devtime.c revision 996 
1/*
2 * Copyright (c) 2004 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <linux/module.h>
30#include <linux/config.h>
31#include <linux/moduleparam.h>
32#include <linux/init.h>
33#include <linux/fs.h>
34#include <asm/uaccess.h>
35#include <linux/kernel.h>
36#include <asm/io.h>
37#include <asm/page.h>
38#include <linux/netdevice.h>
39
40#ifdef __i386__
41#include <asm/processor.h>
42#include <asm/msr.h>
43#endif
44
45#define DRIVER_AUTHOR "Ali Saidi"
46#define DRIVER_DESC   "Interface to time uncacachable read and writes to device registers"
47#define DRIVER_VER    "0.1"
48
49static char *dataAddr = NULL;
50static int count = 0;
51
52static inline uint32_t cycleCounter(uint32_t dep);
53
54static int __init devtime_start(void)
55{
56    uint64_t addr;
57    uint32_t t1, t2;
58    uint32_t trash;
59    int x;
60    uint32_t *times;
61    uint32_t num = 0;
62    struct net_device *dev;
63
64    printk("Devtime Driver Version %s Loaded...\n", DRIVER_VER);
65
66    if (dataAddr != 0 && count != 0) {
67        addr = simple_strtoull(dataAddr, NULL, 0);
68
69        addr = ioremap(addr, PAGE_SIZE);
70        /**
71         * Make sure that the remapping actually worked. On alpha we have
72         * linear addressing, so its not a problem. But it can fail in x86
73         * if physical memory is mapped to this address.
74         */
75        times = kmalloc(sizeof(uint32_t) * count, GFP_USER);
76        if (!times) {
77            printk("Could not allocate memory... Try again later.\n");
78            return -1;
79        }
80
81        if (addr) {
82            printk("Preparing to read %#llx %d times.\n", addr, count);
83
84            t1 = cycleCounter(trash);
85            for (x = 0; x < count; x++) {
86                trash = readl(addr);
87                t2 = cycleCounter(trash);
88                times[num++] = t2 - t1;
89                t1 = t2;
90            }
91
92            /**
93             * Unmap the address.
94             */
95            iounmap(addr);
96
97            printk("Measurements:\n");
98            for (x = 0; x < count; x++) {
99                printk("%d ", times[x]);
100                if (((x + 1) % 10) == 0)
101                    printk("\n");
102            }
103            printk("\nDone.\n");
104        } else {
105            printk("Unable to remap address. Please try again later.\n");
106        }
107    } else {
108        dev = dev_get_by_name("eth0");
109        if (dev) {
110            printk("Eth0: MemStart: %#lx MemEnd: %#lx I/O Addr: %#lx\n",
111                   dev->mem_start, dev->mem_end, dev->base_addr);
112            dev_put(dev);
113        }
114        dev = 0;
115        dev = dev_get_by_name("eth1");
116        if (dev) {
117            printk("Eth1: MemStart: %#lx MemEnd: %#lx I/O Addr: %#lx\n",
118                   dev->mem_start, dev->mem_end, dev->base_addr);
119            dev_put(dev);
120        }
121
122        printk("Required information not supplied.\n");
123    }
124
125    return 0;
126}
127
128#ifdef __i386__
129
130static inline uint32_t cycleCounter(uint32_t dep)
131{
132    uint32_t time;
133    cpuid_eax(0);
134    rdtscl(time);
135    cpuid_eax(0);
136    return time;
137}
138
139#elif __alpha__
140
141inline uint32_t cycleCounter(uint32_t dep)
142{
143    uint32_t res;
144    asm volatile ("rpcc %0, %1" : "=r"(res) : "r" (dep) : "memory");
145    return res;
146}
147#else
148#error Architecture NOT SUPPORTE
149#endif
150
151static void __exit devtime_end(void)
152{
153    printk("Devtime Driver Version %s Unloaded...\n", DRIVER_VER);
154}
155
156
157module_init(devtime_start);
158module_exit(devtime_end);
159
160MODULE_LICENSE("Dual BSD/GPL");
161MODULE_AUTHOR(DRIVER_AUTHOR);
162MODULE_DESCRIPTION(DRIVER_DESC);
163module_param(dataAddr, charp, 0);
164module_param(count, int, 0);
165