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