linux/arch/microblaze/include/asm/uaccess.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
   4 * Copyright (C) 2008-2009 PetaLogix
   5 * Copyright (C) 2006 Atmark Techno, Inc.
   6 */
   7
   8#ifndef _ASM_MICROBLAZE_UACCESS_H
   9#define _ASM_MICROBLAZE_UACCESS_H
  10
  11#include <linux/kernel.h>
  12
  13#include <asm/mmu.h>
  14#include <asm/page.h>
  15#include <linux/pgtable.h>
  16#include <asm/extable.h>
  17#include <linux/string.h>
  18
  19/*
  20 * On Microblaze the fs value is actually the top of the corresponding
  21 * address space.
  22 *
  23 * The fs value determines whether argument validity checking should be
  24 * performed or not. If get_fs() == USER_DS, checking is performed, with
  25 * get_fs() == KERNEL_DS, checking is bypassed.
  26 *
  27 * For historical reasons, these macros are grossly misnamed.
  28 *
  29 * For non-MMU arch like Microblaze, KERNEL_DS and USER_DS is equal.
  30 */
  31# define MAKE_MM_SEG(s)       ((mm_segment_t) { (s) })
  32
  33#  define KERNEL_DS     MAKE_MM_SEG(0xFFFFFFFF)
  34#  define USER_DS       MAKE_MM_SEG(TASK_SIZE - 1)
  35
  36# define get_fs()       (current_thread_info()->addr_limit)
  37# define set_fs(val)    (current_thread_info()->addr_limit = (val))
  38
  39# define uaccess_kernel()       (get_fs().seg == KERNEL_DS.seg)
  40
  41static inline int access_ok(const void __user *addr, unsigned long size)
  42{
  43        if (!size)
  44                goto ok;
  45
  46        if ((get_fs().seg < ((unsigned long)addr)) ||
  47                        (get_fs().seg < ((unsigned long)addr + size - 1))) {
  48                pr_devel("ACCESS fail at 0x%08x (size 0x%x), seg 0x%08x\n",
  49                        (__force u32)addr, (u32)size,
  50                        (u32)get_fs().seg);
  51                return 0;
  52        }
  53ok:
  54        pr_devel("ACCESS OK at 0x%08x (size 0x%x), seg 0x%08x\n",
  55                        (__force u32)addr, (u32)size,
  56                        (u32)get_fs().seg);
  57        return 1;
  58}
  59
  60# define __FIXUP_SECTION        ".section .fixup,\"ax\"\n"
  61# define __EX_TABLE_SECTION     ".section __ex_table,\"a\"\n"
  62
  63extern unsigned long __copy_tofrom_user(void __user *to,
  64                const void __user *from, unsigned long size);
  65
  66/* Return: number of not copied bytes, i.e. 0 if OK or non-zero if fail. */
  67static inline unsigned long __must_check __clear_user(void __user *to,
  68                                                        unsigned long n)
  69{
  70        /* normal memset with two words to __ex_table */
  71        __asm__ __volatile__ (                          \
  72                        "1:     sb      r0, %1, r0;"    \
  73                        "       addik   %0, %0, -1;"    \
  74                        "       bneid   %0, 1b;"        \
  75                        "       addik   %1, %1, 1;"     \
  76                        "2:                     "       \
  77                        __EX_TABLE_SECTION              \
  78                        ".word  1b,2b;"                 \
  79                        ".previous;"                    \
  80                : "=r"(n), "=r"(to)                     \
  81                : "0"(n), "1"(to)
  82        );
  83        return n;
  84}
  85
  86static inline unsigned long __must_check clear_user(void __user *to,
  87                                                        unsigned long n)
  88{
  89        might_fault();
  90        if (unlikely(!access_ok(to, n)))
  91                return n;
  92
  93        return __clear_user(to, n);
  94}
  95
  96/* put_user and get_user macros */
  97extern long __user_bad(void);
  98
  99#define __get_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 100({                                                              \
 101        __asm__ __volatile__ (                                  \
 102                        "1:"    insn    " %1, %2, r0;"          \
 103                        "       addk    %0, r0, r0;"            \
 104                        "2:                     "               \
 105                        __FIXUP_SECTION                         \
 106                        "3:     brid    2b;"                    \
 107                        "       addik   %0, r0, %3;"            \
 108                        ".previous;"                            \
 109                        __EX_TABLE_SECTION                      \
 110                        ".word  1b,3b;"                         \
 111                        ".previous;"                            \
 112                : "=&r"(__gu_err), "=r"(__gu_val)               \
 113                : "r"(__gu_ptr), "i"(-EFAULT)                   \
 114        );                                                      \
 115})
 116
 117/**
 118 * get_user: - Get a simple variable from user space.
 119 * @x:   Variable to store result.
 120 * @ptr: Source address, in user space.
 121 *
 122 * Context: User context only. This function may sleep if pagefaults are
 123 *          enabled.
 124 *
 125 * This macro copies a single simple variable from user space to kernel
 126 * space.  It supports simple types like char and int, but not larger
 127 * data types like structures or arrays.
 128 *
 129 * @ptr must have pointer-to-simple-variable type, and the result of
 130 * dereferencing @ptr must be assignable to @x without a cast.
 131 *
 132 * Returns zero on success, or -EFAULT on error.
 133 * On error, the variable @x is set to zero.
 134 */
 135#define get_user(x, ptr) ({                             \
 136        const typeof(*(ptr)) __user *__gu_ptr = (ptr);  \
 137        access_ok(__gu_ptr, sizeof(*__gu_ptr)) ?        \
 138                __get_user(x, __gu_ptr) : -EFAULT;      \
 139})
 140
 141#define __get_user(x, ptr)                                              \
 142({                                                                      \
 143        unsigned long __gu_val = 0;                                     \
 144        long __gu_err;                                                  \
 145        switch (sizeof(*(ptr))) {                                       \
 146        case 1:                                                         \
 147                __get_user_asm("lbu", (ptr), __gu_val, __gu_err);       \
 148                break;                                                  \
 149        case 2:                                                         \
 150                __get_user_asm("lhu", (ptr), __gu_val, __gu_err);       \
 151                break;                                                  \
 152        case 4:                                                         \
 153                __get_user_asm("lw", (ptr), __gu_val, __gu_err);        \
 154                break;                                                  \
 155        case 8:                                                         \
 156                __gu_err = __copy_from_user(&__gu_val, ptr, 8);         \
 157                if (__gu_err)                                           \
 158                        __gu_err = -EFAULT;                             \
 159                break;                                                  \
 160        default:                                                        \
 161                /* __gu_val = 0; __gu_err = -EINVAL;*/ __gu_err = __user_bad();\
 162        }                                                               \
 163        x = (__force __typeof__(*(ptr))) __gu_val;                      \
 164        __gu_err;                                                       \
 165})
 166
 167
 168#define __put_user_asm(insn, __gu_ptr, __gu_val, __gu_err)      \
 169({                                                              \
 170        __asm__ __volatile__ (                                  \
 171                        "1:"    insn    " %1, %2, r0;"          \
 172                        "       addk    %0, r0, r0;"            \
 173                        "2:                     "               \
 174                        __FIXUP_SECTION                         \
 175                        "3:     brid    2b;"                    \
 176                        "       addik   %0, r0, %3;"            \
 177                        ".previous;"                            \
 178                        __EX_TABLE_SECTION                      \
 179                        ".word  1b,3b;"                         \
 180                        ".previous;"                            \
 181                : "=&r"(__gu_err)                               \
 182                : "r"(__gu_val), "r"(__gu_ptr), "i"(-EFAULT)    \
 183        );                                                      \
 184})
 185
 186#define __put_user_asm_8(__gu_ptr, __gu_val, __gu_err)          \
 187({                                                              \
 188        __asm__ __volatile__ (" lwi     %0, %1, 0;"             \
 189                        "1:     swi     %0, %2, 0;"             \
 190                        "       lwi     %0, %1, 4;"             \
 191                        "2:     swi     %0, %2, 4;"             \
 192                        "       addk    %0, r0, r0;"            \
 193                        "3:                     "               \
 194                        __FIXUP_SECTION                         \
 195                        "4:     brid    3b;"                    \
 196                        "       addik   %0, r0, %3;"            \
 197                        ".previous;"                            \
 198                        __EX_TABLE_SECTION                      \
 199                        ".word  1b,4b,2b,4b;"                   \
 200                        ".previous;"                            \
 201                : "=&r"(__gu_err)                               \
 202                : "r"(&__gu_val), "r"(__gu_ptr), "i"(-EFAULT)   \
 203                );                                              \
 204})
 205
 206/**
 207 * put_user: - Write a simple value into user space.
 208 * @x:   Value to copy to user space.
