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Commit | Line | Data |
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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 | 37 | #include <linux/sched.h> |
68db0cf1 | 38 | #include <linux/sched/task_stack.h> |
1da177e4 LT |
39 | #include <linux/kernel.h> |
40 | #include <linux/signal.h> | |
41 | #include <linux/string.h> | |
42 | #include <linux/mm.h> | |
43 | #include <linux/smp.h> | |
1da177e4 LT |
44 | #include <linux/highmem.h> |
45 | #include <linux/ptrace.h> | |
7e7f8a03 | 46 | #include <linux/audit.h> |
49d26b6e | 47 | #include <linux/stddef.h> |
9fda6a06 | 48 | #include <linux/slab.h> |
76fc5e7b | 49 | #include <linux/security.h> |
1da177e4 | 50 | |
7c0f6ba6 | 51 | #include <linux/uaccess.h> |
1da177e4 LT |
52 | #include <asm/io.h> |
53 | #include <asm/tlbflush.h> | |
54 | #include <asm/irq.h> | |
5ed92a8a | 55 | #include <asm/traps.h> |
ba3e127e | 56 | #include <asm/vm86.h> |
779e32d0 | 57 | #include <asm/switch_to.h> |
1da177e4 LT |
58 | |
59 | /* | |
60 | * Known problems: | |
61 | * | |
62 | * Interrupt handling is not guaranteed: | |
63 | * - a real x86 will disable all interrupts for one instruction | |
64 | * after a "mov ss,xx" to make stack handling atomic even without | |
65 | * the 'lss' instruction. We can't guarantee this in v86 mode, | |
66 | * as the next instruction might result in a page fault or similar. | |
67 | * - a real x86 will have interrupts disabled for one instruction | |
68 | * past the 'sti' that enables them. We don't bother with all the | |
69 | * details yet. | |
70 | * | |
71 | * Let's hope these problems do not actually matter for anything. | |
72 | */ | |
73 | ||
74 | ||
1da177e4 LT |
75 | /* |
76 | * 8- and 16-bit register defines.. | |
77 | */ | |
65ea5b03 PA |
78 | #define AL(regs) (((unsigned char *)&((regs)->pt.ax))[0]) |
79 | #define AH(regs) (((unsigned char *)&((regs)->pt.ax))[1]) | |
80 | #define IP(regs) (*(unsigned short *)&((regs)->pt.ip)) | |
81 | #define SP(regs) (*(unsigned short *)&((regs)->pt.sp)) | |
1da177e4 LT |
82 | |
83 | /* | |
84 | * virtual flags (16 and 32-bit versions) | |
85 | */ | |
decd275e BG |
86 | #define VFLAGS (*(unsigned short *)&(current->thread.vm86->veflags)) |
87 | #define VEFLAGS (current->thread.vm86->veflags) | |
1da177e4 | 88 | |
83e714e8 | 89 | #define set_flags(X, new, mask) \ |
1da177e4 LT |
90 | ((X) = ((X) & ~(mask)) | ((new) & (mask))) |
91 | ||
92 | #define SAFE_MASK (0xDD5) | |
93 | #define RETURN_MASK (0xDFF) | |
94 | ||
5ed92a8a | 95 | void save_v86_state(struct kernel_vm86_regs *regs, int retval) |
1da177e4 | 96 | { |
ed0b2edb BG |
97 | struct task_struct *tsk = current; |
98 | struct vm86plus_struct __user *user; | |
9fda6a06 | 99 | struct vm86 *vm86 = current->thread.vm86; |
ed0b2edb | 100 | long err = 0; |
1da177e4 LT |
101 | |
102 | /* | |
103 | * This gets called from entry.S with interrupts disabled, but | |
104 | * from process context. Enable interrupts here, before trying | |
105 | * to access user space. | |
106 | */ | |
107 | local_irq_enable(); | |
108 | ||
13426356 BG |
109 | if (!vm86 || !vm86->user_vm86) { |
110 | pr_alert("no user_vm86: BAD\n"); | |
1da177e4 LT |
111 | do_exit(SIGSEGV); |
112 | } | |
decd275e | 113 | set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | vm86->veflags_mask); |
13426356 | 114 | user = vm86->user_vm86; |
ed0b2edb | 115 | |
d4ce0f26 | 116 | if (!access_ok(VERIFY_WRITE, user, vm86->vm86plus.is_vm86pus ? |
ed0b2edb BG |
117 | sizeof(struct vm86plus_struct) : |
