1 /* -----------------------------------------------------------------------
2 ffi.c - Copyright (c) 2011 Anthony Green
3 Copyright (c) 2009 Bradley Smith <brad@brad-smith.co.uk>
4
5 AVR32 Foreign Function Interface
6
7 Permission is hereby granted, free of charge, to any person obtaining
8 a copy of this software and associated documentation files (the
9 ``Software''), to deal in the Software without restriction, including
10 without limitation the rights to use, copy, modify, merge, publish,
11 distribute, sublicense, and/or sell copies of the Software, and to
12 permit persons to whom the Software is furnished to do so, subject to
13 the following conditions:
14
15 The above copyright notice and this permission notice shall be included
16 in all copies or substantial portions of the Software.
17
18 THE SOFTWARE IS PROVIDED ``AS IS'', WITHOUT WARRANTY OF ANY KIND,
19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
22 HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
23 WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
25 DEALINGS IN THE SOFTWARE.
26 ----------------------------------------------------------------------- */
27
28 #include <ffi.h>
29 #include <ffi_common.h>
30
31 #include <stdlib.h>
32 #include <stdio.h>
33 #include <unistd.h>
34 #include <asm/unistd.h>
35
36 /* #define DEBUG */
37
38 extern void ffi_call_SYSV(void (*)(char *, extended_cif *), extended_cif *,
39 unsigned int, unsigned int, unsigned int*, unsigned int,
40 void (*fn)(void));
41 extern void ffi_closure_SYSV (ffi_closure *);
42
pass_struct_on_stack(ffi_type * type)43 unsigned int pass_struct_on_stack(ffi_type *type)
44 {
45 if(type->type != FFI_TYPE_STRUCT)
46 return 0;
47
48 if(type->alignment < type->size &&
49 !(type->size == 4 || type->size == 8) &&
50 !(type->size == 8 && type->alignment >= 4))
51 return 1;
52
53 if(type->size == 3 || type->size == 5 || type->size == 6 ||
54 type->size == 7)
55 return 1;
56
57 return 0;
58 }
59
60 /* ffi_prep_args is called by the assembly routine once stack space
61 * has been allocated for the function's arguments
62 *
63 * This is annoyingly complex since we need to keep track of used
64 * registers.
65 */
66
ffi_prep_args(char * stack,extended_cif * ecif)67 void ffi_prep_args(char *stack, extended_cif *ecif)
68 {
69 unsigned int i;
70 void **p_argv;
71 ffi_type **p_arg;
72 char *reg_base = stack;
73 char *stack_base = stack + 20;
74 unsigned int stack_offset = 0;
75 unsigned int reg_mask = 0;
76
77 p_argv = ecif->avalue;
78
79 /* If cif->flags is struct then we know it's not passed in registers */
80 if(ecif->cif->flags == FFI_TYPE_STRUCT)
81 {
82 *(void**)reg_base = ecif->rvalue;
83 reg_mask |= 1;
84 }
85
86 for(i = 0, p_arg = ecif->cif->arg_types; i < ecif->cif->nargs;
87 i++, p_arg++)
88 {
89 size_t z = (*p_arg)->size;
90 int alignment = (*p_arg)->alignment;
91 int type = (*p_arg)->type;
92 char *addr = 0;
93
94 if(z % 4 != 0)
