LXR linux/arch/nds32/include/asm/uaccess.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2// Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4#ifndef _ASMANDES_UACCESS_H
   5#define _ASMANDES_UACCESS_H
   6
   7/*
   8 * User space memory access functions
   9 */
  10#include <linux/sched.h>
  11#include <asm/errno.h>
  12#include <asm/memory.h>
  13#include <asm/types.h>
  14#include <linux/mm.h>
  15
  16#define __asmeq(x, y)  ".ifnc " x "," y " ; .err ; .endif\n\t"
  17
  18/*
  19 * The exception table consists of pairs of addresses: the first is the
  20 * address of an instruction that is allowed to fault, and the second is
  21 * the address at which the program should continue.  No registers are
  22 * modified, so it is entirely up to the continuation code to figure out
  23 * what to do.
  24 *
  25 * All the routines below use bits of fixup code that are out of line
  26 * with the main instruction path.  This means when everything is well,
  27 * we don't even have to jump over them.  Further, they do not intrude
  28 * on our cache or tlb entries.
  29 */
  30
  31struct exception_table_entry {
  32        unsigned long insn, fixup;
  33};
  34
  35extern int fixup_exception(struct pt_regs *regs);
  36
  37#define KERNEL_DS       ((mm_segment_t) { ~0UL })
  38#define USER_DS         ((mm_segment_t) {TASK_SIZE - 1})
  39
  40#define get_fs()        (current_thread_info()->addr_limit)
  41#define user_addr_max   get_fs
  42
  43static inline void set_fs(mm_segment_t fs)
  44{
  45        current_thread_info()->addr_limit = fs;
  46}
  47
  48#define segment_eq(a, b)        ((a) == (b))
  49
  50#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs() -size))
  51
  52#define access_ok(addr, size)   \
  53        __range_ok((unsigned long)addr, (unsigned long)size)
  54/*
  55 * Single-value transfer routines.  They automatically use the right
  56 * size if we just have the right pointer type.  Note that the functions
  57 * which read from user space (*get_*) need to take care not to leak
  58 * kernel data even if the calling code is buggy and fails to check
  59 * the return value.  This means zeroing out the destination variable
  60 * or buffer on error.  Normally this is done out of line by the
  61 * fixup code, but there are a few places where it intrudes on the
  62 * main code path.  When we only write to user space, there is no
  63 * problem.
  64 *
  65 * The "__xxx" versions of the user access functions do not verify the
  66 * address space - it must have been done previously with a separate
  67 * "access_ok()" call.
  68 *
  69 * The "xxx_error" versions set the third argument to EFAULT if an
  70 * error occurs, and leave it unchanged on success.  Note that these
  71 * versions are void (ie, don't return a value as such).
  72 */
  73
  74#define get_user        __get_user                                      \
  75
  76#define __get_user(x, ptr)                                              \
  77({                                                                      \
  78        long __gu_err = 0;                                              \
  79        __get_user_check((x), (ptr), __gu_err);                         \
  80        __gu_err;                                                       \
  81})
  82
  83#define __get_user_error(x, ptr, err)                                   \
  84({                                                                      \
  85        __get_user_check((x), (ptr), (err));                            \
  86        (void)0;                                                        \
  87})
  88
  89#define __get_user_check(x, ptr, err)                                   \
  90({                                                                      \
  91        const __typeof__(*(ptr)) __user *__p = (ptr);                   \
  92        might_fault();                                                  \
  93        if (access_ok(__p, sizeof(*__p))) {             \
  94                __get_user_err((x), __p, (err));                        \
  95        } else {                                                        \
  96                (x) = 0; (err) = -EFAULT;                               \
  97        }                                                               \
  98})
  99
 100#define __get_user_err(x, ptr, err)                                     \
 101do {                                                                    \
 102        unsigned long __gu_val;                                         \
 103        __chk_user_ptr(ptr);                                            \
 104        switch (sizeof(*(ptr))) {                                       \
 105        case 1:                                                         \
 106                __get_user_asm("lbi", __gu_val, (ptr), (err));          \
 107                break;                                                  \
 108        case 2:                                                         \
 109                __get_user_asm("lhi", __gu_val, (ptr), (err));          \
 110                break;                                                  \
 111        case 4:                                                         \
 112                __get_user_asm("lwi", __gu_val, (ptr), (err));          \
