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authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-20 08:36:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-20 08:36:47 -0700
commitd7b0827f28ab3a4fd65864451ffefa695e3255fd (patch)
treeed93beb88fa420cf276b2c3fc22c02c022dde693 /Documentation
parent574cc4539762561d96b456dbc0544d8898bd4c6e (diff)
parent77564a4829ef6d309331d443ea6ceb065f3dc371 (diff)
Merge tag 'kbuild-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada: - add modpost warn exported symbols marked as 'static' because 'static' and EXPORT_SYMBOL is an odd combination - break the build early if gold linker is used - optimize the Bison rule to produce .c and .h files by a single pattern rule - handle PREEMPT_RT in the module vermagic and UTS_VERSION - warn CONFIG options leaked to the user-space except existing ones - make single targets work properly - rebuild modules when module linker scripts are updated - split the module final link stage into scripts/Makefile.modfinal - fix the missed error code in merge_config.sh - improve the error message displayed on the attempt of the O= build in unclean source tree - remove 'clean-dirs' syntax - disable -Wimplicit-fallthrough warning for Clang - add CONFIG_CC_OPTIMIZE_FOR_SIZE_O3 for ARC - remove ARCH_{CPP,A,C}FLAGS variables - add $(BASH) to run bash scripts - change *CFLAGS_<basetarget>.o to take the relative path to $(obj) instead of the basename - stop suppressing Clang's -Wunused-function warnings when W=1 - fix linux/export.h to avoid genksyms calculating CRC of trimmed exported symbols - misc cleanups * tag 'kbuild-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (63 commits) genksyms: convert to SPDX License Identifier for lex.l and parse.y modpost: use __section in the output to *.mod.c modpost: use MODULE_INFO() for __module_depends export.h, genksyms: do not make genksyms calculate CRC of trimmed symbols export.h: remove defined(__KERNEL__), which is no longer needed kbuild: allow Clang to find unused static inline functions for W=1 build kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARN kbuild: refactor scripts/Makefile.extrawarn merge_config.sh: ignore unwanted grep errors kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj) modpost: add NOFAIL to strndup modpost: add guid_t type definition kbuild: add $(BASH) to run scripts with bash-extension kbuild: remove ARCH_{CPP,A,C}FLAGS kbuild,arc: add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 for ARC kbuild: Do not enable -Wimplicit-fallthrough for clang for now kbuild: clean up subdir-ymn calculation in Makefile.clean kbuild: remove unneeded '+' marker from cmd_clean kbuild: remove clean-dirs syntax kbuild: check clean srctree even earlier ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kbuild/kbuild.rst28
-rw-r--r--Documentation/kbuild/makefiles.rst67
2 files changed, 34 insertions, 61 deletions
diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst
index 61b2181ed3ea..f1e5dce86af7 100644
--- a/Documentation/kbuild/kbuild.rst
+++ b/Documentation/kbuild/kbuild.rst
@@ -105,6 +105,15 @@ The output directory can also be specified using "O=...".
Setting "O=..." takes precedence over KBUILD_OUTPUT.
+KBUILD_EXTRA_WARN
+-----------------
+Specify the extra build checks. The same value can be assigned by passing
+W=... from the command line.
+
+See `make help` for the list of the supported values.
+
+Setting "W=..." takes precedence over KBUILD_EXTRA_WARN.
+
KBUILD_DEBARCH
--------------
For the deb-pkg target, allows overriding the normal heuristics deployed by
@@ -241,11 +250,6 @@ To get all available archs you can also specify all. E.g.::
$ make ALLSOURCE_ARCHS=all tags
-KBUILD_ENABLE_EXTRA_GCC_CHECKS
-------------------------------
-If enabled over the make command line with "W=1", it turns on additional
-gcc -W... options for more extensive build-time checking.
-
KBUILD_BUILD_TIMESTAMP
----------------------
Setting this to a date string overrides the timestamp used in the
@@ -258,17 +262,3 @@ KBUILD_BUILD_USER, KBUILD_BUILD_HOST
These two variables allow to override the user@host string displayed during
boot and in /proc/version. The default value is the output of the commands
whoami and host, respectively.
-
-KBUILD_LDS
-----------
-The linker script with full path. Assigned by the top-level Makefile.
-
-KBUILD_VMLINUX_OBJS
--------------------
-All object files for vmlinux. They are linked to vmlinux in the same
-order as listed in KBUILD_VMLINUX_OBJS.
