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1da177e4 LT |
1 | /* |
2 | * linux/kernel/vm86.c | |
3 | * | |
4 | * Copyright (C) 1994 Linus Torvalds | |
5 | * | |
6 | * 29 dec 2001 - Fixed oopses caused by unchecked access to the vm86 | |
624dffcb | 7 | * stack - Manfred Spraul <manfred@colorfullife.com> |
1da177e4 LT |
8 | * |
9 | * 22 mar 2002 - Manfred detected the stackfaults, but didn't handle | |
10 | * them correctly. Now the emulation will be in a | |
11 | * consistent state after stackfaults - Kasper Dupont | |
12 | * <kasperd@daimi.au.dk> | |
13 | * | |
14 | * 22 mar 2002 - Added missing clear_IF in set_vflags_* Kasper Dupont | |
15 | * <kasperd@daimi.au.dk> | |
16 | * | |
17 | * ?? ??? 2002 - Fixed premature returns from handle_vm86_fault | |
18 | * caused by Kasper Dupont's changes - Stas Sergeev | |
19 | * | |
20 | * 4 apr 2002 - Fixed CHECK_IF_IN_TRAP broken by Stas' changes. | |
21 | * Kasper Dupont <kasperd@daimi.au.dk> | |
22 | * | |
23 | * 9 apr 2002 - Changed syntax of macros in handle_vm86_fault. | |
24 | * Kasper Dupont <kasperd@daimi.au.dk> | |
25 | * | |
26 | * 9 apr 2002 - Changed stack access macros to jump to a label | |
27 | * instead of returning to userspace. This simplifies | |
28 | * do_int, and is needed by handle_vm6_fault. Kasper | |
29 | * Dupont <kasperd@daimi.au.dk> | |
30 | * | |
31 | */ | |
32 | ||
a9415644 | 33 | #include <linux/capability.h> |
1da177e4 LT |
34 | #include <linux/config.h> |
35 | #include <linux/errno.h> | |
36 | #include <linux/interrupt.h> | |
37 | #include <linux/sched.h> | |
38 | #include <linux/kernel.h> | |
39 | #include <linux/signal.h> | |
40 | #include <linux/string.h> | |
41 | #include <linux/mm.h> | |
42 | #include <linux/smp.h> | |
43 | #include <linux/smp_lock.h> | |
44 | #include <linux/highmem.h> | |
45 | #include <linux/ptrace.h> | |
46 | ||
47 | #include <asm/uaccess.h> | |
48 | #include <asm/io.h> | |
49 | #include <asm/tlbflush.h> | |
50 | #include <asm/irq.h> | |
51 | ||
52 | /* | |
53 | * Known problems: | |
54 | * | |
55 | * Interrupt handling is not guaranteed: | |
56 | * - a real x86 will disable all interrupts for one instruction | |
57 | * after a "mov ss,xx" to make stack handling atomic even without | |
58 | * the 'lss' instruction. We can't guarantee this in v86 mode, | |
59 | * as the next instruction might result in a page fault or similar. | |
60 | * - a real x86 will have interrupts disabled for one instruction | |
61 | * past the 'sti' that enables them. We don't bother with all the | |
62 | * details yet. | |
63 | * | |
64 | * Let's hope these problems do not actually matter for anything. | |
65 | */ | |
66 | ||
67 | ||
68 | #define KVM86 ((struct kernel_vm86_struct *)regs) | |
69 | #define VMPI KVM86->vm86plus | |
70 | ||
71 | ||
72 | /* | |
73 | * 8- and 16-bit register defines.. | |
74 | */ | |
75 | #define AL(regs) (((unsigned char *)&((regs)->eax))[0]) | |
76 | #define AH(regs) (((unsigned char *)&((regs)->eax))[1]) | |
77 | #define IP(regs) (*(unsigned short *)&((regs)->eip)) | |
78 | #define SP(regs) (*(unsigned short *)&((regs)->esp)) | |
79 | ||
80 | /* | |
81 | * virtual flags (16 and 32-bit versions) | |
82 | */ | |
83 | #define VFLAGS (*(unsigned short *)&(current->thread.v86flags)) | |
84 | #define VEFLAGS (current->thread.v86flags) | |
85 | ||
86 | #define set_flags(X,new,mask) \ | |
87 | ((X) = ((X) & ~(mask)) | ((new) & (mask))) | |
88 | ||
89 | #define SAFE_MASK (0xDD5) | |
90 | #define RETURN_MASK (0xDFF) | |
91 | ||
92 | #define VM86_REGS_PART2 orig_eax | |
93 | #define VM86_REGS_SIZE1 \ | |
94 | ( (unsigned)( & (((struct kernel_vm86_regs *)0)->VM86_REGS_PART2) ) ) | |
95 | #define VM86_REGS_SIZE2 (sizeof(struct kernel_vm86_regs) - VM86_REGS_SIZE1) | |
96 | ||
97 | struct pt_regs * FASTCALL(save_v86_state(struct kernel_vm86_regs * regs)); | |
98 | struct pt_regs * fastcall save_v86_state(struct kernel_vm86_regs * regs) | |
99 | { | |
100 | struct tss_struct *tss; | |
101 | struct pt_regs *ret; | |
102 | unsigned long tmp; | |
103 | ||
104 | /* | |
105 | * This gets called from entry.S with interrupts disabled, but | |
106 | * from process context. Enable interrupts here, before trying | |
107 | * to access user space. | |
108 | */ | |
109 | local_irq_enable(); | |
110 | ||
111 | if (!current->thread.vm86_info) { | |
112 | printk("no vm86_info: BAD\n"); | |
113 | do_exit(SIGSEGV); | |
114 | } | |
115 | set_flags(regs->eflags, VEFLAGS, VIF_MASK | current->thread.v86mask); | |
116 | tmp = copy_to_user(¤t->thread.vm86_info->regs,regs, VM86_REGS_SIZE1); | |
117 | tmp += copy_to_user(¤t->thread.vm86_info->regs.VM86_REGS_PART2, | |
118 | ®s->VM86_REGS_PART2, VM86_REGS_SIZE2); | |
119 | tmp += put_user(current->thread.screen_bitmap,¤t->thread.vm86_info->screen_bitmap); | |
120 | if (tmp) { | |
121 | printk("vm86: could not access userspace vm86_info\n"); | |
122 | do_exit(SIGSEGV); | |
123 | } | |
124 | ||
125 | tss = &per_cpu(init_tss, get_cpu()); | |
126 | current->thread.esp0 = current->thread.saved_esp0; | |
127 | current->thread.sysenter_cs = __KERNEL_CS; | |
128 | load_esp0(tss, ¤t->thread); | |
129 | current->thread.saved_esp0 = 0; | |
130 | put_cpu(); | |
131 | ||
132 | loadsegment(fs, current->thread.saved_fs); | |
133 | loadsegment(gs, current->thread.saved_gs); | |
134 | ret = KVM86->regs32; | |
135 | return ret; | |
136 | } | |
137 | ||
60ec5585 | 138 | static void mark_screen_rdonly(struct mm_struct *mm) |
1da177e4 LT |
139 | { |
140 | pgd_t *pgd; | |
141 | pud_t *pud; | |
142 | pmd_t *pmd; | |
60ec5585 HD |
143 | pte_t *pte; |
144 | spinlock_t *ptl; | |
1da177e4 LT |
145 | int i; |
146 | ||
60ec5585 | 147 | pgd = pgd_offset(mm, 0xA0000); |
1da177e4 LT |
148 | if (pgd_none_or_clear_bad(pgd)) |
149 | goto out; | |
150 | pud = pud_offset(pgd, 0xA0000); | |
151 | if (pud_none_or_clear_bad(pud)) | |
152 | goto out; | |
153 | pmd = pmd_offset(pud, 0xA0000); | |
154 | if (pmd_none_or_clear_bad(pmd)) | |
155 | goto out; | |
60ec5585 | 156 | pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); |
1da177e4 LT |
157 | for (i = 0; i < 32; i++) { |
158 | if (pte_present(*pte)) | |
159 | set_pte(pte, pte_wrprotect(*pte)); | |
160 | pte++; | |
161 | } | |
60ec5585 | 162 | pte_unmap_unlock(pte, ptl); |
1da177e4 | 163 | out: |
1da177e4 LT |
164 | flush_tlb(); |
165 | } | |
166 | ||
167 | ||
168 | ||
169 | static int do_vm86_irq_handling(int subfunction, int irqnumber); | |
170 | static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk); | |
171 | ||
172 | asmlinkage int sys_vm86old(struct pt_regs regs) | |
173 | { | |
174 | struct vm86_struct __user *v86 = (struct vm86_struct __user *)regs.ebx; | |
175 | struct kernel_vm86_struct info; /* declare this _on top_, | |
176 | * this avoids wasting of stack space. | |
177 | * This remains on the stack until we | |
178 | * return to 32 bit user space. | |
179 | */ | |
180 | struct task_struct *tsk; | |
181 | int tmp, ret = -EPERM; | |
182 | ||
183 | tsk = current; | |
184 | if (tsk->thread.saved_esp0) | |
185 | goto out; | |
186 | tmp = copy_from_user(&info, v86, VM86_REGS_SIZE1); | |
187 | tmp += copy_from_user(&info.regs.VM86_REGS_PART2, &v86->regs.VM86_REGS_PART2, | |
188 | (long)&info.vm86plus - (long)&info.regs.VM86_REGS_PART2); | |
189 | ret = -EFAULT; | |
190 | if (tmp) | |
191 | goto out; | |
192 | memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus); | |
193 | info.regs32 = ®s; | |
194 | tsk->thread.vm86_info = v86; | |
195 | do_sys_vm86(&info, tsk); | |
196 | ret = 0; /* we never return here */ | |
197 | out: | |
198 | return ret; | |
199 | } | |
200 | ||
201 | ||
202 | asmlinkage int sys_vm86(struct pt_regs regs) | |
203 | { | |
204 | struct kernel_vm86_struct info; /* declare this _on top_, | |
205 | * this avoids wasting of stack space. | |
206 | * This remains on the stack until we | |
207 | * return to 32 bit user space. | |
208 | */ | |
209 | struct task_struct *tsk; | |
210 | int tmp, ret; | |
211 | struct vm86plus_struct __user *v86; | |
212 | ||
213 | tsk = current; | |
214 | switch (regs.ebx) { | |
215 | case VM86_REQUEST_IRQ: | |
216 | case VM86_FREE_IRQ: | |
217 | case VM86_GET_IRQ_BITS: | |
218 | case VM86_GET_AND_RESET_IRQ: | |
219 | ret = do_vm86_irq_handling(regs.ebx, (int)regs.ecx); | |
220 | goto out; | |
221 | case VM86_PLUS_INSTALL_CHECK: | |
222 | /* NOTE: on old vm86 stuff this will return the error | |
e49332bd | 223 | from access_ok(), because the subfunction is |
1da177e4 LT |
224 | interpreted as (invalid) address to vm86_struct. |
225 | So the installation check works. | |
226 | */ | |
227 | ret = 0; | |
228 | goto out; | |
229 | } | |
230 | ||
231 | /* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */ | |
232 | ret = -EPERM; | |
233 | if (tsk->thread.saved_esp0) | |
234 | goto out; | |
235 | v86 = (struct vm86plus_struct __user *)regs.ecx; | |
236 | tmp = copy_from_user(&info, v86, VM86_REGS_SIZE1); | |
237 | tmp += copy_from_user(&info.regs.VM86_REGS_PART2, &v86->regs.VM86_REGS_PART2, | |
238 | (long)&info.regs32 - (long)&info.regs.VM86_REGS_PART2); | |
239 | ret = -EFAULT; | |
240 | if (tmp) | |
241 | goto out; | |
242 | info.regs32 = ®s; | |
243 | info.vm86plus.is_vm86pus = 1; | |
244 | tsk->thread.vm86_info = (struct vm86_struct __user *)v86; | |
245 | do_sys_vm86(&info, tsk); | |
246 | ret = 0; /* we never return here */ | |
247 | out: | |
248 | return ret; | |
249 | } | |
250 | ||
251 | ||
252 | static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk) | |
253 | { | |
254 | struct tss_struct *tss; | |
255 | /* | |
256 | * make sure the vm86() system call doesn't try to do anything silly | |
257 | */ | |
258 | info->regs.__null_ds = 0; | |
259 | info->regs.__null_es = 0; | |
260 | ||
261 | /* we are clearing fs,gs later just before "jmp resume_userspace", | |
262 | * because starting with Linux 2.1.x they aren't no longer saved/restored | |
263 | */ | |
264 | ||
265 | /* | |
266 | * The eflags register is also special: we cannot trust that the user | |
267 | * has set it up safely, so this makes sure interrupt etc flags are | |
268 | * inherited from protected mode. | |
269 | */ | |
270 | VEFLAGS = info->regs.eflags; | |
271 | info->regs.eflags &= SAFE_MASK; | |
272 | info->regs.eflags |= info->regs32->eflags & ~SAFE_MASK; | |
273 | info->regs.eflags |= VM_MASK; | |
274 | ||
275 | switch (info->cpu_type) { | |
276 | case CPU_286: | |
277 | tsk->thread.v86mask = 0; | |
278 | break; | |
279 | case CPU_386: | |
280 | tsk->thread.v86mask = NT_MASK | IOPL_MASK; | |
281 | break; | |
282 | case CPU_486: | |
283 | tsk->thread.v86mask = AC_MASK | NT_MASK | IOPL_MASK; | |
