2 * arch/arm/include/asm/uaccess.h
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 #ifndef _ASMARM_UACCESS_H
9 #define _ASMARM_UACCESS_H
12 * User space memory access functions
14 #include <linux/string.h>
15 #include <linux/thread_info.h>
16 #include <asm/errno.h>
17 #include <asm/memory.h>
18 #include <asm/domain.h>
19 #include <asm/unified.h>
20 #include <asm/compiler.h>
22 #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
23 #include <asm-generic/uaccess-unaligned.h>
25 #define __get_user_unaligned __get_user
26 #define __put_user_unaligned __put_user
30 #define VERIFY_WRITE 1
33 * The exception table consists of pairs of addresses: the first is the
34 * address of an instruction that is allowed to fault, and the second is
35 * the address at which the program should continue. No registers are
36 * modified, so it is entirely up to the continuation code to figure out
39 * All the routines below use bits of fixup code that are out of line
40 * with the main instruction path. This means when everything is well,
41 * we don't even have to jump over them. Further, they do not intrude
42 * on our cache or tlb entries.
45 struct exception_table_entry
47 unsigned long insn, fixup;
50 extern int fixup_exception(struct pt_regs *regs);
53 * These two functions allow hooking accesses to userspace to increase
54 * system integrity by ensuring that the kernel can not inadvertantly
55 * perform such accesses (eg, via list poison values) which could then
56 * be exploited for priviledge escalation.
58 static inline unsigned int uaccess_save_and_enable(void)
60 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
61 unsigned int old_domain = get_domain();
63 /* Set the current domain access to permit user accesses */
64 set_domain((old_domain & ~domain_mask(DOMAIN_USER)) |
65 domain_val(DOMAIN_USER, DOMAIN_CLIENT));
73 static inline void uaccess_restore(unsigned int flags)
75 #ifdef CONFIG_CPU_SW_DOMAIN_PAN
76 /* Restore the user access mask */
82 * These two are intentionally not defined anywhere - if the kernel
83 * code generates any references to them, that's a bug.
85 extern int __get_user_bad(void);
86 extern int __put_user_bad(void);
89 * Note that this is actually 0x1,0000,0000
91 #define KERNEL_DS 0x00000000
92 #define get_ds() (KERNEL_DS)
96 #define USER_DS TASK_SIZE
97 #define get_fs() (current_thread_info()->addr_limit)
99 static inline void set_fs(mm_segment_t fs)
101 current_thread_info()->addr_limit = fs;
102 modify_domain(DOMAIN_KERNEL, fs ? DOMAIN_CLIENT : DOMAIN_MANAGER);
105 #define segment_eq(a, b) ((a) == (b))
107 #define __addr_ok(addr) ({ \
108 unsigned long flag; \
109 __asm__("cmp %2, %0; movlo %0, #0" \
111 : "0" (current_thread_info()->addr_limit), "r" (addr) \
115 /* We use 33-bit arithmetic here... */
116 #define __range_ok(addr, size) ({ \
117 unsigned long flag, roksum; \
118 __chk_user_ptr(addr); \
119 __asm__("adds %1, %2, %3; sbcccs %1, %1, %0; movcc %0, #0" \
120 : "=&r" (flag), "=&r" (roksum) \
121 : "r" (addr), "Ir" (size), "0" (current_thread_info()->addr_limit) \
126 * Single-value transfer routines. They automatically use the right
127 * size if we just have the right pointer type. Note that the functions
128 * which read from user space (*get_*) need to take care not to leak
129 * kernel data even if the calling code is buggy and fails to check
130 * the return value. This means zeroing out the destination variable
131 * or buffer on error. Normally this is done out of line by the
132 * fixup code, but there are a few places where it intrudes on the
133 * main code path. When we only write to user space, there is no
136 extern int __get_user_1(void *);
137 extern int __get_user_2(void *);
138 extern int __get_user_4(void *);
139 extern int __get_user_32t_8(void *);
