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 segment_eq(a, b)        ((a) == (b))
  47
  48/* Ensure that the range from addr to addr+size is all within the process'
  49 * address space
  50 */
  51#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))
  52
  53/* Ensure that addr is below task's addr_limit */
  54#define __addr_ok(addr) ((unsigned long) addr < get_fs())
  55
  56#define access_ok(addr, size)                                           \
  57({                                                                      \
  58        unsigned long __ao_addr = (unsigned long)(addr);                \
  59        unsigned long __ao_size = (unsigned long)(size);                \
  60        __range_ok(__ao_addr, __ao_size);                               \
  61})
  62
  63/*
  64 * These are the main single-value transfer routines.  They automatically
  65 * use the right size if we just have the right pointer type.
  66 *
  67 * This gets kind of ugly. We want to return _two_ values in "get_user()"
  68 * and yet we don't want to do any pointers, because that is too much
  69 * of a performance impact. Thus we have a few rather ugly macros here,
  70 * and hide all the uglyness from the user.
  71 *
  72 * The "__xxx" versions of the user access functions are versions that
  73 * do not verify the address space, that must have been done previously
  74 * with a separate "access_ok()" call (this is used when we do multiple
  75 * accesses to the same area of user memory).
  76 *
  77 * As we use the same address space for kernel and user data on the
  78 * PowerPC, we can just do these as direct assignments.  (Of course, the
  79 * exception handling means that it's no longer "just"...)
  80 */
  81#define get_user(x, ptr) \
  82        __get_user_check((x), (ptr), sizeof(*(ptr)))
  83#define put_user(x, ptr) \
  84        __put_user_check((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  85
  86#define __get_user(x, ptr) \
  87        __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
  88#define __put_user(x, ptr) \
  89        __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  90
  91extern long __put_user_bad(void);
  92
  93#define __put_user_nocheck(x, ptr, size)                \
  94({                                                      \
  95        long __pu_err;                                  \
  96        __put_user_size((x), (ptr), (size), __pu_err);  \
  97        __pu_err;                                       \
  98})
  99
 100#define __put_user_check(x, ptr, size)                                  \
 101({                                                                      \
 102        long __pu_err = -EFAULT;                                        \
 103        __typeof__(*(ptr)) *__pu_addr = (ptr);                          \
 104        if (access_ok(__pu_addr, size))                 \
 105                __put_user_size((x), __pu_addr, (size), __pu_err);      \
 106        __pu_err;                                                       \
 107})
 108
 109#define __put_user_size(x, ptr, size, retval)                           \
 110do {                                                                    \
 111        retval = 0;                                                     \
 112        switch (size) {                                                 \
 113        case 1: __put_user_asm(x, ptr, retval, "l.sb"); break;          \
 114        case 2: __put_user_asm(x, ptr, retval, "l.sh"); break;          \
 115        case 4: __put_user_asm(x, ptr, retval, "l.sw"); break;          \
 116        case 8: __put_user_asm2(x, ptr, retval); break;                 \
 117        default: __put_user_bad();                                      \
 118        }                                                               \
 119} while (0)
 120
 121struct __large_struct {
 122        unsigned long buf[100];
 123};
 124#define __m(x) (*(struct __large_struct *)(x))
 125
 126/*
 127 * We don't tell gcc that we are accessing memory, but this is OK
 128 * because we do not write to any memory gcc knows about, so there
 129 * are no aliasing issues.