95 z += (4 - z % 4);
96
97 if(reg_mask != 0x1f)
98 {
99 if(pass_struct_on_stack(*p_arg))
100 {
101 addr = stack_base + stack_offset;
102 stack_offset += z;
103 }
104 else if(z == sizeof(int))
105 {
106 char index = 0;
107
108 while((reg_mask >> index) & 1)
109 index++;
110
111 addr = reg_base + (index * 4);
112 reg_mask |= (1 << index);
113 }
114 else if(z == 2 * sizeof(int))
115 {
116 if(!((reg_mask >> 1) & 1))
117 {
118 addr = reg_base + 4;
119 reg_mask |= (3 << 1);
120 }
121 else if(!((reg_mask >> 3) & 1))
122 {
123 addr = reg_base + 12;
124 reg_mask |= (3 << 3);
125 }
126 }
127 }
128
129 if(!addr)
130 {
131 addr = stack_base + stack_offset;
132 stack_offset += z;
133 }
134
135 if(type == FFI_TYPE_STRUCT && (*p_arg)->elements[1] == NULL)
136 type = (*p_arg)->elements[0]->type;
137
138 switch(type)
139 {
140 case FFI_TYPE_UINT8:
141 *(unsigned int *)addr = (unsigned int)*(UINT8 *)(*p_argv);
142 break;
143 case FFI_TYPE_SINT8:
144 *(signed int *)addr = (signed int)*(SINT8 *)(*p_argv);
145 break;
146 case FFI_TYPE_UINT16:
147 *(unsigned int *)addr = (unsigned int)*(UINT16 *)(*p_argv);
148 break;
149 case FFI_TYPE_SINT16:
150 *(signed int *)addr = (signed int)*(SINT16 *)(*p_argv);
151 break;
152 default:
153 memcpy(addr, *p_argv, z);
154 }
155
156 p_argv++;
157 }
158
159 #ifdef DEBUG
160 /* Debugging */
161 for(i = 0; i < 5; i++)
162 {
163 if((reg_mask & (1 << i)) == 0)
164 printf("r%d: (unused)\n", 12 - i);
165 else
166 printf("r%d: 0x%08x\n", 12 - i, ((unsigned int*)reg_base)[i]);
167 }
168
169 for(i = 0; i < stack_offset / 4; i++)
170 {
171 printf("sp+%d: 0x%08x\n", i*4, ((unsigned int*)stack_base)[i]);
172 }
173 #endif
174 }
175
176 /* Perform machine dependent cif processing */
ffi_prep_cif_machdep(ffi_cif * cif)177 ffi_status ffi_prep_cif_machdep(ffi_cif *cif)
178 {
179 /* Round the stack up to a multiple of 8 bytes. This isn't needed
180 * everywhere, but it is on some platforms, and it doesn't harm
181 * anything when it isn't needed. */
182 cif->bytes = (cif->bytes + 7) & ~7;
183
184 /* Flag to indicate that he return value is in fact a struct */
185 cif->rstruct_flag = 0;
186
187 /* Set the return type flag */
188 switch(cif->rtype->type)
189 {
190 case FFI_TYPE_SINT8:
191 case FFI_TYPE_UINT8:
192 cif->flags = (unsigned)FFI_TYPE_UINT8;
193 break;
194 case FFI_TYPE_SINT16:
195 case FFI_TYPE_UINT16:
196 cif->flags = (unsigned)FFI_TYPE_UINT16;
197 break;
198 case FFI_TYPE_FLOAT:
199 case FFI_TYPE_SINT32:
200 case FFI_TYPE_UINT32:
201 case FFI_TYPE_POINTER:
202 cif->flags = (unsigned)FFI_TYPE_UINT32;
203 break;
204 case FFI_TYPE_DOUBLE:
205 case FFI_TYPE_SINT64:
206 case FFI_TYPE_UINT64:
207 cif->flags = (unsigned)FFI_TYPE_UINT64;
208 break;
209 case FFI_TYPE_STRUCT:
210 cif->rstruct_flag = 1;
211 if(!pass_struct_on_stack(cif->rtype))
212 {
213 if(cif->rtype->size <= 1)
214 cif->flags = (unsigned)FFI_TYPE_UINT8;
215 else if(cif->rtype->size <= 2)
216 cif->flags = (unsigned)FFI_TYPE_UINT16;
