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Merge tag 'drm/tegra/for-5.7-fixes' of git://anongit.freedesktop.org/tegra/linux...
[thirdparty/linux.git] / arch / s390 / lib / uaccess.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Standard user space access functions based on mvcp/mvcs and doing
4 * interesting things in the secondary space mode.
5 *
6 * Copyright IBM Corp. 2006,2014
7 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
8 * Gerald Schaefer (gerald.schaefer@de.ibm.com)
9 */
10
11 #include <linux/jump_label.h>
12 #include <linux/uaccess.h>
13 #include <linux/export.h>
14 #include <linux/errno.h>
15 #include <linux/mm.h>
16 #include <asm/mmu_context.h>
17 #include <asm/facility.h>
18
19 #ifndef CONFIG_HAVE_MARCH_Z10_FEATURES
20 static DEFINE_STATIC_KEY_FALSE(have_mvcos);
21
22 static int __init uaccess_init(void)
23 {
24 if (test_facility(27))
25 static_branch_enable(&have_mvcos);
26 return 0;
27 }
28 early_initcall(uaccess_init);
29
30 static inline int copy_with_mvcos(void)
31 {
32 if (static_branch_likely(&have_mvcos))
33 return 1;
34 return 0;
35 }
36 #else
37 static inline int copy_with_mvcos(void)
38 {
39 return 1;
40 }
41 #endif
42
43 void set_fs(mm_segment_t fs)
44 {
45 current->thread.mm_segment = fs;
46 if (fs == USER_DS) {
47 __ctl_load(S390_lowcore.user_asce, 1, 1);
48 clear_cpu_flag(CIF_ASCE_PRIMARY);
49 } else {
50 __ctl_load(S390_lowcore.kernel_asce, 1, 1);
51 set_cpu_flag(CIF_ASCE_PRIMARY);
52 }
53 if (fs & 1) {
54 if (fs == USER_DS_SACF)
55 __ctl_load(S390_lowcore.user_asce, 7, 7);
56 else
57 __ctl_load(S390_lowcore.kernel_asce, 7, 7);
58 set_cpu_flag(CIF_ASCE_SECONDARY);
59 }
60 }
61 EXPORT_SYMBOL(set_fs);
62
63 mm_segment_t enable_sacf_uaccess(void)
64 {
65 mm_segment_t old_fs;
66 unsigned long asce, cr;
67 unsigned long flags;
68
69 old_fs = current->thread.mm_segment;
70 if (old_fs & 1)
71 return old_fs;
72 /* protect against a concurrent page table upgrade */
73 local_irq_save(flags);
74 current->thread.mm_segment |= 1;
75 asce = S390_lowcore.kernel_asce;
76 if (likely(old_fs == USER_DS)) {
77 __ctl_store(cr, 1, 1);
78 if (cr != S390_lowcore.kernel_asce) {
79 __ctl_load(S390_lowcore.kernel_asce, 1, 1);
80 set_cpu_flag(CIF_ASCE_PRIMARY);
81 }
82 asce = S390_lowcore.user_asce;
83 }
84 __ctl_store(cr, 7, 7);
85 if (cr != asce) {
86 __ctl_load(asce, 7, 7);
87 set_cpu_flag(CIF_ASCE_SECONDARY);
88 }
89 local_irq_restore(flags);
90 return old_fs;
91 }
92 EXPORT_SYMBOL(enable_sacf_uaccess);
93
94 void disable_sacf_uaccess(mm_segment_t old_fs)
95 {
96 current->thread.mm_segment = old_fs;
97 if (old_fs == USER_DS && test_facility(27)) {
98 __ctl_load(S390_lowcore.user_asce, 1, 1);
99 clear_cpu_flag(CIF_ASCE_PRIMARY);
100 }
101 }
102 EXPORT_SYMBOL(disable_sacf_uaccess);
103
104 static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
105 unsigned long size)
106 {
107 register unsigned long reg0 asm("0") = 0x01UL;
108 unsigned long tmp1, tmp2;
109
110 tmp1 = -4096UL;
111 asm volatile(
112 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
113 "6: jz 4f\n"
114 "1: algr %0,%3\n"
115 " slgr %1,%3\n"
116 " slgr %2,%3\n"
117 " j 0b\n"
118 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
119 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
120 " slgr %4,%1\n"
121 " clgr %0,%4\n" /* copy crosses next page boundary? */
122 " jnh 5f\n"
123 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
124 "7: slgr %0,%4\n"
125 " j 5f\n"
126 "4: slgr %0,%0\n"
127 "5:\n"
128 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
129 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
130 : "d" (reg0) : "cc", "memory");
131 return size;
132 }
133
134 static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
135 unsigned long size)
136 {
137 unsigned long tmp1, tmp2;
138 mm_segment_t old_fs;
139
140 old_fs = enable_sacf_uaccess();
141 tmp1 = -256UL;
142 asm volatile(
143 " sacf 0\n"
144 "0: mvcp 0(%0,%2),0(%1),%3\n"
145 "7: jz 5f\n"
146 "1: algr %0,%3\n"
147 " la %1,256(%1)\n"
148 " la %2,256(%2)\n"
149 "2: mvcp 0(%0,%2),0(%1),%3\n"
150 "8: jnz 1b\n"
151 " j 5f\n"