 113                break;                                                  \
 114        case 8:                                                         \
 115                __get_user_asm_dword(__gu_val, (ptr), (err));           \
 116                break;                                                  \
 117        default:                                                        \
 118                BUILD_BUG();                                            \
 119                break;                                                  \
 120        }                                                               \
 121        (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 122} while (0)
 123
 124#define __get_user_asm(inst, x, addr, err)                              \
 125        __asm__ __volatile__ (                                          \
 126                "1:     "inst"  %1,[%2]\n"                              \
 127                "2:\n"                                                  \
 128                "       .section .fixup,\"ax\"\n"                       \
 129                "       .align  2\n"                                    \
 130                "3:     move %0, %3\n"                                  \
 131                "       move %1, #0\n"                                  \
 132                "       b       2b\n"                                   \
 133                "       .previous\n"                                    \
 134                "       .section __ex_table,\"a\"\n"                    \
 135                "       .align  3\n"                                    \
 136                "       .long   1b, 3b\n"                               \
 137                "       .previous"                                      \
 138                : "+r" (err), "=&r" (x)                                 \
 139                : "r" (addr), "i" (-EFAULT)                             \
 140                : "cc")
 141
 142#ifdef __NDS32_EB__
 143#define __gu_reg_oper0 "%H1"
 144#define __gu_reg_oper1 "%L1"
 145#else
 146#define __gu_reg_oper0 "%L1"
 147#define __gu_reg_oper1 "%H1"
 148#endif
 149
 150#define __get_user_asm_dword(x, addr, err)                              \
 151        __asm__ __volatile__ (                                          \
 152                "\n1:\tlwi " __gu_reg_oper0 ",[%2]\n"                   \
 153                "\n2:\tlwi " __gu_reg_oper1 ",[%2+4]\n"                 \
 154                "3:\n"                                                  \
 155                "       .section .fixup,\"ax\"\n"                       \
 156                "       .align  2\n"                                    \
 157                "4:     move    %0, %3\n"                               \
 158                "       b       3b\n"                                   \
 159                "       .previous\n"                                    \
 160                "       .section __ex_table,\"a\"\n"                    \
 161                "       .align  3\n"                                    \
 162                "       .long   1b, 4b\n"                               \
 163                "       .long   2b, 4b\n"                               \
 164                "       .previous"                                      \
 165                : "+r"(err), "=&r"(x)                                   \
 166                : "r"(addr), "i"(-EFAULT)                               \
 167                : "cc")
 168
 169#define put_user        __put_user                                      \
 170
 171#define __put_user(x, ptr)                                              \
 172({                                                                      \
 173        long __pu_err = 0;                                              \
 174        __put_user_err((x), (ptr), __pu_err);                           \
 175        __pu_err;                                                       \
 176})
 177
 178#define __put_user_error(x, ptr, err)                                   \
 179({                                                                      \
 180        __put_user_err((x), (ptr), (err));                              \
 181        (void)0;                                                        \
 182})
 183
 184#define __put_user_check(x, ptr, err)                                   \
 185({                                                                      \
 186        __typeof__(*(ptr)) __user *__p = (ptr);                         \
 187        might_fault();                                                  \
 188        if (access_ok(__p, sizeof(*__p))) {             \
 189                __put_user_err((x), __p, (err));                        \
 190        } else  {                                                       \
 191                (err) = -EFAULT;                                        \
 192        }                                                               \
 193})
 194
 195#define __put_user_err(x, ptr, err)                                     \
 196do {                                                                    \
 197        __typeof__(*(ptr)) __pu_val = (x);                              \
