sysdeps/unix/sysv/linux/aarch64/sysdep.h

   1 /* Copyright (C) 2005-2020 Free Software Foundation, Inc.
   2
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef _LINUX_AARCH64_SYSDEP_H
  20 #define _LINUX_AARCH64_SYSDEP_H 1
  21
  22 #include <sysdeps/unix/sysdep.h>
  23 #include <sysdeps/aarch64/sysdep.h>
  24 #include <sysdeps/unix/sysv/linux/generic/sysdep.h>
  25
  26 /* Defines RTLD_PRIVATE_ERRNO and USE_DL_SYSINFO.  */
  27 #include <dl-sysdep.h>
  28
  29 #include <tls.h>
  30
  31 /* In order to get __set_errno() definition in INLINE_SYSCALL.  */
  32 #ifndef __ASSEMBLER__
  33 #include <errno.h>
  34 #endif
  35
  36 /* For Linux we can use the system call table in the header file
  37         /usr/include/asm/unistd.h
  38    of the kernel.  But these symbols do not follow the SYS_* syntax
  39    so we have to redefine the `SYS_ify' macro here.  */
  40 #undef SYS_ify
  41 #define SYS_ify(syscall_name)   (__NR_##syscall_name)
  42
  43 #ifdef __ASSEMBLER__
  44
  45 /* Linux uses a negative return value to indicate syscall errors,
  46    unlike most Unices, which use the condition codes' carry flag.
  47
  48    Since version 2.1 the return value of a system call might be
  49    negative even if the call succeeded.  E.g., the `lseek' system call
  50    might return a large offset.  Therefore we must not anymore test
  51    for < 0, but test for a real error by making sure the value in R0
  52    is a real error number.  Linus said he will make sure the no syscall
  53    returns a value in -1 .. -4095 as a valid result so we can safely
  54    test with -4095.  */
  55
  56 # undef PSEUDO
  57 # define PSEUDO(name, syscall_name, args)                                     \
  58   .text;                                                                      \
  59   ENTRY (name);                                                               \
  60     DO_CALL (syscall_name, args);                                             \
  61     cmn x0, #4095;                                                            \
  62     b.cs .Lsyscall_error;
  63
  64 # undef PSEUDO_END
  65 # define PSEUDO_END(name)                                                     \
  66   SYSCALL_ERROR_HANDLER                                                       \
  67   END (name)
  68
  69 # undef PSEUDO_NOERRNO
  70 # define PSEUDO_NOERRNO(name, syscall_name, args)                             \
  71   .text;                                                                      \
  72   ENTRY (name);                                                               \
  73     DO_CALL (syscall_name, args);
  74
  75 # undef PSEUDO_END_NOERRNO
  76 # define PSEUDO_END_NOERRNO(name)                                             \
  77   END (name)
  78
  79 # define ret_NOERRNO ret
  80
  81 /* The function has to return the error code.  */
  82 # undef PSEUDO_ERRVAL
  83 # define PSEUDO_ERRVAL(name, syscall_name, args) \
  84   .text;                                                                      \
  85   ENTRY (name)                                                                \
  86     DO_CALL (syscall_name, args);                                             \
  87     neg x0, x0
  88
  89 # undef PSEUDO_END_ERRVAL
  90 # define PSEUDO_END_ERRVAL(name) \
  91   END (name)
  92
  93 # define ret_ERRVAL ret
  94
  95 # if !IS_IN (libc)
  96 #  define SYSCALL_ERROR  .Lsyscall_error
  97 #  if RTLD_PRIVATE_ERRNO
  98 #   define SYSCALL_ERROR_HANDLER                                \
  99 .Lsyscall_error:                                                \
 100         adrp    x1, C_SYMBOL_NAME(rtld_errno);                  \
 101         neg     w0, w0;                                         \
 102         str     w0, [x1, :lo12:C_SYMBOL_NAME(rtld_errno)];      \
 103         mov     x0, -1;                                         \
 104         RET;
 105 #  else
 106
 107 #   define SYSCALL_ERROR_HANDLER                                \
 108 .Lsyscall_error:                                                \
 109         adrp    x1, :gottprel:errno;                            \
 110         neg     w2, w0;                                         \
 111         ldr     PTR_REG(1), [x1, :gottprel_lo12:errno];         \