118 | sizeof(struct vm86_struct))) { | |
13426356 | 119 | pr_alert("could not access userspace vm86 info\n"); |
ed0b2edb BG |
120 | do_exit(SIGSEGV); |
121 | } | |
122 | ||
123 | put_user_try { | |
124 | put_user_ex(regs->pt.bx, &user->regs.ebx); | |
125 | put_user_ex(regs->pt.cx, &user->regs.ecx); | |
126 | put_user_ex(regs->pt.dx, &user->regs.edx); | |
127 | put_user_ex(regs->pt.si, &user->regs.esi); | |
128 | put_user_ex(regs->pt.di, &user->regs.edi); | |
129 | put_user_ex(regs->pt.bp, &user->regs.ebp); | |
130 | put_user_ex(regs->pt.ax, &user->regs.eax); | |
131 | put_user_ex(regs->pt.ip, &user->regs.eip); | |
132 | put_user_ex(regs->pt.cs, &user->regs.cs); | |
133 | put_user_ex(regs->pt.flags, &user->regs.eflags); | |
134 | put_user_ex(regs->pt.sp, &user->regs.esp); | |
135 | put_user_ex(regs->pt.ss, &user->regs.ss); | |
136 | put_user_ex(regs->es, &user->regs.es); | |
137 | put_user_ex(regs->ds, &user->regs.ds); | |
138 | put_user_ex(regs->fs, &user->regs.fs); | |
139 | put_user_ex(regs->gs, &user->regs.gs); | |
140 | ||
9fda6a06 | 141 | put_user_ex(vm86->screen_bitmap, &user->screen_bitmap); |
ed0b2edb BG |
142 | } put_user_catch(err); |
143 | if (err) { | |
13426356 | 144 | pr_alert("could not access userspace vm86 info\n"); |
1da177e4 LT |
145 | do_exit(SIGSEGV); |
146 | } | |
147 | ||
41f6a89b | 148 | preempt_disable(); |
9fda6a06 | 149 | tsk->thread.sp0 = vm86->saved_sp0; |
ed0b2edb | 150 | tsk->thread.sysenter_cs = __KERNEL_CS; |
cc87284c | 151 | update_sp0(tsk); |
779e32d0 | 152 | refresh_sysenter_cs(&tsk->thread); |
9fda6a06 | 153 | vm86->saved_sp0 = 0; |
41f6a89b | 154 | preempt_enable(); |
1da177e4 | 155 | |
5ed92a8a | 156 | memcpy(®s->pt, &vm86->regs32, sizeof(struct pt_regs)); |
49d26b6e | 157 | |
5ed92a8a | 158 | lazy_load_gs(vm86->regs32.gs); |
49d26b6e | 159 | |
5ed92a8a | 160 | regs->pt.ax = retval; |
1da177e4 LT |
161 | } |
162 | ||
60ec5585 | 163 | static void mark_screen_rdonly(struct mm_struct *mm) |
1da177e4 | 164 | { |
3ba5b5ea KS |
165 | struct vm_area_struct *vma; |
166 | spinlock_t *ptl; | |
1da177e4 | 167 | pgd_t *pgd; |
e0c4f675 | 168 | p4d_t *p4d; |
1da177e4 LT |
169 | pud_t *pud; |
170 | pmd_t *pmd; | |
60ec5585 | 171 | pte_t *pte; |
1da177e4 LT |
172 | int i; |
173 | ||
1a5a9906 | 174 | down_write(&mm->mmap_sem); |
60ec5585 | 175 | pgd = pgd_offset(mm, 0xA0000); |
1da177e4 LT |
176 | if (pgd_none_or_clear_bad(pgd)) |
177 | goto out; | |
e0c4f675 KS |
178 | p4d = p4d_offset(pgd, 0xA0000); |
179 | if (p4d_none_or_clear_bad(p4d)) | |
180 | goto out; | |
181 | pud = pud_offset(p4d, 0xA0000); | |
1da177e4 LT |
182 | if (pud_none_or_clear_bad(pud)) |
183 | goto out; | |
184 | pmd = pmd_offset(pud, 0xA0000); | |
78ddc534 KS |
185 | |
186 | if (pmd_trans_huge(*pmd)) { | |
3ba5b5ea | 187 | vma = find_vma(mm, 0xA0000); |
78ddc534 KS |
188 | split_huge_pmd(vma, pmd, 0xA0000); |
189 | } | |
1da177e4 LT |
190 | if (pmd_none_or_clear_bad(pmd)) |
191 | goto out; | |
60ec5585 | 192 | pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); |
1da177e4 LT |
193 | for (i = 0; i < 32; i++) { |
194 | if (pte_present(*pte)) | |
195 | set_pte(pte, pte_wrprotect(*pte)); | |
196 | pte++; | |
197 | } | |
60ec5585 | 198 | pte_unmap_unlock(pte, ptl); |
1da177e4 | 199 | out: |
1a5a9906 | 200 | up_write(&mm->mmap_sem); |
9ccee237 | 201 | flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, 0UL); |
1da177e4 LT |
202 | } |
203 | ||
204 | ||
205 | ||
206 | static int do_vm86_irq_handling(int subfunction, int irqnumber); | |
13426356 | 207 | static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus); |
