[PATCH v5 0/8] Make ghes_edac a proper module

[PATCH v5 0/8] Make ghes_edac a proper module

[Jia He]

Commit dc4e8c07e9e2 ("ACPI: APEI: explicit init of HEST and GHES in
apci_init()") introduced a bug that ghes_edac_register() would be invoked
before edac_init(). Because at that time, the bus "edac" hasn't been even
registered, this created sysfs /devices/mc0 instead of
/sys/devices/system/edac/mc/mc0 on an Ampere eMag server.

The proper solution is to make ghes_edac a proper module.

Changelog:
v5:
 - add the review-by from Toshi for patch 04 and 06
 - refine the commit msg
 - remove the unconditional set of ghes_edac_force_enable on Arm
v4: https://lore.kernel.org/lkml/20220831074027.13849-6-justin.he@arm.com/
 - move the kernel boot option to ghes module parameter
 - collapse th ghes_present and ghes_edac_preferred into one patch
v3: https://lore.kernel.org/lkml/20220822154048.188253-1-justin.he@arm.com/
 - refine the commit logs
 - introduce ghes preferred and present flag (by Toshi)
 - move force_load to setup parameter
 - add the ghes_edac_preferred() check for x86/Arm edac drivers
v2: https://lore.kernel.org/lkml/20220817143458.335938-1-justin.he@arm.com/
 - add acked-by tag of Patch 1 from Ard
 - split the notifier patch
 - add 2 patch to get regular drivers selected when ghes edac is not loaded
 - fix an errno in igen6 driver
 - add a patch to fix the sparse warning of ghes
 - refine the commit logs
v1: https://lore.kernel.org/lkml/20220811091713.10427-1-justin.he@arm.com/

Jia He (8):
  efi/cper: export several helpers for ghes_edac to use
  EDAC/ghes: Add a notifier for reporting memory errors
  EDAC:ghes: Move ghes_edac.force_load to ghes module parameter
  ghes: Introduce a helper ghes_edac_preferred()
  EDAC/ghes: Make ghes_edac a proper module to remove the dependency on
    ghes
  EDAC: Add the ghes_edac_preferred check for chipset-specific edac
    drivers
  apei/ghes: Use unrcu_pointer for cmpxchg
  EDAC/igen6: Return consistent errno when another edac driver is
    enabled

 drivers/acpi/apei/ghes.c       | 82 +++++++++++++++++++++++++++++++---
 drivers/edac/Kconfig           |  4 +-
 drivers/edac/amd64_edac.c      |  3 ++
 drivers/edac/armada_xp_edac.c  |  3 ++
 drivers/edac/edac_module.h     |  1 +
 drivers/edac/ghes_edac.c       | 78 ++++++++++++++++++++------------
 drivers/edac/i10nm_base.c      |  3 ++
 drivers/edac/igen6_edac.c      |  5 ++-
 drivers/edac/layerscape_edac.c |  3 ++
 drivers/edac/pnd2_edac.c       |  3 ++
 drivers/edac/sb_edac.c         |  3 ++
 drivers/edac/skx_base.c        |  3 ++
 drivers/edac/thunderx_edac.c   |  3 ++
 drivers/edac/xgene_edac.c      |  3 ++
 drivers/firmware/efi/cper.c    |  3 ++
 include/acpi/apei.h            |  2 +
 include/acpi/ghes.h            | 36 +++++----------
 17 files changed, 175 insertions(+), 63 deletions(-)

-- 
2.25.1

[PATCH v5 1/8] efi/cper: export several helpers for ghes_edac to use

[Jia He]

Before ghes_edac can be turned back into a proper module again, export
several helpers which are going to be used by it.

Signed-off-by: Jia He <justin.he@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/cper.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index e4e5ea7ce910..053eae13f409 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -290,6 +290,7 @@ int cper_mem_err_location(struct cper_mem_err_compact *mem, char *msg)
 
 	return n;
 }
+EXPORT_SYMBOL_GPL(cper_mem_err_location);
 
 int cper_dimm_err_location(struct cper_mem_err_compact *mem, char *msg)
 {
@@ -310,6 +311,7 @@ int cper_dimm_err_location(struct cper_mem_err_compact *mem, char *msg)
 
 	return n;
 }
+EXPORT_SYMBOL_GPL(cper_dimm_err_location);
 
 void cper_mem_err_pack(const struct cper_sec_mem_err *mem,
 		       struct cper_mem_err_compact *cmem)
@@ -331,6 +333,7 @@ void cper_mem_err_pack(const struct cper_sec_mem_err *mem,
 	cmem->mem_array_handle = mem->mem_array_handle;
 	cmem->mem_dev_handle = mem->mem_dev_handle;
 }
+EXPORT_SYMBOL_GPL(cper_mem_err_pack);
 
 const char *cper_mem_err_unpack(struct trace_seq *p,
 				struct cper_mem_err_compact *cmem)
-- 
2.25.1

