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From: Michael Davidson <md@google.com>
To: "H . Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>
Cc: Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Michael Davidson <md@google.com>
Subject: [PATCH 1/2] x86, boot: #undef memcpy etc in string.c
Date: Wed, 15 Mar 2017 14:48:20 -0700	[thread overview]
Message-ID: <20170315214821.127170-1-md@google.com> (raw)

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@google.com>
---
 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 5457b02fc050..b40266850869 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;
-- 
2.12.0.367.g23dc2f6d3c-goog

             reply	other threads:[~2017-03-15 21:48 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-15 21:48 Michael Davidson [this message]
2017-03-15 21:48 ` [PATCH 2/2] x86, boot: Use regparm=0 for memcpy and memset when using clang Michael Davidson
2017-03-16  7:46   ` Ingo Molnar
2017-03-16 15:21     ` Michael Davidson

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