24 Feb, 2020
1 commit
-
[ Upstream commit 88fe89a47153facd8cb2d06d5c8727f7224c43c2 ]
Bartosz Golaszewski reports that when "make {menu,n,g,x}config" fails
due to missing packages, a temporary file is left over, which is not
ignored by git.For example, if GTK+ is not installed:
$ make gconfig
*
* Unable to find the GTK+ installation. Please make sure that
* the GTK+ 2.0 development package is correctly installed.
* You need gtk+-2.0 gmodule-2.0 libglade-2.0
*
scripts/kconfig/Makefile:208: recipe for target 'scripts/kconfig/gconf-cfg' failed
make[1]: *** [scripts/kconfig/gconf-cfg] Error 1
Makefile:567: recipe for target 'gconfig' failed
make: *** [gconfig] Error 2
$ git status
HEAD detached at v5.4
Untracked files:
(use "git add ..." to include in what will be committed)scripts/kconfig/gconf-cfg.tmp
nothing added to commit but untracked files present (use "git add" to track)
This is because the check scripts are run with filechk, which misses
to clean up the temporary file on failure.When the line
{ $(filechk_$(1)); } > $@.tmp;
... fails, it exits immediately due to the 'set -e'. Use trap to make
sure to delete the temporary file on exit.For extra safety, I replaced $@.tmp with $(dot-target).tmp to make it
a hidden file.Reported-by: Bartosz Golaszewski
Signed-off-by: Masahiro Yamada
Signed-off-by: Sasha Levin
01 Oct, 2019
1 commit
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Commit 40df759e2b9e ("kbuild: Fix build with binutils
Reviewed-by: Nick Desaulniers
Tested-by: Nick Desaulniers
27 Jul, 2019
1 commit
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Commit 415008af3219 ("docs-rst: convert lsm from DocBook to ReST")
removed the last users of this macro.Signed-off-by: Masahiro Yamada
17 Jul, 2019
1 commit
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We can re-add this whenever it is needed. At this moment, it is unused.
Signed-off-by: Masahiro Yamada
13 Jul, 2019
1 commit
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Pull Kbuild updates from Masahiro Yamada:
- remove headers_{install,check}_all targets
- remove unreasonable 'depends on !UML' from CONFIG_SAMPLES
- re-implement 'make headers_install' more cleanly
- add new header-test-y syntax to compile-test headers
- compile-test exported headers to ensure they are compilable in
user-space- compile-test headers under include/ to ensure they are self-contained
- remove -Waggregate-return, -Wno-uninitialized, -Wno-unused-value
flags- add -Werror=unknown-warning-option for Clang
- add 128-bit built-in types support to genksyms
- fix missed rebuild of modules.builtin
- propagate 'No space left on device' error in fixdep to Make
- allow Clang to use its integrated assembler
- improve some coccinelle scripts
- add a new flag KBUILD_ABS_SRCTREE to request Kbuild to use absolute
path for $(srctree).- do not ignore errors when compression utility is missing
- misc cleanups
* tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (49 commits)
kbuild: use -- separater intead of $(filter-out ...) for cc-cross-prefix
kbuild: Inform user to pass ARCH= for make mrproper
kbuild: fix compression errors getting ignored
kbuild: add a flag to force absolute path for srctree
kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctree
kbuild: remove src and obj from the top Makefile
scripts/tags.sh: remove unused environment variables from comments
scripts/tags.sh: drop SUBARCH support for ARM
kbuild: compile-test kernel headers to ensure they are self-contained
kheaders: include only headers into kheaders_data.tar.xz
kheaders: remove meaningless -R option of 'ls'
kbuild: support header-test-pattern-y
kbuild: do not create wrappers for header-test-y
kbuild: compile-test exported headers to ensure they are self-contained
init/Kconfig: add CONFIG_CC_CAN_LINK
kallsyms: exclude kasan local symbols on s390
kbuild: add more hints about SUBDIRS replacement
coccinelle: api/stream_open: treat all wait_.*() calls as blocking
coccinelle: put_device: Add a cast to an expression for an assignment
coccinelle: put_device: Adjust a message construction
...
