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SUNRPC: Fix oops when trace sunrpc_task events in nfs client
[linux/fpc-iii.git] / arch / s390 / lib / uaccess_pt.c
blob61ebcc9ccb3472abe320fd8ed4939b4cc5074ebe
1 /*
2 * User access functions based on page table walks for enhanced
3 * system layout without hardware support.
4 *
5 * Copyright IBM Corp. 2006, 2012
6 * Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
7 */
8
9 #include <linux/errno.h>
10 #include <linux/hardirq.h>
11 #include <linux/mm.h>
12 #include <linux/hugetlb.h>
13 #include <asm/uaccess.h>
14 #include <asm/futex.h>
15 #include "uaccess.h"
16
17 #ifndef CONFIG_64BIT
18 #define AHI "ahi"
19 #define SLR "slr"
20 #else
21 #define AHI "aghi"
22 #define SLR "slgr"
23 #endif
24
25 static size_t strnlen_kernel(size_t count, const char __user *src)
26 {
27 register unsigned long reg0 asm("0") = 0UL;
28 unsigned long tmp1, tmp2;
29
30 asm volatile(
31 " la %2,0(%1)\n"
32 " la %3,0(%0,%1)\n"
33 " "SLR" %0,%0\n"
34 "0: srst %3,%2\n"
35 " jo 0b\n"
36 " la %0,1(%3)\n" /* strnlen_kernel results includes \0 */
37 " "SLR" %0,%1\n"
38 "1:\n"
39 EX_TABLE(0b,1b)
40 : "+a" (count), "+a" (src), "=a" (tmp1), "=a" (tmp2)
41 : "d" (reg0) : "cc", "memory");
42 return count;
43 }
44
45 static size_t copy_in_kernel(size_t count, void __user *to,
46 const void __user *from)
47 {
48 unsigned long tmp1;
49
50 asm volatile(
51 " "AHI" %0,-1\n"
52 " jo 5f\n"
53 " bras %3,3f\n"
54 "0:"AHI" %0,257\n"
55 "1: mvc 0(1,%1),0(%2)\n"
56 " la %1,1(%1)\n"
57 " la %2,1(%2)\n"
58 " "AHI" %0,-1\n"
59 " jnz 1b\n"
60 " j 5f\n"
61 "2: mvc 0(256,%1),0(%2)\n"
62 " la %1,256(%1)\n"
63 " la %2,256(%2)\n"
64 "3:"AHI" %0,-256\n"
65 " jnm 2b\n"
66 "4: ex %0,1b-0b(%3)\n"
67 "5:"SLR" %0,%0\n"
68 "6:\n"
69 EX_TABLE(1b,6b) EX_TABLE(2b,0b) EX_TABLE(4b,0b)
70 : "+a" (count), "+a" (to), "+a" (from), "=a" (tmp1)
71 : : "cc", "memory");
72 return count;
73 }
74
75 /*
76 * Returns kernel address for user virtual address. If the returned address is
77 * >= -4095 (IS_ERR_VALUE(x) returns true), a fault has occurred and the
78 * address contains the (negative) exception code.
79 */
80 #ifdef CONFIG_64BIT
81
82 static unsigned long follow_table(struct mm_struct *mm,
83 unsigned long address, int write)
84 {
85 unsigned long *table = (unsigned long *)__pa(mm->pgd);
86
87 if (unlikely(address > mm->context.asce_limit - 1))
88 return -0x38UL;
89 switch (mm->context.asce_bits & _ASCE_TYPE_MASK) {
90 case _ASCE_TYPE_REGION1:
91 table = table + ((address >> 53) & 0x7ff);
92 if (unlikely(*table & _REGION_ENTRY_INVALID))
93 return -0x39UL;
94 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
95 /* fallthrough */
96 case _ASCE_TYPE_REGION2:
97 table = table + ((address >> 42) & 0x7ff);
98 if (unlikely(*table & _REGION_ENTRY_INVALID))
99 return -0x3aUL;
100 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
101 /* fallthrough */
102 case _ASCE_TYPE_REGION3:
103 table = table + ((address >> 31) & 0x7ff);
104 if (unlikely(*table & _REGION_ENTRY_INVALID))
105 return -0x3bUL;
106 table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN);
107 /* fallthrough */
108 case _ASCE_TYPE_SEGMENT:
109 table = table + ((address >> 20) & 0x7ff);
110 if (unlikely(*table & _SEGMENT_ENTRY_INVALID))
111 return -0x10UL;
112 if (unlikely(*table & _SEGMENT_ENTRY_LARGE)) {
113 if (write && (*table & _SEGMENT_ENTRY_PROTECT))
114 return -0x04UL;