152 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
153 " lghi %3,-4096\n"
154 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
155 " slgr %4,%1\n"
156 " clgr %0,%4\n" /* copy crosses next page boundary? */
157 " jnh 6f\n"
158 "4: mvcp 0(%4,%2),0(%1),%3\n"
159 "9: slgr %0,%4\n"
160 " j 6f\n"
161 "5: slgr %0,%0\n"
162 "6: sacf 768\n"
163 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
164 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
165 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
166 : : "cc", "memory");
167 disable_sacf_uaccess(old_fs);
168 return size;
169 }
170
171 unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
172 {
173 if (copy_with_mvcos())
174 return copy_from_user_mvcos(to, from, n);
175 return copy_from_user_mvcp(to, from, n);
176 }
177 EXPORT_SYMBOL(raw_copy_from_user);
178
179 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
180 unsigned long size)
181 {
182 register unsigned long reg0 asm("0") = 0x010000UL;
183 unsigned long tmp1, tmp2;
184
185 tmp1 = -4096UL;
186 asm volatile(
187 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
188 "6: jz 4f\n"
189 "1: algr %0,%3\n"
190 " slgr %1,%3\n"
191 " slgr %2,%3\n"
192 " j 0b\n"
193 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
194 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
195 " slgr %4,%1\n"
196 " clgr %0,%4\n" /* copy crosses next page boundary? */
197 " jnh 5f\n"
198 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
199 "7: slgr %0,%4\n"
200 " j 5f\n"
201 "4: slgr %0,%0\n"
202 "5:\n"
203 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
204 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
205 : "d" (reg0) : "cc", "memory");
206 return size;
207 }
208
209 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
210 unsigned long size)
211 {
212 unsigned long tmp1, tmp2;
213 mm_segment_t old_fs;
214
215 old_fs = enable_sacf_uaccess();
216 tmp1 = -256UL;
217 asm volatile(
218 " sacf 0\n"
219 "0: mvcs 0(%0,%1),0(%2),%3\n"
220 "7: jz 5f\n"
221 "1: algr %0,%3\n"
222 " la %1,256(%1)\n"
223 " la %2,256(%2)\n"
224 "2: mvcs 0(%0,%1),0(%2),%3\n"
225 "8: jnz 1b\n"
226 " j 5f\n"
227 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
228 " lghi %3,-4096\n"
229 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
230 " slgr %4,%1\n"
231 " clgr %0,%4\n" /* copy crosses next page boundary? */
232 " jnh 6f\n"
233 "4: mvcs 0(%4,%1),0(%2),%3\n"
234 "9: slgr %0,%4\n"
235 " j 6f\n"
236 "5: slgr %0,%0\n"
237 "6: sacf 768\n"
238 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
239 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
240 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
241 : : "cc", "memory");
242 disable_sacf_uaccess(old_fs);
243 return size;
244 }
245
246 unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
247 {
248 if (copy_with_mvcos())
249 return copy_to_user_mvcos(to, from, n);
250 return copy_to_user_mvcs(to, from, n);
251 }
252 EXPORT_SYMBOL(raw_copy_to_user);
253
254 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
255 unsigned long size)
256 {
257 register unsigned long reg0 asm("0") = 0x010001UL;
258 unsigned long tmp1, tmp2;
259
260 tmp1 = -4096UL;
261 /* FIXME: copy with reduced length. */
262 asm volatile(
263 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
264 " jz 2f\n"
265 "1: algr %0,%3\n"
266 " slgr %1,%3\n"
267 " slgr %2,%3\n"
268 " j 0b\n"
269 "2:slgr %0,%0\n"
270 "3: \n"
271 EX_TABLE(0b,3b)
272 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
273 : "d" (reg0) : "cc", "memory");
274 return size;
275 }
276
277 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
278 unsigned long size)
279 {
280 mm_segment_t old_fs;
281 unsigned long tmp1;
282
283 old_fs = enable_sacf_uaccess();
284 asm volatile(
285 " sacf 256\n"
286 " aghi %0,-1\n"
287 " jo 5f\n"
288 " bras %3,3f\n"
289 "0: aghi %0,257\n"
290 "1: mvc 0(1,%1),0(%2)\n"
291 " la %1,1(%1)\n"
292 " la %2,1(%2)\n"
293 " aghi %0,-1\n"
294 " jnz 1b\n"
295 " j 5f\n"
296 "2: mvc 0(256,%1),0(%2)\n"
297 " la %1,256(%1)\n"
298 " la %2,256(%2)\n"
299 "3: aghi %0,-256\n"
300 " jnm 2b\n"
