1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
7 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
8 * Copyright (C) 2007  Maciej W. Rozycki
9 * Copyright (C) 2014, Imagination Technologies Ltd.
10 */
11#ifndef _ASM_UACCESS_H
12#define _ASM_UACCESS_H
13
14#include <linux/kernel.h>
15#include <linux/string.h>
16#include <asm/asm-eva.h>
17#include <asm/extable.h>
18
19#ifdef CONFIG_32BIT
20
21#define __UA_LIMIT 0x80000000UL
22#define TASK_SIZE_MAX	KSEG0
23
24#define __UA_ADDR	".word"
25#define __UA_LA		"la"
26#define __UA_ADDU	"addu"
27#define __UA_t0		"$8"
28#define __UA_t1		"$9"
29
30#endif /* CONFIG_32BIT */
31
32#ifdef CONFIG_64BIT
33
34extern u64 __ua_limit;
35
36#define __UA_LIMIT	__ua_limit
37#define TASK_SIZE_MAX	XKSSEG
38
39#define __UA_ADDR	".dword"
40#define __UA_LA		"dla"
41#define __UA_ADDU	"daddu"
42#define __UA_t0		"$12"
43#define __UA_t1		"$13"
44
45#endif /* CONFIG_64BIT */
46
47#include <asm-generic/access_ok.h>
48
49/*
50 * put_user: - Write a simple value into user space.
51 * @x:	 Value to copy to user space.
52 * @ptr: Destination address, in user space.
53 *
54 * Context: User context only. This function may sleep if pagefaults are
55 *          enabled.
56 *
57 * This macro copies a single simple value from kernel space to user
58 * space.  It supports simple types like char and int, but not larger
59 * data types like structures or arrays.
60 *
61 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
62 * to the result of dereferencing @ptr.
63 *
64 * Returns zero on success, or -EFAULT on error.
65 */
66#define put_user(x, ptr)						\
67({									\
68	__typeof__(*(ptr)) __user *__p = (ptr);				\
69									\
70	might_fault();							\
71	access_ok(__p, sizeof(*__p)) ? __put_user((x), __p) : -EFAULT;	\
72})
73
74/*
75 * get_user: - Get a simple variable from user space.
76 * @x:	 Variable to store result.
77 * @ptr: Source address, in user space.
78 *
79 * Context: User context only. This function may sleep if pagefaults are
80 *          enabled.
81 *
82 * This macro copies a single simple variable from user space to kernel
83 * space.  It supports simple types like char and int, but not larger
84 * data types like structures or arrays.
85 *
86 * @ptr must have pointer-to-simple-variable type, and the result of
87 * dereferencing @ptr must be assignable to @x without a cast.
88 *
89 * Returns zero on success, or -EFAULT on error.
90 * On error, the variable @x is set to zero.
91 */
92#define get_user(x, ptr)						\
93({									\
94	const __typeof__(*(ptr)) __user *__p = (ptr);			\
95									\
96	might_fault();							\
97	access_ok(__p, sizeof(*__p)) ? __get_user((x), __p) :		\
98				       ((x) = 0, -EFAULT);		\
99})
100
101/*
102 * __put_user: - Write a simple value into user space, with less checking.
103 * @x:	 Value to copy to user space.
104 * @ptr: Destination address, in user space.
105 *
106 * Context: User context only. This function may sleep if pagefaults are
107 *          enabled.
108 *
109 * This macro copies a single simple value from kernel space to user
110 * space.  It supports simple types like char and int, but not larger
111 * data types like structures or arrays.
112 *
113 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
114 * to the result of dereferencing @ptr.
115 *
116 * Caller must check the pointer with access_ok() before calling this
117 * function.
118 *
119 * Returns zero on success, or -EFAULT on error.
