1 files changed, 14 insertions, 0 deletions

diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index cd28f9ad910d..f899e01a8ac9 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -47,6 +47,20 @@
 #ifdef CONFIG_SMP
 #define __percpu_arg(x)         "%%"__stringify(__percpu_seg)":%P" #x
 #define __my_cpu_offset         percpu_read(this_cpu_off)
+
+/*
+ * Compared to the generic __my_cpu_offset version, the following
+ * saves one instruction and avoids clobbering a temp register.
+ */
+#define __this_cpu_ptr(ptr)                             \
+({                                                      \
+        unsigned long tcp_ptr__;                        \
+        __verify_pcpu_ptr(ptr);                         \
+        asm volatile("add " __percpu_arg(1) ", %0"      \
+                     : "=r" (tcp_ptr__)                 \
+                     : "m" (this_cpu_off), "0" (ptr));  \
+        (typeof(*(ptr)) __kernel __force *)tcp_ptr__;   \
+})
 #else
 #define __percpu_arg(x)         "%P" #x
 #endif