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2019-09-14genksyms: convert to SPDX License Identifier for lex.l and parse.yMasahiro Yamada
I used the C comment style (/* ... */) for the flex and bison files as in Kconfig (scripts/kconfig/{lexer.l,parser.y}) Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-14modpost: use __section in the output to *.mod.cMasahiro Yamada
Use the __section() shorthand. This avoids escaping double-quotes, and improves the readability. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-14modpost: use MODULE_INFO() for __module_dependsMasahiro Yamada
This makes *.mod.c much more readable. I confirmed depmod still produced the same modules.dep file. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-14export.h, genksyms: do not make genksyms calculate CRC of trimmed symbolsMasahiro Yamada
Arnd Bergmann reported false-positive modpost warnings detected by his randconfig testing of linux-next. Actually, this happens under the combination of CONFIG_MODVERSIONS and CONFIG_TRIM_UNUSED_KSYMS since commit 15bfc2348d54 ("modpost: check for static EXPORT_SYMBOL* functions"). For example, arch/arm/config/multi_v7_defconfig + CONFIG_MODVERSIONS + CONFIG_TRIM_UNUSED_KSYMS produces the following false-positives: WARNING: "__lshrdi3" [vmlinux] is a static (unknown) WARNING: "__ashrdi3" [vmlinux] is a static (unknown) WARNING: "__aeabi_lasr" [vmlinux] is a static (unknown) WARNING: "__aeabi_llsr" [vmlinux] is a static (unknown) WARNING: "ftrace_set_clr_event" [vmlinux] is a static (unknown) WARNING: "__muldi3" [vmlinux] is a static (unknown) WARNING: "__aeabi_ulcmp" [vmlinux] is a static (unknown) WARNING: "__ucmpdi2" [vmlinux] is a static (unknown) WARNING: "__aeabi_lmul" [vmlinux] is a static (unknown) WARNING: "__bswapsi2" [vmlinux] is a static (unknown) WARNING: "__bswapdi2" [vmlinux] is a static (unknown) WARNING: "__ashldi3" [vmlinux] is a static (unknown) WARNING: "__aeabi_llsl" [vmlinux] is a static (unknown) The root cause of the problem is not in the modpost, but in the implementation of CONFIG_TRIM_UNUSED_KSYMS. If there is at least one untrimmed symbol in the file, genksyms is invoked to calculate CRC of *all* the exported symbols in that file even if some of them have been trimmed due to no caller existing. As a result, .tmp_*.ver files contain CRC of trimmed symbols, thus unneeded, orphan __crc* symbols are added to objects. It had been harmless until recently. With commit 15bfc2348d54 ("modpost: check for static EXPORT_SYMBOL* functions"), it is now harmful because the bogus __crc* symbols make modpost call sym_update_crc() to add the symbols to the hash table, but there is no one that clears the ->is_static member. I gave Fixes to the first commit that uncovered the issue, but the potential problem has long existed since commit f235541699bc ("export.h: allow for per-symbol configurable EXPORT_SYMBOL()"). Fixes: 15bfc2348d54 ("modpost: check for static EXPORT_SYMBOL* functions") Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Arnd Bergmann <arnd@arndb.de>
2019-09-09kbuild: allow Clang to find unused static inline functions for W=1 buildMasahiro Yamada
GCC and Clang have different policy for -Wunused-function; GCC does not warn unused static inline functions at all whereas Clang does if they are defined in source files instead of included headers although it has been suppressed since commit abb2ea7dfd82 ("compiler, clang: suppress warning for unused static inline functions"). We often miss to delete unused functions where 'static inline' is used in *.c files since there is no tool to detect them. Unused code remains until somebody notices. For example, commit 075ddd75680f ("regulator: core: remove unused rdev_get_supply()"). Let's remove __maybe_unused from the inline macro to allow Clang to start finding unused static inline functions. For now, we do this only for W=1 build since it is not a good idea to sprinkle warnings for the normal build (e.g. 35 warnings for arch/x86/configs/x86_64_defconfig). My initial attempt was to add -Wno-unused-function for no W= build (https://lore.kernel.org/patchwork/patch/1120594/) Nathan Chancellor pointed out that would weaken Clang's checks since we would no longer get -Wunused-function without W=1. It is true GCC would catch unused static non-inline functions, but it would weaken Clang as a standalone compiler, at least. Hence, here is a counter implementation. The current problem is, W=... only controls compiler flags, which are globally effective. There is no way to address only 'static inline' functions. This commit defines KBUILD_EXTRA_WARN[123] corresponding to W=[123]. When KBUILD_EXTRA_WARN1 is defined, __maybe_unused is omitted from the 'inline' macro. The new macro __inline_maybe_unused makes the code a bit uglier, so I hope we can remove it entirely after fixing most of the warnings. If you contribute to code clean-up, please run "make CC=clang W=1" and check -Wunused-function warnings. You will find lots of unused functions. Some of them are false-positives because the call-sites are disabled by #ifdef. I do not like to abuse the inline keyword for suppressing unused-function warnings because it is intended to be a hint for the compiler optimization. I prefer #ifdef around the definition, or __maybe_unused if #ifdef would make the code too ugly. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com>
