kernel26-xen/patches-2.6.25-r1/1030-2.6.25-xen-x86_64-Add-sync_cmpxchg.patch

From 82328d0ef4a109e66264e70692fec273b201ee41 Mon Sep 17 00:00:00 2001
From: Eduardo Habkost <ehabkost@Rawhide-64.localdomain>
Date: Tue, 27 Nov 2007 18:08:41 -0200
Subject: [PATCH] x86_64: Add sync_cmpxchg()

Add a sync_cmpxchg() for x86_64, including a sync_cmpxchg64()
implementation.

Needed for Xen's grant table implementation.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>
---
 include/asm-x86/cmpxchg_64.h |   47 ++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 47 insertions(+), 0 deletions(-)

diff --git a/include/asm-x86/cmpxchg_64.h b/include/asm-x86/cmpxchg_64.h
index 56f5b41..1556f64 100644
--- a/include/asm-x86/cmpxchg_64.h
+++ b/include/asm-x86/cmpxchg_64.h
@@ -91,6 +91,45 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
 	return old;
 }
 
+/*
+ * Always use locked operations when touching memory shared with a
+ * hypervisor, since the system may be SMP even if the guest kernel
+ * isn't.
+ */
+static inline unsigned long __sync_cmpxchg(volatile void *ptr,
+					    unsigned long old,
+					    unsigned long new, int size)
+{
+	unsigned long prev;
+	switch (size) {
+	case 1:
+		__asm__ __volatile__("lock; cmpxchgb %b1,%2"
+				     : "=a"(prev)
+				     : "q"(new), "m"(*__xg(ptr)), "0"(old)
+				     : "memory");
+		return prev;
+	case 2:
+		__asm__ __volatile__("lock; cmpxchgw %w1,%2"
+				     : "=a"(prev)
+				     : "r"(new), "m"(*__xg(ptr)), "0"(old)
+				     : "memory");
+		return prev;
+	case 4:
+		__asm__ __volatile__("lock; cmpxchgl %k1,%2"
+				     : "=a"(prev)
+				     : "r"(new), "m"(*__xg(ptr)), "0"(old)
+				     : "memory");
+		return prev;
+	case 8:
+		__asm__ __volatile__("lock; cmpxchgq %1,%2"
+				     : "=a"(prev)
+				     : "r"(new), "m"(*__xg(ptr)), "0"(old)
+				     : "memory");
+		return prev;
+	}
+	return old;
+}
+
 static inline unsigned long __cmpxchg_local(volatile void *ptr,
 			unsigned long old, unsigned long new, int size)
 {
@@ -132,6 +171,14 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr,
 	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
 	cmpxchg((ptr), (o), (n));					\
   })
+#define sync_cmpxchg(ptr, o, n)						\
+	((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o),	\
+					(unsigned long)(n), sizeof(*(ptr))))
+#define sync_cmpxchg64(ptr, o, n)					\
+  ({									\
+	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
+	sync_cmpxchg((ptr), (o), (n));					\
+  })
 #define cmpxchg_local(ptr, o, n)					\
 	((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o),	\
 					(unsigned long)(n), sizeof(*(ptr))))
-- 
1.5.4.1

1	niro	606	From 82328d0ef4a109e66264e70692fec273b201ee41 Mon Sep 17 00:00:00 2001
2			From: Eduardo Habkost <ehabkost@Rawhide-64.localdomain>
3			Date: Tue, 27 Nov 2007 18:08:41 -0200
4			Subject: [PATCH] x86_64: Add sync_cmpxchg()
5
6			Add a sync_cmpxchg() for x86_64, including a sync_cmpxchg64()
7			implementation.
8
9			Needed for Xen's grant table implementation.
10
11			Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
12			Signed-off-by: Mark McLoughlin <markmc@redhat.com>
13			---
14			include/asm-x86/cmpxchg_64.h \| 47 ++++++++++++++++++++++++++++++++++++++++++
15			1 files changed, 47 insertions(+), 0 deletions(-)
16
17			diff --git a/include/asm-x86/cmpxchg_64.h b/include/asm-x86/cmpxchg_64.h
18			index 56f5b41..1556f64 100644
19			--- a/include/asm-x86/cmpxchg_64.h
20			+++ b/include/asm-x86/cmpxchg_64.h
21			@@ -91,6 +91,45 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
22			return old;
23			}
24
25			+/*
26			+ * Always use locked operations when touching memory shared with a
27			+ * hypervisor, since the system may be SMP even if the guest kernel
28			+ * isn't.
29			+ */
30			+static inline unsigned long __sync_cmpxchg(volatile void *ptr,
31			+ unsigned long old,
32			+ unsigned long new, int size)
33			+{
34			+ unsigned long prev;
35			+ switch (size) {
36			+ case 1:
37			+ __asm__ __volatile__("lock; cmpxchgb %b1,%2"
38			+ : "=a"(prev)
39			+ : "q"(new), "m"(*__xg(ptr)), "0"(old)
40			+ : "memory");
41			+ return prev;
42			+ case 2:
43			+ __asm__ __volatile__("lock; cmpxchgw %w1,%2"
44			+ : "=a"(prev)
45			+ : "r"(new), "m"(*__xg(ptr)), "0"(old)
46			+ : "memory");
47			+ return prev;
48			+ case 4:
49			+ __asm__ __volatile__("lock; cmpxchgl %k1,%2"
50			+ : "=a"(prev)
51			+ : "r"(new), "m"(*__xg(ptr)), "0"(old)
52			+ : "memory");
53			+ return prev;
54			+ case 8:
55			+ __asm__ __volatile__("lock; cmpxchgq %1,%2"
56			+ : "=a"(prev)
57			+ : "r"(new), "m"(*__xg(ptr)), "0"(old)
58			+ : "memory");
59			+ return prev;
60			+ }
61			+ return old;
62			+}
63			+
64			static inline unsigned long __cmpxchg_local(volatile void *ptr,
65			unsigned long old, unsigned long new, int size)
66			{
67			@@ -132,6 +171,14 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr,
68			BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
69			cmpxchg((ptr), (o), (n)); \
70			})
71			+#define sync_cmpxchg(ptr, o, n) \
72			+ ((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \
73			+ (unsigned long)(n), sizeof(*(ptr))))
74			+#define sync_cmpxchg64(ptr, o, n) \
75			+ ({ \
76			+ BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
77			+ sync_cmpxchg((ptr), (o), (n)); \
78			+ })
79			#define cmpxchg_local(ptr, o, n) \
80			((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
81			(unsigned long)(n), sizeof(*(ptr))))
82			--
83			1.5.4.1
84