* [v12 PATCH 1/2] EDAC: Add EDAC driver for ARM Cortex A72 cores
2025-07-17 1:06 [v12 PATCH 0/2] Add L1 and L2 error detection for A72 Vijay Balakrishna
@ 2025-07-17 1:06 ` Vijay Balakrishna
2025-07-17 1:06 ` [v12 PATCH 2/2] dt-bindings: arm: cpus: Add edac-enabled property Vijay Balakrishna
2025-08-15 21:39 ` [v12 PATCH 0/2] Add L1 and L2 error detection for A72 Borislav Petkov
2 siblings, 0 replies; 4+ messages in thread
From: Vijay Balakrishna @ 2025-07-17 1:06 UTC (permalink / raw)
To: Borislav Petkov, Tony Luck, Rob Herring, Krzysztof Kozlowski,
Conor Dooley
Cc: James Morse, Mauro Carvalho Chehab, Robert Richter, linux-edac,
linux-kernel, Tyler Hicks, Marc Zyngier, Sascha Hauer,
Lorenzo Pieralisi, devicetree, Vijay Balakrishna
From: Sascha Hauer <s.hauer@pengutronix.de>
The driver is designed to support error detection and reporting for
Cortex A72 cores, specifically within their L1 and L2 cache systems.
The errors are detected by reading CPU/L2 memory error syndrome
registers.
Unfortunately there is no robust way to inject errors into the caches,
so this driver doesn't contain any code to actually test it. It has
been tested though with code taken from an older version [1] of this
driver. For reasons stated in thread [1], the error injection code is
not suitable for mainline, so it is removed from the driver.
[1] https://lore.kernel.org/all/1521073067-24348-1-git-send-email-york.sun@nxp.com/#t
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Co-developed-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
---
MAINTAINERS | 7 ++
drivers/edac/Kconfig | 8 ++
drivers/edac/Makefile | 1 +
drivers/edac/a72_edac.c | 227 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 243 insertions(+)
create mode 100644 drivers/edac/a72_edac.c
diff --git a/MAINTAINERS b/MAINTAINERS
index c3f7fbd0d67a..d237ab92fdb0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8588,6 +8588,13 @@ F: Documentation/driver-api/edac.rst
F: drivers/edac/
F: include/linux/edac.h
+EDAC-A72
+M: Vijay Balakrishna <vijayb@linux.microsoft.com>
+M: Tyler Hicks <code@tyhicks.com>
+L: linux-edac@vger.kernel.org
+S: Supported
+F: drivers/edac/a72_edac.c
+
EDAC-DMC520
M: Lei Wang <lewan@microsoft.com>
L: linux-edac@vger.kernel.org
diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 19ad3c3b675d..b824472208c4 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -576,4 +576,12 @@ config EDAC_LOONGSON
errors (CE) only. Loongson-3A5000/3C5000/3D5000/3A6000/3C6000
are compatible.
+config EDAC_CORTEX_A72
+ tristate "ARM Cortex A72"
+ depends on ARM64
+ help
+ Support for L1/L2 cache error detection for ARM Cortex A72 processor.
+ The detected and reported errors are from reading CPU/L2 memory error
+ syndrome registers.
+
endif # EDAC
diff --git a/drivers/edac/Makefile b/drivers/edac/Makefile
index a8f2d8f6c894..c1736f264320 100644
--- a/drivers/edac/Makefile
+++ b/drivers/edac/Makefile
@@ -88,3 +88,4 @@ obj-$(CONFIG_EDAC_NPCM) += npcm_edac.o
obj-$(CONFIG_EDAC_ZYNQMP) += zynqmp_edac.o
obj-$(CONFIG_EDAC_VERSAL) += versal_edac.o
obj-$(CONFIG_EDAC_LOONGSON) += loongson_edac.o
+obj-$(CONFIG_EDAC_CORTEX_A72) += a72_edac.o
diff --git a/drivers/edac/a72_edac.c b/drivers/edac/a72_edac.c
new file mode 100644
index 000000000000..997dc9547637
--- /dev/null
+++ b/drivers/edac/a72_edac.c
@@ -0,0 +1,227 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Cortex A72 EDAC L1 and L2 cache error detection
+ *
+ * Copyright (c) 2020 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
+ * Copyright (c) 2025 Microsoft Corporation, <vijayb@linux.microsoft.com>
+ *
+ * Based on Code from:
+ * Copyright (c) 2018, NXP Semiconductor
+ * Author: York Sun <york.sun@nxp.com>
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/bitfield.h>
