH),sparc)
 87no-header-test += asm/stat.h
 88no-header-test += asm/uctx.h
 89no-header-test += asm/fbio.h
 90endif
 91
 92# asm-generic/*.h is used by asm/*.h, and should not be included directly
 93no-header-test += asm-generic/%
 94
 95extra-y := $(patsubst $(obj)/%.h,%.hdrtest, $(shell find $(obj) -name '*.h' 2>/dev/null))
 96
 97# Include the header twice to detect missing include guard.
 98quiet_cmd_hdrtest = HDRTEST $<
 99      cmd_hdrtest = \
100		$(CC) $(c_flags) -S -o /dev/null -x c /dev/null \
101			$(if $(filter-out $(no-header-test), $*.h), -include $< -include $<); \
102		$(PERL) $(srctree)/scripts/headers_check.pl $(obj) $(SRCARCH) $<; \
103		touch $@
104
105$(obj)/%.hdrtest: $(obj)/%.h FORCE
106	$(call if_changed_dep,hdrtest)
107
108clean-files += $(filter-out Makefile, $(notdir $(wildcard $(obj)/*)))