115 return (*table & _SEGMENT_ENTRY_ORIGIN_LARGE) +
116 (address & ~_SEGMENT_ENTRY_ORIGIN_LARGE);
117 }
118 table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);
119 }
120 table = table + ((address >> 12) & 0xff);
121 if (unlikely(*table & _PAGE_INVALID))
122 return -0x11UL;
123 if (write && (*table & _PAGE_PROTECT))
124 return -0x04UL;
125 return (*table & PAGE_MASK) + (address & ~PAGE_MASK);
126 }
127
128 #else /* CONFIG_64BIT */
129
130 static unsigned long follow_table(struct mm_struct *mm,
131 unsigned long address, int write)
132 {
133 unsigned long *table = (unsigned long *)__pa(mm->pgd);
134
135 table = table + ((address >> 20) & 0x7ff);
136 if (unlikely(*table & _SEGMENT_ENTRY_INVALID))
137 return -0x10UL;
138 table = (unsigned long *)(*table & _SEGMENT_ENTRY_ORIGIN);
139 table = table + ((address >> 12) & 0xff);
140 if (unlikely(*table & _PAGE_INVALID))
141 return -0x11UL;
142 if (write && (*table & _PAGE_PROTECT))
143 return -0x04UL;
144 return (*table & PAGE_MASK) + (address & ~PAGE_MASK);
145 }
146
147 #endif /* CONFIG_64BIT */
148
149 static __always_inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
150 size_t n, int write_user)
151 {
152 struct mm_struct *mm = current->mm;
153 unsigned long offset, done, size, kaddr;
154 void *from, *to;
155
156 if (!mm)
157 return n;
158 done = 0;
159 retry:
160 spin_lock(&mm->page_table_lock);
161 do {
162 kaddr = follow_table(mm, uaddr, write_user);
163 if (IS_ERR_VALUE(kaddr))
164 goto fault;
165
166 offset = uaddr & ~PAGE_MASK;
167 size = min(n - done, PAGE_SIZE - offset);
168 if (write_user) {
169 to = (void *) kaddr;
170 from = kptr + done;
171 } else {
172 from = (void *) kaddr;
173 to = kptr + done;
174 }
175 memcpy(to, from, size);
176 done += size;
177 uaddr += size;
178 } while (done < n);
179 spin_unlock(&mm->page_table_lock);
180 return n - done;
181 fault:
182 spin_unlock(&mm->page_table_lock);
183 if (__handle_fault(uaddr, -kaddr, write_user))
184 return n - done;
185 goto retry;
186 }
187
188 /*
189 * Do DAT for user address by page table walk, return kernel address.
190 * This function needs to be called with current->mm->page_table_lock held.
191 */
192 static __always_inline unsigned long __dat_user_addr(unsigned long uaddr,
193 int write)
194 {
195 struct mm_struct *mm = current->mm;
196 unsigned long kaddr;
197 int rc;
198
199 retry:
200 kaddr = follow_table(mm, uaddr, write);
201 if (IS_ERR_VALUE(kaddr))
202 goto fault;
203
204 return kaddr;
205 fault:
206 spin_unlock(&mm->page_table_lock);
207 rc = __handle_fault(uaddr, -kaddr, write);
208 spin_lock(&mm->page_table_lock);
209 if (!rc)
210 goto retry;
211 return 0;
212 }
213
214 static size_t copy_from_user_pt(size_t n, const void __user *from, void *to)
215 {
216 size_t rc;
217
218 if (segment_eq(get_fs(), KERNEL_DS))
219 return copy_in_kernel(n, (void __user *) to, from);
220 rc = __user_copy_pt((unsigned long) from, to, n, 0);
221 if (unlikely(rc))
222 memset(to + n - rc, 0, rc);
223 return rc;
224 }
225
226 static size_t copy_to_user_pt(size_t n, void __user *to, const void *from)
227 {
228 if (segment_eq(get_fs(), KERNEL_DS))
229 return copy_in_kernel(n, to, (void __user *) from);
230 return __user_copy_pt((unsigned long) to, (void *) from, n, 1);
231 }
232
233 static size_t clear_user_pt(size_t n, void __user *to)
234 {
235 void *zpage = (void *) empty_zero_page;
236 long done, size, ret;
237
238 done = 0;
239 do {
240 if (n - done > PAGE_SIZE)
