License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
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# SPDX-License-Identifier: GPL-2.0
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2013-02-20 15:32:29 +00:00
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ifneq ($(O),)
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2012-11-05 21:02:08 +00:00
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ifeq ($(origin O), command line)
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2024-02-21 13:42:01 +00:00
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$(if $(shell cd $(PWD); test -d $(O) || echo $(O)),$(error O=$(O) does not exist),)
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2020-03-06 18:32:58 +00:00
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ABSOLUTE_O := $(shell cd $(PWD); cd $(O) ; pwd)
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2012-11-05 21:02:08 +00:00
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OUTPUT := $(ABSOLUTE_O)/$(if $(subdir),$(subdir)/)
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2012-08-13 14:23:02 +00:00
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COMMAND_O := O=$(ABSOLUTE_O)
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2012-11-05 21:02:08 +00:00
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ifeq ($(objtree),)
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objtree := $(O)
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endif
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2012-04-11 16:36:14 +00:00
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endif
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2013-02-20 15:32:29 +00:00
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endif
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2012-04-11 16:36:14 +00:00
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# check that the output directory actually exists
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2013-02-20 15:32:29 +00:00
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ifneq ($(OUTPUT),)
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2017-11-05 09:44:16 +00:00
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OUTDIR := $(shell cd $(OUTPUT) && pwd)
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2012-04-11 16:36:14 +00:00
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$(if $(OUTDIR),, $(error output directory "$(OUTPUT)" does not exist))
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endif
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#
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# Include saner warnings here, which can catch bugs:
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#
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2012-04-11 16:36:15 +00:00
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EXTRA_WARNINGS := -Wbad-function-cast
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EXTRA_WARNINGS += -Wdeclaration-after-statement
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EXTRA_WARNINGS += -Wformat-security
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EXTRA_WARNINGS += -Wformat-y2k
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EXTRA_WARNINGS += -Winit-self
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EXTRA_WARNINGS += -Wmissing-declarations
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EXTRA_WARNINGS += -Wmissing-prototypes
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EXTRA_WARNINGS += -Wnested-externs
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EXTRA_WARNINGS += -Wno-system-headers
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EXTRA_WARNINGS += -Wold-style-definition
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EXTRA_WARNINGS += -Wpacked
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EXTRA_WARNINGS += -Wredundant-decls
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EXTRA_WARNINGS += -Wstrict-prototypes
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EXTRA_WARNINGS += -Wswitch-default
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EXTRA_WARNINGS += -Wswitch-enum
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EXTRA_WARNINGS += -Wundef
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EXTRA_WARNINGS += -Wwrite-strings
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EXTRA_WARNINGS += -Wformat
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2021-05-07 01:02:42 +00:00
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EXTRA_WARNINGS += -Wno-type-limits
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2012-04-11 16:36:14 +00:00
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2018-02-21 22:45:12 +00:00
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# Makefiles suck: This macro sets a default value of $(2) for the
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# variable named by $(1), unless the variable has been set by
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# environment or command line. This is necessary for CC and AR
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# because make sets default values, so the simpler ?= approach
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# won't work as expected.
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define allow-override
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$(if $(or $(findstring environment,$(origin $(1))),\
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$(findstring command line,$(origin $(1)))),,\
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$(eval $(1) = $(2)))
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endef
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|
2021-04-13 15:34:19 +00:00
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ifneq ($(LLVM),)
|
kbuild: Make $(LLVM) more flexible
The LLVM make variable allows a developer to quickly switch between the
GNU and LLVM tools. However, it does not handle versioned binaries, such
as the ones shipped by Debian, as LLVM=1 just defines the tool variables
with the unversioned binaries.
There was some discussion during the review of the patch that introduces
LLVM=1 around versioned binaries, ultimately coming to the conclusion
that developers can just add the folder that contains the unversioned
binaries to their PATH, as Debian's versioned suffixed binaries are
really just symlinks to the unversioned binaries in /usr/lib/llvm-#/bin:
$ realpath /usr/bin/clang-14
/usr/lib/llvm-14/bin/clang
$ PATH=/usr/lib/llvm-14/bin:$PATH make ... LLVM=1
However, that can be cumbersome to developers who are constantly testing
series with different toolchains and versions. It is simple enough to
support these versioned binaries directly in the Kbuild system by
allowing the developer to specify the version suffix with LLVM=, which
is shorter than the above suggestion:
$ make ... LLVM=-14
It does not change the meaning of LLVM=1 (which will continue to use
unversioned binaries) and it does not add too much additional complexity
to the existing $(LLVM) code, while allowing developers to quickly test
their series with different versions of the whole LLVM suite of tools.
