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>,
Luca Salabrino <luca.scalabrino@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kselftest@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v14 04/39] arm64/sme: Provide ABI documentation for SME
Date: Thu, 28 Apr 2022 10:19:22 +0100 [thread overview]
Message-ID: <YmpcGpSYpoiprngy@arm.com> (raw)
In-Reply-To: <20220419112247.711548-5-broonie@kernel.org>
On Tue, Apr 19, 2022 at 12:22:12PM +0100, Mark Brown wrote:
> +* There are a number of optional SME features, presence of these is reported
> + through AT_HWCAP2 through:
> +
> + HWCAP2_SME_I16I64
> + HWCAP2_SME_F64F64
> + HWCAP2_SME_I8I32
> + HWCAP2_SME_F16F32
> + HWCAP2_SME_B16F32
> + HWCAP2_SME_F32F32
> + HWCAP2_SME_FA64
Marc pointed out that in combination with FEAT_WFxT, we used all the
HWCAP2 bits (32). While we are ok for now, we'll soon need to look into
what to do when the next features turn up. Some options:
1. Only provide HWCAP2_SME and let the ID_AA64SMFR0_EL1 features be
probed via MRS emulation. It doesn't solve the problem but it buys us
a bit of time.
2. Don't bother with any new HWCAPs, just rely on MRS emulation (we have
HWCAP_CPUID advertising this).
3. Start using the upper 32-bit of HWCAP and HWCAP2 (we initially didn't
go into these as there was a slight chance of merging ILP32). Does
the libc rely on the upper bits for anything? Or does it just assume
a 32-bit HWCAPs layout?
4. Introduce HWCAP3.
Szabolcs, any thoughts?
Thanks.
--
Catalin
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next prev parent reply other threads:[~2022-04-28 9:20 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-19 11:22 [PATCH v14 00/39] arm64/sme: Initial support for the Scalable Matrix Extension Mark Brown
2022-04-19 11:22 ` [PATCH v14 01/39] kselftest/arm64: Fix comment for ptrace_sve_get_fpsimd_data() Mark Brown
2022-04-19 11:22 ` [PATCH v14 02/39] kselftest/arm64: Remove assumption that tasks start FPSIMD only Mark Brown
2022-04-19 11:22 ` [PATCH v14 03/39] kselftest/arm64: Validate setting via FPSIMD and read via SVE regsets Mark Brown
2022-04-19 11:22 ` [PATCH v14 04/39] arm64/sme: Provide ABI documentation for SME Mark Brown
2022-04-28 9:19 ` Catalin Marinas [this message]
2022-05-03 8:13 ` Szabolcs Nagy
2022-04-19 11:22 ` [PATCH v14 05/39] arm64/sme: System register and exception syndrome definitions Mark Brown
2022-04-19 11:22 ` [PATCH v14 06/39] arm64/sme: Manually encode SME instructions Mark Brown
2022-04-19 11:22 ` [PATCH v14 07/39] arm64/sme: Early CPU setup for SME Mark Brown
2022-04-19 11:22 ` [PATCH v14 08/39] arm64/sme: Basic enumeration support Mark Brown
2022-04-19 11:22 ` [PATCH v14 09/39] arm64/sme: Identify supported SME vector lengths at boot Mark Brown
2022-04-19 11:22 ` [PATCH v14 10/39] arm64/sme: Implement sysctl to set the default vector length Mark Brown
2022-04-19 11:22 ` [PATCH v14 11/39] arm64/sme: Implement vector length configuration prctl()s Mark Brown
2022-04-19 11:22 ` [PATCH v14 12/39] arm64/sme: Implement support for TPIDR2 Mark Brown
2022-04-19 11:22 ` [PATCH v14 13/39] arm64/sme: Implement SVCR context switching Mark Brown
2022-04-19 11:22 ` [PATCH v14 14/39] arm64/sme: Implement streaming SVE " Mark Brown