217 else if(cif->rtype->size <= 4)
218 cif->flags = (unsigned)FFI_TYPE_UINT32;
219 else if(cif->rtype->size <= 8)
220 cif->flags = (unsigned)FFI_TYPE_UINT64;
221 else
222 cif->flags = (unsigned)cif->rtype->type;
223 }
224 else
225 cif->flags = (unsigned)cif->rtype->type;
226 break;
227 default:
228 cif->flags = (unsigned)cif->rtype->type;
229 break;
230 }
231
232 return FFI_OK;
233 }
234
ffi_call(ffi_cif * cif,void (* fn)(void),void * rvalue,void ** avalue)235 void ffi_call(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
236 {
237 extended_cif ecif;
238
239 unsigned int size = 0, i = 0;
240 ffi_type **p_arg;
241
242 ecif.cif = cif;
243 ecif.avalue = avalue;
244
245 for(i = 0, p_arg = cif->arg_types; i < cif->nargs; i++, p_arg++)
246 size += (*p_arg)->size + (4 - (*p_arg)->size % 4);
247
248 /* If the return value is a struct and we don't have a return value
249 * address then we need to make one */
250
251 /* If cif->flags is struct then it's not suitable for registers */
252 if((rvalue == NULL) && (cif->flags == FFI_TYPE_STRUCT))
253 ecif.rvalue = alloca(cif->rtype->size);
254 else
255 ecif.rvalue = rvalue;
256
257 switch(cif->abi)
258 {
259 case FFI_SYSV:
260 ffi_call_SYSV(ffi_prep_args, &ecif, size, cif->flags,
261 ecif.rvalue, cif->rstruct_flag, fn);
262 break;
263 default:
264 FFI_ASSERT(0);
265 break;
266 }
267 }
268
ffi_prep_incoming_args_SYSV(char * stack,void ** rvalue,void ** avalue,ffi_cif * cif)269 static void ffi_prep_incoming_args_SYSV(char *stack, void **rvalue,
270 void **avalue, ffi_cif *cif)
271 {
272 register unsigned int i, reg_mask = 0;
273 register void **p_argv;
274 register ffi_type **p_arg;
275 register char *reg_base = stack;
276 register char *stack_base = stack + 20;
277 register unsigned int stack_offset = 0;
278
279 #ifdef DEBUG
280 /* Debugging */
281 for(i = 0; i < cif->nargs + 7; i++)
282 {
283 printf("sp+%d: 0x%08x\n", i*4, ((unsigned int*)stack)[i]);
284 }
285 #endif
286
287 /* If cif->flags is struct then we know it's not passed in registers */
288 if(cif->flags == FFI_TYPE_STRUCT)
289 {
290 *rvalue = *(void **)reg_base;
291 reg_mask |= 1;
292 }
293
294 p_argv = avalue;
295
296 for(i = 0, p_arg = cif->arg_types; i < cif->nargs; i++, p_arg++)
297 {
298 size_t z = (*p_arg)->size;
299 int alignment = (*p_arg)->alignment;
300
301 *p_argv = 0;
302
303 if(z % 4 != 0)
304 z += (4 - z % 4);
305
306 if(reg_mask != 0x1f)
307 {
308 if(pass_struct_on_stack(*p_arg))
309 {
310 *p_argv = (void*)stack_base + stack_offset;
311 stack_offset += z;
312 }
313 else if(z <= sizeof(int))
314 {
315 char index = 0;
316
317 while((reg_mask >> index) & 1)
318 index++;
319
320 *p_argv = (void*)reg_base + (index * 4);
321 reg_mask |= (1 << index);
322 }
323 else if(z == 2 * sizeof(int))
324 {
325 if(!((reg_mask >> 1) & 1))
326 {
327 *p_argv = (void*)reg_base + 4;
328 reg_mask |= (3 << 1);
329 }
330 else if(!((reg_mask >> 3) & 1))
331 {
