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/pgtable.h>
16 #include <asm/io.h>
17
18
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20
21
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25
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34
35
36 #define AL(regs) (((unsigned char *)&((regs)->eax))[0])
37 #define AH(regs) (((unsigned char *)&((regs)->eax))[1])
38 #define IP(regs) (*(unsigned short *)&((regs)->eip))
39 #define SP(regs) (*(unsigned short *)&((regs)->esp))
40
41
42
43
44 #define VFLAGS (*(unsigned short *)&(current->tss.v86flags))
45 #define VEFLAGS (current->tss.v86flags)
46
47 #define set_flags(X,new,mask) \
48 ((X) = ((X) & ~(mask)) | ((new) & (mask)))
49
50 #define SAFE_MASK (0xDD5)
51 #define RETURN_MASK (0xDFF)
52
53 asmlinkage struct pt_regs * save_v86_state(struct vm86_regs * regs)
54 {
55 unsigned long tmp;
56
57 if (!current->tss.vm86_info) {
58 printk("no vm86_info: BAD\n");
59 do_exit(SIGSEGV);
60 }
61 set_flags(regs->eflags, VEFLAGS, VIF_MASK | current->tss.v86mask);
62 memcpy_tofs(¤t->tss.vm86_info->regs,regs,sizeof(*regs));
63 put_fs_long(current->tss.screen_bitmap,¤t->tss.vm86_info->screen_bitmap);
64 tmp = current->tss.esp0;
65 current->tss.esp0 = current->saved_kernel_stack;
66 current->saved_kernel_stack = 0;
67 return (struct pt_regs *) tmp;
68 }
69
70 static void mark_screen_rdonly(struct task_struct * tsk)
71 {
72 pgd_t *pg_dir;
73
74 pg_dir = PAGE_DIR_OFFSET(tsk, 0);
75 if (!pgd_none(*pg_dir)) {
76 pte_t *pg_table;
77 int i;
78
79 if (pgd_bad(*pg_dir)) {
80 printk("vm86: bad page table directory entry %08lx\n", pgd_val(*pg_dir));
81 pgd_clear(pg_dir);
82 return;
83 }
84 pg_table = (pte_t *) pgd_page(*pg_dir);
85 pg_table += 0xA0000 >> PAGE_SHIFT;
86 for (i = 0 ; i < 32 ; i++) {
87 if (pte_present(*pg_table))
88 *pg_table = pte_wrprotect(*pg_table);
89 pg_table++;
90 }
91 }
92 }
93
94 asmlinkage int sys_vm86(struct vm86_struct * v86)
95 {
96 struct vm86_struct info;
97 struct pt_regs * pt_regs = (struct pt_regs *) &v86;
98 int error;
99
100 if (current->saved_kernel_stack)
101 return -EPERM;
102
103 error = verify_area(VERIFY_WRITE,v86,sizeof(*v86));
104 if (error)
105 return error;
106 memcpy_fromfs(&info,v86,sizeof(info));
107
108
109
110 info.regs.__null_ds = 0;
111 info.regs.__null_es = 0;
112 info.regs.__null_fs = 0;
113 info.regs.__null_gs = 0;
114
115
116
117
118
119 VEFLAGS = info.regs.eflags;
120 info.regs.eflags &= SAFE_MASK;
121 info.regs.eflags |= pt_regs->eflags & ~SAFE_MASK;
122 info.regs.eflags |= VM_MASK;
123
124 switch (info.cpu_type) {
125 case CPU_286:
126 current->tss.v86mask = 0;
127 break;
128 case CPU_386:
129 current->tss.v86mask = NT_MASK | IOPL_MASK;
130 break;
131 case CPU_486:
132 current->tss.v86mask = AC_MASK | NT_MASK | IOPL_MASK;
133 break;
134 default:
135 current->tss.v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK;
136 break;
137 }
138
139
140
141
142 pt_regs->eax = 0;
143 current->saved_kernel_stack = current->tss.esp0;
144 current->tss.esp0 = (unsigned long) pt_regs;