11 Jul, 2019
1 commit
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arch/mips/Makefile passes prefixes that start with '-' to cc-cross-prefix
when $(tool-archpref) evaluates to the empty string.They are filtered-out before the $(shell ...) invocation. Otherwise,
'command -v' would be confused.$ command -v -linux-gcc
bash: command: -l: invalid option
command: usage: command [-pVv] command [arg ...]Since commit 913ab9780fc0 ("kbuild: use more portable 'command -v' for
cc-cross-prefix"), cc-cross-prefix throws away the stderr output, so
the console is not polluted in any way.This is not a big deal in practice, but I see a slightly better taste
in adding '--' to teach it that '-linux-gcc' is an argument instead of
a command option.This will cause extra forking of subshell, but it will not be noticeable
performance regression.Signed-off-by: Masahiro Yamada
01 Jul, 2019
3 commits
-
The string returned by $(filter-out ...) does not contain any leading
or trailing spaces.With the previous commit, 'any-prereq' no longer contains any
excessive spaces.Nor does 'cmd-check' since it expands to a $(filter-out ...) call.
So, only the space that matters is the one between 'any-prereq'
and 'cmd-check'.By removing it from the code, we can save $(strip ...) evaluation.
This refactoring is possible because $(any-prereq)$(cmd-check) is only
passed to the first argument of $(if ...), so we are only interested
in whether or not it is empty.Signed-off-by: Masahiro Yamada
-
The string returned by $(filter-out ...) does not contain any leading
or trailing spaces.So, only the space that matters is the one between
$(filter-out $(PHONY),$?)
and
$(filter-out $(PHONY) $(wildcard $^),$^)
By removing it from the code, we can save $(strip ...) evaluation.
This refactoring is possible because $(any-prereq) is only passed to
the first argument of $(if ...), so we are only interested in whether
or not it is empty.This is also the prerequisite for the next commit.
Signed-off-by: Masahiro Yamada
-
I prefer 'cmd-check' for consistency.
We have 'echo-cmd', 'cmd', 'cmd_and_fixdep', etc. in this file.
Signed-off-by: Masahiro Yamada
15 Jun, 2019
2 commits
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Now that hdr-inst is used only in the top Makefile, move it there
from scripts/Kbuild.include.Signed-off-by: Masahiro Yamada
-
The kbuild documentation clearly shows that the documents
there are written at different times: some use markdown,
some use their own peculiar logic to split sections.Convert everything to ReST without affecting too much
the author's style and avoiding adding uneeded markups.The conversion is actually:
- add blank lines and identation in order to identify paragraphs;
- fix tables markups;
- add some lists markups;
- mark literal blocks;
- adjust title markups.At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.Signed-off-by: Mauro Carvalho Chehab
Signed-off-by: Jonathan Corbet
07 Jun, 2019
1 commit
-
To print the pathname that will be used by shell in the current
environment, 'command -v' is a standardized way. [1]'which' is also often used in scripts, but it is less portable.
When I worked on commit bd55f96fa9fc ("kbuild: refactor cc-cross-prefix
implementation"), I was eager to use 'command -v' but it did not work.
(The reason is explained below.)I kept 'which' as before but got rid of '> /dev/null 2>&1' as I
thought it was no longer needed. Sorry, I was wrong.It works well on my Ubuntu machine, but Alexey Brodkin reports noisy
warnings on CentOS7 when 'which' fails to find the given command in
the PATH environment.$ which foo
which: no foo in (/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin)Given that behavior of 'which' depends on system (and it may not be
installed by default), I want to try 'command -v' once again.The specification [1] clearly describes the behavior of 'command -v'
when the given command is not found:Otherwise, no output shall be written and the exit status shall reflect
that the name was not found.However, we need a little magic to use 'command -v' from Make.
$(shell ...) passes the argument to a subshell for execution, and
returns the standard output of the command.Here is a trick. GNU Make may optimize this by executing the command
directly instead of forking a subshell, if no shell special characters
are found in the command and omitting the subshell will not change the
behavior.In this case, no shell special character is used. So, Make will try
to run it directly. However, 'command' is a shell-builtin command,
then Make would fail to find it in the PATH environment:$ make ARCH=m68k defconfig
make: command: Command not found
make: command: Command not found
make: command: Command not foundIn fact, Make has a table of shell-builtin commands because it must
ask the shell to execute them.Until recently, 'command' was missing in the table.