 209 * @ptr: Destination address, in user space.
 210 *
 211 * Context: User context only. This function may sleep if pagefaults are
 212 *          enabled.
 213 *
 214 * This macro copies a single simple value from kernel space to user
 215 * space.  It supports simple types like char and int, but not larger
 216 * data types like structures or arrays.
 217 *
 218 * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 219 * to the result of dereferencing @ptr.
 220 *
 221 * Returns zero on success, or -EFAULT on error.
 222 */
 223#define put_user(x, ptr)                                                \
 224        __put_user_check((x), (ptr), sizeof(*(ptr)))
 225
 226#define __put_user_check(x, ptr, size)                                  \
 227({                                                                      \
 228        typeof(*(ptr)) volatile __pu_val = x;                           \
 229        typeof(*(ptr)) __user *__pu_addr = (ptr);                       \
 230        int __pu_err = 0;                                               \
 231                                                                        \
 232        if (access_ok(__pu_addr, size)) {                       \
 233                switch (size) {                                         \
 234                case 1:                                                 \
 235                        __put_user_asm("sb", __pu_addr, __pu_val,       \
 236                                       __pu_err);                       \
 237                        break;                                          \
 238                case 2:                                                 \
 239                        __put_user_asm("sh", __pu_addr, __pu_val,       \
 240                                       __pu_err);                       \
 241                        break;                                          \
 242                case 4:                                                 \
 243                        __put_user_asm("sw", __pu_addr, __pu_val,       \
 244                                       __pu_err);                       \
 245                        break;                                          \
 246                case 8:                                                 \
 247                        __put_user_asm_8(__pu_addr, __pu_val, __pu_err);\
 248                        break;                                          \
 249                default:                                                \
 250                        __pu_err = __user_bad();                        \
 251                        break;                                          \
 252                }                                                       \
 253        } else {                                                        \
 254                __pu_err = -EFAULT;                                     \
 255        }                                                               \
 256        __pu_err;                                                       \
 257})
 258
 259#define __put_user(x, ptr)                                              \
 260({                                                                      \
 261        __typeof__(*(ptr)) volatile __gu_val = (x);                     \
 262        long __gu_err = 0;                                              \
 263        switch (sizeof(__gu_val)) {                                     \
 264        case 1:                                                         \
 265                __put_user_asm("sb", (ptr), __gu_val, __gu_err);        \
 266                break;                                                  \
 267        case 2:                                                         \
 268                __put_user_asm("sh", (ptr), __gu_val, __gu_err);        \
 269                break;                                                  \
 270        case 4:                                                         \
 271                __put_user_asm("sw", (ptr), __gu_val, __gu_err);        \
 272                break;                                                  \
 273        case 8:                                                         \
 274                __put_user_asm_8((ptr), __gu_val, __gu_err);            \
 275                break;                                                  \
 276        default:                                                        \
 277                /*__gu_err = -EINVAL;*/ __gu_err = __user_bad();        \
 278        }                                                               \
 279        __gu_err;                                                       \
 280})
 281
 282static inline unsigned long
 283raw_copy_from_user(void *to, const void __user *from, unsigned long n)
 284{
 285        return __copy_tofrom_user((__force void __user *)to, from, n);
 286}
 287
 288static inline unsigned long
 289raw_copy_to_user(void __user *to, const void *from, unsigned long n)
 290{
 291        return __copy_tofrom_user(to, (__force const void __user *)from, n);
 292}
 293#define INLINE_COPY_FROM_USER
 294#define INLINE_COPY_TO_USER
 295
 296/*
 297 * Copy a null terminated string from userspace.
 298 */
 299extern int __strncpy_user(char *to, const char __user *from, int len);
 300
 301static inline long
 302strncpy_from_user(char *dst, const char __user *src, long count)
 303{
 304        if (!access_ok(src, 1))
 305                return -EFAULT;
 306        return __strncpy_user(dst, src, count);
 307}
 308
 309/*
 310 * Return the size of a string (including the ending 0)
 311 *
 312 * Return 0 on exception, a value greater than N if too long
 313 */
 314extern int __strnlen_user(const char __user *sstr, int len);
 315
 316static inline long strnlen_user(const char __user *src, long n)
 317{
 318        if (!access_ok(src, 1))
 319                return 0;
 320        return __strnlen_user(src, n);
 321}
 322
 323#endif /* _ASM_MICROBLAZE_UACCESS_H */
 324