From: Mark Brown <broonie@kernel.org>
To: Deepak Gupta <debug@rivosinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
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>,
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>,
Florian Weimer <fweimer@redhat.com>,
Christian Brauner <brauner@kernel.org>,
Thiago Jung Bauermann <thiago.bauermann@linaro.org>,
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 v7 20/39] arm64/gcs: Context switch GCS state for EL0
Date: Wed, 13 Dec 2023 20:02:24 +0000 [thread overview]
Message-ID: <b2a717a7-e6d3-4fa9-921e-156c17ad5424@sirena.org.uk> (raw)
In-Reply-To: <CAKC1njQVB71A8fQBLmBnx++agM12XDLhS=7iL7-A4NTXSqUM+A@mail.gmail.com>
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On Wed, Dec 13, 2023 at 11:59:45AM -0800, Deepak Gupta wrote:
> On Wed, Nov 22, 2023 at 1:45 AM Mark Brown <broonie@kernel.org> wrote:
> > + if (task->thread.gcs_el0_mode & PR_SHADOW_STACK_ENABLE)
> > + gcscre0_el1 |= GCSCRE0_EL1_RVCHKEN | GCSCRE0_EL1_PCRSEL;
> If the intent is to disable, is the GCS stack freed or kept around?
> I expect if libc is taking the decision to disable, kernel should free it up.
> Is it freed in some other flow?
Kept around and freed on thread exit. There is a potential race between
for example disabling in a signal handler and something trying to walk
the stack so we err on the side of caution.
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next prev parent reply other threads:[~2023-12-13 20:02 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-22 9:42 [PATCH v7 00/39] arm64/gcs: Provide support for GCS in userspace Mark Brown
2023-11-22 9:42 ` [PATCH v7 01/39] arm64/mm: Restructure arch_validate_flags() for extensibility Mark Brown
2023-11-22 9:42 ` [PATCH v7 02/39] prctl: arch-agnostic prctl for shadow stack Mark Brown
2023-12-12 19:17 ` Deepak Gupta
2023-12-12 19:22 ` Mark Brown
2023-12-13 0:50 ` Deepak Gupta
2023-12-13 13:37 ` Mark Brown
2023-12-13 19:43 ` Deepak Gupta
2023-12-13 19:48 ` Mark Brown
2023-12-12 20:17 ` Edgecombe, Rick P
2023-12-12 20:26 ` Mark Brown
2023-12-12 21:22 ` Edgecombe, Rick P
2023-12-13 13:49 ` Mark Brown
2023-11-22 9:42 ` [PATCH v7 03/39] mman: Add map_shadow_stack() flags Mark Brown
2023-11-22 9:42 ` [PATCH v7 04/39] arm64: Document boot requirements for Guarded Control Stacks Mark Brown
2023-11-22 9:42 ` [PATCH v7 05/39] arm64/gcs: Document the ABI " Mark Brown
2023-11-22 9:42 ` [PATCH v7 06/39] arm64/sysreg: Add new system registers for GCS Mark Brown
2023-11-22 9:42 ` [PATCH v7 07/39] arm64/sysreg: Add definitions for architected GCS caps Mark Brown
2023-11-22 9:42 ` [PATCH v7 08/39] arm64/gcs: Add manual encodings of GCS instructions Mark Brown
2023-11-22 9:42 ` [PATCH v7 09/39] arm64/gcs: Provide put_user_gcs() Mark Brown
2023-11-22 9:42 ` [PATCH v7 10/39] arm64/cpufeature: Runtime detection of Guarded Control Stack (GCS) Mark Brown
2023-11-22 9:42 ` [PATCH v7 11/39] arm64/mm: Allocate PIE slots for EL0 guarded control stack Mark Brown
2023-11-22 9:42 ` [PATCH v7 12/39] mm: Define VM_SHADOW_STACK for arm64 when we support GCS Mark Brown
2023-11-22 9:42 ` [PATCH v7 13/39] arm64/mm: Map pages for guarded control stack Mark Brown
2023-12-04 3:01 ` Thiago Jung Bauermann
