[PATCH v4 4/8] ghes: Introduce a helper ghes_edac_preferred()

[Jia He <justin.he@arm.com>]

Introduce a flag ghes_present to differentiate between the system ROM
really not offering GHES vs. the ghes module not running. ghes-present
is latched on ghes_probe() and never unlatched since ACPI GHES table
is static.

Introduce a helper ghes_edac_preferred() and it is true if the
platform-check passes.

Suggested-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Jia He <justin.he@arm.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 6bc9c78f916b..d798a58fbbd9 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -117,6 +117,8 @@ bool ghes_edac_force_load;
 module_param_named(edac_force_load, ghes_edac_force_load, bool, 0);
 EXPORT_SYMBOL(ghes_edac_force_load);
 
+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);
@@ -1511,6 +1515,31 @@ 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_load)
+			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