1 /*
2 ** FFI C callback handling.
3 ** Copyright (C) 2005-2017 Mike Pall. See Copyright Notice in luajit.h
4 */
5
6 #include "lj_obj.h"
7
8 #if LJ_HASFFI
9
10 #include "lj_gc.h"
11 #include "lj_err.h"
12 #include "lj_tab.h"
13 #include "lj_state.h"
14 #include "lj_frame.h"
15 #include "lj_ctype.h"
16 #include "lj_cconv.h"
17 #include "lj_ccall.h"
18 #include "lj_ccallback.h"
19 #include "lj_target.h"
20 #include "lj_mcode.h"
21 #include "lj_trace.h"
22 #include "lj_vm.h"
23
24 /* -- Target-specific handling of callback slots -------------------------- */
25
26 #define CALLBACK_MCODE_SIZE (LJ_PAGESIZE * LJ_NUM_CBPAGE)
27
28 #if LJ_OS_NOJIT
29
30 /* Callbacks disabled. */
31 #define CALLBACK_SLOT2OFS(slot) (0*(slot))
32 #define CALLBACK_OFS2SLOT(ofs) (0*(ofs))
33 #define CALLBACK_MAX_SLOT 0
34
35 #elif LJ_TARGET_X86ORX64
36
37 #define CALLBACK_MCODE_HEAD (LJ_64 ? 8 : 0)
38 #define CALLBACK_MCODE_GROUP (-2+1+2+(LJ_GC64 ? 10 : 5)+(LJ_64 ? 6 : 5))
39
40 #define CALLBACK_SLOT2OFS(slot) \
41 (CALLBACK_MCODE_HEAD + CALLBACK_MCODE_GROUP*((slot)/32) + 4*(slot))
42
CALLBACK_OFS2SLOT(MSize ofs)43 static MSize CALLBACK_OFS2SLOT(MSize ofs)
44 {
45 MSize group;
46 ofs -= CALLBACK_MCODE_HEAD;
47 group = ofs / (32*4 + CALLBACK_MCODE_GROUP);
48 return (ofs % (32*4 + CALLBACK_MCODE_GROUP))/4 + group*32;
49 }
50
51 #define CALLBACK_MAX_SLOT \
52 (((CALLBACK_MCODE_SIZE-CALLBACK_MCODE_HEAD)/(CALLBACK_MCODE_GROUP+4*32))*32)
53
54 #elif LJ_TARGET_ARM
55
56 #define CALLBACK_MCODE_HEAD 32
57
58 #elif LJ_TARGET_ARM64
59
60 #define CALLBACK_MCODE_HEAD 32
61
62 #elif LJ_TARGET_PPC
63
64 #define CALLBACK_MCODE_HEAD 24
65
66 #elif LJ_TARGET_MIPS32
67
68 #define CALLBACK_MCODE_HEAD 20
69
70 #elif LJ_TARGET_MIPS64
71
72 #define CALLBACK_MCODE_HEAD 52
73
74 #else
75
76 /* Missing support for this architecture. */
77 #define CALLBACK_SLOT2OFS(slot) (0*(slot))
78 #define CALLBACK_OFS2SLOT(ofs) (0*(ofs))
79 #define CALLBACK_MAX_SLOT 0
80
81 #endif
82
83 #ifndef CALLBACK_SLOT2OFS
84 #define CALLBACK_SLOT2OFS(slot) (CALLBACK_MCODE_HEAD + 8*(slot))
85 #define CALLBACK_OFS2SLOT(ofs) (((ofs)-CALLBACK_MCODE_HEAD)/8)
86 #define CALLBACK_MAX_SLOT (CALLBACK_OFS2SLOT(CALLBACK_MCODE_SIZE))
87 #endif
88
89 /* Convert callback slot number to callback function pointer. */
callback_slot2ptr(CTState * cts,MSize slot)90 static void *callback_slot2ptr(CTState *cts, MSize slot)
91 {
92 return (uint8_t *)cts->cb.mcode + CALLBACK_SLOT2OFS(slot);
93 }
94
95 /* Convert callback function pointer to slot number. */
lj_ccallback_ptr2slot(CTState * cts,void * p)96 MSize lj_ccallback_ptr2slot(CTState *cts, void *p)
97 {
98 uintptr_t ofs = (uintptr_t)((uint8_t *)p -(uint8_t *)cts->cb.mcode);
99 if (ofs < CALLBACK_MCODE_SIZE) {
100 MSize slot = CALLBACK_OFS2SLOT((MSize)ofs);
101 if (CALLBACK_SLOT2OFS(slot) == (MSize)ofs)
102 return slot;
103 }
104 return ~0u; /* Not a known callback function pointer. */
105 }
106
107 /* Initialize machine code for callback function pointers. */
108 #if LJ_OS_NOJIT
109 /* Disabled callback support. */
