Re: [GIT PULL] x86 fixes

Thomas Gleixner
2017-12-17T11:41:47Z

On Sat, 16 Dec 2017, Andy Lutomirski wrote:
> On Fri, Dec 15, 2017 at 8:07 AM, Ingo Molnar <mingo@kernel.org> wrote:
> I few things I noticed in the PTI tree:
>
> "x86/mm/pti: Map ESPFIX into user space" has a leftover pr_err().
> Sorry, my bad, I've spent *way* too long looking at this crap to
> retain my sanity. Also, if you're feeling like being super tidy, the
> init/main.c change in their could be folded in to whatever patch adds
> pti_init() in the first place, but it doesn't really matter.

I split it out into a separate patch and got rid of all the ifdef mess
while at it.

> "x86/pti: Map the vsyscall page if needed" has a change to
> pgtable_64.h that could be folded into an earlier patch. This is
> probably my fault for applying Dave Hansen's cleanup request to the
> wrong patch.

Done

> "x86/mm/64: Make a full PGD-entry size hole in the memory map" would
> benefit from a mention of "5-level" somewhere in the subject or
> changelog.

Will do

> In "x86/fixmap: Add debugstore entries to cpu_entry_area", I think the
> function "set_percpu_fixmap_ptes" is misnamed. It should be something
> like "allocate_percpu_fixmap_ptes", perhaps,

Ok.

> and it should either warn
> or do nothing if the PTE is already present, I think. As it stands,
> it's a wee bit dangerous.

Well, it's not more dangerous than all the other fixmap stuff we are
doing. The only difference is that it does not install a mapping, it just
makes sure that the PTE page is populated.

> X86_BUG_CPU_SECURE_MODE_PTI should be added to DISABLED_FEATURES or
> DISABLED_BUGS or whatever if it's not configured in, which will reduce
> bloat. Borislav, that's kind of up your alley, since I don't think
> the appropriate mask even exists right now.

Will have a look.

Thanks,

tglx