arch/parisc/include/asm/uaccess.h

   1 #ifndef __PARISC_UACCESS_H
   2 #define __PARISC_UACCESS_H
   3
   4 /*
   5  * User space memory access functions
   6  */
   7 #include <asm/page.h>
   8 #include <asm/cache.h>
   9 #include <asm/errno.h>
  10 #include <asm-generic/uaccess-unaligned.h>
  11
  12 #include <linux/bug.h>
  13
  14 #define VERIFY_READ 0
  15 #define VERIFY_WRITE 1
  16
  17 #define KERNEL_DS       ((mm_segment_t){0})
  18 #define USER_DS         ((mm_segment_t){1})
  19
  20 #define segment_eq(a, b) ((a).seg == (b).seg)
  21
  22 #define get_ds()        (KERNEL_DS)
  23 #define get_fs()        (current_thread_info()->addr_limit)
  24 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  25
  26 /*
  27  * Note that since kernel addresses are in a separate address space on
  28  * parisc, we don't need to do anything for access_ok().
  29  * We just let the page fault handler do the right thing. This also means
  30  * that put_user is the same as __put_user, etc.
  31  */
  32
  33 static inline long access_ok(int type, const void __user * addr,
  34                 unsigned long size)
  35 {
  36         return 1;
  37 }
  38
  39 #define put_user __put_user
  40 #define get_user __get_user
  41
  42 #if !defined(CONFIG_64BIT)
  43 #define LDD_USER(ptr)           __get_user_asm64(ptr)
  44 #define STD_USER(x, ptr)        __put_user_asm64(x, ptr)
  45 #else
  46 #define LDD_USER(ptr)           __get_user_asm("ldd", ptr)
  47 #define STD_USER(x, ptr)        __put_user_asm("std", x, ptr)
  48 #endif
  49
  50 /*
  51  * The exception table contains two values: the first is the relative offset to
  52  * the address of the instruction that is allowed to fault, and the second is
  53  * the relative offset to the address of the fixup routine. Since relative
  54  * addresses are used, 32bit values are sufficient even on 64bit kernel.
  55  */
  56
  57 #define ARCH_HAS_RELATIVE_EXTABLE
  58 struct exception_table_entry {
  59         int insn;       /* relative address of insn that is allowed to fault. */
  60         int fixup;      /* relative address of fixup routine */
  61 };
  62
  63 #define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\
  64         ".section __ex_table,\"aw\"\n"                     \
  65         ".word (" #fault_addr " - .), (" #except_addr " - .)\n\t" \
  66         ".previous\n"
  67
  68 /*
  69  * The page fault handler stores, in a per-cpu area, the following information
  70  * if a fixup routine is available.
  71  */
  72 struct exception_data {
  73         unsigned long fault_ip;
  74         unsigned long fault_gp;
  75         unsigned long fault_space;
  76         unsigned long fault_addr;
  77 };
  78
  79 /*
  80  * load_sr2() preloads the space register %%sr2 - based on the value of
  81  * get_fs() - with either a value of 0 to access kernel space (KERNEL_DS which
  82  * is 0), or with the current value of %%sr3 to access user space (USER_DS)
  83  * memory. The following __get_user_asm() and __put_user_asm() functions have
  84  * %%sr2 hard-coded to access the requested memory.
  85  */
  86 #define load_sr2() \
  87         __asm__(" or,=  %0,%%r0,%%r0\n\t"       \
  88                 " mfsp %%sr3,%0\n\t"            \
  89                 " mtsp %0,%%sr2\n\t"            \
  90                 : : "r"(get_fs()) : )
  91
  92 #define __get_user(x, ptr)                               \
  93 ({                                                       \
  94         register long __gu_err __asm__ ("r8") = 0;       \
  95         register long __gu_val __asm__ ("r9") = 0;       \
  96                                                          \
  97         load_sr2();                                      \
  98         switch (sizeof(*(ptr))) {                        \
  99             case 1: __get_user_asm("ldb", ptr); break;   \
 100             case 2: __get_user_asm("ldh", ptr); break;   \
 101             case 4: __get_user_asm("ldw", ptr); break;   \
 102             case 8: LDD_USER(ptr);  break;               \
 103             default: BUILD_BUG(); break;                 \
 104         }                                                \
 105                                                          \
 106         (x) = (__force __typeof__(*(ptr))) __gu_val;     \
 107         __gu_err;                                        \
 108 })
 109
 110 #define __get_user_asm(ldx, ptr)                        \
 111         __asm__("\n1:\t" ldx "\t0(%%sr2,%2),%0\n\t"     \
 112                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_1)\
 113                 : "=r"(__gu_val), "=r"(__gu_err)        \
 114                 : "r"(ptr), "1"(__gu_err)               \
 115                 : "r1");
 116
 117 #if !defined(CONFIG_64BIT)
 118
 119 #define __get_user_asm64(ptr)                           \
 120         __asm__("\n1:\tldw 0(%%sr2,%2),%0"              \
 121                 "\n2:\tldw 4(%%sr2,%2),%R0\n\t"         \
 122                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_2)\
 123                 ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_get_user_skip_1)\
 124                 : "=r"(__gu_val), "=r"(__gu_err)        \
