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hw/pci: Have safer pcie_bus_realize() by checking error path
[qemu/ar7.git] / linux-user / vm86.c
blob4412522c4c4eb743a2573e9d01f2378bfa7bec42
1 /*
2 * vm86 linux syscall support
3 *
4 * Copyright (c) 2003 Fabrice Bellard
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, see <http://www.gnu.org/licenses/>.
18 */
19 #include "qemu/osdep.h"
20
21 #include "qemu.h"
22
23 //#define DEBUG_VM86
24
25 #ifdef DEBUG_VM86
26 # define LOG_VM86(...) qemu_log(__VA_ARGS__);
27 #else
28 # define LOG_VM86(...) do { } while (0)
29 #endif
30
31
32 #define set_flags(X,new,mask) \
33 ((X) = ((X) & ~(mask)) | ((new) & (mask)))
34
35 #define SAFE_MASK (0xDD5)
36 #define RETURN_MASK (0xDFF)
37
38 static inline int is_revectored(int nr, struct target_revectored_struct *bitmap)
39 {
40 return (((uint8_t *)bitmap)[nr >> 3] >> (nr & 7)) & 1;
41 }
42
43 static inline void vm_putw(CPUX86State *env, uint32_t segptr,
44 unsigned int reg16, unsigned int val)
45 {
46 cpu_stw_data(env, segptr + (reg16 & 0xffff), val);
47 }
48
49 static inline void vm_putl(CPUX86State *env, uint32_t segptr,
50 unsigned int reg16, unsigned int val)
51 {
52 cpu_stl_data(env, segptr + (reg16 & 0xffff), val);
53 }
54
55 static inline unsigned int vm_getb(CPUX86State *env,
56 uint32_t segptr, unsigned int reg16)
57 {
58 return cpu_ldub_data(env, segptr + (reg16 & 0xffff));
59 }
60
61 static inline unsigned int vm_getw(CPUX86State *env,
62 uint32_t segptr, unsigned int reg16)
63 {
64 return cpu_lduw_data(env, segptr + (reg16 & 0xffff));
65 }
66
67 static inline unsigned int vm_getl(CPUX86State *env,
68 uint32_t segptr, unsigned int reg16)
69 {
70 return cpu_ldl_data(env, segptr + (reg16 & 0xffff));
71 }
72
73 void save_v86_state(CPUX86State *env)
74 {
75 CPUState *cs = env_cpu(env);
76 TaskState *ts = cs->opaque;
77 struct target_vm86plus_struct * target_v86;
78
79 if (!lock_user_struct(VERIFY_WRITE, target_v86, ts->target_v86, 0))
80 /* FIXME - should return an error */
81 return;
82 /* put the VM86 registers in the userspace register structure */
83 target_v86->regs.eax = tswap32(env->regs[R_EAX]);
84 target_v86->regs.ebx = tswap32(env->regs[R_EBX]);
85 target_v86->regs.ecx = tswap32(env->regs[R_ECX]);
86 target_v86->regs.edx = tswap32(env->regs[R_EDX]);
87 target_v86->regs.esi = tswap32(env->regs[R_ESI]);
88 target_v86->regs.edi = tswap32(env->regs[R_EDI]);
89 target_v86->regs.ebp = tswap32(env->regs[R_EBP]);
90 target_v86->regs.esp = tswap32(env->regs[R_ESP]);
91 target_v86->regs.eip = tswap32(env->eip);
92 target_v86->regs.cs = tswap16(env->segs[R_CS].selector);
93 target_v86->regs.ss = tswap16(env->segs[R_SS].selector);
94 target_v86->regs.ds = tswap16(env->segs[R_DS].selector);
95 target_v86->regs.es = tswap16(env->segs[R_ES].selector);
96 target_v86->regs.fs = tswap16(env->segs[R_FS].selector);
97 target_v86->regs.gs = tswap16(env->segs[R_GS].selector);
98 set_flags(env->eflags, ts->v86flags, VIF_MASK | ts->v86mask);
