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uaccess_std.c
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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
6  * Author(s): Martin Schwidefsky ([email protected]),
7  * Gerald Schaefer ([email protected])
8  */
9 
10 #include <linux/errno.h>
11 #include <linux/mm.h>
12 #include <linux/uaccess.h>
13 #include <asm/futex.h>
14 #include "uaccess.h"
15 
16 #ifndef CONFIG_64BIT
17 #define AHI "ahi"
18 #define ALR "alr"
19 #define CLR "clr"
20 #define LHI "lhi"
21 #define SLR "slr"
22 #else
23 #define AHI "aghi"
24 #define ALR "algr"
25 #define CLR "clgr"
26 #define LHI "lghi"
27 #define SLR "slgr"
28 #endif
29 
30 size_t copy_from_user_std(size_t size, const void __user *ptr, void *x)
31 {
32  unsigned long tmp1, tmp2;
33 
34  tmp1 = -256UL;
35  asm volatile(
36  "0: mvcp 0(%0,%2),0(%1),%3\n"
37  "10:jz 8f\n"
38  "1:"ALR" %0,%3\n"
39  " la %1,256(%1)\n"
40  " la %2,256(%2)\n"
41  "2: mvcp 0(%0,%2),0(%1),%3\n"
42  "11:jnz 1b\n"
43  " j 8f\n"
44  "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
45  " "LHI" %3,-4096\n"
46  " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
47  " "SLR" %4,%1\n"
48  " "CLR" %0,%4\n" /* copy crosses next page boundary? */
49  " jnh 5f\n"
50  "4: mvcp 0(%4,%2),0(%1),%3\n"
51  "12:"SLR" %0,%4\n"
52  " "ALR" %2,%4\n"
53  "5:"LHI" %4,-1\n"
54  " "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
55  " bras %3,7f\n" /* memset loop */
56  " xc 0(1,%2),0(%2)\n"
57  "6: xc 0(256,%2),0(%2)\n"
58  " la %2,256(%2)\n"
59  "7:"AHI" %4,-256\n"
60  " jnm 6b\n"
61  " ex %4,0(%3)\n"
62  " j 9f\n"
63  "8:"SLR" %0,%0\n"
64  "9: \n"
65  EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,5b)
66  EX_TABLE(10b,3b) EX_TABLE(11b,3b) EX_TABLE(12b,5b)
67  : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
68  : : "cc", "memory");
69  return size;
70 }
71 
72 static size_t copy_from_user_std_check(size_t size, const void __user *ptr,
73  void *x)
74 {
75  if (size <= 1024)
76  return copy_from_user_std(size, ptr, x);
77  return copy_from_user_pt(size, ptr, x);
78 }
79 
80 size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
81 {
82  unsigned long tmp1, tmp2;
83 
84  tmp1 = -256UL;
85  asm volatile(
86  "0: mvcs 0(%0,%1),0(%2),%3\n"
87  "7: jz 5f\n"
88  "1:"ALR" %0,%3\n"
89  " la %1,256(%1)\n"
90  " la %2,256(%2)\n"
91  "2: mvcs 0(%0,%1),0(%2),%3\n"
92  "8: jnz 1b\n"
93  " j 5f\n"
94  "3: la %4,255(%1)\n" /* %4 = ptr + 255 */
95  " "LHI" %3,-4096\n"
96  " nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
97  " "SLR" %4,%1\n"
98  " "CLR" %0,%4\n" /* copy crosses next page boundary? */
99  " jnh 6f\n"
100  "4: mvcs 0(%4,%1),0(%2),%3\n"
101  "9:"SLR" %0,%4\n"
102  " j 6f\n"
103  "5:"SLR" %0,%0\n"
104  "6: \n"
105  EX_TABLE(0b,3b) EX_TABLE(2b,3b) EX_TABLE(4b,6b)
106  EX_TABLE(7b,3b) EX_TABLE(8b,3b) EX_TABLE(9b,6b)
107  : "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