1da177e4 | 208 | |
13426356 | 209 | SYSCALL_DEFINE1(vm86old, struct vm86_struct __user *, user_vm86) |
1da177e4 | 210 | { |
13426356 | 211 | return do_sys_vm86((struct vm86plus_struct __user *) user_vm86, false); |
1da177e4 LT |
212 | } |
213 | ||
214 | ||
5522ddb3 | 215 | SYSCALL_DEFINE2(vm86, unsigned long, cmd, unsigned long, arg) |
1da177e4 | 216 | { |
f1382f15 | 217 | switch (cmd) { |
83e714e8 PC |
218 | case VM86_REQUEST_IRQ: |
219 | case VM86_FREE_IRQ: | |
220 | case VM86_GET_IRQ_BITS: | |
221 | case VM86_GET_AND_RESET_IRQ: | |
5522ddb3 | 222 | return do_vm86_irq_handling(cmd, (int)arg); |
83e714e8 PC |
223 | case VM86_PLUS_INSTALL_CHECK: |
224 | /* | |
225 | * NOTE: on old vm86 stuff this will return the error | |
226 | * from access_ok(), because the subfunction is | |
227 | * interpreted as (invalid) address to vm86_struct. | |
228 | * So the installation check works. | |
229 | */ | |
5522ddb3 | 230 | return 0; |
1da177e4 LT |
231 | } |
232 | ||
233 | /* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */ | |
90c6085a | 234 | return do_sys_vm86((struct vm86plus_struct __user *) arg, true); |
1da177e4 LT |
235 | } |
236 | ||
237 | ||
13426356 | 238 | static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus) |
1da177e4 | 239 | { |
ed0b2edb | 240 | struct task_struct *tsk = current; |
9fda6a06 | 241 | struct vm86 *vm86 = tsk->thread.vm86; |
90c6085a | 242 | struct kernel_vm86_regs vm86regs; |
5ed92a8a | 243 | struct pt_regs *regs = current_pt_regs(); |
ed0b2edb BG |
244 | unsigned long err = 0; |
245 | ||
76fc5e7b AL |
246 | err = security_mmap_addr(0); |
247 | if (err) { | |
248 | /* | |
249 | * vm86 cannot virtualize the address space, so vm86 users | |
250 | * need to manage the low 1MB themselves using mmap. Given | |
251 | * that BIOS places important data in the first page, vm86 | |
252 | * is essentially useless if mmap_min_addr != 0. DOSEMU, | |
253 | * for example, won't even bother trying to use vm86 if it | |
254 | * can't map a page at virtual address 0. | |
255 | * | |
256 | * To reduce the available kernel attack surface, simply | |
257 | * disallow vm86(old) for users who cannot mmap at va 0. | |
258 | * | |
259 | * The implementation of security_mmap_addr will allow | |
260 | * suitably privileged users to map va 0 even if | |
261 | * vm.mmap_min_addr is set above 0, and we want this | |
262 | * behavior for vm86 as well, as it ensures that legacy | |
263 | * tools like vbetool will not fail just because of | |
264 | * vm.mmap_min_addr. | |
265 | */ | |
266 | pr_info_once("Denied a call to vm86(old) from %s[%d] (uid: %d). Set the vm.mmap_min_addr sysctl to 0 and/or adjust LSM mmap_min_addr policy to enable vm86 if you are using a vm86-based DOS emulator.\n", | |
267 | current->comm, task_pid_nr(current), | |
268 | from_kuid_munged(&init_user_ns, current_uid())); | |
269 | return -EPERM; | |
270 | } | |
271 | ||
9fda6a06 BG |
272 | if (!vm86) { |
273 | if (!(vm86 = kzalloc(sizeof(*vm86), GFP_KERNEL))) | |
274 | return -ENOMEM; | |
275 | tsk->thread.vm86 = vm86; | |
276 | } | |
277 | if (vm86->saved_sp0) | |
ed0b2edb BG |
278 | return -EPERM; |
279 | ||
13426356 | 280 | if (!access_ok(VERIFY_READ, user_vm86, plus ? |
ed0b2edb BG |
281 | sizeof(struct vm86_struct) : |
282 | sizeof(struct vm86plus_struct))) | |
283 | return -EFAULT; | |
284 | ||
90c6085a | 285 | memset(&vm86regs, 0, sizeof(vm86regs)); |
ed0b2edb BG |
286 | get_user_try { |
287 | unsigned short seg; | |
13426356 BG |
288 | get_user_ex(vm86regs.pt.bx, &user_vm86->regs.ebx); |
