GNU Linux-libre 4.9.288-gnu1
[releases.git] / arch / s390 / lib / uaccess.c
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 static DEFINE_STATIC_KEY_FALSE(have_mvcos);
19
20 static 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
60 static 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
105 unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n)
106 {
107         check_object_size(to, n, false);
108         if (static_branch_likely(&have_mvcos))
109                 return copy_from_user_mvcos(to, from, n);
110         return copy_from_user_mvcp(to, from, n);
111 }
112 EXPORT_SYMBOL(__copy_from_user);
113
114 static inline unsigned long copy_to_user_mvcos(void __user *ptr, const void *x,
115                                                unsigned long size)
116 {
117         register unsigned long reg0 asm("0") = 0x810000UL;
118         unsigned long tmp1, tmp2;
119
120         tmp1 = -4096UL;
121         asm volatile(
122                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
123                 "6: jz    4f\n"
124                 "1: algr  %0,%3\n"
125                 "   slgr  %1,%3\n"
126                 "   slgr  %2,%3\n"
127                 "   j     0b\n"
128                 "2: la    %4,4095(%1)\n"/* %4 = ptr + 4095 */
129                 "   nr    %4,%3\n"      /* %4 = (ptr + 4095) & -4096 */
130                 "   slgr  %4,%1\n"
131                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
132                 "   jnh   5f\n"
133                 "3: .insn ss,0xc80000000000,0(%4,%1),0(%2),0\n"
134                 "7: slgr  %0,%4\n"
135                 "   j     5f\n"
136                 "4: slgr  %0,%0\n"
137                 "5:\n"
138                 EX_TABLE(0b,2b) EX_TABLE(3b,5b) EX_TABLE(6b,2b) EX_TABLE(7b,5b)
139                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
140                 : "d" (reg0) : "cc", "memory");
141         return size;
142 }
143
144 static inline unsigned long copy_to_user_mvcs(void __user *ptr, const void *x,
145                                               unsigned long size)
146 {
147         unsigned long tmp1, tmp2;
148
149         load_kernel_asce();
150         tmp1 = -256UL;
151         asm volatile(
152                 "   sacf  0\n"
153                 "0: mvcs  0(%0,%1),0(%2),%3\n"
154                 "7: jz    5f\n"
155                 "1: algr  %0,%3\n"
156                 "   la    %1,256(%1)\n"
157                 "   la    %2,256(%2)\n"
158                 "2: mvcs  0(%0,%1),0(%2),%3\n"
159                 "8: jnz   1b\n"
160                 "   j     5f\n"
161                 "3: la    %4,255(%1)\n" /* %4 = ptr + 255 */
162                 "   lghi  %3,-4096\n"
163                 "   nr    %4,%3\n"      /* %4 = (ptr + 255) & -4096 */
164                 "   slgr  %4,%1\n"
165                 "   clgr  %0,%4\n"      /* copy crosses next page boundary? */
166                 "   jnh   6f\n"
167                 "4: mvcs  0(%4,%1),0(%2),%3\n"
168                 "9: slgr  %0,%4\n"
169                 "   j     6f\n"
170                 "5: slgr  %0,%0\n"
171                 "6: sacf  768\n"
172                 EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
173                 EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
174                 : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
175                 : : "cc", "memory");
176         return size;
177 }
178
179 unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
180 {
181         check_object_size(from, n, true);
182         if (static_branch_likely(&have_mvcos))
183                 return copy_to_user_mvcos(to, from, n);
184         return copy_to_user_mvcs(to, from, n);
185 }
186 EXPORT_SYMBOL(__copy_to_user);
187
188 static inline unsigned long copy_in_user_mvcos(void __user *to, const void __user *from,
189                                                unsigned long size)
190 {
191         register unsigned long reg0 asm("0") = 0x810081UL;
192         unsigned long tmp1, tmp2;
193
194         tmp1 = -4096UL;
195         /* FIXME: copy with reduced length. */
196         asm volatile(
197                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%2),0\n"
198                 "   jz    2f\n"
199                 "1: algr  %0,%3\n"
200                 "   slgr  %1,%3\n"
201                 "   slgr  %2,%3\n"
202                 "   j     0b\n"
203                 "2:slgr  %0,%0\n"
204                 "3: \n"
205                 EX_TABLE(0b,3b)
206                 : "+a" (size), "+a" (to), "+a" (from), "+a" (tmp1), "=a" (tmp2)
207                 : "d" (reg0) : "cc", "memory");
208         return size;
209 }
210
211 static inline unsigned long copy_in_user_mvc(void __user *to, const void __user *from,
212                                              unsigned long size)
213 {
214         unsigned long tmp1;
215
216         load_kernel_asce();
217         asm volatile(
218                 "   sacf  256\n"
219                 "   aghi  %0,-1\n"
220                 "   jo    5f\n"
221                 "   bras  %3,3f\n"
222                 "0: aghi  %0,257\n"
223                 "1: mvc   0(1,%1),0(%2)\n"
224                 "   la    %1,1(%1)\n"
225                 "   la    %2,1(%2)\n"
226                 "   aghi  %0,-1\n"
227                 "   jnz   1b\n"
228                 "   j     5f\n"
229                 "2: mvc   0(256,%1),0(%2)\n"
230                 "   la    %1,256(%1)\n"
231                 "   la    %2,256(%2)\n"
232                 "3: aghi  %0,-256\n"
233                 "   jnm   2b\n"
234                 "4: ex    %0,1b-0b(%3)\n"
