patch-2.4.20 linux-2.4.20/arch/x86_64/kernel/msr.c
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- Lines: 275
- Date:
Thu Nov 28 15:53:12 2002
- Orig file:
linux-2.4.19/arch/x86_64/kernel/msr.c
- Orig date:
Wed Dec 31 16:00:00 1969
diff -urN linux-2.4.19/arch/x86_64/kernel/msr.c linux-2.4.20/arch/x86_64/kernel/msr.c
@@ -0,0 +1,274 @@
+#ident "$Id: msr.c,v 1.7 2002/02/14 10:20:47 ak Exp $"
+/* ----------------------------------------------------------------------- *
+ *
+ * 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/major.h>
+
+#include <asm/processor.h>
+#include <asm/msr.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+/* 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"
+ " .quad 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"
+ " .quad 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;
+
+ if ( cpu == smp_processor_id() ) {
+ return 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);
+ return cmd.err;
+ }
+}
+
+static inline int do_rdmsr(int cpu, u32 reg, u32 *eax, u32 *edx)
+{
+ struct msr_command cmd;
+
+ if ( cpu == smp_processor_id() ) {
+ return 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];
+
+ return cmd.err;
+ }
+}
+
+#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)
+{
+ 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 msr_read(struct file * file, char * buf,
+ size_t count, loff_t *ppos)
+{
+ u32 *tmp = (u32 *)buf;
+ u32 data[2];
+ size_t rv;
+ u32 reg = *ppos;
+ int cpu = MINOR(file->f_dentry->d_inode->i_rdev);
+ 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 *)tmp) - buf;
+}
+
+static ssize_t msr_write(struct file * file, const char * buf,
+ size_t count, loff_t *ppos)
+{
+ const u32 *tmp = (const u32 *)buf;
+ u32 data[2];
+ size_t rv;
+ u32 reg = *ppos;
+ int cpu = MINOR(file->f_dentry->d_inode->i_rdev);
+ 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 *)tmp) - buf;
+}
+
+static int msr_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 ( !test_bit(X86_FEATURE_MSR, &c->x86_capability) )
+ 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,
+};
+
+int __init msr_init(void)
+{
+ if (register_chrdev(MSR_MAJOR, "cpu/msr", &msr_fops)) {
+ printk(KERN_ERR "msr: unable to get major %d for msr\n",
+ MSR_MAJOR);
+ return -EBUSY;
+ }
+
+ return 0;
+}
+
+void __exit msr_exit(void)
+{
+ unregister_chrdev(MSR_MAJOR, "cpu/msr");
+}
+
+module_init(msr_init);
+module_exit(msr_exit)
+
+EXPORT_NO_SYMBOLS;
+
+MODULE_AUTHOR("H. Peter Anvin <hpa@zytor.com>");
+MODULE_DESCRIPTION("x86 generic MSR driver");
+MODULE_LICENSE("GPL");
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