284 | break; | |
285 | default: | |
286 | tsk->thread.v86mask = ID_MASK | AC_MASK | NT_MASK | IOPL_MASK; | |
287 | break; | |
288 | } | |
289 | ||
290 | /* | |
291 | * Save old state, set default return value (%eax) to 0 | |
292 | */ | |
293 | info->regs32->eax = 0; | |
294 | tsk->thread.saved_esp0 = tsk->thread.esp0; | |
4d37e7e3 ZA |
295 | savesegment(fs, tsk->thread.saved_fs); |
296 | savesegment(gs, tsk->thread.saved_gs); | |
1da177e4 LT |
297 | |
298 | tss = &per_cpu(init_tss, get_cpu()); | |
299 | tsk->thread.esp0 = (unsigned long) &info->VM86_TSS_ESP0; | |
300 | if (cpu_has_sep) | |
301 | tsk->thread.sysenter_cs = 0; | |
302 | load_esp0(tss, &tsk->thread); | |
303 | put_cpu(); | |
304 | ||
305 | tsk->thread.screen_bitmap = info->screen_bitmap; | |
306 | if (info->flags & VM86_SCREEN_BITMAP) | |
60ec5585 | 307 | mark_screen_rdonly(tsk->mm); |
1da177e4 LT |
308 | __asm__ __volatile__( |
309 | "xorl %%eax,%%eax; movl %%eax,%%fs; movl %%eax,%%gs\n\t" | |
310 | "movl %0,%%esp\n\t" | |
311 | "movl %1,%%ebp\n\t" | |
312 | "jmp resume_userspace" | |
313 | : /* no outputs */ | |
06b425d8 | 314 | :"r" (&info->regs), "r" (task_thread_info(tsk)) : "ax"); |
1da177e4 LT |
315 | /* we never return here */ |
316 | } | |
317 | ||
318 | static inline void return_to_32bit(struct kernel_vm86_regs * regs16, int retval) | |
319 | { | |
320 | struct pt_regs * regs32; | |
321 | ||
322 | regs32 = save_v86_state(regs16); | |
323 | regs32->eax = retval; | |
324 | __asm__ __volatile__("movl %0,%%esp\n\t" | |
325 | "movl %1,%%ebp\n\t" | |
326 | "jmp resume_userspace" | |
327 | : : "r" (regs32), "r" (current_thread_info())); | |
328 | } | |
329 | ||
330 | static inline void set_IF(struct kernel_vm86_regs * regs) | |
331 | { | |
332 | VEFLAGS |= VIF_MASK; | |
333 | if (VEFLAGS & VIP_MASK) | |
334 | return_to_32bit(regs, VM86_STI); | |
335 | } | |
336 | ||
337 | static inline void clear_IF(struct kernel_vm86_regs * regs) | |
338 | { | |
339 | VEFLAGS &= ~VIF_MASK; | |
340 | } | |
341 | ||
342 | static inline void clear_TF(struct kernel_vm86_regs * regs) | |
343 | { | |
344 | regs->eflags &= ~TF_MASK; | |
345 | } | |
346 | ||
347 | static inline void clear_AC(struct kernel_vm86_regs * regs) | |
348 | { | |
349 | regs->eflags &= ~AC_MASK; | |
350 | } | |
351 | ||
352 | /* It is correct to call set_IF(regs) from the set_vflags_* | |
353 | * functions. However someone forgot to call clear_IF(regs) | |
354 | * in the opposite case. | |
355 | * After the command sequence CLI PUSHF STI POPF you should | |
356 | * end up with interrups disabled, but you ended up with | |
357 | * interrupts enabled. | |
358 | * ( I was testing my own changes, but the only bug I | |
359 | * could find was in a function I had not changed. ) | |
360 | * [KD] | |
361 | */ | |
362 | ||
363 | static inline void set_vflags_long(unsigned long eflags, struct kernel_vm86_regs * regs) | |
364 | { | |
365 | set_flags(VEFLAGS, eflags, current->thread.v86mask); | |
366 | set_flags(regs->eflags, eflags, SAFE_MASK); | |
367 | if (eflags & IF_MASK) | |
368 | set_IF(regs); | |
369 | else | |
370 | clear_IF(regs); | |
371 | } | |
372 | ||
373 | static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs * regs) | |
374 | { | |
375 | set_flags(VFLAGS, flags, current->thread.v86mask); | |
376 | set_flags(regs->eflags, flags, SAFE_MASK); | |
377 | if (flags & IF_MASK) | |
378 | set_IF(regs); | |
379 | else | |
380 | clear_IF(regs); | |
381 | } | |
382 | ||
383 | static inline unsigned long get_vflags(struct kernel_vm86_regs * regs) | |