 130 */
 131#define __put_user_asm(x, addr, err, op)                        \
 132        __asm__ __volatile__(                                   \
 133                "1:     "op" 0(%2),%1\n"                        \
 134                "2:\n"                                          \
 135                ".section .fixup,\"ax\"\n"                      \
 136                "3:     l.addi %0,r0,%3\n"                      \
 137                "       l.j 2b\n"                               \
 138                "       l.nop\n"                                \
 139                ".previous\n"                                   \
 140                ".section __ex_table,\"a\"\n"                   \
 141                "       .align 2\n"                             \
 142                "       .long 1b,3b\n"                          \
 143                ".previous"                                     \
 144                : "=r"(err)                                     \
 145                : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 146
 147#define __put_user_asm2(x, addr, err)                           \
 148        __asm__ __volatile__(                                   \
 149                "1:     l.sw 0(%2),%1\n"                        \
 150                "2:     l.sw 4(%2),%H1\n"                       \
 151                "3:\n"                                          \
 152                ".section .fixup,\"ax\"\n"                      \
 153                "4:     l.addi %0,r0,%3\n"                      \
 154                "       l.j 3b\n"                               \
 155                "       l.nop\n"                                \
 156                ".previous\n"                                   \
 157                ".section __ex_table,\"a\"\n"                   \
 158                "       .align 2\n"                             \
 159                "       .long 1b,4b\n"                          \
 160                "       .long 2b,4b\n"                          \
 161                ".previous"                                     \
 162                : "=r"(err)                                     \
 163                : "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
 164
 165#define __get_user_nocheck(x, ptr, size)                        \
 166({                                                              \
 167        long __gu_err, __gu_val;                                \
 168        __get_user_size(__gu_val, (ptr), (size), __gu_err);     \
 169        (x) = (__force __typeof__(*(ptr)))__gu_val;             \
 170        __gu_err;                                               \
 171})
 172
 173#define __get_user_check(x, ptr, size)                                  \
 174({                                                                      \
 175        long __gu_err = -EFAULT, __gu_val = 0;                          \
 176        const __typeof__(*(ptr)) * __gu_addr = (ptr);                   \
 177        if (access_ok(__gu_addr, size))                 \
 178                __get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
 179        (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 180        __gu_err;                                                       \
 181})
 182
 183extern long __get_user_bad(void);
 184
 185#define __get_user_size(x, ptr, size, retval)                           \
 186do {                                                                    \
 187        retval = 0;                                                     \
 188        switch (size) {                                                 \
 189        case 1: __get_user_asm(x, ptr, retval, "l.lbz"); break;         \
 190        case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break;         \
 191        case 4: __get_user_asm(x, ptr, retval, "l.lwz"); break;         \
 192        case 8: __get_user_asm2(x, ptr, retval); break;                 \
 193        default: (x) = __get_user_bad();                                \
 194        }                                                               \
 195} while (0)
 196
 197#define __get_user_asm(x, addr, err, op)                \
 198        __asm__ __volatile__(                           \
 199                "1:     "op" %1,0(%2)\n"                \
 200                "2:\n"                                  \
 201                ".section .fixup,\"ax\"\n"              \
 202                "3:     l.addi %0,r0,%3\n"              \
 203                "       l.addi %1,r0,0\n"               \
 204                "       l.j 2b\n"                       \
 205                "       l.nop\n"                        \
 206                ".previous\n"                           \
 207                ".section __ex_table,\"a\"\n"           \
 208                "       .align 2\n"                     \
 209                "       .long 1b,3b\n"                  \
 210                ".previous"                             \
 211                : "=r"(err), "=r"(x)                    \
 212                : "r"(addr), "i"(-EFAULT), "0"(err))
 213
 214#define __get_user_asm2(x, addr, err)                   \
 215        __asm__ __volatile__(                           \
 216                "1:     l.lwz %1,0(%2)\n"               \
 217                "2:     l.lwz %H1,4(%2)\n"              \
 218                "3:\n"                                  \
 219                ".section .fixup,\"ax\"\n"              \
 220                "4:     l.addi %0,r0,%3\n"              \
 221                "       l.addi %1,r0,0\n"               \
 222                "       l.addi %H1,r0,0\n"              \
 223                "       l.j 3b\n"                       \
 224                "       l.nop\n"                        \
 225                ".previous\n"                           \
 226                ".section __ex_table,\"a\"\n"           \
 227                "       .align 2\n"                     \
 228                "       .long 1b,4b\n"                  \
 229                "       .long 2b,4b\n"                  \
 230                ".previous"                             \
 231                : "=r"(err), "=&r"(x)                   \
 232                : "r"(addr), "i"(-EFAULT), "0"(err))
 233
 234/* more complex routines */
 235
 236extern unsigned long __must_check
 237__copy_tofrom_user(void *to, const void *from, unsigned long size);
 238static inline unsigned long
 239raw_copy_from_user(void *to, const void __user *from, unsigned long size)
 240{
 241        return __copy_tofrom_user(to, (__force const void *)from, size);
 242}
 243static inline unsigned long
 244raw_copy_to_user(void *to, const void __user *from, unsigned long size)
 245{
 246        return __copy_tofrom_user((__force void *)to, from, size);
 247}
 248#define INLINE_COPY_FROM_USER
 249#define INLINE_COPY_TO_USER
 250
 251extern unsigned long __clear_user(void *addr, unsigned long size);
 252
 253static inline __must_check unsigned long
 254clear_user(void *addr, unsigned long size)
 255{
 256        if (likely(access_ok(addr, size)))
 257                size = __clear_user(addr, size);
 258        return size;
 259}
 260
 261#define user_addr_max() \
 262        (uaccess_kernel() ? ~0UL : TASK_SIZE)
 263
 264extern long strncpy_from_user(char *dest, const char __user *src, long count);
 265
 266extern __must_check long strnlen_user(const char __user *str, long n);
 267
 268#endif /* __ASM_OPENRISC_UACCESS_H */
 269