Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 LT |
2 | * Copyright (C) 1994 Linus Torvalds |
3 | * | |
4 | * 29 dec 2001 - Fixed oopses caused by unchecked access to the vm86 | |
624dffcb | 5 | * stack - Manfred Spraul <manfred@colorfullife.com> |
1da177e4 LT |
6 | * |
7 | * 22 mar 2002 - Manfred detected the stackfaults, but didn't handle | |
8 | * them correctly. Now the emulation will be in a | |
9 | * consistent state after stackfaults - Kasper Dupont | |
10 | * <kasperd@daimi.au.dk> | |
11 | * | |
12 | * 22 mar 2002 - Added missing clear_IF in set_vflags_* Kasper Dupont | |
13 | * <kasperd@daimi.au.dk> | |
14 | * | |
15 | * ?? ??? 2002 - Fixed premature returns from handle_vm86_fault | |
16 | * caused by Kasper Dupont's changes - Stas Sergeev | |
17 | * | |
18 | * 4 apr 2002 - Fixed CHECK_IF_IN_TRAP broken by Stas' changes. | |
19 | * Kasper Dupont <kasperd@daimi.au.dk> | |
20 | * | |
21 | * 9 apr 2002 - Changed syntax of macros in handle_vm86_fault. | |
22 | * Kasper Dupont <kasperd@daimi.au.dk> | |
23 | * | |
24 | * 9 apr 2002 - Changed stack access macros to jump to a label | |
25 | * instead of returning to userspace. This simplifies | |
26 | * do_int, and is needed by handle_vm6_fault. Kasper | |
27 | * Dupont <kasperd@daimi.au.dk> | |
28 | * | |
29 | */ | |
30 | ||
c767a54b JP |
31 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
32 | ||
a9415644 | 33 | #include <linux/capability.h> |
1da177e4 LT |
34 | #include <linux/errno.h> |
35 | #include <linux/interrupt.h> | |
5522ddb3 | 36 | #include <linux/syscalls.h> |
1da177e4 LT |
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> | |
1da177e4 LT |
43 | #include <linux/highmem.h> |
44 | #include <linux/ptrace.h> | |
7e7f8a03 | 45 | #include <linux/audit.h> |
49d26b6e | 46 | #include <linux/stddef.h> |
1da177e4 LT |
47 | |
48 | #include <asm/uaccess.h> | |
49 | #include <asm/io.h> | |
50 | #include <asm/tlbflush.h> | |
51 | #include <asm/irq.h> | |
52 | ||
53 | /* | |
54 | * Known problems: | |
55 | * | |
56 | * Interrupt handling is not guaranteed: | |
57 | * - a real x86 will disable all interrupts for one instruction | |
58 | * after a "mov ss,xx" to make stack handling atomic even without | |
59 | * the 'lss' instruction. We can't guarantee this in v86 mode, | |
60 | * as the next instruction might result in a page fault or similar. | |
61 | * - a real x86 will have interrupts disabled for one instruction | |
62 | * past the 'sti' that enables them. We don't bother with all the | |
63 | * details yet. | |
64 | * | |
65 | * Let's hope these problems do not actually matter for anything. | |
66 | */ | |
67 | ||
68 | ||
69 | #define KVM86 ((struct kernel_vm86_struct *)regs) | |
83e714e8 | 70 | #define VMPI KVM86->vm86plus |
1da177e4 LT |
71 | |
72 | ||
73 | /* | |
74 | * 8- and 16-bit register defines.. | |
75 | */ | |
65ea5b03 PA |
76 | #define AL(regs) (((unsigned char *)&((regs)->pt.ax))[0]) |
77 | #define AH(regs) (((unsigned char *)&((regs)->pt.ax))[1]) | |
78 | #define IP(regs) (*(unsigned short *)&((regs)->pt.ip)) | |
79 | #define SP(regs) (*(unsigned short *)&((regs)->pt.sp)) | |
1da177e4 LT |
80 | |
81 | /* | |
82 | * virtual flags (16 and 32-bit versions) | |
83 | */ | |
84 | #define VFLAGS (*(unsigned short *)&(current->thread.v86flags)) | |
85 | #define VEFLAGS (current->thread.v86flags) | |
86 | ||
83e714e8 | 87 | #define set_flags(X, new, mask) \ |
1da177e4 LT |
88 | ((X) = ((X) & ~(mask)) | ((new) & (mask))) |
89 | ||
90 | #define SAFE_MASK (0xDD5) | |
91 | #define RETURN_MASK (0xDFF) | |
92 | ||
49d26b6e JF |
93 | /* convert kernel_vm86_regs to vm86_regs */ |
94 | static int copy_vm86_regs_to_user(struct vm86_regs __user *user, | |
95 | const struct kernel_vm86_regs *regs) | |
96 | { | |
97 | int ret = 0; | |
98 | ||
83e714e8 PC |
99 | /* |
100 | * kernel_vm86_regs is missing gs, so copy everything up to | |
101 | * (but not including) orig_eax, and then rest including orig_eax. | |