 125                 : "r"(ptr), "1"(__gu_err)               \
 126                 : "r1");
 127
 128 #endif /* !defined(CONFIG_64BIT) */
 129
 130
 131 #define __put_user(x, ptr)                                      \
 132 ({                                                              \
 133         register long __pu_err __asm__ ("r8") = 0;              \
 134         __typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x);       \
 135                                                                 \
 136         load_sr2();                                             \
 137         switch (sizeof(*(ptr))) {                               \
 138             case 1: __put_user_asm("stb", __x, ptr); break;     \
 139             case 2: __put_user_asm("sth", __x, ptr); break;     \
 140             case 4: __put_user_asm("stw", __x, ptr); break;     \
 141             case 8: STD_USER(__x, ptr); break;                  \
 142             default: BUILD_BUG(); break;                        \
 143         }                                                       \
 144                                                                 \
 145         __pu_err;                                               \
 146 })
 147
 148 /*
 149  * The "__put_user/kernel_asm()" macros tell gcc they read from memory
 150  * instead of writing. This is because they do not write to any memory
 151  * gcc knows about, so there are no aliasing issues. These macros must
 152  * also be aware that "fixup_put_user_skip_[12]" are executed in the
 153  * context of the fault, and any registers used there must be listed
 154  * as clobbers. In this case only "r1" is used by the current routines.
 155  * r8/r9 are already listed as err/val.
 156  */
 157
 158 #define __put_user_asm(stx, x, ptr)                         \
 159         __asm__ __volatile__ (                              \
 160                 "\n1:\t" stx "\t%2,0(%%sr2,%1)\n\t"         \
 161                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_1)\
 162                 : "=r"(__pu_err)                            \
 163                 : "r"(ptr), "r"(x), "0"(__pu_err)           \
 164                 : "r1")
 165
 166
 167 #if !defined(CONFIG_64BIT)
 168
 169 #define __put_user_asm64(__val, ptr) do {                   \
 170         __asm__ __volatile__ (                              \
 171                 "\n1:\tstw %2,0(%%sr2,%1)"                  \
 172                 "\n2:\tstw %R2,4(%%sr2,%1)\n\t"             \
 173                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_2)\
 174                 ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_put_user_skip_1)\
 175                 : "=r"(__pu_err)                            \
 176                 : "r"(ptr), "r"(__val), "0"(__pu_err) \
 177                 : "r1");                                    \
 178 } while (0)
 179
 180 #endif /* !defined(CONFIG_64BIT) */
 181
 182
 183 /*
 184  * Complex access routines -- external declarations
 185  */
 186
 187 extern unsigned long lcopy_to_user(void __user *, const void *, unsigned long);
 188 extern unsigned long lcopy_from_user(void *, const void __user *, unsigned long);
 189 extern unsigned long lcopy_in_user(void __user *, const void __user *, unsigned long);
 190 extern long strncpy_from_user(char *, const char __user *, long);
 191 extern unsigned lclear_user(void __user *, unsigned long);
 192 extern long lstrnlen_user(const char __user *, long);
 193 /*
 194  * Complex access routines -- macros
 195  */
 196 #define user_addr_max() (~0UL)
 197
 198 #define strnlen_user lstrnlen_user
 199 #define strlen_user(str) lstrnlen_user(str, 0x7fffffffL)
 200 #define clear_user lclear_user
 201 #define __clear_user lclear_user
 202
 203 unsigned long copy_to_user(void __user *dst, const void *src, unsigned long len);
 204 #define __copy_to_user copy_to_user
 205 unsigned long __copy_from_user(void *dst, const void __user *src, unsigned long len);
 206 unsigned long copy_in_user(void __user *dst, const void __user *src, unsigned long len);
 207 #define __copy_in_user copy_in_user
 208 #define __copy_to_user_inatomic __copy_to_user
 209 #define __copy_from_user_inatomic __copy_from_user
 210
 211 extern void copy_from_user_overflow(void)
 212 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 213         __compiletime_error("copy_from_user() buffer size is not provably correct")
 214 #else
 215         __compiletime_warning("copy_from_user() buffer size is not provably correct")
 216 #endif
 217 ;
 218
 219 static inline unsigned long __must_check copy_from_user(void *to,
 220                                           const void __user *from,
 221                                           unsigned long n)
 222 {
 223         int sz = __compiletime_object_size(to);
 224         int ret = -EFAULT;
 225
 226         if (likely(sz == -1 || !__builtin_constant_p(n) || sz >= n))
 227                 ret = __copy_from_user(to, from, n);
 228         else
 229                 copy_from_user_overflow();
 230
 231         return ret;
 232 }
 233
 234 struct pt_regs;
 235 int fixup_exception(struct pt_regs *regs);
 236
 237 #endif /* __PARISC_UACCESS_H */