Kbuild brought about many advantages for us but a significant
performance regression was reported by Simon Glass.
After some discussions and analysis, it turned out
its main cause is in $(call cc-option,...).
Historically, U-Boot parses all config.mk
(arch/*/config.mk and board/*/config.mk)
every time descending into subdirectories.
That means cc-options are evaluated over and over again.
$(call cc-option,...) is useful but costly.
So we want to evaluate them only in ./Makefile
and spl/Makefile and export compiler flags.
This commit changes the build system as follows:
- Modify scripts/Makefile.build to not include config.mk
Instead, add $(PLATFORM_CPPFLAGS) to asflags-y, ccflags-y,
cppflags-y.
- Export many variables
Going forward, Kbuild will not parse config.mk files
when it descends into subdirectories.
If we want to set variables in config.mk and use them
in subdirectories, they must be exported.
This is the list of variables to get exported:
PLATFORM_CPPFLAGS
CPUDIR
BOARDDIR
OBJCOPYFLAGS
LDFLAGS
LDFLAGS_FINAL
(used in nand_spl/board/*/*/Makefile)
CONFIG_STANDALONE_LOAD_ADDR
(used in examples/standalone/Makefile)
SYM_PREFIX
(used in examples/standalone/Makefile)
RELFLAGS
(used in examples/standalone/Makefile)
- Delete CPPFLAGS
This variable has been replaced with PLATFORM_CPPFLAGS
- Copy gcclibdir from example/standalone/Makefile
to arch/sparc/config.mk
The reference in CONFIG_STANDALONE_LOAD_ADDR must be
resolved before it is exported.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Reported-by: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org> [on Sandbox]
Tested-by: Stephen Warren <swarren@nvidia.com> [on Tegra]
This commit changes the location of include directives
of board configuration files.
The purpose of this change is:
- Slim down $(TOPDIR)/config.mk
- Prevent $(TOPDIR)/Makefile from including the same
configuration file twice
- Do not include include/config.mk multiple times
because ARCH, CPU, BOARD, VENDOR, SOC are exported
Before this commit:
- include/autoconf.mk was included from $(TOPDIR)/Makefile
and $(TOPDIR)/config.mk
(This means $(TOPDIR)/Makefile included include/autoconf.mk twice)
- include/{spl,tpl}-autoconf.mk was included from $(TOPDIR)/config.mk
- include/config.mk was included from $(TOPDIR)/Makefile
and $(TOPDIR)/config.mk
(This means $(TOPDIR)/Makefile included include/config.mk twice)
After this commit:
- include/autoconf.mk is included from $(TOPDIR)/Makefile
and $(TOPDIR)/scripts/Makefile.build
- include/{spl,tpl}-autoconf.mk is included from $(TOPDIR)/spl/Makefile
and $(TOPDIR)/scripts/Makefile.build
- include/config.mk is included from $(TOPDIR)/config.mk and
$(TOPDIR)/spl/Makefile
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Now we are ready to switch over to real Kbuild.
This commit disables temporary scripts:
scripts/{Makefile.build.tmp, Makefile.host.tmp}
and enables real Kbuild scripts:
scripts/{Makefile.build,Makefile.host,Makefile.lib}.
This switch is triggered by the line in scripts/Kbuild.include
-build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build.tmp obj
+build := -f $(if $(KBUILD_SRC),$(srctree)/)scripts/Makefile.build obj
We need to adjust some build scripts for U-Boot.
But smaller amount of modification is preferable.
Additionally, we need to fix compiler flags which are
locally added or removed.
In Kbuild, it is not allowed to change CFLAGS locally.
Instead, ccflags-y, asflags-y, cppflags-y,
CFLAGS_$(basetarget).o, CFLAGS_REMOVE_$(basetarget).o
are prepared for that purpose.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>
This commit imports build scripts from Linux Kernel v3.13
as they are.