102 | */ | |
65ea5b03 PA |
103 | ret += copy_to_user(user, regs, offsetof(struct kernel_vm86_regs, pt.orig_ax)); |
104 | ret += copy_to_user(&user->orig_eax, ®s->pt.orig_ax, | |
49d26b6e | 105 | sizeof(struct kernel_vm86_regs) - |
65ea5b03 | 106 | offsetof(struct kernel_vm86_regs, pt.orig_ax)); |
49d26b6e JF |
107 | |
108 | return ret; | |
109 | } | |
110 | ||
111 | /* convert vm86_regs to kernel_vm86_regs */ | |
112 | static int copy_vm86_regs_from_user(struct kernel_vm86_regs *regs, | |
113 | const struct vm86_regs __user *user, | |
114 | unsigned extra) | |
115 | { | |
116 | int ret = 0; | |
117 | ||
65ea5b03 PA |
118 | /* copy ax-fs inclusive */ |
119 | ret += copy_from_user(regs, user, offsetof(struct kernel_vm86_regs, pt.orig_ax)); | |
120 | /* copy orig_ax-__gsh+extra */ | |
121 | ret += copy_from_user(®s->pt.orig_ax, &user->orig_eax, | |
49d26b6e | 122 | sizeof(struct kernel_vm86_regs) - |
65ea5b03 | 123 | offsetof(struct kernel_vm86_regs, pt.orig_ax) + |
49d26b6e | 124 | extra); |
49d26b6e JF |
125 | return ret; |
126 | } | |
1da177e4 | 127 | |
83e714e8 | 128 | struct pt_regs *save_v86_state(struct kernel_vm86_regs *regs) |
1da177e4 LT |
129 | { |
130 | struct tss_struct *tss; | |
131 | struct pt_regs *ret; | |
132 | unsigned long tmp; | |
133 | ||
134 | /* | |
135 | * This gets called from entry.S with interrupts disabled, but | |
136 | * from process context. Enable interrupts here, before trying | |
137 | * to access user space. | |
138 | */ | |
139 | local_irq_enable(); | |
140 | ||
141 | if (!current->thread.vm86_info) { | |
c767a54b | 142 | pr_alert("no vm86_info: BAD\n"); |
1da177e4 LT |
143 | do_exit(SIGSEGV); |
144 | } | |
a5c15d41 | 145 | set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | current->thread.v86mask); |
83e714e8 PC |
146 | tmp = copy_vm86_regs_to_user(¤t->thread.vm86_info->regs, regs); |
147 | tmp += put_user(current->thread.screen_bitmap, ¤t->thread.vm86_info->screen_bitmap); | |
1da177e4 | 148 | if (tmp) { |
c767a54b | 149 | pr_alert("could not access userspace vm86_info\n"); |
1da177e4 LT |
150 | do_exit(SIGSEGV); |
151 | } | |
152 | ||
24933b82 | 153 | tss = &per_cpu(cpu_tss, get_cpu()); |
faca6227 | 154 | current->thread.sp0 = current->thread.saved_sp0; |
1da177e4 | 155 | current->thread.sysenter_cs = __KERNEL_CS; |
faca6227 PA |
156 | load_sp0(tss, ¤t->thread); |
157 | current->thread.saved_sp0 = 0; | |
1da177e4 LT |
158 | put_cpu(); |
159 | ||
1da177e4 | 160 | ret = KVM86->regs32; |
49d26b6e | 161 | |
65ea5b03 | 162 | ret->fs = current->thread.saved_fs; |
d9a89a26 | 163 | set_user_gs(ret, current->thread.saved_gs); |
49d26b6e | 164 | |
1da177e4 LT |
165 | return ret; |
166 | } | |
167 | ||
60ec5585 | 168 | static void mark_screen_rdonly(struct mm_struct *mm) |
1da177e4 LT |
169 | { |
170 | pgd_t *pgd; | |
171 | pud_t *pud; | |
172 | pmd_t *pmd; | |
60ec5585 HD |
173 | pte_t *pte; |
174 | spinlock_t *ptl; | |
1da177e4 LT |
175 | int i; |
176 | ||
1a5a9906 | 177 | down_write(&mm->mmap_sem); |
60ec5585 | 178 | pgd = pgd_offset(mm, 0xA0000); |
1da177e4 LT |
179 | if (pgd_none_or_clear_bad(pgd)) |
180 | goto out; | |
181 | pud = pud_offset(pgd, 0xA0000); | |
182 | if (pud_none_or_clear_bad(pud)) | |
183 | goto out; | |
184 | pmd = pmd_offset(pud, 0xA0000); | |
e180377f | 185 | split_huge_page_pmd_mm(mm, 0xA0000, pmd); |
1da177e4 LT |
186 | if (pmd_none_or_clear_bad(pmd)) |
187 | goto out; | |
60ec5585 | 188 | pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); |
1da177e4 LT |
189 | for (i = 0; i < 32; i++) { |
190 | if (pte_present(*pte)) | |
191 | set_pte(pte, pte_wrprotect(*pte)); | |
192 | pte++; | |
193 | } | |
60ec5585 | 194 | pte_unmap_unlock(pte, ptl); |
1da177e4 | 195 | out: |
1a5a9906 | 196 | up_write(&mm->mmap_sem); |
1da177e4 LT |
197 | flush_tlb(); |
198 | } | |
199 | ||
200 | ||
201 | ||
202 | static int do_vm86_irq_handling(int subfunction, int irqnumber); | |
203 | static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk); | |