289 | get_user_ex(vm86regs.pt.cx, &user_vm86->regs.ecx); | |
290 | get_user_ex(vm86regs.pt.dx, &user_vm86->regs.edx); | |
291 | get_user_ex(vm86regs.pt.si, &user_vm86->regs.esi); | |
292 | get_user_ex(vm86regs.pt.di, &user_vm86->regs.edi); | |
293 | get_user_ex(vm86regs.pt.bp, &user_vm86->regs.ebp); | |
294 | get_user_ex(vm86regs.pt.ax, &user_vm86->regs.eax); | |
295 | get_user_ex(vm86regs.pt.ip, &user_vm86->regs.eip); | |
296 | get_user_ex(seg, &user_vm86->regs.cs); | |
90c6085a | 297 | vm86regs.pt.cs = seg; |
13426356 BG |
298 | get_user_ex(vm86regs.pt.flags, &user_vm86->regs.eflags); |
299 | get_user_ex(vm86regs.pt.sp, &user_vm86->regs.esp); | |
300 | get_user_ex(seg, &user_vm86->regs.ss); | |
90c6085a | 301 | vm86regs.pt.ss = seg; |
13426356 BG |
302 | get_user_ex(vm86regs.es, &user_vm86->regs.es); |
303 | get_user_ex(vm86regs.ds, &user_vm86->regs.ds); | |
304 | get_user_ex(vm86regs.fs, &user_vm86->regs.fs); | |
305 | get_user_ex(vm86regs.gs, &user_vm86->regs.gs); | |
306 | ||
307 | get_user_ex(vm86->flags, &user_vm86->flags); | |
308 | get_user_ex(vm86->screen_bitmap, &user_vm86->screen_bitmap); | |
309 | get_user_ex(vm86->cpu_type, &user_vm86->cpu_type); | |
ed0b2edb BG |
310 | } get_user_catch(err); |
311 | if (err) | |
312 | return err; | |
313 | ||
13426356 BG |
314 | if (copy_from_user(&vm86->int_revectored, |
315 | &user_vm86->int_revectored, | |
ed0b2edb BG |
316 | sizeof(struct revectored_struct))) |
317 | return -EFAULT; | |
13426356 BG |
318 | if (copy_from_user(&vm86->int21_revectored, |
319 | &user_vm86->int21_revectored, | |
ed0b2edb BG |
320 | sizeof(struct revectored_struct))) |
321 | return -EFAULT; | |
322 | if (plus) { | |
13426356 | 323 | if (copy_from_user(&vm86->vm86plus, &user_vm86->vm86plus, |
ed0b2edb BG |
324 | sizeof(struct vm86plus_info_struct))) |
325 | return -EFAULT; | |
d4ce0f26 BG |
326 | vm86->vm86plus.is_vm86pus = 1; |
327 | } else | |
328 | memset(&vm86->vm86plus, 0, | |
329 | sizeof(struct vm86plus_info_struct)); | |
5ed92a8a BG |
330 | |
331 | memcpy(&vm86->regs32, regs, sizeof(struct pt_regs)); | |
13426356 | 332 | vm86->user_vm86 = user_vm86; |
1da177e4 LT |
333 | |
334 | /* | |
65ea5b03 | 335 | * The flags register is also special: we cannot trust that the user |
1da177e4 LT |
336 | * has set it up safely, so this makes sure interrupt etc flags are |
337 | * inherited from protected mode. | |
338 | */ | |
90c6085a BG |
339 | VEFLAGS = vm86regs.pt.flags; |
340 | vm86regs.pt.flags &= SAFE_MASK; | |
5ed92a8a | 341 | vm86regs.pt.flags |= regs->flags & ~SAFE_MASK; |
90c6085a | 342 | vm86regs.pt.flags |= X86_VM_MASK; |
1da177e4 | 343 | |
5ed92a8a | 344 | vm86regs.pt.orig_ax = regs->orig_ax; |
df1ae9a5 | 345 | |
d4ce0f26 | 346 | switch (vm86->cpu_type) { |
83e714e8 | 347 | case CPU_286: |
decd275e | 348 | vm86->veflags_mask = 0; |
83e714e8 PC |
349 | break; |
350 | case CPU_386: | |
decd275e | 351 | vm86->veflags_mask = X86_EFLAGS_NT | X86_EFLAGS_IOPL; |
83e714e8 PC |
352 | break; |
353 | case CPU_486: | |
decd275e | 354 | vm86->veflags_mask = X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL; |
83e714e8 PC |
355 | break; |
356 | default: | |
decd275e | 357 | vm86->veflags_mask = X86_EFLAGS_ID | X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL; |
83e714e8 | 358 | break; |
1da177e4 LT |
359 | } |
360 | ||
361 | /* | |
5ed92a8a | 362 | * Save old state |
1da177e4 | 363 | */ |
9fda6a06 | 364 | vm86->saved_sp0 = tsk->thread.sp0; |
5ed92a8a | 365 | lazy_save_gs(vm86->regs32.gs); |
1da177e4 | 366 | |