This issue was fixed by the following commit:
| commit 1af314465e5dfe3e8baa839a32a72e83c04f26ef
| Author: Paul Smith
| Date: Sun Nov 12 18:10:28 2017 -0500
|
| * job.c: Add "command" as a known shell built-in.
|
| This is not a POSIX shell built-in but it's common in UNIX shells.
| Reported by Nick Bowler .Because the latest release is GNU Make 4.2.1 in 2016, this commit is
not included in any released versions. (But some distributions may
have back-ported it.)We need to trick Make to spawn a subshell. There are various ways to
do so:1) Use a shell special character '~' as dummy
$(shell : ~; command -v $(c)gcc)
2) Use a variable reference that always expands to the empty string
(suggested by David Laight)$(shell command$${x:+} -v $(c)gcc)
3) Use redirect
$(shell command -v $(c)gcc 2>/dev/null)
I chose 3) to not confuse people. The stderr would not be polluted
anyway, but it will provide extra safety, and is easy to understand.Tested on Make 3.81, 3.82, 4.0, 4.1, 4.2, 4.2.1
[1] http://pubs.opengroup.org/onlinepubs/9699919799/utilities/command.html
Fixes: bd55f96fa9fc ("kbuild: refactor cc-cross-prefix implementation")
Cc: linux-stable # 5.1
Reported-by: Alexey Brodkin
Signed-off-by: Masahiro Yamada
Tested-by: Alexey Brodkin
31 May, 2019
1 commit
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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
Reported-by: Masahiro Yamada
Signed-off-by: Greg Kroah-Hartman
Reviewed-by: Kate Stewart
Signed-off-by: Greg Kroah-Hartman
20 May, 2019
1 commit
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If you want to see if your linker supports a certain flag, then ask the
linker directly with ld-option (not the compiler with cc-ldoption).
Checking for linker flag support is an antipattern that complicates the
usage of various linkers other than bfd via -fuse-ld={bfd|gold|lld}.Cc: clang-built-linux@googlegroups.com
Suggested-by: Masahiro Yamada
Signed-off-by: Nick Desaulniers
Signed-off-by: Masahiro Yamada
18 May, 2019
1 commit
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The 'addtree' and 'flags' in scripts/Kbuild.include are so compilecated
and ugly.As I mentioned in [1], Kbuild should stop automatic prefixing of header
search path options.I fixed up (almost) all Makefiles in the kernel. Now 'addtree' and
'flags' have been removed.Kbuild still caters to add $(srctree)/$(src) and $(objtree)/$(obj)
to the header search path for O= building, but never touches extra
compiler options from ccflags-y etc.[1]: https://patchwork.kernel.org/patch/9632347/
Signed-off-by: Masahiro Yamada
04 Mar, 2019
1 commit
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There is no more direct user of this macro; it is only used by
cc-ifversion.Calling this macro is not efficient since it invokes the compiler to
get the compiler version. CONFIG_GCC_VERSION is already calculated in
the Kconfig stage, so Makefile can reuse it.Here is a note about the slight difference between cc-version and
CONFIG_GCC_VERSION:When using Clang, cc-version is evaluated to '0402' because Clang
defines __GNUC__ and __GNUC__MINOR__, and looks like GCC 4.2 in the
version point of view. On the other hand, CONFIG_GCC_VERSION=0
when $(CC) is clang.There are currently two users of cc-ifversion:
arch/mips/loongson64/Platform
arch/powerpc/MakefileThey are not affected by this change.
The format of cc-version is , while CONFIG_GCC_VERSION
. I adjusted cc-ifversion for the difference of
the number of digits.Signed-off-by: Masahiro Yamada
27 Feb, 2019
1 commit
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- $(word 1, ) is equivalent to $(firstword )
- hardcode "gcc" instead of $(CC)
- minimize the shell script part
A little more notes in case $(filter-out -%, ...) is not clear.
arch/mips/Makefile passes prefixes depending on the configuration.
CROSS_COMPILE := $(call cc-cross-prefix, $(tool-archpref)-linux- \
$(tool-archpref)-linux-gnu- $(tool-archpref)-unknown-linux-gnu-)In the Kconfig stage (e.g. when you run 'make defconfig'), neither
CONFIG_32BIT nor CONFIG_64BIT is defined. So, $(tool-archpref) is
empty. As a result, "-linux -linux-gnu- -unknown-linux-gnu" is passed
into cc-cross-prefix. The command 'which' assumes arguments starting
with a hyphen as command options, then emits the following messages:Illegal option -l
Illegal option -l
Illegal option -uI think it is strange to define CROSS_COMPILE depending on the CONFIG
options since you need to feed $(CC) to Kconfig, but it is how MIPS
Makefile currently works. Anyway, it would not hurt to filter-out
invalid strings beforehand.Signed-off-by: Masahiro Yamada
28 Jan, 2019
1 commit
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In Kbuild, if_changed and friends must have FORCE as a prerequisite.