204 | ||
5522ddb3 | 205 | SYSCALL_DEFINE1(vm86old, struct vm86_struct __user *, v86) |
1da177e4 | 206 | { |
1da177e4 LT |
207 | struct kernel_vm86_struct info; /* declare this _on top_, |
208 | * this avoids wasting of stack space. | |
209 | * This remains on the stack until we | |
210 | * return to 32 bit user space. | |
211 | */ | |
5522ddb3 AH |
212 | struct task_struct *tsk = current; |
213 | int tmp; | |
1da177e4 | 214 | |
faca6227 | 215 | if (tsk->thread.saved_sp0) |
5522ddb3 | 216 | return -EPERM; |
49d26b6e JF |
217 | tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs, |
218 | offsetof(struct kernel_vm86_struct, vm86plus) - | |
219 | sizeof(info.regs)); | |
1da177e4 | 220 | if (tmp) |
5522ddb3 | 221 | return -EFAULT; |
1da177e4 | 222 | memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus); |
49cb25e9 | 223 | info.regs32 = current_pt_regs(); |
1da177e4 LT |
224 | tsk->thread.vm86_info = v86; |
225 | do_sys_vm86(&info, tsk); | |
5522ddb3 | 226 | return 0; /* we never return here */ |
1da177e4 LT |
227 | } |
228 | ||
229 | ||
5522ddb3 | 230 | SYSCALL_DEFINE2(vm86, unsigned long, cmd, unsigned long, arg) |
1da177e4 LT |
231 | { |
232 | struct kernel_vm86_struct info; /* declare this _on top_, | |
233 | * this avoids wasting of stack space. | |
234 | * This remains on the stack until we | |
235 | * return to 32 bit user space. | |
236 | */ | |
237 | struct task_struct *tsk; | |
5522ddb3 | 238 | int tmp; |
1da177e4 LT |
239 | struct vm86plus_struct __user *v86; |
240 | ||
241 | tsk = current; | |
f1382f15 | 242 | switch (cmd) { |
83e714e8 PC |
243 | case VM86_REQUEST_IRQ: |
244 | case VM86_FREE_IRQ: | |
245 | case VM86_GET_IRQ_BITS: | |
246 | case VM86_GET_AND_RESET_IRQ: | |
5522ddb3 | 247 | return do_vm86_irq_handling(cmd, (int)arg); |
83e714e8 PC |
248 | case VM86_PLUS_INSTALL_CHECK: |
249 | /* | |
250 | * NOTE: on old vm86 stuff this will return the error | |
251 | * from access_ok(), because the subfunction is | |
252 | * interpreted as (invalid) address to vm86_struct. | |
253 | * So the installation check works. | |
254 | */ | |
5522ddb3 | 255 | return 0; |
1da177e4 LT |
256 | } |
257 | ||
258 | /* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */ | |
faca6227 | 259 | if (tsk->thread.saved_sp0) |
5522ddb3 | 260 | return -EPERM; |
f1382f15 | 261 | v86 = (struct vm86plus_struct __user *)arg; |
49d26b6e JF |
262 | tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs, |
263 | offsetof(struct kernel_vm86_struct, regs32) - | |
264 | sizeof(info.regs)); | |
1da177e4 | 265 | if (tmp) |
5522ddb3 | 266 | return -EFAULT; |
49cb25e9 | 267 | info.regs32 = current_pt_regs(); |
1da177e4 LT |
268 | info.vm86plus.is_vm86pus = 1; |
269 | tsk->thread.vm86_info = (struct vm86_struct __user *)v86; | |
270 | do_sys_vm86(&info, tsk); | |
5522ddb3 | 271 | return 0; /* we never return here */ |
1da177e4 LT |
272 | } |
273 | ||
274 | ||
275 | static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk) | |
276 | { | |
277 | struct tss_struct *tss; | |
278 | /* | |
279 | * make sure the vm86() system call doesn't try to do anything silly | |
280 | */ | |
65ea5b03 PA |
281 | info->regs.pt.ds = 0; |
282 | info->regs.pt.es = 0; | |
283 | info->regs.pt.fs = 0; | |
3aa6b186 LR |
284 | #ifndef CONFIG_X86_32_LAZY_GS |
285 | info->regs.pt.gs = 0; | |
286 | #endif | |
1da177e4 LT |
287 | |
288 | /* | |
65ea5b03 | 289 | * The flags register is also special: we cannot trust that the user |
1da177e4 LT |
290 | * has set it up safely, so this makes sure interrupt etc flags are |
291 | * inherited from protected mode. | |
292 | */ | |
65ea5b03 PA |
293 | VEFLAGS = info->regs.pt.flags; |
294 | info->regs.pt.flags &= SAFE_MASK; | |
295 | info->regs.pt.flags |= info->regs32->flags & ~SAFE_MASK; | |
6b6891f9 | 296 | info->regs.pt.flags |= X86_VM_MASK; |
1da177e4 LT |
297 | |
298 | switch (info->cpu_type) { | |
83e714e8 PC |
299 | case CPU_286: |
300 | tsk->thread.v86mask = 0; | |
