arch/s390/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  *  S390 version
   4  *    Copyright IBM Corp. 1999, 2000
   5  *    Author(s): Hartmut Penner (hp@de.ibm.com),
   6  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   7  *
   8  *  Derived from "include/asm-i386/uaccess.h"
   9  */
  10 #ifndef __S390_UACCESS_H
  11 #define __S390_UACCESS_H
  12
  13 /*
  14  * User space memory access functions
  15  */
  16 #include <asm/processor.h>
  17 #include <asm/ctl_reg.h>
  18 #include <asm/extable.h>
  19
  20
  21 /*
  22  * The fs value determines whether argument validity checking should be
  23  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  24  * get_fs() == KERNEL_DS, checking is bypassed.
  25  *
  26  * For historical reasons, these macros are grossly misnamed.
  27  */
  28
  29 #define MAKE_MM_SEG(a)  ((mm_segment_t) { (a) })
  30
  31
  32 #define KERNEL_DS       MAKE_MM_SEG(0)
  33 #define USER_DS         MAKE_MM_SEG(1)
  34
  35 #define get_ds()        (KERNEL_DS)
  36 #define get_fs()        (current->thread.mm_segment)
  37 #define segment_eq(a,b) ((a).ar4 == (b).ar4)
  38
  39 static inline void set_fs(mm_segment_t fs)
  40 {
  41         current->thread.mm_segment = fs;
  42         if (uaccess_kernel()) {
  43                 set_cpu_flag(CIF_ASCE_SECONDARY);
  44                 __ctl_load(S390_lowcore.kernel_asce, 7, 7);
  45         } else {
  46                 clear_cpu_flag(CIF_ASCE_SECONDARY);
  47                 __ctl_load(S390_lowcore.user_asce, 7, 7);
  48         }
  49 }
  50
  51 static inline int __range_ok(unsigned long addr, unsigned long size)
  52 {
  53         return 1;
  54 }
  55
  56 #define __access_ok(addr, size)                         \
  57 ({                                                      \
  58         __chk_user_ptr(addr);                           \
  59         __range_ok((unsigned long)(addr), (size));      \
  60 })
  61
  62 #define access_ok(type, addr, size) __access_ok(addr, size)
  63
  64 unsigned long __must_check
  65 raw_copy_from_user(void *to, const void __user *from, unsigned long n);
  66
  67 unsigned long __must_check
  68 raw_copy_to_user(void __user *to, const void *from, unsigned long n);
  69
  70 #define INLINE_COPY_FROM_USER
  71 #define INLINE_COPY_TO_USER
  72
  73 #ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
  74
  75 #define __put_get_user_asm(to, from, size, spec)                \
  76 ({                                                              \
  77         register unsigned long __reg0 asm("0") = spec;          \
  78         int __rc;                                               \
  79                                                                 \
  80         asm volatile(                                           \
  81                 "0:     mvcos   %1,%3,%2\n"                     \
  82                 "1:     xr      %0,%0\n"                        \
  83                 "2:\n"                                          \
  84                 ".pushsection .fixup, \"ax\"\n"                 \
  85                 "3:     lhi     %0,%5\n"                        \
  86                 "       jg      2b\n"                           \
  87                 ".popsection\n"                                 \
  88                 EX_TABLE(0b,3b) EX_TABLE(1b,3b)                 \
  89                 : "=d" (__rc), "+Q" (*(to))                     \
  90                 : "d" (size), "Q" (*(from)),                    \
  91                   "d" (__reg0), "K" (-EFAULT)                   \
  92                 : "cc");                                        \
  93         __rc;                                                   \
  94 })
  95
  96 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
  97 {
  98         unsigned long spec = 0x810000UL;
  99         int rc;
 100
 101         switch (size) {
 102         case 1:
 103                 rc = __put_get_user_asm((unsigned char __user *)ptr,
 104                                         (unsigned char *)x,
 105                                         size, spec);
 106                 break;
 107         case 2:
 108                 rc = __put_get_user_asm((unsigned short __user *)ptr,
 109                                         (unsigned short *)x,
 110                                         size, spec);
 111                 break;
 112         case 4:
 113                 rc = __put_get_user_asm((unsigned int __user *)ptr,
 114                                         (unsigned int *)x,
 115                                         size, spec);
 116                 break;
 117         case 8:
 118                 rc = __put_get_user_asm((unsigned long __user *)ptr,
 119                                         (unsigned long *)x,
 120                                         size, spec);
 121                 break;
 122         }
 123         return rc;
 124 }
 125
 126 static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
 127 {
 128         unsigned long spec = 0x81UL;
 129         int rc;
 130
 131         switch (size) {
 132         case 1:
 133                 rc = __put_get_user_asm((unsigned char *)x,
 134                                         (unsigned char __user *)ptr,
 135                                         size, spec);
 136                 break;
 137         case 2:
 138                 rc = __put_get_user_asm((unsigned short *)x,
 139                                         (unsigned short __user *)ptr,
 140                                         size, spec);
 141                 break;
 142         case 4:
 143                 rc = __put_get_user_asm((unsigned int *)x,
 144                                         (unsigned int __user *)ptr,
 145                                         size, spec);
 146                 break;
 147         case 8:
 148                 rc = __put_get_user_asm((unsigned long *)x,
 149                                         (unsigned long __user *)ptr,
 150                                         size, spec);
 151                 break;
 152         }
 153         return rc;
 154 }
 155
 156 #else /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 157
 158 static inline int __put_user_fn(void *x, void __user *ptr, unsigned long size)
 159 {
 160         size = raw_copy_to_user(ptr, x, size);
 161         return size ? -EFAULT : 0;
 162 }
 163
 164 static inline int __get_user_fn(void *x, const void __user *ptr, unsigned long size)
 165 {
 166         size = raw_copy_from_user(x, ptr, size);
 167         return size ? -EFAULT : 0;
 168 }
 169
 170 #endif /* CONFIG_HAVE_MARCH_Z10_FEATURES */
 171
 172 /*
 173  * These are the main single-value transfer routines.  They automatically
 174  * use the right size if we just have the right pointer type.
