1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
From de01f17a2cb88dc5ff53cc321342b888c33b120a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Minier?= <lool@dooz.org>
Date: Thu, 11 Feb 2010 17:42:33 +0100
Subject: [PATCH] Detect and use GCC atomic builtins for locking
---
configure | 17 +++++++++++++++++
qemu-lock.h | 13 +++++++++++++
2 files changed, 30 insertions(+), 0 deletions(-)
Upstream-Status: Pending
Index: qemu-0.14.0/configure
===================================================================
--- qemu-0.14.0.orig/configure
+++ qemu-0.14.0/configure
@@ -2243,6 +2243,20 @@ fi
##########################################
##########################################
+# check if we have gcc atomic built-ins
+gcc_atomic_builtins=no
+cat > $TMPC << EOF
+int main(void) {
+ int i;
+ __sync_lock_test_and_set(&i, 1);
+ __sync_lock_release(&i);
+}
+EOF
+if compile_prog "" ""; then
+ gcc_atomic_builtins=yes
+fi
+
+##########################################
# check if we have fdatasync
fdatasync=no
@@ -2731,6 +2745,9 @@ fi
if test "$gcc_attribute_warn_unused_result" = "yes" ; then
echo "CONFIG_GCC_ATTRIBUTE_WARN_UNUSED_RESULT=y" >> $config_host_mak
fi
+if test "$gcc_atomic_builtins" = "yes" ; then
+ echo "CONFIG_GCC_ATOMIC_BUILTINS=y" >> $config_host_mak
+fi
if test "$fdatasync" = "yes" ; then
echo "CONFIG_FDATASYNC=y" >> $config_host_mak
fi
Index: qemu-0.14.0/qemu-lock.h
===================================================================
--- qemu-0.14.0.orig/qemu-lock.h
+++ qemu-0.14.0/qemu-lock.h
@@ -33,6 +33,14 @@
#else
+#ifdef CONFIG_GCC_ATOMIC_BUILTINS
+typedef int spinlock_t;
+
+#define SPIN_LOCK_UNLOCKED 0
+
+#define resetlock(p) __sync_lock_release((p))
+#else /* CONFIG_GCC_ATOMIC_BUILTINS */
+
#if defined(__hppa__)
typedef int spinlock_t[4];
@@ -56,7 +64,11 @@ static inline void resetlock (spinlock_t
}
#endif
+#endif /* !CONFIG_GCC_ATOMIC_BUILTINS */
+#ifdef CONFIG_GCC_ATOMIC_BUILTINS
+#define testandset(p) __sync_lock_test_and_set((p), 1)
+#else /* CONFIG_GCC_ATOMIC_BUILTINS */
#if defined(_ARCH_PPC)
static inline int testandset (int *p)
{
@@ -213,6 +225,7 @@ static inline int testandset (int *p)
#else
#error unimplemented CPU support
#endif
+#endif /* !CONFIG_GCC_ATOMIC_BUILTINS */
#if defined(CONFIG_USER_ONLY)
static inline void spin_lock(spinlock_t *lock)
|