301 | break; | |
302 | case CPU_386: | |
a5c15d41 | 303 | tsk->thread.v86mask = X86_EFLAGS_NT | X86_EFLAGS_IOPL; |
83e714e8 PC |
304 | break; |
305 | case CPU_486: | |
a5c15d41 | 306 | tsk->thread.v86mask = X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL; |
83e714e8 PC |
307 | break; |
308 | default: | |
a5c15d41 | 309 | tsk->thread.v86mask = X86_EFLAGS_ID | X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL; |
83e714e8 | 310 | break; |
1da177e4 LT |
311 | } |
312 | ||
313 | /* | |
975e5f45 | 314 | * Save old state, set default return value (%ax) to 0 (VM86_SIGNAL) |
1da177e4 | 315 | */ |
975e5f45 | 316 | info->regs32->ax = VM86_SIGNAL; |
faca6227 | 317 | tsk->thread.saved_sp0 = tsk->thread.sp0; |
65ea5b03 | 318 | tsk->thread.saved_fs = info->regs32->fs; |
d9a89a26 | 319 | tsk->thread.saved_gs = get_user_gs(info->regs32); |
1da177e4 | 320 | |
24933b82 | 321 | tss = &per_cpu(cpu_tss, get_cpu()); |
faca6227 | 322 | tsk->thread.sp0 = (unsigned long) &info->VM86_TSS_ESP0; |
1da177e4 LT |
323 | if (cpu_has_sep) |
324 | tsk->thread.sysenter_cs = 0; | |
faca6227 | 325 | load_sp0(tss, &tsk->thread); |
1da177e4 LT |
326 | put_cpu(); |
327 | ||
328 | tsk->thread.screen_bitmap = info->screen_bitmap; | |
329 | if (info->flags & VM86_SCREEN_BITMAP) | |
60ec5585 | 330 | mark_screen_rdonly(tsk->mm); |
7e7f8a03 | 331 | |
d7e7528b | 332 | /*call __audit_syscall_exit since we do not exit via the normal paths */ |
6015ff10 | 333 | #ifdef CONFIG_AUDITSYSCALL |
7e7f8a03 | 334 | if (unlikely(current->audit_context)) |
d7e7528b | 335 | __audit_syscall_exit(1, 0); |
6015ff10 | 336 | #endif |
7e7f8a03 | 337 | |
1da177e4 | 338 | __asm__ __volatile__( |
1da177e4 LT |
339 | "movl %0,%%esp\n\t" |
340 | "movl %1,%%ebp\n\t" | |
3aa6b186 | 341 | #ifdef CONFIG_X86_32_LAZY_GS |
464d1a78 | 342 | "mov %2, %%gs\n\t" |
3aa6b186 | 343 | #endif |
1da177e4 LT |
344 | "jmp resume_userspace" |
345 | : /* no outputs */ | |
49d26b6e | 346 | :"r" (&info->regs), "r" (task_thread_info(tsk)), "r" (0)); |
1da177e4 LT |
347 | /* we never return here */ |
348 | } | |
349 | ||
83e714e8 | 350 | static inline void return_to_32bit(struct kernel_vm86_regs *regs16, int retval) |
1da177e4 | 351 | { |
83e714e8 | 352 | struct pt_regs *regs32; |
1da177e4 LT |
353 | |
354 | regs32 = save_v86_state(regs16); | |
65ea5b03 | 355 | regs32->ax = retval; |
1da177e4 LT |
356 | __asm__ __volatile__("movl %0,%%esp\n\t" |
357 | "movl %1,%%ebp\n\t" | |
358 | "jmp resume_userspace" | |
359 | : : "r" (regs32), "r" (current_thread_info())); | |
360 | } | |
361 | ||
83e714e8 | 362 | static inline void set_IF(struct kernel_vm86_regs *regs) |
1da177e4 | 363 | { |
a5c15d41 | 364 | VEFLAGS |= X86_EFLAGS_VIF; |
365 | if (VEFLAGS & X86_EFLAGS_VIP) | |
1da177e4 LT |
366 | return_to_32bit(regs, VM86_STI); |
367 | } | |
368 | ||
83e714e8 | 369 | static inline void clear_IF(struct kernel_vm86_regs *regs) |
1da177e4 | 370 | { |
a5c15d41 | 371 | VEFLAGS &= ~X86_EFLAGS_VIF; |
1da177e4 LT |
372 | } |
373 | ||
83e714e8 | 374 | static inline void clear_TF(struct kernel_vm86_regs *regs) |
1da177e4 | 375 | { |
a5c15d41 | 376 | regs->pt.flags &= ~X86_EFLAGS_TF; |
1da177e4 LT |
377 | } |
378 | ||
83e714e8 | 379 | static inline void clear_AC(struct kernel_vm86_regs *regs) |
1da177e4 | 380 | { |
a5c15d41 | 381 | regs->pt.flags &= ~X86_EFLAGS_AC; |
1da177e4 LT |
382 | } |
383 | ||
83e714e8 PC |
384 | /* |
385 | * It is correct to call set_IF(regs) from the set_vflags_* | |
1da177e4 LT |
386 | * functions. However someone forgot to call clear_IF(regs) |
387 | * in the opposite case. | |
388 | * After the command sequence CLI PUSHF STI POPF you should | |
ab4a574e | 389 | * end up with interrupts disabled, but you ended up with |
1da177e4 LT |
390 | * interrupts enabled. |
391 | * ( I was testing my own changes, but the only bug I | |
392 | * could find was in a function I had not changed. ) | |
393 | * [KD] | |
394 | */ | |
395 | ||