[PATCH v5 2/8] EDAC/ghes: Add a notifier for reporting memory errors

[Jia He]

To make a proper module, add a notifier for reporting memory errors. Use
an atomic notifier because calls sites like ghes_proc_in_irq() run in
interrupt context.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jia He <justin.he@arm.com>
---
 drivers/acpi/apei/ghes.c | 16 +++++++++++++++-
 drivers/edac/ghes_edac.c | 19 +++++++++++++++++--
 include/acpi/ghes.h      | 10 +++-------
 3 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index d91ad378c00d..8cb65f757d06 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -94,6 +94,8 @@
 #define FIX_APEI_GHES_SDEI_CRITICAL	__end_of_fixed_addresses
 #endif
 
+static ATOMIC_NOTIFIER_HEAD(ghes_report_chain);
+
 static inline bool is_hest_type_generic_v2(struct ghes *ghes)
 {
 	return ghes->generic->header.type == ACPI_HEST_TYPE_GENERIC_ERROR_V2;
@@ -645,7 +647,7 @@ static bool ghes_do_proc(struct ghes *ghes,
 		if (guid_equal(sec_type, &CPER_SEC_PLATFORM_MEM)) {
 			struct cper_sec_mem_err *mem_err = acpi_hest_get_payload(gdata);
 
-			ghes_edac_report_mem_error(sev, mem_err);
+			atomic_notifier_call_chain(&ghes_report_chain, sev, mem_err);
 
 			arch_apei_report_mem_error(sev, mem_err);
 			queued = ghes_handle_memory_failure(gdata, sev);
@@ -1497,3 +1499,15 @@ void __init acpi_ghes_init(void)
 	else
 		pr_info(GHES_PFX "Failed to enable APEI firmware first mode.\n");
 }
+
+void ghes_register_report_chain(struct notifier_block *nb)
+{
+	atomic_notifier_chain_register(&ghes_report_chain, nb);
+}
+EXPORT_SYMBOL_GPL(ghes_register_report_chain);
+
+void ghes_unregister_report_chain(struct notifier_block *nb)
+{
+	atomic_notifier_chain_unregister(&ghes_report_chain, nb);
+}
+EXPORT_SYMBOL_GPL(ghes_unregister_report_chain);
diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index c8fa7dcfdbd0..7b8d56a769f6 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -14,6 +14,7 @@
 #include <linux/dmi.h>
 #include "edac_module.h"
 #include <ras/ras_event.h>
+#include <linux/notifier.h>
 
 #define OTHER_DETAIL_LEN	400
 
@@ -267,11 +268,14 @@ static int print_mem_error_other_detail(const struct cper_sec_mem_err *mem, char
 	return n;
 }
 
-void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err)
+static int ghes_edac_report_mem_error(struct notifier_block *nb,
+				      unsigned long val, void *data)
 {
+	struct cper_sec_mem_err *mem_err = (struct cper_sec_mem_err *)data;
 	struct cper_mem_err_compact cmem;
 	struct edac_raw_error_desc *e;
 	struct mem_ctl_info *mci;
+	unsigned long sev = val;
 	struct ghes_pvt *pvt;
 	unsigned long flags;
 	char *p;
@@ -282,7 +286,7 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err)
 	 * know.
 	 */
 	if (WARN_ON_ONCE(in_nmi()))
-		return;
+		return NOTIFY_OK;
 
 	spin_lock_irqsave(&ghes_lock, flags);
 
@@ -374,8 +378,15 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err)
 
 unlock:
 	spin_unlock_irqrestore(&ghes_lock, flags);
+
+	return NOTIFY_OK;
 }
 
+static struct notifier_block ghes_edac_mem_err_nb = {
+	.notifier_call	= ghes_edac_report_mem_error,
+	.priority	= 0,
+};
+
 /*
  * Known systems that are safe to enable this module.
  */
@@ -503,6 +514,8 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 	ghes_pvt = pvt;
 	spin_unlock_irqrestore(&ghes_lock, flags);
 
+	ghes_register_report_chain(&ghes_edac_mem_err_nb);
+
 	/* only set on success */
 	refcount_set(&ghes_refcount, 1);
 
@@ -548,6 +561,8 @@ void ghes_edac_unregister(struct ghes *ghes)
 	if (mci)
 		edac_mc_free(mci);
 
+	ghes_unregister_report_chain(&ghes_edac_mem_err_nb);
+
 unlock:
 	mutex_unlock(&ghes_reg_mutex);
 }
diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
index 34fb3431a8f3..5cbd38b6e4e1 100644
--- a/include/acpi/ghes.h
+++ b/include/acpi/ghes.h
@@ -76,18 +76,11 @@ int ghes_estatus_pool_init(int num_ghes);
 /* From drivers/edac/ghes_edac.c */
 
 #ifdef CONFIG_EDAC_GHES
-void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err);
-
 int ghes_edac_register(struct ghes *ghes, struct device *dev);
 
 void ghes_edac_unregister(struct ghes *ghes);
 
