From: Linu Cherian <lcherian@marvell.com>

Date: Mon, 7 Mar 2022 20:00:14 +0530

Subject: irqchip/gic-v3: Workaround Marvell erratum 38545 when reading IAR

Git-commit: 24a147bcef8ca039cb75d6d4b68c7cc339b11178

Patch-mainline: v5.18-rc1

References: jsc#SLE-24682

When a IAR register read races with a GIC interrupt RELEASE event,

GIC-CPU interface could wrongly return a valid INTID to the CPU

for an interrupt that is already released(non activated) instead of 0x3ff.

As a side effect, an interrupt handler could run twice, once with

interrupt priority and then with idle priority.

As a workaround, gic_read_iar is updated so that it will return a

valid interrupt ID only if there is a change in the active priority list

after the IAR read on all the affected Silicons.

Since there are silicon variants where both 23154 and 38545 are applicable,

workaround for erratum 23154 has been extended to address both of them.

Signed-off-by: Linu Cherian <lcherian@marvell.com>

Reviewed-by: Marc Zyngier <maz@kernel.org>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

Link: https://lore.kernel.org/r/20220307143014.22758-1-lcherian@marvell.com

Signed-off-by: Will Deacon <will@kernel.org>

Signed-off-by: Matthias Brugger <mbrugger@suse.com>

---

 Documentation/arm64/silicon-errata.rst |  2 +-

 arch/arm64/Kconfig                     |  8 ++++++--

 arch/arm64/include/asm/arch_gicv3.h    | 23 +++++++++++++++++++++--

 arch/arm64/include/asm/cputype.h       | 13 +++++++++++++

 arch/arm64/kernel/cpu_errata.c         | 20 +++++++++++++++++---

 5 files changed, 58 insertions(+), 8 deletions(-)

diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/silicon-errata.rst

index ea281dd75517..466cb9e89047 100644

--- a/Documentation/arm64/silicon-errata.rst

+++ b/Documentation/arm64/silicon-errata.rst

@@ -136,7 +136,7 @@ stable kernels.

 +----------------+-----------------+-----------------+-----------------------------+

 | Cavium         | ThunderX ITS    | #23144          | CAVIUM_ERRATUM_23144        |

 +----------------+-----------------+-----------------+-----------------------------+

-| Cavium         | ThunderX GICv3  | #23154          | CAVIUM_ERRATUM_23154        |

+| Cavium         | ThunderX GICv3  | #23154,38545    | CAVIUM_ERRATUM_23154        |

 +----------------+-----------------+-----------------+-----------------------------+

 | Cavium         | ThunderX GICv3  | #38539          | N/A                         |

 +----------------+-----------------+-----------------+-----------------------------+

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig

index cbcd42decb2a..b154aa98c43a 100644

--- a/arch/arm64/Kconfig

+++ b/arch/arm64/Kconfig

@@ -890,13 +890,17 @@ config CAVIUM_ERRATUM_23144

 	  If unsure, say Y.

 config CAVIUM_ERRATUM_23154

-	bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"

+	bool "Cavium errata 23154 and 38545: GICv3 lacks HW synchronisation"

 	default y

 	help

-	  The gicv3 of ThunderX requires a modified version for

+	  The ThunderX GICv3 implementation requires a modified version for

 	  reading the IAR status to ensure data synchronization

 	  (access to icc_iar1_el1 is not sync'ed before and after).

+	  It also suffers from erratum 38545 (also present on Marvell's

+	  OcteonTX and OcteonTX2), resulting in deactivated interrupts being

+	  spuriously presented to the CPU interface.

+

 	  If unsure, say Y.

 config CAVIUM_ERRATUM_27456

diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h

index 4ad22c3135db..8bd5afc7b692 100644

--- a/arch/arm64/include/asm/arch_gicv3.h

+++ b/arch/arm64/include/asm/arch_gicv3.h

@@ -53,17 +53,36 @@ static inline u64 gic_read_iar_common(void)

  * The gicv3 of ThunderX requires a modified version for reading the

  * IAR status to ensure data synchronization (access to icc_iar1_el1

  * is not sync'ed before and after).

+ *

+ * Erratum 38545

+ *

+ * When a IAR register read races with a GIC interrupt RELEASE event,

+ * GIC-CPU interface could wrongly return a valid INTID to the CPU

+ * for an interrupt that is already released(non activated) instead of 0x3ff.

+ *

+ * To workaround this, return a valid interrupt ID only if there is a change

+ * in the active priority list after the IAR read.

+ *

+ * Common function used for both the workarounds since,

+ * 1. On Thunderx 88xx 1.x both erratas are applicable.

+ * 2. Having extra nops doesn't add any side effects for Silicons where

+ *    erratum 23154 is not applicable.

