From: Jeremy Linton <jeremy.linton@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: stefan.wahren@i2se.com, 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,
Jeremy Linton <jeremy.linton@arm.com>,
steven.price@arm.com, ykaukab@suse.de, dave.martin@arm.com,
shankerd@codeaurora.org
Subject: [PATCH v4 11/12] arm64: add sysfs vulnerability show for speculative store bypass
Date: Fri, 25 Jan 2019 12:07:10 -0600 [thread overview]
Message-ID: <20190125180711.1970973-12-jeremy.linton@arm.com> (raw)
In-Reply-To: <20190125180711.1970973-1-jeremy.linton@arm.com>
Return status based on ssbd_state and the arm64 SSBS feature. If
the mitigation is disabled, or the firmware isn't responding then
return the expected machine state based on a new blacklist of known
vulnerable cores.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
---
arch/arm64/kernel/cpu_errata.c | 45 ++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index caedf268c972..e9ae8e5fd7e1 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -265,6 +265,7 @@ static int detect_harden_bp_fw(void)
DEFINE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required);
int ssbd_state __read_mostly = ARM64_SSBD_KERNEL;
+static bool __ssb_safe = true;
static const struct ssbd_options {
const char *str;
@@ -362,10 +363,16 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
{
struct arm_smccc_res res;
bool required = true;
+ bool is_vul;
s32 val;
WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
+ is_vul = is_midr_in_range_list(read_cpuid_id(), entry->midr_range_list);
+
+ if (is_vul)
+ __ssb_safe = false;
+
if (this_cpu_has_cap(ARM64_SSBS)) {
required = false;
goto out_printmsg;
@@ -399,6 +406,7 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
ssbd_state = ARM64_SSBD_UNKNOWN;
return false;
+ /* machines with mixed mitigation requirements must not return this */
case SMCCC_RET_NOT_REQUIRED:
pr_info_once("%s mitigation not required\n", entry->desc);
ssbd_state = ARM64_SSBD_MITIGATED;
@@ -454,6 +462,16 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
return required;
}
+/* known vulnerable cores */
+static const struct midr_range arm64_ssb_cpus[] = {
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A75),
+ MIDR_ALL_VERSIONS(MIDR_CORTEX_A76),
+ {},
+};
+
static void __maybe_unused
cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused)
{
@@ -743,6 +761,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
.capability = ARM64_SSBD,
.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
.matches = has_ssbd_mitigation,
+ .midr_range_list = arm64_ssb_cpus,
},
#ifdef CONFIG_ARM64_ERRATUM_1188873
{
@@ -784,4 +803,30 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr,
return sprintf(buf, "Vulnerable\n");
}
+ssize_t cpu_show_spec_store_bypass(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ /*
+ * Two assumptions: First, get_ssbd_state() reflects the worse case
+ * for hetrogenous machines, and that if SSBS is supported its
+ * supported by all cores.
+ */
+ switch (arm64_get_ssbd_state()) {
+ case ARM64_SSBD_MITIGATED:
+ return sprintf(buf, "Not affected\n");
+
+ case ARM64_SSBD_KERNEL:
+ case ARM64_SSBD_FORCE_ENABLE:
+ if (cpus_have_cap(ARM64_SSBS))
+ return sprintf(buf, "Not affected\n");
+ return sprintf(buf,
+ "Mitigation: Speculative Store Bypass disabled\n");
+ }
+
+ if (__ssb_safe)
+ return sprintf(buf, "Not affected\n");
+
+ return sprintf(buf, "Vulnerable\n");
+}
+
#endif
--
2.17.2
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next prev parent reply other threads:[~2019-01-25 18:10 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-25 18:06 [PATCH v4 00/12] arm64: add system vulnerability sysfs entries Jeremy Linton
2019-01-25 18:07 ` [PATCH v4 01/12] Documentation: Document arm64 kpti control Jeremy Linton
2019-01-30 18:02 ` Andre Przywara
2019-02-06 19:24 ` Jeremy Linton
2019-02-06 21:06 ` André Przywara
2019-01-31 17:58 ` Andre Przywara
2019-02-07 0:25 ` Jonathan Corbet
2019-01-25 18:07 ` [PATCH v4 02/12] arm64: Provide a command line to disable spectre_v2 mitigation Jeremy Linton
2019-01-30 18:03 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 03/12] arm64: Remove the ability to build a kernel without ssbd Jeremy Linton
2019-01-30 18:04 ` Andre Przywara
2019-02-15 18:20 ` Catalin Marinas
2019-02-15 18:54 ` Jeremy Linton
2019-01-25 18:07 ` [PATCH v4 04/12] arm64: remove the ability to build a kernel without hardened branch predictors Jeremy Linton
2019-01-30 18:04 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 05/12] arm64: remove the ability to build a kernel without kpti Jeremy Linton
2019-01-30 18:05 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 06/12] arm64: add sysfs vulnerability show for spectre v1 Jeremy Linton
2019-01-31 17:52 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 07/12] arm64: add sysfs vulnerability show for meltdown Jeremy Linton
2019-01-31 9:28 ` Julien Thierry
2019-01-31 21:48 ` Jeremy Linton
2019-01-31 17:54 ` Andre Przywara
2019-01-31 21:53 ` Jeremy Linton
2019-01-25 18:07 ` [PATCH v4 08/12] arm64: Advertise mitigation of Spectre-v2, or lack thereof Jeremy Linton
2019-01-31 17:54 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 09/12] arm64: Use firmware to detect CPUs that are not affected by Spectre-v2 Jeremy Linton
2019-01-31 17:55 ` Andre Przywara
2019-01-25 18:07 ` [PATCH v4 10/12] arm64: add sysfs vulnerability show for spectre v2 Jeremy Linton
2019-01-31 17:55 ` Andre Przywara
2019-01-25 18:07 ` Jeremy Linton [this message]
2019-01-31 17:55 ` [PATCH v4 11/12] arm64: add sysfs vulnerability show for speculative store bypass Andre Przywara
2019-01-25 18:07 ` [PATCH v4 12/12] arm64: enable generic CPU vulnerabilites support Jeremy Linton
2019-01-31 17:56 ` Andre Przywara
2019-02-08 20:05 ` [PATCH v4 00/12] arm64: add system vulnerability sysfs entries Stefan Wahren
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