301 "4: ex %0,1b-0b(%3)\n"
302 "5: slgr %0,%0\n"
303 "6: sacf 768\n"
304 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
305 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
306 : : "cc", "memory");
307 disable_sacf_uaccess(old_fs);
308 return size;
309 }
310
311 unsigned long raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
312 {
313 if (copy_with_mvcos())
314 return copy_in_user_mvcos(to, from, n);
315 return copy_in_user_mvc(to, from, n);
316 }
317 EXPORT_SYMBOL(raw_copy_in_user);
318
319 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
320 {
321 register unsigned long reg0 asm("0") = 0x010000UL;
322 unsigned long tmp1, tmp2;
323
324 tmp1 = -4096UL;
325 asm volatile(
326 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
327 " jz 4f\n"
328 "1: algr %0,%2\n"
329 " slgr %1,%2\n"
330 " j 0b\n"
331 "2: la %3,4095(%1)\n"/* %4 = to + 4095 */
332 " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
333 " slgr %3,%1\n"
334 " clgr %0,%3\n" /* copy crosses next page boundary? */
335 " jnh 5f\n"
336 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
337 " slgr %0,%3\n"
338 " j 5f\n"
339 "4: slgr %0,%0\n"
340 "5:\n"
341 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
342 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
343 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
344 return size;
345 }
346
347 static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
348 {
349 mm_segment_t old_fs;
350 unsigned long tmp1, tmp2;
351
352 old_fs = enable_sacf_uaccess();
353 asm volatile(
354 " sacf 256\n"
355 " aghi %0,-1\n"
356 " jo 5f\n"
357 " bras %3,3f\n"
358 " xc 0(1,%1),0(%1)\n"
359 "0: aghi %0,257\n"
360 " la %2,255(%1)\n" /* %2 = ptr + 255 */
361 " srl %2,12\n"
362 " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */
363 " slgr %2,%1\n"
364 " clgr %0,%2\n" /* clear crosses next page boundary? */
365 " jnh 5f\n"
366 " aghi %2,-1\n"
367 "1: ex %2,0(%3)\n"
368 " aghi %2,1\n"
369 " slgr %0,%2\n"
370 " j 5f\n"
371 "2: xc 0(256,%1),0(%1)\n"
372 " la %1,256(%1)\n"
373 "3: aghi %0,-256\n"
374 " jnm 2b\n"
375 "4: ex %0,0(%3)\n"
376 "5: slgr %0,%0\n"
377 "6: sacf 768\n"
378 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
379 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
380 : : "cc", "memory");
381 disable_sacf_uaccess(old_fs);
382 return size;
383 }
384
385 unsigned long __clear_user(void __user *to, unsigned long size)
386 {
387 if (copy_with_mvcos())
388 return clear_user_mvcos(to, size);
389 return clear_user_xc(to, size);
390 }
391 EXPORT_SYMBOL(__clear_user);
392
393 static inline unsigned long strnlen_user_srst(const char __user *src,
394 unsigned long size)
395 {
396 register unsigned long reg0 asm("0") = 0;
397 unsigned long tmp1, tmp2;
398
399 asm volatile(
400 " la %2,0(%1)\n"
401 " la %3,0(%0,%1)\n"
402 " slgr %0,%0\n"
403 " sacf 256\n"
404 "0: srst %3,%2\n"
405 " jo 0b\n"
406 " la %0,1(%3)\n" /* strnlen_user results includes \0 */
407 " slgr %0,%1\n"
408 "1: sacf 768\n"
409 EX_TABLE(0b,1b)
410 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
411 : "d" (reg0) : "cc", "memory");
412 return size;
413 }
414
415 unsigned long __strnlen_user(const char __user *src, unsigned long size)
416 {
417 mm_segment_t old_fs;
418 unsigned long len;
419
420 if (unlikely(!size))
421 return 0;
422 old_fs = enable_sacf_uaccess();
423 len = strnlen_user_srst(src, size);
424 disable_sacf_uaccess(old_fs);
425 return len;
426 }
427 EXPORT_SYMBOL(__strnlen_user);
428
429 long __strncpy_from_user(char *dst, const char __user *src, long size)
430 {
431 size_t done, len, offset, len_str;
432
433 if (unlikely(size <= 0))
434 return 0;
435 done = 0;
436 do {
437 offset = (size_t)src & (L1_CACHE_BYTES - 1);
438 len = min(size - done, L1_CACHE_BYTES - offset);
439 if (copy_from_user(dst, src, len))
440 return -EFAULT;
441 len_str = strnlen(dst, len);
442 done += len_str;
443 src += len_str;
444 dst += len_str;
445 } while ((len_str == len) && (done < size));
446 return done;
447 }
448 EXPORT_SYMBOL(__strncpy_from_user);
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