arch/parisc/include/asm/uaccess.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __PARISC_UACCESS_H
   3 #define __PARISC_UACCESS_H
   4
   5 /*
   6  * User space memory access functions
   7  */
   8 #include <asm/page.h>
   9 #include <asm/cache.h>
  10
  11 #include <linux/bug.h>
  12 #include <linux/string.h>
  13
  14 #define TASK_SIZE_MAX DEFAULT_TASK_SIZE
  15 #include <asm/pgtable.h>
  16 #include <asm-generic/access_ok.h>
  17
  18 #define put_user __put_user
  19 #define get_user __get_user
  20
  21 #if !defined(CONFIG_64BIT)
  22 #define LDD_USER(sr, val, ptr)  __get_user_asm64(sr, val, ptr)
  23 #define STD_USER(sr, x, ptr)    __put_user_asm64(sr, x, ptr)
  24 #else
  25 #define LDD_USER(sr, val, ptr)  __get_user_asm(sr, val, "ldd", ptr)
  26 #define STD_USER(sr, x, ptr)    __put_user_asm(sr, "std", x, ptr)
  27 #endif
  28
  29 /*
  30  * The exception table contains two values: the first is the relative offset to
  31  * the address of the instruction that is allowed to fault, and the second is
  32  * the relative offset to the address of the fixup routine. Since relative
  33  * addresses are used, 32bit values are sufficient even on 64bit kernel.
  34  */
  35
  36 #define ARCH_HAS_RELATIVE_EXTABLE
  37 struct exception_table_entry {
  38         int insn;       /* relative address of insn that is allowed to fault. */
  39         int fixup;      /* relative address of fixup routine */
  40 };
  41
  42 #define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\
  43         ".section __ex_table,\"aw\"\n"                     \
  44         ".word (" #fault_addr " - .), (" #except_addr " - .)\n\t" \
  45         ".previous\n"
  46
  47 /*
  48  * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() creates a special exception table entry
  49  * (with lowest bit set) for which the fault handler in fixup_exception() will
  50  * load -EFAULT into %r29 for a read or write fault, and zeroes the target
  51  * register in case of a read fault in get_user().
  52  */
  53 #define ASM_EXCEPTIONTABLE_REG  29
  54 #define ASM_EXCEPTIONTABLE_VAR(__variable)              \
  55         register long __variable __asm__ ("r29") = 0
  56 #define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr )\
  57         ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1)
  58
  59 #define __get_user_internal(sr, val, ptr)               \
  60 ({                                                      \
  61         ASM_EXCEPTIONTABLE_VAR(__gu_err);               \
  62                                                         \
  63         switch (sizeof(*(ptr))) {                       \
  64         case 1: __get_user_asm(sr, val, "ldb", ptr); break; \
  65         case 2: __get_user_asm(sr, val, "ldh", ptr); break; \
  66         case 4: __get_user_asm(sr, val, "ldw", ptr); break; \
  67         case 8: LDD_USER(sr, val, ptr); break;          \
  68         default: BUILD_BUG();                           \
  69         }                                               \
  70                                                         \
  71         __gu_err;                                       \
  72 })
  73
  74 #define __get_user(val, ptr)                            \
  75 ({                                                      \
  76         __get_user_internal(SR_USER, val, ptr); \
  77 })
  78
  79 #define __get_user_asm(sr, val, ldx, ptr)               \
  80 {                                                       \
  81         register long __gu_val;                         \
  82                                                         \
  83         __asm__("1: " ldx " 0(%%sr%2,%3),%0\n"          \
  84                 "9:\n"                                  \
  85                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
  86                 : "=r"(__gu_val), "+r"(__gu_err)        \
  87                 : "i"(sr), "r"(ptr));                   \
  88                                                         \
  89         (val) = (__force __typeof__(*(ptr))) __gu_val;  \
  90 }
  91
  92 #define __get_kernel_nofault(dst, src, type, err_label) \
  93 {                                                       \
  94         type __z;                                       \
  95         long __err;                                     \
  96         __err = __get_user_internal(SR_KERNEL, __z, (type *)(src)); \
  97         if (unlikely(__err))                            \
  98                 goto err_label;                         \
  99         else                                            \
 100                 *(type *)(dst) = __z;                   \
 101 }
 102
 103
 104 #if !defined(CONFIG_64BIT)
 105
 106 #define __get_user_asm64(sr, val, ptr)                  \
 107 {                                                       \
 108         union {                                         \
 109                 unsigned long long      l;              \
 110                 __typeof__(*(ptr))      t;              \
 111         } __gu_tmp;                                     \
 112                                                         \
 113         __asm__("   copy %%r0,%R0\n"                    \