120 */
121#define __put_user(x, ptr)						\
122({									\
123	__typeof__(*(ptr)) __user *__pu_ptr = (ptr);			\
124	__typeof__(*(ptr)) __pu_val = (x);				\
125	int __pu_err = 0;						\
126									\
127	__chk_user_ptr(__pu_ptr);					\
128	switch (sizeof(*__pu_ptr)) {					\
129	case 1:								\
130		__put_data_asm(user_sb, __pu_ptr);			\
131		break;							\
132	case 2:								\
133		__put_data_asm(user_sh, __pu_ptr);			\
134		break;							\
135	case 4:								\
136		__put_data_asm(user_sw, __pu_ptr);			\
137		break;							\
138	case 8:								\
139		__PUT_DW(user_sd, __pu_ptr);				\
140		break;							\
141	default:							\
142		BUILD_BUG();						\
143	}								\
144									\
145	__pu_err;							\
146})
147
148/*
149 * __get_user: - Get a simple variable from user space, with less checking.
150 * @x:	 Variable to store result.
151 * @ptr: Source address, in user space.
152 *
153 * Context: User context only. This function may sleep if pagefaults are
154 *          enabled.
155 *
156 * This macro copies a single simple variable from user space to kernel
157 * space.  It supports simple types like char and int, but not larger
158 * data types like structures or arrays.
159 *
160 * @ptr must have pointer-to-simple-variable type, and the result of
161 * dereferencing @ptr must be assignable to @x without a cast.
162 *
163 * Caller must check the pointer with access_ok() before calling this
164 * function.
165 *
166 * Returns zero on success, or -EFAULT on error.
167 * On error, the variable @x is set to zero.
168 */
169#define __get_user(x, ptr)						\
170({									\
171	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
172	int __gu_err = 0;						\
173									\
174	__chk_user_ptr(__gu_ptr);					\
175	switch (sizeof(*__gu_ptr)) {					\
176	case 1:								\
177		__get_data_asm((x), user_lb, __gu_ptr);			\
178		break;							\
179	case 2:								\
180		__get_data_asm((x), user_lh, __gu_ptr);			\
181		break;							\
182	case 4:								\
183		__get_data_asm((x), user_lw, __gu_ptr);			\
184		break;							\
185	case 8:								\
186		__GET_DW((x), user_ld, __gu_ptr);			\
187		break;							\
188	default:							\
189		BUILD_BUG();						\
190	}								\
191									\
192	__gu_err;							\
193})
194
195struct __large_struct { unsigned long buf[100]; };
196#define __m(x) (*(struct __large_struct __user *)(x))
197
198#ifdef CONFIG_32BIT
199#define __GET_DW(val, insn, ptr) __get_data_asm_ll32(val, insn, ptr)
200#endif
201#ifdef CONFIG_64BIT
202#define __GET_DW(val, insn, ptr) __get_data_asm(val, insn, ptr)
203#endif
204
205#define __get_data_asm(val, insn, addr)					\
206{									\
207	long __gu_tmp;							\
208									\
209	__asm__ __volatile__(						\
210	"1:	"insn("%1", "%3")"				\n"	\
211	"2:							\n"	\
212	"	.insn						\n"	\
213	"	.section .fixup,\"ax\"				\n"	\
214	"3:	li	%0, %4					\n"	\
215	"	move	%1, $0					\n"	\
216	"	j	2b					\n"	\
217	"	.previous					\n"	\
218	"	.section __ex_table,\"a\"			\n"	\
219	"	"__UA_ADDR "\t1b, 3b				\n"	\
220	"	.previous					\n"	\
221	: "=r" (__gu_err), "=r" (__gu_tmp)				\
222	: "0" (0), "o" (__m(addr)), "i" (-EFAULT));			\
223									\
224	(val) = (__typeof__(*(addr))) __gu_tmp;				\
225}
226
227/*
228 * Get a long long 64 using 32 bit registers.
