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Date: Fri, 9 Oct 2009 14:23:05 GMT
From: tip-bot for Peter Zijlstra <a.p.zijlstra@...llo.nl>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
torvalds@...ux-foundation.org, a.p.zijlstra@...llo.nl,
tglx@...utronix.de, mingo@...e.hu
Subject: [tip:x86/asm] x86: Generate cmpxchg build failures
Commit-ID: f3834b9ef68067199486740b31f691afb14dbdf5
Gitweb: http://git.kernel.org/tip/f3834b9ef68067199486740b31f691afb14dbdf5
Author: Peter Zijlstra <a.p.zijlstra@...llo.nl>
AuthorDate: Fri, 9 Oct 2009 10:12:46 +0200
Committer: Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 9 Oct 2009 15:57:00 +0200
x86: Generate cmpxchg build failures
Rework the x86 cmpxchg() implementation to generate build failures
when used on improper types.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Acked-by: Linus Torvalds <torvalds@...ux-foundation.org>
LKML-Reference: <1254771187.21044.22.camel@...top>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
arch/x86/include/asm/cmpxchg_32.h | 218 ++++++++++++++---------------------
arch/x86/include/asm/cmpxchg_64.h | 234 ++++++++++++++----------------------
2 files changed, 177 insertions(+), 275 deletions(-)
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index 82ceb78..5371174 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -8,14 +8,50 @@
* you need to test for the feature in boot_cpu_data.
*/
-#define xchg(ptr, v) \
- ((__typeof__(*(ptr)))__xchg((unsigned long)(v), (ptr), sizeof(*(ptr))))
+extern void __xchg_wrong_size(void);
+
+/*
+ * Note: no "lock" prefix even on SMP: xchg always implies lock anyway
+ * Note 2: xchg has side effect, so that attribute volatile is necessary,
+ * but generally the primitive is invalid, *ptr is output argument. --ANK
+ */
struct __xchg_dummy {
unsigned long a[100];
};
#define __xg(x) ((struct __xchg_dummy *)(x))
+#define __xchg(x, ptr, size) \
+({ \
+ __typeof(*(ptr)) __x = (x); \
+ switch (size) { \
+ case 1: \
+ asm volatile("xchgb %b0,%1" \
+ : "=q" (__x) \
+ : "m" (*__xg(ptr)), "0" (__x) \
+ : "memory"); \
+ break; \
+ case 2: \
+ asm volatile("xchgw %w0,%1" \
+ : "=r" (__x) \
+ : "m" (*__xg(ptr)), "0" (__x) \
+ : "memory"); \
+ break; \
+ case 4: \
+ asm volatile("xchgl %0,%1" \
+ : "=r" (__x) \
+ : "m" (*__xg(ptr)), "0" (__x) \
+ : "memory"); \
+ break; \
+ default: \
+ __xchg_wrong_size(); \
+ } \
+ __x; \
+})
+
+#define xchg(ptr, v) \
+ __xchg((v), (ptr), sizeof(*ptr))
+
/*
* The semantics of XCHGCMP8B are a bit strange, this is why
* there is a loop and the loading of %%eax and %%edx has to
@@ -71,57 +107,63 @@ static inline void __set_64bit_var(unsigned long long *ptr,
(unsigned int)((value) >> 32)) \
: __set_64bit(ptr, ll_low((value)), ll_high((value))))
-/*
- * Note: no "lock" prefix even on SMP: xchg always implies lock anyway
- * Note 2: xchg has side effect, so that attribute volatile is necessary,
- * but generally the primitive is invalid, *ptr is output argument. --ANK
- */
-static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
- int size)
-{
- switch (size) {
- case 1:
- asm volatile("xchgb %b0,%1"
- : "=q" (x)
- : "m" (*__xg(ptr)), "0" (x)
- : "memory");
- break;
- case 2:
- asm volatile("xchgw %w0,%1"
- : "=r" (x)
- : "m" (*__xg(ptr)), "0" (x)
- : "memory");
- break;
- case 4:
- asm volatile("xchgl %0,%1"
- : "=r" (x)
- : "m" (*__xg(ptr)), "0" (x)
- : "memory");
- break;
- }
- return x;
-}
+extern void __cmpxchg_wrong_size(void);
/*
* Atomic compare and exchange. Compare OLD with MEM, if identical,
* store NEW in MEM. Return the initial value in MEM. Success is
* indicated by comparing RETURN with OLD.
