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Message-Id: <cdab58b7ca6d3d4e74b84d2416257ec4287b123b.1314221624.git.jeremy.fitzhardinge@citrix.com>
Date: Wed, 24 Aug 2011 14:37:01 -0700
From: Jeremy Fitzhardinge <jeremy@...p.org>
To: "H. Peter Anvin" <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...e.hu>,
the arch/x86 maintainers <x86@...nel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Nick Piggin <npiggin@...nel.dk>,
Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Subject: [PATCH 04/12] x86/cmpxchg: unify cmpxchg into cmpxchg.h
From: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Everything that's actually common between 32 and 64-bit is moved into
cmpxchg.h.
xchg/cmpxchg will fail with a link error if they're passed an
unsupported size (which includes 64-bit args on 32-bit systems).
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
---
arch/x86/include/asm/cmpxchg.h | 155 +++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/cmpxchg_32.h | 113 ---------------------------
arch/x86/include/asm/cmpxchg_64.h | 131 -------------------------------
3 files changed, 155 insertions(+), 244 deletions(-)
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h
index a460fa0..efe3ec7 100644
--- a/arch/x86/include/asm/cmpxchg.h
+++ b/arch/x86/include/asm/cmpxchg.h
@@ -1,5 +1,160 @@
+#ifndef ASM_X86_CMPXCHG_H
+#define ASM_X86_CMPXCHG_H
+
+#include <asm/alternative.h> /* Provides LOCK_PREFIX */
+
+/* Non-existant functions to indicate usage errors at link time. */
+extern void __xchg_wrong_size(void);
+extern void __cmpxchg_wrong_size(void);
+
+/*
+ * Constants for operation sizes. On 32-bit, the 64-bit size it set to
+ * -1 because sizeof will never return -1, thereby making those switch
+ * case statements guaranteeed dead code which the compiler will
+ * eliminate, and allowing the "missing symbol in the default case" to
+ * indicate a usage error.
+ */
+#define __X86_CASE_B 1
+#define __X86_CASE_W 2
+#define __X86_CASE_L 4
+#ifdef CONFIG_64BIT
+#define __X86_CASE_Q 8
+#else
+#define __X86_CASE_Q -1 /* sizeof will never return -1 */
+#endif
+
+/*
+ * Note: no "lock" prefix even on SMP: xchg always implies lock anyway.
+ * Since this is generally used to protect other memory information, we
+ * use "asm volatile" and "memory" clobbers to prevent gcc from moving
+ * information around.
+ */
+#define __xchg(x, ptr, size) \
+({ \
+ __typeof(*(ptr)) __x = (x); \
+ switch (size) { \
+ case __X86_CASE_B: \
+ { \
+ volatile u8 *__ptr = (volatile u8 *)(ptr); \
+ asm volatile("xchgb %0,%1" \
+ : "=q" (__x), "+m" (*__ptr) \
+ : "0" (__x) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_W: \
+ { \
+ volatile u16 *__ptr = (volatile u16 *)(ptr); \
+ asm volatile("xchgw %0,%1" \
+ : "=r" (__x), "+m" (*__ptr) \
+ : "0" (__x) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_L: \
+ { \
+ volatile u32 *__ptr = (volatile u32 *)(ptr); \
+ asm volatile("xchgl %0,%1" \
+ : "=r" (__x), "+m" (*__ptr) \
+ : "0" (__x) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_Q: \
+ { \
+ volatile u64 *__ptr = (volatile u64 *)(ptr); \
+ asm volatile("xchgq %0,%1" \
+ : "=r" (__x), "+m" (*__ptr) \
+ : "0" (__x) \
+ : "memory"); \
+ break; \
+ } \
+ default: \
+ __xchg_wrong_size(); \
+ } \
+ __x; \
+})
+
+#define xchg(ptr, v) \
+ __xchg((v), (ptr), sizeof(*ptr))
+
+/*
+ * 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 __X86_CASE_B: \
+ { \
+ volatile u8 *__ptr = (volatile u8 *)(ptr); \
+ asm volatile(lock "cmpxchgb %2,%1" \
+ : "=a" (__ret), "+m" (*__ptr) \
+ : "q" (__new), "0" (__old) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_W: \
+ { \
+ volatile u16 *__ptr = (volatile u16 *)(ptr); \
+ asm volatile(lock "cmpxchgw %2,%1" \
+ : "=a" (__ret), "+m" (*__ptr) \
+ : "r" (__new), "0" (__old) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_L: \
+ { \
+ volatile u32 *__ptr = (volatile u32 *)(ptr); \
+ asm volatile(lock "cmpxchgl %2,%1" \
+ : "=a" (__ret), "+m" (*__ptr) \
+ : "r" (__new), "0" (__old) \
+ : "memory"); \
+ break; \
+ } \
+ case __X86_CASE_Q: \
+ { \
+ volatile u64 *__ptr = (volatile u64 *)(ptr); \
+ asm volatile(lock "cmpxchgq %2,%1" \
+ : "=a" (__ret), "+m" (*__ptr) \
+ : "r" (__new), "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_32
# include "cmpxchg_32.h"
#else
# include "cmpxchg_64.h"
#endif
+
+#ifdef __HAVE_ARCH_CMPXCHG
+#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
+
+#endif /* ASM_X86_CMPXCHG_H */
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index 0ef9b82..3b573f6 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -1,62 +1,11 @@
#ifndef _ASM_X86_CMPXCHG_32_H
#define _ASM_X86_CMPXCHG_32_H
-#include <asm/alternative.h> /* Provides LOCK_PREFIX */
-
/*
* Note: if you use set64_bit(), __cmpxchg64(), or their variants, you
* you need to test for the feature in boot_cpu_data.
