kbuild: rust: re-run Kconfig if the version text changes
Re-run Kconfig if we detect the Rust compiler has changed via the version
text, like it is done for C.
Unlike C, and unlike `RUSTC_VERSION`, the `RUSTC_VERSION_TEXT` is kept
under `depends on RUST`, since it should not be needed unless `RUST`
is enabled.
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20240902165535.1101978-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
diff --git a/Makefile b/Makefile
index 68ebd6d..1883aeb 100644
--- a/Makefile
+++ b/Makefile
@@ -648,9 +648,11 @@
# The expansion should be delayed until arch/$(SRCARCH)/Makefile is included.
# Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
-# CC_VERSION_TEXT is referenced from Kconfig (so it needs export),
-# and from include/config/auto.conf.cmd to detect the compiler upgrade.
+# CC_VERSION_TEXT and RUSTC_VERSION_TEXT are referenced from Kconfig (so they
+# need export), and from include/config/auto.conf.cmd to detect the compiler
+# upgrade.
CC_VERSION_TEXT = $(subst $(pound),,$(shell LC_ALL=C $(CC) --version 2>/dev/null | head -n 1))
+RUSTC_VERSION_TEXT = $(subst $(pound),,$(shell $(RUSTC) --version 2>/dev/null))
ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
include $(srctree)/scripts/Makefile.clang
@@ -671,7 +673,7 @@
# KBUILD_DEFCONFIG may point out an alternative default configuration
# used for 'make defconfig'
include $(srctree)/arch/$(SRCARCH)/Makefile
-export KBUILD_DEFCONFIG KBUILD_KCONFIG CC_VERSION_TEXT
+export KBUILD_DEFCONFIG KBUILD_KCONFIG CC_VERSION_TEXT RUSTC_VERSION_TEXT
config: outputmakefile scripts_basic FORCE
$(Q)$(MAKE) $(build)=scripts/kconfig $@
diff --git a/init/Kconfig b/init/Kconfig
index 38c1cfc..c6b744a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1927,7 +1927,9 @@
config RUSTC_VERSION_TEXT
string
depends on RUST
- default "$(shell,$(RUSTC) --version 2>/dev/null)"
+ default "$(RUSTC_VERSION_TEXT)"
+ help
+ See `CC_VERSION_TEXT`.
config BINDGEN_VERSION_TEXT
string
