libffi/src/arm/ffi.c

   1 /* -----------------------------------------------------------------------
   2    ffi.c - Copyright (c) 1998  Red Hat, Inc.
   3
   4    ARM Foreign Function Interface
   5
   6    Permission is hereby granted, free of charge, to any person obtaining
   7    a copy of this software and associated documentation files (the
   8    ``Software''), to deal in the Software without restriction, including
   9    without limitation the rights to use, copy, modify, merge, publish,
  10    distribute, sublicense, and/or sell copies of the Software, and to
  11    permit persons to whom the Software is furnished to do so, subject to
  12    the following conditions:
  13
  14    The above copyright notice and this permission notice shall be included
  15    in all copies or substantial portions of the Software.
  16
  17    THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18    OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  20    IN NO EVENT SHALL CYGNUS SOLUTIONS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21    OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22    ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23    OTHER DEALINGS IN THE SOFTWARE.
  24    ----------------------------------------------------------------------- */
  25
  26 #include <ffi.h>
  27 #include <ffi_common.h>
  28
  29 #include <stdlib.h>
  30
  31 /* ffi_prep_args is called by the assembly routine once stack space
  32    has been allocated for the function's arguments */
  33
  34 void ffi_prep_args(char *stack, extended_cif *ecif)
  35 {
  36   register unsigned int i;
  37   register void **p_argv;
  38   register char *argp;
  39   register ffi_type **p_arg;
  40
  41   argp = stack;
  42
  43   if ( ecif->cif->flags == FFI_TYPE_STRUCT ) {
  44     *(void **) argp = ecif->rvalue;
  45     argp += 4;
  46   }
  47
  48   p_argv = ecif->avalue;
  49
  50   for (i = ecif->cif->nargs, p_arg = ecif->cif->arg_types;
  51        (i != 0);
  52        i--, p_arg++)
  53     {
  54       size_t z;
  55
  56       /* Align if necessary */
  57       if (((*p_arg)->alignment - 1) & (unsigned) argp) {
  58         argp = (char *) ALIGN(argp, (*p_arg)->alignment);
  59       }
  60
  61       if ((*p_arg)->type == FFI_TYPE_STRUCT)
  62         argp = (char *) ALIGN(argp, 4);
  63
  64           z = (*p_arg)->size;
  65           if (z < sizeof(int))
  66             {
  67               z = sizeof(int);
  68               switch ((*p_arg)->type)
  69                 {
  70                 case FFI_TYPE_SINT8:
  71                   *(signed int *) argp = (signed int)*(SINT8 *)(* p_argv);
  72                   break;
  73
  74                 case FFI_TYPE_UINT8:
  75                   *(unsigned int *) argp = (unsigned int)*(UINT8 *)(* p_argv);
  76                   break;
  77
  78                 case FFI_TYPE_SINT16:
  79                   *(signed int *) argp = (signed int)*(SINT16 *)(* p_argv);
  80                   break;
  81
  82                 case FFI_TYPE_UINT16:
  83                   *(unsigned int *) argp = (unsigned int)*(UINT16 *)(* p_argv);
  84                   break;
  85
  86                 case FFI_TYPE_STRUCT:
  87                   memcpy(argp, *p_argv, (*p_arg)->size);
  88                   break;
  89
  90                 default:
  91                   FFI_ASSERT(0);
  92                 }
  93             }
  94           else if (z == sizeof(int))
  95             {
  96               *(unsigned int *) argp = (unsigned int)*(UINT32 *)(* p_argv);
  97             }
  98           else
  99             {
 100               memcpy(argp, *p_argv, z);
 101             }
 102           p_argv++;
 103           argp += z;
 104     }
 105
 106   return;
 107 }
 108
 109 /* Perform machine dependent cif processing */
 110 ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
 111 {
 112   /* Round the stack up to a multiple of 8 bytes.  This isn't needed
 113      everywhere, but it is on some platforms, and it doesn't harm anything
 114      when it isn't needed.  */
 115   cif->bytes = (cif->bytes + 7) & ~7;
 116
 117   /* Set the return type flag */
 118   switch (cif->rtype->type)
 119     {
 120     case FFI_TYPE_VOID:
 121     case FFI_TYPE_FLOAT:
 122     case FFI_TYPE_DOUBLE:
 123       cif->flags = (unsigned) cif->rtype->type;
 124       break;
 125
 126     case FFI_TYPE_SINT64:
 127     case FFI_TYPE_UINT64:
 128       cif->flags = (unsigned) FFI_TYPE_SINT64;
 129       break;
 130
 131     case FFI_TYPE_STRUCT:
 132       if (cif->rtype->size <= 4)
 133         /* A Composite Type not larger than 4 bytes is returned in r0.  */
 134         cif->flags = (unsigned)FFI_TYPE_INT;
 135       else
 136         /* A Composite Type larger than 4 bytes, or whose size cannot
 137            be determined statically ... is stored in memory at an
 138            address passed [in r0].  */
 139         cif->flags = (unsigned)FFI_TYPE_STRUCT;
 140       break;
 141
 142     default:
 143       cif->flags = FFI_TYPE_INT;
