4 files changed, 61 insertions, 62 deletions

diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 3f9a3d2a5209..181264989db5 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -285,10 +285,6 @@ int mce_notify_irq(void);
 
 DECLARE_PER_CPU(struct mce, injectm);
 
-extern void register_mce_write_callback(ssize_t (*)(struct file *filp,
-                                    const char __user *ubuf,
-                                    size_t usize, loff_t *off));
-
 /* Disable CMCI/polling for MCA bank claimed by firmware */
 extern void mce_disable_bank(int bank);
 
diff --git a/arch/x86/kernel/cpu/mcheck/dev-mcelog.c b/arch/x86/kernel/cpu/mcheck/dev-mcelog.c
index 9c632cb88546..a80427c30c93 100644
--- a/arch/x86/kernel/cpu/mcheck/dev-mcelog.c
+++ b/arch/x86/kernel/cpu/mcheck/dev-mcelog.c
@@ -17,6 +17,8 @@
 
 #include "mce-internal.h"
 
+static BLOCKING_NOTIFIER_HEAD(mce_injector_chain);
+
 static DEFINE_MUTEX(mce_chrdev_read_mutex);
 
 static char mce_helper[128];
@@ -345,24 +347,49 @@ static long mce_chrdev_ioctl(struct file *f, unsigned int cmd,
         }
 }
 
-static ssize_t (*mce_write)(struct file *filp, const char __user *ubuf,
-                            size_t usize, loff_t *off);
+void mce_register_injector_chain(struct notifier_block *nb)
+{
+        blocking_notifier_chain_register(&mce_injector_chain, nb);
+}
+EXPORT_SYMBOL_GPL(mce_register_injector_chain);
 
-void register_mce_write_callback(ssize_t (*fn)(struct file *filp,
-                             const char __user *ubuf,
-                             size_t usize, loff_t *off))
+void mce_unregister_injector_chain(struct notifier_block *nb)
 {
-        mce_write = fn;
+        blocking_notifier_chain_unregister(&mce_injector_chain, nb);
 }
-EXPORT_SYMBOL_GPL(register_mce_write_callback);
+EXPORT_SYMBOL_GPL(mce_unregister_injector_chain);
 
 static ssize_t mce_chrdev_write(struct file *filp, const char __user *ubuf,
                                 size_t usize, loff_t *off)
 {
-        if (mce_write)
-                return mce_write(filp, ubuf, usize, off);
-        else
+        struct mce m;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EPERM;
+        /*
+         * There are some cases where real MSR reads could slip
+         * through.
+         */
+        if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
+                return -EIO;
+
+        if ((unsigned long)usize > sizeof(struct mce))
+                usize = sizeof(struct mce);
+        if (copy_from_user(&m, ubuf, usize))
+                return -EFAULT;
+
+        if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
                 return -EINVAL;
+
+        /*
+         * Need to give user space some time to set everything up,
+         * so do it a jiffie or two later everywhere.
+         */
+        schedule_timeout(2);
+
+        blocking_notifier_call_chain(&mce_injector_chain, 0, &m);
+
+        return usize;
 }
 
 static const struct file_operations mce_chrdev_ops = {
diff --git a/arch/x86/kernel/cpu/mcheck/mce-inject.c b/arch/x86/kernel/cpu/mcheck/mce-inject.c
index 7170186938e5..c21c1a73712a 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-inject.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-inject.c
@@ -283,42 +283,24 @@ static void __maybe_unused raise_mce(struct mce *m)
         }
 }
 
-#ifdef CONFIG_X86_MCELOG_LEGACY
-/* Error injection interface */
-static ssize_t mce_write(struct file *filp, const char __user *ubuf,
-                         size_t usize, loff_t *off)
+static int mce_inject_raise(struct notifier_block *nb, unsigned long val,
+                            void *data)
 {
-        struct mce m;
-
-        if (!capable(CAP_SYS_ADMIN))
-                return -EPERM;
-        /*
-         * There are some cases where real MSR reads could slip
-         * through.
-         */
-        if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
-                return -EIO;
-
-        if ((unsigned long)usize > sizeof(struct mce))
-                usize = sizeof(struct mce);
-        if (copy_from_user(&m, ubuf, usize))
-                return -EFAULT;
-
-        if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
-                return -EINVAL;
+        struct mce *m = (struct mce *)data;
 
-        /*
-         * Need to give user space some time to set everything up,
-         * so do it a jiffie or two later everywhere.
-         */
-        schedule_timeout(2);
+        if (!m)
+                return NOTIFY_DONE;
 
         mutex_lock(&mce_inject_mutex);
-        raise_mce(&m);
+        raise_mce(m);
         mutex_unlock(&mce_inject_mutex);
-        return usize;
+
+        return NOTIFY_DONE;
 }
-#endif /* CONFIG_X86_MCELOG_LEGACY */
+
+static struct notifier_block inject_nb = {
+        .notifier_call  = mce_inject_raise,
+};
 
 /*
  * Caller needs to be make sure this cpu doesn't disappear
@@ -719,44 +701,34 @@ static int __init inject_init(void)
         if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
                 return -ENOMEM;
 
-#ifdef CONFIG_X86_MCELOG_LEGACY
-                register_mce_write_callback(mce_write);
-#endif
-
-        register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0, "mce_notify");
-
         err = debugfs_init();
         if (err) {
                 free_cpumask_var(mce_inject_cpumask);
                 return err;
         }
 
+        register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0, "mce_notify");
+        mce_register_injector_chain(&inject_nb);
+
         pr_info("Machine check injector initialized\n");
 
         return 0;
 }
 
-module_init(inject_init);
-
-/*
- * Cannot tolerate unloading currently because we cannot
- * guarantee all openers of mce_chrdev will get a reference to us.
- */
-#ifndef CONFIG_X86_MCELOG_LEGACY
 static void __exit inject_exit(void)
 {
 
+        mce_unregister_injector_chain(&inject_nb);
+        unregister_nmi_handler(NMI_LOCAL, "mce_notify");
+
         debugfs_remove_recursive(dfs_inj);
         dfs_inj = NULL;
 
         memset(&dfs_fls, 0, sizeof(dfs_fls));
 
-        unregister_nmi_handler(NMI_LOCAL, "mce_notify");
-
         free_cpumask_var(mce_inject_cpumask);
 }
 
+module_init(inject_init);
 module_exit(inject_exit);
-#endif
-
 MODULE_LICENSE("GPL");
diff --git a/arch/x86/kernel/cpu/mcheck/mce-internal.h b/arch/x86/kernel/cpu/mcheck/mce-internal.h
index 654ad0668d72..098530a93bb7 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-internal.h
+++ b/arch/x86/kernel/cpu/mcheck/mce-internal.h
@@ -100,7 +100,11 @@ static inline bool mce_cmp(struct mce *m1, struct mce *m2)
 extern struct device_attribute dev_attr_trigger;
 
 #ifdef CONFIG_X86_MCELOG_LEGACY
-extern void mce_work_trigger(void);
+void mce_work_trigger(void);
+void mce_register_injector_chain(struct notifier_block *nb);
+void mce_unregister_injector_chain(struct notifier_block *nb);
 #else
 static inline void mce_work_trigger(void)       { }
+static inline void mce_register_injector_chain(struct notifier_block *nb)       { }
+static inline void mce_unregister_injector_chain(struct notifier_block *nb)     { }
 #endif