Confuse about RHIUpdateUniformBuffer

I am learning about the UE4 Rendering,I found a piece of code I cannot understand,I will very appreciate if someone can help me.

Q: There is a structure “FOpaqueBasePassUniformParameters” contains some data,some of them are the pointer data,just like “FRHIResource DBufferTextureA*”.
That’s OK,but later in the “UpdateUniformBufferImmediate” code,there is a function named “UpdateUniformBufferContents”,they copy all the the data in this structure into a GPU Mapped Resource include the pointer data,I cannot understand,the pointer data should store the cpu address,it shouldn’t be used in GPU,I don’t know if I missunder something.