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 static inline int __access_ok(unsigned long addr, unsigned long size,
  51                         mm_segment_t seg)
  52 {
  53         if (addr > seg.seg)
  54                 return 0;
  55         return (size == 0 || size - 1 <= seg.seg - addr);
  56 }
  57
  58 #endif
  59
  60 #define access_ok(type, addr, size)             \
  61         (__chk_user_ptr(addr),                  \
  62          __access_ok((__force unsigned long)(addr), (size), get_fs()))
  63
  64 /*
  65  * These are the main single-value transfer routines.  They automatically
  66  * use the right size if we just have the right pointer type.
  67  *
  68  * This gets kind of ugly. We want to return _two_ values in "get_user()"
  69  * and yet we don't want to do any pointers, because that is too much
  70  * of a performance impact. Thus we have a few rather ugly macros here,
  71  * and hide all the ugliness from the user.
  72  *
  73  * The "__xxx" versions of the user access functions are versions that
  74  * do not verify the address space, that must have been done previously
  75  * with a separate "access_ok()" call (this is used when we do multiple
  76  * accesses to the same area of user memory).
  77  *
  78  * As we use the same address space for kernel and user data on the
  79  * PowerPC, we can just do these as direct assignments.  (Of course, the
  80  * exception handling means that it's no longer "just"...)
  81  *
  82  */
  83 #define get_user(x, ptr) \
  84         __get_user_check((x), (ptr), sizeof(*(ptr)))
  85 #define put_user(x, ptr) \
  86         __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  87
  88 #define __get_user(x, ptr) \
  89         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  90 #define __put_user(x, ptr) \
  91         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  92
  93 #define __get_user_inatomic(x, ptr) \
  94         __get_user_nosleep((x), (ptr), sizeof(*(ptr)))
  95 #define __put_user_inatomic(x, ptr) \
  96         __put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  97
  98 extern long __put_user_bad(void);
  99
 100 /*
 101  * We don't tell gcc that we are accessing memory, but this is OK
 102  * because we do not write to any memory gcc knows about, so there
 103  * are no aliasing issues.
 104  */
 105 #define __put_user_asm(x, addr, err, op)                        \
 106         __asm__ __volatile__(                                   \
 107                 "1:     " op " %1,0(%2) # put_user\n"           \
 108                 "2:\n"                                          \
 109                 ".section .fixup,\"ax\"\n"                      \
 110                 "3:     li %0,%3\n"                             \
 111                 "       b 2b\n"                                 \
 112                 ".previous\n"                                   \
 113                 EX_TABLE(1b, 3b)                                \
 114                 : "=r" (err)                                    \
 115                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 116
 117 #ifdef __powerpc64__
 118 #define __put_user_asm2(x, ptr, retval)                         \
 119           __put_user_asm(x, ptr, retval, "std")
 120 #else /* __powerpc64__ */
 121 #define __put_user_asm2(x, addr, err)                           \
 122         __asm__ __volatile__(                                   \
 123                 "1:     stw %1,0(%2)\n"                         \
 124                 "2:     stw %1+1,4(%2)\n"                       \
 125                 "3:\n"                                          \
 126                 ".section .fixup,\"ax\"\n"                      \
 127                 "4:     li %0,%3\n"                             \
 128                 "       b 3b\n"                                 \
 129                 ".previous\n"                                   \
 130                 EX_TABLE(1b, 4b)                                \
 131                 EX_TABLE(2b, 4b)                                \
 132                 : "=r" (err)                                    \
 133                 : "r" (x), "b" (addr), "i" (-EFAULT), "0" (err))
 134 #endif /* __powerpc64__ */
 135
 136 #define __put_user_size(x, ptr, size, retval)                   \
 137 do {                                                            \
 138         retval = 0;                                             \
 139         switch (size) {                                         \
 140           case 1: __put_user_asm(x, ptr, retval, "stb"); break; \
 141           case 2: __put_user_asm(x, ptr, retval, "sth"); break; \
 142           case 4: __put_user_asm(x, ptr, retval, "stw"); break; \
 143           case 8: __put_user_asm2(x, ptr, retval); break;       \
 144           default: __put_user_bad();                            \
 145         }                                                       \
 146 } while (0)
 147
 148 #define __put_user_nocheck(x, ptr, size)                        \
 149 ({                                                              \
 150         long __pu_err;                                          \
 151         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 152         if (!is_kernel_addr((unsigned long)__pu_addr))          \
 153                 might_fault();                                  \
 154         __chk_user_ptr(ptr);                                    \
 155         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 156         __pu_err;                                               \
 157 })
 158
 159 #define __put_user_check(x, ptr, size)                                  \
 160 ({                                                                      \
 161         long __pu_err = -EFAULT;                                        \
 162         __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 163         might_fault();                                                  \
 164         if (access_ok(VERIFY_WRITE, __pu_addr, size))                   \
 165                 __put_user_size((x), __pu_addr, (size), __pu_err);      \
 166         __pu_err;                                                       \
 167 })
 168
 169 #define __put_user_nosleep(x, ptr, size)                        \
 170 ({                                                              \
 171         long __pu_err;                                          \
 172         __typeof__(*(ptr)) __user *__pu_addr = (ptr);           \
 173         __chk_user_ptr(ptr);                                    \
 174         __put_user_size((x), __pu_addr, (size), __pu_err);      \
 175         __pu_err;                                               \
 176 })
 177
 178
 179 extern long __get_user_bad(void);
 180
 181 /*
 182  * This does an atomic 128 byte aligned load from userspace.