384 | { | |
385 | unsigned long flags = regs->eflags & RETURN_MASK; | |
386 | ||
387 | if (VEFLAGS & VIF_MASK) | |
388 | flags |= IF_MASK; | |
389 | flags |= IOPL_MASK; | |
390 | return flags | (VEFLAGS & current->thread.v86mask); | |
391 | } | |
392 | ||
393 | static inline int is_revectored(int nr, struct revectored_struct * bitmap) | |
394 | { | |
395 | __asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0" | |
396 | :"=r" (nr) | |
397 | :"m" (*bitmap),"r" (nr)); | |
398 | return nr; | |
399 | } | |
400 | ||
401 | #define val_byte(val, n) (((__u8 *)&val)[n]) | |
402 | ||
403 | #define pushb(base, ptr, val, err_label) \ | |
404 | do { \ | |
405 | __u8 __val = val; \ | |
406 | ptr--; \ | |
407 | if (put_user(__val, base + ptr) < 0) \ | |
408 | goto err_label; \ | |
409 | } while(0) | |
410 | ||
411 | #define pushw(base, ptr, val, err_label) \ | |
412 | do { \ | |
413 | __u16 __val = val; \ | |
414 | ptr--; \ | |
415 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
416 | goto err_label; \ | |
417 | ptr--; \ | |
418 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
419 | goto err_label; \ | |
420 | } while(0) | |
421 | ||
422 | #define pushl(base, ptr, val, err_label) \ | |
423 | do { \ | |
424 | __u32 __val = val; \ | |
425 | ptr--; \ | |
426 | if (put_user(val_byte(__val, 3), base + ptr) < 0) \ | |
427 | goto err_label; \ | |
428 | ptr--; \ | |
429 | if (put_user(val_byte(__val, 2), base + ptr) < 0) \ | |
430 | goto err_label; \ | |
431 | ptr--; \ | |
432 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
433 | goto err_label; \ | |
434 | ptr--; \ | |
435 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
436 | goto err_label; \ | |
437 | } while(0) | |
438 | ||
439 | #define popb(base, ptr, err_label) \ | |
440 | ({ \ | |
441 | __u8 __res; \ | |
442 | if (get_user(__res, base + ptr) < 0) \ | |
443 | goto err_label; \ | |
444 | ptr++; \ | |
445 | __res; \ | |
446 | }) | |
447 | ||
448 | #define popw(base, ptr, err_label) \ | |
449 | ({ \ | |
450 | __u16 __res; \ | |
451 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
452 | goto err_label; \ | |
453 | ptr++; \ | |
454 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
455 | goto err_label; \ | |
456 | ptr++; \ | |
457 | __res; \ | |
458 | }) | |
459 | ||
460 | #define popl(base, ptr, err_label) \ | |
461 | ({ \ | |
462 | __u32 __res; \ | |
463 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
464 | goto err_label; \ | |
465 | ptr++; \ | |
466 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
467 | goto err_label; \ | |
468 | ptr++; \ | |
469 | if (get_user(val_byte(__res, 2), base + ptr) < 0) \ | |
470 | goto err_label; \ | |
471 | ptr++; \ | |
472 | if (get_user(val_byte(__res, 3), base + ptr) < 0) \ | |
473 | goto err_label; \ | |
474 | ptr++; \ | |
475 | __res; \ | |
476 | }) | |
477 | ||
478 | /* There are so many possible reasons for this function to return | |
479 | * VM86_INTx, so adding another doesn't bother me. We can expect | |
480 | * userspace programs to be able to handle it. (Getting a problem | |
481 | * in userspace is always better than an Oops anyway.) [KD] | |
482 | */ | |
483 | static void do_int(struct kernel_vm86_regs *regs, int i, | |
484 | unsigned char __user * ssp, unsigned short sp) | |
485 | { | |
486 | unsigned long __user *intr_ptr; | |
487 | unsigned long segoffs; | |
488 | ||
489 | if (regs->cs == BIOSSEG) | |
490 | goto cannot_handle; | |
491 | if (is_revectored(i, &KVM86->int_revectored)) | |
492 | goto cannot_handle; | |