 #else
-static inline void ghes_edac_report_mem_error(int sev,
-				       struct cper_sec_mem_err *mem_err)
-{
-}
-
 static inline int ghes_edac_register(struct ghes *ghes, struct device *dev)
 {
 	return -ENODEV;
@@ -145,4 +138,7 @@ int ghes_notify_sea(void);
 static inline int ghes_notify_sea(void) { return -ENOENT; }
 #endif
 
+struct notifier_block;
+extern void ghes_register_report_chain(struct notifier_block *nb);
+extern void ghes_unregister_report_chain(struct notifier_block *nb);
 #endif /* GHES_H */
-- 
2.25.1

[PATCH v5 3/8] EDAC:ghes: Move ghes_edac.force_load to ghes module parameter

[Jia He]

ghes_edac_init() is too late to set this module flag ghes_edac.force_load.
Also, other edac drivers should not be able to control this flag.

Move this flag to the module parameter in ghes instead.

Suggested-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Jia He <justin.he@arm.com>
---
 drivers/acpi/apei/ghes.c |  8 ++++++++
 drivers/edac/ghes_edac.c | 10 +++-------
 include/acpi/apei.h      |  2 ++
 3 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 8cb65f757d06..b0a6445c6da2 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -109,6 +109,14 @@ static inline bool is_hest_type_generic_v2(struct ghes *ghes)
 bool ghes_disable;
 module_param_named(disable, ghes_disable, bool, 0);
 
+/*
+ * "ghes.edac_force_enable" forcibly enables ghes_edac and skips the platform
+ * check.
+ */
+bool ghes_edac_force_enable;
+EXPORT_SYMBOL(ghes_edac_force_enable);
+module_param_named(edac_force_enable, ghes_edac_force_enable, bool, 0);
+
 /*
  * All error sources notified with HED (Hardware Error Device) share a
  * single notifier callback, so they need to be linked and checked one
diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index 7b8d56a769f6..11a1b5e7e484 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -54,10 +54,6 @@ static DEFINE_MUTEX(ghes_reg_mutex);
  */
 static DEFINE_SPINLOCK(ghes_lock);
 
-/* "ghes_edac.force_load=1" skips the platform check */
-static bool __read_mostly force_load;
-module_param(force_load, bool, 0);
-
 static bool system_scanned;
 
 /* Memory Device - Type 17 of SMBIOS spec */
@@ -408,10 +404,10 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 	if (IS_ENABLED(CONFIG_X86)) {
 		/* Check if safe to enable on this system */
 		idx = acpi_match_platform_list(plat_list);
-		if (!force_load && idx < 0)
+		if (!ghes_edac_force_enable && idx < 0)
 			return -ENODEV;
 	} else {
-		force_load = true;
+		ghes_edac_force_enable = true;
 		idx = 0;
 	}
 
@@ -535,7 +531,7 @@ void ghes_edac_unregister(struct ghes *ghes)
 	struct mem_ctl_info *mci;
 	unsigned long flags;
 
-	if (!force_load)
+	if (!ghes_edac_force_enable)
 		return;
 
 	mutex_lock(&ghes_reg_mutex);
diff --git a/include/acpi/apei.h b/include/acpi/apei.h
index dc60f7db5524..ab310393766e 100644
--- a/include/acpi/apei.h
+++ b/include/acpi/apei.h
@@ -27,9 +27,11 @@ extern int hest_disable;
 extern int erst_disable;
 #ifdef CONFIG_ACPI_APEI_GHES
 extern bool ghes_disable;
+extern bool ghes_edac_force_enable;
 void __init acpi_ghes_init(void);
 #else
 #define ghes_disable 1
+#define ghes_edac_force_enable 0
 static inline void acpi_ghes_init(void) { }
 #endif
 
-- 
2.25.1

[PATCH v5 4/8] ghes: Introduce a helper ghes_edac_preferred()

[Jia He]

Introduce a helper ghes_edac_preferred(), which returns true when ACPI GHES
table is present and the platform-check passes on the system. ghes_present
is set once in ghes_probe() since ACPI GHES table is static.

Suggested-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Jia He <justin.he@arm.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
---
 drivers/acpi/apei/ghes.c | 29 +++++++++++++++++++++++++++++
 include/acpi/ghes.h      |  2 ++
 2 files changed, 31 insertions(+)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index b0a6445c6da2..0c2dbfffe22a 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -117,6 +117,8 @@ bool ghes_edac_force_enable;
 EXPORT_SYMBOL(ghes_edac_force_enable);
 module_param_named(edac_force_enable, ghes_edac_force_enable, bool, 0);
 
+static bool ghes_present;
+
 /*
  * All error sources notified with HED (Hardware Error Device) share a
  * single notifier callback, so they need to be linked and checked one
@@ -1388,6 +1390,8 @@ static int ghes_probe(struct platform_device *ghes_dev)
 
 	ghes_edac_register(ghes, &ghes_dev->dev);
 