2019-09-06kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARNMasahiro Yamada
KBUILD_ENABLE_EXTRA_GCC_CHECKS started as a switch to add extra warning options for GCC, but now it is a historical misnomer since we use it also for Clang, DTC, and even kernel-doc. Rename it to more sensible, shorter KBUILD_EXTRA_WARN. For the backward compatibility, KBUILD_ENABLE_EXTRA_GCC_CHECKS is still supported (but not advertised in the documentation). I also fixed up 'make help', and updated the documentation. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
2019-09-06kbuild: refactor scripts/Makefile.extrawarnMasahiro Yamada
Instead of the warning-[123] magic, let's accumulate compiler options to KBUILD_CFLAGS directly as the top Makefile does. I think this makes it easier to understand what is going on in this file. This commit slightly changes the behavior, I think all of which are OK. [1] Currently, cc-option calls are needlessly evaluated. For example, warning-3 += $(call cc-option, -Wpacked-bitfield-compat) needs evaluating only when W=3, but it is actually evaluated for W=1, W=2 as well. With this commit, only relevant cc-option calls will be evaluated. This is a slight optimization. [2] Currently, unsupported level like W=4 is checked by: $(error W=$(KBUILD_ENABLE_EXTRA_GCC_CHECKS) is unknown) This will no longer be checked, but I do not think it is a big deal. [3] Currently, 4 Clang warnings (Winitializer-overrides, Wformat, Wsign-compare, Wformat-zero-length) are shown by any of W=1, W=2, and W=3. With this commit, they will be warned only by W=1. I think this is a more correct behavior since each warning belongs to only one group. For understanding this commit correctly: We have 3 warning groups, W=1, W=2, and W=3. You may think W=3 has a higher level than W=1, but they are actually independent. If you like, you can combine them like W=13. To enable all the warnings, you can pass W=123. It is shown by 'make help', but not noticed much. Since we support W= combination, there should not exist intersection among the three groups. If we enable Winitializer-overrides for W=1, we do not need to for W=2 or W=3. This is the reason why I think the change [3] makes sense. The documentation says -Winitializer-overrides is enabled by default. (https://clang.llvm.org/docs/DiagnosticsReference.html#winitializer-overrides) We negate it by passing -Wno-initializer-overrides for the normal build, but we do not do that for W=1. This means, W=1 effectively enables -Winitializer-overrides by the clang's default. The same for the other three. Add comments in case people are confused with the code. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
2019-09-04merge_config.sh: ignore unwanted grep errorsGuillaume Tucker
The merge_config.sh script verifies that all the config options have their expected value in the resulting file and prints any issues as warnings. These checks aren't intended to be treated as errors given the current implementation. However, since "set -e" was added, if the grep command to look for a config option does not find it the script will then abort prematurely. Handle the case where the grep exit status is non-zero by setting ACTUAL_VAL to an empty string to restore previous functionality. Fixes: cdfca821571d ("merge_config.sh: Check error codes from make") Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com> Acked-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-04kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)Masahiro Yamada
Kbuild provides per-file compiler flag addition/removal: CFLAGS_<basetarget>.o CFLAGS_REMOVE_<basetarget>.o AFLAGS_<basetarget>.o AFLAGS_REMOVE_<basetarget>.o CPPFLAGS_<basetarget>.lds HOSTCFLAGS_<basetarget>.o HOSTCXXFLAGS_<basetarget>.o The <basetarget> is the filename of the target with its directory and suffix stripped. This syntax comes into a trouble when two files with the same basename appear in one Makefile, for example: obj-y += foo.o obj-y += dir/foo.o CFLAGS_foo.o := <some-flags> Here, the <some-flags> applies to both foo.o and dir/foo.o The real world problem is: scripts/kconfig/util.c scripts/kconfig/lxdialog/util.c Both files are compiled into scripts/kconfig/mconf, but only the latter should be given with the ncurses flags. It is more sensible to use the relative path to the Makefile, like this: obj-y += foo.o CFLAGS_foo.o := <some-flags> obj-y += dir/foo.o CFLAGS_dir/foo.o := <other-flags> At first, I attempted to replace $(basetarget) with $*. The $* variable is replaced with the stem ('%') part in a pattern rule. This works with most of cases, but does not for explicit rules. For example, arch/ia64/lib/Makefile reuses rule_as_o_S in its own explicit rules, so $* will be empty, resulting in ignoring the per-file AFLAGS. I introduced a new variable, target-stem, which can be used also from explicit rules. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Marc Zyngier <maz@kernel.org>
2019-09-04modpost: add NOFAIL to strndupDenis Efremov