Hence, $(filter-out FORCE,$^) or $(filter-out $(PHONY),$^) is a common
idiom to get the names of all the prerequisites except phony targets.Add real-prereqs as a shorthand.
Note:
We cannot replace $(filter %.o,$^) in cmd_link_multi-m because $^ may
include auto-generated dependencies from the .*.cmd file when a single
object module is changed into a multi object module. Refer to commit
69ea912fda74 ("kbuild: remove unneeded link_multi_deps"). I added some
comment to avoid accidental breakage.Signed-off-by: Masahiro Yamada
Acked-by: Rob Herring
14 Jan, 2019
1 commit
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Commit eea199b445f6 ("kbuild: remove unnecessary LEX_PREFIX and
YACC_PREFIX") removed the last users of this macro.Signed-off-by: Masahiro Yamada
06 Jan, 2019
2 commits
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You do not have to use define ... endef for filechk_* rules.
For simple cases, the use of assignment looks cleaner, IMHO.
I updated the usage for scripts/Kbuild.include in case somebody
misunderstands the 'define ... endif' is the requirement.Signed-off-by: Masahiro Yamada
Acked-by: Heiko Carstens -
filechk_* rules often consist of multiple 'echo' lines. They must be
surrounded with { } or ( ) to work correctly. Otherwise, only the
string from the last 'echo' would be written into the target.Let's take care of that in the 'filechk' in scripts/Kbuild.include
to clean up filechk_* rules.Signed-off-by: Masahiro Yamada
30 Dec, 2018
1 commit
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Pull Kbuild updates from Masahiro Yamada:
"Kbuild core:
- remove unneeded $(call cc-option,...) switches
- consolidate Clang compiler flags into CLANG_FLAGS
- announce the deprecation of SUBDIRS
- fix single target build for external module
- simplify the dependencies of 'prepare' stage targets
- allow fixdep to directly write to .*.cmd files
- simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS
- change if_changed_rule to accept multi-line recipe
- move .SECONDARY special target to scripts/Kbuild.include
- remove redundant 'set -e'
- improve parallel execution for CONFIG_HEADERS_CHECK
- misc cleanupsTreewide fixes and cleanups
- set Clang flags correctly for PowerPC boot images
- fix UML build error with CONFIG_GCC_PLUGINS
- remove unneeded patterns from .gitignore files
- refactor firmware/Makefile
- remove unneeded rules for *offsets.s
- avoid unneeded regeneration of intermediate .s files
- clean up ./KbuildModpost:
- remove unused -M, -K options
- fix false positive warnings about section mismatch
- use simple devtable lookup instead of linker magic
- misc cleanupsCoccinelle:
- relax boolinit.cocci checks for overall consistency
- fix warning messages of boolinit.cocciOther tools:
- improve -dirty check of scripts/setlocalversion
- add a tool to generate compile_commands.json from .*.cmd files"* tag 'kbuild-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (51 commits)
kbuild: remove unused cmd_gentimeconst
kbuild: remove $(obj)/ prefixes in ./Kbuild
treewide: add intermediate .s files to targets
treewide: remove explicit rules for *offsets.s
firmware: refactor firmware/Makefile
firmware: remove unnecessary patterns from .gitignore
scripts: remove unnecessary ihex2fw and check-lc_ctypes from .gitignore
um: remove unused filechk_gen_header in Makefile
scripts: add a tool to produce a compile_commands.json file
kbuild: add -Werror=implicit-int flag unconditionally
kbuild: add -Werror=strict-prototypes flag unconditionally
kbuild: add -fno-PIE flag unconditionally
scripts: coccinelle: Correct warning message
scripts: coccinelle: only suggest true/false in files that already use them
kbuild: handle part-of-module correctly for *.ll and *.symtypes
kbuild: refactor part-of-module
kbuild: refactor quiet_modtag
kbuild: remove redundant quiet_modtag for $(obj-m)
kbuild: refactor Makefile.asm-generic
user/Makefile: Fix typo and capitalization in comment section
...
19 Dec, 2018
1 commit
-
…k around asm() related GCC inlining bugs"
This reverts commit 77b0bf55bc675233d22cd5df97605d516d64525e.