110 #define callback_mcode_init(g, p) UNUSED(p)
111 #elif LJ_TARGET_X86ORX64
callback_mcode_init(global_State * g,uint8_t * page)112 static void callback_mcode_init(global_State *g, uint8_t *page)
113 {
114 uint8_t *p = page;
115 uint8_t *target = (uint8_t *)(void *)lj_vm_ffi_callback;
116 MSize slot;
117 #if LJ_64
118 *(void **)p = target; p += 8;
119 #endif
120 for (slot = 0; slot < CALLBACK_MAX_SLOT; slot++) {
121 /* mov al, slot; jmp group */
122 *p++ = XI_MOVrib | RID_EAX; *p++ = (uint8_t)slot;
123 if ((slot & 31) == 31 || slot == CALLBACK_MAX_SLOT-1) {
124 /* push ebp/rbp; mov ah, slot>>8; mov ebp, &g. */
125 *p++ = XI_PUSH + RID_EBP;
126 *p++ = XI_MOVrib | (RID_EAX+4); *p++ = (uint8_t)(slot >> 8);
127 #if LJ_GC64
128 *p++ = 0x48; *p++ = XI_MOVri | RID_EBP;
129 *(uint64_t *)p = (uint64_t)(g); p += 8;
130 #else
131 *p++ = XI_MOVri | RID_EBP;
132 *(int32_t *)p = i32ptr(g); p += 4;
133 #endif
134 #if LJ_64
135 /* jmp [rip-pageofs] where lj_vm_ffi_callback is stored. */
136 *p++ = XI_GROUP5; *p++ = XM_OFS0 + (XOg_JMP<<3) + RID_EBP;
137 *(int32_t *)p = (int32_t)(page-(p+4)); p += 4;
138 #else
139 /* jmp lj_vm_ffi_callback. */
140 *p++ = XI_JMP; *(int32_t *)p = target-(p+4); p += 4;
141 #endif
142 } else {
143 *p++ = XI_JMPs; *p++ = (uint8_t)((2+2)*(31-(slot&31)) - 2);
144 }
145 }
146 lua_assert(p - page <= CALLBACK_MCODE_SIZE);
147 }
148 #elif LJ_TARGET_ARM
callback_mcode_init(global_State * g,uint32_t * page)149 static void callback_mcode_init(global_State *g, uint32_t *page)
150 {
151 uint32_t *p = page;
152 void *target = (void *)lj_vm_ffi_callback;
153 MSize slot;
154 /* This must match with the saveregs macro in buildvm_arm.dasc. */
155 *p++ = ARMI_SUB|ARMF_D(RID_R12)|ARMF_N(RID_R12)|ARMF_M(RID_PC);
156 *p++ = ARMI_PUSH|ARMF_N(RID_SP)|RSET_RANGE(RID_R4,RID_R11+1)|RID2RSET(RID_LR);
157 *p++ = ARMI_SUB|ARMI_K12|ARMF_D(RID_R12)|ARMF_N(RID_R12)|CALLBACK_MCODE_HEAD;
158 *p++ = ARMI_STR|ARMI_LS_P|ARMI_LS_W|ARMF_D(RID_R12)|ARMF_N(RID_SP)|(CFRAME_SIZE-4*9);
159 *p++ = ARMI_LDR|ARMI_LS_P|ARMI_LS_U|ARMF_D(RID_R12)|ARMF_N(RID_PC);
160 *p++ = ARMI_LDR|ARMI_LS_P|ARMI_LS_U|ARMF_D(RID_PC)|ARMF_N(RID_PC);
161 *p++ = u32ptr(g);
162 *p++ = u32ptr(target);
163 for (slot = 0; slot < CALLBACK_MAX_SLOT; slot++) {
164 *p++ = ARMI_MOV|ARMF_D(RID_R12)|ARMF_M(RID_PC);
165 *p = ARMI_B | ((page-p-2) & 0x00ffffffu);
166 p++;
167 }
168 lua_assert(p - page <= CALLBACK_MCODE_SIZE);
169 }
170 #elif LJ_TARGET_ARM64
callback_mcode_init(global_State * g,uint32_t * page)171 static void callback_mcode_init(global_State *g, uint32_t *page)
172 {
173 uint32_t *p = page;
174 void *target = (void *)lj_vm_ffi_callback;
175 MSize slot;
176 *p++ = A64I_LDRLx | A64F_D(RID_X11) | A64F_S19(4);
177 *p++ = A64I_LDRLx | A64F_D(RID_X10) | A64F_S19(5);
178 *p++ = A64I_BR | A64F_N(RID_X11);
179 *p++ = A64I_NOP;
180 ((void **)p)[0] = target;
181 ((void **)p)[1] = g;
182 p += 4;
183 for (slot = 0; slot < CALLBACK_MAX_SLOT; slot++) {
184 *p++ = A64I_MOVZw | A64F_D(RID_X9) | A64F_U16(slot);
