kernel: add support for getting percpu variables that belong to other CPUs

include/socks/percpu.h

@@ -15,13 +15,19 @@ extern "C" {
 #define percpu_get(var) \
 	__extension__({ \
 	preempt_disable(); \
-	__percpu_get(var); \
+	__percpu_get(this_cpu(), var); \
+	})
+
+#define percpu_get_from(cpu, var) \
+	__extension__({ \
+	preempt_disable(); \
+	__percpu_get(cpu, var); \
 	})
 
 #define percpu_put(var) preempt_enable();
 
 extern kern_status_t init_per_cpu_areas(void);
-extern void *__percpu_get(void *var);
+extern void *__percpu_get(unsigned int cpu, void *var);
 
 #ifdef __cplusplus
 }