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 #include <linux/thread_info.h>
  15
  16 #define VERIFY_READ 0
  17 #define VERIFY_WRITE 1
  18
  19 #define KERNEL_DS       ((mm_segment_t){0})
  20 #define USER_DS         ((mm_segment_t){1})
  21
  22 #define segment_eq(a, b) ((a).seg == (b).seg)
  23
  24 #define get_ds()        (KERNEL_DS)
  25 #define get_fs()        (current_thread_info()->addr_limit)
  26 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  27
  28 /*
  29  * Note that since kernel addresses are in a separate address space on
  30  * parisc, we don't need to do anything for access_ok().
  31  * We just let the page fault handler do the right thing. This also means
  32  * that put_user is the same as __put_user, etc.
  33  */
  34
  35 #define access_ok(type, uaddr, size) (1)
  36
  37 #define put_user __put_user
  38 #define get_user __get_user
  39
  40 #if !defined(CONFIG_64BIT)
  41 #define LDD_USER(ptr)           __get_user_asm64(ptr)
  42 #define STD_USER(x, ptr)        __put_user_asm64(x, ptr)
  43 #else
  44 #define LDD_USER(ptr)           __get_user_asm("ldd", ptr)
  45 #define STD_USER(x, ptr)        __put_user_asm("std", x, ptr)
  46 #endif
  47
  48 /*
  49  * The exception table contains two values: the first is the relative offset to
  50  * the address of the instruction that is allowed to fault, and the second is
  51  * the relative offset to the address of the fixup routine. Since relative
  52  * addresses are used, 32bit values are sufficient even on 64bit kernel.
  53  */
  54
  55 #define ARCH_HAS_RELATIVE_EXTABLE
  56 struct exception_table_entry {
  57         int insn;       /* relative address of insn that is allowed to fault. */
  58         int fixup;      /* relative address of fixup routine */
  59 };
  60
  61 #define ASM_EXCEPTIONTABLE_ENTRY( fault_addr, except_addr )\
  62         ".section __ex_table,\"aw\"\n"                     \
  63         ".word (" #fault_addr " - .), (" #except_addr " - .)\n\t" \
  64         ".previous\n"
  65
  66 /*
  67  * The page fault handler stores, in a per-cpu area, the following information
  68  * if a fixup routine is available.
  69  */
  70 struct exception_data {
  71         unsigned long fault_ip;
  72         unsigned long fault_gp;
  73         unsigned long fault_space;
  74         unsigned long fault_addr;
  75 };
  76
  77 /*
  78  * load_sr2() preloads the space register %%sr2 - based on the value of
  79  * get_fs() - with either a value of 0 to access kernel space (KERNEL_DS which
  80  * is 0), or with the current value of %%sr3 to access user space (USER_DS)
  81  * memory. The following __get_user_asm() and __put_user_asm() functions have
  82  * %%sr2 hard-coded to access the requested memory.
  83  */
  84 #define load_sr2() \
  85         __asm__(" or,=  %0,%%r0,%%r0\n\t"       \
  86                 " mfsp %%sr3,%0\n\t"            \
  87                 " mtsp %0,%%sr2\n\t"            \
  88                 : : "r"(get_fs()) : )
  89
  90 #define __get_user(x, ptr)                               \
  91 ({                                                       \
  92         register long __gu_err __asm__ ("r8") = 0;       \
  93         register long __gu_val __asm__ ("r9") = 0;       \
  94                                                          \
  95         load_sr2();                                      \
  96         switch (sizeof(*(ptr))) {                        \
  97             case 1: __get_user_asm("ldb", ptr); break;   \
  98             case 2: __get_user_asm("ldh", ptr); break;   \
  99             case 4: __get_user_asm("ldw", ptr); break;   \
 100             case 8: LDD_USER(ptr);  break;               \
 101             default: BUILD_BUG(); break;                 \
 102         }                                                \
 103                                                          \
 104         (x) = (__force __typeof__(*(ptr))) __gu_val;     \
 105         __gu_err;                                        \
 106 })
 107
 108 #define __get_user_asm(ldx, ptr)                        \
 109         __asm__("\n1:\t" ldx "\t0(%%sr2,%2),%0\n\t"     \
 110                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_1)\
 111                 : "=r"(__gu_val), "=r"(__gu_err)        \
 112                 : "r"(ptr), "1"(__gu_err)               \
 113                 : "r1");
 114
 115 #if !defined(CONFIG_64BIT)
 116
 117 #define __get_user_asm64(ptr)                           \
 118         __asm__("\n1:\tldw 0(%%sr2,%2),%0"              \
 119                 "\n2:\tldw 4(%%sr2,%2),%R0\n\t"         \
 120                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_2)\
 121                 ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_get_user_skip_1)\
 122                 : "=r"(__gu_val), "=r"(__gu_err)        \
 123                 : "r"(ptr), "1"(__gu_err)               \
 124                 : "r1");
 125
 126 #endif /* !defined(CONFIG_64BIT) */
 127
 128
 129 #define __put_user(x, ptr)                                      \
 130 ({                                                              \
 131         register long __pu_err __asm__ ("r8") = 0;              \
 132         __typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x);       \
 133                                                                 \
 134         load_sr2();                                             \
 135         switch (sizeof(*(ptr))) {                               \
 136             case 1: __put_user_asm("stb", __x, ptr); break;     \
 137             case 2: __put_user_asm("sth", __x, ptr); break;     \
 138             case 4: __put_user_asm("stw", __x, ptr); break;     \
 139             case 8: STD_USER(__x, ptr); break;                  \
 140             default: BUILD_BUG(); break;                        \
 141         }                                                       \
 142                                                                 \
 143         __pu_err;                                               \
 144 })
 145
 146 /*
 147  * The "__put_user/kernel_asm()" macros tell gcc they read from memory
 148  * instead of writing. This is because they do not write to any memory
 149  * gcc knows about, so there are no aliasing issues. These macros must
 150  * also be aware that "fixup_put_user_skip_[12]" are executed in the
 151  * context of the fault, and any registers used there must be listed
 152  * as clobbers. In this case only "r1" is used by the current routines.
