From: Jeremy Linton <jeremy.linton@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: catalin.marinas@arm.com, will.deacon@arm.com,
marc.zyngier@arm.com, suzuki.poulose@arm.com,
Dave.Martin@arm.com, shankerd@codeaurora.org,
julien.thierry@arm.com, mlangsdo@redhat.com,
stefan.wahren@i2se.com, Andre.Przywara@arm.com,
linux-kernel@vger.kernel.org,
Jeremy Linton <jeremy.linton@arm.com>,
Andre Przywara <andre.przywara@arm.com>
Subject: [v7 05/10] arm64: Use firmware to detect CPUs that are not affected by Spectre-v2
Date: Wed, 10 Apr 2019 18:12:32 -0500 [thread overview]
Message-ID: <20190410231237.52506-6-jeremy.linton@arm.com> (raw)
In-Reply-To: <20190410231237.52506-1-jeremy.linton@arm.com>
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.
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>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
---
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 2b6e6d8e105b..e5c4c5d84a4e 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:
--
2.20.1
next prev parent reply other threads:[~2019-04-10 23:13 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-10 23:12 [v7 00/10] arm64: add system vulnerability sysfs entries Jeremy Linton
2019-04-10 0:48 ` Jeremy Linton
2019-04-10 23:12 ` [v7 01/10] arm64: Provide a command line to disable spectre_v2 mitigation Jeremy Linton
2019-04-10 23:12 ` [v7 02/10] arm64: add sysfs vulnerability show for spectre v1 Jeremy Linton
2019-04-10 23:12 ` [v7 03/10] arm64: add sysfs vulnerability show for meltdown Jeremy Linton
2019-04-10 23:12 ` [v7 04/10] arm64: Advertise mitigation of Spectre-v2, or lack thereof Jeremy Linton
2019-04-10 23:12 ` Jeremy Linton [this message]
2019-04-10 23:12 ` [v7 06/10] arm64: Always enable spectrev2 vulnerability detection Jeremy Linton
2019-04-10 23:12 ` [v7 07/10] arm64: add sysfs vulnerability show for spectre v2 Jeremy Linton
2019-04-10 23:12 ` [v7 08/10] arm64: Always enable ssb vulnerability detection Jeremy Linton
2019-04-10 23:12 ` [v7 09/10] arm64: add sysfs vulnerability show for speculative store bypass Jeremy Linton
2019-04-10 23:12 ` [v7 10/10] arm64: enable generic CPU vulnerabilites support Jeremy Linton
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