229 */
230#define __get_data_asm_ll32(val, insn, addr)				\
231{									\
232	union {								\
233		unsigned long long	l;				\
234		__typeof__(*(addr))	t;				\
235	} __gu_tmp;							\
236									\
237	__asm__ __volatile__(						\
238	"1:	" insn("%1", "(%3)")"				\n"	\
239	"2:	" insn("%D1", "4(%3)")"				\n"	\
240	"3:							\n"	\
241	"	.insn						\n"	\
242	"	.section	.fixup,\"ax\"			\n"	\
243	"4:	li	%0, %4					\n"	\
244	"	move	%1, $0					\n"	\
245	"	move	%D1, $0					\n"	\
246	"	j	3b					\n"	\
247	"	.previous					\n"	\
248	"	.section	__ex_table,\"a\"		\n"	\
249	"	" __UA_ADDR "	1b, 4b				\n"	\
250	"	" __UA_ADDR "	2b, 4b				\n"	\
251	"	.previous					\n"	\
252	: "=r" (__gu_err), "=&r" (__gu_tmp.l)				\
253	: "0" (0), "r" (addr), "i" (-EFAULT));				\
254									\
255	(val) = __gu_tmp.t;						\
256}
257
258#define __get_kernel_nofault(dst, src, type, err_label)			\
259do {									\
260	int __gu_err;							\
261									\
262	switch (sizeof(type)) {						\
263	case 1:								\
264		__get_data_asm(*(type *)(dst), kernel_lb,		\
265			       (__force type *)(src));			\
266		break;							\
267	case 2:								\
268		__get_data_asm(*(type *)(dst), kernel_lh,		\
269			       (__force type *)(src));			\
270		break;							\
271	case 4:								\
272		 __get_data_asm(*(type *)(dst), kernel_lw,		\
273			       (__force type *)(src));			\
274		break;							\
275	case 8:								\
276		__GET_DW(*(type *)(dst), kernel_ld,			\
277			 (__force type *)(src));			\
278		break;							\
279	default:							\
280		BUILD_BUG();						\
281		break;							\
282	}								\
283	if (unlikely(__gu_err))						\
284		goto err_label;						\
285} while (0)
286
287/*
288 * Yuck.  We need two variants, one for 64bit operation and one
289 * for 32 bit mode and old iron.
290 */
291#ifdef CONFIG_32BIT
292#define __PUT_DW(insn, ptr) __put_data_asm_ll32(insn, ptr)
293#endif
294#ifdef CONFIG_64BIT
295#define __PUT_DW(insn, ptr) __put_data_asm(insn, ptr)
296#endif
297
298#define __put_data_asm(insn, ptr)					\
299{									\
300	__asm__ __volatile__(						\
301	"1:	"insn("%z2", "%3")"	# __put_data_asm	\n"	\
302	"2:							\n"	\
303	"	.insn						\n"	\
304	"	.section	.fixup,\"ax\"			\n"	\
305	"3:	li	%0, %4					\n"	\
306	"	j	2b					\n"	\
307	"	.previous					\n"	\
308	"	.section	__ex_table,\"a\"		\n"	\
309	"	" __UA_ADDR "	1b, 3b				\n"	\
310	"	.previous					\n"	\
311	: "=r" (__pu_err)						\
312	: "0" (0), "Jr" (__pu_val), "o" (__m(ptr)),			\
313	  "i" (-EFAULT));						\
314}
315
316#define __put_data_asm_ll32(insn, ptr)					\
317{									\
318	__asm__ __volatile__(						\
319	"1:	"insn("%2", "(%3)")"	# __put_data_asm_ll32	\n"	\
320	"2:	"insn("%D2", "4(%3)")"				\n"	\
321	"3:							\n"	\
322	"	.insn						\n"	\
323	"	.section	.fixup,\"ax\"			\n"	\
324	"4:	li	%0, %4					\n"	\
325	"	j	3b					\n"	\
326	"	.previous					\n"	\
327	"	.section	__ex_table,\"a\"		\n"	\
328	"	" __UA_ADDR "	1b, 4b				\n"	\
329	"	" __UA_ADDR "	2b, 4b				\n"	\
330	"	.previous"						\
331	: "=r" (__pu_err)						\
332	: "0" (0), "r" (__pu_val), "r" (ptr),				\
333	  "i" (-EFAULT));						\
334}
335
336#define __put_kernel_nofault(dst, src, type, err_label)			\
