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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/x86/include/asm/cmpxchg_32.h
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/x86/include/asm/cmpxchg_32.h')
-rw-r--r--kernel/arch/x86/include/asm/cmpxchg_32.h114
1 files changed, 114 insertions, 0 deletions
diff --git a/kernel/arch/x86/include/asm/cmpxchg_32.h b/kernel/arch/x86/include/asm/cmpxchg_32.h
new file mode 100644
index 000000000..f7e142926
--- /dev/null
+++ b/kernel/arch/x86/include/asm/cmpxchg_32.h
@@ -0,0 +1,114 @@
+#ifndef _ASM_X86_CMPXCHG_32_H
+#define _ASM_X86_CMPXCHG_32_H
+
+/*
+ * Note: if you use set64_bit(), __cmpxchg64(), or their variants, you
+ * you need to test for the feature in boot_cpu_data.
+ */
+
+/*
+ * CMPXCHG8B only writes to the target if we had the previous
+ * value in registers, otherwise it acts as a read and gives us the
+ * "new previous" value. That is why there is a loop. Preloading
+ * EDX:EAX is a performance optimization: in the common case it means
+ * we need only one locked operation.
+ *
+ * A SIMD/3DNOW!/MMX/FPU 64-bit store here would require at the very
+ * least an FPU save and/or %cr0.ts manipulation.
+ *
+ * cmpxchg8b must be used with the lock prefix here to allow the
+ * instruction to be executed atomically. We need to have the reader
+ * side to see the coherent 64bit value.
+ */
+static inline void set_64bit(volatile u64 *ptr, u64 value)
+{
+ u32 low = value;
+ u32 high = value >> 32;
+ u64 prev = *ptr;
+
+ asm volatile("\n1:\t"
+ LOCK_PREFIX "cmpxchg8b %0\n\t"
+ "jnz 1b"
+ : "=m" (*ptr), "+A" (prev)
+ : "b" (low), "c" (high)
+ : "memory");
+}
+
+#ifdef CONFIG_X86_CMPXCHG64
+#define cmpxchg64(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \
+ (unsigned long long)(n)))
+#define cmpxchg64_local(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg64_local((ptr), (unsigned long long)(o), \
+ (unsigned long long)(n)))
+#endif
+
+static inline u64 __cmpxchg64(volatile u64 *ptr, u64 old, u64 new)
+{
+ u64 prev;
+ asm volatile(LOCK_PREFIX "cmpxchg8b %1"
+ : "=A" (prev),
+ "+m" (*ptr)
+ : "b" ((u32)new),
+ "c" ((u32)(new >> 32)),
+ "0" (old)
+ : "memory");
+ return prev;
+}
+
+static inline u64 __cmpxchg64_local(volatile u64 *ptr, u64 old, u64 new)
+{
+ u64 prev;
+ asm volatile("cmpxchg8b %1"
+ : "=A" (prev),
+ "+m" (*ptr)
+ : "b" ((u32)new),
+ "c" ((u32)(new >> 32)),
+ "0" (old)
+ : "memory");
+ return prev;
+}
+
+#ifndef CONFIG_X86_CMPXCHG64
+/*
+ * Building a kernel capable running on 80386 and 80486. It may be necessary
+ * to simulate the cmpxchg8b on the 80386 and 80486 CPU.
+ */
+
+#define cmpxchg64(ptr, o, n) \
+({ \
+ __typeof__(*(ptr)) __ret; \
+ __typeof__(*(ptr)) __old = (o); \
+ __typeof__(*(ptr)) __new = (n); \
+ alternative_io(LOCK_PREFIX_HERE \
+ "call cmpxchg8b_emu", \
+ "lock; cmpxchg8b (%%esi)" , \
+ X86_FEATURE_CX8, \
+ "=A" (__ret), \
+ "S" ((ptr)), "0" (__old), \
+ "b" ((unsigned int)__new), \
+ "c" ((unsigned int)(__new>>32)) \
+ : "memory"); \
+ __ret; })
+
+
+#define cmpxchg64_local(ptr, o, n) \
+({ \
+ __typeof__(*(ptr)) __ret; \
+ __typeof__(*(ptr)) __old = (o); \
+ __typeof__(*(ptr)) __new = (n); \
+ alternative_io("call cmpxchg8b_emu", \
+ "cmpxchg8b (%%esi)" , \
+ X86_FEATURE_CX8, \
+ "=A" (__ret), \
+ "S" ((ptr)), "0" (__old), \
+ "b" ((unsigned int)__new), \
+ "c" ((unsigned int)(__new>>32)) \
+ : "memory"); \
+ __ret; })
+
+#endif
+
+#define system_has_cmpxchg_double() cpu_has_cx8
+
+#endif /* _ASM_X86_CMPXCHG_32_H */