EDAC/ghes: Prepare to make ghes_edac a proper module

To make ghes_edac a proper module, prepare to decouple its dependencies
from GHES.

Move the ghes_edac.force_load parameter to ghes.c in order to
properly control whether ghes_edac should be force-loaded: In
ghes_edac_register() it is too late to set the module flag.

Introduce a helper ghes_get_devices(), which returns the list of GHES
devices which got probed when the platform-check passes on the system.

The previous force_load check is not needed in ghes_edac_unregister()
since it will be checked in the module's init function of ghes_edac
later.

  [ bp: Massage. ]

Suggested-by: Toshi Kani <toshi.kani@hpe.com>
Suggested-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/20221010023559.69655-4-justin.he@arm.com

1 files changed, 50 insertions, 0 deletions

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 55013e024ba3..acab512741f6 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -110,6 +110,13 @@ bool ghes_disable;
 module_param_named(disable, ghes_disable, bool, 0);
 
 /*
+ * "ghes.edac_force_enable" forcibly enables ghes_edac and skips the platform
+ * check.
+ */
+static bool 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
  * by one. This holds true for NMI too.
@@ -121,6 +128,13 @@ static LIST_HEAD(ghes_hed);
 static DEFINE_MUTEX(ghes_list_mutex);
 
 /*
+ * A list of GHES devices which are given to the corresponding EDAC driver
+ * ghes_edac for further use.
+ */
+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
  * handler, but general ioremap can not be used in atomic context, so
@@ -1380,6 +1394,12 @@ static int ghes_probe(struct platform_device *ghes_dev)
 
 	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);
+
 	/* Handle any pending errors right away */
 	spin_lock_irqsave(&ghes_notify_lock_irq, flags);
 	ghes_proc(ghes);
@@ -1444,6 +1464,10 @@ static int ghes_remove(struct platform_device *ghes_dev)
 
 	ghes_edac_unregister(ghes);
 
+	mutex_lock(&ghes_devs_mutex);
+	list_del(&ghes->elist);
+	mutex_unlock(&ghes_devs_mutex);
+
 	kfree(ghes);
 
 	platform_set_drvdata(ghes_dev, NULL);
@@ -1500,6 +1524,32 @@ 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 */
+};
+
+struct list_head *ghes_get_devices(void)
+{
+	int idx = -1;
+
+	if (IS_ENABLED(CONFIG_X86)) {
+		idx = acpi_match_platform_list(plat_list);
+		if (idx < 0) {
+			if (!ghes_edac_force_enable)
+				return NULL;
+
+			pr_warn_once("Force-loading ghes_edac on an unsupported platform. You're on your own!\n");
+		}
+	}
+
+	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);