Multiple people have suggested compile-testing UAPI headers to ensure they can be really included from user-space. "make headers_check" is obviously not enough to catch bugs, and we often leak unresolved references to user-space. Use the new header-test-y syntax to implement it. Please note exported headers are compile-tested with a completely different set of compiler flags. The header search path is set to $(objtree)/usr/include since exported headers should not include unexported ones. We use -std=gnu89 for the kernel space since the kernel code highly depends on GNU extensions. On the other hand, UAPI headers should be written in more standardized C, so they are compiled with -std=c90. This will emit errors if C++ style comments, the keyword 'inline', etc. are used. Please use C style comments (/* ... */), '__inline__', etc. in UAPI headers. There is additional compiler requirement to enable this test because many of UAPI headers include <stdlib.h>, <sys/ioctl.h>, <sys/time.h>, etc. directly or indirectly. You cannot use kernel.org pre-built toolchains [1] since they lack <stdlib.h>. I reused CONFIG_CC_CAN_LINK to check the system header availability. The intention is slightly different, but a compiler that can link userspace programs provide system headers. For now, a lot of headers need to be excluded because they cannot be compiled standalone, but this is a good start point. [1] https://mirrors.edge.kernel.org/pub/tools/crosstool/index.html Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Reviewed-by: Sam Ravnborg <sam@xxxxxxxxxxxx> --- Changes in v4: - Sort the blacklist alphabetically - Add a little more comments - Remove scripts/cc-system-headers.sh and reuse CC_CAN_LINK Changes in v3: None Changes in v2: - Add CONFIG_CPU_{BIG,LITTLE}_ENDIAN guard to avoid build error - Use 'header-test-' instead of 'no-header-test' - Avoid weird 'find' warning when cleaning Makefile | 2 +- init/Kconfig | 10 ++++ usr/.gitignore | 1 - usr/Makefile | 2 + usr/include/.gitignore | 3 + usr/include/Makefile | 131 +++++++++++++++++++++++++++++++++++++++++ 6 files changed, 147 insertions(+), 2 deletions(-) create mode 100644 usr/include/.gitignore create mode 100644 usr/include/Makefile diff --git a/Makefile b/Makefile index 1f35aca4fe05..f23516980796 100644 --- a/Makefile +++ b/Makefile @@ -1363,7 +1363,7 @@ CLEAN_DIRS += $(MODVERDIR) include/ksym CLEAN_FILES += modules.builtin.modinfo # Directories & files removed with 'make mrproper' -MRPROPER_DIRS += include/config usr/include include/generated \ +MRPROPER_DIRS += include/config include/generated \ arch/$(SRCARCH)/include/generated .tmp_objdiff MRPROPER_FILES += .config .config.old .version \ Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS \ diff --git a/init/Kconfig b/init/Kconfig index 2e9813daa2c1..74192de8ada6 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -108,6 +108,16 @@ config HEADER_TEST If you are a developer or tester and want to ensure the requested headers are self-contained, say Y here. Otherwise, choose N. +config UAPI_HEADER_TEST + bool "Compile test UAPI headers" + depends on HEADER_TEST && HEADERS_INSTALL && CC_CAN_LINK + help + Compile test headers exported to user-space to ensure they are + self-contained, i.e. compilable as standalone units. + + If you are a developer or tester and want to ensure the exported + headers are self-contained, say Y here. Otherwise, choose N. + config LOCALVERSION string "Local version - append to kernel release" help diff --git a/usr/.gitignore b/usr/.gitignore index 8e48117a3f3d..be5eae1df7eb 100644 --- a/usr/.gitignore +++ b/usr/.gitignore @@ -7,4 +7,3 @@ initramfs_data.cpio.gz initramfs_data.cpio.bz2 initramfs_data.cpio.lzma initramfs_list -include diff --git a/usr/Makefile b/usr/Makefile index 4a70ae43c9cb..6a89eb019275 100644 --- a/usr/Makefile +++ b/usr/Makefile @@ -56,3 +56,5 @@ $(deps_initramfs): klibcdirs $(obj)/$(datafile_y): $(obj)/gen_init_cpio $(deps_initramfs) klibcdirs $(Q)$(initramfs) -l $(ramfs-input) > $(obj)/$(datafile_d_y) $(call if_changed,initfs) + +subdir-$(CONFIG_UAPI_HEADER_TEST) += include diff --git a/usr/include/.gitignore b/usr/include/.gitignore new file mode 100644 index 