MIPS parallel build breakage

[Antony Pavlov]

On Fri, 2 Mar 2018 13:34:01 +0100
Sascha Hauer <s.hauer at pengutronix.de> wrote:

> On Fri, Mar 02, 2018 at 03:17:35PM +0300, Antony Pavlov wrote:
> > On Thu, 1 Mar 2018 12:07:29 +0100
> > Sascha Hauer <s.hauer at pengutronix.de> wrote:
> > 
> > > Hi Sam and Antony,
> > > 
> > > (Antony because you introduced this and Sam because you have intimate
> > > knowledge with our build system ;)
> > > 
> > > I am trying to solve a problem that annoys me for some years now. The
> > > problem is that the MIPS defconfigs regularly fail in my autobuilder.
> > > I usually help myself with trying it again and most of the time it
> > > then works, but doing this for years increases the pressure to do
> > > something.
> > > 
> > > What happens is that the MIPS builds use include/generated/compile.h:
> > > 
> > > > arch/mips/include/asm/pbl_macros.h:28:#include <generated/compile.h>
> > > 
> > > This often ends in:
> > > 
> > > > In file included from arch/mips/boot/start.S:20:0: arch/mips/include/asm/pbl_macros.h:28:31:
> > > > fatal error: generated/compile.h: No such file or directory
> > > > compilation terminated.
> > > 
> > > include/generated/compile.h is generated in common/Makefile:
> > > 
> > > > include/generated/compile.h: FORCE
> > > > 	@$($(quiet)chk_compile.h)
> > > > 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
> > > > 	"$(UTS_MACHINE)" "$(CC) $(KBUILD_CFLAGS)"
> > > 
> > > Other users of this file add an explicit dependency on it:
> > > 
> > > > # dependencies on generated files need to be listed explicitly
> > > > $(obj)/version.o: include/generated/compile.h
> > > 
> > > This only seems to work though when the dependent file is in the same
> > > directory, but not when the file is in arch/mips/boot/.
> > > 
> > > I tried doing the include/generated/compile.h in Makefile instead of
> > > common/Makefile, but then the version counting gets confused and causes
> > > unnecessary rebuilds.
> > > 
> > > Any ideas how to solve this?
> > 
> > I can't reproduce parallel build breakage.
> 
> The failure starts here when using 6 threads or more and only when
> compiling the black-swift_defconfig. After one successful build I can
> reproduce this reliably here with:
> 
> rm -f include/generated/compile.h && make -j 6
> 
> > But I see another problem:
> > the version string inside mips pbl binary is differ from the version string
> > inside main barebox binary.
> > 
> > I suppose that the problem is that current build system handles mips asm files
> > (which are actually use generated compile.h) and c-files in a different way.
> 
> Ups. How do the strings differ?

insert generated version into pbl by using mips_barebox_10h:

barebox$ git diff
diff --git a/arch/mips/boards/qemu-malta/include/board/board_pbl_start.h b/arch/mips/boards/qemu-malta/include/board/board_pbl_start.h
index 5c1537262e..6e85a7009a 100644
--- a/arch/mips/boards/qemu-malta/include/board/board_pbl_start.h
+++ b/arch/mips/boards/qemu-malta/include/board/board_pbl_start.h
@@ -43,18 +43,8 @@
        .set    push
        .set    noreorder
 
-       b       __start
-        nop
+       mips_barebox_10h
 
-       /*
-          On MIPS Technologies boards
-          0x1fc00010 address is reserved for BoardID
-       */
-       .org    0x10
-       .word   0xffffffff
-       .word   0xffffffff
-
-__start:
        mips_disable_interrupts
 
        /* cpu specific setup ... */
barebox$ make mrproper
...
barebox$ export ARCH=mips
barebox$ export CROSS_COMPILE=mips-linux-gnu-
barebox$ make qemu-malta_defconfig
...
barebox$ make -j3 -s
...
barebox$ xxd barebox-flash-image | head -n 6
00000000: 1000 0017 0000 0000 0000 0000 0000 0000  ................
00000010: 6261 7265 626f 7820 3230 3138 2e30 322e  barebox 2018.02.
00000020: 302d 3030 3037 392d 6731 6564 6462 3064  0-00079-g1eddb0d
00000030: 3338 322d 6469 7274 7920 2330 2046 7269  382-dirty #0 Fri
                                                           ^^^^^^^
00000040: 204d 6172 2032 2031 363a 3032 3a32 3920   Mar 2 16:02:29 
00000050: 4d53 4b20 3230 3138 0000 0000 0000 0000  MSK 2018........

#0, 16:02:29 !!!!!!!!

barebox$ qemu-system-mips -nodefaults -M malta -m 256 \
>                          -nographic -serial stdio -monitor null \
>                          -bios barebox-flash-image


barebox 2018.02.0-00079-g1eddb0d382-dirty #1 Fri Mar 2 16:02:38 MSK 2018
                                        ^^^^^^^

#1, 16:02:38 !!!!!!!!

> Another obvious way to fix the issue is to remove UTS_RELEASE and
> UTS_VERSION from the pbl headers. Would that be an option?

It isn't a __good__ option.

-- 
Best regards,
  Antony Pavlov