 144       break;
 145     }
 146
 147   return FFI_OK;
 148 }
 149
 150 extern void ffi_call_SYSV(void (*)(char *, extended_cif *), extended_cif *,
 151                           unsigned, unsigned, unsigned *, void (*fn)());
 152
 153 void ffi_call(ffi_cif *cif, void (*fn)(), void *rvalue, void **avalue)
 154 {
 155   extended_cif ecif;
 156
 157   int small_struct = (cif->flags == FFI_TYPE_INT
 158                       && cif->rtype->type == FFI_TYPE_STRUCT);
 159
 160   ecif.cif = cif;
 161   ecif.avalue = avalue;
 162
 163   unsigned int temp;
 164
 165   /* If the return value is a struct and we don't have a return */
 166   /* value address then we need to make one                     */
 167
 168   if ((rvalue == NULL) &&
 169       (cif->flags == FFI_TYPE_STRUCT))
 170     {
 171       ecif.rvalue = alloca(cif->rtype->size);
 172     }
 173   else if (small_struct)
 174     ecif.rvalue = &temp;
 175   else
 176     ecif.rvalue = rvalue;
 177
 178   switch (cif->abi)
 179     {
 180     case FFI_SYSV:
 181       ffi_call_SYSV(ffi_prep_args, &ecif, cif->bytes, cif->flags, ecif.rvalue,
 182                     fn);
 183
 184       break;
 185     default:
 186       FFI_ASSERT(0);
 187       break;
 188     }
 189   if (small_struct)
 190     memcpy (rvalue, &temp, cif->rtype->size);
 191 }
 192
 193 /** private members **/
 194
 195 static void ffi_prep_incoming_args_SYSV (char *stack, void **ret,
 196                                          void** args, ffi_cif* cif);
 197
 198 void ffi_closure_SYSV (ffi_closure *);
 199
 200 /* This function is jumped to by the trampoline */
 201
 202 unsigned int
 203 ffi_closure_SYSV_inner (closure, respp, args)
 204      ffi_closure *closure;
 205      void **respp;
 206      void *args;
 207 {
 208   // our various things...
 209   ffi_cif       *cif;
 210   void         **arg_area;
 211
 212   cif         = closure->cif;
 213   arg_area    = (void**) alloca (cif->nargs * sizeof (void*));
 214
 215   /* this call will initialize ARG_AREA, such that each
 216    * element in that array points to the corresponding
 217    * value on the stack; and if the function returns
 218    * a structure, it will re-set RESP to point to the
 219    * structure return address.  */
 220
 221   ffi_prep_incoming_args_SYSV(args, respp, arg_area, cif);
 222
 223   (closure->fun) (cif, *respp, arg_area, closure->user_data);
 224
 225   return cif->flags;
 226 }
 227
 228 /*@-exportheader@*/
 229 static void
 230 ffi_prep_incoming_args_SYSV(char *stack, void **rvalue,
 231                             void **avalue, ffi_cif *cif)
 232 /*@=exportheader@*/
 233 {
 234   register unsigned int i;
 235   register void **p_argv;
 236   register char *argp;
 237   register ffi_type **p_arg;
 238
 239   argp = stack;
 240
 241   if ( cif->flags == FFI_TYPE_STRUCT ) {
 242     *rvalue = *(void **) argp;
 243     argp += 4;
 244   }
 245
 246   p_argv = avalue;
 247
 248   for (i = cif->nargs, p_arg = cif->arg_types; (i != 0); i--, p_arg++)
 249     {
 250       size_t z;
 251
 252       size_t alignment = (*p_arg)->alignment;
 253       if (alignment < 4)
 254         alignment = 4;
 255       /* Align if necessary */
 256       if ((alignment - 1) & (unsigned) argp) {
 257         argp = (char *) ALIGN(argp, alignment);
 258       }
 259
 260       z = (*p_arg)->size;
 261
 262       /* because we're little endian, this is what it turns into.   */
 263
 264       *p_argv = (void*) argp;
 265
 266       p_argv++;
 267       argp += z;
 268     }
 269
 270   return;
 271 }
 272
 273 /* How to make a trampoline.  */
 274
 275 #define FFI_INIT_TRAMPOLINE(TRAMP,FUN,CTX)                              \
 276 ({ unsigned char *__tramp = (unsigned char*)(TRAMP);                    \
 277    unsigned int  __fun = (unsigned int)(FUN);                           \
 278    unsigned int  __ctx = (unsigned int)(CTX);                           \
 279    *(unsigned int*) &__tramp[0] = 0xe92d000f; /* stmfd sp!, {r0-r3} */  \
 280    *(unsigned int*) &__tramp[4] = 0xe59f0000; /* ldr r0, [pc] */        \
 281    *(unsigned int*) &__tramp[8] = 0xe59ff000; /* ldr pc, [pc] */        \
 282    *(unsigned int*) &__tramp[12] = __ctx;                               \
 283    *(unsigned int*) &__tramp[16] = __fun;                               \
 284    __clear_cache((&__tramp[0]), (&__tramp[19]));                        \
 285  })
 286
 287
 288 /* the cif must already be prep'ed */
 289
 290 ffi_status
 291 ffi_prep_closure_loc (ffi_closure* closure,
 292                       ffi_cif* cif,
 293                       void (*fun)(ffi_cif*,void*,void**,void*),
 294                       void *user_data,
 295                       void *codeloc)
 296 {
 297   FFI_ASSERT (cif->abi == FFI_SYSV);
 298
 299   FFI_INIT_TRAMPOLINE (&closure->tramp[0], \
 300                        &ffi_closure_SYSV,  \
 301                        codeloc);
 302
 303   closure->cif  = cif;
 304   closure->user_data = user_data;
 305   closure->fun  = fun;
 306
 307   return FFI_OK;
 308 }