patch-2.2.18 linux/arch/i386/kernel/cpuid.c

• Lines: 164
• Date: Thu Oct 19 01:25:23 2000
• Orig file: v2.2.17/arch/i386/kernel/cpuid.c
• Orig date: Thu Jan 1 01:00:00 1970

diff -u --new-file --recursive --exclude-from /usr/src/exclude v2.2.17/arch/i386/kernel/cpuid.c linux/arch/i386/kernel/cpuid.c
@@ -0,0 +1,163 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   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 <asm/processor.h>
+#include <asm/msr.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+#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]);
+}
+
+extern inline void do_cpuid(int cpu, u32 reg, u32 *data)
+{
+  struct cpuid_command cmd;
+  
+  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);
+  }
+}
+#else /* ! CONFIG_SMP */
+
+extern 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)
+{
+  switch (orig) {
+  case 0:
+    file->f_pos = offset;
+    return file->f_pos;
+  case 1:
+    file->f_pos += offset;
+    return file->f_pos;
+  default:
+    return -EINVAL;	/* SEEK_END not supported */
+  }
+}
+
+static ssize_t cpuid_read(struct file * file, char * buf,
+			size_t count, loff_t *ppos)
+{
+  u32 *tmp = (u32 *)buf;
+  u32 data[4];
+  size_t rv;
+  u32 reg = *ppos;
+  int cpu = MINOR(file->f_dentry->d_inode->i_rdev);
+  
+  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 += 4;
+    *ppos = reg++;
+  }
+  
+  return ((char *)tmp) - buf;
+}
+
+static int cpuid_open(struct inode *inode, struct file *file)
+{
+  int cpu = MINOR(file->f_dentry->d_inode->i_rdev);
+  struct cpuinfo_x86 *c = &(cpu_data)[cpu];
+
+  if ( !(cpu_online_map & (1UL << 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 = {
+  llseek:	cpuid_seek,
+  read:		cpuid_read,
+  open:		cpuid_open,
+};
+
+int __init cpuid_init(void)
+{
+  if (register_chrdev(CPUID_MAJOR, "cpu/cpuid", &cpuid_fops)) {
+    printk(KERN_ERR "cpuid: unable to get major %d for cpuid\n",
+	   CPUID_MAJOR);
+    return -EBUSY;
+  }
+
+  return 0;
+}
+
+static void cpuid_exit(void)
+{
+}
+
+module_init(cpuid_init);
+module_exit(cpuid_exit);
+	
+EXPORT_NO_SYMBOLS;
+
+MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
+MODULE_DESCRIPTION("x86 generic CPUID driver");