From: Catalin Marinas <catalin.marinas@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
Andrew Morton <akpm@linux-foundation.org>,
Marc Zyngier <maz@kernel.org>,
Oliver Upton <oliver.upton@linux.dev>,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Arnd Bergmann <arnd@arndb.de>, Oleg Nesterov <oleg@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
Kees Cook <keescook@chromium.org>, Shuah Khan <shuah@kernel.org>,
"Rick P. Edgecombe" <rick.p.edgecombe@intel.com>,
Deepak Gupta <debug@rivosinc.com>,
Ard Biesheuvel <ardb@kernel.org>,
Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
"H.J. Lu" <hjl.tools@gmail.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org
Subject: Re: [PATCH v4 03/36] arm64/gcs: Document the ABI for Guarded Control Stacks
Date: Fri, 18 Aug 2023 18:29:54 +0100 [thread overview]
Message-ID: <ZN+qki9EaZ6f9XNi@arm.com> (raw)
In-Reply-To: <f4cec4b3-c386-4873-aa1d-90528e062f2a@sirena.org.uk>
On Wed, Aug 09, 2023 at 04:34:38PM +0100, Mark Brown wrote:
> On Wed, Aug 09, 2023 at 03:24:14PM +0100, Catalin Marinas wrote:
> > On Mon, Aug 07, 2023 at 11:00:08PM +0100, Mark Brown wrote:
> > > +* When set PR_SHADOW_STACK_ENABLE flag allocates a Guarded Control Stack for
> >
> > The 'for' at the end of the line above is not needed.
> >
> > > + and enables GCS for the thread, enabling the functionality controlled by
>
> I find it a little clearer that it's a per thread stack here but sure.
If it reads better for you, feel free to keep it as is.
> > > +3. Allocation of Guarded Control Stacks
> > > +----------------------------------------
>
> > > +* When GCS is enabled for a thread a new Guarded Control Stack will be
> > > + allocated for it of size RLIMIT_STACK / 2 or 2 gigabytes, whichever is
> > > + smaller.
>
> > Is this number based on the fact that a function call would only push
> > the LR to GCS while standard function prologue pushes at least two
> > registers?
>
> It's actually based on bitrot that I'd initially chosen a smaller value
> since it's likely that functions will push at least something as you
> suggest, the patches now just use RLIMIT_STACK. I'll fix.
A related question - it may have been discussed intensively on the x86
thread (I may read it sometime) - why not have the libc map the shadow
stack and pass the pointer/size to clone3()? It saves us from having to
guess what the right size we'd need. struct clone_args is extensible.
(I plan to get back next week to this series, I'll need to read a bit
more on the spec)
--
Catalin
next prev parent reply other threads:[~2023-08-18 17:31 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-07 22:00 [PATCH v4 00/36] arm64/gcs: Provide support for GCS in userspace Mark Brown
2023-08-07 22:00 ` [PATCH v4 01/36] prctl: arch-agnostic prctl for shadow stack Mark Brown
2023-08-07 22:00 ` [PATCH v4 02/36] arm64: Document boot requirements for Guarded Control Stacks Mark Brown
2023-08-07 22:00 ` [PATCH v4 03/36] arm64/gcs: Document the ABI " Mark Brown
2023-08-09 14:24 ` Catalin Marinas
2023-08-09 15:34 ` Mark Brown
2023-08-10 8:55 ` Szabolcs Nagy
2023-08-10 11:41 ` Mark Brown
2023-08-10 13:34 ` Szabolcs Nagy
2023-08-10 16:30 ` Mark Brown
2023-08-18 17:29 ` Catalin Marinas [this message]
2023-08-18 19:38 ` Mark Brown
2023-08-22 16:49 ` Catalin Marinas
2023-08-22 17:53 ` Mark Brown
2023-08-23 10:09 ` Szabolcs Nagy
2023-08-23 12:51 ` Mark Brown
2023-08-23 16:45 ` Catalin Marinas
2023-08-23 17:18 ` Mark Brown
2023-08-23 17:40 ` Szabolcs Nagy
2023-08-23 18:16 ` Mark Brown
2023-08-24 15:43 ` Catalin Marinas
2023-08-24 17:38 ` Mark Brown
2023-08-30 12:37 ` Szabolcs Nagy
2023-08-30 16:42 ` Mark Brown
2023-08-23 13:11 ` Catalin Marinas
2023-08-23 15:50 ` Mark Brown
2023-09-28 16:59 ` Szabolcs Nagy
2023-10-02 19:49 ` Mark Brown
2023-10-02 21:43 ` Edgecombe, Rick P
2023-10-03 13:38 ` Mark Brown
2023-10-03 8:45 ` Szabolcs Nagy
2023-10-03 14:26 ` Mark Brown
2023-10-05 17:23 ` Catalin Marinas
2023-10-06 12:17 ` Mark Brown
