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1965aae3 PA |
1 | #ifndef _ASM_X86_UACCESS_H |
2 | #define _ASM_X86_UACCESS_H | |
ca233862 GC |
3 | /* |
4 | * User space memory access functions | |
5 | */ | |
6 | #include <linux/errno.h> | |
7 | #include <linux/compiler.h> | |
1771c6e1 | 8 | #include <linux/kasan-checks.h> |
ca233862 | 9 | #include <linux/thread_info.h> |
ca233862 GC |
10 | #include <linux/string.h> |
11 | #include <asm/asm.h> | |
12 | #include <asm/page.h> | |
63bcff2a | 13 | #include <asm/smap.h> |
ca233862 GC |
14 | |
15 | #define VERIFY_READ 0 | |
16 | #define VERIFY_WRITE 1 | |
17 | ||
18 | /* | |
19 | * The fs value determines whether argument validity checking should be | |
20 | * performed or not. If get_fs() == USER_DS, checking is performed, with | |
21 | * get_fs() == KERNEL_DS, checking is bypassed. | |
22 | * | |
23 | * For historical reasons, these macros are grossly misnamed. | |
24 | */ | |
25 | ||
26 | #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) | |
27 | ||
28 | #define KERNEL_DS MAKE_MM_SEG(-1UL) | |
9063c61f | 29 | #define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX) |
ca233862 GC |
30 | |
31 | #define get_ds() (KERNEL_DS) | |
13d4ea09 AL |
32 | #define get_fs() (current->thread.addr_limit) |
33 | #define set_fs(x) (current->thread.addr_limit = (x)) | |
ca233862 GC |
34 | |
35 | #define segment_eq(a, b) ((a).seg == (b).seg) | |
36 | ||
13d4ea09 | 37 | #define user_addr_max() (current->thread.addr_limit.seg) |
bc6ca7b3 AS |
38 | #define __addr_ok(addr) \ |
39 | ((unsigned long __force)(addr) < user_addr_max()) | |
002ca169 | 40 | |
ca233862 GC |
41 | /* |
42 | * Test whether a block of memory is a valid user space address. | |
43 | * Returns 0 if the range is valid, nonzero otherwise. | |
ca233862 | 44 | */ |
a740576a | 45 | static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit) |
c5fe5d80 LT |
46 | { |
47 | /* | |
48 | * If we have used "sizeof()" for the size, | |
49 | * we know it won't overflow the limit (but | |
50 | * it might overflow the 'addr', so it's | |
51 | * important to subtract the size from the | |
52 | * limit, not add it to the address). | |
53 | */ | |
54 | if (__builtin_constant_p(size)) | |
7e0f51cb | 55 | return unlikely(addr > limit - size); |
c5fe5d80 LT |
56 | |
57 | /* Arbitrary sizes? Be careful about overflow */ | |
58 | addr += size; | |
7e0f51cb | 59 | if (unlikely(addr < size)) |
a740576a | 60 | return true; |
7e0f51cb | 61 | return unlikely(addr > limit); |
c5fe5d80 | 62 | } |
ca233862 | 63 | |
bc6ca7b3 | 64 | #define __range_not_ok(addr, size, limit) \ |
ca233862 | 65 | ({ \ |
ca233862 | 66 | __chk_user_ptr(addr); \ |
c5fe5d80 | 67 | __chk_range_not_ok((unsigned long __force)(addr), size, limit); \ |
ca233862 GC |
68 | }) |
69 | ||
70 | /** | |
71 | * access_ok: - Checks if a user space pointer is valid | |
72 | * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that | |
73 | * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe | |
74 | * to write to a block, it is always safe to read from it. | |
75 | * @addr: User space pointer to start of block to check | |
76 | * @size: Size of block to check | |
77 | * | |
b3c395ef DH |
78 | * Context: User context only. This function may sleep if pagefaults are |
79 | * enabled. | |
ca233862 GC |
80 | * |
81 | * Checks if a pointer to a block of memory in user space is valid. | |
82 | * | |
83 | * Returns true (nonzero) if the memory block may be valid, false (zero) | |
84 | * if it is definitely invalid. | |
85 | * | |
86 | * Note that, depending on architecture, this function probably just | |
87 | * checks that the pointer is in the user space range - after calling | |
88 | * this function, memory access functions may still return -EFAULT. | |
89 | */ | |
bc6ca7b3 | 90 | #define access_ok(type, addr, size) \ |
a740576a | 91 | likely(!__range_not_ok(addr, size, user_addr_max())) |
ca233862 GC |
92 | |
93 | /* | |
548acf19 TL |
94 | * The exception table consists of triples of addresses relative to the |
95 | * exception table entry itself. The first address is of an instruction | |
