arch/powerpc/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ARCH_POWERPC_UACCESS_H
   3 #define _ARCH_POWERPC_UACCESS_H
   4
   5 #include <asm/asm-compat.h>
   6 #include <asm/ppc_asm.h>
   7 #include <asm/processor.h>
   8 #include <asm/page.h>
   9 #include <asm/extable.h>
  10
  11 /*
  12  * The fs value determines whether argument validity checking should be
  13  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  14  * get_fs() == KERNEL_DS, checking is bypassed.
  15  *
  16  * For historical reasons, these macros are grossly misnamed.
  17  *
  18  * The fs/ds values are now the highest legal address in the "segment".
  19  * This simplifies the checking in the routines below.
  20  */
  21
  22 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  23
  24 #define KERNEL_DS       MAKE_MM_SEG(~0UL)
  25 #ifdef __powerpc64__
  26 /* We use TASK_SIZE_USER64 as TASK_SIZE is not constant */
  27 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_USER64 - 1)
  28 #else
  29 #define USER_DS         MAKE_MM_SEG(TASK_SIZE - 1)
  30 #endif
  31
  32 #define get_ds()        (KERNEL_DS)
  33 #define get_fs()        (current->thread.fs)
  34 #define set_fs(val)     (current->thread.fs = (val))
  35
  36 #define segment_eq(a, b)        ((a).seg == (b).seg)
  37
  38 #define user_addr_max() (get_fs().seg)
  39
  40 #ifdef __powerpc64__
  41 /*
  42  * This check is sufficient because there is a large enough
  43  * gap between user addresses and the kernel addresses
  44  */
  45 #define __access_ok(addr, size, segment)        \
  46         (((addr) <= (segment).seg) && ((size) <= (segment).seg))
  47
  48 #else
  49
  50 #define __access_ok(addr, size, segment)        \
  51         (((addr) <= (segment).seg) &&           \
  52          (((size) == 0) || (((size) - 1) <= ((segment).seg - (addr)))))
  53
  54 #endif
  55
  56 #define access_ok(type, addr, size)             \
  57         (__chk_user_ptr(addr),                  \
  58          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  59
  60 /*
  61  * These are the main single-value transfer routines.  They automatically
  62  * use the right size if we just have the right pointer type.
  63  *
  64  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  65  * and yet we don't want to do any pointers, because that is too much
  66  * of a performance impact. Thus we have a few rather ugly macros here,
  67  * and hide all the ugliness from the user.
  68  *
  69  * The "__xxx" versions of the user access functions are versions that
  70  * do not verify the address space, that must have been done previously
  71  * with a separate "access_ok()" call (this is used when we do multiple
  72  * accesses to the same area of user memory).
  73  *
  74  * As we use the same address space for kernel and user data on the
  75  * PowerPC, we can just do these as direct assignments.  (Of course, the
  76  * exception handling means that it's no longer "just"...)
  77  *
  78  */
  79 #define get_user(x, ptr) \
  80         __get_user_check((x), (ptr), sizeof(*(ptr)))
  81 #define put_user(x, ptr) \
  82         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  83
  84 #define __get_user(x, ptr) \
  85         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  86 #define __put_user(x, ptr) \
  87         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  88
  89 #define __get_user_inatomic(x, ptr) \
  90         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
  91 #define __put_user_inatomic(x, ptr) \
  92         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  93
  94 extern long __put_user_bad(void);
  95
  96 /*
  97  * We don't tell gcc that we are accessing memory, but this is OK
  98  * because we do not write to any memory gcc knows about, so there
  99  * are no aliasing issues.
