From: Ard Biesheuvel <ardb@kernel.org>
To: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
Cc: Mark Brown <broonie@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Mark Rutland <mark.rutland@arm.com>,
Michal Marek <michal.lkml@markovi.net>,
Julien Thierry <jthierry@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-efi <linux-efi@vger.kernel.org>,
linux-hardening@vger.kernel.org, live-patching@vger.kernel.org,
Will Deacon <will@kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Kees Cook <keescook@chromium.org>
Subject: Re: [RFC PATCH 00/17] objtool: add base support for arm64
Date: Fri, 22 Jan 2021 22:43:09 +0100 [thread overview]
Message-ID: <CAMj1kXFr0wvx-hG6nBY4ibju9ww4x0CGhQber3MZQ2ZZn9LHWw@mail.gmail.com> (raw)
In-Reply-To: <bebccb15-1195-c004-923e-74d8444250e1@linux.microsoft.com>
On Fri, 22 Jan 2021 at 22:15, Madhavan T. Venkataraman
<madvenka@linux.microsoft.com> wrote:
>
>
>
> On 1/22/21 11:43 AM, Mark Brown wrote:
> > On Thu, Jan 21, 2021 at 12:54:52PM -0600, Josh Poimboeuf wrote:
> >
> >> 2) The shadow stack idea sounds promising -- how hard would it be to
> >> make a prototype reliable unwinder?
> >
> > In theory it doesn't look too hard and I can't see a particular reason
> > not to try doing this - there's going to be edge cases but hopefully for
> > reliable stack trace they're all in areas where we would be happy to
> > just decide the stack isn't reliable anyway, things like nesting which
> > allocates separate shadow stacks for each nested level for example.
> > I'll take a look.
> >
>
> I am a new comer to this discussion and I am learning. Just have some
> questions. Pardon me if they are obvious or if they have already been
> asked and answered.
>
> Doesn't Clang already have support for a shadow stack implementation for ARM64?
> We could take a look at how Clang does it.
>
> Will there not be a significant performance hit? May be, some of it can be
> mitigated by using a parallel shadow stack rather than a compact one.
>
> Are there any longjmp style situations in the kernel where the stack is
> unwound by several frames? In these cases, the shadow stack must be unwound
> accordingly.
>
Hello Madhavan,
Let's discuss the details of shadow call stacks on a separate thread,
instead of further hijacking Julien's series.
next prev parent reply other threads:[~2021-01-22 21:44 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210120173800.1660730-1-jthierry@redhat.com>
[not found] ` <CAMj1kXHO0wgcZ4ZDxj1vS9s7Szfpz8Nz=SAW_=Dnnjy+S9AtyQ@mail.gmail.com>
[not found] ` <186bb660-6e70-6bbf-4e96-1894799c79ce@redhat.com>
[not found] ` <CAMj1kXHznGnN2UEai1c2UgyKuTFCS5SZ+qGR6VJwyCuccViw_A@mail.gmail.com>
[not found] ` <YAlkOFwkb6/hFm1Q@hirez.programming.kicks-ass.net>
[not found] ` <CAMj1kXE+675mbS66kteKHNfcrco84WTaEL6ncVkkV7tQgbMpFw@mail.gmail.com>
2021-01-21 18:54 ` [RFC PATCH 00/17] objtool: add base support for arm64 Josh Poimboeuf
2021-01-22 17:43 ` Mark Brown
2021-01-22 17:54 ` Ard Biesheuvel
2021-01-28 22:10 ` Madhavan T. Venkataraman
2021-01-22 21:15 ` Madhavan T. Venkataraman
2021-01-22 21:43 ` Ard Biesheuvel [this message]
2021-01-22 21:44 ` Madhavan T. Venkataraman
2021-01-25 21:19 ` Josh Poimboeuf
2021-01-22 21:16 ` Madhavan T. Venkataraman
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