ports/sysdeps/unix/sysv/linux/m68k/sysdep.h

   1 /* Copyright (C) 1996, 1997, 1998, 2000, 2003, 2004, 2006, 2010, 2012
   2    Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Written by Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de>,
   5    December 1995.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library.  If not, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #include <tls.h>
  22
  23 /* Defines RTLD_PRIVATE_ERRNO.  */
  24 #include <dl-sysdep.h>
  25
  26 /* For Linux we can use the system call table in the header file
  27         /usr/include/asm/unistd.h
  28    of the kernel.  But these symbols do not follow the SYS_* syntax
  29    so we have to redefine the `SYS_ify' macro here.  */
  30 #undef SYS_ify
  31 #define SYS_ify(syscall_name)   __NR_##syscall_name
  32
  33 #ifdef __ASSEMBLER__
  34
  35 /* Linux uses a negative return value to indicate syscall errors, unlike
  36    most Unices, which use the condition codes' carry flag.
  37
  38    Since version 2.1 the return value of a system call might be negative
  39    even if the call succeeded.  E.g., the `lseek' system call might return
  40    a large offset.  Therefore we must not anymore test for < 0, but test
  41    for a real error by making sure the value in %d0 is a real error
  42    number.  Linus said he will make sure the no syscall returns a value
  43    in -1 .. -4095 as a valid result so we can savely test with -4095.  */
  44
  45 /* We don't want the label for the error handler to be visible in the symbol
  46    table when we define it here.  */
  47 #ifdef PIC
  48 #define SYSCALL_ERROR_LABEL .Lsyscall_error
  49 #else
  50 #define SYSCALL_ERROR_LABEL __syscall_error
  51 #endif
  52
  53 #undef PSEUDO
  54 #define PSEUDO(name, syscall_name, args)                                      \
  55   .text;                                                                      \
  56   ENTRY (name)                                                                \
  57     DO_CALL (syscall_name, args);                                             \
  58     cmp.l &-4095, %d0;                                                        \
  59     jcc SYSCALL_ERROR_LABEL
  60
  61 #undef PSEUDO_END
  62 #define PSEUDO_END(name)                                                      \
  63   SYSCALL_ERROR_HANDLER;                                                      \
  64   END (name)
  65
  66 #undef PSEUDO_NOERRNO
  67 #define PSEUDO_NOERRNO(name, syscall_name, args)                              \
  68   .text;                                                                      \
  69   ENTRY (name)                                                                \
  70     DO_CALL (syscall_name, args)
  71
  72 #undef PSEUDO_END_NOERRNO
  73 #define PSEUDO_END_NOERRNO(name)                                              \
  74   END (name)
  75
  76 #define ret_NOERRNO rts
  77
  78 /* The function has to return the error code.  */
  79 #undef  PSEUDO_ERRVAL
  80 #define PSEUDO_ERRVAL(name, syscall_name, args) \
  81   .text;                                                                      \
  82   ENTRY (name)                                                                \
  83     DO_CALL (syscall_name, args);                                             \
  84     negl %d0
  85
  86 #undef  PSEUDO_END_ERRVAL
  87 #define PSEUDO_END_ERRVAL(name) \
  88   END (name)
  89
  90 #define ret_ERRVAL rts
  91
  92 #ifdef PIC
  93 # if RTLD_PRIVATE_ERRNO
  94 #  define SYSCALL_ERROR_HANDLER                                               \
  95 SYSCALL_ERROR_LABEL:                                                          \
  96     PCREL_OP (lea, rtld_errno, %a0, %a0);                                     \
