LXR linux/arch/openrisc/include/asm/uaccess.h

   1/* SPDX-License-Identifier: GPL-2.0-or-later */
   2/*
   3 * OpenRISC Linux
   4 *
   5 * Linux architectural port borrowing liberally from similar works of
   6 * others.  All original copyrights apply as per the original source
   7 * declaration.
   8 *
   9 * OpenRISC implementation:
  10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
  11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
  12 * et al.
  13 */
  14
  15#ifndef __ASM_OPENRISC_UACCESS_H
  16#define __ASM_OPENRISC_UACCESS_H
  17
  18/*
  19 * User space memory access functions
  20 */
  21#include <linux/prefetch.h>
  22#include <linux/string.h>
  23#include <asm/page.h>
  24#include <asm/extable.h>
  25
  26/*
  27 * The fs value determines whether argument validity checking should be
  28 * performed or not.  If get_fs() == USER_DS, checking is performed, with
  29 * get_fs() == KERNEL_DS, checking is bypassed.
  30 *
  31 * For historical reasons, these macros are grossly misnamed.
  32 */
  33
  34/* addr_limit is the maximum accessible address for the task. we misuse
  35 * the KERNEL_DS and USER_DS values to both assign and compare the
  36 * addr_limit values through the equally misnamed get/set_fs macros.
  37 * (see above)
  38 */
  39
  40#define KERNEL_DS       (~0UL)
  41
  42#define USER_DS         (TASK_SIZE)
  43#define get_fs()        (current_thread_info()->addr_limit)
  44#define set_fs(x)       (current_thread_info()->addr_limit = (x))
  45
  46#define uaccess_kernel()        (get_fs() == KERNEL_DS)
  47
  48/* Ensure that the range from addr to addr+size is all within the process'
  49 * address space
  50 */
  51static inline int __range_ok(unsigned long addr, unsigned long size)
  52{
  53        const mm_segment_t fs = get_fs();
  54
  55        return size <= fs && addr <= (fs - size);
  56}
  57
  58#define access_ok(addr, size)                                           \
  59({                                                                      \
  60        __chk_user_ptr(addr);                                           \
  61        __range_ok((unsigned long)(addr), (size));                      \
  62})
  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 uglyness 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#define get_user(x, ptr) \
  83        __get_user_check((x), (ptr), sizeof(*(ptr)))
  84#define put_user(x, ptr) \
  85        __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  86
  87#define __get_user(x, ptr) \
  88        __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  89#define __put_user(x, ptr) \
  90        __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  91
  92extern long __put_user_bad(void);
  93
  94#define __put_user_nocheck(x, ptr, size)                \
  95({                                                      \
  96        long __pu_err;                                  \
  97        __put_user_size((x), (ptr), (size), __pu_err);  \
  98        __pu_err;                                       \
  99})
 100
 101#define __put_user_check(x, ptr, size)                                  \
 102({                                                                      \
 103        long __pu_err = -EFAULT;                                        \
 104        __typeof__(*(ptr)) __user *__pu_addr = (ptr);                   \
 105        if (access_ok(__pu_addr, size))                 \
 106                __put_user_size((x), __pu_addr, (size), __pu_err);      \
 107        __pu_err;                                                       \
 108})
 109
 110#define __put_user_size(x, ptr, size, retval)                           \
 111do {                                                                    \
 112        retval = 0;                                                     \
 113        switch (size) {                                                 \
 114        case 1: __put_user_asm(x, ptr, retval, "l.sb"); break;          \
 115        case 2: __put_user_asm(x, ptr, retval, "l.sh"); break;          \
 116        case 4: __put_user_asm(x, ptr, retval, "l.sw"); break;          \
 117        case 8: __put_user_asm2(x, ptr, retval); break;                 \
 118        default: __put_user_bad();                                      \
 119        }                                                               \
 120} while (0)
 121
 122struct __large_struct {
 123        unsigned long buf[100];
 124};
 125#define __m(x) (*(struct __large_struct *)(x))
 126
 127/*
 128 * We don't tell gcc that we are accessing memory, but this is OK
 129 * because we do not write to any memory gcc knows about, so there
 130 * are no aliasing issues.
