From 1451a958347f5e683c63466cd7dfb893c1651f19 Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Sat, 18 Jul 2015 18:46:24 +0200
Subject: kern/lock: use compiler built-in functions to get return address

* kern/lock.c (struct simple_locks_info): Fix type of `ra'.
(simple_lock, simple_lock_try): Use compiler built-in functions to get
return address.
---
 kern/lock.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/kern/lock.c b/kern/lock.c
index fb5e3441..3c74fec8 100644
--- a/kern/lock.c
+++ b/kern/lock.c
@@ -133,7 +133,7 @@ unsigned int simple_locks_taken = 0;
 
 struct simple_locks_info {
 	simple_lock_t l;
-	unsigned int ra;
+	void *ra;
 } simple_locks_info[NSLINFO];
 
 void check_simple_locks(void)
@@ -161,10 +161,8 @@ void simple_lock(
 
 	info = &simple_locks_info[simple_locks_taken++];
 	info->l = l;
-	/* XXX we want our return address, if possible */
-#if defined(__i386__)
-	info->ra = *((unsigned long *)&l - 1);
-#endif	/* i386 */
+	info->ra =
+		__builtin_extract_return_addr (__builtin_return_address (0));
 }
 
 boolean_t simple_lock_try(
@@ -179,10 +177,8 @@ boolean_t simple_lock_try(
 
 	info = &simple_locks_info[simple_locks_taken++];
 	info->l = l;
-	/* XXX we want our return address, if possible */
-#if defined(__i386__)
-	info->ra = *((unsigned long *)&l - 1);
-#endif	/* i386 */
+	info->ra =
+		__builtin_extract_return_addr (__builtin_return_address (0));
 
 	return TRUE;
 }
-- 
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