1 files changed, 48 insertions, 0 deletions

diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 3788f4649db..260ac7af1fd 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -451,6 +451,26 @@ do {									\
 #define irqsafe_cpu_cmpxchg_4(pcp, oval, nval)  percpu_cmpxchg_op(pcp, oval, nval)
 #endif /* !CONFIG_M386 */
 
+#ifdef CONFIG_X86_CMPXCHG64
+#define percpu_cmpxchg8b_double(pcp1, o1, o2, n1, n2)                   \
+({                                                                      \
+        char __ret;                                                     \
+        typeof(o1) __o1 = o1;                                           \
+        typeof(o1) __n1 = n1;                                           \
+        typeof(o2) __o2 = o2;                                           \
+        typeof(o2) __n2 = n2;                                           \
+        typeof(o2) __dummy = n2;                                        \
+        asm volatile("cmpxchg8b "__percpu_arg(1)"\n\tsetz %0\n\t"       \
+                    : "=a"(__ret), "=m" (pcp1), "=d"(__dummy)           \
+                    :  "b"(__n1), "c"(__n2), "a"(__o1), "d"(__o2));     \
+        __ret;                                                          \
+})
+
+#define __this_cpu_cmpxchg_double_4(pcp1, pcp2, o1, o2, n1, n2)         percpu_cmpxchg8b_double(pcp1, o1, o2, n1, n2)
+#define this_cpu_cmpxchg_double_4(pcp1, pcp2, o1, o2, n1, n2)           percpu_cmpxchg8b_double(pcp1, o1, o2, n1, n2)
+#define irqsafe_cpu_cmpxchg_double_4(pcp1, pcp2, o1, o2, n1, n2)        percpu_cmpxchg8b_double(pcp1, o1, o2, n1, n2)
+#endif /* CONFIG_X86_CMPXCHG64 */
+
 /*
  * Per cpu atomic 64 bit operations are only available under 64 bit.
  * 32 bit must fall back to generic operations.
@@ -480,6 +500,34 @@ do {									\
 #define irqsafe_cpu_xor_8(pcp, val)     percpu_to_op("xor", (pcp), val)
 #define irqsafe_cpu_xchg_8(pcp, nval)   percpu_xchg_op(pcp, nval)
 #define irqsafe_cpu_cmpxchg_8(pcp, oval, nval)  percpu_cmpxchg_op(pcp, oval, nval)
+
+/*
+ * Pretty complex macro to generate cmpxchg16 instruction.  The instruction
+ * is not supported on early AMD64 processors so we must be able to emulate
+ * it in software.  The address used in the cmpxchg16 instruction must be
+ * aligned to a 16 byte boundary.
+ */
+#define percpu_cmpxchg16b_double(pcp1, o1, o2, n1, n2)                  \
+({                                                                      \
+        char __ret;                                                     \
+        typeof(o1) __o1 = o1;                                           \
+        typeof(o1) __n1 = n1;                                           \
+        typeof(o2) __o2 = o2;                                           \
+        typeof(o2) __n2 = n2;                                           \
+        typeof(o2) __dummy;                                             \
+        alternative_io("call this_cpu_cmpxchg16b_emu\n\t" P6_NOP4,      \
+                       "cmpxchg16b %%gs:(%%rsi)\n\tsetz %0\n\t",        \
+                       X86_FEATURE_CX16,                                \
+                       ASM_OUTPUT2("=a"(__ret), "=d"(__dummy)),         \
+                       "S" (&pcp1), "b"(__n1), "c"(__n2),               \
+                       "a"(__o1), "d"(__o2));                           \
+        __ret;                                                          \
+})
+
+#define __this_cpu_cmpxchg_double_8(pcp1, pcp2, o1, o2, n1, n2)         percpu_cmpxchg16b_double(pcp1, o1, o2, n1, n2)
+#define this_cpu_cmpxchg_double_8(pcp1, pcp2, o1, o2, n1, n2)           percpu_cmpxchg16b_double(pcp1, o1, o2, n1, n2)
+#define irqsafe_cpu_cmpxchg_double_8(pcp1, pcp2, o1, o2, n1, n2)        percpu_cmpxchg16b_double(pcp1, o1, o2, n1, n2)
+
 #endif
 
 /* This is not atomic against other CPUs -- CPU preemption needs to be off */