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x86/mce: Get rid of register_mce_write_callback()
Make the mcelog call a notifier which lands in the injector module and does the injection. This allows for mce-inject to be a normal kernel module now. Tested-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Yazen Ghannam <yazen.ghannam@amd.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Link: http://lkml.kernel.org/r/20170613162835.30750-5-bp@alien8.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
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parent
bc8e80d56c
commit
fbe9ff9eaf
4 changed files with 62 additions and 63 deletions
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@ -285,10 +285,6 @@ int mce_notify_irq(void);
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DECLARE_PER_CPU(struct mce, injectm);
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extern void register_mce_write_callback(ssize_t (*)(struct file *filp,
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const char __user *ubuf,
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size_t usize, loff_t *off));
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/* Disable CMCI/polling for MCA bank claimed by firmware */
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extern void mce_disable_bank(int bank);
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@ -17,6 +17,8 @@
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#include "mce-internal.h"
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static BLOCKING_NOTIFIER_HEAD(mce_injector_chain);
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static DEFINE_MUTEX(mce_chrdev_read_mutex);
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static char mce_helper[128];
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@ -345,24 +347,49 @@ static long mce_chrdev_ioctl(struct file *f, unsigned int cmd,
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}
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}
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static ssize_t (*mce_write)(struct file *filp, const char __user *ubuf,
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size_t usize, loff_t *off);
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void register_mce_write_callback(ssize_t (*fn)(struct file *filp,
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const char __user *ubuf,
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size_t usize, loff_t *off))
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void mce_register_injector_chain(struct notifier_block *nb)
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{
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mce_write = fn;
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blocking_notifier_chain_register(&mce_injector_chain, nb);
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}
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EXPORT_SYMBOL_GPL(register_mce_write_callback);
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EXPORT_SYMBOL_GPL(mce_register_injector_chain);
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void mce_unregister_injector_chain(struct notifier_block *nb)
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{
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blocking_notifier_chain_unregister(&mce_injector_chain, nb);
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}
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EXPORT_SYMBOL_GPL(mce_unregister_injector_chain);
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static ssize_t mce_chrdev_write(struct file *filp, const char __user *ubuf,
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size_t usize, loff_t *off)
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{
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if (mce_write)
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return mce_write(filp, ubuf, usize, off);
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else
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struct mce m;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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/*
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* There are some cases where real MSR reads could slip
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* through.
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*/
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if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
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return -EIO;
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if ((unsigned long)usize > sizeof(struct mce))
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usize = sizeof(struct mce);
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if (copy_from_user(&m, ubuf, usize))
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return -EFAULT;
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if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
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return -EINVAL;
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/*
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* Need to give user space some time to set everything up,
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* so do it a jiffie or two later everywhere.
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*/
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schedule_timeout(2);
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blocking_notifier_call_chain(&mce_injector_chain, 0, &m);
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return usize;
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}
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static const struct file_operations mce_chrdev_ops = {
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@ -283,42 +283,24 @@ static void __maybe_unused raise_mce(struct mce *m)
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}
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}
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#ifdef CONFIG_X86_MCELOG_LEGACY
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/* Error injection interface */
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static ssize_t mce_write(struct file *filp, const char __user *ubuf,
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size_t usize, loff_t *off)
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static int mce_inject_raise(struct notifier_block *nb, unsigned long val,
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void *data)
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{
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struct mce m;
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struct mce *m = (struct mce *)data;
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if (!capable(CAP_SYS_ADMIN))
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return -EPERM;
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/*
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* There are some cases where real MSR reads could slip
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* through.
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*/
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if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
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return -EIO;
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if ((unsigned long)usize > sizeof(struct mce))
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usize = sizeof(struct mce);
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if (copy_from_user(&m, ubuf, usize))
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return -EFAULT;
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if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
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return -EINVAL;
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/*
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* Need to give user space some time to set everything up,
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* so do it a jiffie or two later everywhere.
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*/
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schedule_timeout(2);
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if (!m)
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return NOTIFY_DONE;
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mutex_lock(&mce_inject_mutex);
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raise_mce(&m);
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raise_mce(m);
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mutex_unlock(&mce_inject_mutex);
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return usize;
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return NOTIFY_DONE;
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}
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#endif /* CONFIG_X86_MCELOG_LEGACY */
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static struct notifier_block inject_nb = {
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.notifier_call = mce_inject_raise,
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};
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/*
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* Caller needs to be make sure this cpu doesn't disappear
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@ -719,44 +701,34 @@ static int __init inject_init(void)
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if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
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return -ENOMEM;
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#ifdef CONFIG_X86_MCELOG_LEGACY
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register_mce_write_callback(mce_write);
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#endif
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register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0, "mce_notify");
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err = debugfs_init();
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if (err) {
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free_cpumask_var(mce_inject_cpumask);
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return err;
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}
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register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0, "mce_notify");
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mce_register_injector_chain(&inject_nb);
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pr_info("Machine check injector initialized\n");
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return 0;
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}
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module_init(inject_init);
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/*
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* Cannot tolerate unloading currently because we cannot
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* guarantee all openers of mce_chrdev will get a reference to us.
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*/
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#ifndef CONFIG_X86_MCELOG_LEGACY
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static void __exit inject_exit(void)
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{
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mce_unregister_injector_chain(&inject_nb);
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unregister_nmi_handler(NMI_LOCAL, "mce_notify");
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debugfs_remove_recursive(dfs_inj);
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dfs_inj = NULL;
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memset(&dfs_fls, 0, sizeof(dfs_fls));
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unregister_nmi_handler(NMI_LOCAL, "mce_notify");
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free_cpumask_var(mce_inject_cpumask);
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}
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module_init(inject_init);
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module_exit(inject_exit);
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#endif
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MODULE_LICENSE("GPL");
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@ -100,7 +100,11 @@ static inline bool mce_cmp(struct mce *m1, struct mce *m2)
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extern struct device_attribute dev_attr_trigger;
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#ifdef CONFIG_X86_MCELOG_LEGACY
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extern void mce_work_trigger(void);
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void mce_work_trigger(void);
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void mce_register_injector_chain(struct notifier_block *nb);
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void mce_unregister_injector_chain(struct notifier_block *nb);
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#else
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static inline void mce_work_trigger(void) { }
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static inline void mce_register_injector_chain(struct notifier_block *nb) { }
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static inline void mce_unregister_injector_chain(struct notifier_block *nb) { }
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#endif
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