See this commit for details about the revert:
e769742d3584 ("Revert "x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs"")
Conflicts:
arch/x86/MakefileReported-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Borislav Petkov <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Juergen Gross <jgross@suse.com>
Cc: Richard Biener <rguenther@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
02 Dec, 2018
1 commit
-
In commit 54a702f70589 ("kbuild: mark $(targets) as .SECONDARY and
remove .PRECIOUS markers"), I missed one important feature of the
.SECONDARY target:.SECONDARY with no prerequisites causes all targets to be
treated as secondary.... which agrees with the policy of Kbuild.
Let's move it to scripts/Kbuild.include, with no prerequisites.
Note:
If an intermediate file is generated by $(call if_changed,...), you
still need to add it to "targets" so its .*.cmd file is included.The arm/arm64 crypto files are generated by $(call cmd,shipped),
so they do not need to be added to "targets", but need to be added
to "clean-files" so "make clean" can properly clean them away.Signed-off-by: Masahiro Yamada
01 Dec, 2018
5 commits
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'@set -e; $(echo-cmd) $(cmd_$(1)' can be replaced with '$(cmd)'.
Signed-off-by: Masahiro Yamada
-
With the change of rule_cc_o_c / rule_as_o_S in the last commit, each
command is executed in a separate subshell. Rip off unneeded semicolons.Signed-off-by: Masahiro Yamada
-
The 'define' ... 'endef' directive is useful to confine a series of
shell commands into a single macro:define foo
[action1]
[action2]
[action3]
endifEach action is executed in a separate subshell.
However, rule_cc_o_c and rule_as_o_S in scripts/Makefile.build are
written as follows (with a trailing semicolon in each cmd_*):define rule_cc_o_c
[action1] ; \
[action2] ; \
[action3] ;
endefAll shell commands are concatenated with '; \' so that it looks like
a single command from the Makefile point of view. This does not
exploit the benefits of 'define' ... 'endef' form because a single
shell command can be more simply written, like this:rule_cc_o_c = \
[action1] ; \
[action2] ; \
[action3] ;I guess the intention for the command concatenation was to let the
'@set -e' in if_changed_rule cover all the commands.We can improve the readability by moving '@set -e' to the 'cmd' macro.
The combo of $(call echo-cmd,*) $(cmd_*) in rule_cc_o_c and rule_as_o_S
have been replaced with $(call cmd,*). The trailing back-slashes have
been removed.Here is a note about the performance: the commands in rule_cc_o_c and
rule_as_o_S were previously executed all together in a single subshell,
but now each line in a separate subshell. This means Make will spawn
extra subshells [1]. I measured the build performance for
x86_64_defconfig + CONFIG_MODVERSIONS + CONFIG_TRIM_UNUSED_KSYMS
and I saw slight performance regression, but I believe code readability
and maintainability wins.[1] Precisely, GNU Make may optimize this by executing the command
directly instead of forking a subshell, if no shell special
characters are found in the command line and omitting the subshell
will not change the behavior.Signed-off-by: Masahiro Yamada
-
My main motivation of this commit is to clean up scripts/Kbuild.include
and scripts/Makefile.build.Currently, CONFIG_TRIM_UNUSED_KSYMS works with a tricky gimmick;
possibly exported symbols are detected by letting $(CPP) replace
EXPORT_SYMBOL* with a special string '=== __KSYM_*===', which is
post-processed by sed, and passed to fixdep. The extra preprocessing
is costly, and hacking cmd_and_fixdep is ugly.I came up with a new way to find exported symbols; insert a dummy
symbol __ksym_marker_* to each potentially exported symbol. Those
dummy symbols are picked up by $(NM), post-processed by sed, then
appended to .*.cmd files. I collected the post-process part to a
new shell script scripts/gen_ksymdeps.sh for readability. The dummy
symbols are put into the .discard.* section so that the linker
script rips them off the final vmlinux or modules.A nice side-effect is building with CONFIG_TRIM_UNUSED_KSYMS will
be much faster.Signed-off-by: Masahiro Yamada
Reviewed-by: Nicolas Pitre -
Currently, fixdep writes dependencies to .*.tmp, which is renamed to
.*.cmd after everything succeeds. This is a very safe way to avoid
corrupted .*.cmd files. The if_changed_dep has carried this safety
mechanism since it was added in 2002.If fixdep fails for some reasons or a user terminates the build while
fixdep is running, the incomplete output from the fixdep could be
troublesome.This is my insight about some bad scenarios:
[1] If the compiler succeeds to generate *.o file, but fixdep fails
to write necessary dependencies to .*.cmd file, Make will miss
to rebuild the object when headers or CONFIG options are changed.