Add NOFAIL check for the strndup call, because the function allocates memory and can return NULL. All calls to strdup in modpost are checked with NOFAIL. Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-04modpost: add guid_t type definitionHeikki Krogerus
Since guid_t is the recommended data type for UUIDs in kernel (and I guess uuid_le is meant to be ultimately replaced with it), it should be made available here as well. Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-09-04kbuild: add $(BASH) to run scripts with bash-extensionMasahiro Yamada
CONFIG_SHELL falls back to sh when bash is not installed on the system, but nobody is testing such a case since bash is usually installed. So, shell scripts invoked by CONFIG_SHELL are only tested with bash. It makes it difficult to test whether the hashbang #!/bin/sh is real. For example, #!/bin/sh in arch/powerpc/kernel/prom_init_check.sh is false. (I fixed it up) Besides, some shell scripts invoked by CONFIG_SHELL use bash-extension and #!/bin/bash is specified as the hashbang, while CONFIG_SHELL may not always be set to bash. Probably, the right thing to do is to introduce BASH, which is bash by default, and always set CONFIG_SHELL to sh. Replace $(CONFIG_SHELL) with $(BASH) for bash scripts. If somebody tries to add bash-extension to a #!/bin/sh script, it will be caught in testing because /bin/sh is a symlink to dash on some major distributions. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29kbuild: clean up subdir-ymn calculation in Makefile.cleanMasahiro Yamada
Remove some variables. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29kbuild: remove unneeded '+' marker from cmd_cleanMasahiro Yamada
This '+' was added a long time ago: | commit c23e6bf05f7802e92fd3da69a1ed35e56f9c85bb (HEAD) | Author: Kai Germaschewski <kai@tp1.ruhr-uni-bochum.de> | Date: Mon Oct 28 01:16:34 2002 -0600 | | kbuild: Fix a "make -j<N>" warning | | diff --git a/scripts/Makefile.clean b/scripts/Makefile.clean | index 2c843e0380bc..e7c392fd5788 100644 | --- a/scripts/Makefile.clean | +++ b/scripts/Makefile.clean | @@ -42,7 +42,7 @@ quiet_cmd_clean = CLEAN $(obj) | | __clean: $(subdir-ymn) | ifneq ($(strip $(__clean-files) $(clean-rule)),) | - $(call cmd,clean) | + +$(call cmd,clean) | else | @: | endif At that time, cmd_clean contained $(clean-rule), which was able to invoke sub-make. That was why cleaning with the -j option showed: warning: jobserver unavailable: using -j1. Add '+' to parent make rule. It is not the case any more; cmd_clean now just runs the 'rm' command. The '+' marker is pointless. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29kbuild: remove clean-dirs syntaxMasahiro Yamada
The only the difference between clean-files and clean-dirs is the -r option passed to the 'rm' command. You can always pass -r, and then remove the clean-dirs syntax. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29kbuild: get rid of $(realpath ...) from scripts/mkmakefileMasahiro Yamada
Both relative path and absolute path have pros and cons. For example, we can move the source and objtree around together by using the relative path to the source tree. Do not force the absolute path to the source tree. If you prefer the absolute path, you can specify KBUILD_ABS_SRCTREE=1. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-29kbuild: remove unneeded comments and code from scripts/basic/MakefileMasahiro Yamada
Kbuild descends into scripts/basic/ even before the Kconfig. I do not expect any other host programs added to this Makefile. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-25kbuild: pkg: rename scripts/package/Makefile to scripts/Makefile.packageMasahiro Yamada
scripts/package/Makefile does not use $(obj) or $(src) at all. It actually generates files and directories in the top of $(objtree). I do not see much sense in descending into scripts/package/. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-25kbuild: pkg: add package targets to PHONY instead of FORCEMasahiro Yamada
These are not real targets. Adding them to PHONY is preferred. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-25kbuild: pkg: clean up package files/dirs from the top MakefileMasahiro Yamada
I am not a big fan of the $(objtree)/ hack for clean-files/clean-dirs. These are created in the top of $(objtree), so let's clean them up from the top Makefile. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-22merge_config.sh: Check error codes from makeMark Brown
When we execute make after merging the configurations we ignore any errors it produces causing whatever is running merge_config.sh to be unaware of any failures. This issue was noticed by Guillaume Tucker while looking at problems with testing of clang only builds in KernelCI which caused Kbuild to be unable to find a working host compiler. This implementation was suggested by Yamada-san. Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reported-by: Guillaume Tucker <guillaume.tucker@collabora.com> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-22kbuild: move modkern_{c,a}flags to Makefile.lib from Makefile.buildMasahiro Yamada