332 *p_argv = (void*)reg_base + 12;
333 reg_mask |= (3 << 3);
334 }
335 }
336 }
337
338 if(!*p_argv)
339 {
340 *p_argv = (void*)stack_base + stack_offset;
341 stack_offset += z;
342 }
343
344 if((*p_arg)->type != FFI_TYPE_STRUCT ||
345 (*p_arg)->elements[1] == NULL)
346 {
347 if(alignment == 1)
348 **(unsigned int**)p_argv <<= 24;
349 else if(alignment == 2)
350 **(unsigned int**)p_argv <<= 16;
351 }
352
353 p_argv++;
354 }
355
356 #ifdef DEBUG
357 /* Debugging */
358 for(i = 0; i < cif->nargs; i++)
359 {
360 printf("sp+%d: 0x%08x\n", i*4, *(((unsigned int**)avalue)[i]));
361 }
362 #endif
363 }
364
365 /* This function is jumped to by the trampoline */
366
ffi_closure_SYSV_inner(ffi_closure * closure,void ** respp,void * args)367 unsigned int ffi_closure_SYSV_inner(ffi_closure *closure, void **respp,
368 void *args)
369 {
370 ffi_cif *cif;
371 void **arg_area;
372 unsigned int i, size = 0;
373 ffi_type **p_arg;
374
375 cif = closure->cif;
376
377 for(i = 0, p_arg = cif->arg_types; i < cif->nargs; i++, p_arg++)
378 size += (*p_arg)->size + (4 - (*p_arg)->size % 4);
379
380 arg_area = (void **)alloca(size);
381
382 /* this call will initialize ARG_AREA, such that each element in that
383 * array points to the corresponding value on the stack; and if the
384 * function returns a structure, it will re-set RESP to point to the
385 * structure return address. */
386
387 ffi_prep_incoming_args_SYSV(args, respp, arg_area, cif);
388
389 (closure->fun)(cif, *respp, arg_area, closure->user_data);
390
391 return cif->flags;
392 }
393
ffi_prep_closure_loc(ffi_closure * closure,ffi_cif * cif,void (* fun)(ffi_cif *,void *,void **,void *),void * user_data,void * codeloc)394 ffi_status ffi_prep_closure_loc(ffi_closure* closure, ffi_cif* cif,
395 void (*fun)(ffi_cif*, void*, void**, void*), void *user_data,
396 void *codeloc)
397 {
398 if (cif->abi != FFI_SYSV)
399 return FFI_BAD_ABI;
400
401 unsigned char *__tramp = (unsigned char*)(&closure->tramp[0]);
402 unsigned int __fun = (unsigned int)(&ffi_closure_SYSV);
403 unsigned int __ctx = (unsigned int)(codeloc);
404 unsigned int __rstruct_flag = (unsigned int)(cif->rstruct_flag);
405 unsigned int __inner = (unsigned int)(&ffi_closure_SYSV_inner);
406 *(unsigned int*) &__tramp[0] = 0xebcd1f00; /* pushm r8-r12 */
407 *(unsigned int*) &__tramp[4] = 0xfefc0010; /* ld.w r12, pc[16] */
408 *(unsigned int*) &__tramp[8] = 0xfefb0010; /* ld.w r11, pc[16] */
409 *(unsigned int*) &__tramp[12] = 0xfefa0010; /* ld.w r10, pc[16] */
410 *(unsigned int*) &__tramp[16] = 0xfeff0010; /* ld.w pc, pc[16] */
411 *(unsigned int*) &__tramp[20] = __ctx;
412 *(unsigned int*) &__tramp[24] = __rstruct_flag;
413 *(unsigned int*) &__tramp[28] = __inner;
414 *(unsigned int*) &__tramp[32] = __fun;
415 syscall(__NR_cacheflush, 0, (&__tramp[0]), 36);
416
417 closure->cif = cif;
418 closure->user_data = user_data;
419 closure->fun = fun;
420
421 return FFI_OK;
422 }
423
424