Re: [PATCH v8 7/8] modpost: Create modalias for builtin modules

[Nicolas Schier <nsc@kernel.org>]

On Thu, Sep 18, 2025 at 10:05:51AM +0200, Alexey Gladkov wrote:
> For some modules, modalias is generated using the modpost utility and
> the section is added to the module file.
> 
> When a module is added inside vmlinux, modpost does not generate
> modalias for such modules and the information is lost.
> 
> As a result kmod (which uses modules.builtin.modinfo in userspace)
> cannot determine that modalias is handled by a builtin kernel module.
> 
> $ cat /sys/devices/pci0000:00/0000:00:14.0/modalias
> pci:v00008086d0000A36Dsv00001043sd00008694bc0Csc03i30
> 
> $ modinfo xhci_pci
> name:           xhci_pci
> filename:       (builtin)
> license:        GPL
> file:           drivers/usb/host/xhci-pci
> description:    xHCI PCI Host Controller Driver
> 
> Missing modalias "pci:v*d*sv*sd*bc0Csc03i30*" which will be generated by
> modpost if the module is built separately.
> 
> To fix this it is necessary to generate the same modalias for vmlinux as
> for the individual modules. Fortunately '.vmlinux.export.o' is already
> generated from which '.modinfo' can be extracted in the same way as for
> vmlinux.o.
> 
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> Signed-off-by: Alexey Gladkov <legion@kernel.org>
> Tested-by: Stephen Rothwell <sfr@canb.auug.org.au>
> ---
>  include/linux/module.h   |  4 ----
>  scripts/Makefile.vmlinux |  4 +++-
>  scripts/mksysmap         |  3 +++
>  scripts/mod/file2alias.c | 19 ++++++++++++++++++-
>  scripts/mod/modpost.c    | 15 +++++++++++++++
>  scripts/mod/modpost.h    |  2 ++
>  6 files changed, 41 insertions(+), 6 deletions(-)
> 

Reviewed-by: Nicolas Schier <nsc@kernel.org>

-- 
Nicolas