[v7,1/6] ACPI / APEI: Add support to queuing up the non-fatal HW errors and notify

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 24c9642e8fc7..5c0ab5422311 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -33,6 +33,7 @@ 
 #include <linux/irq_work.h>
 #include <linux/llist.h>
 #include <linux/genalloc.h>
+#include <linux/kfifo.h>
 #include <linux/pci.h>
 #include <linux/pfn.h>
 #include <linux/aer.h>
@@ -63,6 +64,11 @@ 
 #define GHES_ESTATUS_CACHES_SIZE	4
 
 #define GHES_ESTATUS_IN_CACHE_MAX_NSEC	10000000000ULL
+
+#define GHES_EVENT_RING_SIZE	256
+#define GHES_GDATA_POOL_MIN_ALLOC_ORDER	3
+#define GHES_GDATA_POOL_MIN_SIZE	65536
+
 /* Prevent too many caches are allocated because of RCU */
 #define GHES_ESTATUS_CACHE_ALLOCED_MAX	(GHES_ESTATUS_CACHES_SIZE * 3 / 2)
 
@@ -122,6 +128,19 @@  static DEFINE_MUTEX(ghes_list_mutex);
  */
 static DEFINE_SPINLOCK(ghes_notify_lock_irq);
 
+struct ghes_event_entry {
+	struct acpi_hest_generic_data *gdata;
+	int error_severity;
+};
+
+static DEFINE_KFIFO(ghes_event_ring, struct ghes_event_entry,
+		    GHES_EVENT_RING_SIZE);
+
+static DEFINE_SPINLOCK(ghes_event_ring_lock);
+
+static struct gen_pool *ghes_gdata_pool;
+static unsigned long ghes_gdata_pool_size_request;
+
 static struct gen_pool *ghes_estatus_pool;
 static unsigned long ghes_estatus_pool_size_request;
 
@@ -188,6 +207,40 @@  int ghes_estatus_pool_init(int num_ghes)
 	return -ENOMEM;
 }
 
+int ghes_gdata_pool_init(void)
+{
+	unsigned long addr, len;
+	int rc;
+
+	ghes_gdata_pool = gen_pool_create(GHES_GDATA_POOL_MIN_ALLOC_ORDER, -1);
+	if (!ghes_gdata_pool)
+		return -ENOMEM;
+
+	if (ghes_gdata_pool_size_request < GHES_GDATA_POOL_MIN_SIZE)
+		ghes_gdata_pool_size_request = GHES_GDATA_POOL_MIN_SIZE;
+
+	len = ghes_gdata_pool_size_request;
+	addr = (unsigned long)vmalloc(PAGE_ALIGN(len));
+	if (!addr)
+		goto err_pool_alloc;
+
+	vmalloc_sync_mappings();
+
+	rc = gen_pool_add(ghes_gdata_pool, addr, PAGE_ALIGN(len), -1);
+	if (rc)
+		goto err_pool_add;
+
+	return 0;
+
+err_pool_add:
+	vfree((void *)addr);
+
+err_pool_alloc:
+	gen_pool_destroy(ghes_gdata_pool);
+
+	return -ENOMEM;
+}
+
 static int map_gen_v2(struct ghes *ghes)
 {
 	return apei_map_generic_address(&ghes->generic_v2->read_ack_register);
@@ -247,6 +300,10 @@  static struct ghes *ghes_new(struct acpi_hest_generic *generic)
 		goto err_unmap_status_addr;
 	}
 
+	ghes_gdata_pool_size_request += generic->records_to_preallocate *
+					generic->max_sections_per_record *
+					generic->max_raw_data_length;
+
 	return ghes;
 
 err_unmap_status_addr:
@@ -490,6 +547,49 @@  static void ghes_handle_aer(struct acpi_hest_generic_data *gdata)
 #endif
 }
 
