Re: [RFC PATCH 2/3] kbuild: Make sure to generate config file

[Tiezhu Yang]

On 2026/1/22 上午7:47, Nathan Chancellor wrote:
> Hi Tiezhu,
>
> On Tue, Jan 20, 2026 at 08:37:29PM +0800, Tiezhu Yang wrote:
> > After commit 75cffd392bfa ("LoongArch: Using generic scripts/install.sh
> > in `make install`"), arch/loongarch/boot/install.sh is usually not used,
> > either /root/bin/installkernel or /sbin/installkernel is used if found.
> >
> > Then it can not generate the config file in most cases, just copy it to
> > the installation path. Otherwise there may be an error when testing bpf,
> > for example.
> >
> >    $ ./test_verifier
> >    gzopen /boot/config-6.19.0-rc6: No such file or directorg
>
> This could also be resolved by enabling CONFIG_IKCONFIG_PROC.

Currently, CONFIG_IKCONFIG_PROC is set by default on LoongArch,
the above error still exists, it checks /boot/config-* first,
here is the related code:

tools/testing/selftests/bpf/unpriv_helpers.c:
static gzFile open_config(void)
{
        struct utsname uts;
        char buf[PATH_MAX];
        gzFile config;

        if (uname(&uts)) {
                perror("uname");
                goto config_gz;
        }

        snprintf(buf, sizeof(buf), "/boot/config-%s", uts.release);
        config = gzopen(buf, "rb");
        if (config)
                return config;
        fprintf(stderr, "gzopen %s: %s\n", buf, strerror(errno));

config_gz:
        config = gzopen("/proc/config.gz", "rb");
        if (!config)
                perror("gzopen /proc/config.gz");
        return config;
}

> > Signed-off-by: Tiezhu Yang <yangtiezhu@xxxxxxxxxxx>
> > ---
> >   scripts/install.sh | 6 ++++++
> >   1 file changed, 6 insertions(+)
> >
> > diff --git a/scripts/install.sh b/scripts/install.sh
> > index 05d62ac513ee..ecf354d8f4f1 100755
> > --- a/scripts/install.sh
> > +++ b/scripts/install.sh
> > @@ -34,6 +34,12 @@ do
> >   		continue
> >   	fi
> >   
> > +	# Install kernel config file
> > +	if [ -f ${INSTALL_PATH}/config-${KERNELRELEASE} ]; then
> > +	  mv ${INSTALL_PATH}/config-${KERNELRELEASE} ${INSTALL_PATH}/config-${KERNELRELEASE}.old
> > +	fi
> > +	cp .config ${INSTALL_PATH}/config-${KERNELRELEASE}
> > +
>
> I am a little hesistant to change the generic install logic to handle
> these files, especially since the map file should be handled by
> installkernel like you mention in patch 3 (but I am open to other
> opinions/arguments) and the configuration can be made available via
> CONFIG_IKCONFIG_PROC as I mention above.
>
> If LoongArch wants this behavior as part of its install process, why not
> just bring back the lines of 75cffd392bfa after $(cmd,install)
>
> install:
>      $(call cmd,install)
>      $(Q)install -D -m 644 .config $(INSTALL_PATH)/config-$(KERNELRELEASE)
>      $(Q)install -D -m 644 System.map $(INSTALL_PATH)/System.map-$(KERNELRELEASE)
>
> >   	# installkernel(8) says the parameters are like follows:
> >   	#
> >   	#   installkernel version zImage System.map [directory]

Yes, this works well for LoongArch. If there is no need to do this for
all archs, I will only touch arch/loongarch files.

By the way, I do not know why it can not generate System.map by the
installkernel in practice, could you please check it?

Thanks,
Tiezhu