  97     neg.l %d0;                                                                \
  98     move.l %d0, (%a0);                                                        \
  99     move.l &-1, %d0;                                                          \
 100     /* Copy return value to %a0 for syscalls that are declared to return      \
 101        a pointer (e.g., mmap).  */                                            \
 102     move.l %d0, %a0;                                                          \
 103     rts;
 104 # elif defined _LIBC_REENTRANT
 105 #  ifndef NOT_IN_libc
 106 #   define SYSCALL_ERROR_ERRNO __libc_errno
 107 #  else
 108 #   define SYSCALL_ERROR_ERRNO errno
 109 #  endif
 110 #  define SYSCALL_ERROR_HANDLER                                               \
 111 SYSCALL_ERROR_LABEL:                                                          \
 112     neg.l %d0;                                                                \
 113     move.l %d0, -(%sp);                                                       \
 114     cfi_adjust_cfa_offset (4);                                                \
 115     jbsr __m68k_read_tp@PLTPC;                                                \
 116     SYSCALL_ERROR_LOAD_GOT (%a1);                                             \
 117     add.l (SYSCALL_ERROR_ERRNO@TLSIE, %a1), %a0;                              \
 118     move.l (%sp)+, (%a0);                                                     \
 119     cfi_adjust_cfa_offset (-4);                                               \
 120     move.l &-1, %d0;                                                          \
 121     /* Copy return value to %a0 for syscalls that are declared to return      \
 122        a pointer (e.g., mmap).  */                                            \
 123     move.l %d0, %a0;                                                          \
 124     rts;
 125 # else /* !_LIBC_REENTRANT */
 126 /* Store (- %d0) into errno through the GOT.  */
 127 #  define SYSCALL_ERROR_HANDLER                                               \
 128 SYSCALL_ERROR_LABEL:                                                          \
 129     move.l (errno@GOTPC, %pc), %a0;                                           \
 130     neg.l %d0;                                                                \
 131     move.l %d0, (%a0);                                                        \
 132     move.l &-1, %d0;                                                          \
 133     /* Copy return value to %a0 for syscalls that are declared to return      \
 134        a pointer (e.g., mmap).  */                                            \
 135     move.l %d0, %a0;                                                          \
 136     rts;
 137 # endif /* _LIBC_REENTRANT */
 138 #else
 139 # define SYSCALL_ERROR_HANDLER  /* Nothing here; code in sysdep.S is used.  */
 140 #endif /* PIC */
 141
 142 /* Linux takes system call arguments in registers:
 143
 144         syscall number  %d0          call-clobbered
 145         arg 1           %d1          call-clobbered
 146         arg 2           %d2          call-saved
 147         arg 3           %d3          call-saved
 148         arg 4           %d4          call-saved
 149         arg 5           %d5          call-saved
 150         arg 6           %a0          call-clobbered
 151
 152    The stack layout upon entering the function is:
 153
 154         24(%sp)         Arg# 6
 155         20(%sp)         Arg# 5
 156         16(%sp)         Arg# 4
 157         12(%sp)         Arg# 3
 158          8(%sp)         Arg# 2
 159          4(%sp)         Arg# 1
 160           (%sp)         Return address
 161
 162    (Of course a function with say 3 arguments does not have entries for
 163    arguments 4 and 5.)
 164
 165    Separate move's are faster than movem, but need more space.  Since
 166    speed is more important, we don't use movem.  Since %a0 and %a1 are
 167    scratch registers, we can use them for saving as well.  */
 168
 169 #define DO_CALL(syscall_name, args)                                           \
 170     move.l &SYS_ify(syscall_name), %d0;                                       \
 171     DOARGS_##args                                                             \
 172     trap &0;                                                                  \
 173     UNDOARGS_##args
 174
 175 #define DOARGS_0        /* No arguments to frob.  */
 176 #define UNDOARGS_0      /* No arguments to unfrob.  */
 177 #define _DOARGS_0(n)    /* No arguments to frob.  */
 178
 179 #define DOARGS_1        _DOARGS_1 (4)
 180 #define _DOARGS_1(n)    move.l n(%sp), %d1; _DOARGS_0 (n)
 181 #define UNDOARGS_1      UNDOARGS_0
 182
 183 #define DOARGS_2        _DOARGS_2 (8)
 184 #define _DOARGS_2(n)    move.l %d2, %a0; cfi_register (%d2, %a0);             \
 185                         move.l n(%sp), %d2; _DOARGS_1 (n-4)
 186 #define UNDOARGS_2      UNDOARGS_1; move.l %a0, %d2; cfi_restore (%d2)
 187
 188 #define DOARGS_3        _DOARGS_3 (12)
 189 #define _DOARGS_3(n)    move.l %d3, %a1; cfi_register (%d3, %a1);             \
 190                         move.l n(%sp), %d3; _DOARGS_2 (n-4)
 191 #define UNDOARGS_3      UNDOARGS_2; move.l %a1, %d3; cfi_restore (%d3)
 192
 193 #define DOARGS_4        _DOARGS_4 (16)
 194 #define _DOARGS_4(n)    move.l %d4, -(%sp);                                   \
 195                         cfi_adjust_cfa_offset (4); cfi_rel_offset (%d4, 0);   \
 196                         move.l n+4(%sp), %d4; _DOARGS_3 (n)
 197 #define UNDOARGS_4      UNDOARGS_3; move.l (%sp)+, %d4;                       \
 198                         cfi_adjust_cfa_offset (-4); cfi_restore (%d4)
 199
 200 #define DOARGS_5        _DOARGS_5 (20)
 201 #define _DOARGS_5(n)    move.l %d5, -(%sp);                                   \
 202                         cfi_adjust_cfa_offset (4); cfi_rel_offset (%d5, 0);   \
 203                         move.l n+4(%sp), %d5; _DOARGS_4 (n)
 204 #define UNDOARGS_5      UNDOARGS_4; move.l (%sp)+, %d5;                       \
 205                         cfi_adjust_cfa_offset (-4); cfi_restore (%d5)
 206
 207 #define DOARGS_6        _DOARGS_6 (24)
 208 #define _DOARGS_6(n)    _DOARGS_5 (n-4); move.l %a0, -(%sp);                  \
 209                         cfi_adjust_cfa_offset (4);                            \
 210                         move.l n+12(%sp), %a0;
 211 #define UNDOARGS_6      move.l (%sp)+, %a0; cfi_adjust_cfa_offset (-4);       \
 212                         UNDOARGS_5
 213
 214
 215 #define ret     rts
 216 #if 0 /* Not used by Linux */
 217 #define r0      %d0
 218 #define r1      %d1
 219 #define MOVE(x,y)       movel x , y
 220 #endif
 221
 222 #else /* not __ASSEMBLER__ */
 223
 224 /* Define a macro which expands into the inline wrapper code for a system
 225    call.  */
 226 #undef INLINE_SYSCALL
 227 #define INLINE_SYSCALL(name, nr, args...)                               \
 228   ({ unsigned int _sys_result = INTERNAL_SYSCALL (name, , nr, args);    \
 229      if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (_sys_result, ), 0))\
 230        {                                                                \
 231          __set_errno (INTERNAL_SYSCALL_ERRNO (_sys_result, ));          \
 232          _sys_result = (unsigned int) -1;                               \
 233        }                                                                \
 234      (int) _sys_result; })
 235
 236 #undef INTERNAL_SYSCALL_DECL
 237 #define INTERNAL_SYSCALL_DECL(err) do { } while (0)
 238
 239 /* Define a macro which expands inline into the wrapper code for a system
 240    call.  This use is for internal calls that do not need to handle errors
 241    normally.  It will never touch errno.  This returns just what the kernel
 242    gave back.  */
 243 #undef INTERNAL_SYSCALL
 244 #define INTERNAL_SYSCALL_NCS(name, err, nr, args...)    \
 245   ({ unsigned int _sys_result;                          \
 246      {                                                  \
 247        /* Load argument values in temporary variables
 248           to perform side effects like function calls
 249           before the call used registers are set.  */   \
 250        LOAD_ARGS_##nr (args)                            \
 251        LOAD_REGS_##nr                                   \
 252        register int _d0 asm ("%d0") = name;             \
 253        asm volatile ("trap #0"                          \
 254                      : "=d" (_d0)                       \
 255                      : "0" (_d0) ASM_ARGS_##nr          \
 256                      : "memory");                       \
 257        _sys_result = _d0;                               \
 258      }                                                  \
 259      (int) _sys_result; })
 260 #define INTERNAL_SYSCALL(name, err, nr, args...)        \
 261   INTERNAL_SYSCALL_NCS (__NR_##name, err, nr, ##args)
 262
 263 #undef INTERNAL_SYSCALL_ERROR_P
 264 #define INTERNAL_SYSCALL_ERROR_P(val, err)              \
 265   ((unsigned int) (val) >= -4095U)
 266
 267 #undef INTERNAL_SYSCALL_ERRNO
 268 #define INTERNAL_SYSCALL_ERRNO(val, err)        (-(val))
 269
 270 #define LOAD_ARGS_0()
 271 #define LOAD_REGS_0
 272 #define ASM_ARGS_0
 273 #define LOAD_ARGS_1(a1)                         \
 274   LOAD_ARGS_0 ()                                \
 275   int __arg1 = (int) (a1);
 276 #define LOAD_REGS_1                             \
 277   register int _d1 asm ("d1") = __arg1;         \
 278   LOAD_REGS_0
 279 #define ASM_ARGS_1      ASM_ARGS_0, "d" (_d1)
 280 #define LOAD_ARGS_2(a1, a2)                     \
 281   LOAD_ARGS_1 (a1)                              \
 282   int __arg2 = (int) (a2);
 283 #define LOAD_REGS_2                             \
 284   register int _d2 asm ("d2") = __arg2;         \
 285   LOAD_REGS_1
 286 #define ASM_ARGS_2      ASM_ARGS_1, "d" (_d2)
 287 #define LOAD_ARGS_3(a1, a2, a3)                 \
 288   LOAD_ARGS_2 (a1, a2)                          \
 289   int __arg3 = (int) (a3);
 290 #define LOAD_REGS_3                             \
 291   register int _d3 asm ("d3") = __arg3;         \
 292   LOAD_REGS_2
 293 #define ASM_ARGS_3      ASM_ARGS_2, "d" (_d3)
 294 #define LOAD_ARGS_4(a1, a2, a3, a4)             \
 295   LOAD_ARGS_3 (a1, a2, a3)                      \
 296   int __arg4 = (int) (a4);
 297 #define LOAD_REGS_4                             \
 298   register int _d4 asm ("d4") = __arg4;         \
 299   LOAD_REGS_3
 300 #define ASM_ARGS_4      ASM_ARGS_3, "d" (_d4)
 301 #define LOAD_ARGS_5(a1, a2, a3, a4, a5)         \
 302   LOAD_ARGS_4 (a1, a2, a3, a4)                  \
 303   int __arg5 = (int) (a5);
 304 #define LOAD_REGS_5                             \
 305   register int _d5 asm ("d5") = __arg5;         \
 306   LOAD_REGS_4
 307 #define ASM_ARGS_5      ASM_ARGS_4, "d" (_d5)
 308 #define LOAD_ARGS_6(a1, a2, a3, a4, a5, a6)     \
 309   LOAD_ARGS_5 (a1, a2, a3, a4, a5)              \
 310   int __arg6 = (int) (a6);
 311 #define LOAD_REGS_6                             \
 312   register int _a0 asm ("a0") = __arg6;         \
 313   LOAD_REGS_5
 314 #define ASM_ARGS_6      ASM_ARGS_5, "a" (_a0)
 315
 316 #endif /* not __ASSEMBLER__ */
 317
 318 /* Pointer mangling is not yet supported for M68K.  */
 319 #define PTR_MANGLE(var) (void) (var)
 320 #define PTR_DEMANGLE(var) (void) (var)
 321
 322 #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
 323 /* M68K needs system-supplied DSO to access TLS helpers
 324    even when statically linked.  */
 325 # define NEED_STATIC_SYSINFO_DSO 1
 326 #endif