Fix percpu patch breakage

include/linux/compiler.h

@@ -15,7 +15,6 @@
 
 /* This macro obfuscates arithmetic on a variable address so that gcc
    shouldn't recognize the original var, and make assumptions about it */
-	strcpy(s, "xxx"+X) => memcpy(s, "xxx"+X, 4-X) */
 #define RELOC_HIDE(var, off)					\
   ({ __typeof__(&(var)) __ptr;					\
     __asm__ ("" : "=g"(__ptr) : "0"((void *)&(var) + (off)));	\

init/main.c

@@ -287,6 +287,9 @@ static void __init setup_per_cpu_areas(void)
 
 	/* Copy section for each CPU (we discard the original) */
 	size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
+	if (!size)
+		return;
+
 	ptr = alloc_bootmem(size * NR_CPUS);
 
 	for (i = 0; i < NR_CPUS; i++, ptr += size) {