185 *p = A64I_B | A64F_S26((page-p) & 0x03ffffffu);
186 p++;
187 }
188 lua_assert(p - page <= CALLBACK_MCODE_SIZE);
189 }
190 #elif LJ_TARGET_PPC
callback_mcode_init(global_State * g,uint32_t * page)191 static void callback_mcode_init(global_State *g, uint32_t *page)
192 {
193 uint32_t *p = page;
194 void *target = (void *)lj_vm_ffi_callback;
195 MSize slot;
196 *p++ = PPCI_LIS | PPCF_T(RID_TMP) | (u32ptr(target) >> 16);
197 *p++ = PPCI_LIS | PPCF_T(RID_R12) | (u32ptr(g) >> 16);
198 *p++ = PPCI_ORI | PPCF_A(RID_TMP)|PPCF_T(RID_TMP) | (u32ptr(target) & 0xffff);
199 *p++ = PPCI_ORI | PPCF_A(RID_R12)|PPCF_T(RID_R12) | (u32ptr(g) & 0xffff);
200 *p++ = PPCI_MTCTR | PPCF_T(RID_TMP);
201 *p++ = PPCI_BCTR;
202 for (slot = 0; slot < CALLBACK_MAX_SLOT; slot++) {
203 *p++ = PPCI_LI | PPCF_T(RID_R11) | slot;
204 *p = PPCI_B | (((page-p) & 0x00ffffffu) << 2);
205 p++;
206 }
207 lua_assert(p - page <= CALLBACK_MCODE_SIZE);
208 }
209 #elif LJ_TARGET_MIPS
callback_mcode_init(global_State * g,uint32_t * page)210 static void callback_mcode_init(global_State *g, uint32_t *page)
211 {
212 uint32_t *p = page;
213 uintptr_t target = (uintptr_t)(void *)lj_vm_ffi_callback;
214 uintptr_t ug = (uintptr_t)(void *)g;
215 MSize slot;
216 #if LJ_TARGET_MIPS32
217 *p++ = MIPSI_LUI | MIPSF_T(RID_R3) | (target >> 16);
218 *p++ = MIPSI_LUI | MIPSF_T(RID_R2) | (ug >> 16);
219 #else
220 *p++ = MIPSI_LUI | MIPSF_T(RID_R3) | (target >> 48);
221 *p++ = MIPSI_LUI | MIPSF_T(RID_R2) | (ug >> 48);
222 *p++ = MIPSI_ORI | MIPSF_T(RID_R3)|MIPSF_S(RID_R3) | ((target >> 32) & 0xffff);
223 *p++ = MIPSI_ORI | MIPSF_T(RID_R2)|MIPSF_S(RID_R2) | ((ug >> 32) & 0xffff);
224 *p++ = MIPSI_DSLL | MIPSF_D(RID_R3)|MIPSF_T(RID_R3) | MIPSF_A(16);
225 *p++ = MIPSI_DSLL | MIPSF_D(RID_R2)|MIPSF_T(RID_R2) | MIPSF_A(16);
226 *p++ = MIPSI_ORI | MIPSF_T(RID_R3)|MIPSF_S(RID_R3) | ((target >> 16) & 0xffff);
227 *p++ = MIPSI_ORI | MIPSF_T(RID_R2)|MIPSF_S(RID_R2) | ((ug >> 16) & 0xffff);
228 *p++ = MIPSI_DSLL | MIPSF_D(RID_R3)|MIPSF_T(RID_R3) | MIPSF_A(16);
229 *p++ = MIPSI_DSLL | MIPSF_D(RID_R2)|MIPSF_T(RID_R2) | MIPSF_A(16);
230 #endif
231 *p++ = MIPSI_ORI | MIPSF_T(RID_R3)|MIPSF_S(RID_R3) | (target & 0xffff);
232 *p++ = MIPSI_JR | MIPSF_S(RID_R3);
233 *p++ = MIPSI_ORI | MIPSF_T(RID_R2)|MIPSF_S(RID_R2) | (ug & 0xffff);
234 for (slot = 0; slot < CALLBACK_MAX_SLOT; slot++) {
235 *p = MIPSI_B | ((page-p-1) & 0x0000ffffu);
236 p++;
237 *p++ = MIPSI_LI | MIPSF_T(RID_R1) | slot;
238 }
239 lua_assert(p - page <= CALLBACK_MCODE_SIZE);
240 }
241 #else
242 /* Missing support for this architecture. */
243 #define callback_mcode_init(g, p) UNUSED(p)
244 #endif
245
246 /* -- Machine code management --------------------------------------------- */
247
248 #if LJ_TARGET_WINDOWS
249
250 #define WIN32_LEAN_AND_MEAN
251 #include <windows.h>
252
253 #elif LJ_TARGET_POSIX
254
255 #include <sys/mman.h>
256 #ifndef MAP_ANONYMOUS
257 #define MAP_ANONYMOUS MAP_ANON
258 #endif
259
260 #endif
261
262 /* Allocate and initialize area for callback function pointers. */
