Bug Summary

File:arch/x86/kernel/cpuid.c
Warning:line 80, column 7
Copies out a struct with untouched element(s): ebx, edx

Annotated Source Code

1/* ----------------------------------------------------------------------- *
2 *
3 * Copyright 2000-2008 H. Peter Anvin - All Rights Reserved
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, Inc., 675 Mass Ave, Cambridge MA 02139,
8 * USA; either version 2 of the License, or (at your option) any later
9 * version; incorporated herein by reference.
10 *
11 * ----------------------------------------------------------------------- */
12
13/*
14 * x86 CPUID access device
15 *
16 * This device is accessed by lseek() to the appropriate CPUID level
17 * and then read in chunks of 16 bytes. A larger size means multiple
18 * reads of consecutive levels.
19 *
20 * The lower 32 bits of the file position is used as the incoming %eax,
21 * and the upper 32 bits of the file position as the incoming %ecx,
22 * the latter intended for "counting" eax levels like eax=4.
23 *
24 * This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on
25 * an SMP box will direct the access to CPU %d.
26 */
27
28#include <linux1/module.h>
29
30#include <linux1/types.h>
31#include <linux1/errno.h>
32#include <linux1/fcntl.h>
33#include <linux1/init.h>
34#include <linux1/poll.h>
35#include <linux1/smp.h>
36#include <linux1/major.h>
37#include <linux1/fs.h>
38#include <linux1/device.h>
39#include <linux1/cpu.h>
40#include <linux1/notifier.h>
41#include <linux1/uaccess.h>
42#include <linux1/gfp.h>
43
44#include <asm/processor.h>
45#include <asm/msr.h>
46
47static struct class *cpuid_class;
48
49struct cpuid_regs {
50 u32 eax, ebx, ecx, edx;
51};
52
53static void cpuid_smp_cpuid(void *cmd_block)
54{
55 struct cpuid_regs *cmd = (struct cpuid_regs *)cmd_block;
56
57 cpuid_count(cmd->eax, cmd->ecx,
58 &cmd->eax, &cmd->ebx, &cmd->ecx, &cmd->edx);
59}
60
61static ssize_t cpuid_read(struct file *file, char __user *buf,
62 size_t count, loff_t *ppos)
63{
64 char __user *tmp = buf;
65 struct cpuid_regs cmd;
66 int cpu = iminor(file_inode(file));
67 u64 pos = *ppos;
68 ssize_t bytes = 0;
69 int err = 0;
70
71 if (count % 16)
1
Taking false branch
→
72 return -EINVAL22; /* Invalid chunk size */
73
74 for (; count; count -= 16) {
2
←
Loop condition is true. Entering loop body
→
75 cmd.eax = pos;
76 cmd.ecx = pos >> 32;
77 err = smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1);
78 if (err)
3
←
Assuming 'err' is 0
→
4
←
Taking false branch
→
79 break;
80 if (copy_to_user(tmp, &cmd, 16)) {
5
←
Copies out a struct with untouched element(s): ebx, edx
81 err = -EFAULT14;
82 break;
83 }
84 tmp += 16;
85 bytes += 16;
86 *ppos = ++pos;
87 }
88
89 return bytes ? bytes : err;
90}
91
92static int cpuid_open(struct inode *inode, struct file *file)
93{
94 unsigned int cpu;
95 struct cpuinfo_x86 *c;
96
97 cpu = iminor(file_inode(file));
98 if (cpu >= nr_cpu_ids || !cpu_online(cpu)cpumask_test_cpu((cpu), ((const struct cpumask *)&__cpu_online_mask
)))
99 return -ENXIO6; /* No such CPU */
100
101 c = &cpu_data(cpu)(*({ do { const void *__vpp_verify = (typeof((&(cpu_info)
) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned
long __ptr; __asm__ ("" : "=r"(__ptr) : "0"((typeof(*((&
(cpu_info)))) *)((&(cpu_info))))); (typeof((typeof(*((&
(cpu_info)))) *)((&(cpu_info))))) (__ptr + (((__per_cpu_offset
[(cpu)])))); }); }));
102 if (c->cpuid_level < 0)
103 return -EIO5; /* CPUID not supported */
104
105 return 0;
106}
107
108/*
109 * File operations we support
110 */
111static const struct file_operations cpuid_fops = {
112 .owner = THIS_MODULE((struct module *)0),
113 .llseek = no_seek_end_llseek,
114 .read = cpuid_read,
115 .open = cpuid_open,
116};
117
118static int cpuid_device_create(int cpu)
119{
120 struct device *dev;
121
122 dev = device_create(cpuid_class, NULL((void *)0), MKDEV(CPUID_MAJOR, cpu)(((203) << 20) | (cpu)), NULL((void *)0),