96 | * that is allowed to fault, the second is the target at which the program | |
97 | * should continue. The third is a handler function to deal with the fault | |
98 | * caused by the instruction in the first field. | |
ca233862 GC |
99 | * |
100 | * All the routines below use bits of fixup code that are out of line | |
101 | * with the main instruction path. This means when everything is well, | |
102 | * we don't even have to jump over them. Further, they do not intrude | |
103 | * on our cache or tlb entries. | |
104 | */ | |
105 | ||
106 | struct exception_table_entry { | |
548acf19 | 107 | int insn, fixup, handler; |
ca233862 | 108 | }; |
29934b0f AB |
109 | |
110 | #define ARCH_HAS_RELATIVE_EXTABLE | |
ca233862 | 111 | |
67d7a982 MK |
112 | #define swap_ex_entry_fixup(a, b, tmp, delta) \ |
113 | do { \ | |
114 | (a)->fixup = (b)->fixup + (delta); \ | |
115 | (b)->fixup = (tmp).fixup - (delta); \ | |
116 | (a)->handler = (b)->handler + (delta); \ | |
117 | (b)->handler = (tmp).handler - (delta); \ | |
118 | } while (0) | |
119 | ||
548acf19 TL |
120 | extern int fixup_exception(struct pt_regs *regs, int trapnr); |
121 | extern bool ex_has_fault_handler(unsigned long ip); | |
0e861fbb | 122 | extern void early_fixup_exception(struct pt_regs *regs, int trapnr); |
ca233862 GC |
123 | |
124 | /* | |
125 | * These are the main single-value transfer routines. They automatically | |
126 | * use the right size if we just have the right pointer type. | |
127 | * | |
128 | * This gets kind of ugly. We want to return _two_ values in "get_user()" | |
129 | * and yet we don't want to do any pointers, because that is too much | |
130 | * of a performance impact. Thus we have a few rather ugly macros here, | |
131 | * and hide all the ugliness from the user. | |
132 | * | |
133 | * The "__xxx" versions of the user access functions are versions that | |
134 | * do not verify the address space, that must have been done previously | |
135 | * with a separate "access_ok()" call (this is used when we do multiple | |
136 | * accesses to the same area of user memory). | |
137 | */ | |
138 | ||
139 | extern int __get_user_1(void); | |
140 | extern int __get_user_2(void); | |
141 | extern int __get_user_4(void); | |
142 | extern int __get_user_8(void); | |
143 | extern int __get_user_bad(void); | |
144 | ||
11f1a4b9 LT |
145 | #define __uaccess_begin() stac() |
146 | #define __uaccess_end() clac() | |
147 | ||
3578baae PA |
148 | /* |
149 | * This is a type: either unsigned long, if the argument fits into | |
150 | * that type, or otherwise unsigned long long. | |
151 | */ | |
152 | #define __inttype(x) \ | |
153 | __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) | |
865e5b76 GC |
154 | |
155 | /** | |
156 | * get_user: - Get a simple variable from user space. | |
157 | * @x: Variable to store result. | |
158 | * @ptr: Source address, in user space. | |
159 | * | |
b3c395ef DH |
160 | * Context: User context only. This function may sleep if pagefaults are |
161 | * enabled. | |
865e5b76 GC |
162 | * |
163 | * This macro copies a single simple variable from user space to kernel | |
164 | * space. It supports simple types like char and int, but not larger | |
165 | * data types like structures or arrays. | |
166 | * | |
167 | * @ptr must have pointer-to-simple-variable type, and the result of | |
168 | * dereferencing @ptr must be assignable to @x without a cast. | |
169 | * | |
170 | * Returns zero on success, or -EFAULT on error. | |
171 | * On error, the variable @x is set to zero. | |
ff52c3b0 PA |
172 | */ |
173 | /* | |
3578baae PA |
174 | * Careful: we have to cast the result to the type of the pointer |
175 | * for sign reasons. | |
ff52c3b0 | 176 | * |
f69fa9a9 | 177 | * The use of _ASM_DX as the register specifier is a bit of a |
ff52c3b0 PA |
178 | * simplification, as gcc only cares about it as the starting point |
179 | * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits | |
180 | * (%ecx being the next register in gcc's x86 register sequence), and | |
181 | * %rdx on 64 bits. | |
f69fa9a9 PA |
182 | * |
183 | * Clang/LLVM cares about the size of the register, but still wants | |