2022-04-19 11:22 ` [PATCH v14 15/39] arm64/sme: Implement ZA " Mark Brown
2022-04-19 11:22 ` [PATCH v14 16/39] arm64/sme: Implement traps and syscall handling for SME Mark Brown
2022-04-22 16:28 ` Catalin Marinas
2022-12-07 14:00 ` Zenghui Yu
2022-12-07 14:16 ` Mark Brown
2022-12-08 2:15 ` Zenghui Yu
2022-04-19 11:22 ` [PATCH v14 17/39] arm64/sme: Disable ZA and streaming mode when handling signals Mark Brown
2022-04-19 11:22 ` [PATCH v14 18/39] arm64/sme: Implement streaming SVE signal handling Mark Brown
2022-04-19 11:22 ` [PATCH v14 19/39] arm64/sme: Implement ZA " Mark Brown
2022-04-19 11:22 ` [PATCH v14 20/39] arm64/sme: Implement ptrace support for streaming mode SVE registers Mark Brown
2022-04-19 11:22 ` [PATCH v14 21/39] arm64/sme: Add ptrace support for ZA Mark Brown
2022-04-19 11:22 ` [PATCH v14 22/39] arm64/sme: Disable streaming mode and ZA when flushing CPU state Mark Brown
2022-04-19 11:22 ` [PATCH v14 23/39] arm64/sme: Save and restore streaming mode over EFI runtime calls Mark Brown
2022-04-19 11:22 ` [PATCH v14 24/39] KVM: arm64: Hide SME system registers from guests Mark Brown
2022-04-19 11:22 ` [PATCH v14 25/39] KVM: arm64: Trap SME usage in guest Mark Brown
2022-04-19 11:22 ` [PATCH v14 26/39] KVM: arm64: Handle SME host state when running guests Mark Brown
2022-04-19 11:22 ` [PATCH v14 27/39] arm64/sme: Provide Kconfig for SME Mark Brown
[not found] ` <CGME20220426221433eucas1p253f6350eacf87d8cac2c05adc903656e@eucas1p2.samsung.com>
2022-04-26 22:14 ` Marek Szyprowski
2022-04-27 12:55 ` Mark Brown
2022-04-19 11:22 ` [PATCH v14 28/39] kselftest/arm64: Add manual encodings for SME instructions Mark Brown
2022-04-19 11:22 ` [PATCH v14 29/39] kselftest/arm64: sme: Add SME support to vlset Mark Brown
2022-04-19 11:22 ` [PATCH v14 30/39] kselftest/arm64: Add tests for TPIDR2 Mark Brown
2022-04-19 11:22 ` [PATCH v14 31/39] kselftest/arm64: Extend vector configuration API tests to cover SME Mark Brown
2022-04-19 11:22 ` [PATCH v14 32/39] kselftest/arm64: sme: Provide streaming mode SVE stress test Mark Brown
2022-04-19 11:22 ` [PATCH v14 33/39] kselftest/arm64: signal: Handle ZA signal context in core code Mark Brown
2022-04-19 11:22 ` [PATCH v14 34/39] kselftest/arm64: Add stress test for SME ZA context switching Mark Brown
2022-04-19 11:22 ` [PATCH v14 35/39] kselftest/arm64: signal: Add SME signal handling tests Mark Brown
2022-04-19 11:22 ` [PATCH v14 36/39] kselftest/arm64: Add streaming SVE to SVE ptrace tests Mark Brown
2022-04-19 11:22 ` [PATCH v14 37/39] kselftest/arm64: Add coverage for the ZA ptrace interface Mark Brown
2022-04-19 11:22 ` [PATCH v14 38/39] kselftest/arm64: Add SME support to syscall ABI test Mark Brown
2022-04-19 11:22 ` [PATCH v14 39/39] selftests/arm64: Add a testcase for handling of ZA on clone() Mark Brown
2022-04-22 17:10 ` [PATCH v14 00/39] arm64/sme: Initial support for the Scalable Matrix Extension Marc Zyngier
2022-04-22 18:35 ` Catalin Marinas
2022-04-22 18:26 ` (subset) " Catalin Marinas
2022-04-27 17:08 ` Qian Cai
2022-04-27 17:14 ` Mark Brown
2022-04-27 21:08 ` Qian Cai
2022-04-27 22:13 ` Mark Brown
2022-05-03 22:23 ` Qian Cai
2022-05-03 23:52 ` Mark Brown
2022-05-04 5:25 ` Naresh Kamboju
2022-05-04 7:49 ` Naresh Kamboju
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