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2020-06-17kconfig: unify cc-option and as-optionMasahiro Yamada
cc-option and as-option are almost the same; both pass the flag to $(CC). The main difference is the cc-option stops before the assemble stage (-S option) whereas as-option stops after (-c option). I chose -S because it is slightly faster, but $(cc-option,-gz=zlib) returns a wrong result (https://lkml.org/lkml/2020/6/9/1529). It has been fixed by commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection"), but the assembler should always be invoked for more reliable compiler option tests. However, you cannot simply replace -S with -c because the following code in lib/Kconfig.debug would break: depends on $(cc-option,-gsplit-dwarf) The combination of -c and -gsplit-dwarf does not accept /dev/null as output. $ cat /dev/null | gcc -gsplit-dwarf -S -x c - -o /dev/null $ echo $? 0 $ cat /dev/null | gcc -gsplit-dwarf -c -x c - -o /dev/null objcopy: Warning: '/dev/null' is not an ordinary file $ echo $? 1 $ cat /dev/null | gcc -gsplit-dwarf -c -x c - -o tmp.o $ echo $? 0 There is another flag that creates an separate file based on the object file path: $ cat /dev/null | gcc -ftest-coverage -c -x c - -o /dev/null <stdin>:1: error: cannot open /dev/null.gcno So, we cannot use /dev/null to sink the output. Align the cc-option implementation with scripts/Kbuild.include. With -c option used in cc-option, as-option is unneeded. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Will Deacon <will@kernel.org>
2020-04-09gcc-plugins: drop support for GCC <= 4.7Masahiro Yamada
Nobody was opposed to raising minimum GCC version to 4.8 [1] So, we will drop GCC <= 4.7 support sooner or later. We always use C++ compiler for building plugins for GCC >= 4.8. This commit drops the plugin support for GCC <= 4.7 a bit earlier, which allows us to dump lots of code. [1] https://lkml.org/lkml/2020/1/23/545 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
2020-03-31Merge tag 'arm64-upstream' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux Pull arm64 updates from Catalin Marinas: "The bulk is in-kernel pointer authentication, activity monitors and lots of asm symbol annotations. I also queued the sys_mremap() patch commenting the asymmetry in the address untagging. Summary: - In-kernel Pointer Authentication support (previously only offered to user space). - ARM Activity Monitors (AMU) extension support allowing better CPU utilisation numbers for the scheduler (frequency invariance). - Memory hot-remove support for arm64. - Lots of asm annotations (SYM_*) in preparation for the in-kernel Branch Target Identification (BTI) support. - arm64 perf updates: ARMv8.5-PMU 64-bit counters, refactoring the PMU init callbacks, support for new DT compatibles. - IPv6 header checksum optimisation. - Fixes: SDEI (software delegated exception interface) double-lock on hibernate with shared events. - Minor clean-ups and refactoring: cpu_ops accessor, cpu_do_switch_mm() converted to C, cpufeature finalisation helper. - sys_mremap() comment explaining the asymmetric address untagging behaviour" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (81 commits) mm/mremap: Add comment explaining the untagging behaviour of mremap() arm64: head: Convert install_el2_stub to SYM_INNER_LABEL arm64: Introduce get_cpu_ops() helper function arm64: Rename cpu_read_ops() to init_cpu_ops() arm64: Declare ACPI parking protocol CPU operation if needed arm64: move kimage_vaddr to .rodata arm64: use mov_q instead of literal ldr arm64: Kconfig: verify binutils support for ARM64_PTR_AUTH lkdtm: arm64: test kernel pointer authentication arm64: compile the kernel with ptrauth return address signing kconfig: Add support for 'as-option' arm64: suspend: restore the kernel ptrauth keys arm64: __show_regs: strip PAC from lr in printk arm64: unwind: strip PAC from kernel addresses arm64: mask PAC bits of __builtin_return_address arm64: initialize ptrauth keys for kernel booting task arm64: initialize and switch ptrauth kernel keys arm64: enable ptrauth earlier arm64: cpufeature: handle conflicts based on capability arm64: cpufeature: Move cpu capability helpers inside C file ...
