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