Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 66f5ddf3 authored by Tony Luck's avatar Tony Luck Committed by Ingo Molnar
Browse files

x86/mce: Make mce_chrdev_ops 'static const' 



Arjan would like to make struct file_operations const, but
mce-inject directly writes to the mce_chrdev_ops to install its
write handler. In an ideal world mce-inject would have its own
character device, but we have a sizable legacy of test scripts
that hardwire "/dev/mcelog", so it would be painful to switch to
a separate device now. Instead, this patch switches to a stub
function in the mce code, with a registration helper that
mce-inject can call when it is loaded.

Note that this would also allow for a sane process to allow
mce-inject to be unloaded again (with an unregister function,
and appropriate module_{get,put}() calls), but that is left for
potential future patches.

Reported-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/4eb2e1971326651a3b@agluck-desktop.sc.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 1ea6b8f4

arch/x86/include/asm/mce.h

+4 −1
Original line number Diff line number Diff line
@@ -201,7 +201,10 @@ int mce_notify_irq(void); 
void mce_notify_process(void);



DECLARE_PER_CPU(struct mce, injectm);

extern struct file_operations mce_chrdev_ops;



extern void register_mce_write_callback(ssize_t (*)(struct file *filp,

				    const char __user *ubuf,

				    size_t usize, loff_t *off));



/*

 * Exception handler

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

+1 −1
Original line number Diff line number Diff line
@@ -208,7 +208,7 @@ static int inject_init(void) 
	if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))

		return -ENOMEM;

	printk(KERN_INFO "Machine check injector initialized\n");

	mce_chrdev_ops.write = mce_write;

	register_mce_write_callback(mce_write);

	register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0,

				"mce_notify");

	return 0;

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

+22 −3
Original line number Diff line number Diff line
@@ -1634,16 +1634,35 @@ static long mce_chrdev_ioctl(struct file *f, unsigned int cmd, 
	}

}



/* Modified in mce-inject.c, so not static or const */

struct file_operations mce_chrdev_ops = {

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))

{

	mce_write = fn;

}

EXPORT_SYMBOL_GPL(register_mce_write_callback);



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

		return -EINVAL;

}



static const struct file_operations mce_chrdev_ops = {

	.open			= mce_chrdev_open,

	.release		= mce_chrdev_release,

	.read			= mce_chrdev_read,

	.write			= mce_chrdev_write,

	.poll			= mce_chrdev_poll,

	.unlocked_ioctl		= mce_chrdev_ioctl,

	.llseek			= no_llseek,

};

EXPORT_SYMBOL_GPL(mce_chrdev_ops);



static struct miscdevice mce_chrdev_device = {

	MISC_MCELOG_MINOR,