140 extern int __get_user_8(void *);
141 extern int __get_user_64t_1(void *);
142 extern int __get_user_64t_2(void *);
143 extern int __get_user_64t_4(void *);
145 #define __GUP_CLOBBER_1 "lr", "cc"
146 #ifdef CONFIG_CPU_USE_DOMAINS
147 #define __GUP_CLOBBER_2 "ip", "lr", "cc"
149 #define __GUP_CLOBBER_2 "lr", "cc"
151 #define __GUP_CLOBBER_4 "lr", "cc"
152 #define __GUP_CLOBBER_32t_8 "lr", "cc"
153 #define __GUP_CLOBBER_8 "lr", "cc"
155 #define __get_user_x(__r2, __p, __e, __l, __s) \
156 __asm__ __volatile__ ( \
157 __asmeq("%0", "r0") __asmeq("%1", "r2") \
158 __asmeq("%3", "r1") \
159 "bl __get_user_" #__s \
160 : "=&r" (__e), "=r" (__r2) \
161 : "0" (__p), "r" (__l) \
162 : __GUP_CLOBBER_##__s)
164 /* narrowing a double-word get into a single 32bit word register: */
166 #define __get_user_x_32t(__r2, __p, __e, __l, __s) \
167 __get_user_x(__r2, __p, __e, __l, 32t_8)
169 #define __get_user_x_32t __get_user_x
173 * storing result into proper least significant word of 64bit target var,
174 * different only for big endian case where 64 bit __r2 lsw is r3:
177 #define __get_user_x_64t(__r2, __p, __e, __l, __s) \
178 __asm__ __volatile__ ( \
179 __asmeq("%0", "r0") __asmeq("%1", "r2") \
180 __asmeq("%3", "r1") \
181 "bl __get_user_64t_" #__s \
182 : "=&r" (__e), "=r" (__r2) \
183 : "0" (__p), "r" (__l) \
184 : __GUP_CLOBBER_##__s)
186 #define __get_user_x_64t __get_user_x
190 #define __get_user_check(x, p) \
192 unsigned long __limit = current_thread_info()->addr_limit - 1; \
193 register const typeof(*(p)) __user *__p asm("r0") = (p);\
194 register typeof(x) __r2 asm("r2"); \
195 register unsigned long __l asm("r1") = __limit; \
196 register int __e asm("r0"); \
197 unsigned int __ua_flags = uaccess_save_and_enable(); \
198 switch (sizeof(*(__p))) { \
200 if (sizeof((x)) >= 8) \
201 __get_user_x_64t(__r2, __p, __e, __l, 1); \
203 __get_user_x(__r2, __p, __e, __l, 1); \
206 if (sizeof((x)) >= 8) \
207 __get_user_x_64t(__r2, __p, __e, __l, 2); \
209 __get_user_x(__r2, __p, __e, __l, 2); \
212 if (sizeof((x)) >= 8) \
213 __get_user_x_64t(__r2, __p, __e, __l, 4); \
215 __get_user_x(__r2, __p, __e, __l, 4); \
218 if (sizeof((x)) < 8) \
219 __get_user_x_32t(__r2, __p, __e, __l, 4); \
221 __get_user_x(__r2, __p, __e, __l, 8); \
223 default: __e = __get_user_bad(); break; \
225 uaccess_restore(__ua_flags); \
226 x = (typeof(*(p))) __r2; \
230 #define get_user(x, p) \
233 __get_user_check(x, p); \
236 extern int __put_user_1(void *, unsigned int);
237 extern int __put_user_2(void *, unsigned int);
238 extern int __put_user_4(void *, unsigned int);
239 extern int __put_user_8(void *, unsigned long long);
241 #define __put_user_x(__r2, __p, __e, __l, __s) \
242 __asm__ __volatile__ ( \
243 __asmeq("%0", "r0") __asmeq("%2", "r2") \
244 __asmeq("%3", "r1") \
245 "bl __put_user_" #__s \
247 : "0" (__p), "r" (__r2), "r" (__l) \
250 #define __put_user_check(x, p) \
252 unsigned long __limit = current_thread_info()->addr_limit - 1; \
253 const typeof(*(p)) __user *__tmp_p = (p); \
254 register const typeof(*(p)) __r2 asm("r2") = (x); \
255 register const typeof(*(p)) __user *__p asm("r0") = __tmp_p; \
256 register unsigned long __l asm("r1") = __limit; \
257 register int __e asm("r0"); \
258 unsigned int __ua_flags = uaccess_save_and_enable(); \
259 switch (sizeof(*(__p))) { \
261 __put_user_x(__r2, __p, __e, __l, 1); \
264 __put_user_x(__r2, __p, __e, __l, 2); \
267 __put_user_x(__r2, __p, __e, __l, 4); \
270 __put_user_x(__r2, __p, __e, __l, 8); \
272 default: __e = __put_user_bad(); break; \
274 uaccess_restore(__ua_flags); \
278 #define put_user(x, p) \
281 __put_user_check(x, p); \
284 #else /* CONFIG_MMU */
287 * uClinux has only one addr space, so has simplified address limits.