000000000000..a0991ff4402b --- /dev/null +++ b/usr/include/.gitignore @@ -0,0 +1,3 @@ +* +!.gitignore +!Makefile diff --git a/usr/include/Makefile b/usr/include/Makefile new file mode 100644 index 000000000000..0f9f92c6016a --- /dev/null +++ b/usr/include/Makefile @@ -0,0 +1,131 @@ +# 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 + +override c_flags = $(UAPI_CFLAGS) -Wp,-MD,$(depfile) -I$(objtree)/usr/include + +# The following are excluded for now because they fail to build. +# +# Do not add a new header to the blacklist without legitimate reason. +# Please consider to fix the header first. +# +# Sorted alphabetically. +header-test- += asm/ipcbuf.h +header-test- += asm/msgbuf.h +header-test- += asm/sembuf.h +header-test- += asm/shmbuf.h +header-test- += asm/signal.h +header-test- += asm/ucontext.h +header-test- += drm/vmwgfx_drm.h +header-test- += linux/am437x-vpfe.h +header-test- += linux/android/binder.h +header-test- += linux/android/binderfs.h +header-test-$(CONFIG_CPU_BIG_ENDIAN) += linux/byteorder/big_endian.h +header-test-$(CONFIG_CPU_LITTLE_ENDIAN) += linux/byteorder/little_endian.h +header-test- += linux/coda.h +header-test- += linux/coda_psdev.h +header-test- += linux/dvb/audio.h +header-test- += linux/dvb/osd.h +header-test- += linux/elfcore.h +header-test- += linux/errqueue.h +header-test- += linux/fsmap.h +header-test- += linux/hdlc/ioctl.h +header-test- += linux/ivtv.h +header-test- += linux/jffs2.h +header-test- += linux/kexec.h +header-test- += linux/matroxfb.h +header-test- += linux/netfilter_bridge/ebtables.h +header-test- += linux/netfilter_ipv4/ipt_LOG.h +header-test- += linux/netfilter_ipv6/ip6t_LOG.h +header-test- += linux/nfc.h +header-test- += linux/nilfs2_ondisk.h +header-test- += linux/omap3isp.h +header-test- += linux/omapfb.h +header-test- += linux/patchkey.h +header-test- += linux/phonet.h +header-test- += linux/reiserfs_xattr.h +header-test- += linux/scc.h +header-test- += linux/sctp.h +header-test- += linux/signal.h +header-test- += linux/sysctl.h +header-test- += linux/usb/audio.h +header-test- += linux/v4l2-mediabus.h +header-test- += linux/v4l2-subdev.h +header-test- += linux/videodev2.h +header-test- += linux/vm_sockets.h +header-test- += misc/ocxl.h +header-test- += mtd/mtd-abi.h +header-test- += scsi/scsi_bsg_fc.h +header-test- += scsi/scsi_netlink.h +header-test- += scsi/scsi_netlink_fc.h +header-test- += sound/asequencer.h +header-test- += sound/asoc.h +header-test- += sound/asound.h +header-test- += sound/compress_offload.h +header-test- += sound/emu10k1.h +header-test- += sound/sfnt_info.h +header-test- += sound/sof/eq.h +header-test- += sound/sof/fw.h +header-test- += sound/sof/header.h +header-test- += sound/sof/manifest.h +header-test- += sound/sof/trace.h +header-test- += xen/evtchn.h +header-test- += xen/gntdev.h +header-test- += xen/privcmd.h + +# More headers are broken in some architectures + +ifeq ($(SRCARCH),arc) +header-test- += linux/bpf_perf_event.h +endif + +ifeq ($(SRCARCH),ia64) +header-test- += asm/setup.h +header-test- += asm/sigcontext.h +header-test- += asm/perfmon.h +header-test- += asm/perfmon_default_smpl.h +header-test- += linux/if_bonding.h +endif + +ifeq ($(SRCARCH),mips) +header-test- += asm/stat.h +endif + +ifeq ($(SRCARCH),powerpc) +header-test- += asm/stat.h +header-test- += linux/bpf_perf_event.h +endif + +ifeq ($(SRCARCH),riscv) +header-test- += linux/bpf_perf_event.h +endif + +ifeq ($(SRCARCH),s390) +header-test- += asm/runtime_instr.h +header-test- += asm/zcrypt.h +endif + +ifeq ($(SRCARCH),sparc) +header-test- += asm/stat.h +header-test- += asm/uctx.h +header-test- += asm/fbio.h +header-test- += asm/openpromio.h +endif + +# asm-generic/*.h is used by asm/*.h, and should not be included directly +header-test- += asm-generic/% + +# The rest are compile-tested +header-test-y += $(filter-out $(header-test-), \ + $(patsubst $(obj)/%,%, $(wildcard \ + $(addprefix $(obj)/, *.h */*.h */*/*.h */*/*/*.h)))) + +# For GNU Make <= 4.2.1, $(wildcard $(obj)/*/) matches to not only directories +# but also regular files. Use $(filter %/, ...) just in case. +clean-dirs += $(patsubst $(obj)/%/,%,$(filter %/, $(wildcard $(obj)/*/))) -- 2.17.1