Makefile.lib is included by Makefile.modfinal as well as Makefile.build. Move modkern_cflags to Makefile.lib in order to simplify cmd_cc_o_c in Makefile.modfinal. Move modkern_cflags as well for consistency. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-22kbuild: add CONFIG_ASM_MODVERSIONSMasahiro Yamada
Add CONFIG_ASM_MODVERSIONS. This allows to remove one if-conditional nesting in scripts/Makefile.build. scripts/Makefile.build is run every time Kbuild descends into a sub-directory. So, I want to avoid $(wildcard ...) evaluation where possible although computing $(wildcard ...) is so cheap that it may not make measurable performance difference. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
2019-08-22kbuild: split final module linking out into Makefile.modfinalMasahiro Yamada
I think splitting the modpost and linking modules into separate Makefiles will be useful especially when more complex build steps come in. The main motivation of this commit is to integrate the proposed klp-convert feature cleanly. I moved the logging 'Building modules, stage 2.' to Makefile.modpost to avoid the code duplication although I do not know whether or not this message is needed in the first place. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21kbuild: rebuild modules when module linker scripts are updatedMasahiro Yamada
Currently, the timestamp of module linker scripts are not checked. Add them to the dependency of modules so they are correctly rebuilt. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21kbuild: make single targets work more correctlyMasahiro Yamada
Currently, the single target build directly descends into the directory of the target. For example, $ make foo/bar/baz.o ... directly descends into foo/bar/. On the other hand, the normal build usually descends one directory at a time, i.e. descends into foo/, and then foo/bar/. This difference causes some problems. [1] miss subdir-asflags-y, subdir-ccflags-y in upper Makefiles The options in subdir-{as,cc}flags-y take effect in the current and its sub-directories. In other words, they are inherited downward. In the example above, the single target will miss subdir-{as,cc}flags-y if they are defined in foo/Makefile. [2] could be built in a different directory As Documentation/kbuild/modules.rst section 4.3 says, Kbuild can handle files that are spread over several sub-directories. The build rule of foo/bar/baz.o may not necessarily be specified in foo/bar/Makefile. It might be specifies in foo/Makefile as follows: [foo/Makefile] obj-y := bar/baz.o This often happens when a module is so big that its source files are divided into sub-directories. In this case, there is no Makefile in the foo/bar/ directory, yet the single target descends into foo/bar/, then fails due to the missing Makefile. You can still do 'make foo/bar/' for partial building, but cannot do 'make foo/bar/baz.s'. I believe the single target '%.s' is a useful feature for inspecting the compiler output. Some modules work around this issue by putting an empty Makefile in every sub-directory. This commit fixes those problems by making the single target build descend in the same way as the normal build does. Another change is the single target build will observe the CONFIG options. Previously, it allowed users to build the foo.o even when the corresponding CONFIG_FOO is disabled: obj-$(CONFIG_FOO) += foo.o In the new behavior, the single target build will just fail and show "No rule to make target ..." (or "Nothing to be done for ..." if the stale object already exists, but cannot be updated). The disadvantage of this commit is the build speed. Now that the single target build visits every directory and parses lots of Makefiles, it is slower than before. (But, I hope it will not be too slow.) Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21kbuild: Parameterize kallsyms generation and correct reportingKees Cook
When kallsyms generation happens, temporary vmlinux outputs are linked but the quiet make output didn't report it, giving the impression that the prior command is taking longer than expected. Instead, report the linking step explicitly. While at it, this consolidates the repeated "kallsyms generation step" into a single function and removes the existing copy/pasting. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-21kbuild: re-implement detection of CONFIG options leaked to user-spaceMasahiro Yamada
scripts/headers_check.pl can detect references to CONFIG options in exported headers, but it has been disabled for more than a decade. Reverting commit 7e3fa5614117 ("kbuild: drop check for CONFIG_ in headers_check") would emit the following warnings for headers_check on x86: usr/include/mtd/ubi-user.h:283: leaks CONFIG_MTD_UBI_BEB_LIMIT to userspace where it is not valid usr/include/linux/cm4000_cs.h:26: leaks CONFIG_COMPAT to userspace where it is not valid usr/include/linux/pkt_cls.h:301: leaks CONFIG_NET_CLS_ACT to userspace where it is not valid usr/include/linux/videodev2.h:2465: leaks CONFIG_VIDEO_ADV_DEBUG to userspace where it is not valid usr/include/linux/bpf.h:249: leaks CONFIG_EFFICIENT_UNALIGNED_ACCESS to userspace where it is not valid usr/include/linux/bpf.h:819: leaks CONFIG_CGROUP_NET_CLASSID to