+	ghes_present = true;
+
 	/* Handle any pending errors right away */
 	spin_lock_irqsave(&ghes_notify_lock_irq, flags);
 	ghes_proc(ghes);
@@ -1508,6 +1512,31 @@ void __init acpi_ghes_init(void)
 		pr_info(GHES_PFX "Failed to enable APEI firmware first mode.\n");
 }
 
+/*
+ * Known x86 systems that prefer GHES error reporting:
+ */
+static struct acpi_platform_list plat_list[] = {
+	{"HPE   ", "Server  ", 0, ACPI_SIG_FADT, all_versions},
+	{ } /* End */
+};
+
+bool ghes_edac_preferred(void)
+{
+	int idx = -1;
+
+	if (!ghes_present)
+		return false;
+
+	if (IS_ENABLED(CONFIG_X86)) {
+		idx = acpi_match_platform_list(plat_list);
+		if (idx < 0 && !ghes_edac_force_enable)
+			return false;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(ghes_edac_preferred);
+
 void ghes_register_report_chain(struct notifier_block *nb)
 {
 	atomic_notifier_chain_register(&ghes_report_chain, nb);
diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
index 5cbd38b6e4e1..7ce91c0ff3eb 100644
--- a/include/acpi/ghes.h
+++ b/include/acpi/ghes.h
@@ -80,6 +80,7 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev);
 
 void ghes_edac_unregister(struct ghes *ghes);
 
+bool ghes_edac_preferred(void);
 #else
 static inline int ghes_edac_register(struct ghes *ghes, struct device *dev)
 {
@@ -89,6 +90,7 @@ static inline int ghes_edac_register(struct ghes *ghes, struct device *dev)
 static inline void ghes_edac_unregister(struct ghes *ghes)
 {
 }
+static bool ghes_edac_preferred(void) { return false; }
 #endif
 
 static inline int acpi_hest_get_version(struct acpi_hest_generic_data *gdata)
-- 
2.25.1

[PATCH v5 5/8] EDAC/ghes: Make ghes_edac a proper module to remove the dependency on ghes

[Jia He]

Commit dc4e8c07e9e2 ("ACPI: APEI: explicit init of HEST and GHES in
apci_init()") introduced a bug that ghes_edac_register() would be invoked
before edac_init(). Because at that time, the bus "edac" hadn't been even
registered, this created sysfs /devices/mc0 instead of
/sys/devices/system/edac/mc/mc0 on an Ampere eMag server.

To remove the dependency of ghes_edac on ghes, make it a proper module. Use
a list to save the probing devices in ghes_probe(), and defer the
ghes_edac_register() to module_init() of the new ghes_edac module by
iterating over the devices list.

Co-developed-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jia He <justin.he@arm.com>
Fixes: dc4e8c07e9e2 ("ACPI: APEI: explicit init of HEST and GHES in apci_init()")
Cc: Shuai Xue <xueshuai@linux.alibaba.com>
---
 drivers/acpi/apei/ghes.c | 22 +++++++++++++--
 drivers/edac/Kconfig     |  4 +--
 drivers/edac/ghes_edac.c | 59 +++++++++++++++++++++++-----------------
 include/acpi/ghes.h      | 24 ++++------------
 4 files changed, 62 insertions(+), 47 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 0c2dbfffe22a..4af269b22bd4 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -130,6 +130,9 @@ static bool ghes_present;
 static LIST_HEAD(ghes_hed);
 static DEFINE_MUTEX(ghes_list_mutex);
 
+static LIST_HEAD(ghes_devs);
+static DEFINE_MUTEX(ghes_devs_mutex);
+
 /*
  * Because the memory area used to transfer hardware error information
  * from BIOS to Linux can be determined only in NMI, IRQ or timer
@@ -1388,7 +1391,11 @@ static int ghes_probe(struct platform_device *ghes_dev)
 
 	platform_set_drvdata(ghes_dev, ghes);
 
-	ghes_edac_register(ghes, &ghes_dev->dev);
+	ghes->dev = &ghes_dev->dev;
+
+	mutex_lock(&ghes_devs_mutex);
+	list_add_tail(&ghes->elist, &ghes_devs);
+	mutex_unlock(&ghes_devs_mutex);
 
 	ghes_present = true;
 
@@ -1454,7 +1461,9 @@ static int ghes_remove(struct platform_device *ghes_dev)
 
 	ghes_fini(ghes);
 
-	ghes_edac_unregister(ghes);
+	mutex_lock(&ghes_devs_mutex);
+	list_del(&ghes->elist);
+	mutex_unlock(&ghes_devs_mutex);
 
 	kfree(ghes);
 
@@ -1537,6 +1546,15 @@ bool ghes_edac_preferred(void)
 }
 EXPORT_SYMBOL_GPL(ghes_edac_preferred);
 