-
-KBUILD_VMLINUX_LIBS
--------------------
-All .a "lib" files for vmlinux. KBUILD_VMLINUX_OBJS and KBUILD_VMLINUX_LIBS
-together specify all the object files used to link vmlinux.
diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index f4f0f7ffde2b..6ba9d5365ff3 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -471,21 +471,6 @@ more details, with real examples.
The second argument is optional, and if supplied will be used
if first argument is not supported.
- cc-ldoption
- cc-ldoption is used to check if $(CC) when used to link object files
- supports the given option. An optional second option may be
- specified if first option are not supported.
-
- Example::
-
- #arch/x86/kernel/Makefile
- vsyscall-flags += $(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
-
- In the above example, vsyscall-flags will be assigned the option
- -Wl$(comma)--hash-style=sysv if it is supported by $(CC).
- The second argument is optional, and if supplied will be used
- if first argument is not supported.
-
as-instr
as-instr checks if the assembler reports a specific instruction
and then outputs either option1 or option2
@@ -765,7 +750,8 @@ Files matching the patterns "*.[oas]", "*.ko", plus some additional files
generated by kbuild are deleted all over the kernel src tree when
"make clean" is executed.
-Additional files can be specified in kbuild makefiles by use of $(clean-files).
+Additional files or directories can be specified in kbuild makefiles by use of
+$(clean-files).
Example::
@@ -776,23 +762,8 @@ When executing "make clean", the file "crc32table.h" will be deleted.
Kbuild will assume files to be in the same relative directory as the
Makefile, except if prefixed with $(objtree).
-To delete a directory hierarchy use:
-
- Example::
-
- #scripts/package/Makefile
- clean-dirs := $(objtree)/debian/
-
-This will delete the directory debian in the toplevel directory, including all
-subdirectories.
-
-To exclude certain files from make clean, use the $(no-clean-files) variable.
-This is only a special case used in the top level Kbuild file:
-
- Example::
-
- #Kbuild
- no-clean-files := $(bounds-file) $(offsets-file)
+To exclude certain files or directories from make clean, use the
+$(no-clean-files) variable.
Usually kbuild descends down in subdirectories due to "obj-* := dir/",
but in the architecture makefiles where the kbuild infrastructure
@@ -988,13 +959,25 @@ When kbuild executes, the following steps are followed (roughly):
$(KBUILD_ARFLAGS) set by the top level Makefile to "D" (deterministic
mode) if this option is supported by $(AR).
- ARCH_CPPFLAGS, ARCH_AFLAGS, ARCH_CFLAGS Overrides the kbuild defaults
+ KBUILD_LDS
+
+ The linker script with full path. Assigned by the top-level Makefile.
+
+ KBUILD_LDS_MODULE
+
+ The module linker script with full path. Assigned by the top-level
+ Makefile and additionally by the arch Makefile.
+
+ KBUILD_VMLINUX_OBJS
+
+ All object files for vmlinux. They are linked to vmlinux in the same
+ order as listed in KBUILD_VMLINUX_OBJS.
- These variables are appended to the KBUILD_CPPFLAGS,
- KBUILD_AFLAGS, and KBUILD_CFLAGS, respectively, after the
- top-level Makefile has set any other flags. This provides a
- means for an architecture to override the defaults.
+ KBUILD_VMLINUX_LIBS
+ All .a "lib" files for vmlinux. KBUILD_VMLINUX_OBJS and
+ KBUILD_VMLINUX_LIBS together specify all the object files used to
+ link vmlinux.
6.2 Add prerequisites to archheaders
------------------------------------
@@ -1139,7 +1122,7 @@ When kbuild executes, the following steps are followed (roughly):
header-test-y
- header-test-y specifies headers (*.h) in the current directory that
+ header-test-y specifies headers (`*.h`) in the current directory that
should be compile tested to ensure they are self-contained,
i.e. compilable as standalone units. If CONFIG_HEADER_TEST is enabled,
this builds them as part of extra-y.
@@ -1147,11 +1130,11 @@ When kbuild executes, the following steps are followed (roughly):
header-test-pattern-y
This works as a weaker version of header-test-y, and accepts wildcard
- patterns. The typical usage is:
+ patterns. The typical usage is::
- header-test-pattern-y += *.h
+ header-test-pattern-y += *.h
- This specifies all the files that matches to '*.h' in the current
+ This specifies all the files that matches to `*.h` in the current
directory, but the files in 'header-test-' are excluded.
6.7 Commands useful for building a boot image