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From: Masahiro Yamada <masahiroy@kernel.org>
To: linux-kbuild@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Marco Elver <elver@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH] Revert "kbuild: avoid static_assert for genksyms"
Date: Sun, 20 Dec 2020 03:39:10 +0900
Message-ID: <20201219183911.181442-1-masahiroy@kernel.org> (raw)

This reverts commit 14dc3983b5dff513a90bd5a8cc90acaf7867c3d0.

Macro Elver had sent a fix proper fix earlier, and also pointed out
corner cases:

"I guess what you propose is simpler, but might still have corner cases
where we still get warnings. In particular, if some file (for whatever
reason) does not include build_bug.h and uses a raw _Static_assert(),
then we still get warnings. E.g. I see 1 user of raw _Static_assert()
(drivers/gpu/drm/amd/amdgpu/amdgv_sriovmsg.h )."

I believe the raw use of _Static_assert() should be allowed, so this
should be fixed in genksyms.

Even after commit 14dc3983b5df ("kbuild: avoid static_assert for
genksyms"), I confirmed the following test code emits the warning.

  ---------------->8----------------
  #include <linux/export.h>

  _Static_assert((1 ?: 0), "");

  void foo(void) { }
  EXPORT_SYMBOL(foo);
  ---------------->8----------------

  WARNING: modpost: EXPORT symbol "foo" [vmlinux] version generation failed, symbol will not be versioned.

Now that commit 869b91992bce ("genksyms: Ignore module scoped
_Static_assert()") fixed this issue properly, the workaround should
be reverted.

Link: https://lkml.org/lkml/2020/12/10/845
Cc: Marco Elver <elver@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

I will apply this after Macro's patch is pulled.



 include/linux/build_bug.h | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/include/linux/build_bug.h b/include/linux/build_bug.h
index 7bb66e15b481..e3a0be2c90ad 100644
--- a/include/linux/build_bug.h
+++ b/include/linux/build_bug.h
@@ -77,9 +77,4 @@
 #define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
 #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
 
-#ifdef __GENKSYMS__
-/* genksyms gets confused by _Static_assert */
-#define _Static_assert(expr, ...)
-#endif
-
 #endif	/* _LINUX_BUILD_BUG_H */
-- 
2.27.0


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Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-19 18:39 Masahiro Yamada [this message]
2020-12-23  6:15 ` Masahiro Yamada

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