x86/mce: Convert the CEC to use the MCE notifier

The CEC code has its claws in a couple of routines in mce/core.c.
Convert it to just register itself on the normal MCE notifier chain.

 [ bp: Make cec_add_elem() and cec_init() static. ]

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20200214222720.13168-3-tony.luck@intel.com

drivers/ras/cec.c

@@ -309,7 +309,7 @@ static bool sanity_check(struct ce_array *ca)
 	return ret;
 }
 
-int cec_add_elem(u64 pfn)
+static int cec_add_elem(u64 pfn)
 {
 	struct ce_array *ca = &ce_arr;
 	unsigned int to = 0;
@@ -527,7 +527,30 @@ err:
 	return 1;
 }
 
-void __init cec_init(void)
+static int cec_notifier(struct notifier_block *nb, unsigned long val,
+			void *data)
+{
+	struct mce *m = (struct mce *)data;
+
+	if (!m)
+		return NOTIFY_DONE;
+
+	/* We eat only correctable DRAM errors with usable addresses. */
+	if (mce_is_memory_error(m) &&
+	    mce_is_correctable(m)  &&
+	    mce_usable_address(m))
+		if (!cec_add_elem(m->addr >> PAGE_SHIFT))
+			return NOTIFY_STOP;
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block cec_nb = {
+	.notifier_call	= cec_notifier,
+	.priority	= MCE_PRIO_CEC,
+};
+
+static void __init cec_init(void)
 {
 	if (ce_arr.disabled)
 		return;
@@ -546,8 +569,11 @@ void __init cec_init(void)
 	INIT_DELAYED_WORK(&cec_work, cec_work_fn);
 	schedule_delayed_work(&cec_work, CEC_DECAY_DEFAULT_INTERVAL);
 
+	mce_register_decode_chain(&cec_nb);
+
 	pr_info("Correctable Errors collector initialized.\n");
 }
+late_initcall(cec_init);
 
 int __init parse_cec_param(char *str)
 {