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(type, addr, size) \ 43 ({ (void)(type); __access_ok((unsigned long)(addr), size); }) 44 45 /* 46 * The exception table consists of pairs of addresses: the first is the 47 * address of an instruction that is allowed to fault, and the second is 48 * the address at which the program should continue. No registers are 49 * modified, so it is entirely up to the continuation code to figure out 50 * what to do. 51 * 52 * All the routines below use bits of fixup code that are out of line 53 * with the main instruction path. This means when everything is well, 54 * we don't even have to jump over them. Further, they do not intrude 55 * on our cache or tlb entries. 56 * 57 * There is a special way how to put a range of potentially faulting 58 * insns (like twenty ldd/std's with now intervening other instructions) 59 * You specify address of first in insn and 0 in fixup and in the next 60 * exception_table_entry you specify last potentially faulting insn + 1 61 * and in fixup the routine which should handle the fault. 62 * That fixup code will get 63 * (faulting_insn_address - first_insn_in_the_range_address)/4 64 * in %g2 (ie. index of the faulting instruction in the range). 65 */ 66 67 struct exception_table_entry 68 { 69 unsigned long insn, fixup; 70 }; 71 72 /* Returns 0 if exception not found and fixup otherwise. */ 73 unsigned long search_extables_range(unsigned long addr, unsigned long *g2); 74 75 /* Uh, these should become the main single-value transfer routines.. 76 * They automatically use the right size if we just have the right 77 * pointer type.. 78 * 79 * This gets kind of ugly. We want to return _two_ values in "get_user()" 80 * and yet we don't want to do any pointers, because that is too much 81 * of a performance impact. Thus we have a few rather ugly macros here, 82 * and hide all the ugliness from the user. 83 */ 84 #define put_user(x, ptr) ({ \ 85 unsigned long __pu_addr = (unsigned long)(ptr); \ 86 __chk_user_ptr(ptr); \ 87 __put_user_check((__typeof__(*(ptr)))(x), __pu_addr, sizeof(*(ptr))); \ 88 }) 89 90 #define get_user(x, ptr) ({ \ 91 unsigned long __gu_addr = (unsigned long)(ptr); \ 92 __chk_user_ptr(ptr); \ 93 __get_user_check((x), __gu_addr, sizeof(*(ptr)), __typeof__(*(ptr))); \ 94 }) 95 96 /* 97 * The "__xxx" versions do not do address space checking, useful when 98 * doing multiple accesses to the same area (the user has to do the 99 * checks by hand with "access_ok()") 100 */ 101 #define __put_user(x, ptr) \ 102 __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) 103 #define __get_user(x, ptr) \ 104 __get_user_nocheck((x), (ptr), sizeof(*(ptr)), __typeof__(*(ptr))) 105 106 struct __large_struct { unsigned long buf[100]; }; 107 #define __m(x) ((struct __large_struct __user *)(x)) 108 109 #define __put_user_check(x, addr, size) ({ \ 110 register int __pu_ret; \ 111 if (__access_ok(addr, size)) { \ 112 switch (size) { \ 113 case 1: \ 114 __put_user_asm(x, b, addr, __pu_ret); \ 115 break; \ 116 case 2: \ 117 __put_user_asm(x, h, addr, __pu_ret); \ 118 break; \ 119 case 4: \ 120 __put_user_asm(x, , addr, __pu_ret); \ 121 break; \ 122 case 8: \ 123 __put_user_asm(x, d, addr, __pu_ret); \ 124 break; \ 125 default: \ 126 __pu_ret = __put_user_bad(); \ 127 break; \ 128 } \ 129 } else { \ 130 __pu_ret = -EFAULT; \ 131 } \ 132 __pu_ret; \ 133 }) 134 135 #define __put_user_nocheck(x, addr, size) ({ \ 136 register int __pu_ret; \ 137 switch (size) { \ 138 case 1: __put_user_asm(x, b, addr, __pu_ret); break; \ 139 case 2: __put_user_asm(x, h, addr, __pu_ret); break; \ 140 case 4: __put_user_asm(x, , addr, __pu_ret); break; \ 141 case 8: __put_user_asm(x, d, addr, __pu_ret); break; \ 142 default: __pu_ret = __put_user_bad(); break; \ 143 } \ 144 __pu_ret; \ 145 }) 146 147 #define __put_user_asm(x, size, addr, ret) \ 148 __asm__ __volatile__( \ 149 "/* Put user asm, inline. */\n" \ 150 "1:\t" "st"#size " %1, %2\n\t" \ 151 "clr %0\n" \ 152 "2:\n\n\t" \ 153 ".section .fixup,#alloc,#execinstr\n\t" \ 154 ".align 4\n" \ 155 "3:\n\t" \ 156 "b 2b\n\t" \ 157 " mov %3, %0\n\t" \ 158 ".previous\n\n\t" \ 159 ".section __ex_table,#alloc\n\t" \ 160 ".align 4\n\t" \ 161 ".word 1b, 3b\n\t" \ 162 ".previous\n\n\t" \ 163 : "=&r" (ret) : "r" (x), "m" (*__m(addr)), \ 164 "i" (-EFAULT)) 165 166 int __put_user_bad(void); 167 168 #define __get_user_check(x, addr, size, type) ({ \ 169 register int __gu_ret; \ 170 register unsigned long __gu_val; \ 171 if (__access_ok(addr, size)) { \ 172 switch (size) { \ 173 case 1: \ 174 __get_user_asm(__gu_val, ub, addr, __gu_ret); \ 175 break; \ 176 case 2: \ 177 __get_user_asm(__gu_val, uh, addr, __gu_ret); \ 178 break; \ 179 case 4: \ 180 __get_user_asm(__gu_val, , addr, __gu_ret); \ 181 break; \ 182 case 8: \ 183 __get_user_asm(__gu_val, d, addr, __gu_ret); \ 184 break; \ 185 default: \ 186 __gu_val = 0; \ 187 __gu_ret = __get_user_bad(); \ 188 break; \ 189 } \ 190 } else { \ 191 __gu_val = 0; \ 192 __gu_ret = -EFAULT; \ 193 } \ 194 x = (__force type) __gu_val; \ 195 __gu_ret; \ 196 }) 197 198 #define __get_user_nocheck(x, addr, size, type) ({ \ 199 register int __gu_ret; \ 200 register unsigned long __gu_val; \ 201 switch (size) { \ 202 case 1: __get_user_asm(__gu_val, ub, addr, __gu_ret); break; \ 203 case 2: __get_user_asm(__gu_val, uh, addr, __gu_ret); break; \ 204 case 4: __get_user_asm(__gu_val, , addr, __gu_ret); break; \ 205 case 8: __get_user_asm(__gu_val, d, addr, __gu_ret); break; \ 206 default: \ 207 __gu_val = 0; \ 208 __gu_ret = __get_user_bad(); \ 209 break; \ 210 } \ 211 x = (__force type) __gu_val; \ 212 __gu_ret; \ 213 }) 214 215 #define __get_user_asm(x, size, addr, ret) \ 216 __asm__ __volatile__( \ 217 "/* Get user asm, inline. */\n" \ 218 "1:\t" "ld"#size " %2, %1\n\t" \ 219 "clr %0\n" \ 220 "2:\n\n\t" \ 221 ".section .fixup,#alloc,#execinstr\n\t" \ 222 ".align 4\n" \ 223 "3:\n\t" \ 224 "clr %1\n\t" \ 225 "b 2b\n\t" \ 226 " mov %3, %0\n\n\t" \ 227 ".previous\n\t" \ 228 ".section __ex_table,#alloc\n\t" \ 229 ".align 4\n\t" \ 230 ".word 1b, 3b\n\n\t" \ 231 ".previous\n\t" \ 232 : "=&r" (ret), "=&r" (x) : "m" (*__m(addr)), \ 233 "i" (-EFAULT)) 234 235 int __get_user_bad(void); 236 237 unsigned long __copy_user(void __user *to, const void __user *from, unsigned long size); 238 239 static inline unsigned long raw_copy_to_user(void __user *to, const void *from, unsigned long n) 240 { 241 return __copy_user(to, (__force void __user *) from, n); 242 } 243 244 static inline unsigned long raw_copy_from_user(void *to, const void __user *from, unsigned long n) 245 { 246 return __copy_user((__force void __user *) to, from, n); 247 } 248 249 #define INLINE_COPY_FROM_USER 250 #define INLINE_COPY_TO_USER 251 252 static inline unsigned long __clear_user(void __user *addr, unsigned long size) 253 { 254 unsigned long ret; 255 256 __asm__ __volatile__ ( 257 ".section __ex_table,#alloc\n\t" 258 ".align 4\n\t" 259 ".word 1f,3\n\t" 260 ".previous\n\t" 261 "mov %2, %%o1\n" 262 "1:\n\t" 263 "call __bzero\n\t" 264 " mov %1, %%o0\n\t" 265 "mov %%o0, %0\n" 266 : "=r" (ret) : "r" (addr), "r" (size) : 267 "o0", "o1", "o2", "o3", "o4", "o5", "o7", 268 "g1", "g2", "g3", "g4", "g5", "g7", "cc"); 269 270 return ret; 271 } 272 273 static inline unsigned long clear_user(void __user *addr, unsigned long n) 274 { 275 if (n && __access_ok((unsigned long) addr, n)) 276 return __clear_user(addr, n); 277 else 278 return n; 279 } 280 281 __must_check long strnlen_user(const char __user *str, long n); 282 283 #endif /* _ASM_UACCESS_H */ 284