1 /* -----------------------------------------------------------------------
2 ffiw64.c - Copyright (c) 2018 Anthony Green
3 Copyright (c) 2014 Red Hat, Inc.
4
5 x86 win64 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 #if defined(__x86_64__) || defined(_M_AMD64)
29 #include <ffi.h>
30 #include <ffi_common.h>
31 #include <stdlib.h>
32 #include <stdint.h>
33
34 #ifdef X86_WIN64
35 #define EFI64(name) name
36 #else
37 #define EFI64(name) FFI_HIDDEN name##_efi64
38 #endif
39
40 struct win64_call_frame
41 {
42 UINT64 rbp; /* 0 */
43 UINT64 retaddr; /* 8 */
44 UINT64 fn; /* 16 */
45 UINT64 flags; /* 24 */
46 UINT64 rvalue; /* 32 */
47 };
48
49 extern void ffi_call_win64 (void *stack, struct win64_call_frame *,
50 void *closure) FFI_HIDDEN;
51
52 ffi_status FFI_HIDDEN
53 EFI64(ffi_prep_cif_machdep)(ffi_cif *cif)
54 {
55 int flags, n;
56
57 switch (cif->abi)
58 {
59 case FFI_WIN64:
60 case FFI_GNUW64:
61 break;
62 default:
63 return FFI_BAD_ABI;
64 }
65
66 flags = cif->rtype->type;
67 switch (flags)
68 {
69 default:
70 break;
71 case FFI_TYPE_LONGDOUBLE:
72 /* GCC returns long double values by reference, like a struct */
73 if (cif->abi == FFI_GNUW64)
74 flags = FFI_TYPE_STRUCT;
75 break;
76 case FFI_TYPE_COMPLEX:
77 flags = FFI_TYPE_STRUCT;
78 /* FALLTHRU */
79 case FFI_TYPE_STRUCT:
80 switch (cif->rtype->size)
81 {
82 case 8:
83 flags = FFI_TYPE_UINT64;
84 break;
85 case 4:
86 flags = FFI_TYPE_SMALL_STRUCT_4B;
87 break;
88 case 2:
89 flags = FFI_TYPE_SMALL_STRUCT_2B;
90 break;
91 case 1:
92 flags = FFI_TYPE_SMALL_STRUCT_1B;
93 break;
94 }
95 break;
96 }
97 cif->flags = flags;
98
99 /* Each argument either fits in a register, an 8 byte slot, or is
100 passed by reference with the pointer in the 8 byte slot. */
101 n = cif->nargs;
102 n += (flags == FFI_TYPE_STRUCT);
103 if (n < 4)
104 n = 4;
105 cif->bytes = n * 8;
106
107 return FFI_OK;
108 }
109
110 static void
111 ffi_call_int (ffi_cif *cif, void (*fn)(void), void *rvalue,
112 void **avalue, void *closure)
113 {
114 int i, j, n, flags;
115 UINT64 *stack;
116 size_t rsize;
117 struct win64_call_frame *frame;
118
119 FFI_ASSERT(cif->abi == FFI_GNUW64 || cif->abi == FFI_WIN64);
120
121 flags = cif->flags;
122 rsize = 0;
123
124 /* If we have no return value for a structure, we need to create one.
125 Otherwise we can ignore the return type entirely. */
126 if (rvalue == NULL)
127 {
128 if (flags == FFI_TYPE_STRUCT)
129 rsize = cif->rtype->size;
130 else
131 flags = FFI_TYPE_VOID;
132 }
133
134 stack = alloca(cif->bytes + sizeof(struct win64_call_frame) + rsize);
135 frame = (struct win64_call_frame *)((char *)stack + cif->bytes);
136 if (rsize)
137 rvalue = frame + 1;
138
139 frame->fn = (uintptr_t)fn;
140 frame->flags = flags;
141 frame->rvalue = (uintptr_t)rvalue;
142
143 j = 0;
144 if (flags == FFI_TYPE_STRUCT)
145 {
146 stack[0] = (uintptr_t)rvalue;
147 j = 1;
148 }
149
150 for (i = 0, n = cif->nargs; i < n; ++i, ++j)
151 {
152 switch (cif->arg_types[i]->size)
153 {
154 case 8:
155 stack[j] = *(UINT64 *)avalue[i];
156 break;
157 case 4:
158 stack[j] = *(UINT32 *)avalue[i];
159 break;
160 case 2:
161 stack[j] = *(UINT16 *)avalue[i];
162 break;
163 case 1:
164 stack[j] = *(UINT8 *)avalue[i];
165 break;
166 default:
167 stack[j] = (uintptr_t)avalue[i];
168 break;
169 }
170 }
171
172 ffi_call_win64 (stack, frame, closure);
173 }
174
175 void