2023-10-06 12:29 ` Eric W. Biederman
2023-10-06 13:23 ` Mark Brown
2023-10-19 17:08 ` Mark Brown
2023-08-07 22:00 ` [PATCH v4 04/36] arm64/sysreg: Add new system registers for GCS Mark Brown
2023-08-07 22:00 ` [PATCH v4 05/36] arm64/sysreg: Add definitions for architected GCS caps Mark Brown
2023-08-07 22:00 ` [PATCH v4 06/36] arm64/gcs: Add manual encodings of GCS instructions Mark Brown
2023-08-07 22:00 ` [PATCH v4 07/36] arm64/gcs: Provide copy_to_user_gcs() Mark Brown
2023-08-11 16:36 ` Catalin Marinas
2023-08-16 18:26 ` Mark Brown
2023-08-07 22:00 ` [PATCH v4 08/36] arm64/cpufeature: Runtime detection of Guarded Control Stack (GCS) Mark Brown
2023-08-07 22:00 ` [PATCH v4 09/36] arm64/mm: Allocate PIE slots for EL0 guarded control stack Mark Brown
2023-08-11 14:23 ` Catalin Marinas
2023-08-15 23:21 ` Mark Brown
2023-08-07 22:00 ` [PATCH v4 10/36] mm: Define VM_SHADOW_STACK for arm64 when we support GCS Mark Brown
2023-08-07 22:00 ` [PATCH v4 11/36] arm64/mm: Map pages for guarded control stack Mark Brown
2023-08-10 17:20 ` Catalin Marinas
2023-08-07 22:00 ` [PATCH v4 12/36] KVM: arm64: Manage GCS registers for guests Mark Brown
2023-08-07 22:00 ` [PATCH v4 13/36] arm64/gcs: Allow GCS usage at EL0 and EL1 Mark Brown
2023-08-07 22:00 ` [PATCH v4 14/36] arm64/idreg: Add overrride for GCS Mark Brown
2023-08-07 22:00 ` [PATCH v4 15/36] arm64/hwcap: Add hwcap " Mark Brown
2023-08-07 22:00 ` [PATCH v4 16/36] arm64/traps: Handle GCS exceptions Mark Brown
2023-08-07 22:00 ` [PATCH v4 17/36] arm64/mm: Handle GCS data aborts Mark Brown
2023-08-11 15:09 ` Catalin Marinas
2023-08-15 23:54 ` Mark Brown
2023-08-07 22:00 ` [PATCH v4 18/36] arm64/gcs: Context switch GCS state for EL0 Mark Brown
2023-08-11 15:32 ` Catalin Marinas
2023-08-16 18:15 ` Mark Brown
2023-08-22 16:34 ` Catalin Marinas
2023-08-22 17:01 ` Mark Brown
2023-08-07 22:00 ` [PATCH v4 19/36] arm64/gcs: Allocate a new GCS for threads with GCS enabled Mark Brown
2023-08-11 16:26 ` Catalin Marinas
2023-08-18 20:15 ` Mark Brown
2023-08-07 22:00 ` [PATCH v4 20/36] arm64/gcs: Implement shadow stack prctl() interface Mark Brown
2023-08-07 22:00 ` [PATCH v4 21/36] arm64/mm: Implement map_shadow_stack() Mark Brown
2023-08-11 16:38 ` Catalin Marinas
2023-08-18 17:08 ` Mark Brown
2023-08-22 16:40 ` Catalin Marinas
2023-08-22 17:05 ` Mark Brown
2023-08-15 20:42 ` Edgecombe, Rick P
2023-08-15 21:01 ` Mark Brown
2023-08-07 22:00 ` [PATCH v4 22/36] arm64/signal: Set up and restore the GCS context for signal handlers Mark Brown
2023-08-07 22:00 ` [PATCH v4 23/36] arm64/signal: Expose GCS state in signal frames Mark Brown
2023-08-07 22:00 ` [PATCH v4 24/36] arm64/ptrace: Expose GCS via ptrace and core files Mark Brown
2023-08-07 22:00 ` [PATCH v4 25/36] arm64: Add Kconfig for Guarded Control Stack (GCS) Mark Brown
2023-08-07 22:00 ` [PATCH v4 26/36] kselftest/arm64: Verify the GCS hwcap Mark Brown
2023-08-07 22:00 ` [PATCH v4 27/36] kselftest/arm64: Add GCS as a detected feature in the signal tests Mark Brown
2023-08-07 22:00 ` [PATCH v4 28/36] kselftest/arm64: Add framework support for GCS to signal handling tests Mark Brown
2023-08-07 22:00 ` [PATCH v4 29/36] kselftest/arm64: Allow signals tests to specify an expected si_code Mark Brown
2023-08-07 22:00 ` [PATCH v4 30/36] kselftest/arm64: Always run signals tests with GCS enabled Mark Brown
2023-08-07 22:00 ` [PATCH v4 31/36] kselftest/arm64: Add very basic GCS test program Mark Brown
2023-08-07 22:00 ` [PATCH v4 32/36] kselftest/arm64: Add a GCS test program built with the system libc Mark Brown
2023-08-07 22:00 ` [PATCH v4 33/36] kselftest/arm64: Add test coverage for GCS mode locking Mark Brown
2023-08-07 22:00 ` [PATCH v4 34/36] selftests/arm64: Add GCS signal tests Mark Brown
2023-08-07 22:00 ` [PATCH v4 35/36] kselftest/arm64: Add a GCS stress test Mark Brown
2023-08-07 22:00 ` [PATCH v4 36/36] kselftest/arm64: Enable GCS for the FP stress tests Mark Brown
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