linux-kernel - [PATCH v2] asm-generic: bug: unify hints for BUG

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Date:   Sat,  8 Sep 2018 07:59:28 +0300
From:   Igor Stoppa <igor.stoppa@...il.com>
To:     Arnd Bergmann <arnd@...db.de>
Cc:     igor.stoppa@...il.com, Igor Stoppa <igor.stoppa@...wei.com>,
        linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] asm-generic: bug: unify hints for BUG_ON()

If BUG_ON() is used instead of BUG(), it means that probably the
preferred outcome is to not BUG(), therefore the condition tested should
be unlikely().

However, when CONFIG_PROFILE_ANNOTATED_BRANCHES is enabled, the hint is
disabled, to avoid generating false-positive warnings caused by
-Wmaybe-uninitialized.

Signed-off-by: Igor Stoppa <igor.stoppa@...wei.com>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: linux-arch@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
 include/asm-generic/bug.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 20561a60db9c..b91273c36baf 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -58,8 +58,12 @@ struct bug_entry {
 #endif
 
 #ifndef HAVE_ARCH_BUG_ON
+#ifdef CONFIG_PROFILE_ANNOTATED_BRANCHES
+#define BUG_ON(condition) do { if (condition) BUG(); } while (0)
+#else
 #define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
 #endif
+#endif
 
 #ifdef __WARN_FLAGS
 #define __WARN_TAINT(taint)		__WARN_FLAGS(BUGFLAG_TAINT(taint))
@@ -183,7 +187,11 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
 #endif
 
 #ifndef HAVE_ARCH_BUG_ON
+#ifdef CONFIG_PROFILE_ANNOTATED_BRANCHES
 #define BUG_ON(condition) do { if (condition) BUG(); } while (0)
+#else
+#define BUG_ON(condition) do { if (unlikely(condition)) BUG(); } while (0)
+#endif
 #endif
 
 #ifndef HAVE_ARCH_WARN_ON
-- 
2.17.1