99 target_v86->regs.eflags = tswap32(env->eflags);
100 unlock_user_struct(target_v86, ts->target_v86, 1);
101 LOG_VM86("save_v86_state: eflags=%08x cs:ip=%04x:%04x\n",
102 env->eflags, env->segs[R_CS].selector, env->eip);
103
104 /* restore 32 bit registers */
105 env->regs[R_EAX] = ts->vm86_saved_regs.eax;
106 env->regs[R_EBX] = ts->vm86_saved_regs.ebx;
107 env->regs[R_ECX] = ts->vm86_saved_regs.ecx;
108 env->regs[R_EDX] = ts->vm86_saved_regs.edx;
109 env->regs[R_ESI] = ts->vm86_saved_regs.esi;
110 env->regs[R_EDI] = ts->vm86_saved_regs.edi;
111 env->regs[R_EBP] = ts->vm86_saved_regs.ebp;
112 env->regs[R_ESP] = ts->vm86_saved_regs.esp;
113 env->eflags = ts->vm86_saved_regs.eflags;
114 env->eip = ts->vm86_saved_regs.eip;
115
116 cpu_x86_load_seg(env, R_CS, ts->vm86_saved_regs.cs);
117 cpu_x86_load_seg(env, R_SS, ts->vm86_saved_regs.ss);
118 cpu_x86_load_seg(env, R_DS, ts->vm86_saved_regs.ds);
119 cpu_x86_load_seg(env, R_ES, ts->vm86_saved_regs.es);
120 cpu_x86_load_seg(env, R_FS, ts->vm86_saved_regs.fs);
121 cpu_x86_load_seg(env, R_GS, ts->vm86_saved_regs.gs);
122 }
123
124 /* return from vm86 mode to 32 bit. The vm86() syscall will return
125 'retval' */
126 static inline void return_to_32bit(CPUX86State *env, int retval)
127 {
128 LOG_VM86("return_to_32bit: ret=0x%x\n", retval);
129 save_v86_state(env);
130 env->regs[R_EAX] = retval;
131 }
132
133 static inline int set_IF(CPUX86State *env)
134 {
135 CPUState *cs = env_cpu(env);
136 TaskState *ts = cs->opaque;
137
138 ts->v86flags |= VIF_MASK;
139 if (ts->v86flags & VIP_MASK) {
140 return_to_32bit(env, TARGET_VM86_STI);
141 return 1;
142 }
143 return 0;
144 }
145
146 static inline void clear_IF(CPUX86State *env)
147 {
148 CPUState *cs = env_cpu(env);
149 TaskState *ts = cs->opaque;
150
151 ts->v86flags &= ~VIF_MASK;
152 }
153
154 static inline void clear_TF(CPUX86State *env)
155 {
156 env->eflags &= ~TF_MASK;
157 }
158
159 static inline void clear_AC(CPUX86State *env)
160 {
161 env->eflags &= ~AC_MASK;
162 }
163
164 static inline int set_vflags_long(unsigned long eflags, CPUX86State *env)
165 {
166 CPUState *cs = env_cpu(env);
167 TaskState *ts = cs->opaque;
168
169 set_flags(ts->v86flags, eflags, ts->v86mask);
170 set_flags(env->eflags, eflags, SAFE_MASK);
171 if (eflags & IF_MASK)
172 return set_IF(env);
173 else
174 clear_IF(env);
175 return 0;
176 }
177
178 static inline int set_vflags_short(unsigned short flags, CPUX86State *env)
179 {
180 CPUState *cs = env_cpu(env);
181 TaskState *ts = cs->opaque;
182
183 set_flags(ts->v86flags, flags, ts->v86mask & 0xffff);
184 set_flags(env->eflags, flags, SAFE_MASK);
185 if (flags & IF_MASK)
186 return set_IF(env);
187 else
188 clear_IF(env);
189 return 0;
190 }
191
192 static inline unsigned int get_vflags(CPUX86State *env)
193 {
194 CPUState *cs = env_cpu(env);
195 TaskState *ts = cs->opaque;
196 unsigned int flags;
197
198 flags = env->eflags & RETURN_MASK;
199 if (ts->v86flags & VIF_MASK)
200 flags |= IF_MASK;
201 flags |= IOPL_MASK;
