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