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Diffstat (limited to 'arch/x86/kernel/cpuid.c')
-rw-r--r--arch/x86/kernel/cpuid.c157
1 files changed, 80 insertions, 77 deletions
diff --git a/arch/x86/kernel/cpuid.c b/arch/x86/kernel/cpuid.c
index 5c2faa10e9f..3225ae6c518 100644
--- a/arch/x86/kernel/cpuid.c
+++ b/arch/x86/kernel/cpuid.c
@@ -1,6 +1,6 @@
/* ----------------------------------------------------------------------- *
- *
- * Copyright 2000 H. Peter Anvin - All Rights Reserved
+ *
+ * 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
@@ -11,14 +11,16 @@
* ----------------------------------------------------------------------- */
/*
- * 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.
*
+ * 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.
*/
@@ -33,63 +35,35 @@
#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 <linux/uaccess.h>
+#include <linux/gfp.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;
+struct cpuid_regs {
+ u32 eax, ebx, ecx, edx;
};
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;
+ struct cpuid_regs *cmd = (struct cpuid_regs *)cmd_block;
- smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1, 1);
- }
- preempt_enable();
+ cpuid_count(cmd->eax, cmd->ecx,
+ &cmd->eax, &cmd->ebx, &cmd->ecx, &cmd->edx);
}
-#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;
+ struct inode *inode = file->f_mapping->host;
- lock_kernel();
-
+ mutex_lock(&inode->i_mutex);
switch (orig) {
case 0:
file->f_pos = offset;
@@ -102,40 +76,51 @@ static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
default:
ret = -EINVAL;
}
-
- unlock_kernel();
+ mutex_unlock(&inode->i_mutex);
return ret;
}
static ssize_t cpuid_read(struct file *file, char __user *buf,
- size_t count, loff_t * ppos)
+ 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);
+ 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) {
- do_cpuid(cpu, reg, data);
- if (copy_to_user(tmp, &data, 16))
- return -EFAULT;
+ 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;
- *ppos = reg++;
+ bytes += 16;
+ *ppos = ++pos;
}
- return tmp - buf;
+ return bytes ? bytes : err;
}
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];
+ unsigned int cpu;
+ struct cpuinfo_x86 *c;
- if (cpu >= NR_CPUS || !cpu_online(cpu))
+ 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 */
@@ -152,45 +137,56 @@ static const struct file_operations cpuid_fops = {
.open = cpuid_open,
};
-static int cpuid_device_create(int i)
+static int cpuid_device_create(int cpu)
{
- 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;
+ dev = device_create(cpuid_class, NULL, MKDEV(CPUID_MAJOR, cpu), NULL,
+ "cpu%d", cpu);
+ return IS_ERR(dev) ? PTR_ERR(dev) : 0;
+}
+
+static void cpuid_device_destroy(int cpu)
+{
+ device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
}
-static int cpuid_class_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+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_ONLINE:
- case CPU_ONLINE_FROZEN:
- cpuid_device_create(cpu);
+ case CPU_UP_PREPARE:
+ err = cpuid_device_create(cpu);
break;
+ case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_FROZEN:
case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
+ cpuid_device_destroy(cpu);
break;
}
- return NOTIFY_OK;
+ return notifier_from_errno(err);
}
-static struct notifier_block __cpuinitdata cpuid_class_cpu_notifier =
+static struct notifier_block __refdata 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));
+}
+
static int __init cpuid_init(void)
{
int i, err = 0;
i = 0;
- if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
+ 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;
@@ -201,12 +197,16 @@ static int __init cpuid_init(void)
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)
+ if (err != 0)
goto out_class;
}
- register_hotcpu_notifier(&cpuid_class_cpu_notifier);
+ __register_hotcpu_notifier(&cpuid_class_cpu_notifier);
+ cpu_notifier_register_done();
err = 0;
goto out;
@@ -214,11 +214,12 @@ static int __init cpuid_init(void)
out_class:
i = 0;
for_each_online_cpu(i) {
- device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, i));
+ cpuid_device_destroy(i);
}
+ cpu_notifier_register_done();
class_destroy(cpuid_class);
out_chrdev:
- unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
+ __unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
out:
return err;
}
@@ -227,11 +228,13 @@ static void __exit cpuid_exit(void)
{
int cpu = 0;
+ cpu_notifier_register_begin();
for_each_online_cpu(cpu)
- device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu));
+ cpuid_device_destroy(cpu);
class_destroy(cpuid_class);
- unregister_chrdev(CPUID_MAJOR, "cpu/cpuid");
- unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
+ __unregister_chrdev(CPUID_MAJOR, 0, NR_CPUS, "cpu/cpuid");
+ __unregister_hotcpu_notifier(&cpuid_class_cpu_notifier);
+ cpu_notifier_register_done();
}
module_init(cpuid_init);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-06 19:14:28 +0000