+static BLOCKING_NOTIFIER_HEAD(ghes_event_notify_list);
+
+/**
+ * ghes_register_event_notifier - register an event notifier
+ * for the non-fatal HW errors.
+ * @nb: pointer to the notifier_block structure of the event handler.
+ *
+ * return 0 : SUCCESS, non-zero : FAIL
+ */
+int ghes_register_event_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&ghes_event_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(ghes_register_event_notifier);
+
+/**
+ * ghes_unregister_event_notifier - unregister the previously
+ * registered event notifier.
+ * @nb: pointer to the notifier_block structure of the event handler.
+ */
+void ghes_unregister_event_notifier(struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&ghes_event_notify_list, nb);
+}
+EXPORT_SYMBOL_GPL(ghes_unregister_event_notifier);
+
+static void ghes_event_work_func(struct work_struct *work)
+{
+	struct ghes_event_entry entry;
+	u32 len;
+
+	while (kfifo_get(&ghes_event_ring, &entry)) {
+		blocking_notifier_call_chain(&ghes_event_notify_list,
+					     entry.error_severity,
+					     entry.gdata);
+		len = acpi_hest_get_size(entry.gdata) +
+				acpi_hest_get_error_length(entry.gdata);
+		gen_pool_free(ghes_gdata_pool, (unsigned long)entry.gdata, len);
+	}
+}
+
+static DECLARE_WORK(ghes_event_work, ghes_event_work_func);
+
 static void ghes_do_proc(struct ghes *ghes,
 			 const struct acpi_hest_generic_status *estatus)
 {
@@ -498,6 +598,8 @@  static void ghes_do_proc(struct ghes *ghes,
 	guid_t *sec_type;
 	const guid_t *fru_id = &guid_null;
 	char *fru_text = "";
+	struct ghes_event_entry event_entry;
+	u32 len;
 
 	sev = ghes_severity(estatus->error_severity);
 	apei_estatus_for_each_section(estatus, gdata) {
@@ -509,6 +611,25 @@  static void ghes_do_proc(struct ghes *ghes,
 		if (gdata->validation_bits & CPER_SEC_VALID_FRU_TEXT)
 			fru_text = gdata->fru_text;
 
+		len = acpi_hest_get_record_size(gdata);
+		event_entry.gdata = (void *)gen_pool_alloc(ghes_gdata_pool,
+							   len);
+		if (!event_entry.gdata) {
+			pr_warn(GHES_PFX "ghes gdata pool alloc fail\n");
+			break;
+		}
+
+		memcpy(event_entry.gdata, gdata, len);
+		event_entry.error_severity = sev;
+
+		if (kfifo_in_spinlocked(&ghes_event_ring, &event_entry, 1,
+					&ghes_event_ring_lock))
+			schedule_work(&ghes_event_work);
+		else {
+			pr_warn(GHES_PFX "ghes event queue full\n");
+			break;
+		}
+
 		if (guid_equal(sec_type, &CPER_SEC_PLATFORM_MEM)) {
 			struct cper_sec_mem_err *mem_err = acpi_hest_get_payload(gdata);
 
@@ -1346,6 +1467,12 @@  static int __init ghes_init(void)
 	else
 		pr_info(GHES_PFX "Failed to enable APEI firmware first mode.\n");
 
+	rc = ghes_gdata_pool_init();
+	if (rc) {
+		pr_warn(GHES_PFX "ghes_gdata_pool_init failed\n");
+		goto err;
+	}
+
 	return 0;
 err:
 	return rc;
diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
index e3f1cddb4ac8..a3dd82069069 100644
--- a/include/acpi/ghes.h
+++ b/include/acpi/ghes.h
@@ -50,6 +50,34 @@  enum {
 	GHES_SEV_PANIC = 0x3,
 };
 
+
+#ifdef CONFIG_ACPI_APEI_GHES
+/**
+ * ghes_register_event_notifier - register an event notifier
+ * for the non-fatal HW errors.
+ * @nb: pointer to the notifier_block structure of the event notifier.
+ *
+ * Return : 0 - SUCCESS, non-zero - FAIL.
+ */
+int ghes_register_event_notifier(struct notifier_block *nb);
+
+/**
+ * ghes_unregister_event_notifier - unregister the previously
+ * registered event notifier.
+ * @nb: pointer to the notifier_block structure of the event notifier.
+ */
+void ghes_unregister_event_notifier(struct notifier_block *nb);
+#else
+static inline int ghes_register_event_notifier(struct notifier_block *nb)
+{
+	return -ENODEV;
+}
+
+static inline void ghes_unregister_event_notifier(struct notifier_block *nb)
+{
+}
+#endif
+
 int ghes_estatus_pool_init(int num_ghes);
 
 /* From drivers/edac/ghes_edac.c */