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From: Andrew Morton <akpm@linux-foundation.org>
To: Deepak Gupta <debug@rivosinc.com>
Cc: rick.p.edgecombe@intel.com, broonie@kernel.org,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] mm: abstract shadow stack vma behind arch_is_shadow_stack_vma
Date: Wed, 27 Dec 2023 14:24:41 -0800	[thread overview]
Message-ID: <20231227142441.f9a76fa3c8b9b79eea8f93a2@linux-foundation.org> (raw)
In-Reply-To: <CAKC1njTry42zAkZWq3pAgoe3YFaHN6UcB4i56BDQRxYbTEigRw@mail.gmail.com>

On Wed, 27 Dec 2023 14:20:36 -0800 Deepak Gupta <debug@rivosinc.com> wrote:

> On Wed, Dec 27, 2023 at 1:45 PM Andrew Morton <akpm@linux-foundation.org> wrote:
> >
> > On Fri, 22 Dec 2023 15:51:04 -0800 Deepak Gupta <debug@rivosinc.com> wrote:
> >
> > > x86 has used VM_SHADOW_STACK (alias to VM_HIGH_ARCH_5) to encode shadow
> > > stack VMA. VM_SHADOW_STACK is thus not possible on 32bit. Some arches may
> > > need a way to encode shadow stack on 32bit and 64bit both and they may
> > > encode this information differently in VMAs.
> >
> > Is such a patch in the pipeline?  Otherwise we're making a change that
> > serves no purpose.
> 
> Yes I do have patches in the pipeline for riscv.
> On riscv, presence of only `VM_WRITE` (i.e. (flags & (VM_READ |
> VM_WRITE | VM_EXEC))
> == VM_WRITE) would mean a shadow stack.
> And yes there would be  relevant patches to ensure that existing consumers using
> `PROT_WRITE` gets translated to (VM_WRITE | VM_READ)

OK, please plan to carry this patch in whatever tree contains the above.




  reply	other threads:[~2023-12-27 22:24 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-22 23:51 Deepak Gupta
2023-12-27 21:45 ` Andrew Morton
2023-12-27 22:20   ` Deepak Gupta
2023-12-27 22:24     ` Andrew Morton [this message]
2023-12-30  2:30       ` Deepak Gupta
2024-01-02 13:56   ` Mike Rapoport
2024-01-02 18:45     ` Deepak Gupta
2024-01-02 17:50 ` Edgecombe, Rick P
2024-01-02 18:45   ` Deepak Gupta

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