289 #define USER_DS KERNEL_DS
291 #define segment_eq(a, b) (1)
292 #define __addr_ok(addr) ((void)(addr), 1)
293 #define __range_ok(addr, size) ((void)(addr), 0)
294 #define get_fs() (KERNEL_DS)
296 static inline void set_fs(mm_segment_t fs)
300 #define get_user(x, p) __get_user(x, p)
301 #define put_user(x, p) __put_user(x, p)
303 #endif /* CONFIG_MMU */
305 #define access_ok(type, addr, size) (__range_ok(addr, size) == 0)
307 #define user_addr_max() \
308 (segment_eq(get_fs(), KERNEL_DS) ? ~0UL : get_fs())
311 * The "__xxx" versions of the user access functions do not verify the
312 * address space - it must have been done previously with a separate
313 * "access_ok()" call.
315 * The "xxx_error" versions set the third argument to EFAULT if an
316 * error occurs, and leave it unchanged on success. Note that these
317 * versions are void (ie, don't return a value as such).
319 #define __get_user(x, ptr) \
322 __get_user_err((x), (ptr), __gu_err); \
326 #define __get_user_error(x, ptr, err) \
328 __get_user_err((x), (ptr), err); \
332 #define __get_user_err(x, ptr, err) \
334 unsigned long __gu_addr = (unsigned long)(ptr); \
335 unsigned long __gu_val; \
336 unsigned int __ua_flags; \
337 __chk_user_ptr(ptr); \
339 __ua_flags = uaccess_save_and_enable(); \
340 switch (sizeof(*(ptr))) { \
341 case 1: __get_user_asm_byte(__gu_val, __gu_addr, err); break; \
342 case 2: __get_user_asm_half(__gu_val, __gu_addr, err); break; \
343 case 4: __get_user_asm_word(__gu_val, __gu_addr, err); break; \
344 default: (__gu_val) = __get_user_bad(); \
346 uaccess_restore(__ua_flags); \
347 (x) = (__typeof__(*(ptr)))__gu_val; \
350 #define __get_user_asm_byte(x, addr, err) \
351 __asm__ __volatile__( \
352 "1: " TUSER(ldrb) " %1,[%2],#0\n" \
354 " .pushsection .text.fixup,\"ax\"\n" \
360 " .pushsection __ex_table,\"a\"\n" \
364 : "+r" (err), "=&r" (x) \
365 : "r" (addr), "i" (-EFAULT) \
369 #define __get_user_asm_half(x, __gu_addr, err) \
371 unsigned long __b1, __b2; \
372 __get_user_asm_byte(__b1, __gu_addr, err); \
373 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
374 (x) = __b1 | (__b2 << 8); \
377 #define __get_user_asm_half(x, __gu_addr, err) \
379 unsigned long __b1, __b2; \
380 __get_user_asm_byte(__b1, __gu_addr, err); \
381 __get_user_asm_byte(__b2, __gu_addr + 1, err); \
382 (x) = (__b1 << 8) | __b2; \
386 #define __get_user_asm_word(x, addr, err) \
387 __asm__ __volatile__( \
388 "1: " TUSER(ldr) " %1,[%2],#0\n" \
390 " .pushsection .text.fixup,\"ax\"\n" \
396 " .pushsection __ex_table,\"a\"\n" \
400 : "+r" (err), "=&r" (x) \
401 : "r" (addr), "i" (-EFAULT) \
404 #define __put_user(x, ptr) \
407 __put_user_err((x), (ptr), __pu_err); \
411 #define __put_user_error(x, ptr, err) \
413 __put_user_err((x), (ptr), err); \
417 #define __put_user_err(x, ptr, err) \
419 unsigned long __pu_addr = (unsigned long)(ptr); \
420 unsigned int __ua_flags; \
421 __typeof__(*(ptr)) __pu_val = (x); \
422 __chk_user_ptr(ptr); \
424 __ua_flags = uaccess_save_and_enable(); \
425 switch (sizeof(*(ptr))) { \
426 case 1: __put_user_asm_byte(__pu_val, __pu_addr, err); break; \
427 case 2: __put_user_asm_half(__pu_val, __pu_addr, err); break; \
428 case 4: __put_user_asm_word(__pu_val, __pu_addr, err); break; \
429 case 8: __put_user_asm_dword(__pu_val, __pu_addr, err); break; \
430 default: __put_user_bad(); \
432 uaccess_restore(__ua_flags); \
435 #define __put_user_asm_byte(x, __pu_addr, err) \
436 __asm__ __volatile__( \
437 "1: " TUSER(strb) " %1,[%2],#0\n" \
439 " .pushsection .text.fixup,\"ax\"\n" \
444 " .pushsection __ex_table,\"a\"\n" \
449 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
