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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/uaccess.h>
12#include <linux/export.h>
13#include <linux/mm.h>
14#include <asm/asm-extable.h>
15
16#ifdef CONFIG_DEBUG_ENTRY
17void debug_user_asce(int exit)
18{
19 unsigned long cr1, cr7;
20
21 __ctl_store(cr1, 1, 1);
22 __ctl_store(cr7, 7, 7);
23 if (cr1 == S390_lowcore.kernel_asce && cr7 == S390_lowcore.user_asce)
24 return;
25 panic("incorrect ASCE on kernel %s\n"
26 "cr1: %016lx cr7: %016lx\n"
27 "kernel: %016llx user: %016llx\n",
28 exit ? "exit" : "entry", cr1, cr7,
29 S390_lowcore.kernel_asce, S390_lowcore.user_asce);
30
31}
32#endif /*CONFIG_DEBUG_ENTRY */
33
34static unsigned long raw_copy_from_user_key(void *to, const void __user *from,
35 unsigned long size, unsigned long key)
36{
37 unsigned long tmp1, tmp2;
38 union oac spec = {
39 .oac2.key = key,
40 .oac2.as = PSW_BITS_AS_SECONDARY,
41 .oac2.k = 1,
42 .oac2.a = 1,
43 };
44
45 tmp1 = -4096UL;
46 asm volatile(
47 " lr 0,%[spec]\n"
48 "0: mvcos 0(%2),0(%1),%0\n"
49 "6: jz 4f\n"
50 "1: algr %0,%3\n"
51 " slgr %1,%3\n"
52 " slgr %2,%3\n"
53 " j 0b\n"
54 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
55 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
56 " slgr %4,%1\n"
57 " clgr %0,%4\n" /* copy crosses next page boundary? */
58 " jnh 5f\n"
59 "3: mvcos 0(%2),0(%1),%4\n"
60 "7: slgr %0,%4\n"
61 " j 5f\n"
62 "4: slgr %0,%0\n"
63 "5:\n"
64 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
65 : "+a" (size), "+a" (from), "+a" (to), "+a" (tmp1), "=a" (tmp2)
66 : [spec] "d" (spec.val)
67 : "cc", "memory", "0");
68 return size;
69}
70
71unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n)
72{
73 return raw_copy_from_user_key(to, from, n, 0);
74}
75EXPORT_SYMBOL(raw_copy_from_user);
76
77unsigned long _copy_from_user_key(void *to, const void __user *from,
78 unsigned long n, unsigned long key)
79{
80 unsigned long res = n;
81
82 might_fault();
83 if (!should_fail_usercopy()) {
84 instrument_copy_from_user_before(to, from, n);
85 res = raw_copy_from_user_key(to, from, n, key);
86 instrument_copy_from_user_after(to, from, n, res);
87 }
88 if (unlikely(res))
89 memset(to + (n - res), 0, res);
90 return res;
91}
92EXPORT_SYMBOL(_copy_from_user_key);
93
94static unsigned long raw_copy_to_user_key(void __user *to, const void *from,
95 unsigned long size, unsigned long key)
96{
97 unsigned long tmp1, tmp2;
98 union oac spec = {
99 .oac1.key = key,
100 .oac1.as = PSW_BITS_AS_SECONDARY,
101 .oac1.k = 1,
102 .oac1.a = 1,
103 };
104
105 tmp1 = -4096UL;
106 asm volatile(
107 " lr 0,%[spec]\n"
108 "0: mvcos 0(%1),0(%2),%0\n"
109 "6: jz 4f\n"
110 "1: algr %0,%3\n"
111 " slgr %1,%3\n"
112 " slgr %2,%3\n"
113 " j 0b\n"
114 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
115 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
116 " slgr %4,%1\n"
117 " clgr %0,%4\n" /* copy crosses next page boundary? */
118 " jnh 5f\n"
119 "3: mvcos 0(%1),0(%2),%4\n"
120 "7: slgr %0,%4\n"
121 " j 5f\n"
122 "4: slgr %0,%0\n"
123 "5:\n"
124 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
