x86, mce: Add wrappers for registering on the decode chain

No functionality change, this is done so that in a follow-on patch all
queued-up MCEs can be decoded after registering on the chain.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>

arch/x86/include/asm/mce.h

@@ -120,7 +120,8 @@ struct mce_log {
 
 #ifdef __KERNEL__
 
-extern struct atomic_notifier_head x86_mce_decoder_chain;
+extern void mce_register_decode_chain(struct notifier_block *nb);
+extern void mce_unregister_decode_chain(struct notifier_block *nb);
 
 #include <linux/percpu.h>
 #include <linux/init.h>

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

@@ -95,20 +95,19 @@ static DECLARE_WAIT_QUEUE_HEAD(mce_chrdev_wait);
 static DEFINE_PER_CPU(struct mce, mces_seen);
 static int			cpu_missing;
 
-/*
- * CPU/chipset specific EDAC code can register a notifier call here to print
- * MCE errors in a human-readable form.
- */
-ATOMIC_NOTIFIER_HEAD(x86_mce_decoder_chain);
-EXPORT_SYMBOL_GPL(x86_mce_decoder_chain);
-
 /* MCA banks polled by the period polling timer for corrected events */
 DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = {
 	[0 ... BITS_TO_LONGS(MAX_NR_BANKS)-1] = ~0UL
 };
 
 static DEFINE_PER_CPU(struct work_struct, mce_work);
 
+/*
+ * CPU/chipset specific EDAC code can register a notifier call here to print
+ * MCE errors in a human-readable form.
+ */
+ATOMIC_NOTIFIER_HEAD(x86_mce_decoder_chain);
+
 /* Do initial initialization of a struct mce */
 void mce_setup(struct mce *m)
 {
@@ -190,6 +189,18 @@ void mce_log(struct mce *mce)
 	set_bit(0, &mce_need_notify);
 }
 
+void mce_register_decode_chain(struct notifier_block *nb)
+{
+	atomic_notifier_chain_register(&x86_mce_decoder_chain, nb);
+}
+EXPORT_SYMBOL_GPL(mce_register_decode_chain);
+
+void mce_unregister_decode_chain(struct notifier_block *nb)
+{
+	atomic_notifier_chain_unregister(&x86_mce_decoder_chain, nb);
+}
+EXPORT_SYMBOL_GPL(mce_unregister_decode_chain);
+
 static void print_mce(struct mce *m)
 {
 	int ret = 0;

drivers/edac/i7core_edac.c

@@ -2234,7 +2234,7 @@ static void i7core_unregister_mci(struct i7core_dev *i7core_dev)
 	if (pvt->enable_scrub)
 		disable_sdram_scrub_setting(mci);
 
-	atomic_notifier_chain_unregister(&x86_mce_decoder_chain, &i7_mce_dec);
+	mce_unregister_decode_chain(&i7_mce_dec);
 
 	/* Disable EDAC polling */
 	i7core_pci_ctl_release(pvt);
@@ -2336,7 +2336,7 @@ static int i7core_register_mci(struct i7core_dev *i7core_dev)
 	/* DCLK for scrub rate setting */
 	pvt->dclk_freq = get_dclk_freq();
 
-	atomic_notifier_chain_register(&x86_mce_decoder_chain, &i7_mce_dec);
+	mce_register_decode_chain(&i7_mce_dec);
 
 	return 0;
 

drivers/edac/mce_amd.c

@@ -884,7 +884,7 @@ static int __init mce_amd_init(void)
 
 	pr_info("MCE: In-kernel MCE decoding enabled.\n");
 
-	atomic_notifier_chain_register(&x86_mce_decoder_chain, &amd_mce_dec_nb);
+	mce_register_decode_chain(&amd_mce_dec_nb);
 
 	return 0;
 }
@@ -893,7 +893,7 @@ early_initcall(mce_amd_init);
 #ifdef MODULE
 static void __exit mce_amd_exit(void)
 {
-	atomic_notifier_chain_unregister(&x86_mce_decoder_chain, &amd_mce_dec_nb);
+	mce_unregister_decode_chain(&amd_mce_dec_nb);
 	kfree(fam_ops);
 }
 

drivers/edac/sb_edac.c

@@ -1661,8 +1661,7 @@ static void sbridge_unregister_mci(struct sbridge_dev *sbridge_dev)
 	debugf0("MC: " __FILE__ ": %s(): mci = %p, dev = %p\n",
 		__func__, mci, &sbridge_dev->pdev[0]->dev);
 
-	atomic_notifier_chain_unregister(&x86_mce_decoder_chain,
-					 &sbridge_mce_dec);
+	mce_unregister_decode_chain(&sbridge_mce_dec);
 
 	/* Remove MC sysfs nodes */
 	edac_mc_del_mc(mci->dev);
@@ -1731,8 +1730,7 @@ static int sbridge_register_mci(struct sbridge_dev *sbridge_dev)
 		goto fail0;
 	}
 
-	atomic_notifier_chain_register(&x86_mce_decoder_chain,
-				       &sbridge_mce_dec);
+	mce_register_decode_chain(&sbridge_mce_dec);
 	return 0;
 
 fail0: