Re: [PATCH 0/4] arm64: wire up VM_FLUSH_RESET_PERMS

[Ard Biesheuvel]

(+ Catalin)

On Mon, 24 Jun 2019 at 13:23, Ard Biesheuvel <ard.biesheuvel@xxxxxxx> wrote:
>
> On 6/24/19 1:16 PM, Will Deacon wrote:
> > On Tue, May 28, 2019 at 11:04:20AM +0100, Will Deacon wrote:
> >> On Thu, May 23, 2019 at 11:22:52AM +0100, Ard Biesheuvel wrote:
> >>> Wire up the code introduced in v5.2 to manage the permissions
> >>> of executable vmalloc regions (and their linear aliases) more
> >>> strictly.
> >>>
> >>> One of the things that came up in the internal discussion is
> >>> whether non-x86 architectures have any benefit at all from the
> >>> lazy vunmap feature, and whether it would perhaps be better to
> >>> implement eager vunmap instead.
> >>>
> >>> Cc: Nadav Amit <namit@xxxxxxxxxx>
> >>> Cc: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
> >>> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> >>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> >>> Cc: Will Deacon <will.deacon@xxxxxxx>
> >>> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> >>> Cc: James Morse <james.morse@xxxxxxx>
> >>>
> >>> Ard Biesheuvel (4):
> >>>    arm64: module: create module allocations without exec permissions
> >>>    arm64/mm: wire up CONFIG_ARCH_HAS_SET_DIRECT_MAP
> >>>    arm64/kprobes: set VM_FLUSH_RESET_PERMS on kprobe instruction pages
> >>>    arm64: bpf: do not allocate executable memory
> >>>
> >>>   arch/arm64/Kconfig                  |  1 +
> >>>   arch/arm64/include/asm/cacheflush.h |  3 ++
> >>>   arch/arm64/kernel/module.c          |  4 +-
> >>>   arch/arm64/kernel/probes/kprobes.c  |  4 +-
> >>>   arch/arm64/mm/pageattr.c            | 48 ++++++++++++++++----
> >>>   arch/arm64/net/bpf_jit_comp.c       |  2 +-
> >>>   mm/vmalloc.c                        | 11 -----
> >>>   7 files changed, 50 insertions(+), 23 deletions(-)
> >>
> >> Thanks, this all looks good to me. I can get pick this up for 5.2 if
> >> Rick's fixes [1] land soon enough.
> >
> > Bah, I missed these landing in -rc5 and I think it's a bit too late for
> > us to take this for 5.2. now particularly with our limited ability to
> > fix any late regressions that might arise.
> >
> > In which case, Catalin, please can you take these for 5.3? You might run
> > into some testing failures with for-next/core due to the late of Rick's
> > fixes, but linux-next should be alright and I don't think you'll get any
> > conflicts.
> >
> > Acked-by: Will Deacon <will@xxxxxxxxxx>
> >
> > Ard: are you ok with that?
> >
>
> That is fine, although I won't be around to pick up the pieces by the
> time the merge window opens. Also, I'd like to follow up on the lazy
> vunmap thing for non-x86, but perhaps we can talk about this at plumbers?
>

Actually, you will run into a couple of conflicts. Let me know if you
want me to respin (although they still won't apply cleanly to both
for-next/core and -next)