In this case, fixdep should not generate .*.cmd file at all so
that 'arg-check' will surely trigger the rebuild of the object.[2] A partially constructed .*.cmd file may not be a syntactically
correct makefile. The next time Make runs, it would include it,
then fail to parse it. Once this happens, 'make clean' is be the
only way to fix it.In fact, [1] is no longer a problem since commit 9c2af1c7377a ("kbuild:
add .DELETE_ON_ERROR special target"). Make deletes a target file on
any failure in its recipe. Because fixdep is a part of the recipe of
*.o target, if it fails, the *.o is deleted anyway. However, I am a
bit worried about the slight possibility of [2].So, here is a solution. Let fixdep directly write to a .*.cmd file,
but allow makefiles to include it only when its corresponding target
exists.This effectively reverts commit 2982c953570b ("kbuild: remove redundant
$(wildcard ...) for cmd_files calculation"), and commit 00d78ab2ba75
("kbuild: remove dead code in cmd_files calculation in top Makefile")
because now we must check the presence of targets.Signed-off-by: Masahiro Yamada
02 Nov, 2018
1 commit
-
There is one more user of $(cc-name) in the top Makefile. It is supposed
to detect Clang before invoking Kconfig, so it should still be there
in the $(shell ...) form. All the other users of $(cc-name) have been
replaced with $(CONFIG_CC_IS_CLANG). Hence, scripts/Kbuild.include does
not need to define cc-name any more.Signed-off-by: Masahiro Yamada
01 Nov, 2018
1 commit
-
The last user of cc-fullversion was removed by commit f2910f0e6835
("powerpc: remove old GCC version checks").Signed-off-by: Masahiro Yamada
29 Oct, 2018
1 commit
-
Pull Kbuild updates from Masahiro Yamada:
- optimize kallsyms slightly
- remove check for old CFLAGS usage
- add some compiler flags unconditionally instead of evaluating
$(call cc-option,...)- fix variable shadowing in host tools
- refactor scripts/mkmakefile
- refactor various makefiles
* tag 'kbuild-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
modpost: Create macro to avoid variable shadowing
ASN.1: Remove unnecessary shadowed local variable
kbuild: use 'else ifeq' for checksrc to improve readability
kbuild: remove unneeded link_multi_deps
kbuild: add -Wno-unused-but-set-variable flag unconditionally
kbuild: add -Wdeclaration-after-statement flag unconditionally
kbuild: add -Wno-pointer-sign flag unconditionally
modpost: remove leftover symbol prefix handling for module device table
kbuild: simplify command line creation in scripts/mkmakefile
kbuild: do not pass $(objtree) to scripts/mkmakefile
kbuild: remove user ID check in scripts/mkmakefile
kbuild: remove VERSION and PATCHLEVEL from $(objtree)/Makefile
kbuild: add --include-dir flag only for out-of-tree build
kbuild: remove dead code in cmd_files calculation in top Makefile
kbuild: hide most of targets when running config or mixed targets
kbuild: remove old check for CFLAGS use
kbuild: prefix Makefile.dtbinst path with $(srctree) unconditionally
kallsyms: remove left-over Blackfin code
kallsyms: reduce size a little on 64-bit
04 Oct, 2018
1 commit
-
… asm() related GCC inlining bugs
Using macros in inline assembly allows us to work around bugs
in GCC's inlining decisions.Compile macros.S and use it to assemble all C files.
