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,
  18    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  19    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20    NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  21    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  22    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24    DEALINGS IN THE SOFTWARE.
  25    ----------------------------------------------------------------------- */
  26
  27 #include <ffi.h>
  28 #include <ffi_common.h>
  29
  30 #include <stdlib.h>
  31
  32 /* ffi_prep_args is called by the assembly routine once stack space
  33    has been allocated for the function's arguments */
  34
  35 void ffi_prep_args(char *stack, extended_cif *ecif)
  36 {
  37   register unsigned int i;
  38   register void **p_argv;
  39   register char *argp;
  40   register ffi_type **p_arg;
  41
  42   argp = stack;
  43
  44   if ( ecif->cif->flags == FFI_TYPE_STRUCT ) {
  45     *(void **) argp = ecif->rvalue;
  46     argp += 4;
  47   }
  48
  49   p_argv = ecif->avalue;
  50
  51   for (i = ecif->cif->nargs, p_arg = ecif->cif->arg_types;
  52        (i != 0);
  53        i--, p_arg++)
  54     {
  55       size_t z;
  56
  57       /* Align if necessary */
  58       if (((*p_arg)->alignment - 1) & (unsigned) argp) {
  59         argp = (char *) ALIGN(argp, (*p_arg)->alignment);
  60       }
  61
  62       if ((*p_arg)->type == FFI_TYPE_STRUCT)
  63         argp = (char *) ALIGN(argp, 4);
  64
  65           z = (*p_arg)->size;
  66           if (z < sizeof(int))
  67             {
  68               z = sizeof(int);
  69               switch ((*p_arg)->type)
  70                 {
  71                 case FFI_TYPE_SINT8:
  72                   *(signed int *) argp = (signed int)*(SINT8 *)(* p_argv);
  73                   break;
  74
  75                 case FFI_TYPE_UINT8:
  76                   *(unsigned int *) argp = (unsigned int)*(UINT8 *)(* p_argv);
  77                   break;
  78
  79                 case FFI_TYPE_SINT16:
  80                   *(signed int *) argp = (signed int)*(SINT16 *)(* p_argv);
  81                   break;
  82
  83                 case FFI_TYPE_UINT16:
  84                   *(unsigned int *) argp = (unsigned int)*(UINT16 *)(* p_argv);
  85                   break;
  86
  87                 case FFI_TYPE_STRUCT:
  88                   memcpy(argp, *p_argv, (*p_arg)->size);
  89                   break;
  90
  91                 default:
  92                   FFI_ASSERT(0);
  93                 }
  94             }
  95           else if (z == sizeof(int))
  96             {
  97               *(unsigned int *) argp = (unsigned int)*(UINT32 *)(* p_argv);
  98             }
  99           else
 100             {
 101               memcpy(argp, *p_argv, z);
 102             }
 103           p_argv++;
 104           argp += z;
 105     }
 106
 107   return;
 108 }
 109
 110 /* Perform machine dependent cif processing */
 111 ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
 112 {
 113   /* Round the stack up to a multiple of 8 bytes.  This isn't needed
 114      everywhere, but it is on some platforms, and it doesn't harm anything
 115      when it isn't needed.  */
 116   cif->bytes = (cif->bytes + 7) & ~7;
 117
 118   /* Set the return type flag */
 119   switch (cif->rtype->type)
 120     {
 121     case FFI_TYPE_VOID:
 122     case FFI_TYPE_FLOAT:
 123     case FFI_TYPE_DOUBLE:
 124       cif->flags = (unsigned) cif->rtype->type;
 125       break;
 126
 127     case FFI_TYPE_SINT64:
 128     case FFI_TYPE_UINT64:
 129       cif->flags = (unsigned) FFI_TYPE_SINT64;
 130       break;
 131
 132     case FFI_TYPE_STRUCT:
 133       if (cif->rtype->size <= 4)
 134         /* A Composite Type not larger than 4 bytes is returned in r0.  */
 135         cif->flags = (unsigned)FFI_TYPE_INT;
 136       else
 137         /* A Composite Type larger than 4 bytes, or whose size cannot
 138            be determined statically ... is stored in memory at an
 139            address passed [in r0].  */
 140         cif->flags = (unsigned)FFI_TYPE_STRUCT;
 141       break;
 142
 143     default:
 144       cif->flags = FFI_TYPE_INT;
 145       break;
 146     }
 147
 148   return FFI_OK;
 149 }
 150
 151 extern void ffi_call_SYSV(void (*)(char *, extended_cif *), extended_cif *,
 152                           unsigned, unsigned, unsigned *, void (*fn)());
 153
 154 void ffi_call(ffi_cif *cif, void (*fn)(), void *rvalue, void **avalue)
 155 {
 156   extended_cif ecif;
 157
 158   int small_struct = (cif->flags == FFI_TYPE_INT
 159                       && cif->rtype->type == FFI_TYPE_STRUCT);
 160
 161   ecif.cif = cif;
 162   ecif.avalue = avalue;
 163
 164   unsigned int temp;
 165
 166   /* If the return value is a struct and we don't have a return */
 167   /* value address then we need to make one                     */
 168
 169   if ((rvalue == NULL) &&
 170       (cif->flags == FFI_TYPE_STRUCT))
 171     {
 172       ecif.rvalue = alloca(cif->rtype->size);
 173     }
 174   else if (small_struct)
 175     ecif.rvalue = &temp;
 176   else
 177     ecif.rvalue = rvalue;
 178
 179   switch (cif->abi)
 180     {
 181     case FFI_SYSV:
 182       ffi_call_SYSV(ffi_prep_args, &ecif, cif->bytes, cif->flags, ecif.rvalue,
 183                     fn);
 184
 185       break;
 186     default:
 187       FFI_ASSERT(0);
 188       break;
 189     }
 190   if (small_struct)
 191     memcpy (rvalue, &temp, cif->rtype->size);
 192 }
 193
 194 /** private members **/
 195
 196 static void ffi_prep_incoming_args_SYSV (char *stack, void **ret,
 197                                          void** args, ffi_cif* cif);
 198
 199 void ffi_closure_SYSV (ffi_closure *);
 200
 201 /* This function is jumped to by the trampoline */
 202
 203 unsigned int
 204 ffi_closure_SYSV_inner (closure, respp, args)
 205      ffi_closure *closure;
 206      void **respp;
 207      void *args;
 208 {
 209   // our various things...
