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 #include <linux/string.h>
  14
  15 #define VERIFY_READ 0
  16 #define VERIFY_WRITE 1
  17
  18 #define KERNEL_DS       ((mm_segment_t){0})
  19 #define USER_DS         ((mm_segment_t){1})
  20
  21 #define segment_eq(a, b) ((a).seg == (b).seg)
  22
  23 #define get_ds()        (KERNEL_DS)
  24 #define get_fs()        (current_thread_info()->addr_limit)
  25 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  26
  27 /*
  28  * Note that since kernel addresses are in a separate address space on
  29  * parisc, we don't need to do anything for access_ok().
  30  * We just let the page fault handler do the right thing. This also means
  31  * that put_user is the same as __put_user, etc.
  32  */
  33
  34 static inline long access_ok(int type, const void __user * addr,
  35                 unsigned long size)
  36 {
  37         return 1;
  38 }
  39
  40 #define put_user __put_user
  41 #define get_user __get_user
  42
  43 #if !defined(CONFIG_64BIT)
  44 #define LDD_USER(ptr)           __get_user_asm64(ptr)
  45 #define STD_USER(x, ptr)        __put_user_asm64(x, ptr)
  46 #else
  47 #define LDD_USER(ptr)           __get_user_asm("ldd", ptr)
  48 #define STD_USER(x, ptr)        __put_user_asm("std", x, ptr)
  49 #endif
  50
  51 /*
  52  * The exception table contains two values: the first is the relative offset to
  53  * the address of the instruction that is allowed to fault, and the second is
  54  * the relative offset to the address of the fixup routine. Since relative
  55  * addresses are used, 32bit values are sufficient even on 64bit kernel.
  56  */
  57
  58 #define ARCH_HAS_RELATIVE_EXTABLE
  59 struct exception_table_entry {
  60         int insn;       /* relative address of insn that is allowed to fault. */
  61         int fixup;      /* relative address of fixup routine */
  62 };
  63
  64 #define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\
  65         ".section __ex_table,\"aw\"\n"                     \
  66         ".word (" #fault_addr " - .), (" #except_addr " - .)\n\t" \
  67         ".previous\n"
  68
  69 /*
  70  * The page fault handler stores, in a per-cpu area, the following information
  71  * if a fixup routine is available.
  72  */
  73 struct exception_data {
  74         unsigned long fault_ip;
  75         unsigned long fault_gp;
  76         unsigned long fault_space;
  77         unsigned long fault_addr;
  78 };
  79
  80 /*
  81  * load_sr2() preloads the space register %%sr2 - based on the value of
  82  * get_fs() - with either a value of 0 to access kernel space (KERNEL_DS which
  83  * is 0), or with the current value of %%sr3 to access user space (USER_DS)
  84  * memory. The following __get_user_asm() and __put_user_asm() functions have
  85  * %%sr2 hard-coded to access the requested memory.
  86  */
  87 #define load_sr2() \
  88         __asm__(" or,=  %0,%%r0,%%r0\n\t"       \
  89                 " mfsp %%sr3,%0\n\t"            \
  90                 " mtsp %0,%%sr2\n\t"            \
  91                 : : "r"(get_fs()) : )
  92
  93 #define __get_user(x, ptr)                               \
  94 ({                                                       \
  95         register long __gu_err __asm__ ("r8") = 0;       \
  96         register long __gu_val __asm__ ("r9") = 0;       \
  97                                                          \
  98         load_sr2();                                      \
  99         switch (sizeof(*(ptr))) {                        \
 100             case 1: __get_user_asm("ldb", ptr); break;   \
 101             case 2: __get_user_asm("ldh", ptr); break;   \
 102             case 4: __get_user_asm("ldw", ptr); break;   \
 103             case 8: LDD_USER(ptr);  break;               \
 104             default: BUILD_BUG(); break;                 \
 105         }                                                \
 106                                                          \
 107         (x) = (__force __typeof__(*(ptr))) __gu_val;     \
 108         __gu_err;                                        \
 109 })
 110
 111 #define __get_user_asm(ldx, ptr)                        \
 112         __asm__("\n1:\t" ldx "\t0(%%sr2,%2),%0\n\t"     \
 113                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_1)\
 114                 : "=r"(__gu_val), "=r"(__gu_err)        \
 115                 : "r"(ptr), "1"(__gu_err)               \
 116                 : "r1");
 117
 118 #if !defined(CONFIG_64BIT)
 119
 120 #define __get_user_asm64(ptr)                           \
 121         __asm__("\n1:\tldw 0(%%sr2,%2),%0"              \
 122                 "\n2:\tldw 4(%%sr2,%2),%R0\n\t"         \
 123                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_2)\
 124                 ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_get_user_skip_1)\
 125                 : "=r"(__gu_val), "=r"(__gu_err)        \
 126                 : "r"(ptr), "1"(__gu_err)               \
 127                 : "r1");
 128
 129 #endif /* !defined(CONFIG_64BIT) */
 130
 131
 132 #define __put_user(x, ptr)                                      \
 133 ({                                                              \
 134         register long __pu_err __asm__ ("r8") = 0;              \
 135         __typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x);       \
 136                                                                 \
 137         load_sr2();                                             \
 138         switch (sizeof(*(ptr))) {                               \
 139             case 1: __put_user_asm("stb", __x, ptr); break;     \
 140             case 2: __put_user_asm("sth", __x, ptr); break;     \
 141             case 4: __put_user_asm("stw", __x, ptr); break;     \
 142             case 8: STD_USER(__x, ptr); break;                  \
 143             default: BUILD_BUG(); break;                        \
 144         }                                                       \
 145                                                                 \
 146         __pu_err;                                               \
 147 })
 148
 149 /*
 150  * The "__put_user/kernel_asm()" macros tell gcc they read from memory
 151  * instead of writing. This is because they do not write to any memory
 152  * gcc knows about, so there are no aliasing issues. These macros must
 153  * also be aware that "fixup_put_user_skip_[12]" are executed in the
 154  * context of the fault, and any registers used there must be listed
 155  * as clobbers. In this case only "r1" is used by the current routines.
