From: Catalin Marinas <catalin.marinas@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Shuah Khan <skhan@linuxfoundation.org>,
Shuah Khan <shuah@kernel.org>,
Alan Hayward <alan.hayward@arm.com>,
Luis Machado <luis.machado@arm.com>,
Salil Akerkar <Salil.Akerkar@arm.com>,
Basant Kumar Dwivedi <Basant.KumarDwivedi@arm.com>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kselftest@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v12 20/40] arm64/sme: Implement streaming SVE signal handling
Date: Wed, 2 Mar 2022 17:09:32 +0000 [thread overview]
Message-ID: <Yh+kzH88WFFNde4r@arm.com> (raw)
In-Reply-To: <20220225165923.1474372-21-broonie@kernel.org>
On Fri, Feb 25, 2022 at 04:59:03PM +0000, Mark Brown wrote:
> When in streaming mode we have the same set of SVE registers as we do in
> regular SVE mode with the exception of FFR and the use of the SME vector
> length. Provide signal handling for these registers by taking one of the
> reserved words in the SVE signal context as a flags field and defining a
> flag which is set for streaming mode. When the flag is set the vector
> length is set to the streaming mode vector length and we save and
> restore streaming mode data. We support entering or leaving streaming
> mode based on the value of the flag but do not support changing the
> vector length, this is not currently supported SVE signal handling.
>
> We could instead allocate a separate record in the signal frame for the
> streaming mode SVE context but this inflates the size of the maximal signal
> frame required and adds complication when validating signal frames from
> userspace, especially given the current structure of the code.
>
> Any implementation of support for streaming mode vectors in signals will
> have some potential for causing issues for applications that attempt to
> handle SVE vectors in signals, use streaming mode but do not understand
> streaming mode in their signal handling code, it is hard to identify a
> case that is clearly better than any other - they all have cases where
> they could cause unexpected register corruption or faults.
>
> Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
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next prev parent reply other threads:[~2022-03-02 17:10 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-25 16:58 [PATCH v12 00/40] arm64/sme: Initial support for the Scalable Matrix Extension Mark Brown
2022-02-25 16:58 ` [PATCH v12 01/40] arm64: Define CPACR_EL1_FPEN similarly to other floating point controls Mark Brown
2022-02-25 16:58 ` [PATCH v12 02/40] arm64: Always use individual bits in CPACR floating point enables Mark Brown
2022-02-25 16:58 ` [PATCH v12 03/40] arm64: cpufeature: Always specify and use a field width for capabilities Mark Brown
2022-02-25 16:58 ` [PATCH v12 04/40] kselftest/arm64: Remove local ARRAY_SIZE() definitions Mark Brown
2022-02-25 16:58 ` [PATCH v12 05/40] kselftest/arm64: signal: Allow tests to be incompatible with features Mark Brown
2022-02-25 16:58 ` [PATCH v12 06/40] arm64/sme: Provide ABI documentation for SME Mark Brown
2022-03-02 17:23 ` Catalin Marinas
2022-03-11 17:21 ` Szabolcs Nagy
2022-03-11 18:42 ` Mark Brown
2022-03-31 16:05 ` Szabolcs Nagy
2022-04-06 18:50 ` Mark Brown
2022-04-07 15:26 ` Szabolcs Nagy
2022-06-06 10:35 ` Luis Machado
2022-02-25 16:58 ` [PATCH v12 07/40] arm64/sme: System register and exception syndrome definitions Mark Brown
2022-02-25 16:58 ` [PATCH v12 08/40] arm64/sme: Manually encode SME instructions Mark Brown
2022-03-02 14:35 ` Catalin Marinas
