什么是Linux的__user宏的含义是什么？ [英] What are the implications of the linux __user macro?

问题描述

我希望有人可以解释在Linux内核源代码中使用的__user宏的细微差别。

I was hoping someone could explain the nuances of the __user macro used in the linux kernel source.

首先，宏观：

# define __user         __attribute__((noderef, address_space(1)))

现在，一些谷歌搜索后，我读了这个宏允许一个指定的指针为属于用户地址空间，而且它不应该被取消引用。

Now, after some googling I read that this macro allows one to designate a pointer as belonging to the user address space, and that it should not be dereferenced.

我可能会丢失一些明显的事实，但也有人请解释这样一个宏的含义是什么？比如，什么是在哪里这个宏将使用一个很好的例子？再次，原谅我，如果我失去了一些东西明显。

I may be missing some obvious facts, but could someone please explain the implications of such a macro? For instance, what is a good example of where this macro would be of use? Again, forgive me if I am missing something obvious.

为了把这个在某些情况下，我来到翻过宏在检查一些USB code（Linux的/ usbdevice_fs.h）。我只是寻找这个宏的一般理解（或者其他类似的）在内核中使用。

To put this in some context, I came accross the macro while examining some USB code (linux/usbdevice_fs.h). I am only looking for a general understanding of this macros( or others like it) use within the kernel.

感谢您看！

推荐答案

这让像稀疏工具来告诉内核开发他们正在可能使用不受信任的指针（或可能是在当前的虚拟地址映射无效指针）不正确。

It allows tools like sparse to tell kernel developers that they're possibly using an untrusted pointer (or a pointer that may be invalid in the current virtual address mapping) improperly.

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