1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __ALPHA_UACCESS_H
3#define __ALPHA_UACCESS_H
4
5/*
6 * The fs value determines whether argument validity checking should be
7 * performed or not.  If get_fs() == USER_DS, checking is performed, with
8 * get_fs() == KERNEL_DS, checking is bypassed.
9 *
10 * Or at least it did once upon a time.  Nowadays it is a mask that
11 * defines which bits of the address space are off limits.  This is a
12 * wee bit faster than the above.
13 *
14 * For historical reasons, these macros are grossly misnamed.
15 */
16
17#define KERNEL_DS	((mm_segment_t) { 0UL })
18#define USER_DS		((mm_segment_t) { -0x40000000000UL })
19
20#define get_fs()  (current_thread_info()->addr_limit)
21#define set_fs(x) (current_thread_info()->addr_limit = (x))
22
23#define uaccess_kernel()	(get_fs().seg == KERNEL_DS.seg)
24
25/*
26 * Is a address valid? This does a straightforward calculation rather
27 * than tests.
28 *
29 * Address valid if:
30 *  - "addr" doesn't have any high-bits set
31 *  - AND "size" doesn't have any high-bits set
32 *  - AND "addr+size-(size != 0)" doesn't have any high-bits set
33 *  - OR we are in kernel mode.
34 */
35#define __access_ok(addr, size) ({				\
36	unsigned long __ao_a = (addr), __ao_b = (size);		\
37	unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b;	\
38	(get_fs().seg & (__ao_a | __ao_b | __ao_end)) == 0; })
39
40#define access_ok(addr, size)				\
41({							\
42	__chk_user_ptr(addr);				\
43	__access_ok(((unsigned long)(addr)), (size));	\
44})
45
46/*
47 * These are the main single-value transfer routines.  They automatically
48 * use the right size if we just have the right pointer type.
49 *
50 * As the alpha uses the same address space for kernel and user
51 * data, we can just do these as direct assignments.  (Of course, the
52 * exception handling means that it's no longer "just"...)
53 *
54 * Careful to not
55 * (a) re-use the arguments for side effects (sizeof/typeof is ok)
56 * (b) require any knowledge of processes at this stage
57 */
58#define put_user(x, ptr) \
59  __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
60#define get_user(x, ptr) \
61  __get_user_check((x), (ptr), sizeof(*(ptr)))
62
63/*
64 * The "__xxx" versions do not do address space checking, useful when
65 * doing multiple accesses to the same area (the programmer has to do the
66 * checks by hand with "access_ok()")
67 */
68#define __put_user(x, ptr) \
69  __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
70#define __get_user(x, ptr) \
71  __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
72
73/*
74 * The "lda %1, 2b-1b(%0)" bits are magic to get the assembler to
75 * encode the bits we need for resolving the exception.  See the
76 * more extensive comments with fixup_inline_exception below for
77 * more information.
78 */
79#define EXC(label,cont,res,err)				\
80	".section __ex_table,\"a\"\n"			\
81	"	.long "#label"-.\n"			\
82	"	lda "#res","#cont"-"#label"("#err")\n"	\
83	".previous\n"
84
85extern void __get_user_unknown(void);
86
87#define __get_user_nocheck(x, ptr, size)			\
88({								\
89	long __gu_err = 0;					\
90	unsigned long __gu_val;					\
91	__chk_user_ptr(ptr);					\
92	switch (size) {						\
93	  case 1: __get_user_8(ptr); break;			\
94	  case 2: __get_user_16(ptr); break;			\
95	  case 4: __get_user_32(ptr); break;			\
96	  case 8: __get_user_64(ptr); break;			\
97	  default: __get_user_unknown(); break;			\
98	}							\
99	(x) = (__force __typeof__(*(ptr))) __gu_val;		\
100	__gu_err;						\
101})
102
