1
2
3
4
5
6
7#include <linux/kernel.h>
8#include <linux/miscdevice.h>
9#include <linux/module.h>
10#include <linux/proc_fs.h>
11#include <linux/slab.h>
12#include <linux/uaccess.h>
13#include <asm/asi.h>
14
15#define MAX_BUF_SZ PAGE_SIZE
16
17static int adi_open(struct inode *inode, struct file *file)
18{
19 file->f_mode |= FMODE_UNSIGNED_OFFSET;
20 return 0;
21}
22
23static int read_mcd_tag(unsigned long addr)
24{
25 long err;
26 int ver;
27
28 __asm__ __volatile__(
29 "1: ldxa [%[addr]] %[asi], %[ver]\n"
30 " mov 0, %[err]\n"
31 "2:\n"
32 " .section .fixup,#alloc,#execinstr\n"
33 " .align 4\n"
34 "3: sethi %%hi(2b), %%g1\n"
35 " jmpl %%g1 + %%lo(2b), %%g0\n"
36 " mov %[invalid], %[err]\n"
37 " .previous\n"
38 " .section __ex_table, \"a\"\n"
39 " .align 4\n"
40 " .word 1b, 3b\n"
41 " .previous\n"
42 : [ver] "=r" (ver), [err] "=r" (err)
43 : [addr] "r" (addr), [invalid] "i" (EFAULT),
44 [asi] "i" (ASI_MCD_REAL)
45 : "memory", "g1"
46 );
47
48 if (err)
49 return -EFAULT;
50 else
51 return ver;
52}
53
54static ssize_t adi_read(struct file *file, char __user *buf,
55 size_t count, loff_t *offp)
56{
57 size_t ver_buf_sz, bytes_read = 0;
58 int ver_buf_idx = 0;
59 loff_t offset;
60 u8 *ver_buf;
61 ssize_t ret;
62
63 ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);
64 ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);
65 if (!ver_buf)
66 return -ENOMEM;
67
68 offset = (*offp) * adi_blksize();
69
70 while (bytes_read < count) {
71 ret = read_mcd_tag(offset);
72 if (ret < 0)
73 goto out;
74
75 ver_buf[ver_buf_idx] = (u8)ret;
76 ver_buf_idx++;
77 offset += adi_blksize();
78
79 if (ver_buf_idx >= ver_buf_sz) {
80 if (copy_to_user(buf + bytes_read, ver_buf,
81 ver_buf_sz)) {
82 ret = -EFAULT;
83 goto out;
84 }
85
86 bytes_read += ver_buf_sz;
87 ver_buf_idx = 0;
88
89 ver_buf_sz = min(count - bytes_read,
90 (size_t)MAX_BUF_SZ);
91 }
92 }
93
94 (*offp) += bytes_read;
95 ret = bytes_read;
96out:
97 kfree(ver_buf);
98 return ret;
99}
100
101static int set_mcd_tag(unsigned long addr, u8 ver)
102{
103 long err;
104
105 __asm__ __volatile__(
106 "1: stxa %[ver], [%[addr]] %[asi]\n"
107 " mov 0, %[err]\n"
108 "2:\n"
109 " .section .fixup,#alloc,#execinstr\n"
110 " .align 4\n"
111 "3: sethi %%hi(2b), %%g1\n"
112 " jmpl %%g1 + %%lo(2b), %%g0\n"
113 " mov %[invalid], %[err]\n"
114 " .previous\n"
115 " .section __ex_table, \"a\"\n"
116 " .align 4\n"
117 " .word 1b, 3b\n"
118 " .previous\n"
119 : [err] "=r" (err)
120 : [ver] "r" (ver), [addr] "r" (addr),
121 [invalid] "i" (EFAULT), [asi] "i" (ASI_MCD_REAL)
122 : "memory", "g1"
123 );
124
125 if (err)
126 return -EFAULT;
127 else
128 return ver;
129}
130
131static ssize_t adi_write(struct file *file, const char __user *buf,
132 size_t count, loff_t *offp)
133{
134 size_t ver_buf_sz, bytes_written = 0;
135 loff_t offset;
136 u8 *ver_buf;
137 ssize_t ret;
138 int i;
139
140 if (count <= 0)
141 return -EINVAL;
142
143 ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);
144 ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);
145 if (!ver_buf)
146 return -ENOMEM;
147
148 offset = (*offp) * adi_blksize();
149
150 do {
151 if (copy_from_user(ver_buf, &buf[bytes_written],
152 ver_buf_sz)) {
153 ret = -EFAULT;
154 goto out;
155 }
156
157 for (i = 0; i < ver_buf_sz; i++) {
158 ret = set_mcd_tag(offset, ver_buf[i]);
159 if (ret < 0)
160 goto out;
161
162 offset += adi_blksize();
163 }
164
165 bytes_written += ver_buf_sz;
166 ver_buf_sz = min(count - bytes_written, (size_t)MAX_BUF_SZ);
167 } while (bytes_written < count);
168
169 (*offp) += bytes_written;
170 ret = bytes_written;
171out:
172 __asm__ __volatile__("membar #Sync");
173 kfree(ver_buf);
174 return ret;
175}
176
177static loff_t adi_llseek(struct file *file, loff_t offset, int whence)
178{
179 loff_t ret = -EINVAL;
180
181 switch (whence) {
182 case SEEK_END:
183 case SEEK_DATA:
184 case SEEK_HOLE:
185
186 return -EINVAL;
187 case SEEK_CUR:
188 if (offset == 0)
189 return file->f_pos;
190
191 offset += file->f_pos;
192 break;
193 case SEEK_SET:
194 break;
195 }
196
197 if (offset != file->f_pos) {
198 file->f_pos = offset;
199 file->f_version = 0;
200 ret = offset;
201 }
202
203 return ret;
204}
205
206static const struct file_operations adi_fops = {
207 .owner = THIS_MODULE,
208 .llseek = adi_llseek,
209 .open = adi_open,
210 .read = adi_read,
211 .write = adi_write,
212};
213
214static struct miscdevice adi_miscdev = {
215 .minor = MISC_DYNAMIC_MINOR,
216 .name = KBUILD_MODNAME,
217 .fops = &adi_fops,
218};
219
220static int __init adi_init(void)
221{
222 if (!adi_capable())
223 return -EPERM;
224
225 return misc_register(&adi_miscdev);
226}
227
228static void __exit adi_exit(void)
229{
230 misc_deregister(&adi_miscdev);
231}
232
233module_init(adi_init);
234module_exit(adi_exit);
235
236MODULE_AUTHOR("Tom Hromatka <tom.hromatka@oracle.com>");
237MODULE_DESCRIPTION("Privileged interface to ADI");
238MODULE_VERSION("1.0");
239MODULE_LICENSE("GPL v2");
240