callback_mcode_new(CTState * cts)263 static void callback_mcode_new(CTState *cts)
264 {
265 size_t sz = (size_t)CALLBACK_MCODE_SIZE;
266 void *p;
267 if (CALLBACK_MAX_SLOT == 0)
268 lj_err_caller(cts->L, LJ_ERR_FFI_CBACKOV);
269 #if LJ_TARGET_WINDOWS
270 p = VirtualAlloc(NULL, sz, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE);
271 if (!p)
272 lj_err_caller(cts->L, LJ_ERR_FFI_CBACKOV);
273 #elif LJ_TARGET_POSIX
274 p = mmap(NULL, sz, (PROT_READ|PROT_WRITE), MAP_PRIVATE|MAP_ANONYMOUS,
275 -1, 0);
276 if (p == MAP_FAILED)
277 lj_err_caller(cts->L, LJ_ERR_FFI_CBACKOV);
278 #else
279 /* Fallback allocator. Fails if memory is not executable by default. */
280 p = lj_mem_new(cts->L, sz);
281 #endif
282 cts->cb.mcode = p;
283 callback_mcode_init(cts->g, p);
284 lj_mcode_sync(p, (char *)p + sz);
285 #if LJ_TARGET_WINDOWS
286 {
287 DWORD oprot;
288 VirtualProtect(p, sz, PAGE_EXECUTE_READ, &oprot);
289 }
290 #elif LJ_TARGET_POSIX
291 mprotect(p, sz, (PROT_READ|PROT_EXEC));
292 #endif
293 }
294
295 /* Free area for callback function pointers. */
lj_ccallback_mcode_free(CTState * cts)296 void lj_ccallback_mcode_free(CTState *cts)
297 {
298 size_t sz = (size_t)CALLBACK_MCODE_SIZE;
299 void *p = cts->cb.mcode;
300 if (p == NULL) return;
301 #if LJ_TARGET_WINDOWS
302 VirtualFree(p, 0, MEM_RELEASE);
303 UNUSED(sz);
304 #elif LJ_TARGET_POSIX
305 munmap(p, sz);
306 #else
307 lj_mem_free(cts->g, p, sz);
308 #endif
309 }
310
311 /* -- C callback entry ---------------------------------------------------- */
312
313 /* Target-specific handling of register arguments. Similar to lj_ccall.c. */
314 #if LJ_TARGET_X86
315
316 #define CALLBACK_HANDLE_REGARG \
317 if (!isfp) { /* Only non-FP values may be passed in registers. */ \
318 if (n > 1) { /* Anything > 32 bit is passed on the stack. */ \
319 if (!LJ_ABI_WIN) ngpr = maxgpr; /* Prevent reordering. */ \
320 } else if (ngpr + 1 <= maxgpr) { \
321 sp = &cts->cb.gpr[ngpr]; \
322 ngpr += n; \
323 goto done; \
324 } \
325 }
326
327 #elif LJ_TARGET_X64 && LJ_ABI_WIN
328
329 /* Windows/x64 argument registers are strictly positional (use ngpr). */
330 #define CALLBACK_HANDLE_REGARG \
331 if (isfp) { \
332 if (ngpr < maxgpr) { sp = &cts->cb.fpr[ngpr++]; UNUSED(nfpr); goto done; } \
333 } else { \
334 if (ngpr < maxgpr) { sp = &cts->cb.gpr[ngpr++]; goto done; } \
335 }
336
337 #elif LJ_TARGET_X64
338
339 #define CALLBACK_HANDLE_REGARG \
340 if (isfp) { \
341 if (nfpr + n <= CCALL_NARG_FPR) { \
342 sp = &cts->cb.fpr[nfpr]; \
343 nfpr += n; \
344 goto done; \
345 } \
346 } else { \
347 if (ngpr + n <= maxgpr) { \
348 sp = &cts->cb.gpr[ngpr]; \
349 ngpr += n; \
350 goto done; \
351 } \
352 }
353
354 #elif LJ_TARGET_ARM
355
356 #if LJ_ABI_SOFTFP
357
358 #define CALLBACK_HANDLE_REGARG_FP1 UNUSED(isfp);
359 #define CALLBACK_HANDLE_REGARG_FP2
360
361 #else
362
363 #define CALLBACK_HANDLE_REGARG_FP1 \
364 if (isfp) { \
365 if (n == 1) { \
366 if (fprodd) { \
367 sp = &cts->cb.fpr[fprodd-1]; \
368 fprodd = 0; \
369 goto done; \