184 | * the base register for something that ends up being a pair. | |
865e5b76 | 185 | */ |
865e5b76 GC |
186 | #define get_user(x, ptr) \ |
187 | ({ \ | |
188 | int __ret_gu; \ | |
bdfc017e | 189 | register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \ |
f05058c4 | 190 | register void *__sp asm(_ASM_SP); \ |
865e5b76 | 191 | __chk_user_ptr(ptr); \ |
3ee1afa3 | 192 | might_fault(); \ |
f05058c4 CA |
193 | asm volatile("call __get_user_%P4" \ |
194 | : "=a" (__ret_gu), "=r" (__val_gu), "+r" (__sp) \ | |
3578baae | 195 | : "0" (ptr), "i" (sizeof(*(ptr)))); \ |
e182c570 | 196 | (x) = (__force __typeof__(*(ptr))) __val_gu; \ |
a76cf66e | 197 | __builtin_expect(__ret_gu, 0); \ |
865e5b76 GC |
198 | }) |
199 | ||
e30a44fd GC |
200 | #define __put_user_x(size, x, ptr, __ret_pu) \ |
201 | asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ | |
4d5d7838 | 202 | : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") |
e30a44fd GC |
203 | |
204 | ||
205 | ||
dc70ddf4 | 206 | #ifdef CONFIG_X86_32 |
18114f61 | 207 | #define __put_user_asm_u64(x, addr, err, errret) \ |
11f1a4b9 | 208 | asm volatile("\n" \ |
63bcff2a | 209 | "1: movl %%eax,0(%2)\n" \ |
dc70ddf4 | 210 | "2: movl %%edx,4(%2)\n" \ |
11f1a4b9 | 211 | "3:" \ |
dc70ddf4 GC |
212 | ".section .fixup,\"ax\"\n" \ |
213 | "4: movl %3,%0\n" \ | |
214 | " jmp 3b\n" \ | |
215 | ".previous\n" \ | |
216 | _ASM_EXTABLE(1b, 4b) \ | |
217 | _ASM_EXTABLE(2b, 4b) \ | |
218 | : "=r" (err) \ | |
18114f61 | 219 | : "A" (x), "r" (addr), "i" (errret), "0" (err)) |
e30a44fd | 220 | |
fe40c0af | 221 | #define __put_user_asm_ex_u64(x, addr) \ |
11f1a4b9 | 222 | asm volatile("\n" \ |
63bcff2a | 223 | "1: movl %%eax,0(%1)\n" \ |
fe40c0af | 224 | "2: movl %%edx,4(%1)\n" \ |
11f1a4b9 | 225 | "3:" \ |
535c0c34 PA |
226 | _ASM_EXTABLE_EX(1b, 2b) \ |
227 | _ASM_EXTABLE_EX(2b, 3b) \ | |
fe40c0af HS |
228 | : : "A" (x), "r" (addr)) |
229 | ||
e30a44fd GC |
230 | #define __put_user_x8(x, ptr, __ret_pu) \ |
231 | asm volatile("call __put_user_8" : "=a" (__ret_pu) \ | |
232 | : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") | |
dc70ddf4 | 233 | #else |
18114f61 | 234 | #define __put_user_asm_u64(x, ptr, retval, errret) \ |
ebe119cd | 235 | __put_user_asm(x, ptr, retval, "q", "", "er", errret) |
fe40c0af | 236 | #define __put_user_asm_ex_u64(x, addr) \ |
ebe119cd | 237 | __put_user_asm_ex(x, addr, "q", "", "er") |
e30a44fd | 238 | #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu) |
dc70ddf4 GC |
239 | #endif |
240 | ||
e30a44fd GC |
241 | extern void __put_user_bad(void); |
242 | ||
243 | /* | |
244 | * Strange magic calling convention: pointer in %ecx, | |
245 | * value in %eax(:%edx), return value in %eax. clobbers %rbx | |
246 | */ | |
247 | extern void __put_user_1(void); | |
248 | extern void __put_user_2(void); | |
249 | extern void __put_user_4(void); | |
250 | extern void __put_user_8(void); | |
251 | ||
e30a44fd GC |
252 | /** |
253 | * put_user: - Write a simple value into user space. | |
254 | * @x: Value to copy to user space. | |
255 | * @ptr: Destination address, in user space. | |
256 | * | |
b3c395ef DH |
257 | * Context: User context only. This function may sleep if pagefaults are |
258 | * enabled. | |
e30a44fd GC |
259 | * |
260 | * This macro copies a single simple value from kernel space to user | |
261 | * space. It supports simple types like char and int, but not larger | |
262 | * data types like structures or arrays. | |
263 | * | |
264 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable | |
265 | * to the result of dereferencing @ptr. | |
266 | * | |
267 | * Returns zero on success, or -EFAULT on error. | |
268 | */ | |
269 | #define put_user(x, ptr) \ | |
270 | ({ \ | |
271 | int __ret_pu; \ | |
272 | __typeof__(*(ptr)) __pu_val; \ | |
273 | __chk_user_ptr(ptr); \ | |
3ee1afa3 | 274 | might_fault(); \ |
e30a44fd GC |
275 | __pu_val = x; \ |
276 | switch (sizeof(*(ptr))) { \ | |
277 | case 1: \ | |
278 | __put_user_x(1, __pu_val, ptr, __ret_pu); \ | |
279 | break; \ | |
280 | case 2: \ | |
281 | __put_user_x(2, __pu_val, ptr, __ret_pu); \ | |
282 | break; \ | |
283 | case 4: \ | |
