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1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Privileged ADI driver for sparc64 | |
4 | * | |
5 | * Author: Tom Hromatka <tom.hromatka@oracle.com> | |
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 | ||
17 | static int adi_open(struct inode *inode, struct file *file) | |
18 | { | |
19 | file->f_mode |= FMODE_UNSIGNED_OFFSET; | |
20 | return 0; | |
21 | } | |
22 | ||
23 | static 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 | ||
54 | static 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; | |
96 | out: | |
97 | kfree(ver_buf); | |
98 | return ret; | |
99 | } | |
100 | ||
101 | static 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 | ||
131 | static 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; | |
171 | out: | |
172 | __asm__ __volatile__("membar #Sync"); | |
173 | kfree(ver_buf); | |
174 | return ret; | |
175 | } | |
176 | ||
177 | static 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 | /* unsupported */ | |
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 | ||
206 | static 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 | ||
214 | static struct miscdevice adi_miscdev = { | |
215 | .minor = MISC_DYNAMIC_MINOR, | |
216 | .name = KBUILD_MODNAME, | |
217 | .fops = &adi_fops, | |
218 | }; | |
219 | ||
220 | static int __init adi_init(void) | |
221 | { | |
222 | if (!adi_capable()) | |
223 | return -EPERM; | |
224 | ||
225 | return misc_register(&adi_miscdev); | |
226 | } | |
227 | ||
228 | static void __exit adi_exit(void) | |
229 | { | |
230 | misc_deregister(&adi_miscdev); | |
231 | } | |
232 | ||
233 | module_init(adi_init); | |
234 | module_exit(adi_exit); | |
235 | ||
236 | MODULE_AUTHOR("Tom Hromatka <tom.hromatka@oracle.com>"); | |
237 | MODULE_DESCRIPTION("Privileged interface to ADI"); | |
238 | MODULE_VERSION("1.0"); | |
239 | MODULE_LICENSE("GPL v2"); |