493 | if (i==0x21 && is_revectored(AH(regs),&KVM86->int21_revectored)) | |
494 | goto cannot_handle; | |
495 | intr_ptr = (unsigned long __user *) (i << 2); | |
496 | if (get_user(segoffs, intr_ptr)) | |
497 | goto cannot_handle; | |
498 | if ((segoffs >> 16) == BIOSSEG) | |
499 | goto cannot_handle; | |
500 | pushw(ssp, sp, get_vflags(regs), cannot_handle); | |
501 | pushw(ssp, sp, regs->cs, cannot_handle); | |
502 | pushw(ssp, sp, IP(regs), cannot_handle); | |
503 | regs->cs = segoffs >> 16; | |
504 | SP(regs) -= 6; | |
505 | IP(regs) = segoffs & 0xffff; | |
506 | clear_TF(regs); | |
507 | clear_IF(regs); | |
508 | clear_AC(regs); | |
509 | return; | |
510 | ||
511 | cannot_handle: | |
512 | return_to_32bit(regs, VM86_INTx + (i << 8)); | |
513 | } | |
514 | ||
515 | int handle_vm86_trap(struct kernel_vm86_regs * regs, long error_code, int trapno) | |
516 | { | |
517 | if (VMPI.is_vm86pus) { | |
518 | if ( (trapno==3) || (trapno==1) ) | |
519 | return_to_32bit(regs, VM86_TRAP + (trapno << 8)); | |
520 | do_int(regs, trapno, (unsigned char __user *) (regs->ss << 4), SP(regs)); | |
521 | return 0; | |
522 | } | |
523 | if (trapno !=1) | |
524 | return 1; /* we let this handle by the calling routine */ | |
525 | if (current->ptrace & PT_PTRACED) { | |
526 | unsigned long flags; | |
527 | spin_lock_irqsave(¤t->sighand->siglock, flags); | |
528 | sigdelset(¤t->blocked, SIGTRAP); | |
529 | recalc_sigpending(); | |
530 | spin_unlock_irqrestore(¤t->sighand->siglock, flags); | |
531 | } | |
532 | send_sig(SIGTRAP, current, 1); | |
533 | current->thread.trap_no = trapno; | |
534 | current->thread.error_code = error_code; | |
535 | return 0; | |
536 | } | |
537 | ||
538 | void handle_vm86_fault(struct kernel_vm86_regs * regs, long error_code) | |
539 | { | |
540 | unsigned char opcode; | |
541 | unsigned char __user *csp; | |
542 | unsigned char __user *ssp; | |
5fd75ebb | 543 | unsigned short ip, sp, orig_flags; |
1da177e4 LT |
544 | int data32, pref_done; |
545 | ||
546 | #define CHECK_IF_IN_TRAP \ | |
547 | if (VMPI.vm86dbg_active && VMPI.vm86dbg_TFpendig) \ | |
548 | newflags |= TF_MASK | |
549 | #define VM86_FAULT_RETURN do { \ | |
550 | if (VMPI.force_return_for_pic && (VEFLAGS & (IF_MASK | VIF_MASK))) \ | |
551 | return_to_32bit(regs, VM86_PICRETURN); \ | |
5fd75ebb PT |
552 | if (orig_flags & TF_MASK) \ |
553 | handle_vm86_trap(regs, 0, 1); \ | |
1da177e4 LT |
554 | return; } while (0) |
555 | ||
5fd75ebb PT |
556 | orig_flags = *(unsigned short *)®s->eflags; |
557 | ||
1da177e4 LT |
558 | csp = (unsigned char __user *) (regs->cs << 4); |
559 | ssp = (unsigned char __user *) (regs->ss << 4); | |
560 | sp = SP(regs); | |
561 | ip = IP(regs); | |
562 | ||
563 | data32 = 0; | |
564 | pref_done = 0; | |
565 | do { | |
566 | switch (opcode = popb(csp, ip, simulate_sigsegv)) { | |
567 | case 0x66: /* 32-bit data */ data32=1; break; | |
568 | case 0x67: /* 32-bit address */ break; | |
569 | case 0x2e: /* CS */ break; | |
570 | case 0x3e: /* DS */ break; | |
571 | case 0x26: /* ES */ break; | |
572 | case 0x36: /* SS */ break; | |
573 | case 0x65: /* GS */ break; | |
574 | case 0x64: /* FS */ break; | |
575 | case 0xf2: /* repnz */ break; | |
576 | case 0xf3: /* rep */ break; | |
577 | default: pref_done = 1; | |
578 | } | |
579 | } while (!pref_done); | |
580 | ||
581 | switch (opcode) { | |
582 | ||
583 | /* pushf */ | |
584 | case 0x9c: | |
585 | if (data32) { | |
586 | pushl(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
587 | SP(regs) -= 4; | |
588 | } else { | |
