Re: copy_*_user

[Xin Tong]

I do not remember, probably I was under the impression that kernel
accesses physical memory directly from my os course in college. So ,
the kernel access memory using the page table of the current process
here?

Thanks

Xin


On Sun, Oct 23, 2011 at 6:15 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 10/23/2011 11:23 AM, Xin Tong wrote:
>> I found that __copy_from_user_ll(void *to, const void __user *from,
>> unsigned long n) eventually calls some asm which use mov and rep on
>> the passed-in to & from pointers. This is in kernel mode and to & from
>> are virtual addresses ? are not the kernel accessing physical RAM
>> directly ( without pagetable ) ?
>
> No.  What gave you that idea?
>
>        -hpa
>
>
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