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x86/mce: Get rid of register_mce_write_callback()

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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>
This commit is contained in:
Borislav Petkov 2017-06-13 18:28:31 +02:00 committed by Ingo Molnar
parent bc8e80d56c
commit fbe9ff9eaf
4 changed files with 62 additions and 63 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/x86/include/asm/mce.h
View File

@ -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);

49
arch/x86/kernel/cpu/mcheck/dev-mcelog.c
View File

@ -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 register_mce_write_callback(ssize_t (*fn)(struct file *filp,
const char __user *ubuf,
size_t usize, loff_t *off))
void mce_register_injector_chain(struct notifier_block *nb)
{
mce_write = fn;
blocking_notifier_chain_register(&mce_injector_chain, nb);
}
EXPORT_SYMBOL_GPL(register_mce_write_callback);
EXPORT_SYMBOL_GPL(mce_register_injector_chain);
void mce_unregister_injector_chain(struct notifier_block *nb)
{
blocking_notifier_chain_unregister(&mce_injector_chain, nb);
}
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 = {

66
arch/x86/kernel/cpu/mcheck/mce-inject.c
View File

@ -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;
struct mce *m = (struct mce *)data;
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);
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");

6
arch/x86/kernel/cpu/mcheck/mce-internal.h
View File

@ -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