123 "cpu%d", cpu);
124 return PTR_ERR_OR_ZERO(dev);
125}
126
127static void cpuid_device_destroy(int cpu)
128{
129 device_destroy(cpuid_class, MKDEV(CPUID_MAJOR, cpu)(((203) << 20) | (cpu)));
130}
131
132static int cpuid_class_cpu_callback(struct notifier_block *nfb,
133 unsigned long action, void *hcpu)
134{
135 unsigned int cpu = (unsigned long)hcpu;
136 int err = 0;
137
138 switch (action) {
139 case CPU_UP_PREPARE0x0003:
140 err = cpuid_device_create(cpu);
141 break;
142 case CPU_UP_CANCELED0x0004:
143 case CPU_UP_CANCELED_FROZEN(0x0004 | 0x0010):
144 case CPU_DEAD0x0007:
145 cpuid_device_destroy(cpu);
146 break;
147 }
148 return notifier_from_errno(err);
149}
150
151static struct notifier_block cpuid_class_cpu_notifier =
152{
153 .notifier_call = cpuid_class_cpu_callback,
154};
155
156static char *cpuid_devnode(struct device *dev, umode_t *mode)
157{
158 return kasprintf(GFP_KERNEL((( gfp_t)(0x400000u|0x2000000u)) | (( gfp_t)0x40u) | (( gfp_t
)0x80u)), "cpu/%u/cpuid", MINOR(dev->devt)((unsigned int) ((dev->devt) & ((1U << 20) - 1))
));
159}
160
161static int __init__attribute__ ((__section__(".init.text"))) __attribute__((no_instrument_function
)) cpuid_init(void)
162{
163 int i, err = 0;
164 i = 0;
165
166 if (__register_chrdev(CPUID_MAJOR203, 0, NR_CPUS8192,
167 "cpu/cpuid", &cpuid_fops)) {
168 printk(KERN_ERR"\001" "3" "cpuid: unable to get major %d for cpuid\n",
169 CPUID_MAJOR203);
170 err = -EBUSY16;
171 goto out;
172 }
173 cpuid_class = class_create(THIS_MODULE, "cpuid")({ static struct lock_class_key __key; __class_create(((struct
module *)0), "cpuid", &__key); });
174 if (IS_ERR(cpuid_class)) {
175 err = PTR_ERR(cpuid_class);
176 goto out_chrdev;
177 }
178 cpuid_class->devnode = cpuid_devnode;
179
180 cpu_notifier_register_begincpu_maps_update_begin();
181 for_each_online_cpu(i)for (((i)) = -1; ((i)) = cpumask_next(((i)), (((const struct cpumask
*)&__cpu_online_mask))), ((i)) < nr_cpu_ids;) {
182 err = cpuid_device_create(i);
183 if (err != 0)
184 goto out_class;
185 }
186 __register_hotcpu_notifier(&cpuid_class_cpu_notifier)__register_cpu_notifier(&cpuid_class_cpu_notifier);
187 cpu_notifier_register_donecpu_maps_update_done();
188
189 err = 0;
190 goto out;
191
192out_class:
193 i = 0;
194 for_each_online_cpu(i)for (((i)) = -1; ((i)) = cpumask_next(((i)), (((const struct cpumask
*)&__cpu_online_mask))), ((i)) < nr_cpu_ids;) {
195 cpuid_device_destroy(i);
196 }
197 cpu_notifier_register_donecpu_maps_update_done();
198 class_destroy(cpuid_class);
199out_chrdev:
200 __unregister_chrdev(CPUID_MAJOR203, 0, NR_CPUS8192, "cpu/cpuid");
201out:
202 return err;
203}
204
205static void __exit__attribute__ ((__section__(".exit.text"))) __attribute__((__used__
)) __attribute__((no_instrument_function)) cpuid_exit(void)
206{
207 int cpu = 0;
208
209 cpu_notifier_register_begincpu_maps_update_begin();
210 for_each_online_cpu(cpu)for (((cpu)) = -1; ((cpu)) = cpumask_next(((cpu)), (((const struct
cpumask *)&__cpu_online_mask))), ((cpu)) < nr_cpu_ids
;)
211 cpuid_device_destroy(cpu);
212 class_destroy(cpuid_class);
213 __unregister_chrdev(CPUID_MAJOR203, 0, NR_CPUS8192, "cpu/cpuid");
214 __unregister_hotcpu_notifier(&cpuid_class_cpu_notifier)__unregister_cpu_notifier(&cpuid_class_cpu_notifier);
215 cpu_notifier_register_donecpu_maps_update_done();
216}
217
218module_init(cpuid_init)static initcall_t __initcall_cpuid_init6 __attribute__((__used__
)) __attribute__((__section__(".initcall" "6" ".init"))) = cpuid_init
;;;
219module_exit(cpuid_exit)static exitcall_t __exitcall_cpuid_exit __attribute__((__used__
)) __attribute__ ((__section__(".exitcall.exit"))) = cpuid_exit
;;
220
221MODULE_AUTHOR("H. Peter Anvin <[email protected]>")struct __UNIQUE_ID_author15 {};
222MODULE_DESCRIPTION("x86 generic CPUID driver")struct __UNIQUE_ID_description16 {};
223MODULE_LICENSE("GPL")struct __UNIQUE_ID_license17 {};