userspace where it is not valid usr/include/linux/bpf.h:1011: leaks CONFIG_IP_ROUTE_CLASSID to userspace where it is not valid usr/include/linux/bpf.h:1742: leaks CONFIG_BPF_KPROBE_OVERRIDE to userspace where it is not valid usr/include/linux/bpf.h:1747: leaks CONFIG_FUNCTION_ERROR_INJECTION to userspace where it is not valid usr/include/linux/bpf.h:1936: leaks CONFIG_XFRM to userspace where it is not valid usr/include/linux/bpf.h:2184: leaks CONFIG_BPF_LIRC_MODE2 to userspace where it is not valid usr/include/linux/bpf.h:2210: leaks CONFIG_BPF_LIRC_MODE2 to userspace where it is not valid usr/include/linux/bpf.h:2227: leaks CONFIG_SOCK_CGROUP_DATA to userspace where it is not valid usr/include/linux/bpf.h:2311: leaks CONFIG_NET to userspace where it is not valid usr/include/linux/bpf.h:2348: leaks CONFIG_NET to userspace where it is not valid usr/include/linux/bpf.h:2422: leaks CONFIG_BPF_LIRC_MODE2 to userspace where it is not valid usr/include/linux/bpf.h:2528: leaks CONFIG_NET to userspace where it is not valid usr/include/linux/pktcdvd.h:37: leaks CONFIG_CDROM_PKTCDVD_WCACHE to userspace where it is not valid usr/include/linux/hw_breakpoint.h:27: leaks CONFIG_HAVE_MIXED_BREAKPOINTS_REGS to userspace where it is not valid usr/include/linux/raw.h:17: leaks CONFIG_MAX_RAW_DEVS to userspace where it is not valid usr/include/linux/elfcore.h:62: leaks CONFIG_BINFMT_ELF_FDPIC to userspace where it is not valid usr/include/linux/eventpoll.h:82: leaks CONFIG_PM_SLEEP to userspace where it is not valid usr/include/linux/atmdev.h:104: leaks CONFIG_COMPAT to userspace where it is not valid usr/include/asm-generic/unistd.h:651: leaks CONFIG_MMU to userspace where it is not valid usr/include/asm-generic/bitsperlong.h:9: leaks CONFIG_64BIT to userspace where it is not valid usr/include/asm-generic/fcntl.h:119: leaks CONFIG_64BIT to userspace where it is not valid usr/include/asm/auxvec.h:14: leaks CONFIG_IA32_EMULATION to userspace where it is not valid usr/include/asm/e820.h:14: leaks CONFIG_NODES_SHIFT to userspace where it is not valid usr/include/asm/e820.h:39: leaks CONFIG_X86_PMEM_LEGACY to userspace where it is not valid usr/include/asm/e820.h:49: leaks CONFIG_INTEL_TXT to userspace where it is not valid usr/include/asm/mman.h:7: leaks CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS to userspace where it is not valid Most of these are false positives because scripts/headers_check.pl parses comment lines. It is also false negative. arch/x86/include/uapi/asm/auxvec.h contains CONFIG_IA32_EMULATION and CONFIG_X86_64, but the only former is reported. It would be possible to fix scripts/headers_check.pl, of course. However, we already have some duplicated checks between headers_check and CONFIG_UAPI_HEADER_TEST. At this moment of time, there are still dozens of headers excluded from the header test (usr/include/Makefile), but we might be able to remove headers_check eventually. I re-implemented it in scripts/headers_install.sh by using sed because the most of code in scripts/headers_install.sh is written in sed. This patch works like this: [1] Run scripts/unifdef first because we need to drop the code surrounded by #ifdef __KERNEL__ ... #endif [2] Remove all C style comments. The sed code is somewhat complicated since we need to deal with both single and multi line comments. Precisely speaking, a comment block is replaced with a space just in case. CONFIG_FOO/* this is a comment */CONFIG_BAR should be converted into: CONFIG_FOO CONFIG_BAR instead of: CONFIG_FOOCONFIG_BAR [3] Match CONFIG_... pattern. It correctly matches to all CONFIG options that appear in a single line. After this commit, this would detect the following warnings, all of which are real ones. warning: include/uapi/linux/pktcdvd.h: leak CONFIG_CDROM_PKTCDVD_WCACHE to user-space warning: include/uapi/linux/hw_breakpoint.h: leak CONFIG_HAVE_MIXED_BREAKPOINTS_REGS to user-space warning: include/uapi/linux/raw.h: leak CONFIG_MAX_RAW_DEVS to user-space warning: include/uapi/linux/elfcore.h: leak CONFIG_BINFMT_ELF_FDPIC to user-space warning: include/uapi/linux/eventpoll.h: leak CONFIG_PM_SLEEP to user-space warning: include/uapi/linux/atmdev.h: leak CONFIG_COMPAT to user-space warning: include/uapi/asm-generic/fcntl.h: leak CONFIG_64BIT to user-space warning: arch/x86/include/uapi/asm/auxvec.h: leak CONFIG_IA32_EMULATION to user-space warning: arch/x86/include/uapi/asm/auxvec.h: leak CONFIG_X86_64 to user-space warning: arch/x86/include/uapi/asm/mman.h: leak CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS to user-space However, it is not nice to show them right now. I created a list of existing leakages. They are not warned, but a new leakage will be blocked by the 0-day bot. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Sam Ravnborg <sam@ravnborg.org>
2019-08-15kbuild: fix modkern_aflags implementationMasahiro Yamada
For the single target building %.symtypes from %.S, $(a_flags) is expanded into the _KERNEL flags even if the object is a part of a module. $(real-obj-m:.o=.symtypes): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE) ... would fix the issue, but it is not nice to duplicate similar code for every suffix. Implement modkern_aflags in the same way as modkern_cflags. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-15kbuild: refactor part-of-module moreMasahiro Yamada