 112         mrs     x3, tpidr_el0;                                  \
 113         mov     x0, -1;                                         \
 114         str     w2, [x1, x3];                                   \
 115         RET;
 116 #  endif
 117 # else
 118 #  define SYSCALL_ERROR __syscall_error
 119 #  define SYSCALL_ERROR_HANDLER                                 \
 120 .Lsyscall_error:                                                \
 121         b       __syscall_error;
 122 # endif
 123
 124 /* Linux takes system call args in registers:
 125         syscall number  x8
 126         arg 1           x0
 127         arg 2           x1
 128         arg 3           x2
 129         arg 4           x3
 130         arg 5           x4
 131         arg 6           x5
 132         arg 7           x6
 133
 134    The compiler is going to form a call by coming here, through PSEUDO, with
 135    arguments
 136         syscall number  in the DO_CALL macro
 137         arg 1           x0
 138         arg 2           x1
 139         arg 3           x2
 140         arg 4           x3
 141         arg 5           x4
 142         arg 6           x5
 143         arg 7           x6
 144
 145 */
 146
 147 # undef DO_CALL
 148 # define DO_CALL(syscall_name, args)            \
 149     mov x8, SYS_ify (syscall_name);             \
 150     svc 0
 151
 152 #else /* not __ASSEMBLER__ */
 153
 154 # ifdef __LP64__
 155 #  define VDSO_NAME  "LINUX_2.6.39"
 156 #  define VDSO_HASH  123718537
 157 # else
 158 #  define VDSO_NAME  "LINUX_4.9"
 159 #  define VDSO_HASH  61765625
 160 # endif
 161
 162 /* List of system calls which are supported as vsyscalls.  */
 163 # define HAVE_CLOCK_GETRES_VSYSCALL     "__kernel_clock_getres"
 164 # define HAVE_CLOCK_GETTIME_VSYSCALL    "__kernel_clock_gettime"
 165 # define HAVE_GETTIMEOFDAY_VSYSCALL     "__kernel_gettimeofday"
 166
 167 /* Previously AArch64 used the generic version without the libc_hidden_def
 168    which lead in a non existent __send symbol in libc.so.  */
 169 # undef HAVE_INTERNAL_SEND_SYMBOL
 170
 171 # define SINGLE_THREAD_BY_GLOBAL                1
 172
 173 /* Define a macro which expands into the inline wrapper code for a system
 174    call.  */
 175 # undef INLINE_SYSCALL
 176 # define INLINE_SYSCALL(name, nr, args...)                              \
 177   ({ unsigned long _sys_result = INTERNAL_SYSCALL (name, , nr, args);   \
 178      if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_sys_result, ), 0))\
 179        {                                                                \
 180          __set_errno (INTERNAL_SYSCALL_ERRNO (_sys_result, ));          \
 181          _sys_result = (unsigned long) -1;                              \
 182        }                                                                \
 183      (long) _sys_result; })
 184
 185 # undef INTERNAL_SYSCALL_DECL
 186 # define INTERNAL_SYSCALL_DECL(err) do { } while (0)
 187
 188 # undef INTERNAL_SYSCALL_RAW
 189 # define INTERNAL_SYSCALL_RAW(name, err, nr, args...)           \
 190   ({ long _sys_result;                                          \
 191      {                                                          \
 192        LOAD_ARGS_##nr (args)                                    \
 193        register long _x8 asm ("x8") = (name);                   \
 194        asm volatile ("svc       0       // syscall " # name     \
 195                      : "=r" (_x0) : "r"(_x8) ASM_ARGS_##nr : "memory"); \
 196        _sys_result = _x0;                                       \
 197      }                                                          \
 198      _sys_result; })
 199
 200 # undef INTERNAL_SYSCALL
 201 # define INTERNAL_SYSCALL(name, err, nr, args...)               \
 202         INTERNAL_SYSCALL_RAW(SYS_ify(name), err, nr, args)
 203
 204 # undef INTERNAL_SYSCALL_AARCH64
 205 # define INTERNAL_SYSCALL_AARCH64(name, err, nr, args...)       \
 206         INTERNAL_SYSCALL_RAW(__ARM_NR_##name, err, nr, args)
 207
 208 # undef INTERNAL_SYSCALL_ERROR_P
 209 # define INTERNAL_SYSCALL_ERROR_P(val, err) \
 210   ((unsigned long) (val) >= (unsigned long) -4095)
 211
 212 # undef INTERNAL_SYSCALL_ERRNO
 213 # define INTERNAL_SYSCALL_ERRNO(val, err)       (-(val))
 214
 215 # define LOAD_ARGS_0()                          \
 216   register long _x0 asm ("x0");
 217 # define LOAD_ARGS_1(x0)                        \
 218   long _x0tmp = (long) (x0);                    \
 219   LOAD_ARGS_0 ()                                \
 220   _x0 = _x0tmp;
 221 # define LOAD_ARGS_2(x0, x1)                    \
 222   long _x1tmp = (long) (x1);                    \
 223   LOAD_ARGS_1 (x0)                              \
 224   register long _x1 asm ("x1") = _x1tmp;
 225 # define LOAD_ARGS_3(x0, x1, x2)                \
 226   long _x2tmp = (long) (x2);                    \
 227   LOAD_ARGS_2 (x0, x1)                          \
 228   register long _x2 asm ("x2") = _x2tmp;
 229 # define LOAD_ARGS_4(x0, x1, x2, x3)            \
 230   long _x3tmp = (long) (x3);                    \
 231   LOAD_ARGS_3 (x0, x1, x2)                      \
 232   register long _x3 asm ("x3") = _x3tmp;
 233 # define LOAD_ARGS_5(x0, x1, x2, x3, x4)        \
 234   long _x4tmp = (long) (x4);                    \
 235   LOAD_ARGS_4 (x0, x1, x2, x3)                  \
 236   register long _x4 asm ("x4") = _x4tmp;
 237 # define LOAD_ARGS_6(x0, x1, x2, x3, x4, x5)    \
 238   long _x5tmp = (long) (x5);                    \
 239   LOAD_ARGS_5 (x0, x1, x2, x3, x4)              \
 240   register long _x5 asm ("x5") = _x5tmp;
 241 # define LOAD_ARGS_7(x0, x1, x2, x3, x4, x5, x6)\
 242   long _x6tmp = (long) (x6);                    \
 243   LOAD_ARGS_6 (x0, x1, x2, x3, x4, x5)          \
 244   register long _x6 asm ("x6") = _x6tmp;
 245
 246 # define ASM_ARGS_0
 247 # define ASM_ARGS_1     , "r" (_x0)
 248 # define ASM_ARGS_2     ASM_ARGS_1, "r" (_x1)
 249 # define ASM_ARGS_3     ASM_ARGS_2, "r" (_x2)
 250 # define ASM_ARGS_4     ASM_ARGS_3, "r" (_x3)
 251 # define ASM_ARGS_5     ASM_ARGS_4, "r" (_x4)
 252 # define ASM_ARGS_6     ASM_ARGS_5, "r" (_x5)
 253 # define ASM_ARGS_7     ASM_ARGS_6, "r" (_x6)
 254
 255 # undef INTERNAL_SYSCALL_NCS
 256 # define INTERNAL_SYSCALL_NCS(number, err, nr, args...) \
 257         INTERNAL_SYSCALL_RAW (number, err, nr, args)
 258
 259 #endif  /* __ASSEMBLER__ */
 260
 261 /* Pointer mangling is supported for AArch64.  */
 262 #if (IS_IN (rtld) \
 263      || (!defined SHARED && (IS_IN (libc) \
 264                              || IS_IN (libpthread))))
 265 # ifdef __ASSEMBLER__
 266 /* Note, dst, src, guard, and tmp are all register numbers rather than
 267    register names so they will work with both ILP32 and LP64. */
 268 #  define PTR_MANGLE(dst, src, guard, tmp)                                \
 269   LDST_PCREL (ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard_local)); \
 270   PTR_MANGLE2 (dst, src, guard)
 271 /* Use PTR_MANGLE2 for efficiency if guard is already loaded.  */
 272 #  define PTR_MANGLE2(dst, src, guard)\
 273   eor x##dst, x##src, x##guard
 274 #  define PTR_DEMANGLE(dst, src, guard, tmp)\
 275   PTR_MANGLE (dst, src, guard, tmp)
 276 #  define PTR_DEMANGLE2(dst, src, guard)\
 277   PTR_MANGLE2 (dst, src, guard)
 278 # else
 279 extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
 280 #  define PTR_MANGLE(var) \
 281   (var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard_local)
 282 #  define PTR_DEMANGLE(var)     PTR_MANGLE (var)
 283 # endif
 284 #else
 285 # ifdef __ASSEMBLER__
 286 /* Note, dst, src, guard, and tmp are all register numbers rather than
 287    register names so they will work with both ILP32 and LP64. */
 288 #  define PTR_MANGLE(dst, src, guard, tmp)                             \
 289   LDST_GLOBAL (ldr, guard, tmp, C_SYMBOL_NAME(__pointer_chk_guard));   \
 290   PTR_MANGLE2 (dst, src, guard)
 291 /* Use PTR_MANGLE2 for efficiency if guard is already loaded.  */
 292 #  define PTR_MANGLE2(dst, src, guard)\
 293   eor x##dst, x##src, x##guard
 294 #  define PTR_DEMANGLE(dst, src, guard, tmp)\
 295   PTR_MANGLE (dst, src, guard, tmp)
 296 #  define PTR_DEMANGLE2(dst, src, guard)\
 297   PTR_MANGLE2 (dst, src, guard)
 298 # else
 299 extern uintptr_t __pointer_chk_guard attribute_relro;
 300 #  define PTR_MANGLE(var) \
 301   (var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard)
 302 #  define PTR_DEMANGLE(var) PTR_MANGLE (var)
 303 # endif
 304 #endif
 305
 306 #endif /* linux/aarch64/sysdep.h */