This source file includes following definitions.
- save_v86_state
- mark_screen_rdonly
- sys_vm86
- return_to_32bit
- set_IF
- clear_IF
- clear_TF
- set_vflags_long
- set_vflags_short
- get_vflags
- is_revectored
- do_int
- handle_vm86_debug
- handle_vm86_fault
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6 #include <linux/errno.h>
7 #include <linux/sched.h>
8 #include <linux/kernel.h>
9 #include <linux/signal.h>
10 #include <linux/string.h>
11 #include <linux/ptrace.h>
12 #include <linux/mm.h>
13
14 #include <asm/segment.h>
15 #include <asm/io.h>
16
17
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33
34
35 #define AL(regs) (((unsigned char *)&((regs)->eax))[0])
36 #define AH(regs) (((unsigned char *)&((regs)->eax))[1])
37 #define IP(regs) (*(unsigned short *)&((regs)->eip))
38 #define SP(regs) (*(unsigned short *)&((regs)->esp))
39
40
41
42
43 #define VFLAGS (*(unsigned short *)&(current->tss.v86flags))
44 #define VEFLAGS (current->tss.v86flags)
45
46 #define set_flags(X,new,mask) \
47 ((X) = ((X) & ~(mask)) | ((new) & (mask)))
48
49 #define SAFE_MASK (0xDD5)
50 #define RETURN_MASK (0xDFF)
51
52 asmlinkage struct pt_regs * save_v86_state(struct vm86_regs * regs)
53 {
54 unsigned long tmp;
55
56 if (!current->tss.vm86_info) {
57 printk("no vm86_info: BAD\n");
58 do_exit(SIGSEGV);
59 }
60 set_flags(regs->eflags, VEFLAGS, VIF_MASK | current->tss.v86mask);
61 memcpy_tofs(¤t->tss.vm86_info->regs,regs,sizeof(*regs));
62 put_fs_long(current->tss.screen_bitmap,¤t->tss.vm86_info->screen_bitmap);
63 tmp = current->tss.esp0;
64 current->tss.esp0 = current->saved_kernel_stack;
65 current->saved_kernel_stack = 0;
66 return (struct pt_regs *) tmp;
67 }
68
69 static void mark_screen_rdonly(struct task_struct * tsk)
70 {
71 pgd_t *pg_dir;
72
73 pg_dir = PAGE_DIR_OFFSET(tsk, 0);
74 if (!pgd_none(*pg_dir)) {
75 pte_t *pg_table;
76 int i;
77
78 if (pgd_bad(*pg_dir)) {
79 printk("vm86: bad page table directory entry %08lx\n", pgd_val(*pg_dir));
80 pgd_clear(pg_dir);
81 return;
82 }
83 pg_table = (pte_t *) pgd_page(*pg_dir);
84 pg_table += 0xA0000 >> PAGE_SHIFT;
85 for (i = 0 ; i < 32 ; i++) {
86 if (pte_present(*pg_table))
87 *pg_table = pte_wrprotect(*pg_table);
88 pg_table++;
89 }
90 }
91 }
92
93 asmlinkage int sys_vm86(struct vm86_struct * v86)
94 {
95 struct vm86_struct info;
96 struct pt_regs * pt_regs = (struct pt_regs *) &v86;
97 int error;
98
99 if (current->saved_kernel_stack)
100 return -EPERM;
101
102 error = verify_area(VERIFY_WRITE,v86,sizeof(*v86));
103 if (error)
104 return error;
105 memcpy_fromfs(&info,v86,sizeof(info));
106
107
108
109 info.regs.__null_ds = 0;
110 info.regs.__null_es = 0;
111 info.regs.__null_fs = 0;
112 info.regs.__null_gs = 0;
113
114
115
116
117
118 VEFLAGS = info.regs.eflags;
119 info.regs.eflags &= SAFE_MASK;
120 info.regs.eflags |= pt_regs->eflags & ~SAFE_MASK;
121 info.regs.eflags |= VM_MASK;
122
123 switch (info.cpu_type) {
124 case CPU_286:
125 current->tss.v86mask = 0;
126 break;
127 case CPU_386:
128 current->tss.v86mask = NT_MASK | IOPL_MASK;
129 break;
130 case CPU_486:
131 current->tss.v86mask = AC_MASK | NT_MASK | IOPL_MASK;
132 break;
133 default:
134 current->tss.v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK;
135 break;
136 }
137
138
139
140
141 pt_regs->eax = 0;
142 current->saved_kernel_stack = current->tss.esp0;
143 current->tss.esp0 = (unsigned long) pt_regs;
144 current->tss.vm86_info = v86;
145
146 current->tss.screen_bitmap = info.screen_bitmap;
147 if (info.flags & VM86_SCREEN_BITMAP)
148 mark_screen_rdonly(current);
149 __asm__ __volatile__("movl %0,%%esp\n\t"
150 "jmp ret_from_sys_call"
151 :
152 :"r" (&info.regs));
153 return 0;
154 }
155
156 static inline void return_to_32bit(struct vm86_regs * regs16, int retval)
157 {
158 struct pt_regs * regs32;
159
160 regs32 = save_v86_state(regs16);
161 regs32->eax = retval;
162 __asm__ __volatile__("movl %0,%%esp\n\t"
163 "jmp ret_from_sys_call"
164 : : "r" (regs32));
165 }
166
167 static inline void set_IF(struct vm86_regs * regs)
168 {
169 VEFLAGS |= VIF_MASK;
170 if (VEFLAGS & VIP_MASK)
171 return_to_32bit(regs, VM86_STI);
172 }
173
174 static inline void clear_IF(struct vm86_regs * regs)
175 {
176 VEFLAGS &= ~VIF_MASK;
177 }
178
179 static inline void clear_TF(struct vm86_regs * regs)
180 {
181 regs->eflags &= ~TF_MASK;
182 }
183
184 static inline void set_vflags_long(unsigned long eflags, struct vm86_regs * regs)
185 {
186 set_flags(VEFLAGS, eflags, current->tss.v86mask);
187 set_flags(regs->eflags, eflags, SAFE_MASK);
188 if (eflags & IF_MASK)
189 set_IF(regs);
190 }
191
192 static inline void set_vflags_short(unsigned short flags, struct vm86_regs * regs)
193 {
194 set_flags(VFLAGS, flags, current->tss.v86mask);
195 set_flags(regs->eflags, flags, SAFE_MASK);
196 if (flags & IF_MASK)
197 set_IF(regs);
198 }
199
200 static inline unsigned long get_vflags(struct vm86_regs * regs)
201 {
202 unsigned long flags = regs->eflags & RETURN_MASK;
203
204 if (VEFLAGS & VIF_MASK)
205 flags |= IF_MASK;
206 return flags | (VEFLAGS & current->tss.v86mask);
207 }
208
209 static inline int is_revectored(int nr, struct revectored_struct * bitmap)
210 {
211 __asm__ __volatile__("btl %2,%%fs:%1\n\tsbbl %0,%0"
212 :"=r" (nr)
213 :"m" (*bitmap),"r" (nr));
214 return nr;
215 }
216
217
218
219
220
221
222 #define pushb(base, ptr, val) \
223 __asm__ __volatile__( \
224 "decw %w0\n\t" \
225 "movb %2,%%fs:0(%1,%0)" \
226 : "=r" (ptr) \
227 : "r" (base), "q" (val), "0" (ptr))
228
229 #define pushw(base, ptr, val) \
230 __asm__ __volatile__( \
231 "decw %w0\n\t" \
232 "movb %h2,%%fs:0(%1,%0)\n\t" \
233 "decw %w0\n\t" \
234 "movb %b2,%%fs:0(%1,%0)" \
235 : "=r" (ptr) \
236 : "r" (base), "q" (val), "0" (ptr))
237
238 #define pushl(base, ptr, val) \
239 __asm__ __volatile__( \
240 "decw %w0\n\t" \
241 "rorl $16,%2\n\t" \
242 "movb %h2,%%fs:0(%1,%0)\n\t" \
243 "decw %w0\n\t" \
244 "movb %b2,%%fs:0(%1,%0)\n\t" \
245 "decw %w0\n\t" \
246 "rorl $16,%2\n\t" \
247 "movb %h2,%%fs:0(%1,%0)\n\t" \
248 "decw %w0\n\t" \
249 "movb %b2,%%fs:0(%1,%0)" \
250 : "=r" (ptr) \
251 : "r" (base), "q" (val), "0" (ptr))
252
253 #define popb(base, ptr) \
254 ({ unsigned long __res; \
255 __asm__ __volatile__( \
256 "movb %%fs:0(%1,%0),%b2\n\t" \
257 "incw %w0" \
258 : "=r" (ptr), "=r" (base), "=q" (__res) \
259 : "0" (ptr), "1" (base), "2" (0)); \
260 __res; })
261