+struct list_head *ghes_get_devices(void)
+{
+	if (!ghes_edac_preferred())
+		return NULL;
+
+	return &ghes_devs;
+}
+EXPORT_SYMBOL_GPL(ghes_get_devices);
+
 void ghes_register_report_chain(struct notifier_block *nb)
 {
 	atomic_notifier_chain_register(&ghes_report_chain, nb);
diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 17562cf1fe97..df45db81858b 100644
--- a/drivers/edac/Kconfig
+++ b/drivers/edac/Kconfig
@@ -53,8 +53,8 @@ config EDAC_DECODE_MCE
 	  has been initialized.
 
 config EDAC_GHES
-	bool "Output ACPI APEI/GHES BIOS detected errors via EDAC"
-	depends on ACPI_APEI_GHES && (EDAC=y)
+	tristate "Output ACPI APEI/GHES BIOS detected errors via EDAC"
+	depends on ACPI_APEI_GHES
 	select UEFI_CPER
 	help
 	  Not all machines support hardware-driven error report. Some of those
diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c
index 11a1b5e7e484..129665896a80 100644
--- a/drivers/edac/ghes_edac.c
+++ b/drivers/edac/ghes_edac.c
@@ -56,6 +56,8 @@ static DEFINE_SPINLOCK(ghes_lock);
 
 static bool system_scanned;
 
+static struct list_head *ghes_devs;
+
 /* Memory Device - Type 17 of SMBIOS spec */
 struct memdev_dmi_entry {
 	u8 type;
@@ -383,34 +385,15 @@ static struct notifier_block ghes_edac_mem_err_nb = {
 	.priority	= 0,
 };
 
-/*
- * Known systems that are safe to enable this module.
- */
-static struct acpi_platform_list plat_list[] = {
-	{"HPE   ", "Server  ", 0, ACPI_SIG_FADT, all_versions},
-	{ } /* End */
-};
-
-int ghes_edac_register(struct ghes *ghes, struct device *dev)
+static int ghes_edac_register(struct device *dev)
 {
 	bool fake = false;
 	struct mem_ctl_info *mci;
 	struct ghes_pvt *pvt;
 	struct edac_mc_layer layers[1];
 	unsigned long flags;
-	int idx = -1;
 	int rc = 0;
 
-	if (IS_ENABLED(CONFIG_X86)) {
-		/* Check if safe to enable on this system */
-		idx = acpi_match_platform_list(plat_list);
-		if (!ghes_edac_force_enable && idx < 0)
-			return -ENODEV;
-	} else {
-		ghes_edac_force_enable = true;
-		idx = 0;
-	}
-
 	/* finish another registration/unregistration instance first */
 	mutex_lock(&ghes_reg_mutex);
 
@@ -454,7 +437,7 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 		pr_info("This system has a very crappy BIOS: It doesn't even list the DIMMS.\n");
 		pr_info("Its SMBIOS info is wrong. It is doubtful that the error report would\n");
 		pr_info("work on such system. Use this driver with caution\n");
-	} else if (idx < 0) {
+	} else if (ghes_edac_force_enable) {
 		pr_info("This EDAC driver relies on BIOS to enumerate memory and get error reports.\n");
 		pr_info("Unfortunately, not all BIOSes reflect the memory layout correctly.\n");
 		pr_info("So, the end result of using this driver varies from vendor to vendor.\n");
@@ -526,14 +509,11 @@ int ghes_edac_register(struct ghes *ghes, struct device *dev)
 	return rc;
 }
 
-void ghes_edac_unregister(struct ghes *ghes)
+static void ghes_edac_unregister(struct ghes *ghes)
 {
 	struct mem_ctl_info *mci;
 	unsigned long flags;
 
-	if (!ghes_edac_force_enable)
-		return;
-
 	mutex_lock(&ghes_reg_mutex);
 
 	system_scanned = false;
@@ -562,3 +542,32 @@ void ghes_edac_unregister(struct ghes *ghes)
 unlock:
 	mutex_unlock(&ghes_reg_mutex);
 }
+
+static int __init ghes_edac_init(void)
+{
+	struct ghes *g, *g_tmp;
+
+	ghes_devs = ghes_get_devices();
+	if (!ghes_devs)
+		return -ENODEV;
+
+	list_for_each_entry_safe(g, g_tmp, ghes_devs, elist) {
+		ghes_edac_register(g->dev);
+	}
+
+	return 0;
+}
+module_init(ghes_edac_init);
+
+static void __exit ghes_edac_exit(void)
+{
+	struct ghes *g, *g_tmp;
+
+	list_for_each_entry_safe(g, g_tmp, ghes_devs, elist) {
+		ghes_edac_unregister(g);
+	}
+}
+module_exit(ghes_edac_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Output ACPI APEI/GHES BIOS detected errors module via EDAC");
diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
index 7ce91c0ff3eb..08f12dde99ae 100644
--- a/include/acpi/ghes.h
+++ b/include/acpi/ghes.h
@@ -27,6 +27,8 @@ struct ghes {
 		struct timer_list timer;
 		unsigned int irq;
 	};
+	struct device *dev;
+	struct list_head elist;
 };
 
 struct ghes_estatus_node {
@@ -69,30 +71,16 @@ int ghes_register_vendor_record_notifier(struct notifier_block *nb);
  * @nb: pointer to the notifier_block structure of the vendor record handler.
  */
 void ghes_unregister_vendor_record_notifier(struct notifier_block *nb);
-#endif
-
-int ghes_estatus_pool_init(int num_ghes);
-
-/* From drivers/edac/ghes_edac.c */
-
-#ifdef CONFIG_EDAC_GHES
-int ghes_edac_register(struct ghes *ghes, struct device *dev);
-
-void ghes_edac_unregister(struct ghes *ghes);
 