*/
+#define __raw_cmpxchg(ptr, old, new, size, lock) \
+({ \
+ __typeof__(*(ptr)) __ret; \
+ __typeof__(*(ptr)) __old = (old); \
+ __typeof__(*(ptr)) __new = (new); \
+ switch (size) { \
+ case 1: \
+ asm volatile(lock "cmpxchgb %b1,%2" \
+ : "=a"(__ret) \
+ : "q"(__new), "m"(*__xg(ptr)), "0"(__old) \
+ : "memory"); \
+ break; \
+ case 2: \
+ asm volatile(lock "cmpxchgw %w1,%2" \
+ : "=a"(__ret) \
+ : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
+ : "memory"); \
+ break; \
+ case 4: \
+ asm volatile(lock "cmpxchgl %1,%2" \
+ : "=a"(__ret) \
+ : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
+ : "memory"); \
+ break; \
+ default: \
+ __cmpxchg_wrong_size(); \
+ } \
+ __ret; \
+})
+
+#define __cmpxchg(ptr, old, new, size) \
+ __raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)
+
+#define __sync_cmpxchg(ptr, old, new, size) \
+ __raw_cmpxchg((ptr), (old), (new), (size), "lock; ")
+
+#define __cmpxchg_local(ptr, old, new, size) \
+ __raw_cmpxchg((ptr), (old), (new), (size), "")
#ifdef CONFIG_X86_CMPXCHG
#define __HAVE_ARCH_CMPXCHG 1
-#define cmpxchg(ptr, o, n) \
- ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
- (unsigned long)(n), \
- sizeof(*(ptr))))
-#define sync_cmpxchg(ptr, o, n) \
- ((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \
- (unsigned long)(n), \
- sizeof(*(ptr))))
-#define cmpxchg_local(ptr, o, n) \
- ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
- (unsigned long)(n), \
- sizeof(*(ptr))))
+
+#define cmpxchg(ptr, old, new) \
+ __cmpxchg((ptr), (old), (new), sizeof(*ptr))
+
+#define sync_cmpxchg(ptr, old, new) \
+ __sync_cmpxchg((ptr), (old), (new), sizeof(*ptr))
+
+#define cmpxchg_local(ptr, old, new) \
+ __cmpxchg_local((ptr), (old), (new), sizeof(*ptr))
#endif
#ifdef CONFIG_X86_CMPXCHG64
@@ -133,94 +175,6 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
(unsigned long long)(n)))
#endif
-static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
- unsigned long new, int size)
-{
- unsigned long prev;
- switch (size) {
- case 1:
- asm volatile(LOCK_PREFIX "cmpxchgb %b1,%2"
- : "=a"(prev)
- : "q"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 2:
- asm volatile(LOCK_PREFIX "cmpxchgw %w1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 4:
- asm volatile(LOCK_PREFIX "cmpxchgl %1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- }
- 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 %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)
-{
- unsigned long prev;
- switch (size) {
- case 1:
- asm volatile("cmpxchgb %b1,%2"
- : "=a"(prev)
- : "q"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 2:
- asm volatile("cmpxchgw %w1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 4:
- asm volatile("cmpxchgl %1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- }
- return old;
-}
-
static inline unsigned long long __cmpxchg64(volatile void *ptr,
unsigned long long old,
unsigned long long new)
diff --git a/arch/x86/include/asm/cmpxchg_64.h b/arch/x86/include/asm/cmpxchg_64.h
index 52de72e..485ae41 100644
--- a/arch/x86/include/asm/cmpxchg_64.h
+++ b/arch/x86/include/asm/cmpxchg_64.h
@@ -3,9 +3,6 @@
#include <asm/alternative.h> /* Provides LOCK_PREFIX */
-#define xchg(ptr, v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v), \
- (ptr), sizeof(*(ptr))))
-
#define __xg(x) ((volatile long *)(x))
static inline void set_64bit(volatile unsigned long *ptr, unsigned long val)
@@ -15,167 +12,118 @@ static inline void set_64bit(volatile unsigned long *ptr, unsigned long val)
#define _set_64bit set_64bit
+extern void __xchg_wrong_size(void);
+extern void __cmpxchg_wrong_size(void);
+
/*
* Note: no "lock" prefix even on SMP: xchg always implies lock anyway
* Note 2: xchg has side effect, so that attribute volatile is necessary,
* but generally the primitive is invalid, *ptr is output argument. --ANK
*/
-static inline unsigned long __xchg(unsigned long x, volatile void *ptr,
- int size)
-{
- switch (size) {
- case 1:
- asm volatile("xchgb %b0,%1"
- : "=q" (x)
- : "m" (*__xg(ptr)), "0" (x)
- : "memory");
- break;
- case 2:
- asm volatile("xchgw %w0,%1"
- : "=r" (x)
- : "m" (*__xg(ptr)), "0" (x)
- : "memory");
- break;
- case 4:
- asm volatile("xchgl %k0,%1"
- : "=r" (x)
- : "m" (*__xg(ptr)), "0" (x)
- : "memory");
- break;
- case 8:
- asm volatile("xchgq %0,%1"
- : "=r" (x)
- : "m" (*__xg(ptr)), "0" (x)
- : "memory");
- break;
- }
- return x;
-}
+#define __xchg(x, ptr, size) \
+({ \
+ __typeof(*(ptr)) __x = (x); \
+ switch (size) { \
+ case 1: \
+ asm volatile("xchgb %b0,%1" \
+ : "=q" (__x) \
+ : "m" (*__xg(ptr)), "0" (__x) \
+ : "memory"); \
+ break; \
+ case 2: \
+ asm volatile("xchgw %w0,%1" \
+ : "=r" (__x) \
+ : "m" (*__xg(ptr)), "0" (__x) \
+ : "memory"); \
+ break; \
+ case 4: \
+ asm volatile("xchgl %k0,%1" \
+ : "=r" (__x) \
+ : "m" (*__xg(ptr)), "0" (__x) \
+ : "memory"); \
+ break; \
+ case 8: \
+ asm volatile("xchgq %0,%1" \
+ : "=r" (__x) \
+ : "m" (*__xg(ptr)), "0" (__x) \
+ : "memory"); \
+ break; \
+ default: \
+ __xchg_wrong_size(); \
+ } \
+ __x; \
+})
+
+#define xchg(ptr, v) \
+ __xchg((v), (ptr), sizeof(*ptr))
+
+#define __HAVE_ARCH_CMPXCHG 1
/*
* Atomic compare and exchange. Compare OLD with MEM, if identical,
* store NEW in MEM. Return the initial value in MEM. Success is
* indicated by comparing RETURN with OLD.