370 } else if (nfpr + 1 <= CCALL_NARG_FPR) { \
371 sp = &cts->cb.fpr[nfpr++]; \
372 fprodd = nfpr; \
373 goto done; \
374 } \
375 } else { \
376 if (nfpr + 1 <= CCALL_NARG_FPR) { \
377 sp = &cts->cb.fpr[nfpr++]; \
378 goto done; \
379 } \
380 } \
381 fprodd = 0; /* No reordering after the first FP value is on stack. */ \
382 } else {
383
384 #define CALLBACK_HANDLE_REGARG_FP2 }
385
386 #endif
387
388 #define CALLBACK_HANDLE_REGARG \
389 CALLBACK_HANDLE_REGARG_FP1 \
390 if (n > 1) ngpr = (ngpr + 1u) & ~1u; /* Align to regpair. */ \
391 if (ngpr + n <= maxgpr) { \
392 sp = &cts->cb.gpr[ngpr]; \
393 ngpr += n; \
394 goto done; \
395 } CALLBACK_HANDLE_REGARG_FP2
396
397 #elif LJ_TARGET_ARM64
398
399 #define CALLBACK_HANDLE_REGARG \
400 if (isfp) { \
401 if (nfpr + n <= CCALL_NARG_FPR) { \
402 sp = &cts->cb.fpr[nfpr]; \
403 nfpr += n; \
404 goto done; \
405 } else { \
406 nfpr = CCALL_NARG_FPR; /* Prevent reordering. */ \
407 } \
408 } else { \
409 if (!LJ_TARGET_IOS && n > 1) \
410 ngpr = (ngpr + 1u) & ~1u; /* Align to regpair. */ \
411 if (ngpr + n <= maxgpr) { \
412 sp = &cts->cb.gpr[ngpr]; \
413 ngpr += n; \
414 goto done; \
415 } else { \
416 ngpr = CCALL_NARG_GPR; /* Prevent reordering. */ \
417 } \
418 }
419
420 #elif LJ_TARGET_PPC
421
422 #define CALLBACK_HANDLE_REGARG \
423 if (isfp) { \
424 if (nfpr + 1 <= CCALL_NARG_FPR) { \
425 sp = &cts->cb.fpr[nfpr++]; \
426 cta = ctype_get(cts, CTID_DOUBLE); /* FPRs always hold doubles. */ \
427 goto done; \
428 } \
429 } else { /* Try to pass argument in GPRs. */ \
430 if (n > 1) { \
431 lua_assert(ctype_isinteger(cta->info) && n == 2); /* int64_t. */ \
432 ngpr = (ngpr + 1u) & ~1u; /* Align int64_t to regpair. */ \
433 } \
434 if (ngpr + n <= maxgpr) { \
435 sp = &cts->cb.gpr[ngpr]; \
436 ngpr += n; \
437 goto done; \
438 } \
439 }
440
441 #define CALLBACK_HANDLE_RET \
442 if (ctype_isfp(ctr->info) && ctr->size == sizeof(float)) \
443 *(double *)dp = *(float *)dp; /* FPRs always hold doubles. */
444
445 #elif LJ_TARGET_MIPS32
446
447 #define CALLBACK_HANDLE_GPR \
448 if (n > 1) ngpr = (ngpr + 1u) & ~1u; /* Align to regpair. */ \
449 if (ngpr + n <= maxgpr) { \
450 sp = &cts->cb.gpr[ngpr]; \
451 ngpr += n; \
452 goto done; \
453 }
454
455 #if !LJ_ABI_SOFTFP /* MIPS32 hard-float */
456 #define CALLBACK_HANDLE_REGARG \
457 if (isfp && nfpr < CCALL_NARG_FPR) { /* Try to pass argument in FPRs. */ \
458 sp = (void *)((uint8_t *)&cts->cb.fpr[nfpr] + ((LJ_BE && n==1) ? 4 : 0)); \
459 nfpr++; ngpr += n; \
460 goto done; \
461 } else { /* Try to pass argument in GPRs. */ \
462 nfpr = CCALL_NARG_FPR; \
463 CALLBACK_HANDLE_GPR \
464 }
465 #else /* MIPS32 soft-float */
466 #define CALLBACK_HANDLE_REGARG \
467 CALLBACK_HANDLE_GPR \
468 UNUSED(isfp);
469 #endif
470
471 #define CALLBACK_HANDLE_RET \
472 if (ctype_isfp(ctr->info) && ctr->size == sizeof(float)) \
473 ((float *)dp)[1] = *(float *)dp;
474
475 #elif LJ_TARGET_MIPS64
476
477 #if !LJ_ABI_SOFTFP /* MIPS64 hard-float */
478 #define CALLBACK_HANDLE_REGARG \
479 if (ngpr + n <= maxgpr) { \