 114                 "1: ldw 0(%%sr%2,%3),%0\n"              \
 115                 "2: ldw 4(%%sr%2,%3),%R0\n"             \
 116                 "9:\n"                                  \
 117                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
 118                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \
 119                 : "=&r"(__gu_tmp.l), "+r"(__gu_err)     \
 120                 : "i"(sr), "r"(ptr));                   \
 121                                                         \
 122         (val) = __gu_tmp.t;                             \
 123 }
 124
 125 #endif /* !defined(CONFIG_64BIT) */
 126
 127
 128 #define __put_user_internal(sr, x, ptr)                         \
 129 ({                                                              \
 130         ASM_EXCEPTIONTABLE_VAR(__pu_err);                       \
 131                                                                 \
 132         switch (sizeof(*(ptr))) {                               \
 133         case 1: __put_user_asm(sr, "stb", x, ptr); break;       \
 134         case 2: __put_user_asm(sr, "sth", x, ptr); break;       \
 135         case 4: __put_user_asm(sr, "stw", x, ptr); break;       \
 136         case 8: STD_USER(sr, x, ptr); break;                    \
 137         default: BUILD_BUG();                                   \
 138         }                                                       \
 139                                                                 \
 140         __pu_err;                                               \
 141 })
 142
 143 #define __put_user(x, ptr)                                      \
 144 ({                                                              \
 145         __typeof__(&*(ptr)) __ptr = ptr;                        \
 146         __typeof__(*(__ptr)) __x = (__typeof__(*(__ptr)))(x);   \
 147         __put_user_internal(SR_USER, __x, __ptr);               \
 148 })
 149
 150 #define __put_kernel_nofault(dst, src, type, err_label)         \
 151 {                                                               \
 152         type __z = *(type *)(src);                              \
 153         long __err;                                             \
 154         __err = __put_user_internal(SR_KERNEL, __z, (type *)(dst)); \
 155         if (unlikely(__err))                                    \
 156                 goto err_label;                                 \
 157 }
 158
 159
 160
 161
 162 /*
 163  * The "__put_user/kernel_asm()" macros tell gcc they read from memory
 164  * instead of writing. This is because they do not write to any memory
 165  * gcc knows about, so there are no aliasing issues. These macros must
 166  * also be aware that fixups are executed in the context of the fault,
 167  * and any registers used there must be listed as clobbers.
 168  * The register holding the possible EFAULT error (ASM_EXCEPTIONTABLE_REG)
 169  * is already listed as input and output register.
 170  */
 171
 172 #define __put_user_asm(sr, stx, x, ptr)                         \
 173         __asm__ __volatile__ (                                  \
 174                 "1: " stx " %1,0(%%sr%2,%3)\n"                  \
 175                 "9:\n"                                          \
 176                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b)         \
 177                 : "+r"(__pu_err)                                \
 178                 : "r"(x), "i"(sr), "r"(ptr))
 179
 180
 181 #if !defined(CONFIG_64BIT)
 182
 183 #define __put_user_asm64(sr, __val, ptr) do {                   \
 184         __asm__ __volatile__ (                                  \
 185                 "1: stw %1,0(%%sr%2,%3)\n"                      \
 186                 "2: stw %R1,4(%%sr%2,%3)\n"                     \
 187                 "9:\n"                                          \
 188                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b)         \
 189                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b)         \
 190                 : "+r"(__pu_err)                                \
 191                 : "r"(__val), "i"(sr), "r"(ptr));               \
 192 } while (0)
 193
 194 #endif /* !defined(CONFIG_64BIT) */
 195
 196
 197 /*
 198  * Complex access routines -- external declarations
 199  */
 200
 201 extern long strncpy_from_user(char *, const char __user *, long);
 202 extern __must_check unsigned lclear_user(void __user *, unsigned long);
 203 extern __must_check long strnlen_user(const char __user *src, long n);
 204 /*
 205  * Complex access routines -- macros
 206  */
 207
 208 #define clear_user lclear_user
 209 #define __clear_user lclear_user
 210
 211 unsigned long __must_check raw_copy_to_user(void __user *dst, const void *src,
 212                                             unsigned long len);
 213 unsigned long __must_check raw_copy_from_user(void *dst, const void __user *src,
 214                                             unsigned long len);
 215 #define INLINE_COPY_TO_USER
 216 #define INLINE_COPY_FROM_USER
 217
 218 struct pt_regs;
 219 int fixup_exception(struct pt_regs *regs);
 220
 221 #endif /* __PARISC_UACCESS_H */