EDAC/ghes: Make ghes_edac a proper module

Commit

  dc4e8c07e9e2 ("ACPI: APEI: explicit init of HEST and GHES in apci_init()")

introduced a bug leading to ghes_edac_register() to be invoked before
edac_init(). Because at that time the bus "edac" hadn't been even
registered, this created sysfs nodes as /devices/mc0 instead of
/sys/devices/system/edac/mc/mc0 on an Ampere eMag server.

Fix this by turning ghes_edac into a proper module.

The list of GHES devices returned is not protected from being modified
concurrently but it is pretty static as it gets created only during GHES
init and latter is not a module so...

  [ bp: Massage. ]

Fixes: dc4e8c07e9e2 ("ACPI: APEI: explicit init of HEST and GHES in apci_init()")
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>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221010023559.69655-5-justin.he@arm.com

3 files changed, 40 insertions, 8 deletions

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index acab512741f6..249cd01cb920 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -1392,8 +1392,6 @@ 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);
@@ -1462,8 +1460,6 @@ 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);
diff --git a/drivers/edac/Kconfig b/drivers/edac/Kconfig
index 456602d373b7..cde0849cf861 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 b85a545d1cb0..cf2b618c1ada 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;
@@ -383,7 +385,7 @@ static struct notifier_block ghes_edac_mem_err_nb = {
 	.priority	= 0,
 };
 
-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;
@@ -502,7 +504,7 @@ unlock:
 	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;
@@ -535,3 +537,37 @@ 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;
+
+	if (list_empty(ghes_devs)) {
+		pr_info("GHES probing device list is empty");
+		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 via EDAC");