+struct list_head *ghes_get_devices(void);
 bool ghes_edac_preferred(void);
 #else
-static inline int ghes_edac_register(struct ghes *ghes, struct device *dev)
-{
-	return -ENODEV;
-}
-
-static inline void ghes_edac_unregister(struct ghes *ghes)
-{
-}
+static inline struct list_head *ghes_get_devices(void) { return NULL; }
 static bool ghes_edac_preferred(void) { return false; }
 #endif
 
+int ghes_estatus_pool_init(int num_ghes);
+
 static inline int acpi_hest_get_version(struct acpi_hest_generic_data *gdata)
 {
 	return gdata->revision >> 8;
-- 
2.25.1

[PATCH v5 6/8] EDAC: Add the ghes_edac_preferred check for chipset-specific edac drivers

[Jia He]

Add ghes_edac_preferred() check to chipset-specific edac drivers to ensure
that ghes_edac is used on the platform where ghes_edac is preferred over
chipset-specific edac driver.

Unlike the existing edac_get_owner() check, the ghes_edac_preferred()
check works independent to the module_init ordering.

Suggested-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Jia He <justin.he@arm.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
---
 drivers/edac/amd64_edac.c      | 3 +++
 drivers/edac/armada_xp_edac.c  | 3 +++
 drivers/edac/edac_module.h     | 1 +
 drivers/edac/i10nm_base.c      | 3 +++
 drivers/edac/igen6_edac.c      | 3 +++
 drivers/edac/layerscape_edac.c | 3 +++
 drivers/edac/pnd2_edac.c       | 3 +++
 drivers/edac/sb_edac.c         | 3 +++
 drivers/edac/skx_base.c        | 3 +++
 drivers/edac/thunderx_edac.c   | 3 +++
 drivers/edac/xgene_edac.c      | 3 +++
 11 files changed, 31 insertions(+)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 2f854feeeb23..5314a934c2bf 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -4329,6 +4329,9 @@ static int __init amd64_edac_init(void)
 	int err = -ENODEV;
 	int i;
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	owner = edac_get_owner();
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -EBUSY;
diff --git a/drivers/edac/armada_xp_edac.c b/drivers/edac/armada_xp_edac.c
index 038abbb83f4b..486532b92ce0 100644
--- a/drivers/edac/armada_xp_edac.c
+++ b/drivers/edac/armada_xp_edac.c
@@ -599,6 +599,9 @@ static int __init armada_xp_edac_init(void)
 {
 	int res;
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	/* only polling is supported */
 	edac_op_state = EDAC_OPSTATE_POLL;
 
diff --git a/drivers/edac/edac_module.h b/drivers/edac/edac_module.h
index 96f6de0c8ff6..3826f82de487 100644
--- a/drivers/edac/edac_module.h
+++ b/drivers/edac/edac_module.h
@@ -11,6 +11,7 @@
 #ifndef	__EDAC_MODULE_H__
 #define	__EDAC_MODULE_H__
 
+#include <acpi/ghes.h>
 #include "edac_mc.h"
 #include "edac_pci.h"
 #include "edac_device.h"
diff --git a/drivers/edac/i10nm_base.c b/drivers/edac/i10nm_base.c
index 6cf50ee0b77c..691df9b51622 100644
--- a/drivers/edac/i10nm_base.c
+++ b/drivers/edac/i10nm_base.c
@@ -548,6 +548,9 @@ static int __init i10nm_init(void)
 
 	edac_dbg(2, "\n");
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	owner = edac_get_owner();
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -EBUSY;
diff --git a/drivers/edac/igen6_edac.c b/drivers/edac/igen6_edac.c
index a07bbfd075d0..4ac6d0c533ec 100644
--- a/drivers/edac/igen6_edac.c
+++ b/drivers/edac/igen6_edac.c
@@ -1271,6 +1271,9 @@ static int __init igen6_init(void)
 
