/Modules/_ctypes/libffi/src/arm/ffi.c

  1/* -----------------------------------------------------------------------
  2   ffi.c - Copyright (c) 1998, 2008  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
 35void 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 */
111ffi_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
151extern void ffi_call_SYSV(void (*)(char *, extended_cif *), extended_cif *,
152			  unsigned, unsigned, unsigned *, void (*fn)(void));
153
154void ffi_call(ffi_cif *cif, void (*fn)(void), 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
196static void ffi_prep_incoming_args_SYSV (char *stack, void **ret,
197					 void** args, ffi_cif* cif);
198
199void ffi_closure_SYSV (ffi_closure *);
200
201/* This function is jumped to by the trampoline */
202
203unsigned int
204ffi_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@*/
230static void 
231ffi_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
291ffi_status
292ffi_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}