5ed92a8a | 367 | /* make room for real-mode segments */ |
41f6a89b | 368 | preempt_disable(); |
5ed92a8a | 369 | tsk->thread.sp0 += 16; |
362f924b | 370 | |
779e32d0 | 371 | if (static_cpu_has(X86_FEATURE_SEP)) { |
1da177e4 | 372 | tsk->thread.sysenter_cs = 0; |
779e32d0 AL |
373 | refresh_sysenter_cs(&tsk->thread); |
374 | } | |
362f924b | 375 | |
cc87284c | 376 | update_sp0(tsk); |
41f6a89b | 377 | preempt_enable(); |
1da177e4 | 378 | |
d4ce0f26 | 379 | if (vm86->flags & VM86_SCREEN_BITMAP) |
60ec5585 | 380 | mark_screen_rdonly(tsk->mm); |
7e7f8a03 | 381 | |
5ed92a8a BG |
382 | memcpy((struct kernel_vm86_regs *)regs, &vm86regs, sizeof(vm86regs)); |
383 | force_iret(); | |
384 | return regs->ax; | |
1da177e4 LT |
385 | } |
386 | ||
83e714e8 | 387 | static inline void set_IF(struct kernel_vm86_regs *regs) |
1da177e4 | 388 | { |
a5c15d41 | 389 | VEFLAGS |= X86_EFLAGS_VIF; |
1da177e4 LT |
390 | } |
391 | ||
83e714e8 | 392 | static inline void clear_IF(struct kernel_vm86_regs *regs) |
1da177e4 | 393 | { |
a5c15d41 | 394 | VEFLAGS &= ~X86_EFLAGS_VIF; |
1da177e4 LT |
395 | } |
396 | ||
83e714e8 | 397 | static inline void clear_TF(struct kernel_vm86_regs *regs) |
1da177e4 | 398 | { |
a5c15d41 | 399 | regs->pt.flags &= ~X86_EFLAGS_TF; |
1da177e4 LT |
400 | } |
401 | ||
83e714e8 | 402 | static inline void clear_AC(struct kernel_vm86_regs *regs) |
1da177e4 | 403 | { |
a5c15d41 | 404 | regs->pt.flags &= ~X86_EFLAGS_AC; |
1da177e4 LT |
405 | } |
406 | ||
83e714e8 PC |
407 | /* |
408 | * It is correct to call set_IF(regs) from the set_vflags_* | |
1da177e4 LT |
409 | * functions. However someone forgot to call clear_IF(regs) |
410 | * in the opposite case. | |
411 | * After the command sequence CLI PUSHF STI POPF you should | |
ab4a574e | 412 | * end up with interrupts disabled, but you ended up with |
1da177e4 LT |
413 | * interrupts enabled. |
414 | * ( I was testing my own changes, but the only bug I | |
415 | * could find was in a function I had not changed. ) | |
416 | * [KD] | |
417 | */ | |
418 | ||
83e714e8 | 419 | static inline void set_vflags_long(unsigned long flags, struct kernel_vm86_regs *regs) |
1da177e4 | 420 | { |
decd275e | 421 | set_flags(VEFLAGS, flags, current->thread.vm86->veflags_mask); |
65ea5b03 | 422 | set_flags(regs->pt.flags, flags, SAFE_MASK); |
a5c15d41 | 423 | if (flags & X86_EFLAGS_IF) |
1da177e4 LT |
424 | set_IF(regs); |
425 | else | |
426 | clear_IF(regs); | |
427 | } | |
428 | ||
83e714e8 | 429 | static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs *regs) |
1da177e4 | 430 | { |
decd275e | 431 | set_flags(VFLAGS, flags, current->thread.vm86->veflags_mask); |
65ea5b03 | 432 | set_flags(regs->pt.flags, flags, SAFE_MASK); |
a5c15d41 | 433 | if (flags & X86_EFLAGS_IF) |
1da177e4 LT |
434 | set_IF(regs); |
435 | else | |
436 | clear_IF(regs); | |
437 | } | |
438 | ||
83e714e8 | 439 | static inline unsigned long get_vflags(struct kernel_vm86_regs *regs) |
1da177e4 | 440 | { |
65ea5b03 | 441 | unsigned long flags = regs->pt.flags & RETURN_MASK; |
1da177e4 | 442 | |
a5c15d41 | 443 | if (VEFLAGS & X86_EFLAGS_VIF) |
444 | flags |= X86_EFLAGS_IF; | |
445 | flags |= X86_EFLAGS_IOPL; | |
decd275e | 446 | return flags | (VEFLAGS & current->thread.vm86->veflags_mask); |
1da177e4 LT |
447 | } |
448 | ||
83e714e8 | 449 | static inline int is_revectored(int nr, struct revectored_struct *bitmap) |
1da177e4 | 450 | { |
2823d4da | 451 | return test_bit(nr, bitmap->__map); |
1da177e4 LT |
452 | } |
453 | ||
454 | #define val_byte(val, n) (((__u8 *)&val)[n]) | |
455 | ||