 183  * Upto caller to do enable_kernel_vmx() before calling!
 184  */
 185 #define __get_user_atomic_128_aligned(kaddr, uaddr, err)                \
 186         __asm__ __volatile__(                           \
 187                 "1:     lvx  0,0,%1     # get user\n"   \
 188                 "       stvx 0,0,%2     # put kernel\n" \
 189                 "2:\n"                                  \
 190                 ".section .fixup,\"ax\"\n"              \
 191                 "3:     li %0,%3\n"                     \
 192                 "       b 2b\n"                         \
 193                 ".previous\n"                           \
 194                 EX_TABLE(1b, 3b)                        \
 195                 : "=r" (err)                    \
 196                 : "b" (uaddr), "b" (kaddr), "i" (-EFAULT), "0" (err))
 197
 198 #define __get_user_asm(x, addr, err, op)                \
 199         __asm__ __volatile__(                           \
 200                 "1:     "op" %1,0(%2)   # get_user\n"   \
 201                 "2:\n"                                  \
 202                 ".section .fixup,\"ax\"\n"              \
 203                 "3:     li %0,%3\n"                     \
 204                 "       li %1,0\n"                      \
 205                 "       b 2b\n"                         \
 206                 ".previous\n"                           \
 207                 EX_TABLE(1b, 3b)                        \
 208                 : "=r" (err), "=r" (x)                  \
 209                 : "b" (addr), "i" (-EFAULT), "0" (err))
 210
 211 #ifdef __powerpc64__
 212 #define __get_user_asm2(x, addr, err)                   \
 213         __get_user_asm(x, addr, err, "ld")
 214 #else /* __powerpc64__ */
 215 #define __get_user_asm2(x, addr, err)                   \
 216         __asm__ __volatile__(                           \
 217                 "1:     lwz %1,0(%2)\n"                 \
 218                 "2:     lwz %1+1,4(%2)\n"               \
 219                 "3:\n"                                  \
 220                 ".section .fixup,\"ax\"\n"              \
 221                 "4:     li %0,%3\n"                     \
 222                 "       li %1,0\n"                      \
 223                 "       li %1+1,0\n"                    \
 224                 "       b 3b\n"                         \
 225                 ".previous\n"                           \
 226                 EX_TABLE(1b, 4b)                        \
 227                 EX_TABLE(2b, 4b)                        \
 228                 : "=r" (err), "=&r" (x)                 \
 229                 : "b" (addr), "i" (-EFAULT), "0" (err))
 230 #endif /* __powerpc64__ */
 231
 232 #define __get_user_size(x, ptr, size, retval)                   \
 233 do {                                                            \
 234         retval = 0;                                             \
 235         __chk_user_ptr(ptr);                                    \
 236         if (size > sizeof(x))                                   \
 237                 (x) = __get_user_bad();                         \
 238         switch (size) {                                         \
 239         case 1: __get_user_asm(x, ptr, retval, "lbz"); break;   \
 240         case 2: __get_user_asm(x, ptr, retval, "lhz"); break;   \
 241         case 4: __get_user_asm(x, ptr, retval, "lwz"); break;   \
 242         case 8: __get_user_asm2(x, ptr, retval);  break;        \
 243         default: (x) = __get_user_bad();                        \
 244         }                                                       \
 245 } while (0)
 246
 247 #define __get_user_nocheck(x, ptr, size)                        \
 248 ({                                                              \
 249         long __gu_err;                                          \
 250         unsigned long __gu_val;                                 \
 251         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 252         __chk_user_ptr(ptr);                                    \
 253         if (!is_kernel_addr((unsigned long)__gu_addr))          \
 254                 might_fault();                                  \
 255         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 256         (x) = (__typeof__(*(ptr)))__gu_val;                     \
 257         __gu_err;                                               \
 258 })
 259
 260 #define __get_user_check(x, ptr, size)                                  \
 261 ({                                                                      \
