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2024-01-05 071106ecf68c401173c58808b1cf5f68cc50d390 
 kernel/arch/riscv/include/asm/uaccess.h
....@@ -1,14 +1,6 @@
1
+/* SPDX-License-Identifier: GPL-2.0-only */
12 /*
23  * Copyright (C) 2012 Regents of the University of California
3
- *
4
- *   This program is free software; you can redistribute it and/or
5
- *   modify it under the terms of the GNU General Public License
6
- *   as published by the Free Software Foundation, version 2.
7
- *
8
- *   This program is distributed in the hope that it will be useful,
9
- *   but WITHOUT ANY WARRANTY; without even the implied warranty of
10
- *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11
- *   GNU General Public License for more details.
124  *
135  * This file was copied from include/asm-generic/uaccess.h
146  */
....@@ -16,13 +8,17 @@
168 #ifndef _ASM_RISCV_UACCESS_H
179 #define _ASM_RISCV_UACCESS_H
1810 
11
+#include <asm/pgtable.h>		/* for TASK_SIZE */
12
+
1913 /*
2014  * User space memory access functions
2115  */
16
+#ifdef CONFIG_MMU
2217 #include <linux/errno.h>
2318 #include <linux/compiler.h>
2419 #include <linux/thread_info.h>
2520 #include <asm/byteorder.h>
21
+#include <asm/extable.h>
2622 #include <asm/asm.h>
2723 
2824 #define __enable_user_access()							\
....@@ -30,38 +26,8 @@
3026 #define __disable_user_access()							\
3127 	__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")
3228 
33
-/*
34
- * The fs value determines whether argument validity checking should be
35
- * performed or not.  If get_fs() == USER_DS, checking is performed, with
36
- * get_fs() == KERNEL_DS, checking is bypassed.
37
- *
38
- * For historical reasons, these macros are grossly misnamed.
39
- */
40
-
41
-#define KERNEL_DS	(~0UL)
42
-#define USER_DS		(TASK_SIZE)
43
-
44
-#define get_ds()	(KERNEL_DS)
45
-#define get_fs()	(current_thread_info()->addr_limit)
46
-
47
-static inline void set_fs(mm_segment_t fs)
48
-{
49
-	current_thread_info()->addr_limit = fs;
50
-}
51
-
52
-#define segment_eq(a, b) ((a) == (b))
53
-
54
-#define user_addr_max()	(get_fs())
55
-
56
-
57
-#define VERIFY_READ	0
58
-#define VERIFY_WRITE	1
59
-
6029 /**
6130  * access_ok: - Checks if a user space pointer is valid
62
- * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
63
- *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
64
- *        to write to a block, it is always safe to read from it.
6531  * @addr: User space pointer to start of block to check
6632  * @size: Size of block to check
6733  *
....@@ -76,7 +42,7 @@
7642  * checks that the pointer is in the user space range - after calling
7743  * this function, memory access functions may still return -EFAULT.
7844  */
79
-#define access_ok(type, addr, size) ({					\
45
+#define access_ok(addr, size) ({					\
8046 	__chk_user_ptr(addr);						\
8147 	likely(__access_ok((unsigned long __force)(addr), (size)));	\
8248 })
....@@ -87,9 +53,7 @@
8753  */
8854 static inline int __access_ok(unsigned long addr, unsigned long size)
8955 {
90
-	const mm_segment_t fs = get_fs();
91
-
92
-	return (size <= fs) && (addr <= (fs - size));
56
+	return size <= TASK_SIZE && addr <= TASK_SIZE - size;
9357 }
9458 
9559 /*
....@@ -105,21 +69,8 @@
10569  * on our cache or tlb entries.
