Re: [PATCH 0/7] Misc GDT fixes and a cleanup

From: Ingo Molnar
Date: Thu Mar 23 2017 - 03:31:58 EST



* Andy Lutomirski <luto@xxxxxxxxxx> wrote:

> Hi all-
>
> This applies to tip:x86/mm. For ease of testing, the series is here, too:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/tag/?h=review_20170322_gdt_and_wp
>
> This fixes a few issues, most of which appear to be rather old. For
> whatever reason, Thomas' GDT series unearthed them. (And one is a
> genuine bug in Thomas' code but, in his defense, he might have
> cut-and-pasted it verbatim from the identical bug in the EFI code.)
>
> The last three patches are cleanups I did while tracking these down.
>
> Boris, any chance you could test this series on Xen? The 64-bit
> case works for me, but I'm having issues testing on 32-bit right
> now.
>
> Ingo, the first patch should address your concerns from the earlier
> version.
>
> Andy Lutomirski (7):
> selftests/x86/ldt_gdt_32: Work around a glibc sigaction bug
> x86/gdt: Fix setup_fixmap_gdt() to use the correct PA
> x86/efi/32: Fix EFI on systems where the percpu GDT is virtually
> mapped
> x86/boot/32: Defer resyncing initial_page_table until percpu is set up
> x86/gdt: Get rid of the get_*_gdt_*_vaddr() helpers
> x86/xen/gdt: Use X86_FEATURE_XENPV instead of globals for the GDT
> fixup
> x86/boot/32: Rewrite test_wp_bit()

Ok, looks mostly good to me and I've applied the first 6 patches to tip:x86/mm and
will push them out if everything tests out fine.

Regarding patch #7: could you please split the last patch into two, and rebase the
wp_works_ok removal on the very latest tip:x86/mm tree? There's some pending
changes in tip:x86/process that conflict badly, so I've merged it into tip:x86/mm
for a conflict-free base. That patch is better split in two anyway, as it does two
only marginally related things.

Thanks,

Ingo