235                 "5: slgr  %0,%0\n"
236                 "6: sacf  768\n"
237                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
238                 : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
239                 : : "cc", "memory");
240         return size;
241 }
242
243 unsigned long __copy_in_user(void __user *to, const void __user *from, unsigned long n)
244 {
245         if (static_branch_likely(&have_mvcos))
246                 return copy_in_user_mvcos(to, from, n);
247         return copy_in_user_mvc(to, from, n);
248 }
249 EXPORT_SYMBOL(__copy_in_user);
250
251 static inline unsigned long clear_user_mvcos(void __user *to, unsigned long size)
252 {
253         register unsigned long reg0 asm("0") = 0x810000UL;
254         unsigned long tmp1, tmp2;
255
256         tmp1 = -4096UL;
257         asm volatile(
258                 "0: .insn ss,0xc80000000000,0(%0,%1),0(%4),0\n"
259                 "   jz    4f\n"
260                 "1: algr  %0,%2\n"
261                 "   slgr  %1,%2\n"
262                 "   j     0b\n"
263                 "2: la    %3,4095(%1)\n"/* %4 = to + 4095 */
264                 "   nr    %3,%2\n"      /* %4 = (to + 4095) & -4096 */
265                 "   slgr  %3,%1\n"
266                 "   clgr  %0,%3\n"      /* copy crosses next page boundary? */
267                 "   jnh   5f\n"
268                 "3: .insn ss,0xc80000000000,0(%3,%1),0(%4),0\n"
269                 "   slgr  %0,%3\n"
270                 "   j     5f\n"
271                 "4: slgr  %0,%0\n"
272                 "5:\n"
273                 EX_TABLE(0b,2b) EX_TABLE(3b,5b)
274                 : "+a" (size), "+a" (to), "+a" (tmp1), "=a" (tmp2)
275                 : "a" (empty_zero_page), "d" (reg0) : "cc", "memory");
276         return size;
277 }
278
279 static inline unsigned long clear_user_xc(void __user *to, unsigned long size)
280 {
281         unsigned long tmp1, tmp2;
282
283         load_kernel_asce();
284         asm volatile(
285                 "   sacf  256\n"
286                 "   aghi  %0,-1\n"
287                 "   jo    5f\n"
288                 "   bras  %3,3f\n"
289                 "   xc    0(1,%1),0(%1)\n"
290                 "0: aghi  %0,257\n"
291                 "   la    %2,255(%1)\n" /* %2 = ptr + 255 */
292                 "   srl   %2,12\n"
293                 "   sll   %2,12\n"      /* %2 = (ptr + 255) & -4096 */
294                 "   slgr  %2,%1\n"
295                 "   clgr  %0,%2\n"      /* clear crosses next page boundary? */
296                 "   jnh   5f\n"
297                 "   aghi  %2,-1\n"
298                 "1: ex    %2,0(%3)\n"
299                 "   aghi  %2,1\n"
300                 "   slgr  %0,%2\n"
301                 "   j     5f\n"
302                 "2: xc    0(256,%1),0(%1)\n"
303                 "   la    %1,256(%1)\n"
304                 "3: aghi  %0,-256\n"
305                 "   jnm   2b\n"
306                 "4: ex    %0,0(%3)\n"
307                 "5: slgr  %0,%0\n"
308                 "6: sacf  768\n"
309                 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
310                 : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
311                 : : "cc", "memory");
312         return size;
313 }
314
315 unsigned long __clear_user(void __user *to, unsigned long size)
316 {
317         if (static_branch_likely(&have_mvcos))
318                         return clear_user_mvcos(to, size);
319         return clear_user_xc(to, size);
320 }
321 EXPORT_SYMBOL(__clear_user);
322
323 static inline unsigned long strnlen_user_srst(const char __user *src,
324                                               unsigned long size)
325 {
326         register unsigned long reg0 asm("0") = 0;
327         unsigned long tmp1, tmp2;
328
329         asm volatile(
330                 "   la    %2,0(%1)\n"
331                 "   la    %3,0(%0,%1)\n"
332                 "   slgr  %0,%0\n"
333                 "   sacf  256\n"
334                 "0: srst  %3,%2\n"
335                 "   jo    0b\n"
336                 "   la    %0,1(%3)\n"   /* strnlen_user results includes \0 */
337                 "   slgr  %0,%1\n"
338                 "1: sacf  768\n"
339                 EX_TABLE(0b,1b)
340                 : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
341                 : "d" (reg0) : "cc", "memory");
342         return size;
343 }
344
345 unsigned long __strnlen_user(const char __user *src, unsigned long size)
346 {
347         if (unlikely(!size))
348                 return 0;
349         load_kernel_asce();
350         return strnlen_user_srst(src, size);
351 }
352 EXPORT_SYMBOL(__strnlen_user);
353
354 long __strncpy_from_user(char *dst, const char __user *src, long size)
355 {
356         size_t done, len, offset, len_str;
357
358         if (unlikely(size <= 0))
359                 return 0;
360         done = 0;
361         do {
362                 offset = (size_t)src & ~PAGE_MASK;
363                 len = min(size - done, PAGE_SIZE - offset);
364                 if (copy_from_user(dst, src, len))
365                         return -EFAULT;
366                 len_str = strnlen(dst, len);
367                 done += len_str;
368                 src += len_str;
369                 dst += len_str;
370         } while ((len_str == len) && (done < size));
371         return done;
372 }
373 EXPORT_SYMBOL(__strncpy_from_user);
374
375 static int __init uaccess_init(void)
376 {
377         if (test_facility(27))
378                 static_branch_enable(&have_mvcos);
379         return 0;
380 }
381 early_initcall(uaccess_init);