176 EFI64(ffi_call)(ffi_cif *cif, void (*fn)(void), void *rvalue, void **avalue)
177 {
178 ffi_call_int (cif, fn, rvalue, avalue, NULL);
179 }
180
181 void
182 EFI64(ffi_call_go)(ffi_cif *cif, void (*fn)(void), void *rvalue,
183 void **avalue, void *closure)
184 {
185 ffi_call_int (cif, fn, rvalue, avalue, closure);
186 }
187
188
189 extern void ffi_closure_win64(void) FFI_HIDDEN;
190 extern void ffi_go_closure_win64(void) FFI_HIDDEN;
191
192 ffi_status
193 EFI64(ffi_prep_closure_loc)(ffi_closure* closure,
194 ffi_cif* cif,
195 void (*fun)(ffi_cif*, void*, void**, void*),
196 void *user_data,
197 void *codeloc)
198 {
199 static const unsigned char trampoline[16] = {
200 /* leaq -0x7(%rip),%r10 # 0x0 */
201 0x4c, 0x8d, 0x15, 0xf9, 0xff, 0xff, 0xff,
202 /* jmpq *0x3(%rip) # 0x10 */
203 0xff, 0x25, 0x03, 0x00, 0x00, 0x00,
204 /* nopl (%rax) */
205 0x0f, 0x1f, 0x00
206 };
207 char *tramp = closure->tramp;
208
209 switch (cif->abi)
210 {
211 case FFI_WIN64:
212 case FFI_GNUW64:
213 break;
214 default:
215 return FFI_BAD_ABI;
216 }
217
218 memcpy (tramp, trampoline, sizeof(trampoline));
219 *(UINT64 *)(tramp + 16) = (uintptr_t)ffi_closure_win64;
220
221 closure->cif = cif;
222 closure->fun = fun;
223 closure->user_data = user_data;
224
225 return FFI_OK;
226 }
227
228 ffi_status
229 EFI64(ffi_prep_go_closure)(ffi_go_closure* closure, ffi_cif* cif,
230 void (*fun)(ffi_cif*, void*, void**, void*))
231 {
232 switch (cif->abi)
233 {
234 case FFI_WIN64:
235 case FFI_GNUW64:
236 break;
237 default:
238 return FFI_BAD_ABI;
239 }
240
241 closure->tramp = ffi_go_closure_win64;
242 closure->cif = cif;
243 closure->fun = fun;
244
245 return FFI_OK;
246 }
247
248 struct win64_closure_frame
249 {
250 UINT64 rvalue[2];
251 UINT64 fargs[4];
252 UINT64 retaddr;
253 UINT64 args[];
254 };
255
256 /* Force the inner function to use the MS ABI. When compiling on win64
257 this is a nop. When compiling on unix, this simplifies the assembly,
258 and places the burden of saving the extra call-saved registers on
259 the compiler. */
260 int FFI_HIDDEN __attribute__((ms_abi))
261 ffi_closure_win64_inner(ffi_cif *cif,
262 void (*fun)(ffi_cif*, void*, void**, void*),
263 void *user_data,
264 struct win64_closure_frame *frame)
265 {
266 void **avalue;
267 void *rvalue;
268 int i, n, nreg, flags;
269
270 avalue = alloca(cif->nargs * sizeof(void *));
271 rvalue = frame->rvalue;
272 nreg = 0;
273
274 /* When returning a structure, the address is in the first argument.
275 We must also be prepared to return the same address in eax, so
276 install that address in the frame and pretend we return a pointer. */
277 flags = cif->flags;
278 if (flags == FFI_TYPE_STRUCT)
279 {
280 rvalue = (void *)(uintptr_t)frame->args[0];
281 frame->rvalue[0] = frame->args[0];
282 nreg = 1;
283 }
284
285 for (i = 0, n = cif->nargs; i < n; ++i, ++nreg)
286 {
287 size_t size = cif->arg_types[i]->size;
288 size_t type = cif->arg_types[i]->type;
289 void *a;
290
291 if (type == FFI_TYPE_DOUBLE || type == FFI_TYPE_FLOAT)
292 {
293 if (nreg < 4)
294 a = &frame->fargs[nreg];
295 else
296 a = &frame->args[nreg];
297 }
298 else if (size == 1 || size == 2 || size == 4 || size == 8)
299 a = &frame->args[nreg];
300 else
301 a = (void *)(uintptr_t)frame->args[nreg];
302
303 avalue[i] = a;
304 }
305
306 /* Invoke the closure. */
307 fun (cif, rvalue, avalue, user_data);
308 return flags;
309 }
310
311 #endif /* __x86_64__ */