125 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
126 : [spec] "d" (spec.val)
127 : "cc", "memory", "0");
128 return size;
129}
130
131unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n)
132{
133 return raw_copy_to_user_key(to, from, n, 0);
134}
135EXPORT_SYMBOL(raw_copy_to_user);
136
137unsigned long _copy_to_user_key(void __user *to, const void *from,
138 unsigned long n, unsigned long key)
139{
140 might_fault();
141 if (should_fail_usercopy())
142 return n;
143 instrument_copy_to_user(to, from, n);
144 return raw_copy_to_user_key(to, from, n, key);
145}
146EXPORT_SYMBOL(_copy_to_user_key);
147
148unsigned long __clear_user(void __user *to, unsigned long size)
149{
150 unsigned long tmp1, tmp2;
151 union oac spec = {
152 .oac1.as = PSW_BITS_AS_SECONDARY,
153 .oac1.a = 1,
154 };
155
156 tmp1 = -4096UL;
157 asm volatile(
158 " lr 0,%[spec]\n"
159 "0: mvcos 0(%1),0(%4),%0\n"
160 "6: jz 4f\n"
161 "1: algr %0,%2\n"
162 " slgr %1,%2\n"
163 " j 0b\n"
164 "2: la %3,4095(%1)\n"/* %4 = to + 4095 */
165 " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
166 " slgr %3,%1\n"
167 " clgr %0,%3\n" /* copy crosses next page boundary? */
168 " jnh 5f\n"
169 "3: mvcos 0(%1),0(%4),%3\n"
170 "7: slgr %0,%3\n"
171 " j 5f\n"
172 "4: slgr %0,%0\n"
173 "5:\n"
174 EX_TABLE(0b,2b) EX_TABLE(6b,2b) EX_TABLE(3b,5b) EX_TABLE(7b,5b)
175 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
176 : "a" (empty_zero_page), [spec] "d" (spec.val)
177 : "cc", "memory", "0");
178 return size;
179}
180EXPORT_SYMBOL(__clear_user);
1/*
2 * Standard user space access functions based on mvcp/mvcs and doing
3 * interesting things in the secondary space mode.
4 *
5 * Copyright IBM Corp. 2006,2014
6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
7 * Gerald Schaefer (gerald.schaefer@de.ibm.com)
8 */
9
10#include <linux/jump_label.h>
11#include <linux/uaccess.h>
12#include <linux/export.h>
13#include <linux/errno.h>
14#include <linux/mm.h>
15#include <asm/mmu_context.h>
16#include <asm/facility.h>
17
18#ifndef CONFIG_64BIT
19#define AHI "ahi"
20#define ALR "alr"
21#define CLR "clr"
22#define LHI "lhi"
23#define SLR "slr"
24#else
25#define AHI "aghi"
26#define ALR "algr"
27#define CLR "clgr"
28#define LHI "lghi"
29#define SLR "slgr"
30#endif
31
32static struct static_key have_mvcos = STATIC_KEY_INIT_FALSE;
33
34static inline unsigned long copy_from_user_mvcos(void *x, const void __user *ptr,
35 unsigned long size)
36{
37 register unsigned long reg0 asm("0") = 0x81UL;
38 unsigned long tmp1, tmp2;
39
40 tmp1 = -4096UL;
41 asm volatile(
42 "0: .insn ss,0xc80000000000,0(%0,%2),0(%1),0\n"
43 "9: jz 7f\n"
44 "1:"ALR" %0,%3\n"
45 " "SLR" %1,%3\n"
46 " "SLR" %2,%3\n"
47 " j 0b\n"
48 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
49 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
50 " "SLR" %4,%1\n"
51 " "CLR" %0,%4\n" /* copy crosses next page boundary? */
52 " jnh 4f\n"
53 "3: .insn ss,0xc80000000000,0(%4,%2),0(%1),0\n"
54 "10:"SLR" %0,%4\n"
55 " "ALR" %2,%4\n"
56 "4:"LHI" %4,-1\n"
57 " "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
58 " bras %3,6f\n" /* memset loop */
59 " xc 0(1,%2),0(%2)\n"
