From: Andre Przywara <andre.przywara@arm.com>
To: Jeremy Linton <jeremy.linton@arm.com>,
linux-arm-kernel@lists.infradead.org
Cc: mlangsdo@redhat.com, suzuki.poulose@arm.com,
marc.zyngier@arm.com, catalin.marinas@arm.com,
julien.thierry@arm.com, will.deacon@arm.com,
linux-kernel@vger.kernel.org, stefan.wahren@i2e.com,
Dave.Martin@arm.com, shankerd@codeaurora.org
Subject: Re: [PATCH v5 05/10] arm64: Use firmware to detect CPUs that are not affected by Spectre-v2
Date: Fri, 1 Mar 2019 00:58:19 -0600 [thread overview]
Message-ID: <e1df235f-bcdd-62f0-7b2f-e396df6d9bae@foss.arm.com> (raw)
In-Reply-To: <20190227010544.597579-6-jeremy.linton@arm.com>
Hi,
On 2/26/19 7:05 PM, Jeremy Linton wrote:
> From: Marc Zyngier <marc.zyngier@arm.com>
>
> The SMCCC ARCH_WORKAROUND_1 service can indicate that although the
> firmware knows about the Spectre-v2 mitigation, this particular
> CPU is not vulnerable, and it is thus not necessary to call
> the firmware on this CPU.
>
> Let's use this information to our benefit.
Yes, that matches the firmware interface description.
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Cheers,
Andre.
> ---
> arch/arm64/kernel/cpu_errata.c | 32 +++++++++++++++++++++++---------
> 1 file changed, 23 insertions(+), 9 deletions(-)
>
> diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
> index c8972255b365..77f021e78a28 100644
> --- a/arch/arm64/kernel/cpu_errata.c
> +++ b/arch/arm64/kernel/cpu_errata.c
> @@ -230,22 +230,36 @@ static int detect_harden_bp_fw(void)
> case PSCI_CONDUIT_HVC:
> arm_smccc_1_1_hvc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
> ARM_SMCCC_ARCH_WORKAROUND_1, &res);
> - if ((int)res.a0 < 0)
> + switch ((int)res.a0) {
> + case 1:
> + /* Firmware says we're just fine */
> + return 0;
> + case 0:
> + cb = call_hvc_arch_workaround_1;
> + /* This is a guest, no need to patch KVM vectors */
> + smccc_start = NULL;
> + smccc_end = NULL;
> + break;
> + default:
> return -1;
> - cb = call_hvc_arch_workaround_1;
> - /* This is a guest, no need to patch KVM vectors */
> - smccc_start = NULL;
> - smccc_end = NULL;
> + }
> break;
>
> case PSCI_CONDUIT_SMC:
> arm_smccc_1_1_smc(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
> ARM_SMCCC_ARCH_WORKAROUND_1, &res);
> - if ((int)res.a0 < 0)
> + switch ((int)res.a0) {
> + case 1:
> + /* Firmware says we're just fine */
> + return 0;
> + case 0:
> + cb = call_smc_arch_workaround_1;
> + smccc_start = __smccc_workaround_1_smc_start;
> + smccc_end = __smccc_workaround_1_smc_end;
> + break;
> + default:
> return -1;
> - cb = call_smc_arch_workaround_1;
> - smccc_start = __smccc_workaround_1_smc_start;
> - smccc_end = __smccc_workaround_1_smc_end;
> + }
> break;
>
> default:
>
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next prev parent reply other threads:[~2019-03-01 6:58 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-27 1:05 [PATCH v5 00/10] arm64: add system vulnerability sysfs entries Jeremy Linton
2019-02-27 1:05 ` [PATCH v5 01/10] arm64: Provide a command line to disable spectre_v2 mitigation Jeremy Linton
2019-02-28 18:14 ` Suzuki K Poulose
2019-02-28 18:21 ` Catalin Marinas
2019-02-28 18:25 ` Suzuki K Poulose
2019-03-01 6:54 ` Andre Przywara
2019-02-27 1:05 ` [PATCH v5 02/10] arm64: add sysfs vulnerability show for spectre v1 Jeremy Linton
2019-02-28 18:29 ` Suzuki K Poulose
2019-03-01 6:54 ` Andre Przywara
2019-02-27 1:05 ` [PATCH v5 03/10] arm64: add sysfs vulnerability show for meltdown Jeremy Linton
2019-02-28 18:33 ` Suzuki K Poulose
2019-03-01 7:11 ` Andre Przywara
2019-03-01 16:12 ` Jeremy Linton
2019-03-01 16:20 ` Catalin Marinas
2019-03-01 16:53 ` Jeremy Linton
2019-03-01 17:15 ` Catalin Marinas
2019-03-01 17:30 ` Andre Przywara
2019-02-27 1:05 ` [PATCH v5 04/10] arm64: Advertise mitigation of Spectre-v2, or lack thereof Jeremy Linton
2019-03-01 6:57 ` Andre Przywara
2019-02-27 1:05 ` [PATCH v5 05/10] arm64: Use firmware to detect CPUs that are not affected by Spectre-v2 Jeremy Linton
2019-03-01 6:58 ` Andre Przywara [this message]
2019-02-27 1:05 ` [PATCH v5 06/10] arm64: Always enable spectrev2 vulnerability detection Jeremy Linton
2019-03-01 6:58 ` Andre Przywara
2019-02-27 1:05 ` [PATCH v5 07/10] arm64: add sysfs vulnerability show for spectre v2 Jeremy Linton
2019-03-01 6:59 ` Andre Przywara
2019-02-27 1:05 ` [PATCH v5 08/10] arm64: Always enable ssb vulnerability detection Jeremy Linton
2019-03-01 7:02 ` Andre Przywara
2019-03-01 16:16 ` Jeremy Linton
2019-02-27 1:05 ` [PATCH v5 09/10] arm64: add sysfs vulnerability show for speculative store bypass Jeremy Linton
2019-03-01 7:02 ` Andre Przywara
2019-03-01 16:41 ` Jeremy Linton
2019-02-27 1:05 ` [PATCH v5 10/10] arm64: enable generic CPU vulnerabilites support Jeremy Linton
2019-03-01 7:03 ` Andre Przywara
2019-02-28 12:01 ` [PATCH v5 00/10] arm64: add system vulnerability sysfs entries Catalin Marinas
2019-03-01 19:35 ` Stefan Wahren
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