  */

 static inline u64 gic_read_iar_cavium_thunderx(void)

 {

-	u64 irqstat;

+	u64 irqstat, apr;

+	apr = read_sysreg_s(SYS_ICC_AP1R0_EL1);

 	nops(8);

 	irqstat = read_sysreg_s(SYS_ICC_IAR1_EL1);

 	nops(4);

 	mb();

-	return irqstat;

+	/* Max priority groups implemented is only 32 */

+	if (likely(apr != read_sysreg_s(SYS_ICC_AP1R0_EL1)))

+		return irqstat;

+

+	return 0x3ff;

 }

 static inline void gic_write_ctlr(u32 val)

diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h

index 999b9149f856..4596e7ca29a3 100644

--- a/arch/arm64/include/asm/cputype.h

+++ b/arch/arm64/include/asm/cputype.h

@@ -84,6 +84,13 @@

 #define CAVIUM_CPU_PART_THUNDERX_81XX	0x0A2

 #define CAVIUM_CPU_PART_THUNDERX_83XX	0x0A3

 #define CAVIUM_CPU_PART_THUNDERX2	0x0AF

+/* OcteonTx2 series */

+#define CAVIUM_CPU_PART_OCTX2_98XX	0x0B1

+#define CAVIUM_CPU_PART_OCTX2_96XX	0x0B2

+#define CAVIUM_CPU_PART_OCTX2_95XX	0x0B3

+#define CAVIUM_CPU_PART_OCTX2_95XXN	0x0B4

+#define CAVIUM_CPU_PART_OCTX2_95XXMM	0x0B5

+#define CAVIUM_CPU_PART_OCTX2_95XXO	0x0B6

 #define BRCM_CPU_PART_BRAHMA_B53	0x100

 #define BRCM_CPU_PART_VULCAN		0x516

@@ -124,6 +131,12 @@

 #define MIDR_THUNDERX	MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX)

 #define MIDR_THUNDERX_81XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX_81XX)

 #define MIDR_THUNDERX_83XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX_83XX)

+#define MIDR_OCTX2_98XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_OCTX2_98XX)

+#define MIDR_OCTX2_96XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_OCTX2_96XX)

+#define MIDR_OCTX2_95XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_OCTX2_95XX)

+#define MIDR_OCTX2_95XXN MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_OCTX2_95XXN)

+#define MIDR_OCTX2_95XXMM MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_OCTX2_95XXMM)

+#define MIDR_OCTX2_95XXO MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_OCTX2_95XXO)

 #define MIDR_CAVIUM_THUNDERX2 MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX2)

 #define MIDR_BRAHMA_B53 MIDR_CPU_MODEL(ARM_CPU_IMP_BRCM, BRCM_CPU_PART_BRAHMA_B53)

 #define MIDR_BRCM_VULCAN MIDR_CPU_MODEL(ARM_CPU_IMP_BRCM, BRCM_CPU_PART_VULCAN)

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c

index b217941713a8..510f47055b91 100644

--- a/arch/arm64/kernel/cpu_errata.c

+++ b/arch/arm64/kernel/cpu_errata.c

@@ -214,6 +214,20 @@ static const struct arm64_cpu_capabilities arm64_repeat_tlbi_list[] = {

 };

 #endif

+#ifdef CONFIG_CAVIUM_ERRATUM_23154

+const struct midr_range cavium_erratum_23154_cpus[] = {

+	MIDR_ALL_VERSIONS(MIDR_THUNDERX),

+	MIDR_ALL_VERSIONS(MIDR_THUNDERX_81XX),

+	MIDR_ALL_VERSIONS(MIDR_THUNDERX_83XX),

+	MIDR_ALL_VERSIONS(MIDR_OCTX2_98XX),

+	MIDR_ALL_VERSIONS(MIDR_OCTX2_96XX),

+	MIDR_ALL_VERSIONS(MIDR_OCTX2_95XX),

+	MIDR_ALL_VERSIONS(MIDR_OCTX2_95XXN),

+	MIDR_ALL_VERSIONS(MIDR_OCTX2_95XXMM),

+	MIDR_ALL_VERSIONS(MIDR_OCTX2_95XXO),

+};

+#endif

+

 #ifdef CONFIG_CAVIUM_ERRATUM_27456

 const struct midr_range cavium_erratum_27456_cpus[] = {

 	/* Cavium ThunderX, T88 pass 1.x - 2.1 */

@@ -425,10 +439,10 @@ const struct arm64_cpu_capabilities arm64_errata[] = {

 #endif

 #ifdef CONFIG_CAVIUM_ERRATUM_23154

 	{

-	/* Cavium ThunderX, pass 1.x */

-		.desc = "Cavium erratum 23154",

+		.desc = "Cavium errata 23154 and 38545",

 		.capability = ARM64_WORKAROUND_CAVIUM_23154,

-		ERRATA_MIDR_REV_RANGE(MIDR_THUNDERX, 0, 0, 1),

+		.type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,

+		ERRATA_MIDR_RANGE_LIST(cavium_erratum_23154_cpus),

 	},

 #endif

 #ifdef CONFIG_CAVIUM_ERRATUM_27456

-- 

2.36.0