480 sp = isfp ? (void*) &cts->cb.fpr[ngpr] : (void*) &cts->cb.gpr[ngpr]; \
481 ngpr += n; \
482 goto done; \
483 }
484 #else /* MIPS64 soft-float */
485 #define CALLBACK_HANDLE_REGARG \
486 if (ngpr + n <= maxgpr) { \
487 UNUSED(isfp); \
488 sp = (void*) &cts->cb.gpr[ngpr]; \
489 ngpr += n; \
490 goto done; \
491 }
492 #endif
493
494 #define CALLBACK_HANDLE_RET \
495 if (ctype_isfp(ctr->info) && ctr->size == sizeof(float)) \
496 ((float *)dp)[1] = *(float *)dp;
497
498 #else
499 #error "Missing calling convention definitions for this architecture"
500 #endif
501
502 /* Convert and push callback arguments to Lua stack. */
callback_conv_args(CTState * cts,lua_State * L)503 static void callback_conv_args(CTState *cts, lua_State *L)
504 {
505 TValue *o = L->top;
506 intptr_t *stack = cts->cb.stack;
507 MSize slot = cts->cb.slot;
508 CTypeID id = 0, rid, fid;
509 int gcsteps = 0;
510 CType *ct;
511 GCfunc *fn;
512 int fntp;
513 MSize ngpr = 0, nsp = 0, maxgpr = CCALL_NARG_GPR;
514 #if CCALL_NARG_FPR
515 MSize nfpr = 0;
516 #if LJ_TARGET_ARM
517 MSize fprodd = 0;
518 #endif
519 #endif
520
521 if (slot < cts->cb.sizeid && (id = cts->cb.cbid[slot]) != 0) {
522 ct = ctype_get(cts, id);
523 rid = ctype_cid(ct->info); /* Return type. x86: +(spadj<<16). */
524 fn = funcV(lj_tab_getint(cts->miscmap, (int32_t)slot));
525 fntp = LJ_TFUNC;
526 } else { /* Must set up frame first, before throwing the error. */
527 ct = NULL;
528 rid = 0;
529 fn = (GCfunc *)L;
530 fntp = LJ_TTHREAD;
531 }
532 /* Continuation returns from callback. */
533 if (LJ_FR2) {
534 (o++)->u64 = LJ_CONT_FFI_CALLBACK;
535 (o++)->u64 = rid;
536 o++;
537 } else {
538 o->u32.lo = LJ_CONT_FFI_CALLBACK;
539 o->u32.hi = rid;
540 o++;
541 }
542 setframe_gc(o, obj2gco(fn), fntp);
543 setframe_ftsz(o, ((char *)(o+1) - (char *)L->base) + FRAME_CONT);
544 L->top = L->base = ++o;
545 if (!ct)
546 lj_err_caller(cts->L, LJ_ERR_FFI_BADCBACK);
547 if (isluafunc(fn))
548 setcframe_pc(L->cframe, proto_bc(funcproto(fn))+1);
549 lj_state_checkstack(L, LUA_MINSTACK); /* May throw. */
550 o = L->base; /* Might have been reallocated. */
551
552 #if LJ_TARGET_X86
553 /* x86 has several different calling conventions. */
554 switch (ctype_cconv(ct->info)) {
555 case CTCC_FASTCALL: maxgpr = 2; break;
556 case CTCC_THISCALL: maxgpr = 1; break;
557 default: maxgpr = 0; break;
558 }
559 #endif
560
561 fid = ct->sib;
562 while (fid) {
563 CType *ctf = ctype_get(cts, fid);
564 if (!ctype_isattrib(ctf->info)) {
565 CType *cta;
566 void *sp;
567 CTSize sz;
568 int isfp;
569 MSize n;
570 lua_assert(ctype_isfield(ctf->info));
571 cta = ctype_rawchild(cts, ctf);
572 isfp = ctype_isfp(cta->info);
573 sz = (cta->size + CTSIZE_PTR-1) & ~(CTSIZE_PTR-1);
574 n = sz / CTSIZE_PTR; /* Number of GPRs or stack slots needed. */
575
576 CALLBACK_HANDLE_REGARG /* Handle register arguments. */
577
578 /* Otherwise pass argument on stack. */
579 if (CCALL_ALIGN_STACKARG && LJ_32 && sz == 8)
580 nsp = (nsp + 1) & ~1u; /* Align 64 bit argument on stack. */
581 sp = &stack[nsp];