+#include <asm/smp_plat.h>
+
+#include "edac_module.h"
+
+#define DRVNAME "a72-edac"
+
+#define SYS_CPUMERRSR_EL1 sys_reg(3, 1, 15, 2, 2)
+#define SYS_L2MERRSR_EL1 sys_reg(3, 1, 15, 2, 3)
+
+#define CPUMERRSR_EL1_RAMID GENMASK(30, 24)
+#define L2MERRSR_EL1_CPUID_WAY GENMASK(21, 18)
+
+#define CPUMERRSR_EL1_VALID BIT(31)
+#define CPUMERRSR_EL1_FATAL BIT(63)
+#define L2MERRSR_EL1_VALID BIT(31)
+#define L2MERRSR_EL1_FATAL BIT(63)
+
+#define L1_I_TAG_RAM 0x00
+#define L1_I_DATA_RAM 0x01
+#define L1_D_TAG_RAM 0x08
+#define L1_D_DATA_RAM 0x09
+#define TLB_RAM 0x18
+
+#define MESSAGE_SIZE 64
+
+struct mem_err_synd_reg {
+ u64 cpu_mesr;
+ u64 l2_mesr;
+};
+
+static struct cpumask compat_mask;
+
+static void report_errors(struct edac_device_ctl_info *edac_ctl, int cpu,
+ struct mem_err_synd_reg *mesr)
+{
+ u64 cpu_mesr = mesr->cpu_mesr;
+ u64 l2_mesr = mesr->l2_mesr;
+ char msg[MESSAGE_SIZE];
+
+ if (cpu_mesr & CPUMERRSR_EL1_VALID) {
+ const char *str;
+ bool fatal = cpu_mesr & CPUMERRSR_EL1_FATAL;
+
+ switch (FIELD_GET(CPUMERRSR_EL1_RAMID, cpu_mesr)) {
+ case L1_I_TAG_RAM:
+ str = "L1-I Tag RAM";
+ break;
+ case L1_I_DATA_RAM:
+ str = "L1-I Data RAM";
+ break;
+ case L1_D_TAG_RAM:
+ str = "L1-D Tag RAM";
+ break;
+ case L1_D_DATA_RAM:
+ str = "L1-D Data RAM";
+ break;
+ case TLB_RAM:
+ str = "TLB RAM";
+ break;
+ default:
+ str = "Unspecified";
+ break;
+ }
+
+ snprintf(msg, MESSAGE_SIZE, "%s %s error(s) on CPU %d",
+ str, fatal ? "fatal" : "correctable", cpu);
+
+ if (fatal)
+ edac_device_handle_ue(edac_ctl, cpu, 0, msg);
+ else
+ edac_device_handle_ce(edac_ctl, cpu, 0, msg);
+ }
+
+ if (l2_mesr & L2MERRSR_EL1_VALID) {
+ bool fatal = l2_mesr & L2MERRSR_EL1_FATAL;
+
+ snprintf(msg, MESSAGE_SIZE, "L2 %s error(s) on CPU %d CPUID/WAY 0x%lx",
+ fatal ? "fatal" : "correctable", cpu,
+ FIELD_GET(L2MERRSR_EL1_CPUID_WAY, l2_mesr));
+ if (fatal)
+ edac_device_handle_ue(edac_ctl, cpu, 1, msg);
+ else
+ edac_device_handle_ce(edac_ctl, cpu, 1, msg);
+ }
+}
+
+static void read_errors(void *data)
+{
+ struct mem_err_synd_reg *mesr = data;
+
+ mesr->cpu_mesr = read_sysreg_s(SYS_CPUMERRSR_EL1);
+ if (mesr->cpu_mesr & CPUMERRSR_EL1_VALID) {
+ write_sysreg_s(0, SYS_CPUMERRSR_EL1);
+ isb();
+ }
+ mesr->l2_mesr = read_sysreg_s(SYS_L2MERRSR_EL1);
+ if (mesr->l2_mesr & L2MERRSR_EL1_VALID) {
+ write_sysreg_s(0, SYS_L2MERRSR_EL1);
+ isb();
+ }
+}
+
+static void a72_edac_check(struct edac_device_ctl_info *edac_ctl)
+{
+ struct mem_err_synd_reg mesr;
+ int cpu;
+
+ cpus_read_lock();
+ for_each_cpu_and(cpu, cpu_online_mask, &compat_mask) {
+ smp_call_function_single(cpu, read_errors, &mesr, true);
+ report_errors(edac_ctl, cpu, &mesr);
+ }
+ cpus_read_unlock();
+}
+
+static int a72_edac_probe(struct platform_device *pdev)
+{
+ struct edac_device_ctl_info *edac_ctl;
+ struct device *dev = &pdev->dev;
+ int rc;
+
+ edac_ctl = edac_device_alloc_ctl_info(0, "cpu",
+ num_possible_cpus(), "L", 2, 1,
+ edac_device_alloc_index());
+ if (!edac_ctl)
+ return -ENOMEM;
+
+ edac_ctl->edac_check = a72_edac_check;
+ edac_ctl->dev = dev;
+ edac_ctl->mod_name = dev_name(dev);
+ edac_ctl->dev_name = dev_name(dev);
+ edac_ctl->ctl_name = DRVNAME;
+ dev_set_drvdata(dev, edac_ctl);
+
+ rc = edac_device_add_device(edac_ctl);
+ if (rc)
+ goto out_dev;
+
+ return 0;
+
+out_dev:
+ edac_device_free_ctl_info(edac_ctl);
+
+ return rc;
+}
+
+static void a72_edac_remove(struct platform_device *pdev)
+{
+ struct edac_device_ctl_info *edac_ctl = dev_get_drvdata(&pdev->dev);
+
+ edac_device_del_device(edac_ctl->dev);
+ edac_device_free_ctl_info(edac_ctl);
+}
+
+static const struct of_device_id cortex_arm64_edac_of_match[] = {
+ { .compatible = "arm,cortex-a72" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, cortex_arm64_edac_of_match);
+