241 size = PAGE_SIZE;
242 else
243 size = n - done;
244 if (segment_eq(get_fs(), KERNEL_DS))
245 ret = copy_in_kernel(n, to, (void __user *) zpage);
246 else
247 ret = __user_copy_pt((unsigned long) to, zpage, size, 1);
248 done += size;
249 to += size;
250 if (ret)
251 return ret + n - done;
252 } while (done < n);
253 return 0;
254 }
255
256 static size_t strnlen_user_pt(size_t count, const char __user *src)
257 {
258 unsigned long uaddr = (unsigned long) src;
259 struct mm_struct *mm = current->mm;
260 unsigned long offset, done, len, kaddr;
261 size_t len_str;
262
263 if (unlikely(!count))
264 return 0;
265 if (segment_eq(get_fs(), KERNEL_DS))
266 return strnlen_kernel(count, src);
267 if (!mm)
268 return 0;
269 done = 0;
270 retry:
271 spin_lock(&mm->page_table_lock);
272 do {
273 kaddr = follow_table(mm, uaddr, 0);
274 if (IS_ERR_VALUE(kaddr))
275 goto fault;
276
277 offset = uaddr & ~PAGE_MASK;
278 len = min(count - done, PAGE_SIZE - offset);
279 len_str = strnlen((char *) kaddr, len);
280 done += len_str;
281 uaddr += len_str;
282 } while ((len_str == len) && (done < count));
283 spin_unlock(&mm->page_table_lock);
284 return done + 1;
285 fault:
286 spin_unlock(&mm->page_table_lock);
287 if (__handle_fault(uaddr, -kaddr, 0))
288 return 0;
289 goto retry;
290 }
291
292 static size_t strncpy_from_user_pt(size_t count, const char __user *src,
293 char *dst)
294 {
295 size_t done, len, offset, len_str;
296
297 if (unlikely(!count))
298 return 0;
299 done = 0;
300 do {
301 offset = (size_t)src & ~PAGE_MASK;
302 len = min(count - done, PAGE_SIZE - offset);
303 if (segment_eq(get_fs(), KERNEL_DS)) {
304 if (copy_in_kernel(len, (void __user *) dst, src))
305 return -EFAULT;
306 } else {
307 if (__user_copy_pt((unsigned long) src, dst, len, 0))
308 return -EFAULT;
309 }
310 len_str = strnlen(dst, len);
311 done += len_str;
312 src += len_str;
313 dst += len_str;
314 } while ((len_str == len) && (done < count));
315 return done;
316 }
317
318 static size_t copy_in_user_pt(size_t n, void __user *to,
319 const void __user *from)
320 {
321 struct mm_struct *mm = current->mm;
322 unsigned long offset_max, uaddr, done, size, error_code;
323 unsigned long uaddr_from = (unsigned long) from;
324 unsigned long uaddr_to = (unsigned long) to;
325 unsigned long kaddr_to, kaddr_from;
326 int write_user;
327
328 if (segment_eq(get_fs(), KERNEL_DS))
329 return copy_in_kernel(n, to, from);
330 if (!mm)
331 return n;
332 done = 0;
333 retry:
334 spin_lock(&mm->page_table_lock);
335 do {
336 write_user = 0;
337 uaddr = uaddr_from;
338 kaddr_from = follow_table(mm, uaddr_from, 0);
339 error_code = kaddr_from;
340 if (IS_ERR_VALUE(error_code))
341 goto fault;
342
343 write_user = 1;
344 uaddr = uaddr_to;
345 kaddr_to = follow_table(mm, uaddr_to, 1);
346 error_code = (unsigned long) kaddr_to;
347 if (IS_ERR_VALUE(error_code))
348 goto fault;
349
350 offset_max = max(uaddr_from & ~PAGE_MASK,
351 uaddr_to & ~PAGE_MASK);
352 size = min(n - done, PAGE_SIZE - offset_max);
353
354 memcpy((void *) kaddr_to, (void *) kaddr_from, size);
355 done += size;
356 uaddr_from += size;
357 uaddr_to += size;
358 } while (done < n);
359 spin_unlock(&mm->page_table_lock);
360 return n - done;
361 fault:
362 spin_unlock(&mm->page_table_lock);
363 if (__handle_fault(uaddr, -error_code, write_user))
364 return n - done;
365 goto retry;
366 }
367
