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

arch/x86/kernel/cpu/mce/core.c

@@ -544,21 +544,6 @@ bool mce_is_correctable(struct mce *m)
 }
 EXPORT_SYMBOL_GPL(mce_is_correctable);
 
-static bool cec_add_mce(struct mce *m)
-{
-	if (!m)
-		return false;
-
-	/* 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 true;
-
-	return false;
-}
-
 static int mce_early_notifier(struct notifier_block *nb, unsigned long val,
 			      void *data)
 {
@@ -567,9 +552,6 @@ static int mce_early_notifier(struct notifier_block *nb, unsigned long val,
 	if (!m)
 		return NOTIFY_DONE;
 
-	if (cec_add_mce(m))
-		return NOTIFY_STOP;
-
 	/* Emit the trace record: */
 	trace_mce_record(m);
 
@@ -2612,7 +2594,6 @@ static int __init mcheck_late_init(void)
 		static_branch_inc(&mcsafe_key);
 
 	mcheck_debugfs_init();
-	cec_init();
 
 	/*
 	 * Flush out everything that has been logged during early boot, now that

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 @@ static int __init create_debugfs_nodes(void)
 	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)
 {

include/linux/ras.h

@@ -17,12 +17,7 @@ static inline int ras_add_daemon_trace(void) { return 0; }
 #endif
 
 #ifdef CONFIG_RAS_CEC
-void __init cec_init(void);
 int __init parse_cec_param(char *str);
-int cec_add_elem(u64 pfn);
-#else
-static inline void __init cec_init(void)	{ }
-static inline int cec_add_elem(u64 pfn)		{ return -ENODEV; }
 #endif
 
 #ifdef CONFIG_RAS