*/
-extern void __xchg_wrong_size(void);
-extern void __cmpxchg_wrong_size(void);
-
-/*
- * Note: no "lock" prefix even on SMP: xchg always implies lock anyway.
- * Since this is generally used to protect other memory information, we
- * use "asm volatile" and "memory" clobbers to prevent gcc from moving
- * information around.
- */
-#define __xchg(x, ptr, size) \
-({ \
- __typeof(*(ptr)) __x = (x); \
- switch (size) { \
- case 1: \
- { \
- volatile u8 *__ptr = (volatile u8 *)(ptr); \
- asm volatile("xchgb %0,%1" \
- : "=q" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- case 2: \
- { \
- volatile u16 *__ptr = (volatile u16 *)(ptr); \
- asm volatile("xchgw %0,%1" \
- : "=r" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- case 4: \
- { \
- volatile u32 *__ptr = (volatile u32 *)(ptr); \
- asm volatile("xchgl %0,%1" \
- : "=r" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- default: \
- __xchg_wrong_size(); \
- } \
- __x; \
-})
-
-#define xchg(ptr, v) \
- __xchg((v), (ptr), sizeof(*ptr))
-
/*
* CMPXCHG8B only writes to the target if we had the previous
* value in registers, otherwise it acts as a read and gives us the
@@ -85,70 +34,8 @@ static inline void set_64bit(volatile u64 *ptr, u64 value)
: "memory");
}
-/*
- * 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: \
- { \
- volatile u8 *__ptr = (volatile u8 *)(ptr); \
- asm volatile(lock "cmpxchgb %2,%1" \
- : "=a" (__ret), "+m" (*__ptr) \
- : "q" (__new), "0" (__old) \
- : "memory"); \
- break; \
- } \
- case 2: \
- { \
- volatile u16 *__ptr = (volatile u16 *)(ptr); \
- asm volatile(lock "cmpxchgw %2,%1" \
- : "=a" (__ret), "+m" (*__ptr) \
- : "r" (__new), "0" (__old) \
- : "memory"); \
- break; \
- } \
- case 4: \
- { \
- volatile u32 *__ptr = (volatile u32 *)(ptr); \
- asm volatile(lock "cmpxchgl %2,%1" \
- : "=a" (__ret), "+m" (*__ptr) \
- : "r" (__new), "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, 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
diff --git a/arch/x86/include/asm/cmpxchg_64.h b/arch/x86/include/asm/cmpxchg_64.h
index aeaa610..9d6c147 100644
--- a/arch/x86/include/asm/cmpxchg_64.h
+++ b/arch/x86/include/asm/cmpxchg_64.h
@@ -1,66 +1,6 @@
#ifndef _ASM_X86_CMPXCHG_64_H
#define _ASM_X86_CMPXCHG_64_H
-#include <asm/alternative.h> /* Provides LOCK_PREFIX */
-
-extern void __xchg_wrong_size(void);
-extern void __cmpxchg_wrong_size(void);
-
-/*
- * Note: no "lock" prefix even on SMP: xchg always implies lock anyway.
- * Since this is generally used to protect other memory information, we
- * use "asm volatile" and "memory" clobbers to prevent gcc from moving
- * information around.
- */
-#define __xchg(x, ptr, size) \
-({ \
- __typeof(*(ptr)) __x = (x); \
- switch (size) { \
- case 1: \
- { \
- volatile u8 *__ptr = (volatile u8 *)(ptr); \
- asm volatile("xchgb %0,%1" \
- : "=q" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- case 2: \
- { \
- volatile u16 *__ptr = (volatile u16 *)(ptr); \
- asm volatile("xchgw %0,%1" \
- : "=r" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- case 4: \
- { \
- volatile u32 *__ptr = (volatile u32 *)(ptr); \
- asm volatile("xchgl %0,%1" \
- : "=r" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- case 8: \
- { \
- volatile u64 *__ptr = (volatile u64 *)(ptr); \
- asm volatile("xchgq %0,%1" \
- : "=r" (__x), "+m" (*__ptr) \
- : "0" (__x) \
- : "memory"); \
- break; \
- } \
- default: \
- __xchg_wrong_size(); \
- } \
- __x; \
-})
-
-#define xchg(ptr, v) \
- __xchg((v), (ptr), sizeof(*ptr))
-
static inline void set_64bit(volatile u64 *ptr, u64 val)
{
*ptr = val;
@@ -68,77 +8,6 @@ static inline void set_64bit(volatile u64 *ptr, u64 val)
#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: \
- { \
- volatile u8 *__ptr = (volatile u8 *)(ptr); \
- asm volatile(lock "cmpxchgb %2,%1" \
- : "=a" (__ret), "+m" (*__ptr) \
- : "q" (__new), "0" (__old) \
- : "memory"); \
- break; \
- } \
- case 2: \
- { \
- volatile u16 *__ptr = (volatile u16 *)(ptr); \
- asm volatile(lock "cmpxchgw %2,%1" \
- : "=a" (__ret), "+m" (*__ptr) \
- : "r" (__new), "0" (__old) \
- : "memory"); \
- break; \
- } \
- case 4: \
- { \
- volatile u32 *__ptr = (volatile u32 *)(ptr); \
- asm volatile(lock "cmpxchgl %2,%1" \
- : "=a" (__ret), "+m" (*__ptr) \
- : "r" (__new), "0" (__old) \
- : "memory"); \
- break; \
- } \
- case 8: \
- { \
- volatile u64 *__ptr = (volatile u64 *)(ptr); \
- asm volatile(lock "cmpxchgq %2,%1" \
- : "=a" (__ret), "+m" (*__ptr) \
- : "r" (__new), "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), "")
-
-#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 cmpxchg64(ptr, o, n) \
({ \
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
--
1.7.6
--
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