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(size: 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(addr: 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(to: buf + bytes_read, from: ver_buf, |
81 | n: 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(objp: 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(size: 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(to: ver_buf, from: &buf[bytes_written], |
152 | n: 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(addr: offset, ver: 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(objp: 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(misc: &adi_miscdev); |
226 | } |
227 | |
228 | static void __exit adi_exit(void) |
229 | { |
230 | misc_deregister(misc: &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" ); |
240 | |