+static struct platform_driver a72_edac_driver = {
+ .probe = a72_edac_probe,
+ .remove = a72_edac_remove,
+ .driver = {
+ .name = DRVNAME,
+ },
+};
+
+static struct platform_device *a72_pdev;
+
+static int __init a72_edac_driver_init(void)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct device_node *np __free(device_node) =
+ of_cpu_device_node_get(cpu);
+
+ if (np) {
+ if (of_match_node(cortex_arm64_edac_of_match, np) &&
+ of_property_read_bool(np, "edac-enabled")) {
+ cpumask_set_cpu(cpu, &compat_mask);
+ }
+ } else {
+ pr_warn("failed to find device node for CPU %d\n", cpu);
+ }
+ }
+
+ if (cpumask_empty(&compat_mask))
+ return 0;
+
+ a72_pdev = platform_device_register_simple(DRVNAME, -1, NULL, 0);
+ if (IS_ERR(a72_pdev)) {
+ pr_err("failed to register a72 edac device\n");
+ return PTR_ERR(a72_pdev);
+ }
+
+ return platform_driver_register(&a72_edac_driver);
+}
+
+static void __exit a72_edac_driver_exit(void)
+{
+ platform_device_unregister(a72_pdev);
+ platform_driver_unregister(&a72_edac_driver);
+}
+
+module_init(a72_edac_driver_init);
+module_exit(a72_edac_driver_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
+MODULE_DESCRIPTION("Cortex A72 L1 and L2 cache EDAC driver");
--
2.49.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [v12 PATCH 2/2] dt-bindings: arm: cpus: Add edac-enabled property
2025-07-17 1:06 [v12 PATCH 0/2] Add L1 and L2 error detection for A72 Vijay Balakrishna
2025-07-17 1:06 ` [v12 PATCH 1/2] EDAC: Add EDAC driver for ARM Cortex A72 cores Vijay Balakrishna
@ 2025-07-17 1:06 ` Vijay Balakrishna
2025-08-15 21:39 ` [v12 PATCH 0/2] Add L1 and L2 error detection for A72 Borislav Petkov
2 siblings, 0 replies; 4+ messages in thread
From: Vijay Balakrishna @ 2025-07-17 1:06 UTC (permalink / raw)
To: Borislav Petkov, Tony Luck, Rob Herring, Krzysztof Kozlowski,
Conor Dooley
Cc: James Morse, Mauro Carvalho Chehab, Robert Richter, linux-edac,
linux-kernel, Tyler Hicks, Marc Zyngier, Sascha Hauer,
Lorenzo Pieralisi, devicetree, Vijay Balakrishna
From: Sascha Hauer <s.hauer@pengutronix.de>
Some ARM Cortex CPUs including A72 have Error Detection And
Correction (EDAC) support on their L1 and L2 caches. This is implemented
in implementation defined registers, so usage of this functionality is
not safe in virtualized environments or when EL3 already uses these
registers. This patch adds a edac-enabled flag which can be explicitly
set when EDAC can be used.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
[vijayb: Added A72 to the commit message]
Signed-off-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
Documentation/devicetree/bindings/arm/cpus.yaml | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/Documentation/devicetree/bindings/arm/cpus.yaml b/Documentation/devicetree/bindings/arm/cpus.yaml
index 2e9ab9583005..67eaa6df5959 100644
--- a/Documentation/devicetree/bindings/arm/cpus.yaml
+++ b/Documentation/devicetree/bindings/arm/cpus.yaml
@@ -352,6 +352,12 @@ properties:
$ref: /schemas/types.yaml#/definitions/phandle
description: Link to Mediatek Cache Coherent Interconnect
+ edac-enabled:
+ $ref: /schemas/types.yaml#/definitions/flag
+ description:
+ A72 CPUs support Error Detection And Correction (EDAC) on their L1 and
+ L2 caches. This flag marks this function as usable.
+
qcom,saw:
$ref: /schemas/types.yaml#/definitions/phandle
description:
@@ -398,6 +404,17 @@ properties:
allOf:
- $ref: /schemas/cpu.yaml#
- $ref: /schemas/opp/opp-v1.yaml#
+ - if:
+ not:
+ properties:
+ compatible:
+ contains:
+ const: arm,cortex-a72
+ then:
+ # Allow edac-enabled only for Cortex A72
+ properties:
+ edac-enabled: false
+
- if:
# If the enable-method property contains one of those values
properties:
--
2.49.0
^ permalink raw reply related [flat|nested] 4+ messages in thread