2020-03-18kconfig: Add support for 'as-option'Vincenzo Frascino
Currently kconfig does not have a feature that allows to detect if the used assembler supports a specific compilation option. Introduce 'as-option' to serve this purpose in the context of Kconfig: config X def_bool $(as-option,...) Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Acked-by: Masahiro Yamada <masahiroy@kernel.org> Cc: linux-kbuild@vger.kernel.org Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-03-12kconfig: introduce m32-flag and m64-flagMasahiro Yamada
When a compiler supports multiple architectures, some compiler features can be dependent on the target architecture. This is typical for Clang, which supports multiple LLVM backends. Even for GCC, we need to take care of biarch compiler cases. It is not a problem when we evaluate cc-option in Makefiles because cc-option is tested against the flag in question + $(KBUILD_CFLAGS). The cc-option in Kconfig, on the other hand, does not accumulate tested flags. Due to this simplification, it could potentially test cc-option against a different target. At first, Kconfig always evaluated cc-option against the host architecture. Since commit e8de12fb7cde ("kbuild: Check for unknown options with cc-option usage in Kconfig and clang"), in case of cross-compiling with Clang, the target triple is correctly passed to Kconfig. The case with biarch GCC (and native build with Clang) is still not handled properly. We need to pass some flags to specify the target machine bit. Due to the design, all the macros in Kconfig are expanded in the parse stage, where we do not know the target bit size yet. For example, arch/x86/Kconfig allows a user to toggle CONFIG_64BIT. If a compiler flag -foo depends on the machine bit, it must be tested twice, one with -m32 and the other with -m64. However, -m32/-m64 are not always recognized. So, this commits adds m64-flag and m32-flag macros. They expand to -m32, -m64, respectively if supported. Or, they expand to an empty string if unsupported. The typical usage is like this: config FOO bool default $(cc-option,$(m64-flag) -foo) if 64BIT default $(cc-option,$(m32-flag) -foo) This is clumsy, but there is no elegant way to handle this in the current static macro expansion. There was discussion for static functions vs dynamic functions. The consensus was to go as far as possible with the static functions. (https://lkml.org/lkml/2018/3/2/22) Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: George Spelvin <lkml@sdf.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
2020-02-01Merge tag 'kbuild-v5.6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - detect missing include guard in UAPI headers - do not create orphan built-in.a or obj-y objects - generate modules.builtin more simply, and drop tristate.conf - simplify built-in initramfs creation - make linux-headers deb package thinner - optimize the deb package build script - misc cleanups * tag 'kbuild-v5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits) builddeb: split libc headers deployment out into a function builddeb: split kernel headers deployment out into a function builddeb: remove redundant make for ARCH=um builddeb: avoid invoking sub-shells where possible builddeb: remove redundant $objtree/ builddeb: match temporary directory name to the package name builddeb: remove unneeded files in hdrobjfiles for headers package kbuild: use -S instead of -E for precise cc-option test in Kconfig builddeb: allow selection of .deb compressor kbuild: remove 'Building modules, stage 2.' log kbuild: remove *.tmp file when filechk fails kbuild: remove PYTHON2 variable modpost: assume STT_SPARC_REGISTER is defined gen_initramfs.sh: remove intermediate cpio_list on errors initramfs: refactor the initramfs build rules gen_initramfs.sh: always output cpio even without -o option initramfs: add default_cpio_list, and delete -d option support initramfs: generate dependency list and cpio at the same time initramfs: specify $(src)/gen_initramfs.sh as a prerequisite in Makefile initramfs: make initramfs compression choice non-optional ...