Some developers may build LLVM from source but not add the binaries to
their PATH, as they may not want to use that toolchain systemwide.
Support those developers by allowing them to supply the directory that
the LLVM tools are available in, as it is no more complex to support
than the version suffix change above.
$ make ... LLVM=/path/to/llvm/
Update and reorder the documentation to reflect these new additions.
At the same time, notate that LLVM=0 is not the same as just omitting it
altogether, which has confused people in the past.
Link: https://lore.kernel.org/r/20200317215515.226917-1-ndesaulniers@google.com/
Link: https://lore.kernel.org/r/20220224151322.072632223@infradead.org/
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-03-04 17:08:14 +00:00
|
|
|
ifneq ($(filter %/,$(LLVM)),)
|
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|
|
LLVM_PREFIX := $(LLVM)
|
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|
|
|
else ifneq ($(filter -%,$(LLVM)),)
|
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|
LLVM_SUFFIX := $(LLVM)
|
|
|
|
|
endif
|
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$(call allow-override,CC,$(LLVM_PREFIX)clang$(LLVM_SUFFIX))
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|
|
$(call allow-override,AR,$(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX))
|
|
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|
|
$(call allow-override,LD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX))
|
|
|
|
|
$(call allow-override,CXX,$(LLVM_PREFIX)clang++$(LLVM_SUFFIX))
|
|
|
|
|
$(call allow-override,STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX))
|
2021-04-13 15:34:19 +00:00
|
|
|
else
|
2018-02-21 22:45:12 +00:00
|
|
|
# Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
|
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$(call allow-override,CC,$(CROSS_COMPILE)gcc)
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$(call allow-override,AR,$(CROSS_COMPILE)ar)
|
|
|
|
|
$(call allow-override,LD,$(CROSS_COMPILE)ld)
|
|
|
|
|
$(call allow-override,CXX,$(CROSS_COMPILE)g++)
|
|
|
|
|
$(call allow-override,STRIP,$(CROSS_COMPILE)strip)
|
2021-04-13 15:34:19 +00:00
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
|
2018-02-21 22:45:12 +00:00
|
|
|
|
2020-11-10 16:43:05 +00:00
|
|
|
ifneq ($(LLVM),)
|
kbuild: Make $(LLVM) more flexible
The LLVM make variable allows a developer to quickly switch between the
GNU and LLVM tools. However, it does not handle versioned binaries, such
as the ones shipped by Debian, as LLVM=1 just defines the tool variables
with the unversioned binaries.
There was some discussion during the review of the patch that introduces
LLVM=1 around versioned binaries, ultimately coming to the conclusion
that developers can just add the folder that contains the unversioned
binaries to their PATH, as Debian's versioned suffixed binaries are
really just symlinks to the unversioned binaries in /usr/lib/llvm-#/bin:
$ realpath /usr/bin/clang-14
/usr/lib/llvm-14/bin/clang
$ PATH=/usr/lib/llvm-14/bin:$PATH make ... LLVM=1
However, that can be cumbersome to developers who are constantly testing
series with different toolchains and versions. It is simple enough to
support these versioned binaries directly in the Kbuild system by
allowing the developer to specify the version suffix with LLVM=, which
is shorter than the above suggestion:
$ make ... LLVM=-14
It does not change the meaning of LLVM=1 (which will continue to use
unversioned binaries) and it does not add too much additional complexity
to the existing $(LLVM) code, while allowing developers to quickly test
their series with different versions of the whole LLVM suite of tools.
Some developers may build LLVM from source but not add the binaries to
their PATH, as they may not want to use that toolchain systemwide.
Support those developers by allowing them to supply the directory that
the LLVM tools are available in, as it is no more complex to support
than the version suffix change above.
$ make ... LLVM=/path/to/llvm/
Update and reorder the documentation to reflect these new additions.
At the same time, notate that LLVM=0 is not the same as just omitting it
altogether, which has confused people in the past.
