linux-kernel - [tip:x86/urgent] x86/boot: #undef memcpy() et al in string.c

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Date:   Tue, 25 Jul 2017 06:47:03 -0700
From:   tip-bot for Michael Davidson <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     keescook@...omium.org, md@...gle.com, mka@...omium.org,
        hpa@...or.com, linux-kernel@...r.kernel.org,
        torvalds@...ux-foundation.org, ghackmann@...gle.com,
        tglx@...utronix.de, peterz@...radead.org, arnd@...db.de,
        ndesaulniers@...gle.com, mingo@...nel.org
Subject: [tip:x86/urgent] x86/boot: #undef memcpy() et al in string.c

Commit-ID:  18d5e6c34a8eda438d5ad8b3b15f42dab01bf05d
Gitweb:     http://git.kernel.org/tip/18d5e6c34a8eda438d5ad8b3b15f42dab01bf05d
Author:     Michael Davidson <md@...gle.com>
AuthorDate: Mon, 24 Jul 2017 16:51:55 -0700
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 25 Jul 2017 11:13:55 +0200

x86/boot: #undef memcpy() et al in string.c

undef memcpy() and friends in boot/string.c so that the functions
defined here will have the correct names, otherwise we end up
up trying to redefine __builtin_memcpy() etc.

Surprisingly, GCC allows this (and, helpfully, discards the
__builtin_ prefix from the function name when compiling it),
but clang does not.

Adding these #undef's appears to preserve what I assume was
the original intent of the code.

Signed-off-by: Michael Davidson <md@...gle.com>
Signed-off-by: Matthias Kaehlcke <mka@...omium.org>
Acked-by: H. Peter Anvin <hpa@...or.com>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Bernhard.Rosenkranzer@...aro.org
Cc: Greg Hackmann <ghackmann@...gle.com>
Cc: Kees Cook <keescook@...omium.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Nick Desaulniers <ndesaulniers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/20170724235155.79255-1-mka@chromium.org
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/boot/string.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/arch/x86/boot/string.c b/arch/x86/boot/string.c
index 630e366..16f4912 100644
--- a/arch/x86/boot/string.c
+++ b/arch/x86/boot/string.c
@@ -16,6 +16,15 @@
 #include "ctype.h"
 #include "string.h"
 
+/*
+ * Undef these macros so that the functions that we provide
+ * here will have the correct names regardless of how string.h
+ * may have chosen to #define them.
+ */
+#undef memcpy
+#undef memset
+#undef memcmp
+
 int memcmp(const void *s1, const void *s2, size_t len)
 {
 	bool diff;