Re: [PATCH] x86/xen: Delay get_cpu_cap until stack canary is established

From: Juergen Gross
Date: Tue Mar 20 2018 - 02:28:16 EST


On 19/03/18 23:22, Boris Ostrovsky wrote:
> On 03/19/2018 12:58 PM, Jason Andryuk wrote:
>> Commit 2cc42bac1c79 ("x86-64/Xen: eliminate W+X mappings") introduced a
>> call to get_cpu_cap, which is fstack-protected. This is works on x86-64
>
> s/This is works/This works/
>
> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
>
> Do we still need 4f277295e54?

I'd rather keep it in order to avoid nasty problems in case something
changes. After all we are trying to do an initialization in C code
which should be done in assembly before entering the C part. Doing this
properly for 32-bit pv-kernels would be rather difficult, but this is no
reason to drop the correct solution for the 64-bit case.


Juergen