Commit 5b87c058 authored by Ivan Orlov's avatar Ivan Orlov Committed by Greg Kroah-Hartman
Browse files

x86/MSR: make msr_class a static const structure 



Now that the driver core allows for struct class to be in read-only
memory, move the msr_class structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at boot time.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Suggested-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarIvan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20230620144431.583290-5-gregkh@linuxfoundation.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f4a5fbfa

arch/x86/kernel/msr.c

+16 −15
Original line number Diff line number Diff line
@@ -39,7 +39,6 @@ 
#include <asm/cpufeature.h>

#include <asm/msr.h>



static struct class *msr_class;

static enum cpuhp_state cpuhp_msr_state;



enum allow_write_msrs {
@@ -235,26 +234,31 @@ static const struct file_operations msr_fops = { 
	.compat_ioctl = msr_ioctl,

};



static char *msr_devnode(const struct device *dev, umode_t *mode)

{

	return kasprintf(GFP_KERNEL, "cpu/%u/msr", MINOR(dev->devt));

}



static const struct class msr_class = {

	.name		= "msr",

	.devnode	= msr_devnode,

};



static int msr_device_create(unsigned int cpu)

{

	struct device *dev;



	dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, cpu), NULL,

	dev = device_create(&msr_class, NULL, MKDEV(MSR_MAJOR, cpu), NULL,

			    "msr%d", cpu);

	return PTR_ERR_OR_ZERO(dev);

}



static int msr_device_destroy(unsigned int cpu)

{

	device_destroy(msr_class, MKDEV(MSR_MAJOR, cpu));

	device_destroy(&msr_class, MKDEV(MSR_MAJOR, cpu));

	return 0;

}



static char *msr_devnode(const struct device *dev, umode_t *mode)

{

	return kasprintf(GFP_KERNEL, "cpu/%u/msr", MINOR(dev->devt));

}



static int __init msr_init(void)

{

	int err;
@@ -263,12 +267,9 @@ static int __init msr_init(void) 
		pr_err("unable to get major %d for msr\n", MSR_MAJOR);

		return -EBUSY;

	}

	msr_class = class_create("msr");

	if (IS_ERR(msr_class)) {

		err = PTR_ERR(msr_class);

	err = class_register(&msr_class);

	if (err)

		goto out_chrdev;

	}

	msr_class->devnode = msr_devnode;



	err  = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/msr:online",

				 msr_device_create, msr_device_destroy);
@@ -278,7 +279,7 @@ static int __init msr_init(void) 
	return 0;



out_class:

	class_destroy(msr_class);

	class_unregister(&msr_class);

out_chrdev:

	__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");

	return err;
@@ -288,7 +289,7 @@ module_init(msr_init); 
static void __exit msr_exit(void)

{

	cpuhp_remove_state(cpuhp_msr_state);

	class_destroy(msr_class);

	class_unregister(&msr_class);

	__unregister_chrdev(MSR_MAJOR, 0, NR_CPUS, "cpu/msr");

}

module_exit(msr_exit)