202 return flags | (ts->v86flags & ts->v86mask);
203 }
204
205 #define ADD16(reg, val) reg = (reg & ~0xffff) | ((reg + (val)) & 0xffff)
206
207 /* handle VM86 interrupt (NOTE: the CPU core currently does not
208 support TSS interrupt revectoring, so this code is always executed) */
209 static void do_int(CPUX86State *env, int intno)
210 {
211 CPUState *cs = env_cpu(env);
212 TaskState *ts = cs->opaque;
213 uint32_t int_addr, segoffs, ssp;
214 unsigned int sp;
215
216 if (env->segs[R_CS].selector == TARGET_BIOSSEG)
217 goto cannot_handle;
218 if (is_revectored(intno, &ts->vm86plus.int_revectored))
219 goto cannot_handle;
220 if (intno == 0x21 && is_revectored((env->regs[R_EAX] >> 8) & 0xff,
221 &ts->vm86plus.int21_revectored))
222 goto cannot_handle;
223 int_addr = (intno << 2);
224 segoffs = cpu_ldl_data(env, int_addr);
225 if ((segoffs >> 16) == TARGET_BIOSSEG)
226 goto cannot_handle;
227 LOG_VM86("VM86: emulating int 0x%x. CS:IP=%04x:%04x\n",
228 intno, segoffs >> 16, segoffs & 0xffff);
229 /* save old state */
230 ssp = env->segs[R_SS].selector << 4;
231 sp = env->regs[R_ESP] & 0xffff;
232 vm_putw(env, ssp, sp - 2, get_vflags(env));
233 vm_putw(env, ssp, sp - 4, env->segs[R_CS].selector);
234 vm_putw(env, ssp, sp - 6, env->eip);
235 ADD16(env->regs[R_ESP], -6);
236 /* goto interrupt handler */
237 env->eip = segoffs & 0xffff;
238 cpu_x86_load_seg(env, R_CS, segoffs >> 16);
239 clear_TF(env);
240 clear_IF(env);
241 clear_AC(env);
242 return;
243 cannot_handle:
244 LOG_VM86("VM86: return to 32 bits int 0x%x\n", intno);
245 return_to_32bit(env, TARGET_VM86_INTx | (intno << 8));
246 }
247
248 void handle_vm86_trap(CPUX86State *env, int trapno)
249 {
250 if (trapno == 1 || trapno == 3) {
251 return_to_32bit(env, TARGET_VM86_TRAP + (trapno << 8));
252 } else {
253 do_int(env, trapno);
254 }
255 }
256
257 #define CHECK_IF_IN_TRAP() \
258 if ((ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) && \
259 (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_TFpendig)) \
260 newflags |= TF_MASK
261
262 #define VM86_FAULT_RETURN \
263 if ((ts->vm86plus.vm86plus.flags & TARGET_force_return_for_pic) && \
264 (ts->v86flags & (IF_MASK | VIF_MASK))) \
265 return_to_32bit(env, TARGET_VM86_PICRETURN); \
266 return
267
268 void handle_vm86_fault(CPUX86State *env)
269 {
270 CPUState *cs = env_cpu(env);
271 TaskState *ts = cs->opaque;
272 uint32_t csp, ssp;
273 unsigned int ip, sp, newflags, newip, newcs, opcode, intno;
274 int data32, pref_done;
275
276 csp = env->segs[R_CS].selector << 4;
277 ip = env->eip & 0xffff;
278
279 ssp = env->segs[R_SS].selector << 4;
280 sp = env->regs[R_ESP] & 0xffff;
281
282 LOG_VM86("VM86 exception %04x:%08x\n",
283 env->segs[R_CS].selector, env->eip);
284
285 data32 = 0;
286 pref_done = 0;
287 do {
288 opcode = vm_getb(env, csp, ip);
289 ADD16(ip, 1);
290 switch (opcode) {
291 case 0x66: /* 32-bit data */ data32=1; break;
292 case 0x67: /* 32-bit address */ break;
293 case 0x2e: /* CS */ break;
294 case 0x3e: /* DS */ break;
295 case 0x26: /* ES */ break;
