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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Will Deacon <will.deacon@arm.com>,
	stable@vger.kernel.org,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: [PATCH 4.19 102/114] arm64: ssbs: Dont treat CPUs with SSBS as unaffected by SSB
Date: Thu, 10 Oct 2019 10:36:49 +0200	[thread overview]
Message-ID: <20191010083613.611304454@linuxfoundation.org> (raw)
In-Reply-To: <20191010083544.711104709@linuxfoundation.org>

From: Will Deacon <will.deacon@arm.com>

[ Upstream commit eb337cdfcd5dd3b10522c2f34140a73a4c285c30 ]

SSBS provides a relatively cheap mitigation for SSB, but it is still a
mitigation and its presence does not indicate that the CPU is unaffected
by the vulnerability.

Tweak the mitigation logic so that we report the correct string in sysfs.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/arm64/kernel/cpu_errata.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -341,15 +341,17 @@ static bool has_ssbd_mitigation(const st
 
 	WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
 
+	/* delay setting __ssb_safe until we get a firmware response */
+	if (is_midr_in_range_list(read_cpuid_id(), entry->midr_range_list))
+		this_cpu_safe = true;
+
 	if (this_cpu_has_cap(ARM64_SSBS)) {
+		if (!this_cpu_safe)
+			__ssb_safe = false;
 		required = false;
 		goto out_printmsg;
 	}
 
-	/* delay setting __ssb_safe until we get a firmware response */
-	if (is_midr_in_range_list(read_cpuid_id(), entry->midr_range_list))
-		this_cpu_safe = true;
-
 	if (psci_ops.smccc_version == SMCCC_VERSION_1_0) {
 		ssbd_state = ARM64_SSBD_UNKNOWN;
 		if (!this_cpu_safe)



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  parent reply	other threads:[~2019-10-10  8:51 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20191010083544.711104709@linuxfoundation.org>
2019-10-10  8:36 ` [PATCH 4.19 089/114] arm64: ssbd: Add support for PSTATE.SSBS rather than trapping to EL3 Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 090/114] KVM: arm64: Set SCTLR_EL2.DSSBS if SSBD is forcefully disabled and !vhe Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 091/114] arm64: docs: Document SSBS HWCAP Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 092/114] arm64: fix SSBS sanitization Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 093/114] arm64: Add sysfs vulnerability show for spectre-v1 Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 094/114] arm64: add sysfs vulnerability show for meltdown Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 095/114] arm64: enable generic CPU vulnerabilites support Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 096/114] arm64: Always enable ssb vulnerability detection Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 097/114] arm64: Provide a command line to disable spectre_v2 mitigation Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 098/114] arm64: Advertise mitigation of Spectre-v2, or lack thereof Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 099/114] arm64: Always enable spectre-v2 vulnerability detection Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 100/114] arm64: add sysfs vulnerability show for spectre-v2 Greg Kroah-Hartman
2019-10-10  8:36 ` [PATCH 4.19 101/114] arm64: add sysfs vulnerability show for speculative store bypass Greg Kroah-Hartman
2019-10-10  8:36 ` Greg Kroah-Hartman [this message]
2019-10-10  8:36 ` [PATCH 4.19 103/114] arm64: Force SSBS on context switch Greg Kroah-Hartman

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