 210   ffi_cif       *cif;
 211   void         **arg_area;
 212
 213   cif         = closure->cif;
 214   arg_area    = (void**) alloca (cif->nargs * sizeof (void*));
 215
 216   /* this call will initialize ARG_AREA, such that each
 217    * element in that array points to the corresponding
 218    * value on the stack; and if the function returns
 219    * a structure, it will re-set RESP to point to the
 220    * structure return address.  */
 221
 222   ffi_prep_incoming_args_SYSV(args, respp, arg_area, cif);
 223
 224   (closure->fun) (cif, *respp, arg_area, closure->user_data);
 225
 226   return cif->flags;
 227 }
 228
 229 /*@-exportheader@*/
 230 static void
 231 ffi_prep_incoming_args_SYSV(char *stack, void **rvalue,
 232                             void **avalue, ffi_cif *cif)
 233 /*@=exportheader@*/
 234 {
 235   register unsigned int i;
 236   register void **p_argv;
 237   register char *argp;
 238   register ffi_type **p_arg;
 239
 240   argp = stack;
 241
 242   if ( cif->flags == FFI_TYPE_STRUCT ) {
 243     *rvalue = *(void **) argp;
 244     argp += 4;
 245   }
 246
 247   p_argv = avalue;
 248
 249   for (i = cif->nargs, p_arg = cif->arg_types; (i != 0); i--, p_arg++)
 250     {
 251       size_t z;
 252
 253       size_t alignment = (*p_arg)->alignment;
 254       if (alignment < 4)
 255         alignment = 4;
 256       /* Align if necessary */
 257       if ((alignment - 1) & (unsigned) argp) {
 258         argp = (char *) ALIGN(argp, alignment);
 259       }
 260
 261       z = (*p_arg)->size;
 262
 263       /* because we're little endian, this is what it turns into.   */
 264
 265       *p_argv = (void*) argp;
 266
 267       p_argv++;
 268       argp += z;
 269     }
 270
 271   return;
 272 }
 273
 274 /* How to make a trampoline.  */
 275
 276 #define FFI_INIT_TRAMPOLINE(TRAMP,FUN,CTX)                              \
 277 ({ unsigned char *__tramp = (unsigned char*)(TRAMP);                    \
 278    unsigned int  __fun = (unsigned int)(FUN);                           \
 279    unsigned int  __ctx = (unsigned int)(CTX);                           \
 280    *(unsigned int*) &__tramp[0] = 0xe92d000f; /* stmfd sp!, {r0-r3} */  \
 281    *(unsigned int*) &__tramp[4] = 0xe59f0000; /* ldr r0, [pc] */        \
 282    *(unsigned int*) &__tramp[8] = 0xe59ff000; /* ldr pc, [pc] */        \
 283    *(unsigned int*) &__tramp[12] = __ctx;                               \
 284    *(unsigned int*) &__tramp[16] = __fun;                               \
 285    __clear_cache((&__tramp[0]), (&__tramp[19]));                        \
 286  })
 287
 288
 289 /* the cif must already be prep'ed */
 290
 291 ffi_status
 292 ffi_prep_closure_loc (ffi_closure* closure,
 293                       ffi_cif* cif,
 294                       void (*fun)(ffi_cif*,void*,void**,void*),
 295                       void *user_data,
 296                       void *codeloc)
 297 {
 298   FFI_ASSERT (cif->abi == FFI_SYSV);
 299
 300   FFI_INIT_TRAMPOLINE (&closure->tramp[0], \
 301                        &ffi_closure_SYSV,  \
 302                        codeloc);
 303
 304   closure->cif  = cif;
 305   closure->user_data = user_data;
 306   closure->fun  = fun;
 307
 308   return FFI_OK;
 309 }