284 | __put_user_x(4, __pu_val, ptr, __ret_pu); \ | |
285 | break; \ | |
286 | case 8: \ | |
287 | __put_user_x8(__pu_val, ptr, __ret_pu); \ | |
288 | break; \ | |
289 | default: \ | |
290 | __put_user_x(X, __pu_val, ptr, __ret_pu); \ | |
291 | break; \ | |
292 | } \ | |
a76cf66e | 293 | __builtin_expect(__ret_pu, 0); \ |
e30a44fd GC |
294 | }) |
295 | ||
dc70ddf4 GC |
296 | #define __put_user_size(x, ptr, size, retval, errret) \ |
297 | do { \ | |
298 | retval = 0; \ | |
299 | __chk_user_ptr(ptr); \ | |
300 | switch (size) { \ | |
301 | case 1: \ | |
302 | __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \ | |
303 | break; \ | |
304 | case 2: \ | |
305 | __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \ | |
306 | break; \ | |
307 | case 4: \ | |
4d5d7838 | 308 | __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \ |
dc70ddf4 GC |
309 | break; \ |
310 | case 8: \ | |
18114f61 HS |
311 | __put_user_asm_u64((__typeof__(*ptr))(x), ptr, retval, \ |
312 | errret); \ | |
dc70ddf4 GC |
313 | break; \ |
314 | default: \ | |
315 | __put_user_bad(); \ | |
316 | } \ | |
317 | } while (0) | |
318 | ||
11f1a4b9 LT |
319 | /* |
320 | * This doesn't do __uaccess_begin/end - the exception handling | |
321 | * around it must do that. | |
322 | */ | |
fe40c0af HS |
323 | #define __put_user_size_ex(x, ptr, size) \ |
324 | do { \ | |
325 | __chk_user_ptr(ptr); \ | |
326 | switch (size) { \ | |
327 | case 1: \ | |
328 | __put_user_asm_ex(x, ptr, "b", "b", "iq"); \ | |
329 | break; \ | |
330 | case 2: \ | |
331 | __put_user_asm_ex(x, ptr, "w", "w", "ir"); \ | |
332 | break; \ | |
333 | case 4: \ | |
334 | __put_user_asm_ex(x, ptr, "l", "k", "ir"); \ | |
335 | break; \ | |
336 | case 8: \ | |
337 | __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr); \ | |
338 | break; \ | |
339 | default: \ | |
340 | __put_user_bad(); \ | |
341 | } \ | |
342 | } while (0) | |
343 | ||
3f168221 | 344 | #ifdef CONFIG_X86_32 |
b2f68038 BL |
345 | #define __get_user_asm_u64(x, ptr, retval, errret) \ |
346 | ({ \ | |
347 | __typeof__(ptr) __ptr = (ptr); \ | |
348 | asm volatile(ASM_STAC "\n" \ | |
349 | "1: movl %2,%%eax\n" \ | |
350 | "2: movl %3,%%edx\n" \ | |
351 | "3: " ASM_CLAC "\n" \ | |
352 | ".section .fixup,\"ax\"\n" \ | |
353 | "4: mov %4,%0\n" \ | |
354 | " xorl %%eax,%%eax\n" \ | |
355 | " xorl %%edx,%%edx\n" \ | |
356 | " jmp 3b\n" \ | |
357 | ".previous\n" \ | |
358 | _ASM_EXTABLE(1b, 4b) \ | |
359 | _ASM_EXTABLE(2b, 4b) \ | |
360 | : "=r" (retval), "=A"(x) \ | |
361 | : "m" (__m(__ptr)), "m" __m(((u32 *)(__ptr)) + 1), \ | |
362 | "i" (errret), "0" (retval)); \ | |
363 | }) | |
364 | ||
fe40c0af | 365 | #define __get_user_asm_ex_u64(x, ptr) (x) = __get_user_bad() |
3f168221 GC |
366 | #else |
367 | #define __get_user_asm_u64(x, ptr, retval, errret) \ | |
368 | __get_user_asm(x, ptr, retval, "q", "", "=r", errret) | |
fe40c0af HS |
369 | #define __get_user_asm_ex_u64(x, ptr) \ |
370 | __get_user_asm_ex(x, ptr, "q", "", "=r") | |
3f168221 GC |
371 | #endif |
372 | ||
373 | #define __get_user_size(x, ptr, size, retval, errret) \ | |
374 | do { \ | |
375 | retval = 0; \ | |
376 | __chk_user_ptr(ptr); \ | |
377 | switch (size) { \ | |
378 | case 1: \ | |
379 | __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \ | |
380 | break; \ | |
381 | case 2: \ | |
382 | __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \ | |
383 | break; \ | |
384 | case 4: \ | |
385 | __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \ | |
386 | break; \ | |
387 | case 8: \ | |
388 | __get_user_asm_u64(x, ptr, retval, errret); \ | |
389 | break; \ | |
390 | default: \ | |
391 | (x) = __get_user_bad(); \ | |
392 | } \ | |
393 | } while (0) | |
394 | ||
395 | #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ | |
11f1a4b9 | 396 | asm volatile("\n" \ |
63bcff2a | 397 | "1: mov"itype" %2,%"rtype"1\n" \ |
11f1a4b9 | 398 | "2:\n" \ |
3f168221 GC |
399 | ".section .fixup,\"ax\"\n" \ |
400 | "3: mov %3,%0\n" \ | |
401 | " xor"itype" %"rtype"1,%"rtype"1\n" \ | |
402 | " jmp 2b\n" \ | |
403 | ".previous\n" \ | |
404 | _ASM_EXTABLE(1b, 3b) \ | |
405 | : "=r" (err), ltype(x) \ | |
