linux-kernel - [PATCHv2 5/6] jump label: detect %c support for ARM

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Date:	Sat, 28 Jan 2012 19:05:24 +0530
From:	Rabin Vincent <rabin@....in>
To:	linux-arm-kernel@...ts.infradead.org
Cc:	Rabin Vincent <rabin@....in>, Jason Baron <jbaron@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCHv2 5/6] jump label: detect %c support for ARM

Some versions of ARM GCC which do support asm goto, have problems
handling the the %c specifier.  Since we need the %c to support jump
labels on ARM, detect that too in the asm goto detection script to avoid
build errors with these versions.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48637

Cc: Jason Baron <jbaron@...hat.com>
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Rabin Vincent <rabin@....in>
---
 scripts/gcc-goto.sh |   18 +++++++++++++++++-
 1 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/scripts/gcc-goto.sh b/scripts/gcc-goto.sh
index 98cffcb..9b744de 100644
--- a/scripts/gcc-goto.sh
+++ b/scripts/gcc-goto.sh
@@ -2,4 +2,20 @@
 # Test for gcc 'asm goto' support
 # Copyright (C) 2010, Jason Baron <jbaron@...hat.com>
 
-echo "int main(void) { entry: asm goto (\"\"::::entry); return 0; }" | $@ -x c - -c -o /dev/null >/dev/null 2>&1 && echo "y"
+cat << "END" | $@ -x c - -c -o /dev/null >/dev/null 2>&1 && echo "y"
+int main(void)
+{
+#ifdef __arm__
+	/*
+	 * Not related to asm goto, but used by jump label
+	 * and broken on some ARM GCC versions (see GCC Bug 48637).
+	 */
+	static struct { int dummy; int state; } tp;
+	asm ("@ %c0" :: "i" (&tp.state));
+#endif
+
+entry:
+	asm goto ("" :::: entry);
+	return 0;
+}
+END
-- 
1.7.8.3

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