From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- arch/i386/kernel/msr.c | 346 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 346 insertions(+) create mode 100644 arch/i386/kernel/msr.c (limited to 'arch/i386/kernel/msr.c') diff --git a/arch/i386/kernel/msr.c b/arch/i386/kernel/msr.c new file mode 100644 index 000000000000..05d9f8f363a6 --- /dev/null +++ b/arch/i386/kernel/msr.c @@ -0,0 +1,346 @@ +/* ----------------------------------------------------------------------- * + * + * 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. + * + * ----------------------------------------------------------------------- */ + +/* + * msr.c + * + * x86 MSR access device + * + * This device is accessed by lseek() to the appropriate register number + * and then read/write in chunks of 8 bytes. A larger size means multiple + * reads or writes of the same register. + * + * This driver uses /dev/cpu/%d/msr where %d is the minor number, and on + * an SMP box will direct the access to CPU %d. + */ + +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +static struct class_simple *msr_class; + +/* Note: "err" is handled in a funny way below. Otherwise one version + of gcc or another breaks. */ + +static inline int wrmsr_eio(u32 reg, u32 eax, u32 edx) +{ + int err; + + asm volatile ("1: wrmsr\n" + "2:\n" + ".section .fixup,\"ax\"\n" + "3: movl %4,%0\n" + " jmp 2b\n" + ".previous\n" + ".section __ex_table,\"a\"\n" + " .align 4\n" " .long 1b,3b\n" ".previous":"=&bDS" (err) + :"a"(eax), "d"(edx), "c"(reg), "i"(-EIO), "0"(0)); + + return err; +} + +static inline int rdmsr_eio(u32 reg, u32 *eax, u32 *edx) +{ + int err; + + asm volatile ("1: rdmsr\n" + "2:\n" + ".section .fixup,\"ax\"\n" + "3: movl %4,%0\n" + " jmp 2b\n" + ".previous\n" + ".section __ex_table,\"a\"\n" + " .align 4\n" + " .long 1b,3b\n" + ".previous":"=&bDS" (err), "=a"(*eax), "=d"(*edx) + :"c"(reg), "i"(-EIO), "0"(0)); + + return err; +} + +#ifdef CONFIG_SMP + +struct msr_command { + int cpu; + int err; + u32 reg; + u32 data[2]; +}; + +static void msr_smp_wrmsr(void *cmd_block) +{ + struct msr_command *cmd = (struct msr_command *)cmd_block; + + if (cmd->cpu == smp_processor_id()) + cmd->err = wrmsr_eio(cmd->reg, cmd->data[0], cmd->data[1]); +} + +static void msr_smp_rdmsr(void *cmd_block) +{ + struct msr_command *cmd = (struct msr_command *)cmd_block; + + if (cmd->cpu == smp_processor_id()) + cmd->err = rdmsr_eio(cmd->reg, &cmd->data[0], &cmd->data[1]); +} + +static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx) +{ + struct msr_command cmd; + int ret; + + preempt_disable(); + if (cpu == smp_processor_id()) { + ret = wrmsr_eio(reg, eax, edx); + } else { + cmd.cpu = cpu; + cmd.reg = reg; + cmd.data[0] = eax; + cmd.data[1] = edx; + + smp_call_function(msr_smp_wrmsr, &cmd, 1, 1); + ret = cmd.err; + } + preempt_enable(); + return ret; +} + +static inline int do_rdmsr(int cpu, u32 reg, u32 * eax, u32 * edx) +{ + struct msr_command cmd; + int ret; + + preempt_disable(); + if (cpu == smp_processor_id()) { + ret = rdmsr_eio(reg, eax, edx); + } else { + cmd.cpu = cpu; + cmd.reg = reg; + + smp_call_function(msr_smp_rdmsr, &cmd, 1, 1); + + *eax = cmd.data[0]; + *edx = cmd.data[1]; + + ret = cmd.err; + } + preempt_enable(); + return ret; +} + +#else /* ! CONFIG_SMP */ + +static inline int do_wrmsr(int cpu, u32 reg, u32 eax, u32 edx) +{ + return wrmsr_eio(reg, eax, edx); +} + +static inline int do_rdmsr(int cpu, u32 reg, u32 *eax, u32 *edx) +{ + return rdmsr_eio(reg, eax, edx); +} + +#endif /* ! CONFIG_SMP */ + +static loff_t msr_seek(struct file *file, loff_t offset, int orig) +{ + loff_t ret = -EINVAL; + + 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; + } + unlock_kernel(); + return ret; +} + +static ssize_t msr_read(struct file *file, char __user * buf, + size_t count, loff_t * ppos) +{ + u32 __user *tmp = (u32 __user *) buf; + u32 data[2]; + size_t rv; + u32 reg = *ppos; + int cpu = iminor(file->f_dentry->d_inode); + int err; + + if (count % 8) + return -EINVAL; /* Invalid chunk size */ + + for (rv = 0; count; count -= 8) { + err = do_rdmsr(cpu, reg, &data[0], &data[1]); + if (err) + return err; + if (copy_to_user(tmp, &data, 8)) + return -EFAULT; + tmp += 2; + } + + return ((char __user *)tmp) - buf; +} + +static ssize_t msr_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + const u32 __user *tmp = (const u32 __user *)buf; + u32 data[2]; + size_t rv; + u32 reg = *ppos; + int cpu = iminor(file->f_dentry->d_inode); + int err; + + if (count % 8) + return -EINVAL; /* Invalid chunk size */ + + for (rv = 0; count; count -= 8) { + if (copy_from_user(&data, tmp, 8)) + return -EFAULT; + err = do_wrmsr(cpu, reg, data[0], data[1]); + if (err) + return err; + tmp += 2; + } + + return ((char __user *)tmp) - buf; +} + +static int msr_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 (!cpu_has(c, X86_FEATURE_MSR)) + return -EIO; /* MSR not supported */ + + return 0; +} + +/* + * File operations we support + */ +static struct file_operations msr_fops = { + .owner = THIS_MODULE, + .llseek = msr_seek, + .read = msr_read, + .write = msr_write, + .open = msr_open, +}; + +static int msr_class_simple_device_add(int i) +{ + int err = 0; + struct class_device *class_err; + + class_err = class_simple_device_add(msr_class, MKDEV(MSR_MAJOR, i), NULL, "msr%d",i); + if (IS_ERR(class_err)) + err = PTR_ERR(class_err); + return err; +} + +static int __devinit msr_class_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) +{ + unsigned int cpu = (unsigned long)hcpu; + + switch (action) { + case CPU_ONLINE: + msr_class_simple_device_add(cpu); + break; + case CPU_DEAD: + class_simple_device_remove(MKDEV(MSR_MAJOR, cpu)); + break; + } + return NOTIFY_OK; +} + +static struct notifier_block msr_class_cpu_notifier = +{ + .notifier_call = msr_class_cpu_callback, +}; + +static int __init msr_init(void) +{ + int i, err = 0; + i = 0; + + if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) { + printk(KERN_ERR "msr: unable to get major %d for msr\n", + MSR_MAJOR); + err = -EBUSY; + goto out; + } + msr_class = class_simple_create(THIS_MODULE, "msr"); + if (IS_ERR(msr_class)) { + err = PTR_ERR(msr_class); + goto out_chrdev; + } + for_each_online_cpu(i) { + err = msr_class_simple_device_add(i); + if (err != 0) + goto out_class; + } + register_cpu_notifier(&msr_class_cpu_notifier); + + err = 0; + goto out; + +out_class: + i = 0; + for_each_online_cpu(i) + class_simple_device_remove(MKDEV(MSR_MAJOR, i)); + class_simple_destroy(msr_class); +out_chrdev: + unregister_chrdev(MSR_MAJOR, "cpu/msr"); +out: + return err; +} + +static void __exit msr_exit(void) +{ + int cpu = 0; + for_each_online_cpu(cpu) + class_simple_device_remove(MKDEV(MSR_MAJOR, cpu)); + class_simple_destroy(msr_class); + unregister_chrdev(MSR_MAJOR, "cpu/msr"); + unregister_cpu_notifier(&msr_class_cpu_notifier); +} + +module_init(msr_init); +module_exit(msr_exit) + +MODULE_AUTHOR("H. Peter Anvin "); +MODULE_DESCRIPTION("x86 generic MSR driver"); +MODULE_LICENSE("GPL"); -- cgit v1.2.1