 	edac_dbg(2, "\n");
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	owner = edac_get_owner();
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -ENODEV;
diff --git a/drivers/edac/layerscape_edac.c b/drivers/edac/layerscape_edac.c
index 94cac7686a56..60ff4c6674cd 100644
--- a/drivers/edac/layerscape_edac.c
+++ b/drivers/edac/layerscape_edac.c
@@ -38,6 +38,9 @@ static int __init fsl_ddr_mc_init(void)
 {
 	int res;
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	/* make sure error reporting method is sane */
 	switch (edac_op_state) {
 	case EDAC_OPSTATE_POLL:
diff --git a/drivers/edac/pnd2_edac.c b/drivers/edac/pnd2_edac.c
index a20b299f1202..4ddc43e6c420 100644
--- a/drivers/edac/pnd2_edac.c
+++ b/drivers/edac/pnd2_edac.c
@@ -1528,6 +1528,9 @@ static int __init pnd2_init(void)
 
 	edac_dbg(2, "\n");
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	owner = edac_get_owner();
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -EBUSY;
diff --git a/drivers/edac/sb_edac.c b/drivers/edac/sb_edac.c
index 9678ab97c7ac..3ff604a5e95a 100644
--- a/drivers/edac/sb_edac.c
+++ b/drivers/edac/sb_edac.c
@@ -3506,6 +3506,9 @@ static int __init sbridge_init(void)
 
 	edac_dbg(2, "\n");
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	owner = edac_get_owner();
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -EBUSY;
diff --git a/drivers/edac/skx_base.c b/drivers/edac/skx_base.c
index 1abc020d49ab..286370728552 100644
--- a/drivers/edac/skx_base.c
+++ b/drivers/edac/skx_base.c
@@ -653,6 +653,9 @@ static int __init skx_init(void)
 
 	edac_dbg(2, "\n");
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	owner = edac_get_owner();
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
 		return -EBUSY;
diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c
index f13674081cb6..2c4baa6817a9 100644
--- a/drivers/edac/thunderx_edac.c
+++ b/drivers/edac/thunderx_edac.c
@@ -2114,6 +2114,9 @@ static int __init thunderx_edac_init(void)
 {
 	int rc = 0;
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	rc = pci_register_driver(&thunderx_lmc_driver);
 	if (rc)
 		return rc;
diff --git a/drivers/edac/xgene_edac.c b/drivers/edac/xgene_edac.c
index 54081403db4f..9aa68220b625 100644
--- a/drivers/edac/xgene_edac.c
+++ b/drivers/edac/xgene_edac.c
@@ -2004,6 +2004,9 @@ static int __init xgene_edac_init(void)
 {
 	int rc;
 
+	if (ghes_edac_preferred())
+		return -EBUSY;
+
 	/* Make sure error reporting method is sane */
 	switch (edac_op_state) {
 	case EDAC_OPSTATE_POLL:
-- 
2.25.1

[PATCH v5 7/8] apei/ghes: Use unrcu_pointer for cmpxchg

[Jia He]

ghes_estatus_caches should be add rcu annotation to avoid sparse warnings.
   drivers/acpi/apei/ghes.c:733:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/acpi/apei/ghes.c:733:25: sparse:    struct ghes_estatus_cache [noderef] __rcu *
   drivers/acpi/apei/ghes.c:733:25: sparse:    struct ghes_estatus_cache *
   drivers/acpi/apei/ghes.c:813:25: sparse: sparse: incompatible types in comparison expression (different address spaces):
   drivers/acpi/apei/ghes.c:813:25: sparse:    struct ghes_estatus_cache [noderef] __rcu *
   drivers/acpi/apei/ghes.c:813:25: sparse:    struct ghes_estatus_cache *

unrcu_pointer is to strip the __rcu in cmpxchg.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Jia He <justin.he@arm.com>
---
 drivers/acpi/apei/ghes.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 4af269b22bd4..c0b09addb96f 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -153,7 +153,7 @@ struct ghes_vendor_record_entry {
 static struct gen_pool *ghes_estatus_pool;
 static unsigned long ghes_estatus_pool_size_request;
 
-static struct ghes_estatus_cache *ghes_estatus_caches[GHES_ESTATUS_CACHES_SIZE];
+static struct ghes_estatus_cache __rcu *ghes_estatus_caches[GHES_ESTATUS_CACHES_SIZE];
 static atomic_t ghes_estatus_cache_alloced;
 
 static int ghes_panic_timeout __read_mostly = 30;
@@ -843,8 +843,9 @@ static void ghes_estatus_cache_add(
 	}
 	/* new_cache must be put into array after its contents are written */
 	smp_wmb();
-	if (slot != -1 && cmpxchg(ghes_estatus_caches + slot,
-				  slot_cache, new_cache) == slot_cache) {
+	if (slot != -1 && unrcu_pointer(cmpxchg(ghes_estatus_caches + slot,
+				RCU_INITIALIZER(slot_cache),
+				RCU_INITIALIZER(new_cache))) == slot_cache) {
 		if (slot_cache)
 			call_rcu(&slot_cache->rcu, ghes_estatus_cache_rcu_free);
 	} else
-- 
2.25.1

[PATCH v5 8/8] EDAC/igen6: Return consistent errno when another edac driver is enabled

[Jia He]

Only a single edac driver can be enabled for EDAC MC. The igen6_init()
should be returned with EBUSY instead of ENODEV, which is consistent with
other edac drivers.