10670  */
10771 
108
-struct exception_table_entry {
109
-	unsigned long insn, fixup;
110
-};
111
-
112
-extern int fixup_exception(struct pt_regs *state);
113
-
114
-#if defined(__LITTLE_ENDIAN)
115
-#define __MSW	1
11672 #define __LSW	0
117
-#elif defined(__BIG_ENDIAN)
118
-#define __MSW	0
119
-#define	__LSW	1
120
-#else
121
-#error "Unknown endianness"
122
-#endif
73
+#define __MSW	1
12374 
12475 /*
12576  * The "__xxx" versions of the user access functions do not verify the address
....@@ -131,7 +82,6 @@
13182 do {								\
13283 	uintptr_t __tmp;					\
13384 	__typeof__(x) __x;					\
134
-	__enable_user_access();					\
13585 	__asm__ __volatile__ (					\
13686 		"1:\n"						\
13787 		"	" insn " %1, %3\n"			\
....@@ -149,7 +99,6 @@
14999 		"	.previous"				\
150100 		: "+r" (err), "=&r" (__x), "=r" (__tmp)		\
151101 		: "m" (*(ptr)), "i" (-EFAULT));			\
152
-	__disable_user_access();				\
153102 	(x) = __x;						\
154103 } while (0)
155104 
....@@ -162,7 +111,6 @@
162111 	u32 __user *__ptr = (u32 __user *)(ptr);		\
163112 	u32 __lo, __hi;						\
164113 	uintptr_t __tmp;					\
165
-	__enable_user_access();					\
166114 	__asm__ __volatile__ (					\
167115 		"1:\n"						\
168116 		"	lw %1, %4\n"				\
....@@ -186,12 +134,30 @@
186134 			"=r" (__tmp)				\
187135 		: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]),	\
188136 			"i" (-EFAULT));				\
189
-	__disable_user_access();				\
190137 	(x) = (__typeof__(x))((__typeof__((x)-(x)))(		\
191138 		(((u64)__hi << 32) | __lo)));			\
192139 } while (0)
193140 #endif /* CONFIG_64BIT */
194141 
142
+#define __get_user_nocheck(x, __gu_ptr, __gu_err)		\
143
+do {								\
144
+	switch (sizeof(*__gu_ptr)) {				\
145
+	case 1:							\
146
+		__get_user_asm("lb", (x), __gu_ptr, __gu_err);	\
147
+		break;						\
148
+	case 2:							\
149
+		__get_user_asm("lh", (x), __gu_ptr, __gu_err);	\
150
+		break;						\
151
+	case 4:							\
152
+		__get_user_asm("lw", (x), __gu_ptr, __gu_err);	\
153
+		break;						\
154
+	case 8:							\
155
+		__get_user_8((x), __gu_ptr, __gu_err);	\
156
+		break;						\
157
+	default:						\
158
+		BUILD_BUG();					\
159
+	}							\
160
+} while (0)
195161 
196162 /**
197163  * __get_user: - Get a simple variable from user space, with less checking.
....@@ -215,25 +181,15 @@
215181  */
216182 #define __get_user(x, ptr)					\
217183 ({								\
218
-	register long __gu_err = 0;				\
219184 	const __typeof__(*(ptr)) __user *__gu_ptr = (ptr);	\
185
+	long __gu_err = 0;					\
186
+								\
220187 	__chk_user_ptr(__gu_ptr);				\
221
-	switch (sizeof(*__gu_ptr)) {				\
222
-	case 1:							\
223
-		__get_user_asm("lb", (x), __gu_ptr, __gu_err);	\
224
-		break;						\
225
-	case 2:							\
226
-		__get_user_asm("lh", (x), __gu_ptr, __gu_err);	\
227
-		break;						\
228
-	case 4:							\
229
-		__get_user_asm("lw", (x), __gu_ptr, __gu_err);	\
230
-		break;						\
231
-	case 8:							\
232
-		__get_user_8((x), __gu_ptr, __gu_err);	\
233
-		break;						\
234
-	default:						\
235
-		BUILD_BUG();					\
236
-	}							\
188
+								\
189
+	__enable_user_access();					\
190
+	__get_user_nocheck(x, __gu_ptr, __gu_err);		\
191
+	__disable_user_access();				\
192
+								\
237193 	__gu_err;						\
238194 })
239195 
....@@ -258,16 +214,15 @@
258214 ({								\
259215 	const __typeof__(*(ptr)) __user *__p = (ptr);		\
260216 	might_fault();						\
261
-	access_ok(VERIFY_READ, __p, sizeof(*__p)) ?		\
217
+	access_ok(__p, sizeof(*__p)) ?		\
262218 		__get_user((x), __p) :				\
263
-		((x) = 0, -EFAULT);				\
219
+		((x) = (__force __typeof__(x))0, -EFAULT);	\
264220 })
265221 
266222 #define __put_user_asm(insn, x, ptr, err)			\
267223 do {								\
268224 	uintptr_t __tmp;					\
269225 	__typeof__(*(ptr)) __x = x;				\
270
-	__enable_user_access();					\
271226 	__asm__ __volatile__ (					\
272227 		"1:\n"						\
273228 		"	" insn " %z3, %2\n"			\
....@@ -284,7 +239,6 @@
284239 		"	.previous"				\
285240 		: "+r" (err), "=r" (__tmp), "=m" (*(ptr))	\
286241 		: "rJ" (__x), "i" (-EFAULT));			\
287
-	__disable_user_access();				\
288242 } while (0)
289243 
290244 #ifdef CONFIG_64BIT
....@@ -296,7 +250,6 @@
296250 	u32 __user *__ptr = (u32 __user *)(ptr);		\
297251 	u64 __x = (__typeof__((x)-(x)))(x);			\
298252 	uintptr_t __tmp;					\
299
-	__enable_user_access();					\
300253 	__asm__ __volatile__ (					\
301254 		"1:\n"						\
302255 		"	sw %z4, %2\n"				\
....@@ -318,35 +271,11 @@
318271 			"=m" (__ptr[__LSW]),			\
319272 			"=m" (__ptr[__MSW])			\
320273 		: "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT));	\
321
-	__disable_user_access();				\
322274 } while (0)
323275 #endif /* CONFIG_64BIT */
324276 
325
-
326
-/**
327
- * __put_user: - Write a simple value into user space, with less checking.
