From: Mark Brown <broonie@kernel.org>
To: Alan Hayward <Alan.Hayward@arm.com>
Cc: Catalin Marinas <Catalin.Marinas@arm.com>,
Will Deacon <will@kernel.org>,
Shuah Khan <skhan@linuxfoundation.org>,
Shuah Khan <shuah@kernel.org>,
Luis Machado <Luis.Machado@arm.com>,
Salil Akerkar <Salil.Akerkar@arm.com>,
Basant KumarDwivedi <Basant.KumarDwivedi@arm.com>,
Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kselftest@vger.kernel.org"
<linux-kselftest@vger.kernel.org>, nd <nd@arm.com>
Subject: Re: [PATCH v1 12/38] arm64/sme: Provide ABI documentation for SME
Date: Fri, 8 Oct 2021 18:04:42 +0100 [thread overview]
Message-ID: <YWB6KmvHGfYBBoxK@sirena.org.uk> (raw)
In-Reply-To: <0749CCC0-CCEF-4869-9F55-FD9AC97CBA67@arm.com>
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On Fri, Oct 08, 2021 at 04:45:44PM +0000, Alan Hayward wrote:
> > On 8 Oct 2021, at 16:28, Mark Brown <broonie@kernel.org> wrote:
> > On Fri, Oct 08, 2021 at 02:11:46PM +0000, Alan Hayward wrote:
> >> Can NT_ARM_SSVE return a fpsimd?
> > It's documented that way for simplicity but in the current
> > implementation it won't ever actually do so in practice. The
> > only case where I could see that it might happen would be if we
> > change the syscalls to stay in streaming mode over syscall, in
> > that case we could do as we do for SVE and preserve FPSIMD
> > registers only. At present we drop out of streaming mode if we
> > get a syscall with it enabled so it's a non-issue, if people
> > agree that that's the right thing for the syscalls then we should
> > update the documentation to specify this since otherwise we'll
> > doubtless catch someone by surprise if we ever manage to start
> > doing it in the future.
> ….or it’ll end up executing some code that was written to cope with fpsimd, but has never been
> run. Might be worth making it explicit in the documentation.
I will if/when it gets fixed that way. Actually, while looking
at that code I was tempted to remove the support for returning
FPSIMD only registers via NT_ARM_SVE entirely and just always
convert to SVE format - I'm not sure what the use case was there?
It's not a pressing thing but it seemed like it was a bit of an
implementation detail that we were revealing.
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next prev parent reply other threads:[~2021-10-08 17:04 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-30 18:11 [PATCH v1 00/38] arm64/sme: Initial support for the Scalable Matrix Extension Mark Brown
2021-09-30 18:11 ` [PATCH v1 01/38] arm64/fp: Reindent fpsimd_save() Mark Brown
2021-10-11 9:39 ` Jonathan Cameron
2021-10-11 13:02 ` Mark Brown
2021-09-30 18:11 ` [PATCH v1 02/38] arm64/sve: Remove sve_load_from_fpsimd_state() Mark Brown
2021-09-30 18:11 ` [PATCH v1 03/38] arm64/sve: Make access to FFR optional Mark Brown
2021-09-30 18:11 ` [PATCH v1 04/38] arm64/sve: Rename find_supported_vector_length() Mark Brown
2021-09-30 18:11 ` [PATCH v1 05/38] arm64/sve: Use accessor functions for vector lengths in thread_struct Mark Brown
2021-09-30 18:11 ` [PATCH v1 06/38] arm64/sve: Put system wide vector length information into structs Mark Brown
2021-10-01 3:13 ` kernel test robot
2021-09-30 18:11 ` [PATCH v1 07/38] arm64/sve: Explicitly load vector length when restoring SVE state Mark Brown
2021-09-30 18:11 ` [PATCH v1 08/38] arm64/sve: Track vector lengths for tasks in an array Mark Brown
2021-10-11 10:20 ` Jonathan Cameron
2021-10-11 13:14 ` Mark Brown
2021-10-11 13:18 ` Jonathan Cameron
2021-09-30 18:11 ` [PATCH v1 09/38] arm64/sve: Make sysctl interface for SVE reusable by SME Mark Brown
2021-09-30 18:11 ` [PATCH v1 10/38] arm64/sve: Generalise vector length configuration prctl() for SME Mark Brown