Link: https://lore.kernel.org/r/20200317215515.226917-1-ndesaulniers@google.com/
Link: https://lore.kernel.org/r/20220224151322.072632223@infradead.org/
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-03-04 17:08:14 +00:00
|
|
|
HOSTAR ?= $(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)
|
|
|
|
|
HOSTCC ?= $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
|
|
|
|
|
HOSTLD ?= $(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)
|
2020-11-10 16:43:05 +00:00
|
|
|
else
|
|
|
|
|
HOSTAR ?= ar
|
|
|
|
|
HOSTCC ?= gcc
|
|
|
|
|
HOSTLD ?= ld
|
|
|
|
|
endif
|
|
|
|
|
|
2021-01-28 01:50:58 +00:00
|
|
|
# Some tools require Clang, LLC and/or LLVM utils
|
|
|
|
|
CLANG ?= clang
|
|
|
|
|
LLC ?= llc
|
|
|
|
|
LLVM_CONFIG ?= llvm-config
|
|
|
|
|
LLVM_OBJCOPY ?= llvm-objcopy
|
|
|
|
|
LLVM_STRIP ?= llvm-strip
|
|
|
|
|
|
2017-08-27 07:54:40 +00:00
|
|
|
ifeq ($(CC_NO_CLANG), 1)
|
2017-02-14 13:34:35 +00:00
|
|
|
EXTRA_WARNINGS += -Wstrict-aliasing=3
|
tools: Help cross-building with clang
Cross-compilation with clang uses the -target parameter rather than a
toolchain prefix. Just like the kernel Makefile, add that parameter to
CFLAGS when CROSS_COMPILE is set.
Unlike the kernel Makefile, we use the --sysroot and --gcc-toolchain
options because unlike the kernel, tools require standard libraries.
Commit c91d4e47e10e ("Makefile: Remove '--gcc-toolchain' flag") provides
some background about --gcc-toolchain. Normally clang finds on its own
the additional utilities and libraries that it needs (for example GNU ld
or glibc). On some systems however, this autodetection doesn't work.
There, our only recourse is asking GCC directly, and pass the result to
--sysroot and --gcc-toolchain. Of course that only works when a cross
GCC is available.
Autodetection worked fine on Debian, but to use the aarch64-linux-gnu
toolchain from Archlinux I needed both --sysroot (for crt1.o) and
--gcc-toolchain (for crtbegin.o, -lgcc). The --prefix parameter wasn't
needed there, but it might be useful on other distributions.
Use the CLANG_CROSS_FLAGS variable instead of CLANG_FLAGS because it
allows tools such as bpftool, that need to build both host and target
binaries, to easily filter out the cross-build flags from CFLAGS.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/bpf/20211216163842.829836-2-jean-philippe@linaro.org
2021-12-16 16:38:38 +00:00
|
|
|
|
|
|
|
|
else ifneq ($(CROSS_COMPILE),)
|
2022-03-08 12:14:28 +00:00
|
|
|
# Allow userspace to override CLANG_CROSS_FLAGS to specify their own
|
|
|
|
|
# sysroots and flags or to avoid the GCC call in pure Clang builds.
|
|
|
|
|
ifeq ($(CLANG_CROSS_FLAGS),)
|
tools: Help cross-building with clang
Cross-compilation with clang uses the -target parameter rather than a
toolchain prefix. Just like the kernel Makefile, add that parameter to
CFLAGS when CROSS_COMPILE is set.
Unlike the kernel Makefile, we use the --sysroot and --gcc-toolchain
options because unlike the kernel, tools require standard libraries.
Commit c91d4e47e10e ("Makefile: Remove '--gcc-toolchain' flag") provides
some background about --gcc-toolchain. Normally clang finds on its own
the additional utilities and libraries that it needs (for example GNU ld
or glibc). On some systems however, this autodetection doesn't work.
There, our only recourse is asking GCC directly, and pass the result to
--sysroot and --gcc-toolchain. Of course that only works when a cross
GCC is available.
Autodetection worked fine on Debian, but to use the aarch64-linux-gnu
toolchain from Archlinux I needed both --sysroot (for crt1.o) and
--gcc-toolchain (for crtbegin.o, -lgcc). The --prefix parameter wasn't
needed there, but it might be useful on other distributions.
Use the CLANG_CROSS_FLAGS variable instead of CLANG_FLAGS because it
allows tools such as bpftool, that need to build both host and target
binaries, to easily filter out the cross-build flags from CFLAGS.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/bpf/20211216163842.829836-2-jean-philippe@linaro.org
2021-12-16 16:38:38 +00:00
|
|
|
CLANG_CROSS_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%))
|
2022-02-01 09:31:20 +00:00
|
|
|
GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)gcc 2>/dev/null))
|
tools: Help cross-building with clang
Cross-compilation with clang uses the -target parameter rather than a
toolchain prefix. Just like the kernel Makefile, add that parameter to
CFLAGS when CROSS_COMPILE is set.