83e714e8 | 396 | static inline void set_vflags_long(unsigned long flags, struct kernel_vm86_regs *regs) |
1da177e4 | 397 | { |
65ea5b03 PA |
398 | set_flags(VEFLAGS, flags, current->thread.v86mask); |
399 | set_flags(regs->pt.flags, flags, SAFE_MASK); | |
a5c15d41 | 400 | if (flags & X86_EFLAGS_IF) |
1da177e4 LT |
401 | set_IF(regs); |
402 | else | |
403 | clear_IF(regs); | |
404 | } | |
405 | ||
83e714e8 | 406 | static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs *regs) |
1da177e4 LT |
407 | { |
408 | set_flags(VFLAGS, flags, current->thread.v86mask); | |
65ea5b03 | 409 | set_flags(regs->pt.flags, flags, SAFE_MASK); |
a5c15d41 | 410 | if (flags & X86_EFLAGS_IF) |
1da177e4 LT |
411 | set_IF(regs); |
412 | else | |
413 | clear_IF(regs); | |
414 | } | |
415 | ||
83e714e8 | 416 | static inline unsigned long get_vflags(struct kernel_vm86_regs *regs) |
1da177e4 | 417 | { |
65ea5b03 | 418 | unsigned long flags = regs->pt.flags & RETURN_MASK; |
1da177e4 | 419 | |
a5c15d41 | 420 | if (VEFLAGS & X86_EFLAGS_VIF) |
421 | flags |= X86_EFLAGS_IF; | |
422 | flags |= X86_EFLAGS_IOPL; | |
1da177e4 LT |
423 | return flags | (VEFLAGS & current->thread.v86mask); |
424 | } | |
425 | ||
83e714e8 | 426 | static inline int is_revectored(int nr, struct revectored_struct *bitmap) |
1da177e4 LT |
427 | { |
428 | __asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0" | |
429 | :"=r" (nr) | |
83e714e8 | 430 | :"m" (*bitmap), "r" (nr)); |
1da177e4 LT |
431 | return nr; |
432 | } | |
433 | ||
434 | #define val_byte(val, n) (((__u8 *)&val)[n]) | |
435 | ||
436 | #define pushb(base, ptr, val, err_label) \ | |
437 | do { \ | |
438 | __u8 __val = val; \ | |
439 | ptr--; \ | |
440 | if (put_user(__val, base + ptr) < 0) \ | |
441 | goto err_label; \ | |
83e714e8 | 442 | } while (0) |
1da177e4 LT |
443 | |
444 | #define pushw(base, ptr, val, err_label) \ | |
445 | do { \ | |
446 | __u16 __val = val; \ | |
447 | ptr--; \ | |
448 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
449 | goto err_label; \ | |
450 | ptr--; \ | |
451 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
452 | goto err_label; \ | |
83e714e8 | 453 | } while (0) |
1da177e4 LT |
454 | |
455 | #define pushl(base, ptr, val, err_label) \ | |
456 | do { \ | |
457 | __u32 __val = val; \ | |
458 | ptr--; \ | |
459 | if (put_user(val_byte(__val, 3), base + ptr) < 0) \ | |
460 | goto err_label; \ | |
461 | ptr--; \ | |
462 | if (put_user(val_byte(__val, 2), base + ptr) < 0) \ | |
463 | goto err_label; \ | |
464 | ptr--; \ | |
465 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
466 | goto err_label; \ | |
467 | ptr--; \ | |
468 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
469 | goto err_label; \ | |
83e714e8 | 470 | } while (0) |
1da177e4 LT |
471 | |
472 | #define popb(base, ptr, err_label) \ | |
473 | ({ \ | |
474 | __u8 __res; \ | |
475 | if (get_user(__res, base + ptr) < 0) \ | |
476 | goto err_label; \ | |
477 | ptr++; \ | |
478 | __res; \ | |
479 | }) | |
480 | ||
481 | #define popw(base, ptr, err_label) \ | |
482 | ({ \ | |
483 | __u16 __res; \ | |
484 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
485 | goto err_label; \ | |
486 | ptr++; \ | |
487 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
488 | goto err_label; \ | |
489 | ptr++; \ | |
490 | __res; \ | |
491 | }) | |
492 | ||
493 | #define popl(base, ptr, err_label) \ | |
494 | ({ \ | |
495 | __u32 __res; \ | |
496 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
497 | goto err_label; \ | |
498 | ptr++; \ | |
499 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
500 | goto err_label; \ | |
501 | ptr++; \ | |
502 | if (get_user(val_byte(__res, 2), base + ptr) < 0) \ | |
503 | goto err_label; \ | |
504 | ptr++; \ | |
505 | if (get_user(val_byte(__res, 3), base + ptr) < 0) \ | |
506 | goto err_label; \ | |
507 | ptr++; \ | |
508 | __res; \ | |
509 | }) | |
510 | ||
511 | /* There are so many possible reasons for this function to return | |