589 | pushw(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
590 | SP(regs) -= 2; | |
591 | } | |
592 | IP(regs) = ip; | |
593 | VM86_FAULT_RETURN; | |
594 | ||
595 | /* popf */ | |
596 | case 0x9d: | |
597 | { | |
598 | unsigned long newflags; | |
599 | if (data32) { | |
600 | newflags=popl(ssp, sp, simulate_sigsegv); | |
601 | SP(regs) += 4; | |
602 | } else { | |
603 | newflags = popw(ssp, sp, simulate_sigsegv); | |
604 | SP(regs) += 2; | |
605 | } | |
606 | IP(regs) = ip; | |
607 | CHECK_IF_IN_TRAP; | |
608 | if (data32) { | |
609 | set_vflags_long(newflags, regs); | |
610 | } else { | |
611 | set_vflags_short(newflags, regs); | |
612 | } | |
613 | VM86_FAULT_RETURN; | |
614 | } | |
615 | ||
616 | /* int xx */ | |
617 | case 0xcd: { | |
618 | int intno=popb(csp, ip, simulate_sigsegv); | |
619 | IP(regs) = ip; | |
620 | if (VMPI.vm86dbg_active) { | |
621 | if ( (1 << (intno &7)) & VMPI.vm86dbg_intxxtab[intno >> 3] ) | |
622 | return_to_32bit(regs, VM86_INTx + (intno << 8)); | |
623 | } | |
624 | do_int(regs, intno, ssp, sp); | |
625 | return; | |
626 | } | |
627 | ||
628 | /* iret */ | |
629 | case 0xcf: | |
630 | { | |
631 | unsigned long newip; | |
632 | unsigned long newcs; | |
633 | unsigned long newflags; | |
634 | if (data32) { | |
635 | newip=popl(ssp, sp, simulate_sigsegv); | |
636 | newcs=popl(ssp, sp, simulate_sigsegv); | |
637 | newflags=popl(ssp, sp, simulate_sigsegv); | |
638 | SP(regs) += 12; | |
639 | } else { | |
640 | newip = popw(ssp, sp, simulate_sigsegv); | |
641 | newcs = popw(ssp, sp, simulate_sigsegv); | |
642 | newflags = popw(ssp, sp, simulate_sigsegv); | |
643 | SP(regs) += 6; | |
644 | } | |
645 | IP(regs) = newip; | |
646 | regs->cs = newcs; | |
647 | CHECK_IF_IN_TRAP; | |
648 | if (data32) { | |
649 | set_vflags_long(newflags, regs); | |
650 | } else { | |
651 | set_vflags_short(newflags, regs); | |
652 | } | |
653 | VM86_FAULT_RETURN; | |
654 | } | |
655 | ||
656 | /* cli */ | |
657 | case 0xfa: | |
658 | IP(regs) = ip; | |
659 | clear_IF(regs); | |
660 | VM86_FAULT_RETURN; | |
661 | ||
662 | /* sti */ | |
663 | /* | |
664 | * Damn. This is incorrect: the 'sti' instruction should actually | |
665 | * enable interrupts after the /next/ instruction. Not good. | |
666 | * | |
667 | * Probably needs some horsing around with the TF flag. Aiee.. | |
668 | */ | |
669 | case 0xfb: | |
670 | IP(regs) = ip; | |
671 | set_IF(regs); | |
672 | VM86_FAULT_RETURN; | |
673 | ||
674 | default: | |
675 | return_to_32bit(regs, VM86_UNKNOWN); | |
676 | } | |
677 | ||
678 | return; | |
679 | ||
680 | simulate_sigsegv: | |
681 | /* FIXME: After a long discussion with Stas we finally | |
682 | * agreed, that this is wrong. Here we should | |
683 | * really send a SIGSEGV to the user program. | |
684 | * But how do we create the correct context? We | |
685 | * are inside a general protection fault handler | |
686 | * and has just returned from a page fault handler. | |
687 | * The correct context for the signal handler | |
688 | * should be a mixture of the two, but how do we | |
689 | * get the information? [KD] | |
690 | */ | |
691 | return_to_32bit(regs, VM86_UNKNOWN); | |
692 | } | |
693 | ||
694 | /* ---------------- vm86 special IRQ passing stuff ----------------- */ | |
695 | ||
696 | #define VM86_IRQNAME "vm86irq" | |
697 | ||
698 | static struct vm86_irqs { | |
699 | struct task_struct *tsk; | |
700 | int sig; | |
701 | } vm86_irqs[16]; | |
702 | ||
703 | static DEFINE_SPINLOCK(irqbits_lock); | |
704 | static int irqbits; | |
705 | ||