 153  * r8/r9 are already listed as err/val.
 154  */
 155
 156 #define __put_user_asm(stx, x, ptr)                         \
 157         __asm__ __volatile__ (                              \
 158                 "\n1:\t" stx "\t%2,0(%%sr2,%1)\n\t"         \
 159                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_1)\
 160                 : "=r"(__pu_err)                            \
 161                 : "r"(ptr), "r"(x), "0"(__pu_err)           \
 162                 : "r1")
 163
 164
 165 #if !defined(CONFIG_64BIT)
 166
 167 #define __put_user_asm64(__val, ptr) do {                   \
 168         __asm__ __volatile__ (                              \
 169                 "\n1:\tstw %2,0(%%sr2,%1)"                  \
 170                 "\n2:\tstw %R2,4(%%sr2,%1)\n\t"             \
 171                 ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_2)\
 172                 ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_put_user_skip_1)\
 173                 : "=r"(__pu_err)                            \
 174                 : "r"(ptr), "r"(__val), "0"(__pu_err) \
 175                 : "r1");                                    \
 176 } while (0)
 177
 178 #endif /* !defined(CONFIG_64BIT) */
 179
 180
 181 /*
 182  * Complex access routines -- external declarations
 183  */
 184
 185 extern unsigned long lcopy_to_user(void __user *, const void *, unsigned long);
 186 extern unsigned long lcopy_from_user(void *, const void __user *, unsigned long);
 187 extern unsigned long lcopy_in_user(void __user *, const void __user *, unsigned long);
 188 extern long strncpy_from_user(char *, const char __user *, long);
 189 extern unsigned lclear_user(void __user *, unsigned long);
 190 extern long lstrnlen_user(const char __user *, long);
 191 /*
 192  * Complex access routines -- macros
 193  */
 194 #define user_addr_max() (~0UL)
 195
 196 #define strnlen_user lstrnlen_user
 197 #define strlen_user(str) lstrnlen_user(str, 0x7fffffffL)
 198 #define clear_user lclear_user
 199 #define __clear_user lclear_user
 200
 201 unsigned long __must_check __copy_to_user(void __user *dst, const void *src,
 202                                           unsigned long len);
 203 unsigned long __must_check __copy_from_user(void *dst, const void __user *src,
 204                                           unsigned long len);
 205 unsigned long copy_in_user(void __user *dst, const void __user *src,
 206                            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 __compiletime_error("usercopy buffer size is too small")
 212 __bad_copy_user(void);
 213
 214 static inline void copy_user_overflow(int size, unsigned long count)
 215 {
 216         WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
 217 }
 218
 219 static __always_inline unsigned long __must_check
 220 copy_from_user(void *to, const void __user *from, unsigned long n)
 221 {
 222         int sz = __compiletime_object_size(to);
 223         unsigned long ret = n;
 224
 225         if (likely(sz < 0 || sz >= n)) {
 226                 check_object_size(to, n, false);
 227                 ret = __copy_from_user(to, from, n);
 228         } else if (!__builtin_constant_p(n))
 229                 copy_user_overflow(sz, n);
 230         else
 231                 __bad_copy_user();
 232
 233         if (unlikely(ret))
 234                 memset(to + (n - ret), 0, ret);
 235
 236         return ret;
 237 }
 238
 239 static __always_inline unsigned long __must_check
 240 copy_to_user(void __user *to, const void *from, unsigned long n)
 241 {
 242         int sz = __compiletime_object_size(from);
 243
 244         if (likely(sz < 0 || sz >= n)) {
 245                 check_object_size(from, n, true);
 246                 n = __copy_to_user(to, from, n);
 247         } else if (!__builtin_constant_p(n))
 248                 copy_user_overflow(sz, n);
 249         else
 250                 __bad_copy_user();
 251
 252         return n;
 253 }
 254
 255 struct pt_regs;
 256 int fixup_exception(struct pt_regs *regs);
 257
 258 #endif /* __PARISC_UACCESS_H */