linux-kernel - [PATCH 13/16] arm64: Add support for checking errata based on a list of MIDRS

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Message-Id: <20180123122809.16269-14-suzuki.poulose@arm.com>
Date:   Tue, 23 Jan 2018 12:28:06 +0000
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, ard.biesheuvel@...aro.org,
        will.deacon@....com, mark.rutland@....com, marc.zyngier@....com,
        catalin.marinas@....com, ckadabi@...eaurora.org,
        jnair@...iumnetworks.com, Suzuki K Poulose <suzuki.poulose@....com>
Subject: [PATCH 13/16] arm64: Add support for checking errata based on a list of MIDRS

Add helpers for detecting an errata on list of midr ranges
of affected CPUs.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>
---
 arch/arm64/include/asm/cpufeature.h |  1 +
 arch/arm64/kernel/cpu_errata.c      | 40 ++++++++++++++++++++++---------------
 2 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index a3d54c2c411f..70712de687c7 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -136,6 +136,7 @@ struct arm64_cpu_capabilities {
 	int (*enable)(const struct arm64_cpu_capabilities *caps);
 	union {
 		struct midr_range midr_range;	/* To be used for erratum handling only */
+		const struct midr_range *midr_range_list;
 		struct {	/* Feature register checking */
 			u32 sys_reg;
 			u8 field_pos;
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 10eb7fa0d0d7..8472d156c225 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -29,6 +29,13 @@ is_affected_midr_range(const struct arm64_cpu_capabilities *entry, int scope)
 }
 
 static bool __maybe_unused
+is_affected_midr_range_list(const struct arm64_cpu_capabilities *entry, int scope)
+{
+	WARN_ON(scope != SCOPE_LOCAL_CPU || preemptible());
+	return is_midr_in_range_list(read_cpuid_id(), entry->midr_range_list);
+}
+
+static bool __maybe_unused
 is_kryo_midr(const struct arm64_cpu_capabilities *entry, int scope)
 {
 	u32 model;
@@ -196,6 +203,22 @@ static int qcom_enable_link_stack_sanitization(
 	.matches = is_affected_midr_range, \
 	.midr_range = MIDR_ALL_VERSIONS(model)
 
+/* Errata affecting a list of midr ranges, with same work around */
+#define ERRATA_MIDR_RANGE_LIST(midr_list) \
+	.type = ARM64_CPUCAP_STRICT_CPU_LOCAL_ERRATUM, \
+	.matches = is_affected_midr_range_list, \
+	.midr_range_list = midr_list
+
+#ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
+static const struct midr_range cortex_bp_harden_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),
+	{},
+};
+#endif
+
 const struct arm64_cpu_capabilities arm64_errata[] = {
 #if	defined(CONFIG_ARM64_ERRATUM_826319) || \
 	defined(CONFIG_ARM64_ERRATUM_827319) || \
@@ -330,22 +353,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR
 	{
 		.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
-		ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
-		.enable = enable_psci_bp_hardening,
-	},
-	{
-		.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
-		ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
-		.enable = enable_psci_bp_hardening,
-	},
-	{
-		.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
-		ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
-		.enable = enable_psci_bp_hardening,
-	},
-	{
-		.capability = ARM64_HARDEN_BRANCH_PREDICTOR,
-		ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A75),
+		ERRATA_MIDR_RANGE_LIST(cortex_bp_harden_cpus),
 		.enable = enable_psci_bp_hardening,
 	},
 	{
-- 
2.13.6