706 | #define ALLOWED_SIGS ( 1 /* 0 = don't send a signal */ \ | |
707 | | (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO) | (1 << SIGURG) \ | |
708 | | (1 << SIGUNUSED) ) | |
709 | ||
710 | static irqreturn_t irq_handler(int intno, void *dev_id, struct pt_regs * regs) | |
711 | { | |
712 | int irq_bit; | |
713 | unsigned long flags; | |
714 | ||
715 | spin_lock_irqsave(&irqbits_lock, flags); | |
716 | irq_bit = 1 << intno; | |
717 | if ((irqbits & irq_bit) || ! vm86_irqs[intno].tsk) | |
718 | goto out; | |
719 | irqbits |= irq_bit; | |
720 | if (vm86_irqs[intno].sig) | |
721 | send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1); | |
1da177e4 LT |
722 | /* |
723 | * IRQ will be re-enabled when user asks for the irq (whether | |
724 | * polling or as a result of the signal) | |
725 | */ | |
ad671423 PP |
726 | disable_irq_nosync(intno); |
727 | spin_unlock_irqrestore(&irqbits_lock, flags); | |
1da177e4 LT |
728 | return IRQ_HANDLED; |
729 | ||
730 | out: | |
731 | spin_unlock_irqrestore(&irqbits_lock, flags); | |
732 | return IRQ_NONE; | |
733 | } | |
734 | ||
735 | static inline void free_vm86_irq(int irqnumber) | |
736 | { | |
737 | unsigned long flags; | |
738 | ||
739 | free_irq(irqnumber, NULL); | |
740 | vm86_irqs[irqnumber].tsk = NULL; | |
741 | ||
742 | spin_lock_irqsave(&irqbits_lock, flags); | |
743 | irqbits &= ~(1 << irqnumber); | |
744 | spin_unlock_irqrestore(&irqbits_lock, flags); | |
745 | } | |
746 | ||
747 | void release_vm86_irqs(struct task_struct *task) | |
748 | { | |
749 | int i; | |
750 | for (i = FIRST_VM86_IRQ ; i <= LAST_VM86_IRQ; i++) | |
751 | if (vm86_irqs[i].tsk == task) | |
752 | free_vm86_irq(i); | |
753 | } | |
754 | ||
755 | static inline int get_and_reset_irq(int irqnumber) | |
756 | { | |
757 | int bit; | |
758 | unsigned long flags; | |
ad671423 | 759 | int ret = 0; |
1da177e4 LT |
760 | |
761 | if (invalid_vm86_irq(irqnumber)) return 0; | |
762 | if (vm86_irqs[irqnumber].tsk != current) return 0; | |
763 | spin_lock_irqsave(&irqbits_lock, flags); | |
764 | bit = irqbits & (1 << irqnumber); | |
765 | irqbits &= ~bit; | |
ad671423 PP |
766 | if (bit) { |
767 | enable_irq(irqnumber); | |
768 | ret = 1; | |
769 | } | |
770 | ||
1da177e4 | 771 | spin_unlock_irqrestore(&irqbits_lock, flags); |
ad671423 | 772 | return ret; |
1da177e4 LT |
773 | } |
774 | ||
775 | ||
776 | static int do_vm86_irq_handling(int subfunction, int irqnumber) | |
777 | { | |
778 | int ret; | |
779 | switch (subfunction) { | |
780 | case VM86_GET_AND_RESET_IRQ: { | |
781 | return get_and_reset_irq(irqnumber); | |
782 | } | |
783 | case VM86_GET_IRQ_BITS: { | |
784 | return irqbits; | |
785 | } | |
786 | case VM86_REQUEST_IRQ: { | |
787 | int sig = irqnumber >> 8; | |
788 | int irq = irqnumber & 255; | |
789 | if (!capable(CAP_SYS_ADMIN)) return -EPERM; | |
790 | if (!((1 << sig) & ALLOWED_SIGS)) return -EPERM; | |
791 | if (invalid_vm86_irq(irq)) return -EPERM; | |
792 | if (vm86_irqs[irq].tsk) return -EPERM; | |
793 | ret = request_irq(irq, &irq_handler, 0, VM86_IRQNAME, NULL); | |
794 | if (ret) return ret; | |
795 | vm86_irqs[irq].sig = sig; | |
796 | vm86_irqs[irq].tsk = current; | |
797 | return irq; | |
798 | } | |
799 | case VM86_FREE_IRQ: { | |
800 | if (invalid_vm86_irq(irqnumber)) return -EPERM; | |
801 | if (!vm86_irqs[irqnumber].tsk) return 0; | |
802 | if (vm86_irqs[irqnumber].tsk != current) return -EPERM; | |
803 | free_vm86_irq(irqnumber); | |
804 | return 0; | |
805 | } | |
806 | } | |
807 | return -EINVAL; | |
808 | } | |
809 |