[v4.4,V2,16/43] arm64: Verify CPU errata work arounds on hotplugged CPU

Message ID 69ba9cb57c88ef7c15651a3f474a209dabe9d89b.1562908075.git.viresh.kumar@linaro.org
State New
Headers show
Series
  • V4.4 backport of arm64 Spectre patches
Related show

Commit Message

Viresh Kumar July 12, 2019, 5:28 a.m.
From: Suzuki K Poulose <suzuki.poulose@arm.com>


commit 6a6efbb45b7d95c84840010095367eb06a64f342 upstream.

CPU Errata work arounds are detected and applied to the
kernel code at boot time and the data is then freed up.
If a new hotplugged CPU requires a work around which
was not applied at boot time, there is nothing we can
do but simply fail the booting.

Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Signed-off-by: Will Deacon <will.deacon@arm.com>

[ Viresh: Resolved rebase conflict ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

---
 arch/arm64/include/asm/cpufeature.h |  2 ++
 arch/arm64/kernel/cpu_errata.c      | 20 ++++++++++++++++++++
 arch/arm64/kernel/cpufeature.c      |  2 ++
 3 files changed, 24 insertions(+)

-- 
2.21.0.rc0.269.g1a574e7a288b

Patch

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 4c31e14c0f0e..dd1aab8e52aa 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -173,6 +173,8 @@  void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
 			    const char *info);
 void check_local_cpu_errata(void);
 
+void verify_local_cpu_errata(void);
+
 #ifdef CONFIG_HOTPLUG_CPU
 void verify_local_cpu_capabilities(void);
 #else
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 0971d80d3623..a3567881c01b 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -116,6 +116,26 @@  const struct arm64_cpu_capabilities arm64_errata[] = {
 	}
 };
 
+/*
+ * The CPU Errata work arounds are detected and applied at boot time
+ * and the related information is freed soon after. If the new CPU requires
+ * an errata not detected at boot, fail this CPU.
+ */
+void verify_local_cpu_errata(void)
+{
+	const struct arm64_cpu_capabilities *caps = arm64_errata;
+
+	for (; caps->matches; caps++)
+		if (!cpus_have_cap(caps->capability) &&
+			caps->matches(caps, SCOPE_LOCAL_CPU)) {
+			pr_crit("CPU%d: Requires work around for %s, not detected"
+					" at boot time\n",
+				smp_processor_id(),
+				caps->desc ? : "an erratum");
+			cpu_die_early();
+		}
+}
+
 void check_local_cpu_errata(void)
 {
 	update_cpu_capabilities(arm64_errata, "enabling workaround for");
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index a0273cd8be51..9a4b638b1c18 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -872,6 +872,8 @@  void verify_local_cpu_capabilities(void)
 	if (!sys_caps_initialised)
 		return;
 
+	verify_local_cpu_errata();
+
 	caps = arm64_features;
 	for (i = 0; caps[i].matches; i++) {
 		if (!cpus_have_cap(caps[i].capability) || !caps[i].sys_reg)