*/
+#define __raw_cmpxchg(ptr, old, new, size, lock) \
+({ \
+ __typeof__(*(ptr)) __ret; \
+ __typeof__(*(ptr)) __old = (old); \
+ __typeof__(*(ptr)) __new = (new); \
+ switch (size) { \
+ case 1: \
+ asm volatile(lock "cmpxchgb %b1,%2" \
+ : "=a"(__ret) \
+ : "q"(__new), "m"(*__xg(ptr)), "0"(__old) \
+ : "memory"); \
+ break; \
+ case 2: \
+ asm volatile(lock "cmpxchgw %w1,%2" \
+ : "=a"(__ret) \
+ : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
+ : "memory"); \
+ break; \
+ case 4: \
+ asm volatile(lock "cmpxchgl %k1,%2" \
+ : "=a"(__ret) \
+ : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
+ : "memory"); \
+ break; \
+ case 8: \
+ asm volatile(lock "cmpxchgq %1,%2" \
+ : "=a"(__ret) \
+ : "r"(__new), "m"(*__xg(ptr)), "0"(__old) \
+ : "memory"); \
+ break; \
+ default: \
+ __cmpxchg_wrong_size(); \
+ } \
+ __ret; \
+})
-#define __HAVE_ARCH_CMPXCHG 1
+#define __cmpxchg(ptr, old, new, size) \
+ __raw_cmpxchg((ptr), (old), (new), (size), LOCK_PREFIX)
-static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
- unsigned long new, int size)
-{
- unsigned long prev;
- switch (size) {
- case 1:
- asm volatile(LOCK_PREFIX "cmpxchgb %b1,%2"
- : "=a"(prev)
- : "q"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 2:
- asm volatile(LOCK_PREFIX "cmpxchgw %w1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 4:
- asm volatile(LOCK_PREFIX "cmpxchgl %k1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 8:
- asm volatile(LOCK_PREFIX "cmpxchgq %1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- }
- return old;
-}
+#define __sync_cmpxchg(ptr, old, new, size) \
+ __raw_cmpxchg((ptr), (old), (new), (size), "lock; ")
-/*
- * 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 %1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- }
- return old;
-}
+#define __cmpxchg_local(ptr, old, new, size) \
+ __raw_cmpxchg((ptr), (old), (new), (size), "")
-static inline unsigned long __cmpxchg_local(volatile void *ptr,
- unsigned long old,
- unsigned long new, int size)
-{
- unsigned long prev;
- switch (size) {
- case 1:
- asm volatile("cmpxchgb %b1,%2"
- : "=a"(prev)
- : "q"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 2:
- asm volatile("cmpxchgw %w1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 4:
- asm volatile("cmpxchgl %k1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- case 8:
- asm volatile("cmpxchgq %1,%2"
- : "=a"(prev)
- : "r"(new), "m"(*__xg(ptr)), "0"(old)
- : "memory");
- return prev;
- }
- return old;
-}
+#define cmpxchg(ptr, old, new) \
+ __cmpxchg((ptr), (old), (new), sizeof(*ptr))
+
+#define sync_cmpxchg(ptr, old, new) \
+ __sync_cmpxchg((ptr), (old), (new), sizeof(*ptr))
+
+#define cmpxchg_local(ptr, old, new) \
+ __cmpxchg_local((ptr), (old), (new), sizeof(*ptr))
-#define cmpxchg(ptr, o, n) \
- ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
- (unsigned long)(n), sizeof(*(ptr))))
#define cmpxchg64(ptr, o, n) \
({ \
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
cmpxchg((ptr), (o), (n)); \
})
-#define cmpxchg_local(ptr, o, n) \
- ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
- (unsigned long)(n), \
- sizeof(*(ptr))))
-#define sync_cmpxchg(ptr, o, n) \
- ((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \
- (unsigned long)(n), \
- sizeof(*(ptr))))
+
#define cmpxchg64_local(ptr, o, n) \
({ \
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
--
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