2021-10-11 10:27 ` Jonathan Cameron
2021-10-11 13:18 ` Mark Brown
2021-09-30 18:11 ` [PATCH v1 11/38] selftests: arm64: Parameterise ptrace vector length information Mark Brown
2021-09-30 18:11 ` [PATCH v1 12/38] arm64/sme: Provide ABI documentation for SME Mark Brown
2021-10-08 14:11 ` Alan Hayward
2021-10-08 15:28 ` Mark Brown
2021-10-08 16:45 ` Alan Hayward
2021-10-08 17:04 ` Mark Brown [this message]
2021-10-11 11:15 ` Alan Hayward
2021-10-11 11:48 ` Mark Brown
2021-10-11 11:05 ` Jonathan Cameron
2021-10-11 13:20 ` Mark Brown
2021-10-11 13:17 ` Szabolcs Nagy
2021-10-11 13:23 ` Mark Brown
2021-10-11 14:19 ` Szabolcs Nagy
2021-10-11 20:10 ` Mark Brown
2021-10-12 8:23 ` Szabolcs Nagy
2021-10-13 18:37 ` Mark Brown
2021-10-14 9:57 ` Szabolcs Nagy
2021-09-30 18:11 ` [PATCH v1 13/38] arm64/sme: System register and exception syndrome definitions Mark Brown
2021-09-30 18:11 ` [PATCH v1 14/38] arm64/sme: Define macros for manually encoding SME instructions Mark Brown
2021-09-30 18:11 ` [PATCH v1 15/38] arm64/sme: Early CPU setup for SME Mark Brown
2021-09-30 18:11 ` [PATCH v1 16/38] arm64/sme: Basic enumeration support Mark Brown
2021-09-30 18:11 ` [PATCH v1 17/38] arm64/sme: Identify supported SME vector lengths at boot Mark Brown
2021-09-30 18:11 ` [PATCH v1 18/38] arm64/sme: Implement sysctl to set the default vector length Mark Brown
2021-09-30 18:11 ` [PATCH v1 19/38] arm64/sme: Implement vector length configuration prctl()s Mark Brown
2021-10-01 5:20 ` kernel test robot
2021-10-01 12:40 ` Mark Brown
2021-10-08 1:32 ` [kbuild-all] " Chen, Rong A
2021-10-01 16:38 ` kernel test robot
2021-09-30 18:11 ` [PATCH v1 20/38] arm64/sme: Implement support for TPIDR2 Mark Brown
2021-09-30 18:11 ` [PATCH v1 21/38] arm64/sme: Implement SVCR context switching Mark Brown
2021-10-11 12:15 ` Jonathan Cameron
2021-09-30 18:11 ` [PATCH v1 22/38] arm64/sme: Implement streaming SVE " Mark Brown
2021-09-30 18:11 ` [PATCH v1 23/38] arm64/sme: Implement ZA " Mark Brown
2021-10-11 12:27 ` Jonathan Cameron
2021-09-30 18:11 ` [PATCH v1 24/38] arm64/sme: Implement traps and syscall handling for SME Mark Brown
2021-10-11 12:37 ` Jonathan Cameron
2021-09-30 18:11 ` [PATCH v1 25/38] arm64/sme: Implement streaming SVE signal handling Mark Brown
2021-09-30 18:11 ` [PATCH v1 26/38] arm64/sme: Implement ZA " Mark Brown
2021-09-30 18:11 ` [PATCH v1 27/38] arm64/sme: Implement ptrace support for streaming mode SVE registers Mark Brown
2021-09-30 18:11 ` [PATCH v1 28/38] arm64/sme: Add ptrace support for ZA Mark Brown
2021-09-30 18:11 ` [PATCH v1 29/38] arm64/sme: Disable streaming mode and ZA when flushing CPU state Mark Brown
2021-09-30 18:11 ` [PATCH v1 30/38] arm64/sme: Save and restore streaming mode over EFI runtime calls Mark Brown
2021-09-30 18:11 ` [PATCH v1 31/38] arm64/sme: Provide Kconfig for SME Mark Brown
2021-09-30 18:11 ` [PATCH v1 32/38] kselftest/arm64: Add tests for TPIDR2 Mark Brown
2021-09-30 18:11 ` [PATCH v1 33/38] kselftest/arm64: Extend vector configuration API tests to cover SME Mark Brown
2021-09-30 18:11 ` [PATCH v1 34/38] kselftest/arm64: sme: Provide streaming mode SVE stress test Mark Brown
2021-09-30 18:11 ` [PATCH v1 35/38] kselftest/arm64: Add stress test for SME ZA context switching Mark Brown
2021-09-30 18:11 ` [PATCH v1 36/38] kselftest/arm64: signal: Add SME signal handling tests Mark Brown
2021-09-30 18:11 ` [PATCH v1 37/38] selftests: arm64: Add streaming SVE to SVE ptrace tests Mark Brown
2021-09-30 18:11 ` [PATCH v1 38/38] selftests: arm64: Add coverage for the ZA ptrace interface Mark Brown
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