From: Mark Brown <broonie@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Shuah Khan <skhan@linuxfoundation.org>,
Shuah Khan <shuah@kernel.org>
Cc: 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,
Mark Brown <broonie@kernel.org>
Subject: [PATCH v9 23/40] arm64/sme: Disable streaming mode and ZA when flushing CPU state
Date: Wed, 26 Jan 2022 15:11:03 +0000 [thread overview]
Message-ID: <20220126151120.3811248-24-broonie@kernel.org> (raw)
In-Reply-To: <20220126151120.3811248-1-broonie@kernel.org>
Both streaming mode and ZA may increase power consumption when they are
enabled and streaming mode makes many FPSIMD and SVE instructions undefined
which will cause problems for any kernel mode floating point so disable
both when we flush the CPU state. This covers both kernel_neon_begin() and
idle and after flushing the state a reload is always required anyway.
Signed-off-by: Mark Brown <broonie@kernel.org>
---
arch/arm64/kernel/fpsimd.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 8b111b7f2006..e00d3a9e919c 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -1762,6 +1762,15 @@ static void fpsimd_flush_cpu_state(void)
{
WARN_ON(!system_supports_fpsimd());
__this_cpu_write(fpsimd_last_state.st, NULL);
+
+ /*
+ * Leaving streaming mode enabled will cause issues for any kernel
+ * NEON and leaving streaming mode or ZA enabled may increase power
+ * consumption.
+ */
+ if (system_supports_sme())
+ sme_smstop();
+
set_thread_flag(TIF_FOREIGN_FPSTATE);
}
--
2.30.2
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next prev parent reply other threads:[~2022-01-26 15:50 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-26 15:10 [PATCH v9 00/40] arm64/sme: Initial support for the Scalable Matrix Extension Mark Brown
2022-01-26 15:10 ` [PATCH v9 01/40] arm64: Define CPACR_EL1_FPEN similarly to other floating point controls Mark Brown
2022-01-26 15:10 ` [PATCH v9 02/40] arm64: Always use individual bits in CPACR floating point enables Mark Brown
2022-01-26 15:10 ` [PATCH v9 03/40] arm64: cpufeature: Always specify and use a field width for capabilities Mark Brown
2022-01-26 15:10 ` [PATCH v9 04/40] kselftest/arm64: Remove local ARRAY_SIZE() definitions Mark Brown
2022-01-26 15:10 ` [PATCH v9 05/40] arm64/sme: Provide ABI documentation for SME Mark Brown
2022-01-26 15:10 ` [PATCH v9 06/40] arm64/sme: System register and exception syndrome definitions Mark Brown
2022-01-26 15:10 ` [PATCH v9 07/40] arm64/sme: Manually encode SME instructions Mark Brown
2022-01-26 15:10 ` [PATCH v9 08/40] arm64/sme: Early CPU setup for SME Mark Brown
2022-01-26 15:10 ` [PATCH v9 09/40] arm64/sme: Basic enumeration support Mark Brown
2022-01-26 15:10 ` [PATCH v9 10/40] arm64/sme: Identify supported SME vector lengths at boot Mark Brown
2022-01-26 15:10 ` [PATCH v9 11/40] arm64/sme: Implement sysctl to set the default vector length Mark Brown
2022-01-26 15:10 ` [PATCH v9 12/40] arm64/sme: Implement vector length configuration prctl()s Mark Brown
2022-01-26 15:10 ` [PATCH v9 13/40] arm64/sme: Implement support for TPIDR2 Mark Brown
2022-01-26 15:10 ` [PATCH v9 14/40] arm64/sme: Implement SVCR context switching Mark Brown
2022-01-26 15:10 ` [PATCH v9 15/40] arm64/sme: Implement streaming SVE " Mark Brown
2022-01-26 15:10 ` [PATCH v9 16/40] arm64/sme: Implement ZA " Mark Brown
2022-01-26 15:10 ` [PATCH v9 17/40] arm64/sme: Implement traps and syscall handling for SME Mark Brown
2022-01-26 15:10 ` [PATCH v9 18/40] arm64/sme: Disable ZA and streaming mode when handling signals Mark Brown
2022-01-26 15:10 ` [PATCH v9 19/40] arm64/sme: Implement streaming SVE signal handling Mark Brown
2022-01-26 15:11 ` [PATCH v9 20/40] arm64/sme: Implement ZA " Mark Brown
2022-01-26 15:11 ` [PATCH v9 21/40] arm64/sme: Implement ptrace support for streaming mode SVE registers Mark Brown
2022-01-26 15:11 ` [PATCH v9 22/40] arm64/sme: Add ptrace support for ZA Mark Brown
2022-01-26 15:11 ` Mark Brown [this message]
2022-01-26 15:11 ` [PATCH v9 24/40] arm64/sme: Save and restore streaming mode over EFI runtime calls Mark Brown
2022-01-26 15:11 ` [PATCH v9 25/40] KVM: arm64: Hide SME system registers from guests Mark Brown
2022-01-26 15:11 ` [PATCH v9 26/40] KVM: arm64: Trap SME usage in guest Mark Brown
2022-01-26 15:11 ` [PATCH v9 27/40] KVM: arm64: Handle SME host state when running guests Mark Brown
2022-01-26 15:11 ` [PATCH v9 28/40] arm64/sme: Provide Kconfig for SME Mark Brown
2022-01-26 15:11 ` [PATCH v9 29/40] kselftest/arm64: sme: Add streaming SME support to vlset Mark Brown
2022-01-26 15:11 ` [PATCH v9 30/40] kselftest/arm64: Add tests for TPIDR2 Mark Brown
2022-01-26 15:11 ` [PATCH v9 31/40] kselftest/arm64: Extend vector configuration API tests to cover SME Mark Brown
2022-01-26 15:11 ` [PATCH v9 32/40] kselftest/arm64: sme: Provide streaming mode SVE stress test Mark Brown
2022-01-26 15:11 ` [PATCH v9 33/40] kselftest/arm64: signal: Allow tests to be incompatible with features Mark Brown
2022-01-26 15:11 ` [PATCH v9 34/40] kselftest/arm64: signal: Handle ZA signal context in core code Mark Brown
2022-01-26 15:11 ` [PATCH v9 35/40] kselftest/arm64: Add stress test for SME ZA context switching Mark Brown
2022-01-26 15:11 ` [PATCH v9 36/40] kselftest/arm64: signal: Add SME signal handling tests Mark Brown
2022-01-26 15:11 ` [PATCH v9 37/40] kselftest/arm64: Add streaming SVE to SVE ptrace tests Mark Brown
2022-01-26 15:11 ` [PATCH v9 38/40] kselftest/arm64: Add coverage for the ZA ptrace interface Mark Brown
2022-01-26 15:11 ` [PATCH v9 39/40] kselftest/arm64: Add SME support to syscall ABI test Mark Brown
2022-01-26 15:11 ` [PATCH v9 40/40] squqsh traps Mark Brown
2022-01-26 15:24 ` Mark Brown
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