108  : : "cc", "memory");
109  return size;
110 }
111 
112 static size_t copy_to_user_std_check(size_t size, void __user *ptr,
113  const void *x)
114 {
115  if (size <= 1024)
116  return copy_to_user_std(size, ptr, x);
117  return copy_to_user_pt(size, ptr, x);
118 }
119 
120 static size_t copy_in_user_std(size_t size, void __user *to,
121  const void __user *from)
122 {
123  unsigned long tmp1;
124 
125  asm volatile(
126  " sacf 256\n"
127  " "AHI" %0,-1\n"
128  " jo 5f\n"
129  " bras %3,3f\n"
130  "0:"AHI" %0,257\n"
131  "1: mvc 0(1,%1),0(%2)\n"
132  " la %1,1(%1)\n"
133  " la %2,1(%2)\n"
134  " "AHI" %0,-1\n"
135  " jnz 1b\n"
136  " j 5f\n"
137  "2: mvc 0(256,%1),0(%2)\n"
138  " la %1,256(%1)\n"
139  " la %2,256(%2)\n"
140  "3:"AHI" %0,-256\n"
141  " jnm 2b\n"
142  "4: ex %0,1b-0b(%3)\n"
143  "5: "SLR" %0,%0\n"
144  "6: sacf 0\n"
145  EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
146  : "+a" (size), "+a" (to), "+a" (from), "=a" (tmp1)
147  : : "cc", "memory");
148  return size;
149 }
150 
151 static size_t clear_user_std(size_t size, void __user *to)
152 {
153  unsigned long tmp1, tmp2;
154 
155  asm volatile(
156  " sacf 256\n"
157  " "AHI" %0,-1\n"
158  " jo 5f\n"
159  " bras %3,3f\n"
160  " xc 0(1,%1),0(%1)\n"
161  "0:"AHI" %0,257\n"
162  " la %2,255(%1)\n" /* %2 = ptr + 255 */
163  " srl %2,12\n"
164  " sll %2,12\n" /* %2 = (ptr + 255) & -4096 */
165  " "SLR" %2,%1\n"
166  " "CLR" %0,%2\n" /* clear crosses next page boundary? */
167  " jnh 5f\n"
168  " "AHI" %2,-1\n"
169  "1: ex %2,0(%3)\n"
170  " "AHI" %2,1\n"
171  " "SLR" %0,%2\n"
172  " j 5f\n"
173  "2: xc 0(256,%1),0(%1)\n"
174  " la %1,256(%1)\n"
175  "3:"AHI" %0,-256\n"
176  " jnm 2b\n"
177  "4: ex %0,0(%3)\n"
178  "5: "SLR" %0,%0\n"
179  "6: sacf 0\n"
180  EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
181  : "+a" (size), "+a" (to), "=a" (tmp1), "=a" (tmp2)
182  : : "cc", "memory");
183  return size;
184 }
185 
186 size_t strnlen_user_std(size_t size, const char __user *src)
187 {
188  register unsigned long reg0 asm("0") = 0UL;
189  unsigned long tmp1, tmp2;
190 
191  asm volatile(
192  " la %2,0(%1)\n"
193  " la %3,0(%0,%1)\n"
194  " "SLR" %0,%0\n"
195  " sacf 256\n"
196  "0: srst %3,%2\n"
197  " jo 0b\n"
198  " la %0,1(%3)\n" /* strnlen_user results includes \0 */
199  " "SLR" %0,%1\n"
200  "1: sacf 0\n"
201  EX_TABLE(0b,1b)
202  : "+a" (size), "+a" (src), "=a" (tmp1), "=a" (tmp2)
203  : "d" (reg0) : "cc", "memory");
204  return size;
205 }
206 
207 size_t strncpy_from_user_std(size_t size, const char __user *src, char *dst)
208 {
209  register unsigned long reg0 asm("0") = 0UL;
210  unsigned long tmp1, tmp2;
211 
212  asm volatile(
213  " la %3,0(%1)\n"
214  " la %4,0(%0,%1)\n"
215  " sacf 256\n"
216  "0: srst %4,%3\n"
217  " jo 0b\n"
218  " sacf 0\n"
219  " la %0,0(%4)\n"
220  " jh 1f\n" /* found \0 in string ? */
221  " "AHI" %4,1\n" /* include \0 in copy */
