[PATCH] powerpc/vdso64: inline __get_datapage()

[Santosh Sivaraj]

Christophe Leroy <christophe.leroy at c-s.fr> writes:

> Le 21/08/2019 à 14:15, Segher Boessenkool a écrit :
>> On Wed, Aug 21, 2019 at 01:50:52PM +0200, Christophe Leroy wrote:
>>> Do you have any idea on how to avoid that bcl/mflr stuff ?
>> 
>> Do a load from some fixed address?  Maybe an absolute address, even?
>> lwz r3,-12344(0)  or similar (that address is in kernel space...)
>> 
>> There aren't many options, and certainly not many *good* options!
>> 
>
> IIUC, the VDSO is seen by apps the same way as a dynamic lib. Couldn't 
> the relocation be done only once when the app loads the VDSO as for a 
> regular .so lib ?

How does address space randomization work for .so libs?

>
> It looks like it is what others do, at least x86 and arm64, unless I 
> misunderstood their code.
>
> Christophe