 100  */
 101 #define __put_user_asm(x, addr, err, op)                        \
 102         __asm__ __volatile__(                                   \
 103                 "1:     " op " %1,0(%2) # put_user\n"           \
 104                 "2:\n"                                          \
 105                 ".section .fixup,\"ax\"\n"                      \
 106                 "3:     li %0,%3\n"                             \
 107                 "       b 2b\n"                                 \
 108                 ".previous\n"                                   \
 109                 EX_TABLE(1b, 3b)                                \
 110                 : "=r" (err)                                    \
 111                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 112
 113 #ifdef __powerpc64__
 114 #define __put_user_asm2(x, ptr, retval)                         \
 115           __put_user_asm(x, ptr, retval, "std")
 116 #else /* __powerpc64__ */
 117 #define __put_user_asm2(x, addr, err)                           \
 118         __asm__ __volatile__(                                   \
 119                 "1:     stw %1,0(%2)\n"                         \
 120                 "2:     stw %1+1,4(%2)\n"                       \
 121                 "3:\n"                                          \
 122                 ".section .fixup,\"ax\"\n"                      \
 123                 "4:     li %0,%3\n"                             \
 124                 "       b 3b\n"                                 \
 125                 ".previous\n"                                   \
 126                 EX_TABLE(1b, 4b)                                \
 127                 EX_TABLE(2b, 4b)                                \
 128                 : "=r" (err)                                    \
 129                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 130 #endif /* __powerpc64__ */
 131
 132 #define __put_user_size(x, ptr, size, retval)                   \
 133 do {                                                            \
 134         retval = 0;                                             \
 135         switch (size) {                                         \
 136           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 137           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 138           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 139           case 8: __put_user_asm2(x, ptr, retval); break;       \
 140           default: __put_user_bad();                            \
 141         }                                                       \
 142 } while (0)
 143
 144 #define __put_user_nocheck(x, ptr, size)                        \
 145 ({                                                              \
 146         long __pu_err;                                          \
 147         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 148         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 149                 might_fault();                                  \
 150         __chk_user_ptr(ptr);                                    \
 151         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 152         __pu_err;                                               \
 153 })
 154
 155 #define __put_user_check(x, ptr, size)                                  \
 156 ({                                                                      \
 157         long __pu_err = -EFAULT;                                        \
 158         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 159         might_fault();                                                  \
 160         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 161                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 162         __pu_err;                                                       \
 163 })
 164
 165 #define __put_user_nosleep(x, ptr, size)                        \
 166 ({                                                              \
 167         long __pu_err;                                          \
 168         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 169         __chk_user_ptr(ptr);                                    \
 170         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 171         __pu_err;                                               \
 172 })
 173
 174
 175 extern long __get_user_bad(void);
 176
 177 #define __get_user_asm(x, addr, err, op)                \
 178         __asm__ __volatile__(                           \
 179                 "1:     "op" %1,0(%2)   # get_user\n"   \
 180                 "2:\n"                                  \
 181                 ".section .fixup,\"ax\"\n"              \
 182                 "3:     li %0,%3\n"                     \
 183                 "       li %1,0\n"                      \
 184                 "       b 2b\n"                         \
 185                 ".previous\n"                           \
 186                 EX_TABLE(1b, 3b)                        \
 187                 : "=r" (err), "=r" (x)                  \
 188                 : "b" (addr), "i" (-EFAULT), "0" (err))
 189
 190 #ifdef __powerpc64__
 191 #define __get_user_asm2(x, addr, err)                   \
 192         __get_user_asm(x, addr, err, "ld")
 193 #else /* __powerpc64__ */
 194 #define __get_user_asm2(x, addr, err)                   \
 195         __asm__ __volatile__(                           \
 196                 "1:     lwz %1,0(%2)\n"                 \
 197                 "2:     lwz %1+1,4(%2)\n"               \
 198                 "3:\n"                                  \
 199                 ".section .fixup,\"ax\"\n"              \
 200                 "4:     li %0,%3\n"                     \
 201                 "       li %1,0\n"                      \
 202                 "       li %1+1,0\n"                    \
 203                 "       b 3b\n"                         \
 204                 ".previous\n"                           \
 205                 EX_TABLE(1b, 4b)                        \
 206                 EX_TABLE(2b, 4b)                        \