296 case 0x36: /* SS */ break;
297 case 0x65: /* GS */ break;
298 case 0x64: /* FS */ break;
299 case 0xf2: /* repnz */ break;
300 case 0xf3: /* rep */ break;
301 default: pref_done = 1;
302 }
303 } while (!pref_done);
304
305 /* VM86 mode */
306 switch(opcode) {
307 case 0x9c: /* pushf */
308 if (data32) {
309 vm_putl(env, ssp, sp - 4, get_vflags(env));
310 ADD16(env->regs[R_ESP], -4);
311 } else {
312 vm_putw(env, ssp, sp - 2, get_vflags(env));
313 ADD16(env->regs[R_ESP], -2);
314 }
315 env->eip = ip;
316 VM86_FAULT_RETURN;
317
318 case 0x9d: /* popf */
319 if (data32) {
320 newflags = vm_getl(env, ssp, sp);
321 ADD16(env->regs[R_ESP], 4);
322 } else {
323 newflags = vm_getw(env, ssp, sp);
324 ADD16(env->regs[R_ESP], 2);
325 }
326 env->eip = ip;
327 CHECK_IF_IN_TRAP();
328 if (data32) {
329 if (set_vflags_long(newflags, env))
330 return;
331 } else {
332 if (set_vflags_short(newflags, env))
333 return;
334 }
335 VM86_FAULT_RETURN;
336
337 case 0xcd: /* int */
338 intno = vm_getb(env, csp, ip);
339 ADD16(ip, 1);
340 env->eip = ip;
341 if (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) {
342 if ( (ts->vm86plus.vm86plus.vm86dbg_intxxtab[intno >> 3] >>
343 (intno &7)) & 1) {
344 return_to_32bit(env, TARGET_VM86_INTx + (intno << 8));
345 return;
346 }
347 }
348 do_int(env, intno);
349 break;
350
351 case 0xcf: /* iret */
352 if (data32) {
353 newip = vm_getl(env, ssp, sp) & 0xffff;
354 newcs = vm_getl(env, ssp, sp + 4) & 0xffff;
355 newflags = vm_getl(env, ssp, sp + 8);
356 ADD16(env->regs[R_ESP], 12);
357 } else {
358 newip = vm_getw(env, ssp, sp);
359 newcs = vm_getw(env, ssp, sp + 2);
360 newflags = vm_getw(env, ssp, sp + 4);
361 ADD16(env->regs[R_ESP], 6);
362 }
363 env->eip = newip;
364 cpu_x86_load_seg(env, R_CS, newcs);
365 CHECK_IF_IN_TRAP();
366 if (data32) {
367 if (set_vflags_long(newflags, env))
368 return;
369 } else {
370 if (set_vflags_short(newflags, env))
371 return;
372 }
373 VM86_FAULT_RETURN;
374
375 case 0xfa: /* cli */
376 env->eip = ip;
377 clear_IF(env);
378 VM86_FAULT_RETURN;
379
380 case 0xfb: /* sti */
381 env->eip = ip;
382 if (set_IF(env))
383 return;
384 VM86_FAULT_RETURN;
385
386 default:
387 /* real VM86 GPF exception */
388 return_to_32bit(env, TARGET_VM86_UNKNOWN);
389 break;
390 }
391 }
392
393 int do_vm86(CPUX86State *env, long subfunction, abi_ulong vm86_addr)
394 {
395 CPUState *cs = env_cpu(env);
396 TaskState *ts = cs->opaque;
397 struct target_vm86plus_struct * target_v86;
398 int ret;
399
400 switch (subfunction) {
401 case TARGET_VM86_REQUEST_IRQ:
402 case TARGET_VM86_FREE_IRQ:
403 case TARGET_VM86_GET_IRQ_BITS:
404 case TARGET_VM86_GET_AND_RESET_IRQ:
405 qemu_log_mask(LOG_UNIMP, "qemu: unsupported vm86 subfunction (%ld)\n",
406 subfunction);
407 ret = -TARGET_EINVAL;
408 goto out;
409 case TARGET_VM86_PLUS_INSTALL_CHECK:
410 /* NOTE: on old vm86 stuff this will return the error
411 from verify_area(), because the subfunction is
412 interpreted as (invalid) address to vm86_struct.