103#define __get_user_check(x, ptr, size)				\
104({								\
105	long __gu_err = -EFAULT;				\
106	unsigned long __gu_val = 0;				\
107	const __typeof__(*(ptr)) __user *__gu_addr = (ptr);	\
108	if (__access_ok((unsigned long)__gu_addr, size)) {	\
109		__gu_err = 0;					\
110		switch (size) {					\
111		  case 1: __get_user_8(__gu_addr); break;	\
112		  case 2: __get_user_16(__gu_addr); break;	\
113		  case 4: __get_user_32(__gu_addr); break;	\
114		  case 8: __get_user_64(__gu_addr); break;	\
115		  default: __get_user_unknown(); break;		\
116		}						\
117	}							\
118	(x) = (__force __typeof__(*(ptr))) __gu_val;		\
119	__gu_err;						\
120})
121
122struct __large_struct { unsigned long buf[100]; };
123#define __m(x) (*(struct __large_struct __user *)(x))
124
125#define __get_user_64(addr)				\
126	__asm__("1: ldq %0,%2\n"			\
127	"2:\n"						\
128	EXC(1b,2b,%0,%1)				\
129		: "=r"(__gu_val), "=r"(__gu_err)	\
130		: "m"(__m(addr)), "1"(__gu_err))
131
132#define __get_user_32(addr)				\
133	__asm__("1: ldl %0,%2\n"			\
134	"2:\n"						\
135	EXC(1b,2b,%0,%1)				\
136		: "=r"(__gu_val), "=r"(__gu_err)	\
137		: "m"(__m(addr)), "1"(__gu_err))
138
139#ifdef __alpha_bwx__
140/* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
141
142#define __get_user_16(addr)				\
143	__asm__("1: ldwu %0,%2\n"			\
144	"2:\n"						\
145	EXC(1b,2b,%0,%1)				\
146		: "=r"(__gu_val), "=r"(__gu_err)	\
147		: "m"(__m(addr)), "1"(__gu_err))
148
149#define __get_user_8(addr)				\
150	__asm__("1: ldbu %0,%2\n"			\
151	"2:\n"						\
152	EXC(1b,2b,%0,%1)				\
153		: "=r"(__gu_val), "=r"(__gu_err)	\
154		: "m"(__m(addr)), "1"(__gu_err))
155#else
156/* Unfortunately, we can't get an unaligned access trap for the sub-word
157   load, so we have to do a general unaligned operation.  */
158
159#define __get_user_16(addr)						\
160{									\
161	long __gu_tmp;							\
162	__asm__("1: ldq_u %0,0(%3)\n"					\
163	"2:	ldq_u %1,1(%3)\n"					\
164	"	extwl %0,%3,%0\n"					\
165	"	extwh %1,%3,%1\n"					\
166	"	or %0,%1,%0\n"						\
167	"3:\n"								\
168	EXC(1b,3b,%0,%2)						\
169	EXC(2b,3b,%0,%2)						\
170		: "=&r"(__gu_val), "=&r"(__gu_tmp), "=r"(__gu_err)	\
171		: "r"(addr), "2"(__gu_err));				\
172}
173
174#define __get_user_8(addr)						\
175	__asm__("1: ldq_u %0,0(%2)\n"					\
176	"	extbl %0,%2,%0\n"					\
177	"2:\n"								\
178	EXC(1b,2b,%0,%1)						\
179		: "=&r"(__gu_val), "=r"(__gu_err)			\
180		: "r"(addr), "1"(__gu_err))
181#endif
182
183extern void __put_user_unknown(void);
184
185#define __put_user_nocheck(x, ptr, size)			\
186({								\
187	long __pu_err = 0;					\
188	__chk_user_ptr(ptr);					\
189	switch (size) {						\
190	  case 1: __put_user_8(x, ptr); break;			\
191	  case 2: __put_user_16(x, ptr); break;			\
192	  case 4: __put_user_32(x, ptr); break;			\
193	  case 8: __put_user_64(x, ptr); break;			\
194	  default: __put_user_unknown(); break;			\
195	}							\
196	__pu_err;						\
197})
198
199#define __put_user_check(x, ptr, size)				\
200({								\
201	long __pu_err = -EFAULT;				\
202	__typeof__(*(ptr)) __user *__pu_addr = (ptr);		\
203	if (__access_ok((unsigned long)__pu_addr, size)) {	\
204		__pu_err = 0;					\
205		switch (size) {					\
206		  case 1: __put_user_8(x, __pu_addr); break;	\
207		  case 2: __put_user_16(x, __pu_addr); break;	\
208		  case 4: __put_user_32(x, __pu_addr); break;	\
209		  case 8: __put_user_64(x, __pu_addr); break;	\
210		  default: __put_user_unknown(); break;		\
211		}						\
212	}							\
213	__pu_err;						\
214})
215
216/*
217 * The "__put_user_xx()" macros tell gcc they read from memory
