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

[Ard Biesheuvel <ard.biesheuvel@arm.com>]

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@vmware.com>
>>> Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
>>> Cc: Peter Zijlstra <peterz@infradead.org>
>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>> Cc: Will Deacon <will.deacon@arm.com>
>>> Cc: Masami Hiramatsu <mhiramat@kernel.org>
>>> Cc: James Morse <james.morse@arm.com>
>>>
>>> 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@kernel.org>
> 
> 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?


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