456 | #define pushb(base, ptr, val, err_label) \ | |
457 | do { \ | |
458 | __u8 __val = val; \ | |
459 | ptr--; \ | |
460 | if (put_user(__val, base + ptr) < 0) \ | |
461 | goto err_label; \ | |
83e714e8 | 462 | } while (0) |
1da177e4 LT |
463 | |
464 | #define pushw(base, ptr, val, err_label) \ | |
465 | do { \ | |
466 | __u16 __val = val; \ | |
467 | ptr--; \ | |
468 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
469 | goto err_label; \ | |
470 | ptr--; \ | |
471 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
472 | goto err_label; \ | |
83e714e8 | 473 | } while (0) |
1da177e4 LT |
474 | |
475 | #define pushl(base, ptr, val, err_label) \ | |
476 | do { \ | |
477 | __u32 __val = val; \ | |
478 | ptr--; \ | |
479 | if (put_user(val_byte(__val, 3), base + ptr) < 0) \ | |
480 | goto err_label; \ | |
481 | ptr--; \ | |
482 | if (put_user(val_byte(__val, 2), base + ptr) < 0) \ | |
483 | goto err_label; \ | |
484 | ptr--; \ | |
485 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
486 | goto err_label; \ | |
487 | ptr--; \ | |
488 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
489 | goto err_label; \ | |
83e714e8 | 490 | } while (0) |
1da177e4 LT |
491 | |
492 | #define popb(base, ptr, err_label) \ | |
493 | ({ \ | |
494 | __u8 __res; \ | |
495 | if (get_user(__res, base + ptr) < 0) \ | |
496 | goto err_label; \ | |
497 | ptr++; \ | |
498 | __res; \ | |
499 | }) | |
500 | ||
501 | #define popw(base, ptr, err_label) \ | |
502 | ({ \ | |
503 | __u16 __res; \ | |
504 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
505 | goto err_label; \ | |
506 | ptr++; \ | |
507 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
508 | goto err_label; \ | |
509 | ptr++; \ | |
510 | __res; \ | |
511 | }) | |
512 | ||
513 | #define popl(base, ptr, err_label) \ | |
514 | ({ \ | |
515 | __u32 __res; \ | |
516 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
517 | goto err_label; \ | |
518 | ptr++; \ | |
519 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
520 | goto err_label; \ | |
521 | ptr++; \ | |
522 | if (get_user(val_byte(__res, 2), base + ptr) < 0) \ | |
523 | goto err_label; \ | |
524 | ptr++; \ | |
525 | if (get_user(val_byte(__res, 3), base + ptr) < 0) \ | |
526 | goto err_label; \ | |
527 | ptr++; \ | |
528 | __res; \ | |
529 | }) | |
530 | ||
531 | /* There are so many possible reasons for this function to return | |
532 | * VM86_INTx, so adding another doesn't bother me. We can expect | |
533 | * userspace programs to be able to handle it. (Getting a problem | |
534 | * in userspace is always better than an Oops anyway.) [KD] | |
535 | */ | |
536 | static void do_int(struct kernel_vm86_regs *regs, int i, | |
83e714e8 | 537 | unsigned char __user *ssp, unsigned short sp) |
1da177e4 LT |
538 | { |
539 | unsigned long __user *intr_ptr; | |
540 | unsigned long segoffs; | |
90c6085a | 541 | struct vm86 *vm86 = current->thread.vm86; |
1da177e4 | 542 | |
65ea5b03 | 543 | if (regs->pt.cs == BIOSSEG) |
1da177e4 | 544 | goto cannot_handle; |
d4ce0f26 | 545 | if (is_revectored(i, &vm86->int_revectored)) |
1da177e4 | 546 | goto cannot_handle; |
d4ce0f26 | 547 | if (i == 0x21 && is_revectored(AH(regs), &vm86->int21_revectored)) |
1da177e4 LT |
548 | goto cannot_handle; |
549 | intr_ptr = (unsigned long __user *) (i << 2); | |
550 | if (get_user(segoffs, intr_ptr)) | |
551 | goto cannot_handle; | |
552 | if ((segoffs >> 16) == BIOSSEG) | |
553 | goto cannot_handle; | |
554 | pushw(ssp, sp, get_vflags(regs), cannot_handle); | |
65ea5b03 | 555 | pushw(ssp, sp, regs->pt.cs, cannot_handle); |
