cregit-Linux how code gets into the kernel

Release 4.9 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;


struct cpuid_regs {
	



u32 eax, ebx, ecx, edx;
};




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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pre-gitpre-git3973.58%266.67%


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(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 linder2661.90%225.00%


greg kroah-hartmangreg kroah-hartman1023.81%450.00%


akinobu mitaakinobu mita511.90%112.50%


fabian frederickfabian frederick12.38%112.50%


Total42100.00%8100.00%






static void cpuid_device_destroy(int cpu)
{
	device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
}


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akinobu mitaakinobu mita21100.00%1100.00%


Total21100.00%1100.00%






static int cpuid_class_cpu_callback(struct notifier_block *nfb,
				    unsigned long action, void *hcpu)
{
	unsigned int cpu = (unsigned long)hcpu;
	int err = 0;

	switch (action) {
	case CPU_UP_PREPARE:
		err = cpuid_device_create(cpu);
		break;
	case CPU_UP_CANCELED:
	case CPU_UP_CANCELED_FROZEN:
	case CPU_DEAD:
		cpuid_device_destroy(cpu);
		break;
	}
	return notifier_from_errno(err);
}


Contributors
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hanna linderhanna linder4866.67%114.29%


akinobu mitaakinobu mita1520.83%228.57%


rafael j. wysockirafael j. wysocki56.94%228.57%


greg kroah-hartmangreg kroah-hartman45.56%228.57%


Total72100.00%7100.00%




static struct notifier_block cpuid_class_cpu_notifier =
{
	.notifier_call = cpuid_class_cpu_callback,
};




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


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kay sieverskay sievers3096.77%266.67%


al viroal viro13.23%133.33%


Total31100.00%3100.00%






static int __init cpuid_init(void)
{
	int i, err = 0;
	i = 0;

	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);
		err = -EBUSY;
		goto out;
	}
	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;

	cpu_notifier_register_begin();
	for_each_online_cpu(i) {
		err = cpuid_device_create(i);
		if (err != 0)
			goto out_class;
	}
	__register_hotcpu_notifier(&cpuid_class_cpu_notifier);
	cpu_notifier_register_done();

	err = 0;
	goto out;

out_class:
	i = 0;
	for_each_online_cpu(i) {
		cpuid_device_destroy(i);
	}
	cpu_notifier_register_done();
	class_destroy(cpuid_class);
out_chrdev:
	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
out:
	return err;
}


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hanna linderhanna linder10359.88%215.38%


pre-gitpre-git2514.53%17.69%


greg kroah-hartmangreg kroah-hartman169.30%323.08%


h. peter anvinh. peter anvin105.81%17.69%


silas boyd-wickizersilas boyd-wickizer63.49%17.69%


kay sieverskay sievers63.49%215.38%


srivatsa s. bhatsrivatsa s. bhat42.33%17.69%


adrian bunkadrian bunk10.58%17.69%


akinobu mitaakinobu mita10.58%17.69%


Total172100.00%13100.00%






static void __exit cpuid_exit(void)
{
	int cpu = 0;

	cpu_notifier_register_begin();
	for_each_online_cpu(cpu)
		cpuid_device_destroy(cpu);
	class_destroy(cpuid_class);
	__unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
	__unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
	cpu_notifier_register_done();
}


Contributors
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pre-gitpre-git1427.45%218.18%


greg kroah-hartmangreg kroah-hartman1325.49%218.18%


hanna linderhanna linder1019.61%218.18%


russ andersonruss anderson59.80%19.09%


silas boyd-wickizersilas boyd-wickizer47.84%19.09%


srivatsa s. bhatsrivatsa s. bhat35.88%19.09%


adrian bunkadrian bunk11.96%19.09%


akinobu mitaakinobu mita11.96%19.09%


Total51100.00%11100.00%




module_init(cpuid_init);

module_exit(cpuid_exit);

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

Overall Contributors
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pre-gitpre-git27934.40%36.98%


hanna linderhanna linder21326.26%24.65%


h. peter anvinh. peter anvin9711.96%49.30%


greg kroah-hartmangreg kroah-hartman445.43%613.95%


akinobu mitaakinobu mita435.30%24.65%


kay sieverskay sievers364.44%24.65%


jonathan corbetjonathan corbet172.10%12.33%


al viroal viro141.73%511.63%


silas boyd-wickizersilas boyd-wickizer101.23%12.33%


andrew mortonandrew morton91.11%36.98%


rusty russellrusty russell80.99%12.33%


srivatsa s. bhatsrivatsa s. bhat70.86%12.33%


russ andersonruss anderson50.62%12.33%


john kacurjohn kacur50.62%12.33%


linus torvaldslinus torvalds50.62%12.33%


rafael j. wysockirafael j. wysocki50.62%24.65%


jaswinder singh rajputjaswinder singh rajput30.37%12.33%


tejun heotejun heo30.37%12.33%


dave jonesdave jones30.37%12.33%


adrian bunkadrian bunk20.25%12.33%


arjan van de venarjan van de ven10.12%12.33%


fabian frederickfabian frederick10.12%12.33%


mike travismike travis10.12%12.33%


Total811100.00%43100.00%

  
Directory: arch/x86/kernel