user/sven/linux.git/scripts/Makefile.build, branch v6.1.83

kbuild: add -fno-discard-value-names to cmd_cc_ll_c

2022-10-14T20:22:29Z

When debugging LLVM IR, it can be handy for clang to not discard value names used for local variables and parameters. Compare the generated IR. -fdiscard-value-names: define i32 @core_sys_select(i32 %0, ptr %1, ptr %2, ptr %3, ptr %4) { %6 = alloca i64 %7 = alloca %struct.poll_wqueues %8 = alloca [64 x i32] -fno-discard-value-names: define i32 @core_sys_select(i32 %n, ptr %inp, ptr %outp, ptr %exp, ptr %end_time) { %expire.i = alloca i64 %table.i = alloca %struct.poll_wqueues %stack_fds = alloca [64 x i32] The rule for generating human readable LLVM IR (.ll) is only useful as a debugging feature: $ make LLVM=1 fs/select.ll As Fangrui notes: A LLVM_ENABLE_ASSERTIONS=off build of Clang defaults to -fdiscard-value-names. A LLVM_ENABLE_ASSERTIONS=on build of Clang defaults to -fno-discard-value-names. Explicitly enable -fno-discard-value-names so that the IR always contains value names regardless of whether assertions were enabled or not. Assertions generally are not enabled in releases of clang packaged by distributions. Link: https://github.com/ClangBuiltLinux/linux/issues/1467 Reviewed-by: Nathan Chancellor Reviewed-by: Fangrui Song Signed-off-by: Nick Desaulniers Signed-off-by: Masahiro Yamada

Merge tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2022-10-10T19:00:45Z

Pull Kbuild updates from Masahiro Yamada: - Remove potentially incomplete targets when Kbuid is interrupted by SIGINT etc in case GNU Make may miss to do that when stderr is piped to another program. - Rewrite the single target build so it works more correctly. - Fix rpm-pkg builds with V=1. - List top-level subdirectories in ./Kbuild. - Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in kallsyms. - Avoid two different modules in lib/zstd/ having shared code, which potentially causes building the common code as build-in and modular back-and-forth. - Unify two modpost invocations to optimize the build process. - Remove head-y syntax in favor of linker scripts for placing particular sections in the head of vmlinux. - Bump the minimal GNU Make version to 3.82. - Clean up misc Makefiles and scripts. * tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits) docs: bump minimal GNU Make version to 3.82 ia64: simplify esi object addition in Makefile Revert "kbuild: Check if linker supports the -X option" kbuild: rebuild .vmlinux.export.o when its prerequisite is updated kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o zstd: Fixing mixed module-builtin objects kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols kallsyms: take the input file instead of reading stdin kallsyms: drop duplicated ignore patterns from kallsyms.c kbuild: reuse mksysmap output for kallsyms mksysmap: update comment about __crc_* kbuild: remove head-y syntax kbuild: use obj-y instead extra-y for objects placed at the head kbuild: hide error checker logs for V=1 builds kbuild: re-run modpost when it is updated kbuild: unify two modpost invocations kbuild: move vmlinux.o rule to the top Makefile kbuild: move .vmlinux.objs rule to Makefile.modpost kbuild: list sub-directories in ./Kbuild Makefile.compiler: replace cc-ifversion with compiler-specific macros ...

kbuild: fix and refactor single target build

2022-09-28T19:40:15Z

The single target build has a subtle bug for the combination for an individual file and a subdirectory. [1] 'make kernel/fork.i' builds only kernel/fork.i $ make kernel/fork.i CALL scripts/checksyscalls.sh DESCEND objtool CPP kernel/fork.i [2] 'make kernel/' builds only under the kernel/ directory. $ make kernel/ CALL scripts/checksyscalls.sh DESCEND objtool CC kernel/fork.o CC kernel/exec_domain.o [snip] CC kernel/rseq.o AR kernel/built-in.a But, if you try to do [1] and [2] in a single command, you will get only [1] with a weird log: $ make kernel/fork.i kernel/ CALL scripts/checksyscalls.sh DESCEND objtool CPP kernel/fork.i make[2]: Nothing to be done for 'kernel/'. With 'make kernel/fork.i kernel/', you should get both [1] and [2]. Rewrite the single target build. Signed-off-by: Masahiro Yamada

kbuild: do not deduplicate modules.order

2022-09-28T19:40:14Z

The AWK code was added to deduplicate modules.order in case $(obj-m) contains the same module multiple times, but it is actually unneeded since commit b2c885549122 ("kbuild: update modules.order only when contained modules are updated"). The list is already deduplicated before being processed by AWK because $^ is the deduplicated list of prerequisites. (Please note the real-prereqs macro uses $^) Yet, modules.order will contain duplication if two different Makefiles build the same module: foo/Makefile: obj-m += bar/baz.o foo/bar/Makefile: obj-m += baz.o However, the parallel builds cannot properly handle this case in the first place. So, it is better to let it fail (as already done by scripts/modules-check.sh). Signed-off-by: Masahiro Yamada

