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From:   Kees Cook <keescook@chromium.org>
To:     Jonathan Corbet <corbet@lwn.net>
Cc:     Kees Cook <keescook@chromium.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org
Subject: [RFC] docs: Define c_paren_attributes for attributes with arguments
Date:   Fri,  2 Sep 2022 15:35:07 -0700
Message-Id: <20220902223507.2537469-1-keescook@chromium.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

While Sphinx's "c_id_attributes" is needed for basic attributes, any
attributes with arguments need to be defined in "c_paren_attributes"
to avoid errors like:

include/linux/fortify-string.h:116: warning: Function parameter or member '__builtin_strncpy' not described in '__diagnose_as'
include/linux/fortify-string.h:116: warning: Function parameter or member '1' not described in '__diagnose_as'
include/linux/fortify-string.h:116: warning: Function parameter or member '2' not described in '__diagnose_as'
include/linux/fortify-string.h:116: warning: Function parameter or member '3' not described in '__diagnose_as'

Move such attributes to "c_paren_attributes" and add __alloc_size
and __diagnose_as to the list.

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
This patch is a lie (the above warning is actually not fixed), but I
was hoping someone could help with this. The Sphinx documentation says:

c_paren_attributes
  A list of strings that the parser additionally should accept as
  attributes with one argument. That is, if my_align_as is in the list,
  then my_align_as(X) is parsed as an attribute for all strings X that
  have balanced braces ((), [], and {}). This can for example be used
  when attributes have been #define d for portability.

However, this appears to only work for attributes with literally a single
argument not "all strings X", so things like __printf and __diagnose_as
don't work.

Does this need fixing in Sphinx? Or am I missing something?
---
 Documentation/conf.py | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/Documentation/conf.py b/Documentation/conf.py
index 934727e23e0e..17f996e3709f 100644
--- a/Documentation/conf.py
+++ b/Documentation/conf.py
@@ -59,18 +59,14 @@ if major >= 3:
 
             # include/linux/compiler_attributes.h:
             "__alias",
-            "__aligned",
             "__aligned_largest",
             "__always_inline",
-            "__assume_aligned",
             "__cold",
             "__attribute_const__",
             "__copy",
             "__pure",
             "__designated_init",
             "__visible",
-            "__printf",
-            "__scanf",
             "__gnu_inline",
             "__malloc",
             "__mode",
@@ -80,7 +76,6 @@ if major >= 3:
             "__noreturn",
             "__packed",
             "__pure",
-            "__section",
             "__always_unused",
             "__maybe_unused",
             "__used",
@@ -97,6 +92,21 @@ if major >= 3:
 
             # include/linux/linkage.h:
             "asmlinkage",
+
+            # include/linux/fortify-string.h:
+            "__FORTIFY_INLINE",
+        ]
+
+        # Same as c_id_attributes above, but for those with arguments.
+        c_paren_attributes = [
+            # include/linux/compiler_attributes.h:
+            "__aligned",
+            "__alloc_size",
+            "__assume_aligned",
+            "__diagnose_as",
+            "__printf",
+            "__scanf",
+            "__section",
         ]
 
 else:
-- 
2.34.1