cregit-Linux how code gets into the kernel

Release 4.10 arch/x86/kernel/cpuid.c

Directory: arch/x86/kernel
/* ----------------------------------------------------------------------- *
 *
 *   Copyright 2000-2008 H. Peter Anvin - All Rights Reserved
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
 *   USA; either version 2 of the License, or (at your option) any later
 *   version; incorporated herein by reference.
 *
 * ----------------------------------------------------------------------- */

/*
 * x86 CPUID access device
 *
 * This device is accessed by lseek() to the appropriate CPUID level
 * and then read in chunks of 16 bytes.  A larger size means multiple
 * reads of consecutive levels.
 *
 * The lower 32 bits of the file position is used as the incoming %eax,
 * and the upper 32 bits of the file position as the incoming %ecx,
 * the latter intended for "counting" eax levels like eax=4.
 *
 * This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on
 * an SMP box will direct the access to CPU %d.
 */

#include <linux/module.h>

#include <linux/types.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/smp.h>
#include <linux/major.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/notifier.h>
#include <linux/uaccess.h>
#include <linux/gfp.h>

#include <asm/processor.h>
#include <asm/msr.h>


static struct class *cpuid_class;

static enum cpuhp_state cpuhp_cpuid_state;




static void cpuid_smp_cpuid(void *cmd_block)
{
	struct cpuid_regs *cmd = (struct cpuid_regs *)cmd_block;

	cpuid_count(cmd->eax, cmd->ecx,
		    &cmd->eax, &cmd->ebx, &cmd->ecx, &cmd->edx);
}


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h. peter anvinh. peter anvin1426.42%133.33%


Total53100.00%3100.00%






static ssize_t cpuid_read(struct file *file, char __user *buf,
			  size_t count, loff_t *ppos)
{
	char __user *tmp = buf;
	struct cpuid_regs cmd;
	int cpu = iminor(file_inode(file));
	u64 pos = *ppos;
	ssize_t bytes = 0;
	int err = 0;

	if (count % 16)
		return -EINVAL;	/* Invalid chunk size */

	for (; count; count -= 16) {
		cmd.eax = pos;
		cmd.ecx = pos >> 32;
		err = smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1);
		if (err)
			break;
		if (copy_to_user(tmp, &cmd, 16)) {
			err = -EFAULT;
			break;
		}
		tmp += 16;
		bytes += 16;
		*ppos = ++pos;
	}

	return bytes ? bytes : err;
}


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h. peter anvinh. peter anvin6340.13%342.86%


al viroal viro85.10%342.86%


Total157100.00%7100.00%






static int cpuid_open(struct inode *inode, struct file *file)
{
	unsigned int cpu;
	struct cpuinfo_x86 *c;

	cpu = iminor(file_inode(file));
	if (cpu >= nr_cpu_ids || !cpu_online(cpu))
		return -ENXIO;	/* No such CPU */

	c = &cpu_data(cpu);
	if (c->cpuid_level < 0)
		return -EIO;	/* CPUID not supported */

	return 0;
}


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pre-gitpre-git4255.26%222.22%


jonathan corbetjonathan corbet1722.37%111.11%


andrew mortonandrew morton79.21%222.22%


john kacurjohn kacur56.58%111.11%


al viroal viro45.26%222.22%


mike travismike travis11.32%111.11%


Total76100.00%9100.00%



/*
 * File operations we support
 */

static const struct file_operations cpuid_fops = {
	.owner = THIS_MODULE,
	.llseek = no_seek_end_llseek,
	.read = cpuid_read,
	.open = cpuid_open,
};




static int cpuid_device_create(unsigned int cpu)
{
	struct device *dev;

	dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), NULL,
			    "cpu%d", cpu);
	return PTR_ERR_OR_ZERO(dev);
}


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hanna linderhanna linder2660.47%222.22%


greg kroah-hartmangreg kroah-hartman1023.26%444.44%


akinobu mitaakinobu mita511.63%111.11%


sebastian andrzej siewiorsebastian andrzej siewior12.33%111.11%


fabian frederickfabian frederick12.33%111.11%


Total43100.00%9100.00%






static int cpuid_device_destroy(unsigned int cpu)
{
	device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
	return 0;
}