582 nsp += n;
583
584 done:
585 if (LJ_BE && cta->size < CTSIZE_PTR
586 #if LJ_TARGET_MIPS64
587 && !(isfp && nsp)
588 #endif
589 )
590 sp = (void *)((uint8_t *)sp + CTSIZE_PTR-cta->size);
591 gcsteps += lj_cconv_tv_ct(cts, cta, 0, o++, sp);
592 }
593 fid = ctf->sib;
594 }
595 L->top = o;
596 #if LJ_TARGET_X86
597 /* Store stack adjustment for returns from non-cdecl callbacks. */
598 if (ctype_cconv(ct->info) != CTCC_CDECL) {
599 #if LJ_FR2
600 (L->base-3)->u64 |= (nsp << (16+2));
601 #else
602 (L->base-2)->u32.hi |= (nsp << (16+2));
603 #endif
604 }
605 #endif
606 while (gcsteps-- > 0)
607 lj_gc_check(L);
608 }
609
610 /* Convert Lua object to callback result. */
callback_conv_result(CTState * cts,lua_State * L,TValue * o)611 static void callback_conv_result(CTState *cts, lua_State *L, TValue *o)
612 {
613 #if LJ_FR2
614 CType *ctr = ctype_raw(cts, (uint16_t)(L->base-3)->u64);
615 #else
616 CType *ctr = ctype_raw(cts, (uint16_t)(L->base-2)->u32.hi);
617 #endif
618 #if LJ_TARGET_X86
619 cts->cb.gpr[2] = 0;
620 #endif
621 if (!ctype_isvoid(ctr->info)) {
622 uint8_t *dp = (uint8_t *)&cts->cb.gpr[0];
623 #if CCALL_NUM_FPR
624 if (ctype_isfp(ctr->info))
625 dp = (uint8_t *)&cts->cb.fpr[0];
626 #endif
627 lj_cconv_ct_tv(cts, ctr, dp, o, 0);
628 #ifdef CALLBACK_HANDLE_RET
629 CALLBACK_HANDLE_RET
630 #endif
631 /* Extend returned integers to (at least) 32 bits. */
632 if (ctype_isinteger_or_bool(ctr->info) && ctr->size < 4) {
633 if (ctr->info & CTF_UNSIGNED)
634 *(uint32_t *)dp = ctr->size == 1 ? (uint32_t)*(uint8_t *)dp :
635 (uint32_t)*(uint16_t *)dp;
636 else
637 *(int32_t *)dp = ctr->size == 1 ? (int32_t)*(int8_t *)dp :
638 (int32_t)*(int16_t *)dp;
639 }
640 #if LJ_TARGET_MIPS64
641 /* Always sign-extend results to 64 bits. Even a soft-fp 'float'. */
642 if (ctr->size <= 4 &&
643 (LJ_ABI_SOFTFP || ctype_isinteger_or_bool(ctr->info)))
644 *(int64_t *)dp = (int64_t)*(int32_t *)dp;
645 #endif
646 #if LJ_TARGET_X86
647 if (ctype_isfp(ctr->info))
648 cts->cb.gpr[2] = ctr->size == sizeof(float) ? 1 : 2;
649 #endif
650 }
651 }
652
653 /* Enter callback. */
lj_ccallback_enter(CTState * cts,void * cf)654 lua_State * LJ_FASTCALL lj_ccallback_enter(CTState *cts, void *cf)
655 {
656 lua_State *L = cts->L;
657 global_State *g = cts->g;
658 lua_assert(L != NULL);
659 if (tvref(g->jit_base)) {
660 setstrV(L, L->top++, lj_err_str(L, LJ_ERR_FFI_BADCBACK));
661 if (g->panic) g->panic(L);
662 exit(EXIT_FAILURE);
663 }
664 lj_trace_abort(g); /* Never record across callback. */
665 /* Setup C frame. */
666 cframe_prev(cf) = L->cframe;
667 setcframe_L(cf, L);
668 cframe_errfunc(cf) = -1;
669 cframe_nres(cf) = 0;
670 L->cframe = cf;
671 callback_conv_args(cts, L);
672 return L; /* Now call the function on this stack. */
673 }
674
675 /* Leave callback. */
lj_ccallback_leave(CTState * cts,TValue * o)676 void LJ_FASTCALL lj_ccallback_leave(CTState *cts, TValue *o)
677 {
678 lua_State *L = cts->L;
679 GCfunc *fn;
680 TValue *obase = L->base;
681 L->base = L->top; /* Keep continuation frame for throwing errors. */