Make it even shorter. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-15kbuild: treat an object as multi-used when $(foo-) is setMasahiro Yamada
Currently, Kbuild treats an object as multi-used when any of $(foo-objs), $(foo-y), $(foo-m) is set. It makes more sense to check $(foo-) as well. In the context of foo-$(CONFIG_FOO_FEATURE1), CONFIG_FOO_FEATURE1 could be unset. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14kbuild: add [M] marker for build log of *.mod.oMasahiro Yamada
This builds module objects, so [M] makes sense. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14Kbuild: Handle PREEMPT_RT for version string and magicThomas Gleixner
Update the build scripts and the version magic to reflect when CONFIG_PREEMPT_RT is enabled in the same way as CONFIG_PREEMPT is treated. The resulting version strings: Linux m 5.3.0-rc1+ #100 SMP Fri Jul 26 ... Linux m 5.3.0-rc1+ #101 SMP PREEMPT Fri Jul 26 ... Linux m 5.3.0-rc1+ #102 SMP PREEMPT_RT Fri Jul 26 ... The module vermagic: 5.3.0-rc1+ SMP mod_unload modversions 5.3.0-rc1+ SMP preempt mod_unload modversions 5.3.0-rc1+ SMP preempt_rt mod_unload modversions Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14kbuild: move flex and bison rules to Makefile.hostMasahiro Yamada
Flex and bison are used for kconfig, dtc, genksyms, all of which are host programs. I never imagine the kernel embeds a parser or a lexer. Move the flex and bison rules to scripts/Makefile.host. This file is included only when hostprogs-y etc. is present in the Makefile in the directory. So, parsing these rules are skipped in most of directories. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14kbuild: make bison create C file and header in a single pattern ruleMasahiro Yamada
We generally expect bison to create not only a C file, but also a header, which will be included from the lexer. Currently, Kbuild generates them in separate rules. So, for instance, when building Kconfig, you will notice bison is invoked twice: HOSTCC scripts/kconfig/conf.o HOSTCC scripts/kconfig/confdata.o HOSTCC scripts/kconfig/expr.o LEX scripts/kconfig/lexer.lex.c YACC scripts/kconfig/parser.tab.h HOSTCC scripts/kconfig/lexer.lex.o YACC scripts/kconfig/parser.tab.c HOSTCC scripts/kconfig/parser.tab.o HOSTCC scripts/kconfig/preprocess.o HOSTCC scripts/kconfig/symbol.o HOSTLD scripts/kconfig/conf Make handles such cases nicely in pattern rules [1]. Merge the two rules so that one invokcation of bison can generate both of them. HOSTCC scripts/kconfig/conf.o HOSTCC scripts/kconfig/confdata.o HOSTCC scripts/kconfig/expr.o LEX scripts/kconfig/lexer.lex.c YACC scripts/kconfig/parser.tab.[ch] HOSTCC scripts/kconfig/lexer.lex.o HOSTCC scripts/kconfig/parser.tab.o HOSTCC scripts/kconfig/preprocess.o HOSTCC scripts/kconfig/symbol.o HOSTLD scripts/kconfig/conf [1] Pattern rule GNU Make manual says: "Pattern rules may have more than one target. Unlike normal rules, this does not act as many different rules with the same prerequisites and recipe. If a pattern rule has multiple targets, make knows that the rule's recipe is responsible for making all of the targets. The recipe is executed only once to make all the targets. When searching for a pattern rule to match a target, the target patterns of a rule other than the one that matches the target in need of a rule are incidental: make worries only about giving a recipe and prerequisites to the file presently in question. However, when this file's recipe is run, the other targets are marked as having been updated themselves." https://www.gnu.org/software/make/manual/html_node/Pattern-Intro.html Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14kbuild: use $(basename ...) for cmd_asn1_compilerMasahiro Yamada
$(basename ...) trims the last suffix. Using it is more intuitive in my opinion. This pattern rule makes %.asn1.c and %.asn1.h at the same time. Previously, the short log showed only either of them, depending on the target file in question. To clarify that two files are being generated by the single recipe, I changed the log as follows: Before: ASN.1 crypto/asymmetric_keys/x509.asn1.c After: ASN.1 crypto/asymmetric_keys/x509.asn1.[ch] Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14kbuild: Fail if gold linker is detectedThomas Gleixner
The gold linker has known issues of failing the build both in random and in predictible ways: - The x86/X32 VDSO build fails with: arch/x86/entry/vdso/vclock_gettime-x32.o:vclock_gettime.c:function do_hres: error: relocation overflow: reference to 'hvclock_page' That's a known issue for years and the usual workaround is to disable CONFIG_X86_32 - A recent build failure is caused by turning a relocation into an absolute one for unknown reasons. See link below. - There are a couple of gold workarounds applied already, but reports about broken builds with ld.gold keep coming in on a regular base and in most cases the root cause is unclear. In context of the most recent fail H.J. stated: "Since building a workable kernel for different kernel configurations isn't a requirement for gold, I don't recommend gold for kernel." So instead of dealing with attempts to duct tape gold support without understanding the root cause and without support from the gold folks, fail the build when gold is detected. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/CAMe9rOqMqkQ0LNpm25yE_Yt0FKp05WmHOrwc0aRDb53miFKM+w@mail.gmail.com Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14modpost: check for static EXPORT_SYMBOL* functionsDenis Efremov