145 current->tss.vm86_info = v86;
146
147 current->tss.screen_bitmap = info.screen_bitmap;
148 if (info.flags & VM86_SCREEN_BITMAP)
149 mark_screen_rdonly(current);
150 __asm__ __volatile__("movl %0,%%esp\n\t"
151 "jmp ret_from_sys_call"
152 :
153 :"r" (&info.regs));
154 return 0;
155 }
156
157 static inline void return_to_32bit(struct vm86_regs * regs16, int retval)
158 {
159 struct pt_regs * regs32;
160
161 regs32 = save_v86_state(regs16);
162 regs32->eax = retval;
163 __asm__ __volatile__("movl %0,%%esp\n\t"
164 "jmp ret_from_sys_call"
165 : : "r" (regs32));
166 }
167
168 static inline void set_IF(struct vm86_regs * regs)
169 {
170 VEFLAGS |= VIF_MASK;
171 if (VEFLAGS & VIP_MASK)
172 return_to_32bit(regs, VM86_STI);
173 }
174
175 static inline void clear_IF(struct vm86_regs * regs)
176 {
177 VEFLAGS &= ~VIF_MASK;
178 }
179
180 static inline void clear_TF(struct vm86_regs * regs)
181 {
182 regs->eflags &= ~TF_MASK;
183 }
184
185 static inline void set_vflags_long(unsigned long eflags, struct vm86_regs * regs)
186 {
187 set_flags(VEFLAGS, eflags, current->tss.v86mask);
188 set_flags(regs->eflags, eflags, SAFE_MASK);
189 if (eflags & IF_MASK)
190 set_IF(regs);
191 }
192
193 static inline void set_vflags_short(unsigned short flags, struct vm86_regs * regs)
194 {
195 set_flags(VFLAGS, flags, current->tss.v86mask);
196 set_flags(regs->eflags, flags, SAFE_MASK);
197 if (flags & IF_MASK)
198 set_IF(regs);
199 }
200
201 static inline unsigned long get_vflags(struct vm86_regs * regs)
202 {
203 unsigned long flags = regs->eflags & RETURN_MASK;
204
205 if (VEFLAGS & VIF_MASK)
206 flags |= IF_MASK;
207 return flags | (VEFLAGS & current->tss.v86mask);
208 }
209
210 static inline int is_revectored(int nr, struct revectored_struct * bitmap)
211 {
212 __asm__ __volatile__("btl %2,%%fs:%1\n\tsbbl %0,%0"
213 :"=r" (nr)
214 :"m" (*bitmap),"r" (nr));
215 return nr;
216 }
217
218
219
220
221
222
223 #define pushb(base, ptr, val) \
224 __asm__ __volatile__( \
225 "decw %w0\n\t" \
226 "movb %2,%%fs:0(%1,%0)" \
227 : "=r" (ptr) \
228 : "r" (base), "q" (val), "0" (ptr))
229
230 #define pushw(base, ptr, val) \
231 __asm__ __volatile__( \
232 "decw %w0\n\t" \
233 "movb %h2,%%fs:0(%1,%0)\n\t" \
234 "decw %w0\n\t" \
235 "movb %b2,%%fs:0(%1,%0)" \
236 : "=r" (ptr) \
237 : "r" (base), "q" (val), "0" (ptr))
238
239 #define pushl(base, ptr, val) \
240 __asm__ __volatile__( \
241 "decw %w0\n\t" \
242 "rorl $16,%2\n\t" \
243 "movb %h2,%%fs:0(%1,%0)\n\t" \
244 "decw %w0\n\t" \
245 "movb %b2,%%fs:0(%1,%0)\n\t" \
246 "decw %w0\n\t" \
247 "rorl $16,%2\n\t" \
248 "movb %h2,%%fs:0(%1,%0)\n\t" \
249 "decw %w0\n\t" \
250 "movb %b2,%%fs:0(%1,%0)" \
251 : "=r" (ptr) \
252 : "r" (base), "q" (val), "0" (ptr))
253
254 #define popb(base, ptr) \
255 ({ unsigned long __res; \
256 __asm__ __volatile__( \
257 "movb %%fs:0(%1,%0),%b2\n\t" \
258 "incw %w0" \
259 : "=r" (ptr), "=r" (base), "=q" (__res) \
260 : "0" (ptr), "1" (base), "2" (0)); \
261 __res; })
262
263 #define popw(base, ptr) \
264 ({ unsigned long __res; \