406 | : "m" (__m(addr)), "i" (errret), "0" (err)) | |
407 | ||
11f1a4b9 LT |
408 | /* |
409 | * This doesn't do __uaccess_begin/end - the exception handling | |
410 | * around it must do that. | |
411 | */ | |
fe40c0af HS |
412 | #define __get_user_size_ex(x, ptr, size) \ |
413 | do { \ | |
414 | __chk_user_ptr(ptr); \ | |
415 | switch (size) { \ | |
416 | case 1: \ | |
417 | __get_user_asm_ex(x, ptr, "b", "b", "=q"); \ | |
418 | break; \ | |
419 | case 2: \ | |
420 | __get_user_asm_ex(x, ptr, "w", "w", "=r"); \ | |
421 | break; \ | |
422 | case 4: \ | |
423 | __get_user_asm_ex(x, ptr, "l", "k", "=r"); \ | |
424 | break; \ | |
425 | case 8: \ | |
426 | __get_user_asm_ex_u64(x, ptr); \ | |
427 | break; \ | |
428 | default: \ | |
429 | (x) = __get_user_bad(); \ | |
430 | } \ | |
431 | } while (0) | |
432 | ||
433 | #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \ | |
5e88353d PA |
434 | asm volatile("1: mov"itype" %1,%"rtype"0\n" \ |
435 | "2:\n" \ | |
535c0c34 | 436 | _ASM_EXTABLE_EX(1b, 2b) \ |
fe40c0af HS |
437 | : ltype(x) : "m" (__m(addr))) |
438 | ||
dc70ddf4 GC |
439 | #define __put_user_nocheck(x, ptr, size) \ |
440 | ({ \ | |
16855f87 | 441 | int __pu_err; \ |
11f1a4b9 | 442 | __uaccess_begin(); \ |
dc70ddf4 | 443 | __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ |
11f1a4b9 | 444 | __uaccess_end(); \ |
a76cf66e | 445 | __builtin_expect(__pu_err, 0); \ |
dc70ddf4 GC |
446 | }) |
447 | ||
3f168221 GC |
448 | #define __get_user_nocheck(x, ptr, size) \ |
449 | ({ \ | |
16855f87 | 450 | int __gu_err; \ |
b2f68038 | 451 | __inttype(*(ptr)) __gu_val; \ |
11f1a4b9 | 452 | __uaccess_begin(); \ |
3f168221 | 453 | __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ |
11f1a4b9 | 454 | __uaccess_end(); \ |
3f168221 | 455 | (x) = (__force __typeof__(*(ptr)))__gu_val; \ |
a76cf66e | 456 | __builtin_expect(__gu_err, 0); \ |
3f168221 | 457 | }) |
dc70ddf4 GC |
458 | |
459 | /* FIXME: this hack is definitely wrong -AK */ | |
460 | struct __large_struct { unsigned long buf[100]; }; | |
461 | #define __m(x) (*(struct __large_struct __user *)(x)) | |
462 | ||
463 | /* | |
464 | * Tell gcc we read from memory instead of writing: this is because | |
465 | * we do not write to any memory gcc knows about, so there are no | |
466 | * aliasing issues. | |
467 | */ | |
468 | #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ | |
11f1a4b9 | 469 | asm volatile("\n" \ |
63bcff2a | 470 | "1: mov"itype" %"rtype"1,%2\n" \ |
11f1a4b9 | 471 | "2:\n" \ |
dc70ddf4 GC |
472 | ".section .fixup,\"ax\"\n" \ |
473 | "3: mov %3,%0\n" \ | |
474 | " jmp 2b\n" \ | |
475 | ".previous\n" \ | |
476 | _ASM_EXTABLE(1b, 3b) \ | |
477 | : "=r"(err) \ | |
478 | : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) | |
fe40c0af HS |
479 | |
480 | #define __put_user_asm_ex(x, addr, itype, rtype, ltype) \ | |
5e88353d PA |
481 | asm volatile("1: mov"itype" %"rtype"0,%1\n" \ |
482 | "2:\n" \ | |
535c0c34 | 483 | _ASM_EXTABLE_EX(1b, 2b) \ |
fe40c0af HS |
484 | : : ltype(x), "m" (__m(addr))) |
485 | ||
486 | /* | |
487 | * uaccess_try and catch | |
488 | */ | |
489 | #define uaccess_try do { \ | |
dfa9a942 | 490 | current->thread.uaccess_err = 0; \ |
11f1a4b9 | 491 | __uaccess_begin(); \ |
fe40c0af HS |
492 | barrier(); |
493 | ||
494 | #define uaccess_catch(err) \ | |
11f1a4b9 | 495 | __uaccess_end(); \ |
dfa9a942 | 496 | (err) |= (current->thread.uaccess_err ? -EFAULT : 0); \ |
fe40c0af HS |
497 | } while (0) |
498 | ||
8cb834e9 GC |
499 | /** |
500 | * __get_user: - Get a simple variable from user space, with less checking. | |
501 | * @x: Variable to store result. | |
502 | * @ptr: Source address, in user space. | |
503 | * | |
b3c395ef DH |
504 | * Context: User context only. This function may sleep if pagefaults are |
505 | * enabled. | |
8cb834e9 GC |
506 | * |
507 | * This macro copies a single simple variable from user space to kernel | |
508 | * space. It supports simple types like char and int, but not larger | |
509 | * data types like structures or arrays. | |
510 | * | |
511 | * @ptr must have pointer-to-simple-variable type, and the result of | |
512 | * dereferencing @ptr must be assignable to @x without a cast. | |