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akinobu mitaakinobu mita1976.00%133.33%


sebastian andrzej siewiorsebastian andrzej siewior312.00%133.33%


hanna linderhanna linder312.00%133.33%


Total25100.00%3100.00%






static char *cpuid_devnode(struct device *dev, umode_t *mode)
{
	return kasprintf(GFP_KERNEL, "cpu/%u/cpuid", MINOR(dev->devt));
}


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al viroal viro13.23%133.33%


Total31100.00%3100.00%






static int __init cpuid_init(void)
{
	int err;

	if (__register_chrdev(CPUID_MAJOR, 0, NR_CPUS,
			      "cpu/cpuid", &cpuid_fops)) {
		printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
		       CPUID_MAJOR);
		return -EBUSY;
	}
	cpuid_class = class_create(THIS_MODULE, "cpuid");
	if (IS_ERR(cpuid_class)) {
		err = PTR_ERR(cpuid_class);
		goto out_chrdev;
	}
	cpuid_class->devnode = cpuid_devnode;

	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/cpuid:online",
				cpuid_device_create, cpuid_device_destroy);
	if (err < 0)
		goto out_class;

	cpuhp_cpuid_state = err;
	return 0;

out_class:
	class_destroy(cpuid_class);
out_chrdev:
	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
	return err;
}

Contributors
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hanna linderhanna linder6953.91%220.00%


pre-gitpre-git2519.53%110.00%


sebastian andrzej siewiorsebastian andrzej siewior107.81%110.00%


h. peter anvinh. peter anvin107.81%110.00%


kay sieverskay sievers64.69%220.00%


thomas gleixnerthomas gleixner53.91%110.00%


greg kroah-hartmangreg kroah-hartman21.56%110.00%


adrian bunkadrian bunk10.78%110.00%


Total128100.00%10100.00%




module_init(cpuid_init);




static void __exit cpuid_exit(void)
{
	cpuhp_remove_state(cpuhp_cpuid_state);
	class_destroy(cpuid_class);
	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
}

Contributors
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pre-gitpre-git1446.67%222.22%


russ andersonruss anderson516.67%111.11%


hanna linderhanna linder516.67%111.11%


greg kroah-hartmangreg kroah-hartman310.00%222.22%


adrian bunkadrian bunk13.33%111.11%


thomas gleixnerthomas gleixner13.33%111.11%


sebastian andrzej siewiorsebastian andrzej siewior13.33%111.11%


Total30100.00%9100.00%




module_exit(cpuid_exit);

MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
MODULE_DESCRIPTION("x86 generic CPUID driver");
MODULE_LICENSE("GPL");

Overall Contributors
PersonTokensPropCommitsCommitProp
pre-gitpre-git26840.73%37.50%


hanna linderhanna linder11717.78%25.00%


h. peter anvinh. peter anvin8913.53%410.00%


kay sieverskay sievers365.47%25.00%


akinobu mitaakinobu mita243.65%12.50%


jonathan corbetjonathan corbet172.58%12.50%


thomas gleixnerthomas gleixner162.43%12.50%


greg kroah-hartmangreg kroah-hartman162.43%615.00%


sebastian andrzej siewiorsebastian andrzej siewior152.28%12.50%


al viroal viro142.13%512.50%


andrew mortonandrew morton91.37%37.50%


rusty russellrusty russell81.22%12.50%


russ andersonruss anderson50.76%12.50%


john kacurjohn kacur50.76%12.50%


linus torvaldslinus torvalds50.76%12.50%


tejun heotejun heo30.46%12.50%


dave jonesdave jones30.46%12.50%


jaswinder singh rajputjaswinder singh rajput30.46%12.50%


adrian bunkadrian bunk20.30%12.50%


mike travismike travis10.15%12.50%


fabian frederickfabian frederick10.15%12.50%


arjan van de venarjan van de ven10.15%12.50%


Total658100.00%40100.00%


Directory: arch/x86/kernel



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