diff options
Diffstat (limited to 'arch/x86/kernel/cpuid.c')
| -rw-r--r-- | arch/x86/kernel/cpuid.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c new file mode 100644 index 0000000..5c2faa1 --- /dev/null +++ b/arch/x86/kernel/cpuid.c @@ -0,0 +1,242 @@ +/* ----------------------------------------------------------------------- * + * + * Copyright 2000 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. + * + * ----------------------------------------------------------------------- */ + +/* + * cpuid.c + * + * 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. + * + * 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/smp_lock.h> +#include <linux/device.h> +#include <linux/cpu.h> +#include <linux/notifier.h> + +#include <asm/processor.h> +#include <asm/msr.h> +#include <asm/uaccess.h> +#include <asm/system.h> + +static struct class *cpuid_class; + +#ifdef CONFIG_SMP + +struct cpuid_command { + u32 reg; + u32 *data; +}; + +static void cpuid_smp_cpuid(void *cmd_block) +{ + struct cpuid_command *cmd = (struct cpuid_command *)cmd_block; + + cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2], + &cmd->data[3]); +} + +static inline void do_cpuid(int cpu, u32 reg, u32 * data) +{ + struct cpuid_command cmd; + + preempt_disable(); + if (cpu == smp_processor_id()) { + cpuid(reg, &data[0], &data[1], &data[2], &data[3]); + } else { + cmd.reg = reg; + cmd.data = data; + + smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1, 1); + } + preempt_enable(); +} +#else /* ! CONFIG_SMP */ + +static inline void do_cpuid(int cpu, u32 reg, u32 * data) +{ + cpuid(reg, &data[0], &data[1], &data[2], &data[3]); +} + +#endif /* ! CONFIG_SMP */ + +static loff_t cpuid_seek(struct file *file, loff_t offset, int orig) +{ + loff_t ret; + + lock_kernel(); + + switch (orig) { + case 0: + file->f_pos = offset; + ret = file->f_pos; + break; + case 1: + file->f_pos += offset; + ret = file->f_pos; + break; + default: + ret = -EINVAL; + } + + unlock_kernel(); + return ret; +} + +static ssize_t cpuid_read(struct file *file, char __user *buf, + size_t count, loff_t * ppos) +{ + char __user *tmp = buf; + u32 data[4]; + u32 reg = *ppos; + int cpu = iminor(file->f_path.dentry->d_inode); + + if (count % 16) + return -EINVAL; /* Invalid chunk size */ + + for (; count; count -= 16) { + do_cpuid(cpu, reg, data); + if (copy_to_user(tmp, &data, 16)) + return -EFAULT; + tmp += 16; + *ppos = reg++; + } + + return tmp - buf; +} + +static int cpuid_open(struct inode *inode, struct file *file) +{ + unsigned int cpu = iminor(file->f_path.dentry->d_inode); + struct cpuinfo_x86 *c = &(cpu_data)[cpu]; + + if (cpu >= NR_CPUS || !cpu_online(cpu)) + return -ENXIO; /* No such CPU */ + if (c->cpuid_level < 0) + return -EIO; /* CPUID not supported */ + + return 0; +} + +/* + * File operations we support + */ +static const struct file_operations cpuid_fops = { + .owner = THIS_MODULE, + .llseek = cpuid_seek, + .read = cpuid_read, + .open = cpuid_open, +}; + +static int cpuid_device_create(int i) +{ + int err = 0; + struct device *dev; + + dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, i), "cpu%d",i); + if (IS_ERR(dev)) + err = PTR_ERR(dev); + return err; +} + +static int cpuid_class_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) +{ + unsigned int cpu = (unsigned long)hcpu; + + switch (action) { + case CPU_ONLINE: + case CPU_ONLINE_FROZEN: + cpuid_device_create(cpu); + break; + case CPU_DEAD: + case CPU_DEAD_FROZEN: + device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu)); + break; + } + return NOTIFY_OK; +} + +static struct notifier_block __cpuinitdata cpuid_class_cpu_notifier = +{ + .notifier_call = cpuid_class_cpu_callback, +}; + +static int __init cpuid_init(void) +{ + int i, err = 0; + i = 0; + + if (register_chrdev(CPUID_MAJOR, "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; + } + for_each_online_cpu(i) { + err = cpuid_device_create(i); + if (err != 0) + goto out_class; + } + register_hotcpu_notifier(&cpuid_class_cpu_notifier); + + err = 0; + goto out; + +out_class: + i = 0; + for_each_online_cpu(i) { + device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, i)); + } + class_destroy(cpuid_class); +out_chrdev: + unregister_chrdev(CPUID_MAJOR, "cpu/cpuid"); +out: + return err; +} + +static void __exit cpuid_exit(void) +{ + int cpu = 0; + + for_each_online_cpu(cpu) + device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu)); + class_destroy(cpuid_class); + unregister_chrdev(CPUID_MAJOR, "cpu/cpuid"); + unregister_hotcpu_notifier(&cpuid_class_cpu_notifier); +} + +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"); |
