Re: [PATCH v9 3/5] modules: Allow extended modversions without basic MODVERSIONS

If you know that your kernel modules will only ever be loaded by a newer
kernel, you can disable BASIC_MODVERSIONS to save space. This also
allows easy creation of test modules to seee how tooling will respond to
modules that only have the new format.

Signed-off-by: Matthew Maurer <redacted>
---
 kernel/module/Kconfig    | 15 +++++++++++++++
 scripts/Makefile.modpost |  1 +
 scripts/mod/modpost.c    | 19 +++++++++++--------
 3 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/kernel/module/Kconfig b/kernel/module/Kconfig
index a31c617cd67d3d66b24d2fba34cbd5cc9c53ab78..f28b361494c4b4cc2446d683589f9452a0043b2b 100644
--- a/kernel/module/Kconfig
+++ b/kernel/module/Kconfig

@@ -161,6 +161,7 @@ config MODULE_UNLOAD_TAINT_TRACKING
 config MODVERSIONS
 	bool "Module versioning support"
 	depends on !COMPILE_TEST
+	selects BASIC_MODVERSIONS

 	help
 	  Usually, you have to use modules compiled with your kernel.
 	  Saying Y here makes it sometimes possible to use modules

@@ -218,6 +219,20 @@ config EXTENDED_MODVERSIONS
 	  The most likely reason you would enable this is to enable Rust
 	  support. If unsure, say N.
 
+config BASIC_MODVERSIONS
+	bool "Basic Module Versioning Support"
+	depends on MODVERSIONS
+	help
+	  This enables basic MODVERSIONS support, allowing older tools or
+	  kernels to potentially load modules.
+
+	  Disabling this may cause older `modprobe` or `kmod` to be unable
+	  to read MODVERSIONS information from built modules. With this
+	  disabled, older kernels may treat this module as unversioned.
+
+	  This is enabled by default when MODVERSIONS are enabled.
+	  If unsure, say Y.
+
 config MODULE_SRCVERSION_ALL
 	bool "Source checksum for all modules"
 	help