1da177e4 | 556 | pushw(ssp, sp, IP(regs), cannot_handle); |
65ea5b03 | 557 | regs->pt.cs = segoffs >> 16; |
1da177e4 LT |
558 | SP(regs) -= 6; |
559 | IP(regs) = segoffs & 0xffff; | |
560 | clear_TF(regs); | |
561 | clear_IF(regs); | |
562 | clear_AC(regs); | |
563 | return; | |
564 | ||
565 | cannot_handle: | |
5ed92a8a | 566 | save_v86_state(regs, VM86_INTx + (i << 8)); |
1da177e4 LT |
567 | } |
568 | ||
83e714e8 | 569 | int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno) |
1da177e4 | 570 | { |
90c6085a BG |
571 | struct vm86 *vm86 = current->thread.vm86; |
572 | ||
573 | if (vm86->vm86plus.is_vm86pus) { | |
6554287b | 574 | if ((trapno == 3) || (trapno == 1)) { |
5ed92a8a | 575 | save_v86_state(regs, VM86_TRAP + (trapno << 8)); |
6554287b BO |
576 | return 0; |
577 | } | |
65ea5b03 | 578 | do_int(regs, trapno, (unsigned char __user *) (regs->pt.ss << 4), SP(regs)); |
1da177e4 LT |
579 | return 0; |
580 | } | |
83e714e8 | 581 | if (trapno != 1) |
1da177e4 | 582 | return 1; /* we let this handle by the calling routine */ |
51e7dc70 | 583 | current->thread.trap_nr = trapno; |
1da177e4 | 584 | current->thread.error_code = error_code; |
0f540910 | 585 | force_sig(SIGTRAP, current); |
1da177e4 LT |
586 | return 0; |
587 | } | |
588 | ||
83e714e8 | 589 | void handle_vm86_fault(struct kernel_vm86_regs *regs, long error_code) |
1da177e4 LT |
590 | { |
591 | unsigned char opcode; | |
592 | unsigned char __user *csp; | |
593 | unsigned char __user *ssp; | |
5fd75ebb | 594 | unsigned short ip, sp, orig_flags; |
1da177e4 | 595 | int data32, pref_done; |
d4ce0f26 | 596 | struct vm86plus_info_struct *vmpi = ¤t->thread.vm86->vm86plus; |
1da177e4 LT |
597 | |
598 | #define CHECK_IF_IN_TRAP \ | |
d4ce0f26 | 599 | if (vmpi->vm86dbg_active && vmpi->vm86dbg_TFpendig) \ |
a5c15d41 | 600 | newflags |= X86_EFLAGS_TF |
1da177e4 | 601 | |
65ea5b03 | 602 | orig_flags = *(unsigned short *)®s->pt.flags; |
5fd75ebb | 603 | |
65ea5b03 PA |
604 | csp = (unsigned char __user *) (regs->pt.cs << 4); |
605 | ssp = (unsigned char __user *) (regs->pt.ss << 4); | |
1da177e4 LT |
606 | sp = SP(regs); |
607 | ip = IP(regs); | |
608 | ||
609 | data32 = 0; | |
610 | pref_done = 0; | |
611 | do { | |
612 | switch (opcode = popb(csp, ip, simulate_sigsegv)) { | |
83e714e8 PC |
613 | case 0x66: /* 32-bit data */ data32 = 1; break; |
614 | case 0x67: /* 32-bit address */ break; | |
615 | case 0x2e: /* CS */ break; | |
616 | case 0x3e: /* DS */ break; | |
617 | case 0x26: /* ES */ break; | |
618 | case 0x36: /* SS */ break; | |
619 | case 0x65: /* GS */ break; | |
620 | case 0x64: /* FS */ break; | |
621 | case 0xf2: /* repnz */ break; | |
622 | case 0xf3: /* rep */ break; | |
623 | default: pref_done = 1; | |
1da177e4 LT |
624 | } |
625 | } while (!pref_done); | |
626 | ||
627 | switch (opcode) { | |
628 | ||
629 | /* pushf */ | |
630 | case 0x9c: | |
631 | if (data32) { | |
632 | pushl(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
633 | SP(regs) -= 4; | |
634 | } else { | |
635 | pushw(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
636 | SP(regs) -= 2; | |
637 | } | |
638 | IP(regs) = ip; | |
5ed92a8a | 639 | goto vm86_fault_return; |
1da177e4 LT |
640 | |
641 | /* popf */ | |
642 | case 0x9d: | |
643 | { | |
644 | unsigned long newflags; | |
645 | if (data32) { | |
83e714e8 | 646 | newflags = popl(ssp, sp, simulate_sigsegv); |
1da177e4 LT |
647 | SP(regs) += 4; |
648 | } else { | |
649 | newflags = popw(ssp, sp, simulate_sigsegv); | |
650 | SP(regs) += 2; | |
651 | } | |
