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 KERNEL_DS       ((mm_segment_t){0})
  15 #define USER_DS         ((mm_segment_t){1})
  16
  17 #define segment_eq(a, b) ((a).seg == (b).seg)
  18
  19 #define get_ds()        (KERNEL_DS)
  20 #define get_fs()        (current_thread_info()->addr_limit)
  21 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  22
  23 /*
  24  * Note that since kernel addresses are in a separate address space on
  25  * parisc, we don't need to do anything for access_ok().
  26  * We just let the page fault handler do the right thing. This also means
  27  * that put_user is the same as __put_user, etc.
  28  */
  29
  30 #define access_ok(type, uaddr, size)    \
  31         ( (uaddr) == (uaddr) )
  32
  33 #define put_user __put_user
  34 #define get_user __get_user
  35
  36 #if !defined(CONFIG_64BIT)
  37 #define LDD_USER(val, ptr)      __get_user_asm64(val, ptr)
  38 #define STD_USER(x, ptr)        __put_user_asm64(x, ptr)
  39 #else
  40 #define LDD_USER(val, ptr)      __get_user_asm(val, "ldd", ptr)
  41 #define STD_USER(x, ptr)        __put_user_asm("std", x, ptr)
  42 #endif
  43
  44 /*
  45  * The exception table contains two values: the first is the relative offset to
  46  * the address of the instruction that is allowed to fault, and the second is
  47  * the relative offset to the address of the fixup routine. Since relative
  48  * addresses are used, 32bit values are sufficient even on 64bit kernel.
  49  */
  50
  51 #define ARCH_HAS_RELATIVE_EXTABLE
  52 struct exception_table_entry {
  53         int insn;       /* relative address of insn that is allowed to fault. */
  54         int fixup;      /* relative address of fixup routine */
  55 };
  56
  57 #define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\
  58         ".section __ex_table,\"aw\"\n"                     \
  59         ".word (" #fault_addr " - .), (" #except_addr " - .)\n\t" \
  60         ".previous\n"
  61
  62 /*
  63  * ASM_EXCEPTIONTABLE_ENTRY_EFAULT() creates a special exception table entry
  64  * (with lowest bit set) for which the fault handler in fixup_exception() will
  65  * load -EFAULT into %r8 for a read or write fault, and zeroes the target
  66  * register in case of a read fault in get_user().
  67  */
  68 #define ASM_EXCEPTIONTABLE_ENTRY_EFAULT( fault_addr, except_addr )\
  69         ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr + 1)
  70
  71 /*
  72  * load_sr2() preloads the space register %%sr2 - based on the value of
  73  * get_fs() - with either a value of 0 to access kernel space (KERNEL_DS which
  74  * is 0), or with the current value of %%sr3 to access user space (USER_DS)
  75  * memory. The following __get_user_asm() and __put_user_asm() functions have
  76  * %%sr2 hard-coded to access the requested memory.
  77  */
  78 #define load_sr2() \
  79         __asm__(" or,=  %0,%%r0,%%r0\n\t"       \
  80                 " mfsp %%sr3,%0\n\t"            \
  81                 " mtsp %0,%%sr2\n\t"            \
  82                 : : "r"(get_fs()) : )
  83
  84 #define __get_user_internal(val, ptr)                   \
  85 ({                                                      \
  86         register long __gu_err __asm__ ("r8") = 0;      \
  87                                                         \
  88         switch (sizeof(*(ptr))) {                       \
  89         case 1: __get_user_asm(val, "ldb", ptr); break; \
  90         case 2: __get_user_asm(val, "ldh", ptr); break; \
  91         case 4: __get_user_asm(val, "ldw", ptr); break; \
  92         case 8: LDD_USER(val, ptr); break;              \
  93         default: BUILD_BUG();                           \
  94         }                                               \
  95                                                         \
  96         __gu_err;                                       \
  97 })
  98
  99 #define __get_user(val, ptr)                            \
 100 ({                                                      \
 101         load_sr2();                                     \
 102         __get_user_internal(val, ptr);                  \
 103 })
 104
 105 #define __get_user_asm(val, ldx, ptr)                   \
 106 {                                                       \
 107         register long __gu_val;                         \
 108                                                         \
 109         __asm__("1: " ldx " 0(%%sr2,%2),%0\n"           \
 110                 "9:\n"                                  \
 111                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
 112                 : "=r"(__gu_val), "=r"(__gu_err)        \
 113                 : "r"(ptr), "1"(__gu_err));             \
 114                                                         \
 115         (val) = (__force __typeof__(*(ptr))) __gu_val;  \
 116 }
 117
 118 #if !defined(CONFIG_64BIT)
 119
 120 #define __get_user_asm64(val, ptr)                      \
 121 {                                                       \
 122         union {                                         \