513 | * | |
514 | * Caller must check the pointer with access_ok() before calling this | |
515 | * function. | |
516 | * | |
517 | * Returns zero on success, or -EFAULT on error. | |
518 | * On error, the variable @x is set to zero. | |
519 | */ | |
520 | ||
521 | #define __get_user(x, ptr) \ | |
522 | __get_user_nocheck((x), (ptr), sizeof(*(ptr))) | |
fe40c0af | 523 | |
8cb834e9 GC |
524 | /** |
525 | * __put_user: - Write a simple value into user space, with less checking. | |
526 | * @x: Value to copy to user space. | |
527 | * @ptr: Destination address, in user space. | |
528 | * | |
b3c395ef DH |
529 | * Context: User context only. This function may sleep if pagefaults are |
530 | * enabled. | |
8cb834e9 GC |
531 | * |
532 | * This macro copies a single simple value from kernel space to user | |
533 | * space. It supports simple types like char and int, but not larger | |
534 | * data types like structures or arrays. | |
535 | * | |
536 | * @ptr must have pointer-to-simple-variable type, and @x must be assignable | |
537 | * to the result of dereferencing @ptr. | |
538 | * | |
539 | * Caller must check the pointer with access_ok() before calling this | |
540 | * function. | |
541 | * | |
542 | * Returns zero on success, or -EFAULT on error. | |
543 | */ | |
544 | ||
545 | #define __put_user(x, ptr) \ | |
546 | __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) | |
dc70ddf4 | 547 | |
8cb834e9 GC |
548 | #define __get_user_unaligned __get_user |
549 | #define __put_user_unaligned __put_user | |
865e5b76 | 550 | |
fe40c0af HS |
551 | /* |
552 | * {get|put}_user_try and catch | |
553 | * | |
554 | * get_user_try { | |
555 | * get_user_ex(...); | |
556 | * } get_user_catch(err) | |
557 | */ | |
558 | #define get_user_try uaccess_try | |
559 | #define get_user_catch(err) uaccess_catch(err) | |
fe40c0af HS |
560 | |
561 | #define get_user_ex(x, ptr) do { \ | |
562 | unsigned long __gue_val; \ | |
563 | __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr)))); \ | |
564 | (x) = (__force __typeof__(*(ptr)))__gue_val; \ | |
565 | } while (0) | |
566 | ||
019a1369 HS |
567 | #define put_user_try uaccess_try |
568 | #define put_user_catch(err) uaccess_catch(err) | |
569 | ||
fe40c0af HS |
570 | #define put_user_ex(x, ptr) \ |
571 | __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) | |
572 | ||
1ac2e6ca RR |
573 | extern unsigned long |
574 | copy_from_user_nmi(void *to, const void __user *from, unsigned long n); | |
92ae03f2 LT |
575 | extern __must_check long |
576 | strncpy_from_user(char *dst, const char __user *src, long count); | |
1ac2e6ca | 577 | |
5723aa99 LT |
578 | extern __must_check long strlen_user(const char __user *str); |
579 | extern __must_check long strnlen_user(const char __user *str, long n); | |
580 | ||
a052858f PA |
581 | unsigned long __must_check clear_user(void __user *mem, unsigned long len); |
582 | unsigned long __must_check __clear_user(void __user *mem, unsigned long len); | |
583 | ||
f09174c5 QR |
584 | extern void __cmpxchg_wrong_size(void) |
585 | __compiletime_error("Bad argument size for cmpxchg"); | |
586 | ||
587 | #define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size) \ | |
588 | ({ \ | |
589 | int __ret = 0; \ | |
590 | __typeof__(ptr) __uval = (uval); \ | |
591 | __typeof__(*(ptr)) __old = (old); \ | |
592 | __typeof__(*(ptr)) __new = (new); \ | |
11f1a4b9 | 593 | __uaccess_begin(); \ |
f09174c5 QR |
594 | switch (size) { \ |
595 | case 1: \ | |
596 | { \ | |
11f1a4b9 | 597 | asm volatile("\n" \ |
f09174c5 | 598 | "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n" \ |
11f1a4b9 | 599 | "2:\n" \ |
f09174c5 QR |
600 | "\t.section .fixup, \"ax\"\n" \ |
601 | "3:\tmov %3, %0\n" \ | |
602 | "\tjmp 2b\n" \ | |
603 | "\t.previous\n" \ | |
604 | _ASM_EXTABLE(1b, 3b) \ | |
605 | : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ | |
606 | : "i" (-EFAULT), "q" (__new), "1" (__old) \ | |
607 | : "memory" \ | |
608 | ); \ | |
609 | break; \ | |
610 | } \ | |
611 | case 2: \ | |
612 | { \ | |
11f1a4b9 | 613 | asm volatile("\n" \ |