I know they include some trailing spaces
but I am intentionally keeping them untouched.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Some build scripts including scripts/Makefile.build
will be imported from Linux Kernel in the next commit.
We need to adjust them for U-Boot in the following commits.
To make it easier for reviewers to track the modification,
this commit renames scripts/Makefile.build to
scripts/Makefile.build.tmp beforehand.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
This commit changes the working directory
where the build process occurs.
Before this commit, build process occurred under the source
tree for both in-tree and out-of-tree build.
That's why we needed to add $(obj) prefix to all generated
files in makefiles like follows:
$(obj)u-boot.bin: $(obj)u-boot
Here, $(obj) is empty for in-tree build, whereas it points
to the output directory for out-of-tree build.
And our old build system changes the current working directory
with "make -C <sub-dir>" syntax when descending into the
sub-directories.
On the other hand, Kbuild uses a different idea
to handle out-of-tree build and directory descending.
The build process of Kbuild always occurs under the output tree.
When "O=dir/to/store/output/files" is given, the build system
changes the current working directory to that directory and
restarts the make.
Kbuild uses "make -f $(srctree)/scripts/Makefile.build obj=<sub-dir>"
syntax for descending into sub-directories.
(We can write it like "make $(obj)=<sub-dir>" with a shorthand.)
This means the current working directory is always the top
of the output directory.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Tested-by: Gerhard Sittig <gsi@denx.de>
This commit adjusts some files to use Kbuild.include.
- Use cc-option defined in Kbuild.include
(Delete cc-option in config.mk)
- Use cc-version defined in
(Delete cc-version in config.mk)
- Move binutils-version and dtc-version to Kbuild.include
by analogy to cc-version
This commit also adds srctree (same as SRCTREE)
to use Kbuild scripts.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
This commit moves suffix rules from config.mk
to scripts/Makefile.build, which will allow us
to switch smoothly to real Kbuild.
Note1:
post/lib_powerpc/fpu/Makefile has
its own rule to compile C sources.
We need to tweak it to keep the same behavior.
Note2:
There are two file2 with the same name:
arch/arm/lib/crt0.S and eamples/api/crt0.S.
To keep the same build behavior,
examples/api/Makefile also has to be treaked.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
This commit adds scripts/Makefile.host.tmp which will
be used in the next commit to convert makefiles
under tools/ directory to Kbuild style.
Notice this script, scripts/Makefile.host.tmp
is temporary.
When switching over to real Kbuild,
it will be replaced with scripts/Makefile.host of Linux Kernel.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
The support for COBJS, COBJS-y, SOBJS, SOBJS-y, GLCOBJS, GLSOBJS
from scripts/Makefile.build.
Going forward we need to use Kbuild style consistently.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
This patch tweaks scripts/Makefile.build to allow
the build system to descend into subdirectories like Kbuild.
To use this feature, use "obj-y += foo/" syntax.
Example:
obj-$(CONFIG_FOO) += foo/
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
Every makefile in sub directories has common lines
at the top and the bottom.
This commit pushes the common parts into script/Makefile.build.
Going forward sub-makefiles only need to describe this part:
COBJS := ...
COBJS += ...
SOBJS := ...
But using obj-y is preferable to prepare for switching to Kbuild.
The conventional (non-Kbuild) Makefile style is still supported.
This is achieved by greping the Makefile before entering into it.
U-Boot conventional sub makefiles always include some other makefiles.
So the build system searches a line beginning with "include" keyword
in the makefile in order to distinguish which style it is.
If the Makefile include a "include" line, we assume it is a conventional
U-Boot style. Otherwise, it is treated as a Kbuild-style makefile.
With this tweak, we can switch sub-makefiles
from U-Boot style to Kbuild style little by little.
obj-y := foo/
syntax (descending into the sub directory) is not supportd yet.
It will be implemented in the upcomming commit.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Tom Rini <trini@ti.com>
Masahiro Yamada