Currently only x86 will use it.Background:
The inlining pass of GCC doesn't include an assembler, so it's not aware
of basic properties of the generated code, such as its size in bytes,
or that there are such things as discontiuous blocks of code and data
due to the newfangled linker feature called 'sections' ...Instead GCC uses a lazy and fragile heuristic: it does a linear count of
certain syntactic and whitespace elements in inlined assembly block source
code, such as a count of new-lines and semicolons (!), as a poor substitute
for "code size and complexity".Unsurprisingly this heuristic falls over and breaks its neck whith certain
common types of kernel code that use inline assembly, such as the frequent
practice of putting useful information into alternative sections.As a result of this fresh, 20+ years old GCC bug, GCC's inlining decisions
are effectively disabled for inlined functions that make use of such asm()
blocks, because GCC thinks those sections of code are "large" - when in
reality they are often result in just a very low number of machine
instructions.This absolute lack of inlining provess when GCC comes across such asm()
blocks both increases generated kernel code size and causes performance
overhead, which is particularly noticeable on paravirt kernels, which make
frequent use of these inlining facilities in attempt to stay out of the
way when running on baremetal hardware.Instead of fixing the compiler we use a workaround: we set an assembly macro
and call it from the inlined assembly block. As a result GCC considers the
inline assembly block as a single instruction. (Which it often isn't but I digress.)This uglifies and bloats the source code - for example just the refcount
related changes have this impact:Makefile | 9 +++++++--
arch/x86/Makefile | 7 +++++++
arch/x86/kernel/macros.S | 7 +++++++
scripts/Kbuild.include | 4 +++-
scripts/mod/Makefile | 2 ++
5 files changed, 26 insertions(+), 3 deletions(-)Yay readability and maintainability, it's not like assembly code is hard to read
and maintain ...We also hope that GCC will eventually get fixed, but we are not holding
our breath for that. Yet we are optimistic, it might still happen, any decade now.[ mingo: Wrote new changelog describing the background. ]
Tested-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kbuild@vger.kernel.org
Link: http://lkml.kernel.org/r/20181003213100.189959-3-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
12 Sep, 2018
1 commit
-
$(srctree) always points to the top of the source tree whether
KBUILD_SRC is set or not.Signed-off-by: Masahiro Yamada
30 Aug, 2018
1 commit
-
Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6")
bumped the minimum GCC version to 4.6 for all architectures.Remove the workaround code.
It was the only user of cc-if-fullversion. Remove the macro as well.
Signed-off-by: Masahiro Yamada
Signed-off-by: Thomas Gleixner
Cc: "H. Peter Anvin"
Cc: Michal Marek
Cc: linux-kbuild@vger.kernel.org
Link: https://lkml.kernel.org/r/1535348714-25457-1-git-send-email-yamada.masahiro@socionext.com
24 Aug, 2018
1 commit
-
Commit a0f97e06a43c ("kbuild: enable 'make CFLAGS=...' to add
additional options to CC") renamed CFLAGS to KBUILD_CFLAGS.Commit 222d394d30e7 ("kbuild: enable 'make AFLAGS=...' to add
additional options to AS") renamed AFLAGS to KBUILD_AFLAGS.Commit 06c5040cdb13 ("kbuild: enable 'make CPPFLAGS=...' to add
additional options to CPP") renamed CPPFLAGS to KBUILD_CPPFLAGS.For some reason, LDFLAGS was not renamed.
Using a well-known variable like LDFLAGS may result in accidental
override of the variable.Kbuild generally uses KBUILD_ prefixed variables for the internally
appended options, so here is one more conversion to sanitize the
naming convention.I did not touch Makefiles under tools/ since the tools build system
is a different world.Signed-off-by: Masahiro Yamada
Acked-by: Kirill A. Shutemov
Reviewed-by: Palmer Dabbelt
16 Aug, 2018
2 commits
-
Pull Kconfig updates from Masahiro Yamada:
- show clearer error messages where pkg-config is needed, but not
installed- rename SYMBOL_AUTO to SYMBOL_NO_WRITE to reflect its semantics
- create all necessary directories by Kconfig tool itself instead of
Makefile- update the .config unconditionally when syncconfig is invoked
- use 'include' directive instead of '-include' where
include/config/{auto,tristate}.conf is mandatory- do not try to update the .config when running install targets
- add .DELETE_ON_ERROR to delete partially updated files
- misc cleanups and fixes
* tag 'kconfig-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kconfig: remove P_ENV property type
kconfig: remove unused sym_get_env_prop() function
kconfig: fix the rule of mainmenu_stmt symbol
init/Kconfig: Use short unix-style option instead of --longname
Kbuild: Makefile.modbuiltin: include auto.conf and tristate.conf mandatory
kbuild: remove auto.conf from prerequisite of phony targets
kbuild: do not update config for 'make kernelrelease'
kbuild: do not update config when running install targets
kbuild: add .DELETE_ON_ERROR special target
kbuild: use 'include' directive to load auto.conf from top Makefile