328
- * @x:   Value to copy to user space.
329
- * @ptr: Destination address, in user space.
330
- *
331
- * Context: User context only.  This function may sleep.
332
- *
333
- * This macro copies a single simple value from kernel space to user
334
- * space.  It supports simple types like char and int, but not larger
335
- * data types like structures or arrays.
336
- *
337
- * @ptr must have pointer-to-simple-variable type, and @x must be assignable
338
- * to the result of dereferencing @ptr.
339
- *
340
- * Caller must check the pointer with access_ok() before calling this
341
- * function.
342
- *
343
- * Returns zero on success, or -EFAULT on error.
344
- */
345
-#define __put_user(x, ptr)					\
346
-({								\
347
-	register long __pu_err = 0;				\
348
-	__typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
349
-	__chk_user_ptr(__gu_ptr);				\
277
+#define __put_user_nocheck(x, __gu_ptr, __pu_err)					\
278
+do {								\
350279 	switch (sizeof(*__gu_ptr)) {				\
351280 	case 1:							\
352281 		__put_user_asm("sb", (x), __gu_ptr, __pu_err);	\
....@@ -363,6 +292,41 @@
363292 	default:						\
364293 		BUILD_BUG();					\
365294 	}							\
295
+} while (0)
296
+
297
+/**
298
+ * __put_user: - Write a simple value into user space, with less checking.
299
+ * @x:   Value to copy to user space.
300
+ * @ptr: Destination address, in user space.
301
+ *
302
+ * Context: User context only.  This function may sleep.
303
+ *
304
+ * This macro copies a single simple value from kernel space to user
305
+ * space.  It supports simple types like char and int, but not larger
306
+ * data types like structures or arrays.
307
+ *
308
+ * @ptr must have pointer-to-simple-variable type, and @x must be assignable
309
+ * to the result of dereferencing @ptr. The value of @x is copied to avoid
310
+ * re-ordering where @x is evaluated inside the block that enables user-space
311
+ * access (thus bypassing user space protection if @x is a function).
312
+ *
313
+ * Caller must check the pointer with access_ok() before calling this
314
+ * function.
315
+ *
316
+ * Returns zero on success, or -EFAULT on error.
317
+ */
318
+#define __put_user(x, ptr)					\
319
+({								\
320
+	__typeof__(*(ptr)) __user *__gu_ptr = (ptr);		\
321
+	__typeof__(*__gu_ptr) __val = (x);			\
322
+	long __pu_err = 0;					\
323
+								\
324
+	__chk_user_ptr(__gu_ptr);				\
325
+								\
326
+	__enable_user_access();					\
327
+	__put_user_nocheck(__val, __gu_ptr, __pu_err);		\
328
+	__disable_user_access();				\
329
+								\
366330 	__pu_err;						\
367331 })
368332 
....@@ -386,15 +350,15 @@
386350 ({								\
387351 	__typeof__(*(ptr)) __user *__p = (ptr);			\
388352 	might_fault();						\
389
-	access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ?		\
353
+	access_ok(__p, sizeof(*__p)) ?		\
390354 		__put_user((x), __p) :				\
391355 		-EFAULT;					\
392356 })
393357 
394358 
395
-extern unsigned long __must_check __asm_copy_to_user(void __user *to,
359
+unsigned long __must_check __asm_copy_to_user(void __user *to,
396360 	const void *from, unsigned long n);
397
-extern unsigned long __must_check __asm_copy_from_user(void *to,
361
+unsigned long __must_check __asm_copy_from_user(void *to,
398362 	const void __user *from, unsigned long n);
399363 
400364 static inline unsigned long
....@@ -421,7 +385,7 @@
421385 unsigned long __must_check clear_user(void __user *to, unsigned long n)
422386 {
423387 	might_fault();
424
-	return access_ok(VERIFY_WRITE, to, n) ?
388
+	return access_ok(to, n) ?
425389 		__clear_user(to, n) : n;
426390 }
427391 
....@@ -500,4 +464,27 @@
500464 	__ret;							\
501465 })
502466 
467
+#define HAVE_GET_KERNEL_NOFAULT
468
+
469
+#define __get_kernel_nofault(dst, src, type, err_label)			\
470
+do {									\
471
+	long __kr_err;							\
472
+									\
473
+	__get_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err);	\
474
+	if (unlikely(__kr_err))						\
475
+		goto err_label;						\
476
+} while (0)
477
+
478
+#define __put_kernel_nofault(dst, src, type, err_label)			\
479
+do {									\
480
+	long __kr_err;							\
481
+									\
482
+	__put_user_nocheck(*((type *)(src)), (type *)(dst), __kr_err);	\
483
+	if (unlikely(__kr_err))						\
484
+		goto err_label;						\
485
+} while (0)
486
+
487
+#else /* CONFIG_MMU */
488
+#include <asm-generic/uaccess.h>
489
+#endif /* CONFIG_MMU */
503490 #endif /* _ASM_RISCV_UACCESS_H */