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use readdir_r instead of readdir for reentrancy
[qemu/kevin.git] / linux-user / vm86.c
blob0b2439dfa3cb594c5e0c5b68cddb98ae7d1f6579
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 <stdlib.h>
20 #include <stdio.h>
21 #include <stdarg.h>
22 #include <string.h>
23 #include <errno.h>
24 #include <unistd.h>
25
26 #include "qemu.h"
27
28 //#define DEBUG_VM86
29
30 #ifdef DEBUG_VM86
31 # define LOG_VM86(...) qemu_log(__VA_ARGS__);
32 #else
33 # define LOG_VM86(...) do { } while (0)
34 #endif
35
36
37 #define set_flags(X,new,mask) \
38 ((X) = ((X) & ~(mask)) | ((new) & (mask)))
39
40 #define SAFE_MASK (0xDD5)
41 #define RETURN_MASK (0xDFF)
42
43 static inline int is_revectored(int nr, struct target_revectored_struct *bitmap)
44 {
45 return (((uint8_t *)bitmap)[nr >> 3] >> (nr & 7)) & 1;
46 }
47
48 static inline void vm_putw(uint32_t segptr, unsigned int reg16, unsigned int val)
49 {
50 stw(segptr + (reg16 & 0xffff), val);
51 }
52
53 static inline void vm_putl(uint32_t segptr, unsigned int reg16, unsigned int val)
54 {
55 stl(segptr + (reg16 & 0xffff), val);
56 }
57
58 static inline unsigned int vm_getb(uint32_t segptr, unsigned int reg16)
59 {
60 return ldub(segptr + (reg16 & 0xffff));
61 }
62
63 static inline unsigned int vm_getw(uint32_t segptr, unsigned int reg16)
64 {
65 return lduw(segptr + (reg16 & 0xffff));
66 }
67
68 static inline unsigned int vm_getl(uint32_t segptr, unsigned int reg16)
69 {
70 return ldl(segptr + (reg16 & 0xffff));
71 }
72
73 void save_v86_state(CPUX86State *env)
74 {
75 TaskState *ts = env->opaque;
76 struct target_vm86plus_struct * target_v86;
77
78 if (!lock_user_struct(VERIFY_WRITE, target_v86, ts->target_v86, 0))
79 /* FIXME - should return an error */
80 return;
81 /* put the VM86 registers in the userspace register structure */
82 target_v86->regs.eax = tswap32(env->regs[R_EAX]);
83 target_v86->regs.ebx = tswap32(env->regs[R_EBX]);
84 target_v86->regs.ecx = tswap32(env->regs[R_ECX]);
85 target_v86->regs.edx = tswap32(env->regs[R_EDX]);
86 target_v86->regs.esi = tswap32(env->regs[R_ESI]);
87 target_v86->regs.edi = tswap32(env->regs[R_EDI]);
88 target_v86->regs.ebp = tswap32(env->regs[R_EBP]);
89 target_v86->regs.esp = tswap32(env->regs[R_ESP]);
90 target_v86->regs.eip = tswap32(env->eip);
91 target_v86->regs.cs = tswap16(env->segs[R_CS].selector);
92 target_v86->regs.ss = tswap16(env->segs[R_SS].selector);
93 target_v86->regs.ds = tswap16(env->segs[R_DS].selector);
94 target_v86->regs.es = tswap16(env->segs[R_ES].selector);
95 target_v86->regs.fs = tswap16(env->segs[R_FS].selector);
96 target_v86->regs.gs = tswap16(env->segs[R_GS].selector);
97 set_flags(env->eflags, ts->v86flags, VIF_MASK | ts->v86mask);
98 target_v86->regs.eflags = tswap32(env->eflags);
99 unlock_user_struct(target_v86, ts->target_v86, 1);