 131 */
 132#define __put_user_asm(x, addr, err, op)                        \
 133        __asm__ __volatile__(                                   \
 134                "1:     "op" 0(%2),%1\n"                        \
 135                "2:\n"                                          \
 136                ".section .fixup,\"ax\"\n"                      \
 137                "3:     l.addi %0,r0,%3\n"                      \
 138                "       l.j 2b\n"                               \
 139                "       l.nop\n"                                \
 140                ".previous\n"                                   \
 141                ".section __ex_table,\"a\"\n"                   \
 142                "       .align 2\n"                             \
 143                "       .long 1b,3b\n"                          \
 144                ".previous"                                     \
 145                : "=r"(err)                                     \
 146                : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 147
 148#define __put_user_asm2(x, addr, err)                           \
 149        __asm__ __volatile__(                                   \
 150                "1:     l.sw 0(%2),%1\n"                        \
 151                "2:     l.sw 4(%2),%H1\n"                       \
 152                "3:\n"                                          \
 153                ".section .fixup,\"ax\"\n"                      \
 154                "4:     l.addi %0,r0,%3\n"                      \
 155                "       l.j 3b\n"                               \
 156                "       l.nop\n"                                \
 157                ".previous\n"                                   \
 158                ".section __ex_table,\"a\"\n"                   \
 159                "       .align 2\n"                             \
 160                "       .long 1b,4b\n"                          \
 161                "       .long 2b,4b\n"                          \
 162                ".previous"                                     \
 163                : "=r"(err)                                     \
 164                : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 165
 166#define __get_user_nocheck(x, ptr, size)                        \
 167({                                                              \
 168        long __gu_err;                                          \
 169        __get_user_size((x), (ptr), (size), __gu_err);          \
 170        __gu_err;                                               \
 171})
 172
 173#define __get_user_check(x, ptr, size)                                  \
 174({                                                                      \
 175        long __gu_err = -EFAULT;                                        \
 176        const __typeof__(*(ptr)) __user *__gu_addr = (ptr);             \
 177        if (access_ok(__gu_addr, size))                                 \
 178                __get_user_size((x), __gu_addr, (size), __gu_err);      \
 179        else                                                            \
 180                (x) = (__typeof__(*(ptr))) 0;                           \
 181        __gu_err;                                                       \
 182})
 183
 184extern long __get_user_bad(void);
 185
 186#define __get_user_size(x, ptr, size, retval)                           \
 187do {                                                                    \
 188        retval = 0;                                                     \
 189        switch (size) {                                                 \
 190        case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break;         \
 191        case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break;         \
 192        case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break;         \
 193        case 8: __get_user_asm2(x, ptr, retval); break;                 \
 194        default: (x) = (__typeof__(*(ptr)))__get_user_bad();            \
 195        }                                                               \
 196} while (0)
 197
 198#define __get_user_asm(x, addr, err, op)                \
 199{                                                       \
 200        unsigned long __gu_tmp;                         \
 201        __asm__ __volatile__(                           \
 202                "1:     "op" %1,0(%2)\n"                \
 203                "2:\n"                                  \
 204                ".section .fixup,\"ax\"\n"              \
 205                "3:     l.addi %0,r0,%3\n"              \
 206                "       l.addi %1,r0,0\n"               \
 207                "       l.j 2b\n"                       \
 208                "       l.nop\n"                        \
 209                ".previous\n"                           \
 210                ".section __ex_table,\"a\"\n"           \
 211                "       .align 2\n"                     \
 212                "       .long 1b,3b\n"                  \
 213                ".previous"                             \
 214                : "=r"(err), "=r"(__gu_tmp)             \
 215                : "r"(addr), "i"(-EFAULT), "0"(err));   \
 216        (x) = (__typeof__(*(addr)))__gu_tmp;            \
 217}
 218
 219#define __get_user_asm2(x, addr, err)                   \
 220{                                                       \
 221        unsigned long long __gu_tmp;                    \
 222        __asm__ __volatile__(                           \
 223                "1:     l.lwz %1,0(%2)\n"               \
 224                "2:     l.lwz %H1,4(%2)\n"              \
 225                "3:\n"                                  \
 226                ".section .fixup,\"ax\"\n"              \
 227                "4:     l.addi %0,r0,%3\n"              \
 228                "       l.addi %1,r0,0\n"               \
 229                "       l.addi %H1,r0,0\n"              \
 230                "       l.j 3b\n"                       \
 231                "       l.nop\n"                        \
 232                ".previous\n"                           \
 233                ".section __ex_table,\"a\"\n"           \
 234                "       .align 2\n"                     \
 235                "       .long 1b,4b\n"                  \
 236                "       .long 2b,4b\n"                  \
 237                ".previous"                             \
 238                : "=r"(err), "=&r"(__gu_tmp)            \
 239                : "r"(addr), "i"(-EFAULT), "0"(err));   \
 240        (x) = (__typeof__(*(addr)))(                    \
 241                (__typeof__((x)-(x)))__gu_tmp);         \
 242}
 243
 244/* more complex routines */
 245
 246extern unsigned long __must_check
 247__copy_tofrom_user(void *to, const void *from, unsigned long size);
 248static inline unsigned long
 249raw_copy_from_user(void *to, const void __user *from, unsigned long size)
 250{
 251        return __copy_tofrom_user(to, (__force const void *)from, size);
 252}
 253static inline unsigned long
 254raw_copy_to_user(void __user *to, const void *from, unsigned long size)
 255{
 256        return __copy_tofrom_user((__force void *)to, from, size);
 257}
 258#define INLINE_COPY_FROM_USER
 259#define INLINE_COPY_TO_USER
 260
 261extern unsigned long __clear_user(void __user *addr, unsigned long size);
 262
 263static inline __must_check unsigned long
 264clear_user(void __user *addr, unsigned long size)
 265{
 266        if (likely(access_ok(addr, size)))
 267                size = __clear_user(addr, size);
 268        return size;
 269}
 270
 271#define user_addr_max() \
 272        (uaccess_kernel() ? ~0UL : TASK_SIZE)
 273
 274extern long strncpy_from_user(char *dest, const char __user *src, long count);
 275
 276extern __must_check long strnlen_user(const char __user *str, long n);
 277
 278#endif /* __ASM_OPENRISC_UACCESS_H */
 279