 262         long __gu_err = -EFAULT;                                        \
 263         unsigned long  __gu_val = 0;                                    \
 264         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 265         might_fault();                                                  \
 266         if (access_ok(VERIFY_READ, __gu_addr, (size)))                  \
 267                 __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 268         (x) = (__force __typeof__(*(ptr)))__gu_val;                             \
 269         __gu_err;                                                       \
 270 })
 271
 272 #define __get_user_nosleep(x, ptr, size)                        \
 273 ({                                                              \
 274         long __gu_err;                                          \
 275         unsigned long __gu_val;                                 \
 276         const __typeof__(*(ptr)) __user *__gu_addr = (ptr);     \
 277         __chk_user_ptr(ptr);                                    \
 278         __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 279         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 280         __gu_err;                                               \
 281 })
 282
 283
 284 /* more complex routines */
 285
 286 extern unsigned long __copy_tofrom_user(void __user *to,
 287                 const void __user *from, unsigned long size);
 288
 289 #ifdef __powerpc64__
 290 static inline unsigned long
 291 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n)
 292 {
 293         return __copy_tofrom_user(to, from, n);
 294 }
 295 #endif /* __powerpc64__ */
 296
 297 static inline unsigned long raw_copy_from_user(void *to,
 298                 const void __user *from, unsigned long n)
 299 {
 300         if (__builtin_constant_p(n) && (n <= 8)) {
 301                 unsigned long ret = 1;
 302
 303                 switch (n) {
 304                 case 1:
 305                         __get_user_size(*(u8 *)to, from, 1, ret);
 306                         break;
 307                 case 2:
 308                         __get_user_size(*(u16 *)to, from, 2, ret);
 309                         break;
 310                 case 4:
 311                         __get_user_size(*(u32 *)to, from, 4, ret);
 312                         break;
 313                 case 8:
 314                         __get_user_size(*(u64 *)to, from, 8, ret);
 315                         break;
 316                 }
 317                 if (ret == 0)
 318                         return 0;
 319         }
 320
 321         return __copy_tofrom_user((__force void __user *)to, from, n);
 322 }
 323
 324 static inline unsigned long raw_copy_to_user(void __user *to,
 325                 const void *from, unsigned long n)
 326 {
 327         if (__builtin_constant_p(n) && (n <= 8)) {
 328                 unsigned long ret = 1;
 329
 330                 switch (n) {
 331                 case 1:
 332                         __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret);
 333                         break;
 334                 case 2:
 335                         __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret);
 336                         break;
 337                 case 4:
 338                         __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret);
 339                         break;
 340                 case 8:
 341                         __put_user_size(*(u64 *)from, (u64 __user *)to, 8, ret);
 342                         break;
 343                 }
 344                 if (ret == 0)
 345                         return 0;
 346         }
 347
 348         return __copy_tofrom_user(to, (__force const void __user *)from, n);
 349 }
 350
 351 extern unsigned long __clear_user(void __user *addr, unsigned long size);
 352
 353 static inline unsigned long clear_user(void __user *addr, unsigned long size)
 354 {
 355         might_fault();
 356         if (likely(access_ok(VERIFY_WRITE, addr, size)))
 357                 return __clear_user(addr, size);
 358         return size;
 359 }
 360
 361 extern long strncpy_from_user(char *dst, const char __user *src, long count);
 362 extern __must_check long strnlen_user(const char __user *str, long n);
 363
 364 extern long __copy_from_user_flushcache(void *dst, const void __user *src,
 365                 unsigned size);
 366 extern void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
 367                            size_t len);
 368
 369 #endif  /* _ARCH_POWERPC_UACCESS_H */