413 So the installation check works.
414 */
415 ret = 0;
416 goto out;
417 }
418
419 /* save current CPU regs */
420 ts->vm86_saved_regs.eax = 0; /* default vm86 syscall return code */
421 ts->vm86_saved_regs.ebx = env->regs[R_EBX];
422 ts->vm86_saved_regs.ecx = env->regs[R_ECX];
423 ts->vm86_saved_regs.edx = env->regs[R_EDX];
424 ts->vm86_saved_regs.esi = env->regs[R_ESI];
425 ts->vm86_saved_regs.edi = env->regs[R_EDI];
426 ts->vm86_saved_regs.ebp = env->regs[R_EBP];
427 ts->vm86_saved_regs.esp = env->regs[R_ESP];
428 ts->vm86_saved_regs.eflags = env->eflags;
429 ts->vm86_saved_regs.eip = env->eip;
430 ts->vm86_saved_regs.cs = env->segs[R_CS].selector;
431 ts->vm86_saved_regs.ss = env->segs[R_SS].selector;
432 ts->vm86_saved_regs.ds = env->segs[R_DS].selector;
433 ts->vm86_saved_regs.es = env->segs[R_ES].selector;
434 ts->vm86_saved_regs.fs = env->segs[R_FS].selector;
435 ts->vm86_saved_regs.gs = env->segs[R_GS].selector;
436
437 ts->target_v86 = vm86_addr;
438 if (!lock_user_struct(VERIFY_READ, target_v86, vm86_addr, 1))
439 return -TARGET_EFAULT;
440 /* build vm86 CPU state */
441 ts->v86flags = tswap32(target_v86->regs.eflags);
442 env->eflags = (env->eflags & ~SAFE_MASK) |
443 (tswap32(target_v86->regs.eflags) & SAFE_MASK) | VM_MASK;
444
445 ts->vm86plus.cpu_type = tswapal(target_v86->cpu_type);
446 switch (ts->vm86plus.cpu_type) {
447 case TARGET_CPU_286:
448 ts->v86mask = 0;
449 break;
450 case TARGET_CPU_386:
451 ts->v86mask = NT_MASK | IOPL_MASK;
452 break;
453 case TARGET_CPU_486:
454 ts->v86mask = AC_MASK | NT_MASK | IOPL_MASK;
455 break;
456 default:
457 ts->v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK;
458 break;
459 }
460
461 env->regs[R_EBX] = tswap32(target_v86->regs.ebx);
462 env->regs[R_ECX] = tswap32(target_v86->regs.ecx);
463 env->regs[R_EDX] = tswap32(target_v86->regs.edx);
464 env->regs[R_ESI] = tswap32(target_v86->regs.esi);
465 env->regs[R_EDI] = tswap32(target_v86->regs.edi);
466 env->regs[R_EBP] = tswap32(target_v86->regs.ebp);
467 env->regs[R_ESP] = tswap32(target_v86->regs.esp);
468 env->eip = tswap32(target_v86->regs.eip);
469 cpu_x86_load_seg(env, R_CS, tswap16(target_v86->regs.cs));
470 cpu_x86_load_seg(env, R_SS, tswap16(target_v86->regs.ss));
471 cpu_x86_load_seg(env, R_DS, tswap16(target_v86->regs.ds));
472 cpu_x86_load_seg(env, R_ES, tswap16(target_v86->regs.es));
473 cpu_x86_load_seg(env, R_FS, tswap16(target_v86->regs.fs));
474 cpu_x86_load_seg(env, R_GS, tswap16(target_v86->regs.gs));
475 ret = tswap32(target_v86->regs.eax); /* eax will be restored at
476 the end of the syscall */
477 memcpy(&ts->vm86plus.int_revectored,
478 &target_v86->int_revectored, 32);
479 memcpy(&ts->vm86plus.int21_revectored,
480 &target_v86->int21_revectored, 32);
481 ts->vm86plus.vm86plus.flags = tswapal(target_v86->vm86plus.flags);
482 memcpy(&ts->vm86plus.vm86plus.vm86dbg_intxxtab,
483 target_v86->vm86plus.vm86dbg_intxxtab, 32);
484 unlock_user_struct(target_v86, vm86_addr, 0);
485
486 LOG_VM86("do_vm86: cs:ip=%04x:%04x\n",
487 env->segs[R_CS].selector, env->eip);
488 /* now the virtual CPU is ready for vm86 execution ! */
489 out:
490 return ret;
491 }
AR7 emulation for QEMU