100 LOG_VM86("save_v86_state: eflags=%08x cs:ip=%04x:%04x\n",
101 env->eflags, env->segs[R_CS].selector, env->eip);
102
103 /* restore 32 bit registers */
104 env->regs[R_EAX] = ts->vm86_saved_regs.eax;
105 env->regs[R_EBX] = ts->vm86_saved_regs.ebx;
106 env->regs[R_ECX] = ts->vm86_saved_regs.ecx;
107 env->regs[R_EDX] = ts->vm86_saved_regs.edx;
108 env->regs[R_ESI] = ts->vm86_saved_regs.esi;
109 env->regs[R_EDI] = ts->vm86_saved_regs.edi;
110 env->regs[R_EBP] = ts->vm86_saved_regs.ebp;
111 env->regs[R_ESP] = ts->vm86_saved_regs.esp;
112 env->eflags = ts->vm86_saved_regs.eflags;
113 env->eip = ts->vm86_saved_regs.eip;
114
115 cpu_x86_load_seg(env, R_CS, ts->vm86_saved_regs.cs);
116 cpu_x86_load_seg(env, R_SS, ts->vm86_saved_regs.ss);
117 cpu_x86_load_seg(env, R_DS, ts->vm86_saved_regs.ds);
118 cpu_x86_load_seg(env, R_ES, ts->vm86_saved_regs.es);
119 cpu_x86_load_seg(env, R_FS, ts->vm86_saved_regs.fs);
120 cpu_x86_load_seg(env, R_GS, ts->vm86_saved_regs.gs);
121 }
122
123 /* return from vm86 mode to 32 bit. The vm86() syscall will return
124 'retval' */
125 static inline void return_to_32bit(CPUX86State *env, int retval)
126 {
127 LOG_VM86("return_to_32bit: ret=0x%x\n", retval);
128 save_v86_state(env);
129 env->regs[R_EAX] = retval;
130 }
131
132 static inline int set_IF(CPUX86State *env)
133 {
134 TaskState *ts = env->opaque;
135
136 ts->v86flags |= VIF_MASK;
137 if (ts->v86flags & VIP_MASK) {
138 return_to_32bit(env, TARGET_VM86_STI);
139 return 1;
140 }
141 return 0;
142 }
143
144 static inline void clear_IF(CPUX86State *env)
145 {
146 TaskState *ts = env->opaque;
147
148 ts->v86flags &= ~VIF_MASK;
149 }
150
151 static inline void clear_TF(CPUX86State *env)
152 {
153 env->eflags &= ~TF_MASK;
154 }
155
156 static inline void clear_AC(CPUX86State *env)
157 {
158 env->eflags &= ~AC_MASK;
159 }
160
161 static inline int set_vflags_long(unsigned long eflags, CPUX86State *env)
162 {
163 TaskState *ts = env->opaque;
164
165 set_flags(ts->v86flags, eflags, ts->v86mask);
166 set_flags(env->eflags, eflags, SAFE_MASK);
167 if (eflags & IF_MASK)
168 return set_IF(env);
169 else
170 clear_IF(env);
171 return 0;
172 }
173
174 static inline int set_vflags_short(unsigned short flags, CPUX86State *env)
175 {
176 TaskState *ts = env->opaque;
177
178 set_flags(ts->v86flags, flags, ts->v86mask & 0xffff);
179 set_flags(env->eflags, flags, SAFE_MASK);
180 if (flags & IF_MASK)
181 return set_IF(env);
182 else
183 clear_IF(env);
184 return 0;
185 }
186
187 static inline unsigned int get_vflags(CPUX86State *env)
188 {
189 TaskState *ts = env->opaque;
190 unsigned int flags;
191
192 flags = env->eflags & RETURN_MASK;
193 if (ts->v86flags & VIF_MASK)
194 flags |= IF_MASK;
195 flags |= IOPL_MASK;
196 return flags | (ts->v86flags & ts->v86mask);
197 }
198
199 #define ADD16(reg, val) reg = (reg & ~0xffff) | ((reg + (val)) & 0xffff)