 175  */
 176 #define __put_user(x, ptr) \
 177 ({                                                              \
 178         __typeof__(*(ptr)) __x = (x);                           \
 179         int __pu_err = -EFAULT;                                 \
 180         __chk_user_ptr(ptr);                                    \
 181         switch (sizeof (*(ptr))) {                              \
 182         case 1:                                                 \
 183         case 2:                                                 \
 184         case 4:                                                 \
 185         case 8:                                                 \
 186                 __pu_err = __put_user_fn(&__x, ptr,             \
 187                                          sizeof(*(ptr)));       \
 188                 break;                                          \
 189         default:                                                \
 190                 __put_user_bad();                               \
 191                 break;                                          \
 192          }                                                      \
 193         __builtin_expect(__pu_err, 0);                          \
 194 })
 195
 196 #define put_user(x, ptr)                                        \
 197 ({                                                              \
 198         might_fault();                                          \
 199         __put_user(x, ptr);                                     \
 200 })
 201
 202
 203 int __put_user_bad(void) __attribute__((noreturn));
 204
 205 #define __get_user(x, ptr)                                      \
 206 ({                                                              \
 207         int __gu_err = -EFAULT;                                 \
 208         __chk_user_ptr(ptr);                                    \
 209         switch (sizeof(*(ptr))) {                               \
 210         case 1: {                                               \
 211                 unsigned char __x = 0;                          \
 212                 __gu_err = __get_user_fn(&__x, ptr,             \
 213                                          sizeof(*(ptr)));       \
 214                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 215                 break;                                          \
 216         };                                                      \
 217         case 2: {                                               \
 218                 unsigned short __x = 0;                         \
 219                 __gu_err = __get_user_fn(&__x, ptr,             \
 220                                          sizeof(*(ptr)));       \
 221                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 222                 break;                                          \
 223         };                                                      \
 224         case 4: {                                               \
 225                 unsigned int __x = 0;                           \
 226                 __gu_err = __get_user_fn(&__x, ptr,             \
 227                                          sizeof(*(ptr)));       \
 228                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 229                 break;                                          \
 230         };                                                      \
 231         case 8: {                                               \
 232                 unsigned long long __x = 0;                     \
 233                 __gu_err = __get_user_fn(&__x, ptr,             \
 234                                          sizeof(*(ptr)));       \
 235                 (x) = *(__force __typeof__(*(ptr)) *) &__x;     \
 236                 break;                                          \
 237         };                                                      \
 238         default:                                                \
 239                 __get_user_bad();                               \
 240                 break;                                          \
 241         }                                                       \
 242         __builtin_expect(__gu_err, 0);                          \
 243 })
 244
 245 #define get_user(x, ptr)                                        \
 246 ({                                                              \
 247         might_fault();                                          \
 248         __get_user(x, ptr);                                     \
 249 })
 250
 251 int __get_user_bad(void) __attribute__((noreturn));
 252
 253 unsigned long __must_check
 254 raw_copy_in_user(void __user *to, const void __user *from, unsigned long n);
 255
 256 /*
 257  * Copy a null terminated string from userspace.
 258  */
 259
 260 long __strncpy_from_user(char *dst, const char __user *src, long count);
 261
 262 static inline long __must_check
 263 strncpy_from_user(char *dst, const char __user *src, long count)
 264 {
 265         might_fault();
 266         return __strncpy_from_user(dst, src, count);
 267 }
 268
 269 unsigned long __must_check __strnlen_user(const char __user *src, unsigned long count);
 270
 271 static inline unsigned long strnlen_user(const char __user *src, unsigned long n)
 272 {
 273         might_fault();
 274         return __strnlen_user(src, n);
 275 }
 276
 277 /*
 278  * Zero Userspace
 279  */
 280 unsigned long __must_check __clear_user(void __user *to, unsigned long size);
 281
 282 static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
 283 {
 284         might_fault();
 285         return __clear_user(to, n);
 286 }
 287
 288 int copy_to_user_real(void __user *dest, void *src, unsigned long count);
 289 void s390_kernel_write(void *dst, const void *src, size_t size);
 290
 291 #endif /* __S390_UACCESS_H */