682 if (o >= L->base) {
683 /* PC of RET* is lost. Point to last line for result conv. errors. */
684 fn = curr_func(L);
685 if (isluafunc(fn)) {
686 GCproto *pt = funcproto(fn);
687 setcframe_pc(L->cframe, proto_bc(pt)+pt->sizebc+1);
688 }
689 }
690 callback_conv_result(cts, L, o);
691 /* Finally drop C frame and continuation frame. */
692 L->top -= 2+2*LJ_FR2;
693 L->base = obase;
694 L->cframe = cframe_prev(L->cframe);
695 cts->cb.slot = 0; /* Blacklist C function that called the callback. */
696 }
697
698 /* -- C callback management ----------------------------------------------- */
699
700 /* Get an unused slot in the callback slot table. */
callback_slot_new(CTState * cts,CType * ct)701 static MSize callback_slot_new(CTState *cts, CType *ct)
702 {
703 CTypeID id = ctype_typeid(cts, ct);
704 CTypeID1 *cbid = cts->cb.cbid;
705 MSize top;
706 for (top = cts->cb.topid; top < cts->cb.sizeid; top++)
707 if (LJ_LIKELY(cbid[top] == 0))
708 goto found;
709 #if CALLBACK_MAX_SLOT
710 if (top >= CALLBACK_MAX_SLOT)
711 #endif
712 lj_err_caller(cts->L, LJ_ERR_FFI_CBACKOV);
713 if (!cts->cb.mcode)
714 callback_mcode_new(cts);
715 lj_mem_growvec(cts->L, cbid, cts->cb.sizeid, CALLBACK_MAX_SLOT, CTypeID1);
716 cts->cb.cbid = cbid;
717 memset(cbid+top, 0, (cts->cb.sizeid-top)*sizeof(CTypeID1));
718 found:
719 cbid[top] = id;
720 cts->cb.topid = top+1;
721 return top;
722 }
723
724 /* Check for function pointer and supported argument/result types. */
callback_checkfunc(CTState * cts,CType * ct)725 static CType *callback_checkfunc(CTState *cts, CType *ct)
726 {
727 int narg = 0;
728 if (!ctype_isptr(ct->info) || (LJ_64 && ct->size != CTSIZE_PTR))
729 return NULL;
730 ct = ctype_rawchild(cts, ct);
731 if (ctype_isfunc(ct->info)) {
732 CType *ctr = ctype_rawchild(cts, ct);
733 CTypeID fid = ct->sib;
734 if (!(ctype_isvoid(ctr->info) || ctype_isenum(ctr->info) ||
735 ctype_isptr(ctr->info) || (ctype_isnum(ctr->info) && ctr->size <= 8)))
736 return NULL;
737 if ((ct->info & CTF_VARARG))
738 return NULL;
739 while (fid) {
740 CType *ctf = ctype_get(cts, fid);
741 if (!ctype_isattrib(ctf->info)) {
742 CType *cta;
743 lua_assert(ctype_isfield(ctf->info));
744 cta = ctype_rawchild(cts, ctf);
745 if (!(ctype_isenum(cta->info) || ctype_isptr(cta->info) ||
746 (ctype_isnum(cta->info) && cta->size <= 8)) ||
747 ++narg >= LUA_MINSTACK-3)
748 return NULL;
749 }
750 fid = ctf->sib;
751 }
752 return ct;
753 }
754 return NULL;
755 }
756
757 /* Create a new callback and return the callback function pointer. */
lj_ccallback_new(CTState * cts,CType * ct,GCfunc * fn)758 void *lj_ccallback_new(CTState *cts, CType *ct, GCfunc *fn)
759 {
760 ct = callback_checkfunc(cts, ct);
761 if (ct) {
762 MSize slot = callback_slot_new(cts, ct);
763 GCtab *t = cts->miscmap;
764 setfuncV(cts->L, lj_tab_setint(cts->L, t, (int32_t)slot), fn);
765 lj_gc_anybarriert(cts->L, t);
766 return callback_slot2ptr(cts, slot);
767 }
768 return NULL; /* Bad conversion. */
769 }
770
771 #endif
772