262 #define popw(base, ptr) \
263 ({ unsigned long __res; \
264 __asm__ __volatile__( \
265 "movb %%fs:0(%1,%0),%b2\n\t" \
266 "incw %w0\n\t" \
267 "movb %%fs:0(%1,%0),%h2\n\t" \
268 "incw %w0" \
269 : "=r" (ptr), "=r" (base), "=q" (__res) \
270 : "0" (ptr), "1" (base), "2" (0)); \
271 __res; })
272
273 #define popl(base, ptr) \
274 ({ unsigned long __res; \
275 __asm__ __volatile__( \
276 "movb %%fs:0(%1,%0),%b2\n\t" \
277 "incw %w0\n\t" \
278 "movb %%fs:0(%1,%0),%h2\n\t" \
279 "incw %w0\n\t" \
280 "rorl $16,%2\n\t" \
281 "movb %%fs:0(%1,%0),%b2\n\t" \
282 "incw %w0\n\t" \
283 "movb %%fs:0(%1,%0),%h2\n\t" \
284 "incw %w0\n\t" \
285 "rorl $16,%2" \
286 : "=r" (ptr), "=r" (base), "=q" (__res) \
287 : "0" (ptr), "1" (base)); \
288 __res; })
289
290 static void do_int(struct vm86_regs *regs, int i, unsigned char * ssp, unsigned long sp)
291 {
292 unsigned short seg = get_fs_word((void *) ((i<<2)+2));
293
294 if (seg == BIOSSEG || regs->cs == BIOSSEG ||
295 is_revectored(i, ¤t->tss.vm86_info->int_revectored))
296 return_to_32bit(regs, VM86_INTx + (i << 8));
297 if (i==0x21 && is_revectored(AH(regs),¤t->tss.vm86_info->int21_revectored))
298 return_to_32bit(regs, VM86_INTx + (i << 8));
299 pushw(ssp, sp, get_vflags(regs));
300 pushw(ssp, sp, regs->cs);
301 pushw(ssp, sp, IP(regs));
302 regs->cs = seg;
303 SP(regs) -= 6;
304 IP(regs) = get_fs_word((void *) (i<<2));
305 clear_TF(regs);
306 clear_IF(regs);
307 return;
308 }
309
310 void handle_vm86_debug(struct vm86_regs * regs, long error_code)
311 {
312 #if 0
313 do_int(regs, 1, (unsigned char *) (regs->ss << 4), SP(regs));
314 #else
315 if (current->flags & PF_PTRACED)
316 current->blocked &= ~(1 << (SIGTRAP-1));
317 send_sig(SIGTRAP, current, 1);
318 current->tss.trap_no = 1;
319 current->tss.error_code = error_code;
320 #endif
321 }
322
323 void handle_vm86_fault(struct vm86_regs * regs, long error_code)
324 {
325 unsigned char *csp, *ssp;
326 unsigned long ip, sp;
327
328 csp = (unsigned char *) (regs->cs << 4);
329 ssp = (unsigned char *) (regs->ss << 4);
330 sp = SP(regs);
331 ip = IP(regs);
332
333 switch (popb(csp, ip)) {
334
335
336 case 0x66:
337 switch (popb(csp, ip)) {
338
339
340 case 0x9c:
341 SP(regs) -= 4;
342 IP(regs) += 2;
343 pushl(ssp, sp, get_vflags(regs));
344 return;
345
346
347 case 0x9d:
348 SP(regs) += 4;
349 IP(regs) += 2;
350 set_vflags_long(popl(ssp, sp), regs);
351 return;
352 }
353
354
355 case 0x9c:
356 SP(regs) -= 2;
357 IP(regs)++;
358 pushw(ssp, sp, get_vflags(regs));
359 return;
360
361
362 case 0x9d:
363 SP(regs) += 2;
364 IP(regs)++;
365 set_vflags_short(popw(ssp, sp), regs);
366 return;
367
368
369 case 0xcc:
370 IP(regs)++;
371 do_int(regs, 3, ssp, sp);
372 return;
373
374
375 case 0xcd:
376 IP(regs) += 2;
377 do_int(regs, popb(csp, ip), ssp, sp);
378 return;
379
380
381 case 0xcf:
382 SP(regs) += 6;
383 IP(regs) = popw(ssp, sp);
384 regs->cs = popw(ssp, sp);
385 set_vflags_short(popw(ssp, sp), regs);
386 return;
387
388
389 case 0xfa:
390 IP(regs)++;
391 clear_IF(regs);
392 return;
393
394
395
396
397
398
399
400
401 case 0xfb:
402 IP(regs)++;
403 set_IF(regs);
404 return;
405
406 default:
407 return_to_32bit(regs, VM86_UNKNOWN);
408 }
409 }