[PATCH] docs: kconfig: fix shell function syntax in caveats

From: Erkan Erdem

Date: Sat Sep 05 2026 - 08:41:06 EST


Kconfig separates a function name from its arguments with a comma, but
the caveats section uses Make-style whitespace in its shell calls.
These expressions expand as undefined variables rather than invoking
the shell function, so the supposedly working CC_HAS_ENDIAN_FLAG
example fails to parse.

Add the missing commas to the shell calls in this section. Keep the
Make examples unchanged.

Fixes: 316d55d55f49 ("Documentation: kconfig: document a new Kconfig macro language")
Assisted-by: LLM
Signed-off-by: Erkan Erdem <hexvalid@xxxxxxxxx>
---

The issue was found and this patch and changelog were prepared with an AI
coding assistant after a request to find a small, verifiable Linux fix.
The assistant also prepared and ran the verification described below.

Validation:
- Built the current Kconfig conf tool on macOS with Clang, Bison and Flex,
using -Wall -Wmissing-prototypes -Wstrict-prototypes -Werror.
- Extracted the documented working CC_HAS_ENDIAN_FLAG example into a
minimal Kconfig, with a test gcc-check-flag helper returning y for either
endian flag. Before: syntax errors and no helper invocations for either
CPU endianness. After: both probes execute and CC_HAS_ENDIAN_FLAG=y.
- Built the changed page alone with Sphinx, treating warnings as errors.
The complete kernel documentation set and kernel were not built.

Documentation/kbuild/kconfig-macro-language.rst | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Documentation/kbuild/kconfig-macro-language.rst b/Documentation/kbuild/kconfig-macro-language.rst
index 6163467f..e15af278 100644
--- a/Documentation/kbuild/kconfig-macro-language.rst
+++ b/Documentation/kbuild/kconfig-macro-language.rst
@@ -225,7 +225,7 @@ not work::
$(MY_TYPE) "foo"
default y

-Obviously from the design, $(shell command) is expanded in the textual
+Obviously from the design, $(shell,command) is expanded in the textual
substitution phase. You cannot pass symbols to the 'shell' function.

The following does not work as expected::
@@ -236,12 +236,12 @@ The following does not work as expected::
default "-mlittle-endian" if CPU_LITTLE_ENDIAN

config CC_HAS_ENDIAN_FLAG
- def_bool $(shell $(srctree)/scripts/gcc-check-flag ENDIAN_FLAG)
+ def_bool $(shell, $(srctree)/scripts/gcc-check-flag ENDIAN_FLAG)

Instead, you can do like follows so that any function call is statically
expanded::

config CC_HAS_ENDIAN_FLAG
bool
- default $(shell $(srctree)/scripts/gcc-check-flag -mbig-endian) if CPU_BIG_ENDIAN
- default $(shell $(srctree)/scripts/gcc-check-flag -mlittle-endian) if CPU_LITTLE_ENDIAN
+ default $(shell, $(srctree)/scripts/gcc-check-flag -mbig-endian) if CPU_BIG_ENDIAN
+ default $(shell, $(srctree)/scripts/gcc-check-flag -mlittle-endian) if CPU_LITTLE_ENDIAN

base-commit: 4d7d9486c04d917265f64c55bd23b2cc4fe7749c
--
2.50.1 (Apple Git-155)