337do {									\
338	type __pu_val;					\
339	int __pu_err = 0;						\
340									\
341	__pu_val = *(__force type *)(src);				\
342	switch (sizeof(type)) {						\
343	case 1:								\
344		__put_data_asm(kernel_sb, (type *)(dst));		\
345		break;							\
346	case 2:								\
347		__put_data_asm(kernel_sh, (type *)(dst));		\
348		break;							\
349	case 4:								\
350		__put_data_asm(kernel_sw, (type *)(dst))		\
351		break;							\
352	case 8:								\
353		__PUT_DW(kernel_sd, (type *)(dst));			\
354		break;							\
355	default:							\
356		BUILD_BUG();						\
357		break;							\
358	}								\
359	if (unlikely(__pu_err))						\
360		goto err_label;						\
361} while (0)
362
363
364/*
365 * We're generating jump to subroutines which will be outside the range of
366 * jump instructions
367 */
368#ifdef MODULE
369#define __MODULE_JAL(destination)					\
370	".set\tnoat\n\t"						\
371	__UA_LA "\t$1, " #destination "\n\t"				\
372	"jalr\t$1\n\t"							\
373	".set\tat\n\t"
374#else
375#define __MODULE_JAL(destination)					\
376	"jal\t" #destination "\n\t"
377#endif
378
379#if defined(CONFIG_CPU_DADDI_WORKAROUNDS) || (defined(CONFIG_EVA) &&	\
380					      defined(CONFIG_CPU_HAS_PREFETCH))
381#define DADDI_SCRATCH "$3"
382#else
383#define DADDI_SCRATCH "$0"
384#endif
385
386extern size_t __raw_copy_from_user(void *__to, const void *__from, size_t __n);
387extern size_t __raw_copy_to_user(void *__to, const void *__from, size_t __n);
388
389static inline unsigned long
390raw_copy_from_user(void *to, const void __user *from, unsigned long n)
391{
392	register void *__cu_to_r __asm__("$4");
393	register const void __user *__cu_from_r __asm__("$5");
394	register long __cu_len_r __asm__("$6");
395
396	__cu_to_r = to;
397	__cu_from_r = from;
398	__cu_len_r = n;
399
400	__asm__ __volatile__(
401		".set\tnoreorder\n\t"
402		__MODULE_JAL(__raw_copy_from_user)
403		".set\tnoat\n\t"
404		__UA_ADDU "\t$1, %1, %2\n\t"
405		".set\tat\n\t"
406		".set\treorder"
407		: "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)
408		:
409		: "$8", "$9", "$10", "$11", "$12", "$14", "$15", "$24", "$31",
410		  DADDI_SCRATCH, "memory");
411
412	return __cu_len_r;
413}
414
415static inline unsigned long
416raw_copy_to_user(void __user *to, const void *from, unsigned long n)
417{
418	register void __user *__cu_to_r __asm__("$4");
419	register const void *__cu_from_r __asm__("$5");
420	register long __cu_len_r __asm__("$6");
421
422	__cu_to_r = (to);
423	__cu_from_r = (from);
424	__cu_len_r = (n);
425
426	__asm__ __volatile__(
427		__MODULE_JAL(__raw_copy_to_user)
428		: "+r" (__cu_to_r), "+r" (__cu_from_r), "+r" (__cu_len_r)
429		:
430		: "$8", "$9", "$10", "$11", "$12", "$14", "$15", "$24", "$31",
431		  DADDI_SCRATCH, "memory");
432
433	return __cu_len_r;
434}
435
436#define INLINE_COPY_FROM_USER
437#define INLINE_COPY_TO_USER
438
439extern __kernel_size_t __bzero(void __user *addr, __kernel_size_t size);
440
441/*
442 * __clear_user: - Zero a block of memory in user space, with less checking.
443 * @to:	  Destination address, in user space.
444 * @n:	  Number of bytes to zero.