512 | * VM86_INTx, so adding another doesn't bother me. We can expect | |
513 | * userspace programs to be able to handle it. (Getting a problem | |
514 | * in userspace is always better than an Oops anyway.) [KD] | |
515 | */ | |
516 | static void do_int(struct kernel_vm86_regs *regs, int i, | |
83e714e8 | 517 | unsigned char __user *ssp, unsigned short sp) |
1da177e4 LT |
518 | { |
519 | unsigned long __user *intr_ptr; | |
520 | unsigned long segoffs; | |
521 | ||
65ea5b03 | 522 | if (regs->pt.cs == BIOSSEG) |
1da177e4 LT |
523 | goto cannot_handle; |
524 | if (is_revectored(i, &KVM86->int_revectored)) | |
525 | goto cannot_handle; | |
83e714e8 | 526 | if (i == 0x21 && is_revectored(AH(regs), &KVM86->int21_revectored)) |
1da177e4 LT |
527 | goto cannot_handle; |
528 | intr_ptr = (unsigned long __user *) (i << 2); | |
529 | if (get_user(segoffs, intr_ptr)) | |
530 | goto cannot_handle; | |
531 | if ((segoffs >> 16) == BIOSSEG) | |
532 | goto cannot_handle; | |
533 | pushw(ssp, sp, get_vflags(regs), cannot_handle); | |
65ea5b03 | 534 | pushw(ssp, sp, regs->pt.cs, cannot_handle); |
1da177e4 | 535 | pushw(ssp, sp, IP(regs), cannot_handle); |
65ea5b03 | 536 | regs->pt.cs = segoffs >> 16; |
1da177e4 LT |
537 | SP(regs) -= 6; |
538 | IP(regs) = segoffs & 0xffff; | |
539 | clear_TF(regs); | |
540 | clear_IF(regs); | |
541 | clear_AC(regs); | |
542 | return; | |
543 | ||
544 | cannot_handle: | |
545 | return_to_32bit(regs, VM86_INTx + (i << 8)); | |
546 | } | |
547 | ||
83e714e8 | 548 | int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno) |
1da177e4 LT |
549 | { |
550 | if (VMPI.is_vm86pus) { | |
6554287b BO |
551 | if ((trapno == 3) || (trapno == 1)) { |
552 | KVM86->regs32->ax = VM86_TRAP + (trapno << 8); | |
553 | /* setting this flag forces the code in entry_32.S to | |
e76623d6 AV |
554 | the path where we call save_v86_state() and change |
555 | the stack pointer to KVM86->regs32 */ | |
556 | set_thread_flag(TIF_NOTIFY_RESUME); | |
6554287b BO |
557 | return 0; |
558 | } | |
65ea5b03 | 559 | do_int(regs, trapno, (unsigned char __user *) (regs->pt.ss << 4), SP(regs)); |
1da177e4 LT |
560 | return 0; |
561 | } | |
83e714e8 | 562 | if (trapno != 1) |
1da177e4 | 563 | return 1; /* we let this handle by the calling routine */ |
51e7dc70 | 564 | current->thread.trap_nr = trapno; |
1da177e4 | 565 | current->thread.error_code = error_code; |
0f540910 | 566 | force_sig(SIGTRAP, current); |
1da177e4 LT |
567 | return 0; |
568 | } | |
569 | ||
83e714e8 | 570 | void handle_vm86_fault(struct kernel_vm86_regs *regs, long error_code) |
1da177e4 LT |
571 | { |
572 | unsigned char opcode; | |
573 | unsigned char __user *csp; | |
574 | unsigned char __user *ssp; | |
5fd75ebb | 575 | unsigned short ip, sp, orig_flags; |
1da177e4 LT |
576 | int data32, pref_done; |
577 | ||
578 | #define CHECK_IF_IN_TRAP \ | |
579 | if (VMPI.vm86dbg_active && VMPI.vm86dbg_TFpendig) \ | |
a5c15d41 | 580 | newflags |= X86_EFLAGS_TF |
1da177e4 | 581 | #define VM86_FAULT_RETURN do { \ |
a5c15d41 | 582 | if (VMPI.force_return_for_pic && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) \ |
1da177e4 | 583 | return_to_32bit(regs, VM86_PICRETURN); \ |
a5c15d41 | 584 | if (orig_flags & X86_EFLAGS_TF) \ |
5fd75ebb | 585 | handle_vm86_trap(regs, 0, 1); \ |
1da177e4 LT |
586 | return; } while (0) |
587 | ||
65ea5b03 | 588 | orig_flags = *(unsigned short *)®s->pt.flags; |
5fd75ebb | 589 | |
65ea5b03 PA |
590 | csp = (unsigned char __user *) (regs->pt.cs << 4); |
591 | ssp = (unsigned char __user *) (regs->pt.ss << 4); | |
1da177e4 LT |
592 | sp = SP(regs); |
593 | ip = IP(regs); | |
594 | ||
595 | data32 = 0; | |
596 | pref_done = 0; | |
597 | do { | |
598 | switch (opcode = popb(csp, ip, simulate_sigsegv)) { | |
83e714e8 PC |
599 | case 0x66: /* 32-bit data */ data32 = 1; break; |
600 | case 0x67: /* 32-bit address */ break; | |
601 | case 0x2e: /* CS */ break; | |
602 | case 0x3e: /* DS */ break; | |
603 | case 0x26: /* ES */ break; | |