Unlike the kernel Makefile, we use the --sysroot and --gcc-toolchain
options because unlike the kernel, tools require standard libraries.
Commit c91d4e47e10e ("Makefile: Remove '--gcc-toolchain' flag") provides
some background about --gcc-toolchain. Normally clang finds on its own
the additional utilities and libraries that it needs (for example GNU ld
or glibc). On some systems however, this autodetection doesn't work.
There, our only recourse is asking GCC directly, and pass the result to
--sysroot and --gcc-toolchain. Of course that only works when a cross
GCC is available.
Autodetection worked fine on Debian, but to use the aarch64-linux-gnu
toolchain from Archlinux I needed both --sysroot (for crt1.o) and
--gcc-toolchain (for crtbegin.o, -lgcc). The --prefix parameter wasn't
needed there, but it might be useful on other distributions.
Use the CLANG_CROSS_FLAGS variable instead of CLANG_FLAGS because it
allows tools such as bpftool, that need to build both host and target
binaries, to easily filter out the cross-build flags from CFLAGS.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/bpf/20211216163842.829836-2-jean-philippe@linaro.org
2021-12-16 16:38:38 +00:00
|
|
|
ifneq ($(GCC_TOOLCHAIN_DIR),)
|
|
|
|
|
CLANG_CROSS_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
|
|
|
|
|
CLANG_CROSS_FLAGS += --sysroot=$(shell $(CROSS_COMPILE)gcc -print-sysroot)
|
|
|
|
|
CLANG_CROSS_FLAGS += --gcc-toolchain=$(realpath $(GCC_TOOLCHAIN_DIR)/..)
|
|
|
|
|
endif # GCC_TOOLCHAIN_DIR
|
2022-03-08 12:14:28 +00:00
|
|
|
endif # CLANG_CROSS_FLAGS
|
tools: Help cross-building with clang
Cross-compilation with clang uses the -target parameter rather than a
toolchain prefix. Just like the kernel Makefile, add that parameter to
CFLAGS when CROSS_COMPILE is set.
Unlike the kernel Makefile, we use the --sysroot and --gcc-toolchain
options because unlike the kernel, tools require standard libraries.
Commit c91d4e47e10e ("Makefile: Remove '--gcc-toolchain' flag") provides
some background about --gcc-toolchain. Normally clang finds on its own
the additional utilities and libraries that it needs (for example GNU ld
or glibc). On some systems however, this autodetection doesn't work.
There, our only recourse is asking GCC directly, and pass the result to
--sysroot and --gcc-toolchain. Of course that only works when a cross
GCC is available.
Autodetection worked fine on Debian, but to use the aarch64-linux-gnu
toolchain from Archlinux I needed both --sysroot (for crt1.o) and
--gcc-toolchain (for crtbegin.o, -lgcc). The --prefix parameter wasn't
needed there, but it might be useful on other distributions.
Use the CLANG_CROSS_FLAGS variable instead of CLANG_FLAGS because it
allows tools such as bpftool, that need to build both host and target
binaries, to easily filter out the cross-build flags from CFLAGS.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/bpf/20211216163842.829836-2-jean-philippe@linaro.org
2021-12-16 16:38:38 +00:00
|
|
|
CFLAGS += $(CLANG_CROSS_FLAGS)
|
|
|
|
|
AFLAGS += $(CLANG_CROSS_FLAGS)
|
2023-02-17 15:18:32 +00:00
|
|
|
else
|
|
|
|
|
CLANG_CROSS_FLAGS :=
|
tools: Help cross-building with clang
Cross-compilation with clang uses the -target parameter rather than a
toolchain prefix. Just like the kernel Makefile, add that parameter to
CFLAGS when CROSS_COMPILE is set.
Unlike the kernel Makefile, we use the --sysroot and --gcc-toolchain
options because unlike the kernel, tools require standard libraries.
Commit c91d4e47e10e ("Makefile: Remove '--gcc-toolchain' flag") provides
some background about --gcc-toolchain. Normally clang finds on its own
the additional utilities and libraries that it needs (for example GNU ld
or glibc). On some systems however, this autodetection doesn't work.
