Hi Huacai,
On Thu, Sep 27, 2018 at 02:26:42PM +0800, 陈华才 wrote:
> I think this patch can solve my problem, but I have something to say:
>
> 1, VDSO randomization is introduced in commit
> ccd3988086364837d0c0fb4563d7 in 3.19. So this patch should backported
> as early as 3.19.
Ugh, OK so the not-really-a-VDSO page that we called VDSO before we
really had a VDSO was randomly located too. A backport to that would
need to be significantly different.
However the only currently supported LTS kernel older than 4.4 (which
introduced the real VDSO) is 3.16. 3.16 didn't support the randomization
anyway, I don't think it's worth the effort to backport any further than
4.4.
> 2, vdso_base() may need to be modified for 4.4, because 4.4 has no
> delay slot emulation.
Yes I know. The GIC code changed in 4.14 too so backports will need to
take that into account too.
> 3, Maybe it is better to set VDSO_RANDOMIZE_SIZE to 16MB for 64bit
> kernel, because commit ccd3988086364837d0c0fb4563d7 use 16MB.
It actually uses 256MB for MIPS64. Since address space isn't scarce
for MIPS64 I'll go with that.
Thanks,
Paul
