user/sven/linux.git/scripts/Makefile.build, branch v5.4.141

kbuild: Fix objtool dependency for 'OBJECT_FILES_NON_STANDARD_ := n'

2021-07-14T14:53:20Z

[ Upstream commit 8852c552402979508fdc395ae07aa8761aa46045 ] "OBJECT_FILES_NON_STANDARD_vma.o := n" has a dependency bug. When objtool source is updated, the affected object doesn't get re-analyzed by objtool. Peter's new variable-sized jump label feature relies on objtool rewriting the object file. Otherwise the system can fail to boot. That effectively upgrades this minor dependency issue to a major bug. The problem is that variables in prerequisites are expanded early, during the read-in phase. The '$(objtool_dep)' variable indirectly uses '$@', which isn't yet available when the target prerequisites are evaluated. Use '.SECONDEXPANSION:' which causes '$(objtool_dep)' to be expanded in a later phase, after the target-specific '$@' variable has been defined. Fixes: b9ab5ebb14ec ("objtool: Add CONFIG_STACK_VALIDATION option") Fixes: ab3257042c26 ("jump_label, x86: Allow short NOPs") Reported-by: Matthew Wilcox Signed-off-by: Josh Poimboeuf Signed-off-by: Sasha Levin

kbuild: run the checker after the compiler

2021-07-14T14:53:20Z

[ Upstream commit 0c33f125732d0d33392ba6774d85469d565d3496 ] Since the pre-git time the checker is run first, before the compiler. But if the source file contains some syntax error, the warnings from the compiler are more useful than those from sparse (and other checker most probably too). So move the 'check' command to run after the compiler. Signed-off-by: Luc Van Oostenryck Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

kbuild: avoid split lines in .mod files

2020-12-30T10:50:57Z

[ Upstream commit 7d32358be8acb119dcfe39b6cf67ec6d94bf1fe7 ] "xargs echo" is not a safe way to remove line breaks because the input may exceed the command line limit and xargs may break it up into multiple invocations of echo. This should never happen because scripts/gen_autoksyms.sh expects all undefined symbols are placed in the second line of .mod files. One possible way is to replace "xargs echo" with "sed ':x;N;$!bx;s/\n/ /g'" or something, but I rewrote the code by using awk because it is more readable. This issue was reported by Sami Tolvanen; in his Clang LTO patch set, $(multi-used-m) is no longer an ELF object, but a thin archive that contains LLVM bitcode files. llvm-nm prints out symbols for each archive member separately, which results a lot of dupications, in some places, beyond the system-defined limit. This problem must be fixed irrespective of LTO, and we must ensure zero possibility of having this issue. Link: https://lkml.org/lkml/2020/12/1/1658 Reported-by: Sami Tolvanen Signed-off-by: Masahiro Yamada Reviewed-by: Sami Tolvanen Signed-off-by: Sasha Levin

kbuild: remove header compile test

2020-03-05T15:43:47Z

commit fcbb8461fd2376ba3782b5b8bd440c929b8e4980 upstream. There are both positive and negative options about this feature. At first, I thought it was a good idea, but actually Linus stated a negative opinion (https://lkml.org/lkml/2019/9/29/227). I admit it is ugly and annoying. The baseline I'd like to keep is the compile-test of uapi headers. (Otherwise, kernel developers have no way to ensure the correctness of the exported headers.) I will maintain a small build rule in usr/include/Makefile. Remove the other header test functionality. Signed-off-by: Masahiro Yamada [ added to 5.4.y due to start of build warnings from backported patches because of this feature - gregkh] Signed-off-by: Greg Kroah-Hartman

kbuild: remove ar-option and KBUILD_ARFLAGS

2019-10-01T00:20:33Z

Commit 40df759e2b9e ("kbuild: Fix build with binutils <= 2.19") introduced ar-option and KBUILD_ARFLAGS to deal with old binutils. According to Documentation/process/changes.rst, the current minimal supported version of binutils is 2.21 so you can assume the 'D' option is always supported. Not only GNU ar but also llvm-ar supports it. With the 'D' option hard-coded, there is no more user of ar-option or KBUILD_ARFLAGS. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers Tested-by: Nick Desaulniers

kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARN

2019-09-06T14:46:52Z

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 Reviewed-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Reviewed-by: Sedat Dilek

kbuild: move modkern_{c,a}flags to Makefile.lib from Makefile.build

2019-08-21T16:14:11Z

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

kbuild: add CONFIG_ASM_MODVERSIONS

2019-08-21T16:14:11Z

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 Acked-by: Geert Uytterhoeven

kbuild: make single targets work more correctly

2019-08-21T12:05:21Z

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

kbuild: fix modkern_aflags implementation

2019-08-14T17:25:11Z

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