Re: [PATCH net-next v3 1/2] tools: ynl: Allow cross-compiling ynl and associated tools

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Hi,

On 9/9/26 03:11, Bobby Eshleman wrote:
> On Mon, Sep 07, 2026 at 06:14:35PM +0200, Maxime Chevallier (Netdev Foundation) wrote:
>> The ynl tool and libraries may be built standalone or through the
>> drivers/net/hw selftest machinery. This may target a different arch, so
>> we need to take the CROSS_COMPILE variable into account for LLVM and
>> gcc.
>>
>> Let's include the tools/scripts/Makefile.include that deals with the
>> CC/AR resolution.
>>
>> Fixup the ynltool CFLAGS handling to use +=, so that we don't override
>> the ones set in Makefile.include.
>>
>> Makefile.include also sets the Q variable for verbose mode, so we can
>> drop it from the ynltool Makefile. This will allow properly selection
>> the verbosity of ynltool builds with the V=1 make flag.
>>
>> Reviewed-by: Matthieu Baerts (Netdev Foundation) <matttbe@kernel.org>
>> Signed-off-by: Maxime Chevallier (Netdev Foundation) <maxime.chevallier@bootlin.com>
> 
> Hey Maxime,
> 
> It seems that this patch may break some invocations of make:
> 
>   # make -C tools/net/ynl/ynltool O=/tmp/o1
>   make: Entering directory '/data/users/bobbyeshleman/linux-worktrees/review/tools/net/ynl/ynltool'
>   make: *** No rule to make target '/tmp/o1/json_writer.o', needed by '/tmp/o1/ynltool'.  Stop.
>   make: Leaving directory '/data/users/bobbyeshleman/linux-worktrees/review/tools/net/ynl/ynltool'
> 

Indeed, but looks like the command you're mentionning never worked as expected in the
first place, passing O=/tmp/xxx triggers the bug, but before the patch, O=/tmp/xxx
just does nothing, out-of-tree build just never worked for ynltool :

Before this patch :

$ make -C tools/net/ynl/ynltool O=/tmp/o1 V=1 
make: Entering directory '/home/mchevallier/work/netdev/linux/tools/net/ynl/ynltool'
	CC json_writer.o
	CC main.o
	CC page-pool.o
	CC qstats.o
	LINK ynltool
make: Leaving directory '/home/mchevallier/work/netdev/linux/tools/net/ynl/ynltool'
$ ls /tmp/o1/
$

The fix is simple though:

-%.o: %.c ../libynl.a
+$(OUTPUT)%.o: %.c ../libynl.a

I'll send the followup rightaway.

Side-note, out-of-tree build doesn't work for other ynl tools and utilities, but at least
trying to do so doesn't error-out.

Thanks for the report,

Maxime