physical memory userspace/kernel split on Linux x86-64

[Le Tan]

Hi,

2015-05-27 21:54 GMT+08:00 Karaoui mohamed lamine <moharaka at gmail.com>:
> 2015-05-27 3:12 GMT+02:00 Le Tan <tamlokveer at gmail.com>:
>>
>> Hi,
>> Is there an explict split between userspace and kernel in physical
>> memory on Linux x86-64? That is, given a physical address, can I tell
>> whether this address is from userspace or not?
>
>
> No. The same physical address can be  used by both the kernel and the
> userspace.
> The kernel and userspace share the same physical memory.
> Any memory page can be allocated for the userspace then released (free) then
> re-allocated for kernel use.

Got it. Thanks very much!

>> As far as I know, in virtual address space, the kernel will use the
>> upper half and the userspace will use the lower half. But what about
>> in physical address space?
>>
>>
>> Thanks very much!
>>
>> Le
>>
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>
>