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@i2e.com, Andre.Przywara@arm.com,
linux-kernel@vger.kernel.org,
Jeremy Linton <jeremy.linton@arm.com>,
Andre Przywara <andre.przywara@arm.com>,
Stefan Wahren <stefan.wahren@i2se.com>,
Jonathan Corbet <corbet@lwn.net>,
linux-doc@vger.kernel.org
Subject: [PATCH v6 01/10] arm64: Provide a command line to disable spectre_v2 mitigation
Date: Thu, 21 Mar 2019 18:05:48 -0500 [thread overview]
Message-ID: <20190321230557.45107-2-jeremy.linton@arm.com> (raw)
In-Reply-To: <20190321230557.45107-1-jeremy.linton@arm.com>
There are various reasons, including bencmarking, to disable spectrev2
mitigation on a machine. Provide a command-line to do so.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
---
Documentation/admin-guide/kernel-parameters.txt | 8 ++++----
arch/arm64/kernel/cpu_errata.c | 13 +++++++++++++
2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 2b8ee90bb644..d153bb15c8c7 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2873,10 +2873,10 @@
check bypass). With this option data leaks are possible
in the system.
- nospectre_v2 [X86,PPC_FSL_BOOK3E] Disable all mitigations for the Spectre variant 2
- (indirect branch prediction) vulnerability. System may
- allow data leaks with this option, which is equivalent
- to spectre_v2=off.
+ nospectre_v2 [X86,PPC_FSL_BOOK3E,ARM64] Disable all mitigations for
+ the Spectre variant 2 (indirect branch prediction)
+ vulnerability. System may allow data leaks with this
+ option.
nospec_store_bypass_disable
[HW] Disable all mitigations for the Speculative Store Bypass vulnerability
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 9950bb0cbd52..d2b2c69d31bb 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -220,6 +220,14 @@ static void qcom_link_stack_sanitization(void)
: "=&r" (tmp));
}
+static bool __nospectre_v2;
+static int __init parse_nospectre_v2(char *str)
+{
+ __nospectre_v2 = true;
+ return 0;
+}
+early_param("nospectre_v2", parse_nospectre_v2);
+
static void
enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
{
@@ -231,6 +239,11 @@ enable_smccc_arch_workaround_1(const struct arm64_cpu_capabilities *entry)
if (!entry->matches(entry, SCOPE_LOCAL_CPU))
return;
+ if (__nospectre_v2) {
+ pr_info_once("spectrev2 mitigation disabled by command line option\n");
+ return;
+ }
+
if (psci_ops.smccc_version == SMCCC_VERSION_1_0)
return;
--
2.20.1
next prev parent reply other threads:[~2019-03-21 23:06 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-21 23:05 [PATCH v6 00/10] arm64: add system vulnerability sysfs entries Jeremy Linton
2019-03-21 23:05 ` Jeremy Linton [this message]
2019-03-21 23:05 ` [PATCH v6 02/10] arm64: add sysfs vulnerability show for spectre v1 Jeremy Linton
2019-03-21 23:05 ` [PATCH v6 03/10] arm64: add sysfs vulnerability show for meltdown Jeremy Linton
2019-03-25 10:32 ` Andre Przywara
2019-03-21 23:05 ` [PATCH v6 04/10] arm64: Advertise mitigation of Spectre-v2, or lack thereof Jeremy Linton
2019-03-25 10:59 ` Suzuki K Poulose
2019-03-21 23:05 ` [PATCH v6 05/10] arm64: Use firmware to detect CPUs that are not affected by Spectre-v2 Jeremy Linton
2019-03-21 23:05 ` [PATCH v6 06/10] arm64: Always enable spectrev2 vulnerability detection Jeremy Linton
2019-03-21 23:05 ` [PATCH v6 07/10] arm64: add sysfs vulnerability show for spectre v2 Jeremy Linton
2019-03-21 23:05 ` [PATCH v6 08/10] arm64: Always enable ssb vulnerability detection Jeremy Linton
2019-03-21 23:05 ` [PATCH v6 09/10] arm64: add sysfs vulnerability show for speculative store bypass Jeremy Linton
2019-04-03 16:50 ` Will Deacon
2019-04-05 10:10 ` Andre Przywara
2019-04-05 14:43 ` Will Deacon
2019-04-05 15:18 ` Andre Przywara
2019-04-05 16:01 ` Jeremy Linton
2019-03-21 23:05 ` [PATCH v6 10/10] arm64: enable generic CPU vulnerabilites support Jeremy Linton
2019-03-22 17:49 ` Stefan Wahren
2019-03-25 10:33 ` [PATCH v6 00/10] arm64: add system vulnerability sysfs entries Andre Przywara
2019-03-25 12:22 ` Catalin Marinas
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