604 | case 0x36: /* SS */ break; | |
605 | case 0x65: /* GS */ break; | |
606 | case 0x64: /* FS */ break; | |
607 | case 0xf2: /* repnz */ break; | |
608 | case 0xf3: /* rep */ break; | |
609 | default: pref_done = 1; | |
1da177e4 LT |
610 | } |
611 | } while (!pref_done); | |
612 | ||
613 | switch (opcode) { | |
614 | ||
615 | /* pushf */ | |
616 | case 0x9c: | |
617 | if (data32) { | |
618 | pushl(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
619 | SP(regs) -= 4; | |
620 | } else { | |
621 | pushw(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
622 | SP(regs) -= 2; | |
623 | } | |
624 | IP(regs) = ip; | |
625 | VM86_FAULT_RETURN; | |
626 | ||
627 | /* popf */ | |
628 | case 0x9d: | |
629 | { | |
630 | unsigned long newflags; | |
631 | if (data32) { | |
83e714e8 | 632 | newflags = popl(ssp, sp, simulate_sigsegv); |
1da177e4 LT |
633 | SP(regs) += 4; |
634 | } else { | |
635 | newflags = popw(ssp, sp, simulate_sigsegv); | |
636 | SP(regs) += 2; | |
637 | } | |
638 | IP(regs) = ip; | |
639 | CHECK_IF_IN_TRAP; | |
83e714e8 | 640 | if (data32) |
1da177e4 | 641 | set_vflags_long(newflags, regs); |
83e714e8 | 642 | else |
1da177e4 | 643 | set_vflags_short(newflags, regs); |
83e714e8 | 644 | |
1da177e4 LT |
645 | VM86_FAULT_RETURN; |
646 | } | |
647 | ||
648 | /* int xx */ | |
649 | case 0xcd: { | |
83e714e8 | 650 | int intno = popb(csp, ip, simulate_sigsegv); |
1da177e4 LT |
651 | IP(regs) = ip; |
652 | if (VMPI.vm86dbg_active) { | |
83e714e8 | 653 | if ((1 << (intno & 7)) & VMPI.vm86dbg_intxxtab[intno >> 3]) |
1da177e4 LT |
654 | return_to_32bit(regs, VM86_INTx + (intno << 8)); |
655 | } | |
656 | do_int(regs, intno, ssp, sp); | |
657 | return; | |
658 | } | |
659 | ||
660 | /* iret */ | |
661 | case 0xcf: | |
662 | { | |
663 | unsigned long newip; | |
664 | unsigned long newcs; | |
665 | unsigned long newflags; | |
666 | if (data32) { | |
83e714e8 PC |
667 | newip = popl(ssp, sp, simulate_sigsegv); |
668 | newcs = popl(ssp, sp, simulate_sigsegv); | |
669 | newflags = popl(ssp, sp, simulate_sigsegv); | |
1da177e4 LT |
670 | SP(regs) += 12; |
671 | } else { | |
672 | newip = popw(ssp, sp, simulate_sigsegv); | |
673 | newcs = popw(ssp, sp, simulate_sigsegv); | |
674 | newflags = popw(ssp, sp, simulate_sigsegv); | |
675 | SP(regs) += 6; | |
676 | } | |
677 | IP(regs) = newip; | |
65ea5b03 | 678 | regs->pt.cs = newcs; |
1da177e4 LT |
679 | CHECK_IF_IN_TRAP; |
680 | if (data32) { | |
681 | set_vflags_long(newflags, regs); | |
682 | } else { | |
683 | set_vflags_short(newflags, regs); | |
684 | } | |
685 | VM86_FAULT_RETURN; | |
686 | } | |
687 | ||
688 | /* cli */ | |
689 | case 0xfa: | |
690 | IP(regs) = ip; | |
691 | clear_IF(regs); | |
692 | VM86_FAULT_RETURN; | |
693 | ||
694 | /* sti */ | |
695 | /* | |
696 | * Damn. This is incorrect: the 'sti' instruction should actually | |
697 | * enable interrupts after the /next/ instruction. Not good. | |
698 | * | |
699 | * Probably needs some horsing around with the TF flag. Aiee.. | |
700 | */ | |
701 | case 0xfb: | |
702 | IP(regs) = ip; | |
703 | set_IF(regs); | |
704 | VM86_FAULT_RETURN; | |
705 | ||
706 | default: | |
707 | return_to_32bit(regs, VM86_UNKNOWN); | |
708 | } | |
709 | ||
710 | return; | |
711 | ||
712 | simulate_sigsegv: | |
713 | /* FIXME: After a long discussion with Stas we finally | |
714 | * agreed, that this is wrong. Here we should | |
715 | * really send a SIGSEGV to the user program. | |
716 | * But how do we create the correct context? We | |
717 | * are inside a general protection fault handler | |
718 | * and has just returned from a page fault handler. | |
719 | * The correct context for the signal handler | |
720 | * should be a mixture of the two, but how do we | |
721 | * get the information? [KD] | |
722 | */ | |
723 | return_to_32bit(regs, VM86_UNKNOWN); | |
724 | } | |
725 | ||
726 | /* ---------------- vm86 special IRQ passing stuff ----------------- */ | |
727 | ||