 198        __chk_user_ptr(ptr);                                            \
 199        switch (sizeof(*(ptr))) {                                       \
 200        case 1:                                                         \
 201                __put_user_asm("sbi", __pu_val, (ptr), (err));          \
 202                break;                                                  \
 203        case 2:                                                         \
 204                __put_user_asm("shi", __pu_val, (ptr), (err));          \
 205                break;                                                  \
 206        case 4:                                                         \
 207                __put_user_asm("swi", __pu_val, (ptr), (err));          \
 208                break;                                                  \
 209        case 8:                                                         \
 210                __put_user_asm_dword(__pu_val, (ptr), (err));           \
 211                break;                                                  \
 212        default:                                                        \
 213                BUILD_BUG();                                            \
 214                break;                                                  \
 215        }                                                               \
 216} while (0)
 217
 218#define __put_user_asm(inst, x, addr, err)                              \
 219        __asm__ __volatile__ (                                          \
 220                "1:     "inst"  %1,[%2]\n"                              \
 221                "2:\n"                                                  \
 222                "       .section .fixup,\"ax\"\n"                       \
 223                "       .align  2\n"                                    \
 224                "3:     move    %0, %3\n"                               \
 225                "       b       2b\n"                                   \
 226                "       .previous\n"                                    \
 227                "       .section __ex_table,\"a\"\n"                    \
 228                "       .align  3\n"                                    \
 229                "       .long   1b, 3b\n"                               \
 230                "       .previous"                                      \
 231                : "+r" (err)                                            \
 232                : "r" (x), "r" (addr), "i" (-EFAULT)                    \
 233                : "cc")
 234
 235#ifdef __NDS32_EB__
 236#define __pu_reg_oper0 "%H2"
 237#define __pu_reg_oper1 "%L2"
 238#else
 239#define __pu_reg_oper0 "%L2"
 240#define __pu_reg_oper1 "%H2"
 241#endif
 242
 243#define __put_user_asm_dword(x, addr, err)                              \
 244        __asm__ __volatile__ (                                          \
 245                "\n1:\tswi " __pu_reg_oper0 ",[%1]\n"                   \
 246                "\n2:\tswi " __pu_reg_oper1 ",[%1+4]\n"                 \
 247                "3:\n"                                                  \
 248                "       .section .fixup,\"ax\"\n"                       \
 249                "       .align  2\n"                                    \
 250                "4:     move    %0, %3\n"                               \
 251                "       b       3b\n"                                   \
 252                "       .previous\n"                                    \
 253                "       .section __ex_table,\"a\"\n"                    \
 254                "       .align  3\n"                                    \
 255                "       .long   1b, 4b\n"                               \
 256                "       .long   2b, 4b\n"                               \
 257                "       .previous"                                      \
 258                : "+r"(err)                                             \
 259                : "r"(addr), "r"(x), "i"(-EFAULT)                       \
 260                : "cc")
 261
 262extern unsigned long __arch_clear_user(void __user * addr, unsigned long n);
 263extern long strncpy_from_user(char *dest, const char __user * src, long count);
 264extern __must_check long strlen_user(const char __user * str);
 265extern __must_check long strnlen_user(const char __user * str, long n);
 266extern unsigned long __arch_copy_from_user(void *to, const void __user * from,
 267                                           unsigned long n);
 268extern unsigned long __arch_copy_to_user(void __user * to, const void *from,
 269                                         unsigned long n);
 270
 271#define raw_copy_from_user __arch_copy_from_user
 272#define raw_copy_to_user __arch_copy_to_user
 273
 274#define INLINE_COPY_FROM_USER
 275#define INLINE_COPY_TO_USER
 276static inline unsigned long clear_user(void __user * to, unsigned long n)
 277{
 278        if (access_ok(to, n))
 279                n = __arch_clear_user(to, n);
 280        return n;
 281}
 282
 283static inline unsigned long __clear_user(void __user * to, unsigned long n)
 284{
 285        return __arch_clear_user(to, n);
 286}
 287
 288#endif /* _ASMNDS32_UACCESS_H */
 289