-#ifdef swp_is_buggy
- case 1:
- local_irq_save(flags);
- ret = *(volatile unsigned char *)ptr;
- *(volatile unsigned char *)ptr = x;
- local_irq_restore(flags);
- break;
-
- case 4:
- local_irq_save(flags);
- ret = *(volatile unsigned long *)ptr;
- *(volatile unsigned long *)ptr = x;
- local_irq_restore(flags);
- break;
+#if __LINUX_ARM_ARCH__ >= 6
+ case 1:
+ asm volatile("@ __xchg1\n"
+ "1: ldrexb %0, [%3]\n"
+ " strexb %1, %2, [%3]\n"
+ " teq %1, #0\n"
+ " bne 1b"
+ : "=&r" (ret), "=&r" (tmp)
+ : "r" (x), "r" (ptr)
+ : "memory", "cc");
+ break;
+ case 4:
+ asm volatile("@ __xchg4\n"
+ "1: ldrex %0, [%3]\n"
+ " strex %1, %2, [%3]\n"
+ " teq %1, #0\n"
+ " bne 1b"
+ : "=&r" (ret), "=&r" (tmp)
+ : "r" (x), "r" (ptr)
+ : "memory", "cc");
+ break;
+#elif defined(swp_is_buggy)
+#ifdef CONFIG_SMP
+#error SMP is not supported on this platform
+#endif
+ case 1:
+ local_irq_save(flags);
+ ret = *(volatile unsigned char *)ptr;
+ *(volatile unsigned char *)ptr = x;
+ local_irq_restore(flags);
+ break;
+
+ case 4:
+ local_irq_save(flags);
+ ret = *(volatile unsigned long *)ptr;
+ *(volatile unsigned long *)ptr = x;
+ local_irq_restore(flags);
+ break;