728 | #define VM86_IRQNAME "vm86irq" | |
729 | ||
730 | static struct vm86_irqs { | |
731 | struct task_struct *tsk; | |
732 | int sig; | |
733 | } vm86_irqs[16]; | |
734 | ||
735 | static DEFINE_SPINLOCK(irqbits_lock); | |
736 | static int irqbits; | |
737 | ||
83e714e8 | 738 | #define ALLOWED_SIGS (1 /* 0 = don't send a signal */ \ |
1da177e4 | 739 | | (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO) | (1 << SIGURG) \ |
83e714e8 PC |
740 | | (1 << SIGUNUSED)) |
741 | ||
7d12e780 | 742 | static irqreturn_t irq_handler(int intno, void *dev_id) |
1da177e4 LT |
743 | { |
744 | int irq_bit; | |
745 | unsigned long flags; | |
746 | ||
83e714e8 | 747 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 | 748 | irq_bit = 1 << intno; |
83e714e8 | 749 | if ((irqbits & irq_bit) || !vm86_irqs[intno].tsk) |
1da177e4 LT |
750 | goto out; |
751 | irqbits |= irq_bit; | |
752 | if (vm86_irqs[intno].sig) | |
753 | send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1); | |
1da177e4 LT |
754 | /* |
755 | * IRQ will be re-enabled when user asks for the irq (whether | |
756 | * polling or as a result of the signal) | |
757 | */ | |
ad671423 PP |
758 | disable_irq_nosync(intno); |
759 | spin_unlock_irqrestore(&irqbits_lock, flags); | |
1da177e4 LT |
760 | return IRQ_HANDLED; |
761 | ||
762 | out: | |
83e714e8 | 763 | spin_unlock_irqrestore(&irqbits_lock, flags); |
1da177e4 LT |
764 | return IRQ_NONE; |
765 | } | |
766 | ||
767 | static inline void free_vm86_irq(int irqnumber) | |
768 | { | |
769 | unsigned long flags; | |
770 | ||
771 | free_irq(irqnumber, NULL); | |
772 | vm86_irqs[irqnumber].tsk = NULL; | |
773 | ||
83e714e8 | 774 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 | 775 | irqbits &= ~(1 << irqnumber); |
83e714e8 | 776 | spin_unlock_irqrestore(&irqbits_lock, flags); |
1da177e4 LT |
777 | } |
778 | ||
779 | void release_vm86_irqs(struct task_struct *task) | |
780 | { | |
781 | int i; | |
782 | for (i = FIRST_VM86_IRQ ; i <= LAST_VM86_IRQ; i++) | |
783 | if (vm86_irqs[i].tsk == task) | |
784 | free_vm86_irq(i); | |
785 | } | |
786 | ||
787 | static inline int get_and_reset_irq(int irqnumber) | |
788 | { | |
789 | int bit; | |
790 | unsigned long flags; | |
ad671423 | 791 | int ret = 0; |
83e714e8 | 792 | |
1da177e4 LT |
793 | if (invalid_vm86_irq(irqnumber)) return 0; |
794 | if (vm86_irqs[irqnumber].tsk != current) return 0; | |
83e714e8 | 795 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 LT |
796 | bit = irqbits & (1 << irqnumber); |
797 | irqbits &= ~bit; | |
ad671423 PP |
798 | if (bit) { |
799 | enable_irq(irqnumber); | |
800 | ret = 1; | |
801 | } | |
802 | ||
83e714e8 | 803 | spin_unlock_irqrestore(&irqbits_lock, flags); |
ad671423 | 804 | return ret; |
1da177e4 LT |
805 | } |
806 | ||
807 | ||
808 | static int do_vm86_irq_handling(int subfunction, int irqnumber) | |
809 | { | |
810 | int ret; | |
811 | switch (subfunction) { | |
812 | case VM86_GET_AND_RESET_IRQ: { | |
813 | return get_and_reset_irq(irqnumber); | |
814 | } | |
815 | case VM86_GET_IRQ_BITS: { | |
816 | return irqbits; | |
817 | } | |
818 | case VM86_REQUEST_IRQ: { | |
819 | int sig = irqnumber >> 8; | |
820 | int irq = irqnumber & 255; | |
821 | if (!capable(CAP_SYS_ADMIN)) return -EPERM; | |
822 | if (!((1 << sig) & ALLOWED_SIGS)) return -EPERM; | |
823 | if (invalid_vm86_irq(irq)) return -EPERM; | |
824 | if (vm86_irqs[irq].tsk) return -EPERM; | |
825 | ret = request_irq(irq, &irq_handler, 0, VM86_IRQNAME, NULL); | |
826 | if (ret) return ret; | |
827 | vm86_irqs[irq].sig = sig; | |
828 | vm86_irqs[irq].tsk = current; | |
829 | return irq; | |
830 | } | |
831 | case VM86_FREE_IRQ: { | |
832 | if (invalid_vm86_irq(irqnumber)) return -EPERM; | |
833 | if (!vm86_irqs[irqnumber].tsk) return 0; | |
834 | if (vm86_irqs[irqnumber].tsk != current) return -EPERM; | |
835 | free_vm86_irq(irqnumber); | |
836 | return 0; | |
837 | } | |
838 | } | |
839 | return -EINVAL; | |
840 | } | |
841 |