1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * uaccess.h: User space memore access functions. 4 * 5 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu) 6 * Copyright (C) 1996,1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz) 7 */ 8 #ifndef _ASM_UACCESS_H 9 #define _ASM_UACCESS_H 10 11 #include <linux/compiler.h> 12 #include <linux/string.h> 13 14 #include <asm/processor.h> 15 16 #define ARCH_HAS_SORT_EXTABLE 17 #define ARCH_HAS_SEARCH_EXTABLE 18 19 /* Sparc is not segmented, however we need to be able to fool access_ok() 20 * when doing system calls from kernel mode legitimately. 21 * 22 * "For historical reasons, these macros are grossly misnamed." -Linus 23 */ 24 25 #define KERNEL_DS ((mm_segment_t) { 0 }) 26 #define USER_DS ((mm_segment_t) { -1 }) 27 28 #define get_ds() (KERNEL_DS) 29 #define get_fs() (current->thread.current_ds) 30 #define set_fs(val) ((current->thread.current_ds) = (val)) 31 32 #define segment_eq(a, b) ((a).seg == (b).seg) 33 34 /* We have there a nice not-mapped page at PAGE_OFFSET - PAGE_SIZE, so that this test 35 * can be fairly lightweight. 36 * No one can read/write anything from userland in the kernel space by setting 37 * large size and address near to PAGE_OFFSET - a fault will break his intentions. 38 */ 39 #define __user_ok(addr, size) ({ (void)(size); (addr) < STACK_TOP; }) 40 #define __kernel_ok (uaccess_kernel()) 41 #define __access_ok(addr, size) (__user_ok((addr) & get_fs().seg, (size))) 42 #define access_ok(addr, size) __access_ok((unsigned long)(addr), size) 43 44 /* 45 * The exception table consists of pairs of addresses: the first is the 46 * address of an instruction that is allowed to fault, and the second is 47 * the address at which the program should continue. No registers are 48 * modified, so it is entirely up to the continuation code to figure out 49 * what to do. 50 * 51 * All the routines below use bits of fixup code that are out of line 52 * with the main instruction path. This means when everything is well, 53 * we don't even have to jump over them. Further, they do not intrude 54 * on our cache or tlb entries. 55 * 56 * There is a special way how to put a range of potentially faulting 57 * insns (like twenty ldd/std's with now intervening other instructions) 58 * You specify address of first in insn and 0 in fixup and in the next 59 * exception_table_entry you specify last potentially faulting insn + 1 60 * and in fixup the routine which should handle the fault. 61 * That fixup code will get 62 * (faulting_insn_address - first_insn_in_the_range_address)/4 63 * in %g2 (ie. index of the faulting instruction in the range). 64 */ 65 66 struct exception_table_entry 67 { 68 unsigned long insn, fixup; 69 }; 70 71 /* Returns 0 if exception not found and fixup otherwise. */ 72 unsigned long search_extables_range(unsigned long addr, unsigned long *g2); 73 74 /* Uh, these should become the main single-value transfer routines.. 75 * They automatically use the right size if we just have the right 76 * pointer type.. 77 * 78 * This gets kind of ugly. We want to return _two_ values in "get_user()" 79 * and yet we don't want to do any pointers, because that is too much 80 * of a performance impact. Thus we have a few rather ugly macros here, 81 * and hide all the ugliness from the user. 82 */ 83 #define put_user(x, ptr) ({ \ 84 unsigned long __pu_addr = (unsigned long)(ptr); \ 85 __chk_user_ptr(ptr); \ 86 __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \ 87 }) 88 89 #define get_user(x, ptr) ({ \ 90 unsigned long __gu_addr = (unsigned long)(ptr); \ 91 __chk_user_ptr(ptr); \ 92 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \ 93 }) 94 95 /* 96 * The "__xxx" versions do not do address space checking, useful when 97 * doing multiple accesses to the same area (the user has to do the 98 * checks by hand with "access_ok()") 99 */ 100 #define __put_user(x, ptr) \ 101 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 102 #define __get_user(x, ptr) \ 103 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr))) 104 105 struct __large_struct { unsigned long buf[100]; }; 106 #define __m(x) ((struct __large_struct __user *)(x)) 107 108 #define __put_user_check(x, addr, size) ({ \ 109 register int __pu_ret; \ 110 if (__access_ok(addr, size)) { \ 111 switch (size) { \ 112 case 1: \ 113 __put_user_asm(x, b, addr, __pu_ret); \ 114 break; \ 115 case 2: \ 116 __put_user_asm(x, h, addr, __pu_ret); \ 117 break; \ 118 case 4: \ 119 __put_user_asm(x, , addr, __pu_ret); \ 120 break; \ 121 case 8: \ 122 __put_user_asm(x, d, addr, __pu_ret); \ 123 break; \ 124 default: \ 125 __pu_ret = __put_user_bad(); \ 126 break; \ 127 } \ 128 } else { \ 129 __pu_ret = -EFAULT; \ 130 } \ 131 __pu_ret; \ 132 }) 133 134 #define __put_user_nocheck(x, addr, size) ({ \ 135 register int __pu_ret; \ 136 switch (size) { \ 137 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \ 138 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \ 139 case 4: __put_user_asm(x, , addr, __pu_ret); break; \ 140 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \ 141 default: __pu_ret = __put_user_bad(); break; \ 142 } \ 143 __pu_ret; \ 144 }) 145 146 #define __put_user_asm(x, size, addr, ret) \ 147 __asm__ __volatile__( \ 148 "/* Put user asm, inline. */\n" \ 149 "1:\t" "st"#size " %1, %2\n\t" \ 150 "clr %0\n" \ 151 "2:\n\n\t" \ 152 ".section .fixup,#alloc,#execinstr\n\t" \ 153 ".align 4\n" \ 154 "3:\n\t" \ 155 "b 2b\n\t" \ 156 " mov %3, %0\n\t" \ 157 ".previous\n\n\t" \ 158 ".section __ex_table,#alloc\n\t" \ 159 ".align 4\n\t" \ 160 ".word 1b, 3b\n\t" \ 161 ".previous\n\n\t" \ 162 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ 163 "i" (-EFAULT)) 164 165 int __put_user_bad(void); 166 167 #define __get_user_check(x, addr, size, type) ({ \ 168 register int __gu_ret; \ 169 register unsigned long __gu_val; \ 170 if (__access_ok(addr, size)) { \ 171 switch (size) { \ 172 case 1: \ 173 __get_user_asm(__gu_val, ub, addr, __gu_ret); \ 174 break; \ 175 case 2: \ 176 __get_user_asm(__gu_val, uh, addr, __gu_ret); \ 177 break; \ 178 case 4: \ 179 __get_user_asm(__gu_val, , addr, __gu_ret); \ 180 break; \ 181 case 8: \ 182 __get_user_asm(__gu_val, d, addr, __gu_ret); \ 183 break; \ 184 default: \ 185 __gu_val = 0; \ 186 __gu_ret = __get_user_bad(); \ 187 break; \ 188 } \ 189 } else { \ 190 __gu_val = 0; \ 191 __gu_ret = -EFAULT; \ 192 } \ 193 x = (__force type) __gu_val; \ 194 __gu_ret; \ 195 }) 196 197 #define __get_user_nocheck(x, addr, size, type) ({ \ 198 register int __gu_ret; \ 199 register unsigned long __gu_val; \ 200 switch (size) { \ 201 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \ 202 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \ 203 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \ 204 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \ 205 default: \ 206 __gu_val = 0; \ 207 __gu_ret = __get_user_bad(); \ 208 break; \ 209 } \ 210 x = (__force type) __gu_val; \ 211 __gu_ret; \ 212 }) 213 214 #define __get_user_asm(x, size, addr, ret) \ 215 __asm__ __volatile__( \ 216 "/* Get user asm, inline. */\n" \ 217 "1:\t" "ld"#size " %2, %1\n\t" \ 218 "clr %0\n" \ 219 "2:\n\n\t" \ 220 ".section .fixup,#alloc,#execinstr\n\t" \ 221 ".align 4\n" \ 222 "3:\n\t" \ 223 "clr %1\n\t" \ 224 "b 2b\n\t" \ 225 " mov %3, %0\n\n\t" \ 226 ".previous\n\t" \ 227 ".section __ex_table,#alloc\n\t" \ 228 ".align 4\n\t" \ 229 ".word 1b, 3b\n\n\t" \ 230 ".previous\n\t" \ 231 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ 232 "i" (-EFAULT)) 233 234 int __get_user_bad(void); 235 236 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); 237 238 static inline unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) 239 { 240 return __copy_user(to, (__force void __user *) from, n); 241 } 242 243 static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) 244 { 245 return __copy_user((__force void __user *) to, from, n); 246 } 247 248 #define INLINE_COPY_FROM_USER 249 #define INLINE_COPY_TO_USER 250 251 static inline unsigned long __clear_user(void __user *addr, unsigned long size) 252 { 253 unsigned long ret; 254 255 __asm__ __volatile__ ( 256 ".section __ex_table,#alloc\n\t" 257 ".align 4\n\t" 258 ".word 1f,3\n\t" 259 ".previous\n\t" 260 "mov %2, %%o1\n" 261 "1:\n\t" 262 "call __bzero\n\t" 263 " mov %1, %%o0\n\t" 264 "mov %%o0, %0\n" 265 : "=r" (ret) : "r" (addr), "r" (size) : 266 "o0", "o1", "o2", "o3", "o4", "o5", "o7", 267 "g1", "g2", "g3", "g4", "g5", "g7", "cc"); 268 269 return ret; 270 } 271 272 static inline unsigned long clear_user(void __user *addr, unsigned long n) 273 { 274 if (n && __access_ok((unsigned long) addr, n)) 275 return __clear_user(addr, n); 276 else 277 return n; 278 } 279 280 __must_check long strnlen_user(const char __user *str, long n); 281 282 #endif /* _ASM_UACCESS_H */ 283