kconfig: allow all config targets to write auto.conf if missing
kconfig: make syncconfig update .config regardless of sym_change_count
kconfig: create directories needed for syncconfig by itself
kconfig: remove unneeded directory generation from local*config
kconfig: split out useful helpers in confdata.c
kconfig: rename file_write_dep and move it to confdata.c
kconfig: fix typos in description of "choice" in kconfig-language.txt
kconfig: handle format string before calling conf_message_callback()
kconfig: rename SYMBOL_AUTO to SYMBOL_NO_WRITE
kconfig: check for pkg-config on make {menu,n,g,x}config -
Pull Kbuild updates from Masahiro Yamada:
- verify depmod is installed before modules_install
- support build salt in case build ids must be unique between builds
- allow users to specify additional host compiler flags via HOST*FLAGS,
and rename internal variables to KBUILD_HOST*FLAGS- update buildtar script to drop vax support, add arm64 support
- update builddeb script for better debarch support
- document the pit-fall of if_changed usage
- fix parallel build of UML with O= option
- make 'samples' target depend on headers_install to fix build errors
- remove deprecated host-progs variable
- add a new coccinelle script for refcount_t vs atomic_t check
- improve double-test coccinelle script
- misc cleanups and fixes
* tag 'kbuild-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits)
coccicheck: return proper error code on fail
Coccinelle: doubletest: reduce side effect false positives
kbuild: remove deprecated host-progs variable
kbuild: make samples really depend on headers_install
um: clean up archheaders recipe
kbuild: add %asm-generic to no-dot-config-targets
um: fix parallel building with O= option
scripts: Add Python 3 support to tracing/draw_functrace.py
builddeb: Add automatic support for sh{3,4}{,eb} architectures
builddeb: Add automatic support for riscv* architectures
builddeb: Add automatic support for m68k architecture
builddeb: Add automatic support for or1k architecture
builddeb: Add automatic support for sparc64 architecture
builddeb: Add automatic support for mips{,64}r6{,el} architectures
builddeb: Add automatic support for mips64el architecture
builddeb: Add automatic support for ppc64 and powerpcspe architectures
builddeb: Introduce functions to simplify kconfig tests in set_debarch
builddeb: Drop check for 32-bit s390
builddeb: Change architecture detection fallback to use dpkg-architecture
builddeb: Skip architecture detection when KBUILD_DEBARCH is set
...
15 Aug, 2018
1 commit
-
Pull arm64 updates from Will Deacon:
"A bunch of good stuff in here. Worth noting is that we've pulled in
the x86/mm branch from -tip so that we can make use of the core
ioremap changes which allow us to put down huge mappings in the
vmalloc area without screwing up the TLB. Much of the positive
diffstat is because of the rseq selftest for arm64.Summary:
- Wire up support for qspinlock, replacing our trusty ticket lock
code- Add an IPI to flush_icache_range() to ensure that stale
instructions fetched into the pipeline are discarded along with the
I-cache lines- Support for the GCC "stackleak" plugin
- Support for restartable sequences, plus an arm64 port for the
selftest- Kexec/kdump support on systems booting with ACPI
- Rewrite of our syscall entry code in C, which allows us to zero the
GPRs on entry from userspace- Support for chained PMU counters, allowing 64-bit event counters to
be constructed on current CPUs- Ensure scheduler topology information is kept up-to-date with CPU
hotplug events- Re-enable support for huge vmalloc/IO mappings now that the core
code has the correct hooks to use break-before-make sequences- Miscellaneous, non-critical fixes and cleanups"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (90 commits)
arm64: alternative: Use true and false for boolean values
arm64: kexec: Add comment to explain use of __flush_icache_range()
arm64: sdei: Mark sdei stack helper functions as static
arm64, kaslr: export offset in VMCOREINFO ELF notes
arm64: perf: Add cap_user_time aarch64
efi/libstub: Only disable stackleak plugin for arm64
arm64: drop unused kernel_neon_begin_partial() macro
arm64: kexec: machine_kexec should call __flush_icache_range
arm64: svc: Ensure hardirq tracing is updated before return
arm64: mm: Export __sync_icache_dcache() for xen-privcmd
drivers/perf: arm-ccn: Use devm_ioremap_resource() to map memory
arm64: Add support for STACKLEAK gcc plugin
arm64: Add stack information to on_accessible_stack
drivers/perf: hisi: update the sccl_id/ccl_id when MT is supported
arm64: fix ACPI dependencies
rseq/selftests: Add support for arm64
arm64: acpi: fix alignment fault in accessing ACPI
efi/arm: map UEFI memory map even w/o runtime services enabled
efi/arm: preserve early mapping of UEFI memory map longer for BGRT
drivers: acpi: add dependency of EFI for arm64
...
28 Jul, 2018
1 commit
-
Currently, filechk unconditionally opens the first prerequisite and
redirects it as the stdin of a filechk_* rule. Hence, every target
using $(call filechk,...) must list something as the first prerequisite
even if it is unneeded.'< $