2023-11-22 9:42 ` [PATCH v7 14/39] KVM: arm64: Manage GCS registers for guests Mark Brown
2023-11-22 9:42 ` [PATCH v7 15/39] arm64/gcs: Allow GCS usage at EL0 and EL1 Mark Brown
2023-11-22 9:42 ` [PATCH v7 16/39] arm64/idreg: Add overrride for GCS Mark Brown
2023-11-22 9:42 ` [PATCH v7 17/39] arm64/hwcap: Add hwcap " Mark Brown
2023-11-22 9:42 ` [PATCH v7 18/39] arm64/traps: Handle GCS exceptions Mark Brown
2023-11-22 9:42 ` [PATCH v7 19/39] arm64/mm: Handle GCS data aborts Mark Brown
2023-11-22 9:42 ` [PATCH v7 20/39] arm64/gcs: Context switch GCS state for EL0 Mark Brown
2023-12-13 19:59 ` Deepak Gupta
2023-12-13 20:02 ` Mark Brown [this message]
2023-11-22 9:42 ` [PATCH v7 21/39] arm64/gcs: Allocate a new GCS for threads with GCS enabled Mark Brown
2023-12-06 20:22 ` Thiago Jung Bauermann
2023-11-22 9:42 ` [PATCH v7 22/39] arm64/gcs: Implement shadow stack prctl() interface Mark Brown
2023-12-06 21:27 ` Thiago Jung Bauermann
2023-11-22 9:42 ` [PATCH v7 23/39] arm64/mm: Implement map_shadow_stack() Mark Brown
2023-12-06 21:44 ` Thiago Jung Bauermann
2023-11-22 9:42 ` [PATCH v7 24/39] arm64/signal: Set up and restore the GCS context for signal handlers Mark Brown
2023-12-09 3:15 ` Thiago Jung Bauermann
2023-12-09 13:09 ` Mark Brown
2023-11-22 9:42 ` [PATCH v7 25/39] arm64/signal: Expose GCS state in signal frames Mark Brown
2023-12-09 22:28 ` Thiago Jung Bauermann
2023-11-22 9:42 ` [PATCH v7 26/39] arm64/ptrace: Expose GCS via ptrace and core files Mark Brown
2023-12-09 23:49 ` Thiago Jung Bauermann
2023-12-10 14:22 ` Mark Brown
2023-11-22 9:42 ` [PATCH v7 27/39] arm64: Add Kconfig for Guarded Control Stack (GCS) Mark Brown
2023-11-22 9:42 ` [PATCH v7 28/39] kselftest/arm64: Verify the GCS hwcap Mark Brown
2023-11-22 9:42 ` [PATCH v7 29/39] kselftest/arm64: Add GCS as a detected feature in the signal tests Mark Brown
2023-11-22 9:42 ` [PATCH v7 30/39] kselftest/arm64: Add framework support for GCS to signal handling tests Mark Brown
2023-11-22 9:42 ` [PATCH v7 31/39] kselftest/arm64: Allow signals tests to specify an expected si_code Mark Brown
2023-11-22 9:42 ` [PATCH v7 32/39] kselftest/arm64: Always run signals tests with GCS enabled Mark Brown
2023-11-22 9:42 ` [PATCH v7 33/39] kselftest/arm64: Add very basic GCS test program Mark Brown
2023-11-22 9:42 ` [PATCH v7 34/39] kselftest/arm64: Add a GCS test program built with the system libc Mark Brown
2023-12-15 2:50 ` Thiago Jung Bauermann
2023-12-15 14:59 ` Mark Brown
2023-12-17 2:18 ` Thiago Jung Bauermann
2024-01-18 19:58 ` Mark Brown
2023-11-22 9:42 ` [PATCH v7 35/39] kselftest/arm64: Add test coverage for GCS mode locking Mark Brown
2023-11-22 9:42 ` [PATCH v7 36/39] selftests/arm64: Add GCS signal tests Mark Brown
2023-12-17 2:12 ` Thiago Jung Bauermann
2024-01-18 21:10 ` Mark Brown
2023-11-22 9:42 ` [PATCH v7 37/39] kselftest/arm64: Add a GCS stress test Mark Brown
2023-12-13 2:45 ` Thiago Jung Bauermann
2023-11-22 9:42 ` [PATCH v7 38/39] kselftest/arm64: Enable GCS for the FP stress tests Mark Brown
2023-11-22 9:42 ` [PATCH v7 39/39] kselftest/clone3: Enable GCS in the clone3 selftests Mark Brown
2023-12-20 4:13 ` [PATCH v7 00/39] arm64/gcs: Provide support for GCS in userspace Thiago Jung Bauermann
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