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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/kernel/msr.c
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-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!
Diffstat (limited to 'arch/i386/kernel/msr.c')
-rw-r--r--arch/i386/kernel/msr.c346
1 files changed, 346 insertions, 0 deletions
diff --git a/arch/i386/kernel/msr.c b/arch/i386/kernel/msr.c
new file mode 100644
index 00000000000..05d9f8f363a
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+++ b/arch/i386/kernel/msr.c
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+/* ----------------------------------------------------------------------- *
+ *
+ * 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 <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/smp_lock.h>
+#include <linux/major.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 *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 <hpa@zytor.com>");
+MODULE_DESCRIPTION("x86 generic MSR driver");
+MODULE_LICENSE("GPL");