200
201 /* handle VM86 interrupt (NOTE: the CPU core currently does not
202 support TSS interrupt revectoring, so this code is always executed) */
203 static void do_int(CPUX86State *env, int intno)
204 {
205 TaskState *ts = env->opaque;
206 uint32_t int_addr, segoffs, ssp;
207 unsigned int sp;
208
209 if (env->segs[R_CS].selector == TARGET_BIOSSEG)
210 goto cannot_handle;
211 if (is_revectored(intno, &ts->vm86plus.int_revectored))
212 goto cannot_handle;
213 if (intno == 0x21 && is_revectored((env->regs[R_EAX] >> 8) & 0xff,
214 &ts->vm86plus.int21_revectored))
215 goto cannot_handle;
216 int_addr = (intno << 2);
217 segoffs = ldl(int_addr);
218 if ((segoffs >> 16) == TARGET_BIOSSEG)
219 goto cannot_handle;
220 LOG_VM86("VM86: emulating int 0x%x. CS:IP=%04x:%04x\n",
221 intno, segoffs >> 16, segoffs & 0xffff);
222 /* save old state */
223 ssp = env->segs[R_SS].selector << 4;
224 sp = env->regs[R_ESP] & 0xffff;
225 vm_putw(ssp, sp - 2, get_vflags(env));
226 vm_putw(ssp, sp - 4, env->segs[R_CS].selector);
227 vm_putw(ssp, sp - 6, env->eip);
228 ADD16(env->regs[R_ESP], -6);
229 /* goto interrupt handler */
230 env->eip = segoffs & 0xffff;
231 cpu_x86_load_seg(env, R_CS, segoffs >> 16);
232 clear_TF(env);
233 clear_IF(env);
234 clear_AC(env);
235 return;
236 cannot_handle:
237 LOG_VM86("VM86: return to 32 bits int 0x%x\n", intno);
238 return_to_32bit(env, TARGET_VM86_INTx | (intno << 8));
239 }
240
241 void handle_vm86_trap(CPUX86State *env, int trapno)
242 {
243 if (trapno == 1 || trapno == 3) {
244 return_to_32bit(env, TARGET_VM86_TRAP + (trapno << 8));
245 } else {
246 do_int(env, trapno);
247 }
248 }
249
250 #define CHECK_IF_IN_TRAP() \
251 if ((ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) && \
252 (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_TFpendig)) \
253 newflags |= TF_MASK
254
255 #define VM86_FAULT_RETURN \
256 if ((ts->vm86plus.vm86plus.flags & TARGET_force_return_for_pic) && \
257 (ts->v86flags & (IF_MASK | VIF_MASK))) \
258 return_to_32bit(env, TARGET_VM86_PICRETURN); \
259 return
260
261 void handle_vm86_fault(CPUX86State *env)
262 {
263 TaskState *ts = env->opaque;
264 uint32_t csp, ssp;
265 unsigned int ip, sp, newflags, newip, newcs, opcode, intno;
266 int data32, pref_done;
267
268 csp = env->segs[R_CS].selector << 4;
269 ip = env->eip & 0xffff;
270
271 ssp = env->segs[R_SS].selector << 4;
272 sp = env->regs[R_ESP] & 0xffff;
273
274 LOG_VM86("VM86 exception %04x:%08x\n",
275 env->segs[R_CS].selector, env->eip);
276
277 data32 = 0;
278 pref_done = 0;
279 do {
280 opcode = vm_getb(csp, ip);
281 ADD16(ip, 1);
282 switch (opcode) {
283 case 0x66: /* 32-bit data */ data32=1; break;
284 case 0x67: /* 32-bit address */ break;
285 case 0x2e: /* CS */ break;
286 case 0x3e: /* DS */ break;
287 case 0x26: /* ES */ break;
288 case 0x36: /* SS */ break;