There, our only recourse is asking GCC directly, and pass the result to
--sysroot and --gcc-toolchain. Of course that only works when a cross
GCC is available.
Autodetection worked fine on Debian, but to use the aarch64-linux-gnu
toolchain from Archlinux I needed both --sysroot (for crt1.o) and
--gcc-toolchain (for crtbegin.o, -lgcc). The --prefix parameter wasn't
needed there, but it might be useful on other distributions.
Use the CLANG_CROSS_FLAGS variable instead of CLANG_FLAGS because it
allows tools such as bpftool, that need to build both host and target
binaries, to easily filter out the cross-build flags from CFLAGS.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/bpf/20211216163842.829836-2-jean-philippe@linaro.org
2021-12-16 16:38:38 +00:00
|
|
|
endif # CROSS_COMPILE
|
2017-02-14 13:34:35 +00:00
|
|
|
|
2017-02-22 19:54:53 +00:00
|
|
|
# Hack to avoid type-punned warnings on old systems such as RHEL5:
|
|
|
|
|
# We should be changing CFLAGS and checking gcc version, but this
|
|
|
|
|
# will do for now and keep the above -Wstrict-aliasing=3 in place
|
|
|
|
|
# in newer systems.
|
|
|
|
|
# Needed for the __raw_cmpxchg in tools/arch/x86/include/asm/cmpxchg.h
|
2019-07-19 18:34:30 +00:00
|
|
|
#
|
2021-02-10 23:40:05 +00:00
|
|
|
# See https://lore.kernel.org/lkml/9a8748490611281710g78402fbeh8ff7fcc162dbcbca@mail.gmail.com/
|
|
|
|
|
# and https://gcc.gnu.org/gcc-4.8/changes.html,
|
2019-07-19 18:34:30 +00:00
|
|
|
# that takes into account Linus's comments (search for Wshadow) for the reasoning about
|
|
|
|
|
# -Wshadow not being interesting before gcc 4.8.
|
|
|
|
|
|
2017-02-22 19:54:53 +00:00
|
|
|
ifneq ($(filter 3.%,$(MAKE_VERSION)),) # make-3
|
|
|
|
|
EXTRA_WARNINGS += -fno-strict-aliasing
|
2019-07-19 18:34:30 +00:00
|
|
|
EXTRA_WARNINGS += -Wno-shadow
|
|
|
|
|
else
|
|
|
|
|
EXTRA_WARNINGS += -Wshadow
|
2017-02-22 19:54:53 +00:00
|
|
|
endif
|
|
|
|
|
|
2012-04-11 16:36:14 +00:00
|
|
|
ifneq ($(findstring $(MAKEFLAGS), w),w)
|
|
|
|
|
PRINT_DIR = --no-print-directory
|
|
|
|
|
else
|
|
|
|
|
NO_SUBDIR = :
|
|
|
|
|
endif
|
|
|
|
|
|
2023-10-08 21:22:51 +00:00
|
|
|
# If the user is running make -s (silent mode), suppress echoing of commands
|
|
|
|
|
# make-4.0 (and later) keep single letter options in the 1st word of MAKEFLAGS.
|
|
|
|
|
ifeq ($(filter 3.%,$(MAKE_VERSION)),)
|
|
|
|
|
short-opts := $(firstword -$(MAKEFLAGS))
|
|
|
|
|
else
|
|
|
|
|
short-opts := $(filter-out --%,$(MAKEFLAGS))
|
|
|
|
|
endif
|
|
|
|
|
|
|
|
|
|
ifneq ($(findstring s,$(short-opts)),)
|
2017-01-19 04:16:55 +00:00
|
|
|
silent=1
|
|
|
|
|
endif
|
|
|
|
|
|
2012-11-05 15:15:24 +00:00
|
|
|
#
|
|
|
|
|
# Define a callable command for descending to a new directory
|
|
|
|
|
#
|
|
|
|
|
# Call by doing: $(call descend,directory[,target])
|
|
|
|
|
#
|
|
|
|
|
descend = \
|
2012-11-05 21:02:08 +00:00
|
|
|
+mkdir -p $(OUTPUT)$(1) && \
|
2012-11-13 17:14:38 +00:00
|
|
|
$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
|
2012-11-05 15:15:24 +00:00
|
|
|
|
2012-11-05 21:02:08 +00:00
|
|
|
QUIET_SUBDIR0 = +$(MAKE) $(COMMAND_O) -C # space to separate -C and subdir
|
2012-04-11 16:36:14 +00:00