218 * instead of writing: this is because they do not write to
219 * any memory gcc knows about, so there are no aliasing issues
220 */
221#define __put_user_64(x, addr)					\
222__asm__ __volatile__("1: stq %r2,%1\n"				\
223	"2:\n"							\
224	EXC(1b,2b,$31,%0)					\
225		: "=r"(__pu_err)				\
226		: "m" (__m(addr)), "rJ" (x), "0"(__pu_err))
227
228#define __put_user_32(x, addr)					\
229__asm__ __volatile__("1: stl %r2,%1\n"				\
230	"2:\n"							\
231	EXC(1b,2b,$31,%0)					\
232		: "=r"(__pu_err)				\
233		: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
234
235#ifdef __alpha_bwx__
236/* Those lucky bastards with ev56 and later CPUs can do byte/word moves.  */
237
238#define __put_user_16(x, addr)					\
239__asm__ __volatile__("1: stw %r2,%1\n"				\
240	"2:\n"							\
241	EXC(1b,2b,$31,%0)					\
242		: "=r"(__pu_err)				\
243		: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
244
245#define __put_user_8(x, addr)					\
246__asm__ __volatile__("1: stb %r2,%1\n"				\
247	"2:\n"							\
248	EXC(1b,2b,$31,%0)					\
249		: "=r"(__pu_err)				\
250		: "m"(__m(addr)), "rJ"(x), "0"(__pu_err))
251#else
252/* Unfortunately, we can't get an unaligned access trap for the sub-word
253   write, so we have to do a general unaligned operation.  */
254
255#define __put_user_16(x, addr)					\
256{								\
257	long __pu_tmp1, __pu_tmp2, __pu_tmp3, __pu_tmp4;	\
258	__asm__ __volatile__(					\
259	"1:	ldq_u %2,1(%5)\n"				\
260	"2:	ldq_u %1,0(%5)\n"				\
261	"	inswh %6,%5,%4\n"				\
262	"	inswl %6,%5,%3\n"				\
263	"	mskwh %2,%5,%2\n"				\
264	"	mskwl %1,%5,%1\n"				\
265	"	or %2,%4,%2\n"					\
266	"	or %1,%3,%1\n"					\
267	"3:	stq_u %2,1(%5)\n"				\
268	"4:	stq_u %1,0(%5)\n"				\
269	"5:\n"							\
270	EXC(1b,5b,$31,%0)					\
271	EXC(2b,5b,$31,%0)					\
272	EXC(3b,5b,$31,%0)					\
273	EXC(4b,5b,$31,%0)					\
274		: "=r"(__pu_err), "=&r"(__pu_tmp1), 		\
275		  "=&r"(__pu_tmp2), "=&r"(__pu_tmp3), 		\
276		  "=&r"(__pu_tmp4)				\
277		: "r"(addr), "r"((unsigned long)(x)), "0"(__pu_err)); \
278}
279
280#define __put_user_8(x, addr)					\
281{								\
282	long __pu_tmp1, __pu_tmp2;				\
283	__asm__ __volatile__(					\
284	"1:	ldq_u %1,0(%4)\n"				\
285	"	insbl %3,%4,%2\n"				\
286	"	mskbl %1,%4,%1\n"				\
287	"	or %1,%2,%1\n"					\
288	"2:	stq_u %1,0(%4)\n"				\
289	"3:\n"							\
290	EXC(1b,3b,$31,%0)					\
291	EXC(2b,3b,$31,%0)					\
292		: "=r"(__pu_err), 				\
293	  	  "=&r"(__pu_tmp1), "=&r"(__pu_tmp2)		\
294		: "r"((unsigned long)(x)), "r"(addr), "0"(__pu_err)); \
295}
296#endif
297
298
299/*
300 * Complex access routines
301 */
302
303extern long __copy_user(void *to, const void *from, long len);
304
305static inline unsigned long
306raw_copy_from_user(void *to, const void __user *from, unsigned long len)
307{
308	return __copy_user(to, (__force const void *)from, len);
309}
310
311static inline unsigned long
312raw_copy_to_user(void __user *to, const void *from, unsigned long len)
313{
314	return __copy_user((__force void *)to, from, len);
315}
316
317extern long __clear_user(void __user *to, long len);
318
319extern inline long
320clear_user(void __user *to, long len)
321{
322	if (__access_ok((unsigned long)to, len))
323		len = __clear_user(to, len);
324	return len;
325}
326
327#define user_addr_max() \
328        (uaccess_kernel() ? ~0UL : TASK_SIZE)
329
330extern long strncpy_from_user(char *dest, const char __user *src, long count);
331extern __must_check long strnlen_user(const char __user *str, long n);
332
333#include <asm/extable.h>
334
335#endif /* __ALPHA_UACCESS_H */
336