2022-02-25 16:58 ` [PATCH v12 09/40] arm64/sme: Early CPU setup for SME Mark Brown
2022-02-25 16:58 ` [PATCH v12 10/40] arm64/sme: Basic enumeration support Mark Brown
2022-03-02 16:29 ` Catalin Marinas
2022-02-25 16:58 ` [PATCH v12 11/40] arm64/sme: Identify supported SME vector lengths at boot Mark Brown
2022-03-02 16:41 ` Catalin Marinas
2022-03-16 21:32 ` Thiago Jung Bauermann
2022-02-25 16:58 ` [PATCH v12 12/40] arm64/sme: Implement sysctl to set the default vector length Mark Brown
2022-02-25 16:58 ` [PATCH v12 13/40] arm64/sme: Implement vector length configuration prctl()s Mark Brown
2022-02-25 16:58 ` [PATCH v12 14/40] arm64/sme: Implement support for TPIDR2 Mark Brown
2022-02-25 16:58 ` [PATCH v12 15/40] arm64/sme: Implement SVCR context switching Mark Brown
2022-02-25 16:58 ` [PATCH v12 16/40] arm64/sme: Implement streaming SVE " Mark Brown
2022-02-25 16:59 ` [PATCH v12 17/40] arm64/sme: Implement ZA " Mark Brown
2022-02-25 16:59 ` [PATCH v12 18/40] arm64/sme: Implement traps and syscall handling for SME Mark Brown
2022-03-02 17:07 ` Catalin Marinas
2022-02-25 16:59 ` [PATCH v12 19/40] arm64/sme: Disable ZA and streaming mode when handling signals Mark Brown
2022-02-25 16:59 ` [PATCH v12 20/40] arm64/sme: Implement streaming SVE signal handling Mark Brown
2022-03-02 17:09 ` Catalin Marinas [this message]
2022-03-16 22:38 ` Thiago Jung Bauermann
2022-02-25 16:59 ` [PATCH v12 21/40] arm64/sme: Implement ZA " Mark Brown
2022-02-25 16:59 ` [PATCH v12 22/40] arm64/sme: Implement ptrace support for streaming mode SVE registers Mark Brown
2022-03-02 17:11 ` Catalin Marinas
2022-02-25 16:59 ` [PATCH v12 23/40] arm64/sme: Add ptrace support for ZA Mark Brown
2022-03-15 21:51 ` Thiago Jung Bauermann
2022-02-25 16:59 ` [PATCH v12 24/40] arm64/sme: Disable streaming mode and ZA when flushing CPU state Mark Brown
2022-02-25 16:59 ` [PATCH v12 25/40] arm64/sme: Save and restore streaming mode over EFI runtime calls Mark Brown
2022-02-25 16:59 ` [PATCH v12 26/40] KVM: arm64: Hide SME system registers from guests Mark Brown
2022-02-25 16:59 ` [PATCH v12 27/40] KVM: arm64: Trap SME usage in guest Mark Brown
2022-02-25 16:59 ` [PATCH v12 28/40] KVM: arm64: Handle SME host state when running guests Mark Brown
2022-02-25 16:59 ` [PATCH v12 29/40] arm64/sme: Provide Kconfig for SME Mark Brown
2022-02-25 16:59 ` [PATCH v12 30/40] kselftest/arm64: Add manual encodings for SME instructions Mark Brown
2022-02-25 16:59 ` [PATCH v12 31/40] kselftest/arm64: sme: Add SME support to vlset Mark Brown
2022-02-25 16:59 ` [PATCH v12 32/40] kselftest/arm64: Add tests for TPIDR2 Mark Brown
2022-02-25 16:59 ` [PATCH v12 33/40] kselftest/arm64: Extend vector configuration API tests to cover SME Mark Brown
2022-02-25 16:59 ` [PATCH v12 34/40] kselftest/arm64: sme: Provide streaming mode SVE stress test Mark Brown
2022-02-25 16:59 ` [PATCH v12 35/40] kselftest/arm64: signal: Handle ZA signal context in core code Mark Brown
2022-02-25 16:59 ` [PATCH v12 36/40] kselftest/arm64: Add stress test for SME ZA context switching Mark Brown
2022-02-25 16:59 ` [PATCH v12 37/40] kselftest/arm64: signal: Add SME signal handling tests Mark Brown
2022-02-25 16:59 ` [PATCH v12 38/40] kselftest/arm64: Add streaming SVE to SVE ptrace tests Mark Brown
2022-02-25 16:59 ` [PATCH v12 39/40] kselftest/arm64: Add coverage for the ZA ptrace interface Mark Brown
2022-02-25 16:59 ` [PATCH v12 40/40] kselftest/arm64: Add SME support to syscall ABI test Mark Brown
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