2020-01-22kbuild: use -S instead of -E for precise cc-option test in KconfigMasahiro Yamada
Currently, -E (stop after the preprocessing stage) is used to check whether the given compiler flag is supported. While it is faster than -S (or -c), it can be false-positive. You need to run the compilation proper to check the flag more precisely. For example, -E and -S disagree about the support of "--param asan-instrument-allocas=1". $ gcc -Werror --param asan-instrument-allocas=1 -E -x c /dev/null -o /dev/null $ echo $? 0 $ gcc -Werror --param asan-instrument-allocas=1 -S -x c /dev/null -o /dev/null cc1: error: invalid --param name ‘asan-instrument-allocas’; did you mean ‘asan-instrument-writes’? $ echo $? 1 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-01-15kbuild: Add support for 'as-instr' to be used in Kconfig filesCatalin Marinas
Similar to 'cc-option' or 'ld-option', it is occasionally necessary to check whether the assembler supports certain ISA extensions. In the arm64 code we currently do this in Makefile with an additional define: lseinstr := $(call as-instr,.arch_extension lse,-DCONFIG_AS_LSE=1) Add the 'as-instr' option so that it can be used in Kconfig directly: def_bool $(as-instr,.arch_extension lse) Acked-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com> Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
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>
2019-08-01kbuild: 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>
2019-05-21treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner
Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-18kbuild: terminate Kconfig when $(CC) or $(LD) is missingMasahiro Yamada
If the compiler specified by $(CC) is not present, the Kconfig stage sprinkles 'not found' messages, then succeeds. $ make CROSS_COMPILE=foo defconfig /bin/sh: 1: foogcc: not found /bin/sh: 1: foogcc: not found *** Default configuration is based on 'x86_64_defconfig' ./scripts/gcc-version.sh: 17: ./scripts/gcc-version.sh: foogcc: not found ./scripts/gcc-version.sh: 18: ./scripts/gcc-version.sh: foogcc: not found ./scripts/gcc-version.sh: 19: ./scripts/gcc-version.sh: foogcc: not found ./scripts/gcc-version.sh: 17: ./scripts/gcc-version.sh: foogcc: not found ./scripts/gcc-version.sh: 18: ./scripts/gcc-version.sh: foogcc: not found ./scripts/gcc-version.sh: 19: ./scripts/gcc-version.sh: foogcc: not found ./scripts/clang-version.sh: 11: ./scripts/clang-version.sh: foogcc: not found ./scripts/gcc-plugin.sh: 11: ./scripts/gcc-plugin.sh: foogcc: not found init/Kconfig:16:warning: 'GCC_VERSION': number is invalid # # configuration written to .config # Terminate parsing files immediately if $(CC) or $(LD) is not found. "make *config" will fail more nicely. $ make CROSS_COMPILE=foo defconfig *** Default configuration is based on 'x86_64_defconfig' scripts/Kconfig.include:34: compiler 'foogcc' not found make[1]: *** [scripts/kconfig/Makefile;82: defconfig] Error 1 make: *** [Makefile;557: defconfig] Error 2 Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-03-04kbuild: clean up scripts/gcc-version.shMasahiro Yamada
Now that the Kconfig is the only user of this script, we can drop unneeded code. Remove the -p option, and stop prepending the output with zero, so that Kconfig can directly use the output from this script. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-06-11gcc-plugins: test plugin support in Kconfig and clean up MakefileMasahiro Yamada
Run scripts/gcc-plugin.sh from Kconfig so that users can enable GCC_PLUGINS only when the compiler supports building plugins. Kconfig defines a new symbol, PLUGIN_HOSTCC. This will contain the compiler (g++ or gcc) used for building plugins, or empty if the plugin can not be supported at all. This allows us to remove all ugly testing in Makefile.gcc-plugins. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Kees Cook <keescook@chromium.org>
2018-05-29kconfig: add basic helper macros to scripts/Kconfig.includeMasahiro Yamada
Kconfig got text processing tools like we see in Make. Add Kconfig helper macros to scripts/Kconfig.include like we collect Makefile macros in scripts/Kbuild.include. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Ulf Magnusson <ulfalizer@gmail.com>