289 case 0x65: /* GS */ break;
290 case 0x64: /* FS */ break;
291 case 0xf2: /* repnz */ break;
292 case 0xf3: /* rep */ break;
293 default: pref_done = 1;
294 }
295 } while (!pref_done);
296
297 /* VM86 mode */
298 switch(opcode) {
299 case 0x9c: /* pushf */
300 if (data32) {
301 vm_putl(ssp, sp - 4, get_vflags(env));
302 ADD16(env->regs[R_ESP], -4);
303 } else {
304 vm_putw(ssp, sp - 2, get_vflags(env));
305 ADD16(env->regs[R_ESP], -2);
306 }
307 env->eip = ip;
308 VM86_FAULT_RETURN;
309
310 case 0x9d: /* popf */
311 if (data32) {
312 newflags = vm_getl(ssp, sp);
313 ADD16(env->regs[R_ESP], 4);
314 } else {
315 newflags = vm_getw(ssp, sp);
316 ADD16(env->regs[R_ESP], 2);
317 }
318 env->eip = ip;
319 CHECK_IF_IN_TRAP();
320 if (data32) {
321 if (set_vflags_long(newflags, env))
322 return;
323 } else {
324 if (set_vflags_short(newflags, env))
325 return;
326 }
327 VM86_FAULT_RETURN;
328
329 case 0xcd: /* int */
330 intno = vm_getb(csp, ip);
331 ADD16(ip, 1);
332 env->eip = ip;
333 if (ts->vm86plus.vm86plus.flags & TARGET_vm86dbg_active) {
334 if ( (ts->vm86plus.vm86plus.vm86dbg_intxxtab[intno >> 3] >>
335 (intno &7)) & 1) {
336 return_to_32bit(env, TARGET_VM86_INTx + (intno << 8));
337 return;
338 }
339 }
340 do_int(env, intno);
341 break;
342
343 case 0xcf: /* iret */
344 if (data32) {
345 newip = vm_getl(ssp, sp) & 0xffff;
346 newcs = vm_getl(ssp, sp + 4) & 0xffff;
347 newflags = vm_getl(ssp, sp + 8);
348 ADD16(env->regs[R_ESP], 12);
349 } else {
350 newip = vm_getw(ssp, sp);
351 newcs = vm_getw(ssp, sp + 2);
352 newflags = vm_getw(ssp, sp + 4);
353 ADD16(env->regs[R_ESP], 6);
354 }
355 env->eip = newip;
356 cpu_x86_load_seg(env, R_CS, newcs);
357 CHECK_IF_IN_TRAP();
358 if (data32) {
359 if (set_vflags_long(newflags, env))
360 return;
361 } else {
362 if (set_vflags_short(newflags, env))
363 return;
364 }
365 VM86_FAULT_RETURN;
366
367 case 0xfa: /* cli */
368 env->eip = ip;
369 clear_IF(env);
370 VM86_FAULT_RETURN;
371
372 case 0xfb: /* sti */
373 env->eip = ip;
374 if (set_IF(env))
375 return;
376 VM86_FAULT_RETURN;
377
378 default:
379 /* real VM86 GPF exception */
380 return_to_32bit(env, TARGET_VM86_UNKNOWN);
381 break;
382 }
383 }
384
385 int do_vm86(CPUX86State *env, long subfunction, abi_ulong vm86_addr)
386 {
387 TaskState *ts = env->opaque;
388 struct target_vm86plus_struct * target_v86;
389 int ret;
390
391 switch (subfunction) {
392 case TARGET_VM86_REQUEST_IRQ:
393 case TARGET_VM86_FREE_IRQ:
394 case TARGET_VM86_GET_IRQ_BITS:
395 case TARGET_VM86_GET_AND_RESET_IRQ:
396 gemu_log("qemu: unsupported vm86 subfunction (%ld)\n", subfunction);
397 ret = -TARGET_EINVAL;
398 goto out;
399 case TARGET_VM86_PLUS_INSTALL_CHECK:
400 /* NOTE: on old vm86 stuff this will return the error
401 from verify_area(), because the subfunction is
402 interpreted as (invalid) address to vm86_struct.
