arch/sparc/include/asm/uaccess_32.h

   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 */