Re: [GIT PULL] x86/iopl changes for v5.5

From: Ingo Molnar
Date: Mon Nov 25 2019 - 14:25:03 EST



* Ingo Molnar <mingo@xxxxxxxxxx> wrote:

> Linus,
>
> Please pull the latest x86-iopl-for-linus git tree from:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-iopl-for-linus
>
> # HEAD: e3cb0c7102f04c83bf1a7cb1d052e92749310b46 x86/ioperm: Fix use of deprecated config option
>
> This tree implements a nice simplification of the iopl and ioperm code
> that Thomas Gleixner discovered: we can implement the IO privilege
> features of the iopl system call by using the IO permission bitmap in
> permissive mode, while trapping CLI/STI/POPF/PUSHF uses in user-space if
> they change the interrupt flag.
>
> This tree implements that feature, with testing facilities and related
> cleanups.

Forgot to list the conflicts that may arise if you merge this after the
other x86 bits.

Firstly the symbol bits would conflict here:

arch/x86/entry/entry_32.S
arch/x86/kernel/head_32.S
arch/x86/xen/xen-asm_32.S

I've resolved them in tip:WIP.x86/asm if you want to double check:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git WIP.x86/asm

but usually you do the resolutions better. :-)

There's also a conflict in arch/x86/include/asm/pgtable_32_types.h.

But there's also a semantic conflict that would trigger if you pull this
after the x86/urgent bits, interacting with:

05b042a19443: ("x86/pti/32: Calculate the various PTI cpu_entry_area sizes correctly, make the CPU_ENTRY_AREA_PAGES assert precise")

After that commit the CPU_ENTRY_AREA_PAGES value has to be precise, and
edited to 41 in the merge commit if I did everything write with the pull
requests.

This too is resolved in tip:WIP.x86/asm, in the following merge commits:

22d7b9359a9a: ("Merge branch 'x86/iopl' into x86/asm, to resolve conflicts")
7543765dd362: ("Merge branch 'x86/urgent' into x86/iopl, to resolve conflicts")

Thanks,

Ingo