 156  * r8/r9 are already listed as err/val.
 157  */
 158
 159 #define __put_user_asm(stx, x, ptr)                         \
 160         __asm__ __volatile__ (                              \
 161                 "\n1:\t" stx "\t%2,0(%%sr2,%1)\n\t"         \
 162                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_1)\
 163                 : "=r"(__pu_err)                            \
 164                 : "r"(ptr), "r"(x), "0"(__pu_err)           \
 165                 : "r1")
 166
 167
 168 #if !defined(CONFIG_64BIT)
 169
 170 #define __put_user_asm64(__val, ptr) do {                   \
 171         __asm__ __volatile__ (                              \
 172                 "\n1:\tstw %2,0(%%sr2,%1)"                  \
 173                 "\n2:\tstw %R2,4(%%sr2,%1)\n\t"             \
 174                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_2)\
 175                 ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_put_user_skip_1)\
 176                 : "=r"(__pu_err)                            \
 177                 : "r"(ptr), "r"(__val), "0"(__pu_err) \
 178                 : "r1");                                    \
 179 } while (0)
 180
 181 #endif /* !defined(CONFIG_64BIT) */
 182
 183
 184 /*
 185  * Complex access routines -- external declarations
 186  */
 187
 188 extern unsigned long lcopy_to_user(void __user *, const void *, unsigned long);
 189 extern unsigned long lcopy_from_user(void *, const void __user *, unsigned long);
 190 extern unsigned long lcopy_in_user(void __user *, const void __user *, unsigned long);
 191 extern long strncpy_from_user(char *, const char __user *, long);
 192 extern unsigned lclear_user(void __user *, unsigned long);
 193 extern long lstrnlen_user(const char __user *, long);
 194 /*
 195  * Complex access routines -- macros
 196  */
 197 #define user_addr_max() (~0UL)
 198
 199 #define strnlen_user lstrnlen_user
 200 #define strlen_user(str) lstrnlen_user(str, 0x7fffffffL)
 201 #define clear_user lclear_user
 202 #define __clear_user lclear_user
 203
 204 unsigned long copy_to_user(void __user *dst, const void *src, unsigned long len);
 205 #define __copy_to_user copy_to_user
 206 unsigned long __copy_from_user(void *dst, const void __user *src, unsigned long len);
 207 unsigned long copy_in_user(void __user *dst, const void __user *src, unsigned long len);
 208 #define __copy_in_user copy_in_user
 209 #define __copy_to_user_inatomic __copy_to_user
 210 #define __copy_from_user_inatomic __copy_from_user
 211
 212 extern void __compiletime_error("usercopy buffer size is too small")
 213 __bad_copy_user(void);
 214
 215 static inline void copy_user_overflow(int size, unsigned long count)
 216 {
 217         WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
 218 }
 219
 220 static inline unsigned long __must_check copy_from_user(void *to,
 221                                           const void __user *from,
 222                                           unsigned long n)
 223 {
 224         int sz = __compiletime_object_size(to);
 225         unsigned long ret = n;
 226
 227         if (likely(sz == -1 || sz >= n))
 228                 ret = __copy_from_user(to, from, n);
 229         else if (!__builtin_constant_p(n))
 230                 copy_user_overflow(sz, n);
 231         else
 232                 __bad_copy_user();
 233
 234         if (unlikely(ret))
 235                 memset(to + (n - ret), 0, ret);
 236         return ret;
 237 }
 238
 239 struct pt_regs;
 240 int fixup_exception(struct pt_regs *regs);
 241
 242 #endif /* __PARISC_UACCESS_H */