|
|
|
QUIET_SUBDIR1 =
|
|
|
|
|
|
2017-01-19 04:16:55 +00:00
|
|
|
ifneq ($(silent),1)
|
2013-10-09 09:49:27 +00:00
|
|
|
ifneq ($(V),1)
|
2021-04-21 18:58:48 +00:00
|
|
|
QUIET_CC = @echo ' CC '$@;
|
|
|
|
|
QUIET_CC_FPIC = @echo ' CC FPIC '$@;
|
|
|
|
|
QUIET_CLANG = @echo ' CLANG '$@;
|
|
|
|
|
QUIET_AR = @echo ' AR '$@;
|
|
|
|
|
QUIET_LINK = @echo ' LINK '$@;
|
|
|
|
|
QUIET_MKDIR = @echo ' MKDIR '$@;
|
|
|
|
|
QUIET_GEN = @echo ' GEN '$@;
|
2012-04-11 16:36:14 +00:00
|
|
|
QUIET_SUBDIR0 = +@subdir=
|
2013-10-09 09:49:27 +00:00
|
|
|
QUIET_SUBDIR1 = ;$(NO_SUBDIR) \
|
2021-04-21 18:58:48 +00:00
|
|
|
echo ' SUBDIR '$$subdir; \
|
2012-04-11 16:36:14 +00:00
|
|
|
$(MAKE) $(PRINT_DIR) -C $$subdir
|
2021-04-21 18:58:48 +00:00
|
|
|
QUIET_FLEX = @echo ' FLEX '$@;
|
|
|
|
|
QUIET_BISON = @echo ' BISON '$@;
|
|
|
|
|
QUIET_GENSKEL = @echo ' GENSKEL '$@;
|
2012-11-05 21:02:08 +00:00
|
|
|
|
|
|
|
|
descend = \
|
2021-04-21 18:58:48 +00:00
|
|
|
+@echo ' DESCEND '$(1); \
|
2012-11-05 21:02:08 +00:00
|
|
|
mkdir -p $(OUTPUT)$(1) && \
|
2012-11-13 17:14:38 +00:00
|
|
|
$(MAKE) $(COMMAND_O) subdir=$(if $(subdir),$(subdir)/$(1),$(1)) $(PRINT_DIR) -C $(1) $(2)
|
2013-12-19 13:42:00 +00:00
|
|
|
|
2021-04-21 18:58:48 +00:00
|
|
|
QUIET_CLEAN = @printf ' CLEAN %s\n' $1;
|
|
|
|
|
QUIET_INSTALL = @printf ' INSTALL %s\n' $1;
|
|
|
|
|
QUIET_UNINST = @printf ' UNINST %s\n' $1;
|
2013-10-09 09:49:27 +00:00
|
|
|
endif
|
2012-04-11 16:36:14 +00:00
|
|
|
endif
|
Kbuild: fix # escaping in .cmd files for future Make
I tried building using a freshly built Make (4.2.1-69-g8a731d1), but
already the objtool build broke with
orc_dump.c: In function ‘orc_dump’:
orc_dump.c:106:2: error: ‘elf_getshnum’ is deprecated [-Werror=deprecated-declarations]
if (elf_getshdrnum(elf, &nr_sections)) {
Turns out that with that new Make, the backslash was not removed, so cpp
didn't see a #include directive, grep found nothing, and
-DLIBELF_USE_DEPRECATED was wrongly put in CFLAGS.
Now, that new Make behaviour is documented in their NEWS file:
* WARNING: Backward-incompatibility!
Number signs (#) appearing inside a macro reference or function invocation
no longer introduce comments and should not be escaped with backslashes:
thus a call such as:
foo := $(shell echo '#')
is legal. Previously the number sign needed to be escaped, for example:
foo := $(shell echo '\#')
Now this latter will resolve to "\#". If you want to write makefiles
portable to both versions, assign the number sign to a variable:
C := \#
foo := $(shell echo '$C')
This was claimed to be fixed in 3.81, but wasn't, for some reason.
To detect this change search for 'nocomment' in the .FEATURES variable.
This also fixes up the two make-cmd instances to replace # with $(pound)
rather than with \#. There might very well be other places that need
similar fixup in preparation for whatever future Make release contains
the above change, but at least this builds an x86_64 defconfig with the
new make.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197847
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-04-08 21:35:28 +00:00
|
|
|
|
|
|
|
|
pound := \#
|