Based on the following Linux commits:
- 54a702f70589 ("kbuild: mark $(targets) as .SECONDARY and remove
.PRECIOUS markers")
- 8e9b61b293d9 ("kbuild: move .SECONDARY special target to
Kbuild.include")
GNU Make automatically deletes intermediate files that are updated
in a chain of pattern rules.
Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
Example 2) %.o <- %.c <- %.c_shipped
A couple of makefiles mark such targets as .PRECIOUS to prevent Make
from deleting them, but the correct way is to use .SECONDARY.
.SECONDARY
Prerequisites of this special target are treated as intermediate
files but are never automatically deleted.
.PRECIOUS
When make is interrupted during execution, it may delete the target
file it is updating if the file was modified since make started.
If you mark the file as precious, make will never delete the file
if interrupted.
Both can avoid deletion of intermediate files, but the difference is
the behavior when Make is interrupted; .SECONDARY deletes the target,
but .PRECIOUS does not.
The use of .PRECIOUS is relatively rare since we do not want to keep
partially constructed (possibly corrupted) targets.
.SECONDARY with no prerequisites causes all targets to be treated as
secondary. This agrees the policy of Kbuild.
scripts/Kbuild.include seems a suitable place to add it because it is
included from almost all sub-makes.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from. So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry. Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.
In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.
This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents. There's also a few places where I found we did not have a tag
and have introduced one.
Signed-off-by: Tom Rini <trini@konsulko.com>
$(call if_changed,...) must take FORCE as a prerequite.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
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 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 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>
All objects under post/ directory are enabled by CONFIG_HAS_POST.
(post/tests.o is enabled by CONFIG_POST_STD_LIST.
But CONFIG_POST_STD_LIST depends on CONFIG_HAS_POST.)
We can move CONFIG_HAS_POST switch to the top Makefile.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
It appears that with recent versions of GCC the explicit
"-mhard-float" command line option takes precedence over the
``asm(".gnu_attribute 4, 2");'' in the source file, so this no longer
helps to avoid the warnings we get when linking code that uses FP
instructions with other code that was built using soft-float.
We can remove the ".gnu_attribute" (which appears to carry no other
information, at least so far) from the object files, but we also have
to make sure we don't pull in the __gcc_qsub() and __gcc_qmul()
functions from the standard libgcc, as these would again "infect" our
linking. We copy this code from:
gcc-4.2.2/gcc/config/rs6000/darwin-ldouble.c
This old version was chosen because it was still available under a
compatible license (GCC v2+). The file was stripped down to the
needed parts, and reformatted so it passes checkpatch with only one
warning (do not add new typedefs).
Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Stefan Roese <sr@denx.de>
Cc: Andy Fleming <afleming@gmail.com>
Cc: Kim Phillips <kim.phillips@freescale.com>
Tested-by: Stefan Roese <sr@denx.de>
Tested-by: Anatolij Gustschin <agust@denx.de>
Fix:
20001122-1.c: In function 'fpu_post_test_math1':
20001122-1.c:37:22: warning: variable 'p' set but not used [-Wunused-but-set-variable]
Signed-off-by: Stefan Roese <sr@denx.de>
If we built POST on PPC's that didn't enable CONFIG_SYS_POST_FPU we'd
get the following warning with newer toolchains:
powerpc-linux-gnu-ld: Warning: lib_powerpc/fpu/libpostpowerpcfpu.o
uses hard float, libpost.o uses soft float
We actually worked around this sometime ago with the following commit:
commit ce82ff0538
Author: Yuri Tikhonov <yur@emcraft.com>
Date: Sat Dec 20 14:54:21 2008 +0300
FPU POST: fix warnings when building with 2.18 binutils
However, this only took into effect if CONFIG_SYS_POST_FPU was enabled.
We can simply move the GNU_FPOST_ATTR out of the CONFIG_SYS_POST_FPU
ifdef block to address the issue.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Before this commit, weak symbols were not overridden by non-weak symbols
found in archive libraries when linking with recent versions of
binutils. As stated in the System V ABI, "the link editor does not
extract archive members to resolve undefined weak symbols".
This commit changes all Makefiles to use partial linking (ld -r) instead
of creating library archives, which forces all symbols to participate in
linking, allowing non-weak symbols to override weak symbols as intended.
This approach is also used by Linux, from which the gmake function
cmd_link_o_target (defined in config.mk and used in all Makefiles) is
inspired.
The name of each former library archive is preserved except for
extensions which change from ".a" to ".o". This commit updates
references accordingly where needed, in particular in some linker
scripts.
This commit reveals board configurations that exclude some features but
include source files that depend these disabled features in the build,
resulting in undefined symbols. Known such cases include:
- disabling CMD_NET but not CMD_NFS;
- enabling CONFIG_OF_LIBFDT but not CONFIG_QE.
Signed-off-by: Sebastien Carlier <sebastien.carlier@gmail.com>
As discussed on the list, move "arch/ppc" to "arch/powerpc" to
better match the Linux directory structure.
Please note that this patch also changes the "ppc" target in
MAKEALL to "powerpc" to match this new infrastructure. But "ppc"
is kept as an alias for now, to not break compatibility with
scripts using this name.
Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Wolfgang Denk <wd@denx.de>
Acked-by: Detlev Zundel <dzu@denx.de>
Acked-by: Kim Phillips <kim.phillips@freescale.com>
Cc: Peter Tyser <ptyser@xes-inc.com>
Cc: Anatolij Gustschin <agust@denx.de>
