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_KERNEL(ptr)         BUILD_BUG()
  44 #define LDD_USER(ptr)           BUILD_BUG()
  45 #define STD_KERNEL(x, ptr)      __put_kernel_asm64(x, ptr)
  46 #define STD_USER(x, ptr)        __put_user_asm64(x, ptr)
  47 #else
  48 #define LDD_KERNEL(ptr)         __get_kernel_asm("ldd", ptr)
  49 #define LDD_USER(ptr)           __get_user_asm("ldd", ptr)
  50 #define STD_KERNEL(x, ptr)      __put_kernel_asm("std", x, ptr)
  51 #define STD_USER(x, ptr)        __put_user_asm("std", x, ptr)
  52 #endif
  53
  54 /*
  55  * The exception table contains two values: the first is the relative offset to
  56  * the address of the instruction that is allowed to fault, and the second is
  57  * the relative offset to the address of the fixup routine. Since relative
  58  * addresses are used, 32bit values are sufficient even on 64bit kernel.
  59  */
  60
  61 #define ARCH_HAS_RELATIVE_EXTABLE
  62 struct exception_table_entry {
  63         int insn;       /* relative address of insn that is allowed to fault. */
  64         int fixup;      /* relative address of fixup routine */
  65 };
  66
  67 #define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\
  68         ".section __ex_table,\"aw\"\n"                     \
  69         ".word (" #fault_addr " - .), (" #except_addr " - .)\n\t" \
  70         ".previous\n"
  71
  72 /*
  73  * The page fault handler stores, in a per-cpu area, the following information
  74  * if a fixup routine is available.
  75  */
  76 struct exception_data {
  77         unsigned long fault_ip;
  78         unsigned long fault_gp;
  79         unsigned long fault_space;
  80         unsigned long fault_addr;
  81 };
  82
  83 #define __get_user(x, ptr)                               \
  84 ({                                                       \
  85         register long __gu_err __asm__ ("r8") = 0;       \
  86         register long __gu_val __asm__ ("r9") = 0;       \
  87                                                          \
  88         if (segment_eq(get_fs(), KERNEL_DS)) {           \
  89             switch (sizeof(*(ptr))) {                    \
  90             case 1: __get_kernel_asm("ldb", ptr); break; \
  91             case 2: __get_kernel_asm("ldh", ptr); break; \
  92             case 4: __get_kernel_asm("ldw", ptr); break; \
  93             case 8: LDD_KERNEL(ptr); break;              \
  94             default: BUILD_BUG(); break;                 \
  95             }                                            \
  96         }                                                \
  97         else {                                           \
  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                                                          \
 107         (x) = (__force __typeof__(*(ptr))) __gu_val;     \
 108         __gu_err;                                        \
 109 })
 110
 111 #define __get_kernel_asm(ldx, ptr)                      \
 112         __asm__("\n1:\t" ldx "\t0(%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 #define __get_user_asm(ldx, ptr)                        \
 119         __asm__("\n1:\t" ldx "\t0(%%sr3,%2),%0\n\t"     \
 120                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_1)\
 121                 : "=r"(__gu_val), "=r"(__gu_err)        \
 122                 : "r"(ptr), "1"(__gu_err)               \
 123                 : "r1");
 124
 125 #define __put_user(x, ptr)                                      \
 126 ({                                                              \
 127         register long __pu_err __asm__ ("r8") = 0;              \
 128         __typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x);       \
 129                                                                 \
 130         if (segment_eq(get_fs(), KERNEL_DS)) {                  \
 131             switch (sizeof(*(ptr))) {                           \
 132             case 1: __put_kernel_asm("stb", __x, ptr); break;   \
 133             case 2: __put_kernel_asm("sth", __x, ptr); break;   \
 134             case 4: __put_kernel_asm("stw", __x, ptr); break;   \
 135             case 8: STD_KERNEL(__x, ptr); break;                \
 136             default: BUILD_BUG(); break;                        \
 137             }                                                   \
 138         }                                                       \
 139         else {                                                  \
 140             switch (sizeof(*(ptr))) {                           \
 141             case 1: __put_user_asm("stb", __x, ptr); break;     \
 142             case 2: __put_user_asm("sth", __x, ptr); break;     \
 143             case 4: __put_user_asm("stw", __x, ptr); break;     \
 144             case 8: STD_USER(__x, ptr); break;                  \
 145             default: BUILD_BUG(); break;                        \
 146             }                                                   \
 147         }                                                       \
 148                                                                 \
 149         __pu_err;                                               \
 150 })
 151
 152 /*
 153  * The "__put_user/kernel_asm()" macros tell gcc they read from memory
 154  * instead of writing. This is because they do not write to any memory
 155  * gcc knows about, so there are no aliasing issues. These macros must
 156  * also be aware that "fixup_put_user_skip_[12]" are executed in the
 157  * context of the fault, and any registers used there must be listed
 158  * as clobbers. In this case only "r1" is used by the current routines.