60 "5: xc 0(256,%2),0(%2)\n"
61 " la %2,256(%2)\n"
62 "6:"AHI" %4,-256\n"
63 " jnm 5b\n"
64 " ex %4,0(%3)\n"
65 " j 8f\n"
66 "7:"SLR" %0,%0\n"
67 "8:\n"
68 EX_TABLE(0b,2b) EX_TABLE(3b,4b) EX_TABLE(9b,2b) EX_TABLE(10b,4b)
69 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
70 : "d" (reg0) : "cc", "memory");
71 return size;
72}
73
74static inline unsigned long copy_from_user_mvcp(void *x, const void __user *ptr,
75 unsigned long size)
76{
77 unsigned long tmp1, tmp2;
78
79 update_primary_asce(current);
80 tmp1 = -256UL;
81 asm volatile(
82 " sacf 0\n"
83 "0: mvcp 0(%0,%2),0(%1),%3\n"
84 "10:jz 8f\n"
85 "1:"ALR" %0,%3\n"
86 " la %1,256(%1)\n"
87 " la %2,256(%2)\n"
88 "2: mvcp 0(%0,%2),0(%1),%3\n"
89 "11:jnz 1b\n"
90 " j 8f\n"
91 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
92 " "LHI" %3,-4096\n"
93 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
94 " "SLR" %4,%1\n"
95 " "CLR" %0,%4\n" /* copy crosses next page boundary? */
96 " jnh 5f\n"
97 "4: mvcp 0(%4,%2),0(%1),%3\n"
98 "12:"SLR" %0,%4\n"
99 " "ALR" %2,%4\n"
100 "5:"LHI" %4,-1\n"
101 " "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
102 " bras %3,7f\n" /* memset loop */
103 " xc 0(1,%2),0(%2)\n"
104 "6: xc 0(256,%2),0(%2)\n"
105 " la %2,256(%2)\n"
106 "7:"AHI" %4,-256\n"
107 " jnm 6b\n"
108 " ex %4,0(%3)\n"
109 " j 9f\n"
110 "8:"SLR" %0,%0\n"
111 "9: sacf 768\n"
112 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
113 EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
114 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
115 : : "cc", "memory");
116 return size;
117}
118
119unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
120{
121 if (static_key_false(&have_mvcos))
122 return copy_from_user_mvcos(to, from, n);
123 return copy_from_user_mvcp(to, from, n);
124}
125EXPORT_SYMBOL(__copy_from_user);
126
127static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
128 unsigned long size)
129{
130 register unsigned long reg0 asm("0") = 0x810000UL;
131 unsigned long tmp1, tmp2;
132
133 tmp1 = -4096UL;
134 asm volatile(
135 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
136 "6: jz 4f\n"
137 "1:"ALR" %0,%3\n"
138 " "SLR" %1,%3\n"
139 " "SLR" %2,%3\n"
140 " j 0b\n"
141 "2: la %4,4095(%1)\n"/* %4 = ptr + 4095 */
142 " nr %4,%3\n" /* %4 = (ptr + 4095) & -4096 */
143 " "SLR" %4,%1\n"
144 " "CLR" %0,%4\n" /* copy crosses next page boundary? */
145 " jnh 5f\n"
146 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
147 "7:"SLR" %0,%4\n"
148 " j 5f\n"
149 "4:"SLR" %0,%0\n"
150 "5:\n"
151 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
152 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
153 : "d" (reg0) : "cc", "memory");
154 return size;
155}
156
157static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
158 unsigned long size)
159{
160 unsigned long tmp1, tmp2;
161
162 update_primary_asce(current);
163 tmp1 = -256UL;
164 asm volatile(
165 " sacf 0\n"
166 "0: mvcs 0(%0,%1),0(%2),%3\n"
167 "7: jz 5f\n"
168 "1:"ALR" %0,%3\n"
169 " la %1,256(%1)\n"
170 " la %2,256(%2)\n"
171 "2: mvcs 0(%0,%1),0(%2),%3\n"
172 "8: jnz 1b\n"
173 " j 5f\n"
174 "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
