Re: [PATCH 2/7] x86/enter: MACROS to set/clear IBRS

Andy Lutomirski
2018-01-05T04:54:36Z

On Thu, Jan 4, 2018 at 2:23 PM, Dave Hansen <dave.hansen@intel.com> wrote:
> On 01/04/2018 02:21 PM, Tim Chen wrote:
>>> Does this really have to live outside of arch/x86/entry/ ?
>>>
>> There are some inline C routines later in this file
>> that will be needed by other functions. Want to consolidate
>> them in the same file.
>
> We could put all of the assembly into calling.h along with the PTI
> assembly. Seems as sane a place as anywhere else to put it.
>

We should also stop thinking that NMI is at all special. All the
paranoid entry paths + NMI should just save and restore it, just like
CR3. Otherwise we get nasty corner cases with MCE, kprobes, etc.