This patch adds a check to warn about static EXPORT_SYMBOL* functions during the modpost. In most of the cases, a static symbol marked for exporting is an odd combination that should be fixed either by deleting the exporting mark or by removing the static attribute and adding the appropriate declaration to headers. This check could help to detect the following problems: 1. 550113d4e9f5 ("i2c: add newly exported functions to the header, too") 2. 54638c6eaf44 ("net: phy: make exported variables non-static") 3. 98ef2046f28b ("mm: remove the exporting of totalram_pages") 4. 73df167c819e ("s390/zcrypt: remove the exporting of ap_query_configuration") 5. a57caf8c527f ("sunrpc/cache: remove the exporting of cache_seq_next") 6. e4e4730698c9 ("crypto: skcipher - remove the exporting of skcipher_walk_next") 7. 14b4c48bb1ce ("gve: Remove the exporting of gve_probe") 8. 9b79ee9773a8 ("scsi: libsas: remove the exporting of sas_wait_eh") 9. ... The build time impact is very limited and is almost at the unnoticeable level (< 1 sec). Acked-by: Emil Velikov <emil.l.velikov@gmail.com> Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-10kbuild: show hint if subdir-y/m is used to visit module MakefileMasahiro Yamada
Since commit ff9b45c55b26 ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod"), a module is no longer built in the following pattern: [Makefile] subdir-y := some-module [some-module/Makefile] obj-m := some-module.o You cannot write Makefile this way in upstream because modules.order is not correctly generated. subdir-y is used to descend to a sub-directory that builds tools, device trees, etc. For external modules, the modules order does not matter. So, the Makefile above was known to work. I believe the Makefile should be re-written as follows: [Makefile] obj-m := some-module/ [some-module/Makefile] obj-m := some-module.o However, people will have no idea if their Makefile suddenly stops working. In fact, I received questions from multiple people. Show a warning for a while if obj-m is specified in a Makefile visited by subdir-y or subdir-m. I touched the %/ rule to avoid false-positive warnings for the single target. Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Tom Stonecypher <thomas.edwardx.stonecypher@intel.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Jan Kiszka <jan.kiszka@siemens.com>
2019-08-10kbuild: generate modules.order only in directories visited by obj-y/mMasahiro Yamada
The modules.order files in directories visited by the chain of obj-y or obj-m are merged to the upper-level ones, and become parts of the top-level modules.order. On the other hand, there is no need to generate modules.order in directories visited by subdir-y or subdir-m since they would become orphan anyway. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-10kbuild: fix false-positive need-builtin calculationMasahiro Yamada
The current implementation of need-builtin is false-positive, for example, in the following Makefile: obj-m := foo/ obj-y := foo/bar/ ..., where foo/built-in.a is not required. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-10kbuild: revive single target %.koMasahiro Yamada
I removed the single target %.ko in commit ff9b45c55b26 ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod") because the modpost stage does not work reliably. For instance, the module dependency, modversion, etc. do not work if we lack symbol information from the other modules. Yet, some people still want to build only one module in their interest, and it may be still useful if it is used within those limitations. Fixes: ff9b45c55b26 ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod") Reported-by: Don Brace <don.brace@microsemi.com> Reported-by: Arend Van Spriel <arend.vanspriel@broadcom.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-04kconfig: Clear "written" flag to avoid data lossM. Vefa Bicakci
Prior to this commit, starting nconfig, xconfig or gconfig, and saving the .config file more than once caused data loss, where a .config file that contained only comments would be written to disk starting from the second save operation. This bug manifests itself because the SYMBOL_WRITTEN flag is never cleared after the first call to conf_write, and subsequent calls to conf_write then skip all of the configuration symbols due to the SYMBOL_WRITTEN flag being set. This commit resolves this issue by clearing the SYMBOL_WRITTEN flag from all symbols before conf_write returns. Fixes: 8e2442a5f86e ("kconfig: fix missing choice values in auto.conf") Cc: linux-stable <stable@vger.kernel.org> # 4.19+ Signed-off-by: M. Vefa Bicakci <m.v.b@runbox.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-01kbuild: Check for unknown options with cc-option usage in Kconfig and clangStephen Boyd