175 " "LHI" %3,-4096\n"
176 " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
177 " "SLR" %4,%1\n"
178 " "CLR" %0,%4\n" /* copy crosses next page boundary? */
179 " jnh 6f\n"
180 "4: mvcs 0(%4,%1),0(%2),%3\n"
181 "9:"SLR" %0,%4\n"
182 " j 6f\n"
183 "5:"SLR" %0,%0\n"
184 "6: sacf 768\n"
185 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
186 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
187 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
188 : : "cc", "memory");
189 return size;
190}
191
192unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
193{
194 if (static_key_false(&have_mvcos))
195 return copy_to_user_mvcos(to, from, n);
196 return copy_to_user_mvcs(to, from, n);
197}
198EXPORT_SYMBOL(__copy_to_user);
199
200static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
201 unsigned long size)
202{
203 register unsigned long reg0 asm("0") = 0x810081UL;
204 unsigned long tmp1, tmp2;
205
206 tmp1 = -4096UL;
207 /* FIXME: copy with reduced length. */
208 asm volatile(
209 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
210 " jz 2f\n"
211 "1:"ALR" %0,%3\n"
212 " "SLR" %1,%3\n"
213 " "SLR" %2,%3\n"
214 " j 0b\n"
215 "2:"SLR" %0,%0\n"
216 "3: \n"
217 EX_TABLE(0b,3b)
218 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
219 : "d" (reg0) : "cc", "memory");
220 return size;
221}
222
223static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
224 unsigned long size)
225{
226 unsigned long tmp1;
227
228 update_primary_asce(current);
229 asm volatile(
230 " sacf 256\n"
231 " "AHI" %0,-1\n"
232 " jo 5f\n"
233 " bras %3,3f\n"
234 "0:"AHI" %0,257\n"
235 "1: mvc 0(1,%1),0(%2)\n"
236 " la %1,1(%1)\n"
237 " la %2,1(%2)\n"
238 " "AHI" %0,-1\n"
239 " jnz 1b\n"
240 " j 5f\n"
241 "2: mvc 0(256,%1),0(%2)\n"
242 " la %1,256(%1)\n"
243 " la %2,256(%2)\n"
244 "3:"AHI" %0,-256\n"
245 " jnm 2b\n"
246 "4: ex %0,1b-0b(%3)\n"
247 "5: "SLR" %0,%0\n"
248 "6: sacf 768\n"
249 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
250 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
251 : : "cc", "memory");
252 return size;
253}
254
255unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n)
256{
257 if (static_key_false(&have_mvcos))
258 return copy_in_user_mvcos(to, from, n);
259 return copy_in_user_mvc(to, from, n);
260}
261EXPORT_SYMBOL(__copy_in_user);
262
263static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
264{
265 register unsigned long reg0 asm("0") = 0x810000UL;
266 unsigned long tmp1, tmp2;
267
268 tmp1 = -4096UL;
269 asm volatile(
270 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
271 " jz 4f\n"
272 "1:"ALR" %0,%2\n"
273 " "SLR" %1,%2\n"
274 " j 0b\n"
275 "2: la %3,4095(%1)\n"/* %4 = to + 4095 */
276 " nr %3,%2\n" /* %4 = (to + 4095) & -4096 */
277 " "SLR" %3,%1\n"
278 " "CLR" %0,%3\n" /* copy crosses next page boundary? */
279 " jnh 5f\n"
280 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
281 " "SLR" %0,%3\n"
282 " j 5f\n"
283 "4:"SLR" %0,%0\n"
284 "5:\n"
285 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
286 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
287 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