f09174c5 | 614 | "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n" \ |
11f1a4b9 | 615 | "2:\n" \ |
f09174c5 QR |
616 | "\t.section .fixup, \"ax\"\n" \ |
617 | "3:\tmov %3, %0\n" \ | |
618 | "\tjmp 2b\n" \ | |
619 | "\t.previous\n" \ | |
620 | _ASM_EXTABLE(1b, 3b) \ | |
621 | : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ | |
622 | : "i" (-EFAULT), "r" (__new), "1" (__old) \ | |
623 | : "memory" \ | |
624 | ); \ | |
625 | break; \ | |
626 | } \ | |
627 | case 4: \ | |
628 | { \ | |
11f1a4b9 | 629 | asm volatile("\n" \ |
f09174c5 | 630 | "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n" \ |
11f1a4b9 | 631 | "2:\n" \ |
f09174c5 QR |
632 | "\t.section .fixup, \"ax\"\n" \ |
633 | "3:\tmov %3, %0\n" \ | |
634 | "\tjmp 2b\n" \ | |
635 | "\t.previous\n" \ | |
636 | _ASM_EXTABLE(1b, 3b) \ | |
637 | : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ | |
638 | : "i" (-EFAULT), "r" (__new), "1" (__old) \ | |
639 | : "memory" \ | |
640 | ); \ | |
641 | break; \ | |
642 | } \ | |
643 | case 8: \ | |
644 | { \ | |
645 | if (!IS_ENABLED(CONFIG_X86_64)) \ | |
646 | __cmpxchg_wrong_size(); \ | |
647 | \ | |
11f1a4b9 | 648 | asm volatile("\n" \ |
f09174c5 | 649 | "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n" \ |
11f1a4b9 | 650 | "2:\n" \ |
f09174c5 QR |
651 | "\t.section .fixup, \"ax\"\n" \ |
652 | "3:\tmov %3, %0\n" \ | |
653 | "\tjmp 2b\n" \ | |
654 | "\t.previous\n" \ | |
655 | _ASM_EXTABLE(1b, 3b) \ | |
656 | : "+r" (__ret), "=a" (__old), "+m" (*(ptr)) \ | |
657 | : "i" (-EFAULT), "r" (__new), "1" (__old) \ | |
658 | : "memory" \ | |
659 | ); \ | |
660 | break; \ | |
661 | } \ | |
662 | default: \ | |
663 | __cmpxchg_wrong_size(); \ | |
664 | } \ | |
11f1a4b9 | 665 | __uaccess_end(); \ |
f09174c5 QR |
666 | *__uval = __old; \ |
667 | __ret; \ | |
668 | }) | |
669 | ||
670 | #define user_atomic_cmpxchg_inatomic(uval, ptr, old, new) \ | |
671 | ({ \ | |
672 | access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \ | |
673 | __user_atomic_cmpxchg_inatomic((uval), (ptr), \ | |
674 | (old), (new), sizeof(*(ptr))) : \ | |
675 | -EFAULT; \ | |
676 | }) | |
677 | ||
8bc7de0c GC |
678 | /* |
679 | * movsl can be slow when source and dest are not both 8-byte aligned | |
680 | */ | |
681 | #ifdef CONFIG_X86_INTEL_USERCOPY | |
682 | extern struct movsl_mask { | |
683 | int mask; | |
684 | } ____cacheline_aligned_in_smp movsl_mask; | |
685 | #endif | |
686 | ||
22cac167 GC |
687 | #define ARCH_HAS_NOCACHE_UACCESS 1 |
688 | ||
96a388de | 689 | #ifdef CONFIG_X86_32 |
a1ce3928 | 690 | # include <asm/uaccess_32.h> |
96a388de | 691 | #else |
a1ce3928 | 692 | # include <asm/uaccess_64.h> |
96a388de | 693 | #endif |
ca233862 | 694 | |
3df7b41a JB |
695 | unsigned long __must_check _copy_from_user(void *to, const void __user *from, |
696 | unsigned n); | |
7a3d9b0f JB |
697 | unsigned long __must_check _copy_to_user(void __user *to, const void *from, |
698 | unsigned n); | |
3df7b41a JB |
699 | |
700 | #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS | |
701 | # define copy_user_diag __compiletime_error | |
702 | #else | |
703 | # define copy_user_diag __compiletime_warning | |
704 | #endif | |
705 | ||
706 | extern void copy_user_diag("copy_from_user() buffer size is too small") | |
707 | copy_from_user_overflow(void); | |
7a3d9b0f JB |
708 | extern void copy_user_diag("copy_to_user() buffer size is too small") |
709 | copy_to_user_overflow(void) __asm__("copy_from_user_overflow"); | |
3df7b41a JB |
710 | |
711 | #undef copy_user_diag | |
712 | ||
713 | #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS | |
714 | ||
715 | extern void | |
716 | __compiletime_warning("copy_from_user() buffer size is not provably correct") | |
717 | __copy_from_user_overflow(void) __asm__("copy_from_user_overflow"); | |
718 | #define __copy_from_user_overflow(size, count) __copy_from_user_overflow() | |
719 | ||
7a3d9b0f JB |
720 | extern void |
721 | __compiletime_warning("copy_to_user() buffer size is not provably correct") | |
722 | __copy_to_user_overflow(void) __asm__("copy_from_user_overflow"); | |
723 | #define __copy_to_user_overflow(size, count) __copy_to_user_overflow() | |
724 | ||
