Cc: Jonathan Corbet <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Luc Van Oostenryck <[email protected]>
Cc: Eli Friedman <[email protected]>
Cc: Christopher Li <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Joe Perches <[email protected]>
Cc: Dominique Martinet <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Miguel Ojeda <[email protected]>
---
Documentation/process/index.rst | 1 +
.../process/programming-language.rst | 45 +++++++++++++++++++
2 files changed, 46 insertions(+)
create mode 100644 Documentation/process/programming-language.rst
diff --git a/Documentation/process/index.rst b/Documentation/process/index.rst
index 37bd0628b6ee..c56f24a22d2a 100644
--- a/Documentation/process/index.rst
+++ b/Documentation/process/index.rst
@@ -23,6 +23,7 @@ Below are the essential guides that every developer should
read.
code-of-conflict
development-process
submitting-patches
+ programming-language
coding-style
maintainer-pgp-guide
email-clients
diff --git a/Documentation/process/programming-language.rst
b/Documentation/process/programming-language.rst
new file mode 100644
index 000000000000..e5f5f065dc24
--- /dev/null
+++ b/Documentation/process/programming-language.rst
@@ -0,0 +1,45 @@
+.. _programming_language:
+
+Programming Language
+====================
+
+The kernel is written in the C programming language [c-language]_.
+More precisely, the kernel is typically compiled with ``gcc`` [gcc]_
+under ``-std=gnu89`` [gcc-c-dialect-options]_: the GNU dialect of ISO C90
+(including some C99 features).
+
+This dialect contains many extensions to the language [gnu-extensions]_,
+and many of them are used within the kernel as a matter of course.
+
+There is some support for compiling the kernel with ``clang`` [clang]_
+and ``icc`` [icc]_ for several of the architectures, although at the time
+of writing it is not completed, requiring third-party patches.
+
+Attributes
+----------
+
+One of the common extensions used throughout the kernel are attributes
+[gcc-attribute-syntax]_. Attributes allow to introduce
+implementation-defined semantics to language entities (like variables,
+functions or types) without having to make significant syntactic changes
+to the language (e.g. adding a new keyword) [n2049]_.
+
+In some cases, attributes are optional (i.e. a compiler not supporting them
+should still produce proper code, even if it is slower or does not perform
+as many compile-time checks/diagnostics).
+
+The kernel defines pseudo-keywords (e.g. ``__pure``) instead of using
+directly the GNU attribute syntax (e.g. ``__attribute__((__pure__))``)
+in order to feature detect which ones can be used and/or to shorten the code.
+
+Please refer to ``include/linux/compiler_attributes.h`` for more information.
+
+.. [c-language] http://www.open-std.org/jtc1/sc22/wg14/www/standards
+.. [gcc] https://gcc.gnu.org
+.. [clang] https://clang.llvm.org
+.. [icc] https://software.intel.com/en-us/c-compilers
+.. [gcc-c-dialect-options]
https://gcc.gnu.org/onlinedocs/gcc/C-Dialect-Options.html
+.. [gnu-extensions] https://gcc.gnu.org/onlinedocs/gcc/C-Extensions.html
+.. [gcc-attribute-syntax]
https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html
+.. [n2049] http://www.open-std.org/jtc1/sc22/wg14/www/docs/n2049.pdf
+
--
2.17.1