 207                 : "=r" (err), "=&r" (x)                 \
 208                 : "b" (addr), "i" (-EFAULT), "0" (err))
 209 #endif /* __powerpc64__ */
 210
 211 #define __get_user_size(x, ptr, size, retval)                   \
 212 do {                                                            \
 213         retval = 0;                                             \
 214         __chk_user_ptr(ptr);                                    \
 215         if (size > sizeof(x))                                   \
 216                 (x) = __get_user_bad();                         \
 217         switch (size) {                                         \
 218         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 219         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 220         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 221         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 222         default: (x) = __get_user_bad();                        \
 223         }                                                       \
 224 } while (0)
 225
 226 #define __get_user_nocheck(x, ptr, size)                        \
 227 ({                                                              \
 228         long __gu_err;                                          \
 229         unsigned long __gu_val;                                 \
 230         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 231         __chk_user_ptr(ptr);                                    \
 232         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 233                 might_fault();                                  \
 234         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 235         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 236         __gu_err;                                               \
 237 })
 238
 239 #define __get_user_check(x, ptr, size)                                  \
 240 ({                                                                      \
 241         long __gu_err = -EFAULT;                                        \
 242         unsigned long  __gu_val = 0;                                    \
 243         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 244         might_fault();                                                  \
 245         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 246                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 247         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 248         __gu_err;                                                       \
 249 })
 250
 251 #define __get_user_nosleep(x, ptr, size)                        \
 252 ({                                                              \
 253         long __gu_err;                                          \
 254         unsigned long __gu_val;                                 \
 255         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 256         __chk_user_ptr(ptr);                                    \
 257         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 258         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 259         __gu_err;                                               \
 260 })
 261
 262
 263 /* more complex routines */
 264
 265 extern unsigned long __copy_tofrom_user(void __user *to,
 266                 const void __user *from, unsigned long size);
 267
 268 #ifdef __powerpc64__
 269 static inline unsigned long
 270 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 271 {
 272         return __copy_tofrom_user(to, from, n);
 273 }
 274 #endif /* __powerpc64__ */
 275
 276 static inline unsigned long raw_copy_from_user(void *to,
 277                 const void __user *from, unsigned long n)
 278 {
 279         if (__builtin_constant_p(n) && (n <= 8)) {
 280                 unsigned long ret = 1;
 281
 282                 switch (n) {
 283                 case 1:
 284                         __get_user_size(*(u8 *)to, from, 1, ret);
 285                         break;
 286                 case 2:
 287                         __get_user_size(*(u16 *)to, from, 2, ret);
 288                         break;
 289                 case 4:
 290                         __get_user_size(*(u32 *)to, from, 4, ret);
 291                         break;
 292                 case 8:
 293                         __get_user_size(*(u64 *)to, from, 8, ret);
 294                         break;
 295                 }
 296                 if (ret == 0)
 297                         return 0;
 298         }
 299
 300         return __copy_tofrom_user((__force void __user *)to, from, n);
 301 }
 302
 303 static inline unsigned long raw_copy_to_user(void __user *to,
 304                 const void *from, unsigned long n)
 305 {
 306         if (__builtin_constant_p(n) && (n <= 8)) {
 307                 unsigned long ret = 1;
 308
 309                 switch (n) {
 310                 case 1:
 311                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 312                         break;
 313                 case 2:
 314                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 315                         break;
 316                 case 4:
 317                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 318                         break;
 319                 case 8:
 320                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 321                         break;
 322                 }
 323                 if (ret == 0)
 324                         return 0;
 325         }
 326
 327         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 328 }
 329
 330 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 331
 332 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 333 {
 334         might_fault();
 335         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 336                 return __clear_user(addr, size);
 337         return size;
 338 }
 339
 340 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 341 extern __must_check long strnlen_user(const char __user *str, long n);
 342
 343 #endif  /* _ARCH_POWERPC_UACCESS_H */