2 * Based on arch/arm/include/asm/uaccess.h
4 * Copyright (C) 2012 ARM Ltd.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 #ifndef __ASM_UACCESS_H
19 #define __ASM_UACCESS_H
22 * User space memory access functions
24 #include <linux/string.h>
25 #include <linux/thread_info.h>
27 #include <asm/alternative.h>
28 #include <asm/cpufeature.h>
29 #include <asm/ptrace.h>
30 #include <asm/sysreg.h>
31 #include <asm/errno.h>
32 #include <asm/memory.h>
33 #include <asm/compiler.h>
36 #define VERIFY_WRITE 1
39 * The exception table consists of pairs of relative offsets: the first
40 * is the relative offset to an instruction that is allowed to fault,
41 * and the second is the relative offset at which the program should
42 * continue. No registers are modified, so it is entirely up to the
43 * continuation code to figure out what to do.
45 * All the routines below use bits of fixup code that are out of line
46 * with the main instruction path. This means when everything is well,
47 * we don't even have to jump over them. Further, they do not intrude
48 * on our cache or tlb entries.
51 struct exception_table_entry
56 #define ARCH_HAS_RELATIVE_EXTABLE
58 extern int fixup_exception(struct pt_regs *regs);
60 #define KERNEL_DS (-1UL)
61 #define get_ds() (KERNEL_DS)
63 #define USER_DS TASK_SIZE_64
64 #define get_fs() (current_thread_info()->addr_limit)
66 static inline void set_fs(mm_segment_t fs)
68 current_thread_info()->addr_limit = fs;
71 * Enable/disable UAO so that copy_to_user() etc can access
72 * kernel memory with the unprivileged instructions.
74 if (IS_ENABLED(CONFIG_ARM64_UAO) && fs == KERNEL_DS)
75 asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO));
77 asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO,
81 #define segment_eq(a, b) ((a) == (b))
84 * Return 1 if addr < current->addr_limit, 0 otherwise.
86 #define __addr_ok(addr) \
89 asm("cmp %1, %0; cset %0, lo" \
91 : "r" (addr), "0" (current_thread_info()->addr_limit) \
97 * Test whether a block of memory is a valid user space address.
98 * Returns 1 if the range is valid, 0 otherwise.
100 * This is equivalent to the following test:
101 * (u65)addr + (u65)size <= current->addr_limit
103 * This needs 65-bit arithmetic.
105 #define __range_ok(addr, size) \
107 unsigned long __addr = (unsigned long __force)(addr); \
108 unsigned long flag, roksum; \
109 __chk_user_ptr(addr); \
110 asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls" \
111 : "=&r" (flag), "=&r" (roksum) \
112 : "1" (__addr), "Ir" (size), \
113 "r" (current_thread_info()->addr_limit) \
118 #define access_ok(type, addr, size) __range_ok(addr, size)
119 #define user_addr_max get_fs
121 #define _ASM_EXTABLE(from, to) \
122 " .pushsection __ex_table, \"a\"\n" \
124 " .long (" #from " - .), (" #to " - .)\n" \
128 * The "__xxx" versions of the user access functions do not verify the address
129 * space - it must have been done previously with a separate "access_ok()"
132 * The "__xxx_error" versions set the third argument to -EFAULT if an error
133 * occurs, and leave it unchanged on success.
135 #define __get_user_asm(instr, alt_instr, reg, x, addr, err, feature) \
137 "1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \
138 alt_instr " " reg "1, [%2]\n", feature) \
140 " .section .fixup, \"ax\"\n" \
146 _ASM_EXTABLE(1b, 3b) \
147 : "+r" (err), "=&r" (x) \
148 : "r" (addr), "i" (-EFAULT))
150 #define __get_user_err(x, ptr, err) \
152 unsigned long __gu_val; \
153 __chk_user_ptr(ptr); \
154 asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
155 CONFIG_ARM64_PAN)); \
156 switch (sizeof(*(ptr))) { \
158 __get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \
159 (err), ARM64_HAS_UAO); \
162 __get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr), \
163 (err), ARM64_HAS_UAO); \
166 __get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr), \
167 (err), ARM64_HAS_UAO); \
170 __get_user_asm("ldr", "ldtr", "%", __gu_val, (ptr), \
171 (err), ARM64_HAS_UAO); \
176 (x) = (__force __typeof__(*(ptr)))__gu_val; \
177 asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
178 CONFIG_ARM64_PAN)); \
181 #define __get_user(x, ptr) \
184 __get_user_err((x), (ptr), __gu_err); \
188 #define __get_user_error(x, ptr, err) \
190 __get_user_err((x), (ptr), (err)); \
194 #define __get_user_unaligned __get_user
196 #define get_user(x, ptr) \
198 __typeof__(*(ptr)) __user *__p = (ptr); \
200 access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \
201 __get_user((x), __p) : \
202 ((x) = 0, -EFAULT); \
205 #define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature) \
207 "1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \
208 alt_instr " " reg "1, [%2]\n", feature) \
210 " .section .fixup,\"ax\"\n" \
215 _ASM_EXTABLE(1b, 3b) \
217 : "r" (x), "r" (addr), "i" (-EFAULT))
219 #define __put_user_err(x, ptr, err) \
221 __typeof__(*(ptr)) __pu_val = (x); \
222 __chk_user_ptr(ptr); \
223 asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
224 CONFIG_ARM64_PAN)); \
225 switch (sizeof(*(ptr))) { \
227 __put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \
228 (err), ARM64_HAS_UAO); \
231 __put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr), \
232 (err), ARM64_HAS_UAO); \
235 __put_user_asm("str", "sttr", "%w", __pu_val, (ptr), \
236 (err), ARM64_HAS_UAO); \
239 __put_user_asm("str", "sttr", "%", __pu_val, (ptr), \
240 (err), ARM64_HAS_UAO); \
245 asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
246 CONFIG_ARM64_PAN)); \
249 #define __put_user(x, ptr) \
252 __put_user_err((x), (ptr), __pu_err); \
256 #define __put_user_error(x, ptr, err) \
258 __put_user_err((x), (ptr), (err)); \
262 #define __put_user_unaligned __put_user
264 #define put_user(x, ptr) \
266 __typeof__(*(ptr)) __user *__p = (ptr); \
268 access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \
269 __put_user((x), __p) : \
273 extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
274 extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
275 extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
276 extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
278 static inline unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n)
280 check_object_size(to, n, false);
281 return __arch_copy_from_user(to, from, n);
284 static inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n)
286 check_object_size(from, n, true);
287 return __arch_copy_to_user(to, from, n);
290 static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
292 if (access_ok(VERIFY_READ, from, n)) {
293 check_object_size(to, n, false);
294 n = __arch_copy_from_user(to, from, n);
295 } else /* security hole - plug it */
300 static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
302 if (access_ok(VERIFY_WRITE, to, n)) {
303 check_object_size(from, n, true);
304 n = __arch_copy_to_user(to, from, n);
309 static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n)
311 if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
312 n = __copy_in_user(to, from, n);
316 #define __copy_to_user_inatomic __copy_to_user
317 #define __copy_from_user_inatomic __copy_from_user
319 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
321 if (access_ok(VERIFY_WRITE, to, n))
322 n = __clear_user(to, n);
326 extern long strncpy_from_user(char *dest, const char __user *src, long count);
328 extern __must_check long strlen_user(const char __user *str);
329 extern __must_check long strnlen_user(const char __user *str, long n);
331 #endif /* __ASM_UACCESS_H */