453 #define __put_user_asm_half(x, __pu_addr, err) \
455 unsigned long __temp = (__force unsigned long)(x); \
456 __put_user_asm_byte(__temp, __pu_addr, err); \
457 __put_user_asm_byte(__temp >> 8, __pu_addr + 1, err); \
460 #define __put_user_asm_half(x, __pu_addr, err) \
462 unsigned long __temp = (__force unsigned long)(x); \
463 __put_user_asm_byte(__temp >> 8, __pu_addr, err); \
464 __put_user_asm_byte(__temp, __pu_addr + 1, err); \
468 #define __put_user_asm_word(x, __pu_addr, err) \
469 __asm__ __volatile__( \
470 "1: " TUSER(str) " %1,[%2],#0\n" \
472 " .pushsection .text.fixup,\"ax\"\n" \
477 " .pushsection __ex_table,\"a\"\n" \
482 : "r" (x), "r" (__pu_addr), "i" (-EFAULT) \
486 #define __reg_oper0 "%R2"
487 #define __reg_oper1 "%Q2"
489 #define __reg_oper0 "%Q2"
490 #define __reg_oper1 "%R2"
493 #define __put_user_asm_dword(x, __pu_addr, err) \
494 __asm__ __volatile__( \
495 ARM( "1: " TUSER(str) " " __reg_oper1 ", [%1], #4\n" ) \
496 ARM( "2: " TUSER(str) " " __reg_oper0 ", [%1]\n" ) \
497 THUMB( "1: " TUSER(str) " " __reg_oper1 ", [%1]\n" ) \
498 THUMB( "2: " TUSER(str) " " __reg_oper0 ", [%1, #4]\n" ) \
500 " .pushsection .text.fixup,\"ax\"\n" \
505 " .pushsection __ex_table,\"a\"\n" \
510 : "+r" (err), "+r" (__pu_addr) \
511 : "r" (x), "i" (-EFAULT) \
516 extern unsigned long __must_check
517 arm_copy_from_user(void *to, const void __user *from, unsigned long n);
519 static inline unsigned long __must_check
520 __copy_from_user(void *to, const void __user *from, unsigned long n)
522 unsigned int __ua_flags = uaccess_save_and_enable();
523 n = arm_copy_from_user(to, from, n);
524 uaccess_restore(__ua_flags);
528 extern unsigned long __must_check
529 arm_copy_to_user(void __user *to, const void *from, unsigned long n);
530 extern unsigned long __must_check
531 __copy_to_user_std(void __user *to, const void *from, unsigned long n);
533 static inline unsigned long __must_check
534 __copy_to_user(void __user *to, const void *from, unsigned long n)
536 unsigned int __ua_flags = uaccess_save_and_enable();
537 n = arm_copy_to_user(to, from, n);
538 uaccess_restore(__ua_flags);
542 extern unsigned long __must_check
543 arm_clear_user(void __user *addr, unsigned long n);
544 extern unsigned long __must_check
545 __clear_user_std(void __user *addr, unsigned long n);
547 static inline unsigned long __must_check
548 __clear_user(void __user *addr, unsigned long n)
550 unsigned int __ua_flags = uaccess_save_and_enable();
551 n = arm_clear_user(addr, n);
552 uaccess_restore(__ua_flags);
557 #define __copy_from_user(to, from, n) (memcpy(to, (void __force *)from, n), 0)
558 #define __copy_to_user(to, from, n) (memcpy((void __force *)to, from, n), 0)
559 #define __clear_user(addr, n) (memset((void __force *)addr, 0, n), 0)
562 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
564 if (access_ok(VERIFY_READ, from, n))
565 n = __copy_from_user(to, from, n);
566 else /* security hole - plug it */
571 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
573 if (access_ok(VERIFY_WRITE, to, n))
574 n = __copy_to_user(to, from, n);
578 #define __copy_to_user_inatomic __copy_to_user
579 #define __copy_from_user_inatomic __copy_from_user
581 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
583 if (access_ok(VERIFY_WRITE, to, n))
584 n = __clear_user(to, n);
588 /* These are from lib/ code, and use __get_user() and friends */
589 extern long strncpy_from_user(char *dest, const char __user *src, long count);
591 extern __must_check long strlen_user(const char __user *str);
592 extern __must_check long strnlen_user(const char __user *str, long n);
594 #endif /* _ASMARM_UACCESS_H */