222  "1:"SLR" %0,%1\n" /* %0 = return length (without \0) */
223  " "SLR" %4,%1\n" /* %4 = copy length (including \0) */
224  "2: mvcp 0(%4,%2),0(%1),%5\n"
225  " jz 9f\n"
226  "3:"AHI" %4,-256\n"
227  " la %1,256(%1)\n"
228  " la %2,256(%2)\n"
229  "4: mvcp 0(%4,%2),0(%1),%5\n"
230  " jnz 3b\n"
231  " j 9f\n"
232  "7: sacf 0\n"
233  "8:"LHI" %0,%6\n"
234  "9:\n"
235  EX_TABLE(0b,7b) EX_TABLE(2b,8b) EX_TABLE(4b,8b)
236  : "+a" (size), "+a" (src), "+d" (dst), "=a" (tmp1), "=a" (tmp2)
237  : "d" (reg0), "K" (-EFAULT) : "cc", "memory");
238  return size;
239 }
240 
241 #define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg) \
242  asm volatile( \
243  " sacf 256\n" \
244  "0: l %1,0(%6)\n" \
245  "1:"insn \
246  "2: cs %1,%2,0(%6)\n" \
247  "3: jl 1b\n" \
248  " lhi %0,0\n" \
249  "4: sacf 0\n" \
250  EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b) \
251  : "=d" (ret), "=&d" (oldval), "=&d" (newval), \
252  "=m" (*uaddr) \
253  : "0" (-EFAULT), "d" (oparg), "a" (uaddr), \
254  "m" (*uaddr) : "cc");
255 
256 int futex_atomic_op_std(int op, u32 __user *uaddr, int oparg, int *old)
257 {
258  int oldval = 0, newval, ret;
259 
260  switch (op) {
261  case FUTEX_OP_SET:
262  __futex_atomic_op("lr %2,%5\n",
263  ret, oldval, newval, uaddr, oparg);
264  break;
265  case FUTEX_OP_ADD:
266  __futex_atomic_op("lr %2,%1\nar %2,%5\n",
267  ret, oldval, newval, uaddr, oparg);
268  break;
269  case FUTEX_OP_OR:
270  __futex_atomic_op("lr %2,%1\nor %2,%5\n",
271  ret, oldval, newval, uaddr, oparg);
272  break;
273  case FUTEX_OP_ANDN:
274  __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
275  ret, oldval, newval, uaddr, oparg);
276  break;
277  case FUTEX_OP_XOR:
278  __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
279  ret, oldval, newval, uaddr, oparg);
280  break;
281  default:
282  ret = -ENOSYS;
283  }
284  *old = oldval;
285  return ret;
286 }
287 
288 int futex_atomic_cmpxchg_std(u32 *uval, u32 __user *uaddr,
289  u32 oldval, u32 newval)
290 {
291  int ret;
292 
293  asm volatile(
294  " sacf 256\n"
295  "0: cs %1,%4,0(%5)\n"
296  "1: la %0,0\n"
297  "2: sacf 0\n"
298  EX_TABLE(0b,2b) EX_TABLE(1b,2b)
299  : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
300  : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
301  : "cc", "memory" );
302  *uval = oldval;
303  return ret;
304 }
305 
306 struct uaccess_ops uaccess_std = {
307  .copy_from_user = copy_from_user_std_check,
308  .copy_from_user_small = copy_from_user_std,
309  .copy_to_user = copy_to_user_std_check,
310  .copy_to_user_small = copy_to_user_std,
311  .copy_in_user = copy_in_user_std,
312  .clear_user = clear_user_std,
313  .strnlen_user = strnlen_user_std,
314  .strncpy_from_user = strncpy_from_user_std,
315  .futex_atomic_op = futex_atomic_op_std,
316  .futex_atomic_cmpxchg = futex_atomic_cmpxchg_std,
317 };
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