 159  * r8/r9 are already listed as err/val.
 160  */
 161
 162 #define __put_kernel_asm(stx, x, ptr)                       \
 163         __asm__ __volatile__ (                              \
 164                 "\n1:\t" stx "\t%2,0(%1)\n\t"               \
 165                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_1)\
 166                 : "=r"(__pu_err)                            \
 167                 : "r"(ptr), "r"(x), "0"(__pu_err)           \
 168                 : "r1")
 169
 170 #define __put_user_asm(stx, x, ptr)                         \
 171         __asm__ __volatile__ (                              \
 172                 "\n1:\t" stx "\t%2,0(%%sr3,%1)\n\t"         \
 173                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_1)\
 174                 : "=r"(__pu_err)                            \
 175                 : "r"(ptr), "r"(x), "0"(__pu_err)           \
 176                 : "r1")
 177
 178
 179 #if !defined(CONFIG_64BIT)
 180
 181 #define __put_kernel_asm64(__val, ptr) do {                 \
 182         __asm__ __volatile__ (                              \
 183                 "\n1:\tstw %2,0(%1)"                        \
 184                 "\n2:\tstw %R2,4(%1)\n\t"                   \
 185                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_2)\
 186                 ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_put_user_skip_1)\
 187                 : "=r"(__pu_err)                            \
 188                 : "r"(ptr), "r"(__val), "0"(__pu_err) \
 189                 : "r1");                                    \
 190 } while (0)
 191
 192 #define __put_user_asm64(__val, ptr) do {                   \
 193         __asm__ __volatile__ (                              \
 194                 "\n1:\tstw %2,0(%%sr3,%1)"                  \
 195                 "\n2:\tstw %R2,4(%%sr3,%1)\n\t"             \
 196                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_2)\
 197                 ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_put_user_skip_1)\
 198                 : "=r"(__pu_err)                            \
 199                 : "r"(ptr), "r"(__val), "0"(__pu_err) \
 200                 : "r1");                                    \
 201 } while (0)
 202
 203 #endif /* !defined(CONFIG_64BIT) */
 204
 205
 206 /*
 207  * Complex access routines -- external declarations
 208  */
 209
 210 extern unsigned long lcopy_to_user(void __user *, const void *, unsigned long);
 211 extern unsigned long lcopy_from_user(void *, const void __user *, unsigned long);
 212 extern unsigned long lcopy_in_user(void __user *, const void __user *, unsigned long);
 213 extern long strncpy_from_user(char *, const char __user *, long);
 214 extern unsigned lclear_user(void __user *, unsigned long);
 215 extern long lstrnlen_user(const char __user *, long);
 216 /*
 217  * Complex access routines -- macros
 218  */
 219 #define user_addr_max() (~0UL)
 220
 221 #define strnlen_user lstrnlen_user
 222 #define strlen_user(str) lstrnlen_user(str, 0x7fffffffL)
 223 #define clear_user lclear_user
 224 #define __clear_user lclear_user
 225
 226 unsigned long copy_to_user(void __user *dst, const void *src, unsigned long len);
 227 #define __copy_to_user copy_to_user
 228 unsigned long __copy_from_user(void *dst, const void __user *src, unsigned long len);
 229 unsigned long copy_in_user(void __user *dst, const void __user *src, unsigned long len);
 230 #define __copy_in_user copy_in_user
 231 #define __copy_to_user_inatomic __copy_to_user
 232 #define __copy_from_user_inatomic __copy_from_user
 233
 234 extern void copy_from_user_overflow(void)
 235 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 236         __compiletime_error("copy_from_user() buffer size is not provably correct")
 237 #else
 238         __compiletime_warning("copy_from_user() buffer size is not provably correct")
 239 #endif
 240 ;
 241
 242 static inline unsigned long __must_check copy_from_user(void *to,
 243                                           const void __user *from,
 244                                           unsigned long n)
 245 {
 246         int sz = __compiletime_object_size(to);
 247         int ret = -EFAULT;
 248
 249         if (likely(sz == -1 || !__builtin_constant_p(n) || sz >= n))
 250                 ret = __copy_from_user(to, from, n);
 251         else
 252                 copy_from_user_overflow();
 253
 254         return ret;
 255 }
 256
 257 struct pt_regs;
 258 int fixup_exception(struct pt_regs *regs);
 259
 260 #endif /* __PARISC_UACCESS_H */