Signed-off-by: Jia He <justin.he@arm.com>
---
 drivers/edac/igen6_edac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/edac/igen6_edac.c b/drivers/edac/igen6_edac.c
index 4ac6d0c533ec..4646cb72b9f8 100644
--- a/drivers/edac/igen6_edac.c
+++ b/drivers/edac/igen6_edac.c
@@ -1276,7 +1276,7 @@ static int __init igen6_init(void)
 
 	owner = edac_get_owner();
 	if (owner && strncmp(owner, EDAC_MOD_STR, sizeof(EDAC_MOD_STR)))
-		return -ENODEV;
+		return -EBUSY;
 
 	edac_op_state = EDAC_OPSTATE_NMI;
 
-- 
2.25.1

RE: [PATCH v5 3/8] EDAC:ghes: Move ghes_edac.force_load to ghes module parameter

[Kani, Toshi]

On Monday, September 5, 2022 9:25 AM, Jia He wrote:
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 8cb65f757d06..b0a6445c6da2 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -109,6 +109,14 @@ static inline bool is_hest_type_generic_v2(struct
> ghes *ghes)
>  bool ghes_disable;
>  module_param_named(disable, ghes_disable, bool, 0);
> 
> +/*
> + * "ghes.edac_force_enable" forcibly enables ghes_edac and skips the
> platform
> + * check.
> + */
> +bool ghes_edac_force_enable;
> +EXPORT_SYMBOL(ghes_edac_force_enable);
> +module_param_named(edac_force_enable, ghes_edac_force_enable,
> bool, 0);

Thanks for the update.  It looks good to me.
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>

Toshi

RE: [PATCH v5 5/8] EDAC/ghes: Make ghes_edac a proper module to remove the dependency on ghes

[Kani, Toshi]

On Monday, September 5, 2022 9:25 AM, Jia He wrote:
> -void ghes_edac_unregister(struct ghes *ghes)
> +static void ghes_edac_unregister(struct ghes *ghes)
>  {
>  	struct mem_ctl_info *mci;
>  	unsigned long flags;
> 
> -	if (!ghes_edac_force_enable)
> -		return;
> -

I am not familiar with this original check.  Assuming it is safe to
delete it now (as you mentioned in other email w/o description),
I suggest adding some description to the commit log.

At high-level, the patch looks good to me.
Acked-by: Toshi Kani <toshi.kani@hpe.com>

Toshi

RE: [PATCH v5 5/8] EDAC/ghes: Make ghes_edac a proper module to remove the dependency on ghes

[Justin He]

Hi Kani

> -----Original Message-----
> From: Kani, Toshi <toshi.kani@hpe.com>
> Sent: Thursday, September 8, 2022 8:31 AM
> To: Justin He <Justin.He@arm.com>; Len Brown <lenb@kernel.org>; James
> Morse <James.Morse@arm.com>; Tony Luck <tony.luck@intel.com>; Borislav
> Petkov <bp@alien8.de>; Mauro Carvalho Chehab <mchehab@kernel.org>;
> Robert Richter <rric@kernel.org>; Robert Moore <robert.moore@intel.com>;
> Qiuxu Zhuo <qiuxu.zhuo@intel.com>; Yazen Ghannam
> <yazen.ghannam@amd.com>; Jan Luebbe <jlu@pengutronix.de>; Khuong
> Dinh <khuong@os.amperecomputing.com>
> Cc: Ard Biesheuvel <ardb@kernel.org>; linux-acpi@vger.kernel.org;
> linux-kernel@vger.kernel.org; linux-edac@vger.kernel.org; devel@acpica.org;
> Rafael J . Wysocki <rafael@kernel.org>; Shuai Xue
> <xueshuai@linux.alibaba.com>; Jarkko Sakkinen <jarkko@kernel.org>;
> linux-efi@vger.kernel.org; nd <nd@arm.com>
> Subject: RE: [PATCH v5 5/8] EDAC/ghes: Make ghes_edac a proper module to
> remove the dependency on ghes
> 
> On Monday, September 5, 2022 9:25 AM, Jia He wrote:
> > -void ghes_edac_unregister(struct ghes *ghes)
> > +static void ghes_edac_unregister(struct ghes *ghes)
> >  {
> >  	struct mem_ctl_info *mci;
> >  	unsigned long flags;
> >
> > -	if (!ghes_edac_force_enable)
> > -		return;
> > -
> 
> I am not familiar with this original check.  Assuming it is safe to delete it now
> (as you mentioned in other email w/o description), I suggest adding some
> description to the commit log.
> 
Thanks, will do
I've tested the insmod/rmmod multiple times on Arm host.

I will wait for others' comments for a while before sending the new version.
> At high-level, the patch looks good to me.
> Acked-by: Toshi Kani <toshi.kani@hpe.com>

Thanks a lot for the help 😊

--
Cheers,
Justin (Jia He)