Kbuild: add Rust support

2022-09-28T07:02:20Z

Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers Reviewed-by: Greg Kroah-Hartman Co-developed-by: Alex Gaynor Signed-off-by: Alex Gaynor Co-developed-by: Finn Behrens Signed-off-by: Finn Behrens Co-developed-by: Adam Bratschi-Kaye Signed-off-by: Adam Bratschi-Kaye Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Michael Ellerman Signed-off-by: Michael Ellerman Co-developed-by: Sven Van Asbroeck Signed-off-by: Sven Van Asbroeck Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Boris-Chengbiao Zhou Signed-off-by: Boris-Chengbiao Zhou Co-developed-by: Boqun Feng Signed-off-by: Boqun Feng Co-developed-by: Douglas Su Signed-off-by: Douglas Su Co-developed-by: Dariusz Sosnowski Signed-off-by: Dariusz Sosnowski Co-developed-by: Antonio Terceiro Signed-off-by: Antonio Terceiro Co-developed-by: Daniel Xu Signed-off-by: Daniel Xu Co-developed-by: Björn Roy Baron Signed-off-by: Björn Roy Baron Co-developed-by: Martin Rodriguez Reboredo Signed-off-by: Martin Rodriguez Reboredo Signed-off-by: Miguel Ojeda

kbuild: remove sed command from cmd_ar_builtin

2022-07-27T12:17:59Z

Replace a pipeline of echo and sed with printf to decrease process forks. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers

kbuild: avoid regex RS for POSIX awk

2022-06-07T16:27:26Z

In 22f26f21774f8 awk was added to deduplicate *.mod files. The awk invocation passes -v RS='( |\n)' to match a space or newline character as the record separator. Unfortunately, POSIX states[1] > If RS contains more than one character, the results are unspecified. Some implementations (such as the One True Awk[2] used by the BSDs) do not treat RS as a regular expression. When awk does not support regex RS, build failures such as the following are produced (first error using allmodconfig): CC [M] arch/x86/events/intel/uncore.o CC [M] arch/x86/events/intel/uncore_nhmex.o CC [M] arch/x86/events/intel/uncore_snb.o CC [M] arch/x86/events/intel/uncore_snbep.o CC [M] arch/x86/events/intel/uncore_discovery.o LD [M] arch/x86/events/intel/intel-uncore.o ld: cannot find uncore_nhmex.o: No such file or directory ld: cannot find uncore_snb.o: No such file or directory ld: cannot find uncore_snbep.o: No such file or directory ld: cannot find uncore_discovery.o: No such file or directory make[3]: *** [scripts/Makefile.build:422: arch/x86/events/intel/intel-uncore.o] Error 1 make[2]: *** [scripts/Makefile.build:487: arch/x86/events/intel] Error 2 make[1]: *** [scripts/Makefile.build:487: arch/x86/events] Error 2 make: *** [Makefile:1839: arch/x86] Error 2 To avoid this, use printf(1) to produce a newline between each object path, instead of the space produced by echo(1), so that the default RS can be used by awk. [1]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/awk.html [2]: https://github.com/onetrueawk/awk Fixes: 22f26f21774f ("kbuild: get rid of duplication in *.mod files") Signed-off-by: Kevin Locke Signed-off-by: Masahiro Yamada

kbuild: factor out the common objtool arguments

2022-06-04T21:20:57Z

scripts/Makefile.build and scripts/link-vmlinux.sh have similar setups for the objtool arguments. It was difficult to factor out them because all the vmlinux build rules were written in a shell script. It is somewhat tedious to touch the two files every time a new objtool option is supported. To reduce the code duplication, move the objtool for vmlinux.o into scripts/Makefile.vmlinux_o. Then, move the common macros to Makefile.lib so they are shared between Makefile.build and Makefile.vmlinux_o. Signed-off-by: Masahiro Yamada Tested-by: Sedat Dilek # LLVM-14 (x86-64)

kbuild: rebuild multi-object modules when objtool is updated

2022-06-01T14:07:29Z

When CONFIG_LTO_CLANG or CONFIG_X86_KERNEL_IBT is enabled, objtool for multi-object modules is postponed until the objects are linked together. Make sure to re-run objtool and re-link multi-object modules when objtool is updated. Signed-off-by: Masahiro Yamada Reviewed-by: Kees Cook Acked-by: Josh Poimboeuf Tested-by: Nathan Chancellor Reviewed-by: Nicolas Schier Tested-by: Sedat Dilek # LLVM-14 (x86-64)

kbuild: make *.mod rule robust against too long argument error

2022-06-01T14:07:29Z

Like built-in.a, the command length of the *.mod rule scales with the depth of the directory times the number of objects in the Makefile. Add $(obj)/ by the shell command (awk) instead of by Make's builtin function. In-tree modules still have some room to the limit (ARG_MAX=2097152), but this is more future-proof for big modules in a deep directory. For example, you can build i915 as a module (CONFIG_DRM_I915=m) and compare drivers/gpu/drm/i915/.i915.mod.cmd with/without this commit. The issue is more critical for external modules because the M= path can be very long as Jeff Johnson reported before [1]. [1] https://lore.kernel.org/linux-kbuild/4c02050c4e95e4cb8cc04282695f8404@codeaurora.org/ Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Tested-by: Nathan Chancellor Tested-by: Sedat Dilek # LLVM-14 (x86-64)