368 #define __futex_atomic_op(insn, ret, oldval, newval, uaddr, oparg) \
369 asm volatile("0: l %1,0(%6)\n" \
370 "1: " insn \
371 "2: cs %1,%2,0(%6)\n" \
372 "3: jl 1b\n" \
373 " lhi %0,0\n" \
374 "4:\n" \
375 EX_TABLE(0b,4b) EX_TABLE(2b,4b) EX_TABLE(3b,4b) \
376 : "=d" (ret), "=&d" (oldval), "=&d" (newval), \
377 "=m" (*uaddr) \
378 : "0" (-EFAULT), "d" (oparg), "a" (uaddr), \
379 "m" (*uaddr) : "cc" );
380
381 static int __futex_atomic_op_pt(int op, u32 __user *uaddr, int oparg, int *old)
382 {
383 int oldval = 0, newval, ret;
384
385 switch (op) {
386 case FUTEX_OP_SET:
387 __futex_atomic_op("lr %2,%5\n",
388 ret, oldval, newval, uaddr, oparg);
389 break;
390 case FUTEX_OP_ADD:
391 __futex_atomic_op("lr %2,%1\nar %2,%5\n",
392 ret, oldval, newval, uaddr, oparg);
393 break;
394 case FUTEX_OP_OR:
395 __futex_atomic_op("lr %2,%1\nor %2,%5\n",
396 ret, oldval, newval, uaddr, oparg);
397 break;
398 case FUTEX_OP_ANDN:
399 __futex_atomic_op("lr %2,%1\nnr %2,%5\n",
400 ret, oldval, newval, uaddr, oparg);
401 break;
402 case FUTEX_OP_XOR:
403 __futex_atomic_op("lr %2,%1\nxr %2,%5\n",
404 ret, oldval, newval, uaddr, oparg);
405 break;
406 default:
407 ret = -ENOSYS;
408 }
409 if (ret == 0)
410 *old = oldval;
411 return ret;
412 }
413
414 int futex_atomic_op_pt(int op, u32 __user *uaddr, int oparg, int *old)
415 {
416 int ret;
417
418 if (segment_eq(get_fs(), KERNEL_DS))
419 return __futex_atomic_op_pt(op, uaddr, oparg, old);
420 if (unlikely(!current->mm))
421 return -EFAULT;
422 spin_lock(&current->mm->page_table_lock);
423 uaddr = (u32 __force __user *)
424 __dat_user_addr((__force unsigned long) uaddr, 1);
425 if (!uaddr) {
426 spin_unlock(&current->mm->page_table_lock);
427 return -EFAULT;
428 }
429 get_page(virt_to_page(uaddr));
430 spin_unlock(&current->mm->page_table_lock);
431 ret = __futex_atomic_op_pt(op, uaddr, oparg, old);
432 put_page(virt_to_page(uaddr));
433 return ret;
434 }
435
436 static int __futex_atomic_cmpxchg_pt(u32 *uval, u32 __user *uaddr,
437 u32 oldval, u32 newval)
438 {
439 int ret;
440
441 asm volatile("0: cs %1,%4,0(%5)\n"
442 "1: la %0,0\n"
443 "2:\n"
444 EX_TABLE(0b,2b) EX_TABLE(1b,2b)
445 : "=d" (ret), "+d" (oldval), "=m" (*uaddr)
446 : "0" (-EFAULT), "d" (newval), "a" (uaddr), "m" (*uaddr)
447 : "cc", "memory" );
448 *uval = oldval;
449 return ret;
450 }
451
452 int futex_atomic_cmpxchg_pt(u32 *uval, u32 __user *uaddr,
453 u32 oldval, u32 newval)
454 {
455 int ret;
456
457 if (segment_eq(get_fs(), KERNEL_DS))
458 return __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
459 if (unlikely(!current->mm))
460 return -EFAULT;
461 spin_lock(&current->mm->page_table_lock);
462 uaddr = (u32 __force __user *)
463 __dat_user_addr((__force unsigned long) uaddr, 1);
464 if (!uaddr) {
465 spin_unlock(&current->mm->page_table_lock);
466 return -EFAULT;
467 }
468 get_page(virt_to_page(uaddr));
469 spin_unlock(&current->mm->page_table_lock);
470 ret = __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
471 put_page(virt_to_page(uaddr));
472 return ret;
473 }
474
475 struct uaccess_ops uaccess_pt = {
476 .copy_from_user = copy_from_user_pt,
477 .copy_to_user = copy_to_user_pt,
478 .copy_in_user = copy_in_user_pt,
479 .clear_user = clear_user_pt,
480 .strnlen_user = strnlen_user_pt,
481 .strncpy_from_user = strncpy_from_user_pt,
482 .futex_atomic_op = futex_atomic_op_pt,
483 .futex_atomic_cmpxchg = futex_atomic_cmpxchg_pt,
484 };
Linux with added FPC-III support