445 *
446 * Zero a block of memory in user space.  Caller must check
447 * the specified block with access_ok() before calling this function.
448 *
449 * Returns number of bytes that could not be cleared.
450 * On success, this will be zero.
451 */
452static inline __kernel_size_t
453__clear_user(void __user *addr, __kernel_size_t size)
454{
455	__kernel_size_t res;
456
457#ifdef CONFIG_CPU_MICROMIPS
458/* micromips memset / bzero also clobbers t7 & t8 */
459#define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$15", "$24", "$31"
460#else
461#define bzero_clobbers "$4", "$5", "$6", __UA_t0, __UA_t1, "$31"
462#endif /* CONFIG_CPU_MICROMIPS */
463
464	might_fault();
465	__asm__ __volatile__(
466		"move\t$4, %1\n\t"
467		"move\t$5, $0\n\t"
468		"move\t$6, %2\n\t"
469		__MODULE_JAL(__bzero)
470		"move\t%0, $6"
471		: "=r" (res)
472		: "r" (addr), "r" (size)
473		: bzero_clobbers);
474
475	return res;
476}
477
478#define clear_user(addr,n)						\
479({									\
480	void __user * __cl_addr = (addr);				\
481	unsigned long __cl_size = (n);					\
482	if (__cl_size && access_ok(__cl_addr, __cl_size))		\
483		__cl_size = __clear_user(__cl_addr, __cl_size);		\
484	__cl_size;							\
485})
486
487extern long __strncpy_from_user_asm(char *__to, const char __user *__from, long __len);
488
489/*
490 * strncpy_from_user: - Copy a NUL terminated string from userspace.
491 * @dst:   Destination address, in kernel space.  This buffer must be at
492 *	   least @count bytes long.
493 * @src:   Source address, in user space.
494 * @count: Maximum number of bytes to copy, including the trailing NUL.
495 *
496 * Copies a NUL-terminated string from userspace to kernel space.
497 *
498 * On success, returns the length of the string (not including the trailing
499 * NUL).
500 *
501 * If access to userspace fails, returns -EFAULT (some data may have been
502 * copied).
503 *
504 * If @count is smaller than the length of the string, copies @count bytes
505 * and returns @count.
506 */
507static inline long
508strncpy_from_user(char *__to, const char __user *__from, long __len)
509{
510	long res;
511
512	if (!access_ok(__from, __len))
513		return -EFAULT;
514
515	might_fault();
516	__asm__ __volatile__(
517		"move\t$4, %1\n\t"
518		"move\t$5, %2\n\t"
519		"move\t$6, %3\n\t"
520		__MODULE_JAL(__strncpy_from_user_asm)
521		"move\t%0, $2"
522		: "=r" (res)
523		: "r" (__to), "r" (__from), "r" (__len)
524		: "$2", "$3", "$4", "$5", "$6", __UA_t0, "$31", "memory");
525
526	return res;
527}
528
529extern long __strnlen_user_asm(const char __user *s, long n);
530
531/*
532 * strnlen_user: - Get the size of a string in user space.
533 * @str: The string to measure.
534 *
535 * Context: User context only. This function may sleep if pagefaults are
536 *          enabled.
537 *
538 * Get the size of a NUL-terminated string in user space.
539 *
540 * Returns the size of the string INCLUDING the terminating NUL.
541 * On exception, returns 0.
542 * If the string is too long, returns a value greater than @n.
543 */
544static inline long strnlen_user(const char __user *s, long n)
545{
546	long res;
547
548	if (!access_ok(s, 1))
549		return 0;
550
551	might_fault();
552	__asm__ __volatile__(
553		"move\t$4, %1\n\t"
554		"move\t$5, %2\n\t"
555		__MODULE_JAL(__strnlen_user_asm)
556		"move\t%0, $2"
557		: "=r" (res)
558		: "r" (s), "r" (n)
559		: "$2", "$4", "$5", __UA_t0, "$31");
560
561	return res;
562}
563
564#endif /* _ASM_UACCESS_H */
565