1 files changed, 246 insertions, 0 deletions

diff --git a/arch/i386/kernel/cpuid.c b/arch/i386/kernel/cpuid.c
new file mode 100644
index 000000000000..2e2756345bb2
--- /dev/null
+++ b/arch/i386/kernel/cpuid.c
@@ -0,0 +1,246 @@
+/* ----------------------------------------------------------------------- *
+ *   
+ *   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/config.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/fs.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_simple *cpuid_class;
+
+#ifdef CONFIG_SMP
+
+struct cpuid_command {
+        int cpu;
+        u32 reg;
+        u32 *data;
+};
+
+static void cpuid_smp_cpuid(void *cmd_block)
+{
+        struct cpuid_command *cmd = (struct cpuid_command *)cmd_block;
+
+        if (cmd->cpu == smp_processor_id())
+                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.cpu = cpu;
+                cmd.reg = reg;
+                cmd.data = data;
+
+                smp_call_function(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];
+        size_t rv;
+        u32 reg = *ppos;
+        int cpu = iminor(file->f_dentry->d_inode);
+
+        if (count % 16)
+                return -EINVAL; /* Invalid chunk size */
+
+        for (rv = 0; 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_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 struct file_operations cpuid_fops = {
+        .owner = THIS_MODULE,
+        .llseek = cpuid_seek,
+        .read = cpuid_read,
+        .open = cpuid_open,
+};
+
+static int cpuid_class_simple_device_add(int i) 
+{
+        int err = 0;
+        struct class_device *class_err;
+
+        class_err = class_simple_device_add(cpuid_class, MKDEV(CPUID_MAJOR, i), NULL, "cpu%d",i);
+        if (IS_ERR(class_err))
+                err = PTR_ERR(class_err);
+        return err;
+}
+
+static int __devinit cpuid_class_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+        unsigned int cpu = (unsigned long)hcpu;
+
+        switch (action) {
+        case CPU_ONLINE:
+                cpuid_class_simple_device_add(cpu);
+                break;
+        case CPU_DEAD:
+                class_simple_device_remove(MKDEV(CPUID_MAJOR, cpu));
+                break;
+        }
+        return NOTIFY_OK;
+}
+
+static struct notifier_block 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_simple_create(THIS_MODULE, "cpuid");
+        if (IS_ERR(cpuid_class)) {
+                err = PTR_ERR(cpuid_class);
+                goto out_chrdev;
+        }
+        for_each_online_cpu(i) {
+                err = cpuid_class_simple_device_add(i);
+                if (err != 0) 
+                        goto out_class;
+        }
+        register_cpu_notifier(&cpuid_class_cpu_notifier);
+
+        err = 0;
+        goto out;
+
+out_class:
+        i = 0;
+        for_each_online_cpu(i) {
+                class_simple_device_remove(MKDEV(CPUID_MAJOR, i));
+        }
+        class_simple_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)
+                class_simple_device_remove(MKDEV(CPUID_MAJOR, cpu));
+        class_simple_destroy(cpuid_class);
+        unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
+        unregister_cpu_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");