diff options
Diffstat (limited to 'arch/i386/kernel/cpuid.c')
-rw-r--r-- | arch/i386/kernel/cpuid.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/arch/i386/kernel/cpuid.c b/arch/i386/kernel/cpuid.c new file mode 100644 index 000000000..34c34d818 --- /dev/null +++ b/arch/i386/kernel/cpuid.c @@ -0,0 +1,168 @@ +#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, (void *)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); + + if ( !(cpu_online_map & (1UL << cpu)) ) + return -ENXIO; /* No such CPU */ + + MOD_INC_USE_COUNT; + return 0; +} + +static int cpuid_release(struct inode *inode, struct file *file) +{ + MOD_DEC_USE_COUNT; + return 0; +} + +/* + * File operations we support + */ +static struct file_operations cpuid_fops = { + llseek: cpuid_seek, + read: cpuid_read, + open: cpuid_open, + release: cpuid_release, +}; + +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; +} + +void __exit 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"); |