 123                 unsigned long long      l;              \
 124                 __typeof__(*(ptr))      t;              \
 125         } __gu_tmp;                                     \
 126                                                         \
 127         __asm__("   copy %%r0,%R0\n"                    \
 128                 "1: ldw 0(%%sr2,%2),%0\n"               \
 129                 "2: ldw 4(%%sr2,%2),%R0\n"              \
 130                 "9:\n"                                  \
 131                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
 132                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \
 133                 : "=&r"(__gu_tmp.l), "=r"(__gu_err)     \
 134                 : "r"(ptr), "1"(__gu_err));             \
 135                                                         \
 136         (val) = __gu_tmp.t;                             \
 137 }
 138
 139 #endif /* !defined(CONFIG_64BIT) */
 140
 141
 142 #define __put_user_internal(x, ptr)                             \
 143 ({                                                              \
 144         register long __pu_err __asm__ ("r8") = 0;              \
 145         __typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x);       \
 146                                                                 \
 147         switch (sizeof(*(ptr))) {                               \
 148         case 1: __put_user_asm("stb", __x, ptr); break;         \
 149         case 2: __put_user_asm("sth", __x, ptr); break;         \
 150         case 4: __put_user_asm("stw", __x, ptr); break;         \
 151         case 8: STD_USER(__x, ptr); break;                      \
 152         default: BUILD_BUG();                                   \
 153         }                                                       \
 154                                                                 \
 155         __pu_err;                                               \
 156 })
 157
 158 #define __put_user(x, ptr)                                      \
 159 ({                                                              \
 160         load_sr2();                                             \
 161         __put_user_internal(x, ptr);                            \
 162 })
 163
 164
 165 /*
 166  * The "__put_user/kernel_asm()" macros tell gcc they read from memory
 167  * instead of writing. This is because they do not write to any memory
 168  * gcc knows about, so there are no aliasing issues. These macros must
 169  * also be aware that fixups are executed in the context of the fault,
 170  * and any registers used there must be listed as clobbers.
 171  * r8 is already listed as err.
 172  */
 173
 174 #define __put_user_asm(stx, x, ptr)                         \
 175         __asm__ __volatile__ (                              \
 176                 "1: " stx " %2,0(%%sr2,%1)\n"               \
 177                 "9:\n"                                      \
 178                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b)     \
 179                 : "=r"(__pu_err)                            \
 180                 : "r"(ptr), "r"(x), "0"(__pu_err))
 181
 182
 183 #if !defined(CONFIG_64BIT)
 184
 185 #define __put_user_asm64(__val, ptr) do {                   \
 186         __asm__ __volatile__ (                              \
 187                 "1: stw %2,0(%%sr2,%1)\n"                   \
 188                 "2: stw %R2,4(%%sr2,%1)\n"                  \
 189                 "9:\n"                                      \
 190                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b)     \
 191                 ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b)     \
 192                 : "=r"(__pu_err)                            \
 193                 : "r"(ptr), "r"(__val), "0"(__pu_err));     \
 194 } while (0)
 195
 196 #endif /* !defined(CONFIG_64BIT) */
 197
 198
 199 /*
 200  * Complex access routines -- external declarations
 201  */
 202
 203 extern long strncpy_from_user(char *, const char __user *, long);
 204 extern unsigned lclear_user(void __user *, unsigned long);
 205 extern long lstrnlen_user(const char __user *, long);
 206 /*
 207  * Complex access routines -- macros
 208  */
 209 #define user_addr_max() (~0UL)
 210
 211 #define strnlen_user lstrnlen_user
 212 #define clear_user lclear_user
 213 #define __clear_user lclear_user
 214
 215 unsigned long __must_check raw_copy_to_user(void __user *dst, const void *src,
 216                                             unsigned long len);
 217 unsigned long __must_check raw_copy_from_user(void *dst, const void __user *src,
 218                                             unsigned long len);
 219 unsigned long __must_check raw_copy_in_user(void __user *dst, const void __user *src,
 220                                             unsigned long len);
 221 #define INLINE_COPY_TO_USER
 222 #define INLINE_COPY_FROM_USER
 223
 224 struct pt_regs;
 225 int fixup_exception(struct pt_regs *regs);
 226
 227 #endif /* __PARISC_UACCESS_H */