403 So the installation check works.
404 */
405 ret = 0;
406 goto out;
407 }
408
409 /* save current CPU regs */
410 ts->vm86_saved_regs.eax = 0; /* default vm86 syscall return code */
411 ts->vm86_saved_regs.ebx = env->regs[R_EBX];
412 ts->vm86_saved_regs.ecx = env->regs[R_ECX];
413 ts->vm86_saved_regs.edx = env->regs[R_EDX];
414 ts->vm86_saved_regs.esi = env->regs[R_ESI];
415 ts->vm86_saved_regs.edi = env->regs[R_EDI];
416 ts->vm86_saved_regs.ebp = env->regs[R_EBP];
417 ts->vm86_saved_regs.esp = env->regs[R_ESP];
418 ts->vm86_saved_regs.eflags = env->eflags;
419 ts->vm86_saved_regs.eip = env->eip;
420 ts->vm86_saved_regs.cs = env->segs[R_CS].selector;
421 ts->vm86_saved_regs.ss = env->segs[R_SS].selector;
422 ts->vm86_saved_regs.ds = env->segs[R_DS].selector;
423 ts->vm86_saved_regs.es = env->segs[R_ES].selector;
424 ts->vm86_saved_regs.fs = env->segs[R_FS].selector;
425 ts->vm86_saved_regs.gs = env->segs[R_GS].selector;
426
427 ts->target_v86 = vm86_addr;
428 if (!lock_user_struct(VERIFY_READ, target_v86, vm86_addr, 1))
429 return -TARGET_EFAULT;
430 /* build vm86 CPU state */
431 ts->v86flags = tswap32(target_v86->regs.eflags);
432 env->eflags = (env->eflags & ~SAFE_MASK) |
433 (tswap32(target_v86->regs.eflags) & SAFE_MASK) | VM_MASK;
434
435 ts->vm86plus.cpu_type = tswapl(target_v86->cpu_type);
436 switch (ts->vm86plus.cpu_type) {
437 case TARGET_CPU_286:
438 ts->v86mask = 0;
439 break;
440 case TARGET_CPU_386:
441 ts->v86mask = NT_MASK | IOPL_MASK;
442 break;
443 case TARGET_CPU_486:
444 ts->v86mask = AC_MASK | NT_MASK | IOPL_MASK;
445 break;
446 default:
447 ts->v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK;
448 break;
449 }
450
451 env->regs[R_EBX] = tswap32(target_v86->regs.ebx);
452 env->regs[R_ECX] = tswap32(target_v86->regs.ecx);
453 env->regs[R_EDX] = tswap32(target_v86->regs.edx);
454 env->regs[R_ESI] = tswap32(target_v86->regs.esi);
455 env->regs[R_EDI] = tswap32(target_v86->regs.edi);
456 env->regs[R_EBP] = tswap32(target_v86->regs.ebp);
457 env->regs[R_ESP] = tswap32(target_v86->regs.esp);
458 env->eip = tswap32(target_v86->regs.eip);
459 cpu_x86_load_seg(env, R_CS, tswap16(target_v86->regs.cs));
460 cpu_x86_load_seg(env, R_SS, tswap16(target_v86->regs.ss));
461 cpu_x86_load_seg(env, R_DS, tswap16(target_v86->regs.ds));
462 cpu_x86_load_seg(env, R_ES, tswap16(target_v86->regs.es));
463 cpu_x86_load_seg(env, R_FS, tswap16(target_v86->regs.fs));
464 cpu_x86_load_seg(env, R_GS, tswap16(target_v86->regs.gs));
465 ret = tswap32(target_v86->regs.eax); /* eax will be restored at
466 the end of the syscall */
467 memcpy(&ts->vm86plus.int_revectored,
468 &target_v86->int_revectored, 32);
469 memcpy(&ts->vm86plus.int21_revectored,
470 &target_v86->int21_revectored, 32);
471 ts->vm86plus.vm86plus.flags = tswapl(target_v86->vm86plus.flags);
472 memcpy(&ts->vm86plus.vm86plus.vm86dbg_intxxtab,
473 target_v86->vm86plus.vm86dbg_intxxtab, 32);
474 unlock_user_struct(target_v86, vm86_addr, 0);
475
476 LOG_VM86("do_vm86: cs:ip=%04x:%04x\n",
477 env->segs[R_CS].selector, env->eip);
478 /* now the virtual CPU is ready for vm86 execution ! */
479 out:
480 return ret;
481 }
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