3df7b41a JB |
725 | #else |
726 | ||
727 | static inline void | |
728 | __copy_from_user_overflow(int size, unsigned long count) | |
729 | { | |
730 | WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count); | |
731 | } | |
732 | ||
7a3d9b0f JB |
733 | #define __copy_to_user_overflow __copy_from_user_overflow |
734 | ||
3df7b41a JB |
735 | #endif |
736 | ||
737 | static inline unsigned long __must_check | |
738 | copy_from_user(void *to, const void __user *from, unsigned long n) | |
739 | { | |
740 | int sz = __compiletime_object_size(to); | |
741 | ||
742 | might_fault(); | |
743 | ||
1771c6e1 AR |
744 | kasan_check_write(to, n); |
745 | ||
3df7b41a JB |
746 | /* |
747 | * While we would like to have the compiler do the checking for us | |
748 | * even in the non-constant size case, any false positives there are | |
749 | * a problem (especially when DEBUG_STRICT_USER_COPY_CHECKS, but even | |
750 | * without - the [hopefully] dangerous looking nature of the warning | |
751 | * would make people go look at the respecitive call sites over and | |
752 | * over again just to find that there's no problem). | |
753 | * | |
754 | * And there are cases where it's just not realistic for the compiler | |
755 | * to prove the count to be in range. For example when multiple call | |
756 | * sites of a helper function - perhaps in different source files - | |
757 | * all doing proper range checking, yet the helper function not doing | |
758 | * so again. | |
759 | * | |
760 | * Therefore limit the compile time checking to the constant size | |
761 | * case, and do only runtime checking for non-constant sizes. | |
762 | */ | |
763 | ||
764 | if (likely(sz < 0 || sz >= n)) | |
765 | n = _copy_from_user(to, from, n); | |
766 | else if(__builtin_constant_p(n)) | |
767 | copy_from_user_overflow(); | |
768 | else | |
769 | __copy_from_user_overflow(sz, n); | |
770 | ||
771 | return n; | |
772 | } | |
773 | ||
7a3d9b0f JB |
774 | static inline unsigned long __must_check |
775 | copy_to_user(void __user *to, const void *from, unsigned long n) | |
776 | { | |
777 | int sz = __compiletime_object_size(from); | |
778 | ||
1771c6e1 AR |
779 | kasan_check_read(from, n); |
780 | ||
7a3d9b0f JB |
781 | might_fault(); |
782 | ||
783 | /* See the comment in copy_from_user() above. */ | |
784 | if (likely(sz < 0 || sz >= n)) | |
785 | n = _copy_to_user(to, from, n); | |
786 | else if(__builtin_constant_p(n)) | |
787 | copy_to_user_overflow(); | |
788 | else | |
789 | __copy_to_user_overflow(sz, n); | |
790 | ||
791 | return n; | |
792 | } | |
793 | ||
3df7b41a | 794 | #undef __copy_from_user_overflow |
7a3d9b0f | 795 | #undef __copy_to_user_overflow |
3df7b41a | 796 | |
10013ebb AK |
797 | /* |
798 | * We rely on the nested NMI work to allow atomic faults from the NMI path; the | |
799 | * nested NMI paths are careful to preserve CR2. | |
800 | * | |
801 | * Caller must use pagefault_enable/disable, or run in interrupt context, | |
802 | * and also do a uaccess_ok() check | |
803 | */ | |
804 | #define __copy_from_user_nmi __copy_from_user_inatomic | |
805 | ||
5b24a7a2 LT |
806 | /* |
807 | * The "unsafe" user accesses aren't really "unsafe", but the naming | |
808 | * is a big fat warning: you have to not only do the access_ok() | |
809 | * checking before using them, but you have to surround them with the | |
810 | * user_access_begin/end() pair. | |
811 | */ | |
812 | #define user_access_begin() __uaccess_begin() | |
813 | #define user_access_end() __uaccess_end() | |
814 | ||
815 | #define unsafe_put_user(x, ptr) \ | |
816 | ({ \ | |
817 | int __pu_err; \ | |
818 | __put_user_size((x), (ptr), sizeof(*(ptr)), __pu_err, -EFAULT); \ | |
819 | __builtin_expect(__pu_err, 0); \ | |
820 | }) | |
821 | ||
822 | #define unsafe_get_user(x, ptr) \ | |
823 | ({ \ | |
824 | int __gu_err; \ | |
825 | unsigned long __gu_val; \ | |
826 | __get_user_size(__gu_val, (ptr), sizeof(*(ptr)), __gu_err, -EFAULT); \ | |
827 | (x) = (__force __typeof__(*(ptr)))__gu_val; \ | |
828 | __builtin_expect(__gu_err, 0); \ | |
829 | }) | |
830 | ||
1965aae3 | 831 | #endif /* _ASM_X86_UACCESS_H */ |
8174c430 | 832 |