288 return size;
289}
290
291static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
292{
293 unsigned long tmp1, tmp2;
294
295 update_primary_asce(current);
296 asm volatile(
297 " sacf 256\n"
298 " "AHI" %0,-1\n"
299 " jo 5f\n"
300 " bras %3,3f\n"
301 " xc 0(1,%1),0(%1)\n"
302 "0:"AHI" %0,257\n"
303 " la %2,255(%1)\n" /* %2 = ptr + 255 */
304 " srl %2,12\n"
305 " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */
306 " "SLR" %2,%1\n"
307 " "CLR" %0,%2\n" /* clear crosses next page boundary? */
308 " jnh 5f\n"
309 " "AHI" %2,-1\n"
310 "1: ex %2,0(%3)\n"
311 " "AHI" %2,1\n"
312 " "SLR" %0,%2\n"
313 " j 5f\n"
314 "2: xc 0(256,%1),0(%1)\n"
315 " la %1,256(%1)\n"
316 "3:"AHI" %0,-256\n"
317 " jnm 2b\n"
318 "4: ex %0,0(%3)\n"
319 "5: "SLR" %0,%0\n"
320 "6: sacf 768\n"
321 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
322 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
323 : : "cc", "memory");
324 return size;
325}
326
327unsigned long __clear_user(void __user *to, unsigned long size)
328{
329 if (static_key_false(&have_mvcos))
330 return clear_user_mvcos(to, size);
331 return clear_user_xc(to, size);
332}
333EXPORT_SYMBOL(__clear_user);
334
335static inline unsigned long strnlen_user_srst(const char __user *src,
336 unsigned long size)
337{
338 register unsigned long reg0 asm("0") = 0;
339 unsigned long tmp1, tmp2;
340
341 asm volatile(
342 " la %2,0(%1)\n"
343 " la %3,0(%0,%1)\n"
344 " "SLR" %0,%0\n"
345 " sacf 256\n"
346 "0: srst %3,%2\n"
347 " jo 0b\n"
348 " la %0,1(%3)\n" /* strnlen_user results includes \0 */
349 " "SLR" %0,%1\n"
350 "1: sacf 768\n"
351 EX_TABLE(0b,1b)
352 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
353 : "d" (reg0) : "cc", "memory");
354 return size;
355}
356
357unsigned long __strnlen_user(const char __user *src, unsigned long size)
358{
359 if (unlikely(!size))
360 return 0;
361 update_primary_asce(current);
362 return strnlen_user_srst(src, size);
363}
364EXPORT_SYMBOL(__strnlen_user);
365
366long __strncpy_from_user(char *dst, const char __user *src, long size)
367{
368 size_t done, len, offset, len_str;
369
370 if (unlikely(size <= 0))
371 return 0;
372 done = 0;
373 do {
374 offset = (size_t)src & ~PAGE_MASK;
375 len = min(size - done, PAGE_SIZE - offset);
376 if (copy_from_user(dst, src, len))
377 return -EFAULT;
378 len_str = strnlen(dst, len);
379 done += len_str;
380 src += len_str;
381 dst += len_str;
382 } while ((len_str == len) && (done < size));
383 return done;
384}
385EXPORT_SYMBOL(__strncpy_from_user);
386
387/*
388 * The "old" uaccess variant without mvcos can be enforced with the
389 * uaccess_primary kernel parameter. This is mainly for debugging purposes.
390 */
391static int uaccess_primary __initdata;
392
393static int __init parse_uaccess_pt(char *__unused)
394{
395 uaccess_primary = 1;
396 return 0;
397}
398early_param("uaccess_primary", parse_uaccess_pt);
399
400static int __init uaccess_init(void)
401{
402 if (IS_ENABLED(CONFIG_64BIT) && !uaccess_primary && test_facility(27))
403 static_key_slow_inc(&have_mvcos);
404 return 0;
405}
406early_initcall(uaccess_init);