If the particular version of clang a user has doesn't enable -Werror=unknown-warning-option by default, even though it is the default[1], then make sure to pass the option to the Kconfig cc-option command so that testing options from Kconfig files works properly. Otherwise, depending on the default values setup in the clang toolchain we will silently assume options such as -Wmaybe-uninitialized are supported by clang, when they really aren't. A compilation issue only started happening for me once commit 589834b3a009 ("kbuild: Add -Werror=unknown-warning-option to CLANG_FLAGS") was applied on top of commit b303c6df80c9 ("kbuild: compute false-positive -Wmaybe-uninitialized cases in Kconfig"). This leads kbuild to try and test for the existence of the -Wmaybe-uninitialized flag with the cc-option command in scripts/Kconfig.include, and it doesn't see an error returned from the option test so it sets the config value to Y. Then the Makefile tries to pass the unknown option on the command line and -Werror=unknown-warning-option catches the invalid option and breaks the build. Before commit 589834b3a009 ("kbuild: Add -Werror=unknown-warning-option to CLANG_FLAGS") the build works fine, but any cc-option test of a warning option in Kconfig files silently evaluates to true, even if the warning option flag isn't supported on clang. Note: This doesn't change cc-option usages in Makefiles because those use a different rule that includes KBUILD_CFLAGS by default (see the __cc-option command in scripts/Kbuild.incluide). The KBUILD_CFLAGS variable already has the -Werror=unknown-warning-option flag set. Thanks to Doug for pointing out the different rule. [1] https://clang.llvm.org/docs/DiagnosticsReference.html#wunknown-warning-option Cc: Peter Smith <peter.smith@linaro.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Douglas Anderson <dianders@chromium.org> Signed-off-by: Stephen Boyd <swboyd@chromium.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-01kbuild: modpost: do not parse unnecessary rules for vmlinux modpostMasahiro Yamada
Since commit ff9b45c55b26 ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod"), 'make vmlinux' emits a warning, like this: $ make defconfig vmlinux [ snip ] LD vmlinux.o cat: modules.order: No such file or directory MODPOST vmlinux.o MODINFO modules.builtin.modinfo KSYM .tmp_kallsyms1.o KSYM .tmp_kallsyms2.o LD vmlinux SORTEX vmlinux SYSMAP System.map When building only vmlinux, KBUILD_MODULES is not set. Hence, the modules.order is not generated. For the vmlinux modpost, it is not necessary at all. Separate scripts/Makefile.modpost for the vmlinux/modules stages. This works more efficiently because the vmlinux modpost does not need to include .*.cmd files. Fixes: ff9b45c55b26 ("kbuild: modpost: read modules.order instead of $(MODVERDIR)/*.mod") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-01kbuild: modpost: remove unnecessary dependency for __modpostMasahiro Yamada
__modpost is a phony target. The dependency on FORCE is pointless. All the objects have been built in the previous stage, so the dependency on the objects are not necessary either. Count the number of modules in a more straightforward way. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-01kbuild: modpost: handle KBUILD_EXTRA_SYMBOLS only for external modulesMasahiro Yamada
KBUILD_EXTRA_SYMBOLS makes sense only when building external modules. Moreover, the modpost sets 'external_module' if the -e option is given. I replaced $(patsubst %, -e %,...) with simpler $(addprefix -e,...) while I was here. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-01kbuild: modpost: include .*.cmd files only when targets existMasahiro Yamada
If a build rule fails, the .DELETE_ON_ERROR special target removes the target, but does nothing for the .*.cmd file, which might be corrupted. So, .*.cmd files should be included only when the corresponding targets exist. Commit 392885ee82d3 ("kbuild: let fixdep directly write to .*.cmd files") missed to fix up this file. Fixes: 392885ee82d3 ("kbuild: let fixdep directly write to .*.cmd") Cc: <stable@vger.kernel.org> # v5.0+ Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-29kbuild: detect missing "WITH Linux-syscall-note" for uapi headersMasahiro Yamada
UAPI headers licensed under GPL are supposed to have exception "WITH Linux-syscall-note" so that they can be included into non-GPL user space application code. Unfortunately, people often miss to add it. Break 'make headers' when any of exported headers lacks the exception note so that the 0-day bot can easily catch it. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-07-28Merge tag 'kbuild-fixes-v5.3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - add compile_commands.json to .gitignore - fix false-positive warning from gen_compile_commands.py after allnoconfig build - remove unused code * tag 'kbuild-fixes-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: remove unused single-used-m gen_compile_commands: lower the entry count threshold .gitignore: Add compilation database file kbuild: remove unused objectify macro