__va（）和phys_to_virt（）有什么区别？

phys_to_virt和__va是预处理器宏。 phys_to_virt：

#if !defined(CONFIG_MMU) #define virt_to_phys(address) ((unsigned long)(address)) #define phys_to_virt(address) ((void *)(address)) #else #define virt_to_phys(address) (__pa(address)) #define phys_to_virt(address) (__va(address)) #endif 

和__va

 #define __va(x) ((void *)((unsigned long) (x))) 

如果CONFIG_MMU没有被定义，则等于。