265 __asm__ __volatile__( \
266 "movb %%fs:0(%1,%0),%b2\n\t" \
267 "incw %w0\n\t" \
268 "movb %%fs:0(%1,%0),%h2\n\t" \
269 "incw %w0" \
270 : "=r" (ptr), "=r" (base), "=q" (__res) \
271 : "0" (ptr), "1" (base), "2" (0)); \
272 __res; })
273
274 #define popl(base, ptr) \
275 ({ unsigned long __res; \
276 __asm__ __volatile__( \
277 "movb %%fs:0(%1,%0),%b2\n\t" \
278 "incw %w0\n\t" \
279 "movb %%fs:0(%1,%0),%h2\n\t" \
280 "incw %w0\n\t" \
281 "rorl $16,%2\n\t" \
282 "movb %%fs:0(%1,%0),%b2\n\t" \
283 "incw %w0\n\t" \
284 "movb %%fs:0(%1,%0),%h2\n\t" \
285 "incw %w0\n\t" \
286 "rorl $16,%2" \
287 : "=r" (ptr), "=r" (base), "=q" (__res) \
288 : "0" (ptr), "1" (base)); \
289 __res; })
290
291 static void do_int(struct vm86_regs *regs, int i, unsigned char * ssp, unsigned long sp)
292 {
293 unsigned short seg = get_fs_word((void *) ((i<<2)+2));
294
295 if (seg == BIOSSEG || regs->cs == BIOSSEG ||
296 is_revectored(i, ¤t->tss.vm86_info->int_revectored))
297 return_to_32bit(regs, VM86_INTx + (i << 8));
298 if (i==0x21 && is_revectored(AH(regs),¤t->tss.vm86_info->int21_revectored))
299 return_to_32bit(regs, VM86_INTx + (i << 8));
300 pushw(ssp, sp, get_vflags(regs));
301 pushw(ssp, sp, regs->cs);
302 pushw(ssp, sp, IP(regs));
303 regs->cs = seg;
304 SP(regs) -= 6;
305 IP(regs) = get_fs_word((void *) (i<<2));
306 clear_TF(regs);
307 clear_IF(regs);
308 return;
309 }
310
311 void handle_vm86_debug(struct vm86_regs * regs, long error_code)
312 {
313 #if 0
314 do_int(regs, 1, (unsigned char *) (regs->ss << 4), SP(regs));
315 #else
316 if (current->flags & PF_PTRACED)
317 current->blocked &= ~(1 << (SIGTRAP-1));
318 send_sig(SIGTRAP, current, 1);
319 current->tss.trap_no = 1;
320 current->tss.error_code = error_code;
321 #endif
322 }
323
324 void handle_vm86_fault(struct vm86_regs * regs, long error_code)
325 {
326 unsigned char *csp, *ssp;
327 unsigned long ip, sp;
328
329 csp = (unsigned char *) (regs->cs << 4);
330 ssp = (unsigned char *) (regs->ss << 4);
331 sp = SP(regs);
332 ip = IP(regs);
333
334 switch (popb(csp, ip)) {
335
336
337 case 0x66:
338 switch (popb(csp, ip)) {
339
340
341 case 0x9c:
342 SP(regs) -= 4;
343 IP(regs) += 2;
344 pushl(ssp, sp, get_vflags(regs));
345 return;
346
347
348 case 0x9d:
349 SP(regs) += 4;
350 IP(regs) += 2;
351 set_vflags_long(popl(ssp, sp), regs);
352 return;
353 }
354
355
356 case 0x9c:
357 SP(regs) -= 2;
358 IP(regs)++;
359 pushw(ssp, sp, get_vflags(regs));
360 return;
361
362
363 case 0x9d:
364 SP(regs) += 2;
365 IP(regs)++;
366 set_vflags_short(popw(ssp, sp), regs);
367 return;
368
369
370 case 0xcd:
371 IP(regs) += 2;
372 do_int(regs, popb(csp, ip), ssp, sp);
373 return;
374
375
376 case 0xcf:
377 SP(regs) += 6;
378 IP(regs) = popw(ssp, sp);
379 regs->cs = popw(ssp, sp);
380 set_vflags_short(popw(ssp, sp), regs);
381 return;
382
383
384 case 0xfa:
385 IP(regs)++;
386 clear_IF(regs);
387 return;
388
389
390
391
392
393
394
395
396 case 0xfb:
397 IP(regs)++;
398 set_IF(regs);
399 return;
400
401 default:
402 return_to_32bit(regs, VM86_UNKNOWN);
403 }
404 }