652 | IP(regs) = ip; | |
653 | CHECK_IF_IN_TRAP; | |
83e714e8 | 654 | if (data32) |
1da177e4 | 655 | set_vflags_long(newflags, regs); |
83e714e8 | 656 | else |
1da177e4 | 657 | set_vflags_short(newflags, regs); |
83e714e8 | 658 | |
5ed92a8a | 659 | goto check_vip; |
1da177e4 LT |
660 | } |
661 | ||
662 | /* int xx */ | |
663 | case 0xcd: { | |
83e714e8 | 664 | int intno = popb(csp, ip, simulate_sigsegv); |
1da177e4 | 665 | IP(regs) = ip; |
d4ce0f26 | 666 | if (vmpi->vm86dbg_active) { |
5ed92a8a BG |
667 | if ((1 << (intno & 7)) & vmpi->vm86dbg_intxxtab[intno >> 3]) { |
668 | save_v86_state(regs, VM86_INTx + (intno << 8)); | |
669 | return; | |
670 | } | |
1da177e4 LT |
671 | } |
672 | do_int(regs, intno, ssp, sp); | |
673 | return; | |
674 | } | |
675 | ||
676 | /* iret */ | |
677 | case 0xcf: | |
678 | { | |
679 | unsigned long newip; | |
680 | unsigned long newcs; | |
681 | unsigned long newflags; | |
682 | if (data32) { | |
83e714e8 PC |
683 | newip = popl(ssp, sp, simulate_sigsegv); |
684 | newcs = popl(ssp, sp, simulate_sigsegv); | |
685 | newflags = popl(ssp, sp, simulate_sigsegv); | |
1da177e4 LT |
686 | SP(regs) += 12; |
687 | } else { | |
688 | newip = popw(ssp, sp, simulate_sigsegv); | |
689 | newcs = popw(ssp, sp, simulate_sigsegv); | |
690 | newflags = popw(ssp, sp, simulate_sigsegv); | |
691 | SP(regs) += 6; | |
692 | } | |
693 | IP(regs) = newip; | |
65ea5b03 | 694 | regs->pt.cs = newcs; |
1da177e4 LT |
695 | CHECK_IF_IN_TRAP; |
696 | if (data32) { | |
697 | set_vflags_long(newflags, regs); | |
698 | } else { | |
699 | set_vflags_short(newflags, regs); | |
700 | } | |
5ed92a8a | 701 | goto check_vip; |
1da177e4 LT |
702 | } |
703 | ||
704 | /* cli */ | |
705 | case 0xfa: | |
706 | IP(regs) = ip; | |
707 | clear_IF(regs); | |
5ed92a8a | 708 | goto vm86_fault_return; |
1da177e4 LT |
709 | |
710 | /* sti */ | |
711 | /* | |
712 | * Damn. This is incorrect: the 'sti' instruction should actually | |
713 | * enable interrupts after the /next/ instruction. Not good. | |
714 | * | |
715 | * Probably needs some horsing around with the TF flag. Aiee.. | |
716 | */ | |
717 | case 0xfb: | |
718 | IP(regs) = ip; | |
719 | set_IF(regs); | |
5ed92a8a | 720 | goto check_vip; |
1da177e4 LT |
721 | |
722 | default: | |
5ed92a8a | 723 | save_v86_state(regs, VM86_UNKNOWN); |
1da177e4 LT |
724 | } |
725 | ||
726 | return; | |
727 | ||
5ed92a8a BG |
728 | check_vip: |
729 | if (VEFLAGS & X86_EFLAGS_VIP) { | |
730 | save_v86_state(regs, VM86_STI); | |
731 | return; | |
732 | } | |
733 | ||
734 | vm86_fault_return: | |
735 | if (vmpi->force_return_for_pic && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) { | |
736 | save_v86_state(regs, VM86_PICRETURN); | |
737 | return; | |
738 | } | |
739 | if (orig_flags & X86_EFLAGS_TF) | |
740 | handle_vm86_trap(regs, 0, X86_TRAP_DB); | |
741 | return; | |
742 | ||
1da177e4 LT |
743 | simulate_sigsegv: |
744 | /* FIXME: After a long discussion with Stas we finally | |
745 | * agreed, that this is wrong. Here we should | |
746 | * really send a SIGSEGV to the user program. | |
747 | * But how do we create the correct context? We | |
748 | * are inside a general protection fault handler | |
749 | * and has just returned from a page fault handler. | |
750 | * The correct context for the signal handler | |
751 | * should be a mixture of the two, but how do we | |
752 | * get the information? [KD] | |
753 | */ | |
5ed92a8a | 754 | save_v86_state(regs, VM86_UNKNOWN); |
1da177e4 LT |
755 | } |
756 | ||
757 | /* ---------------- vm86 special IRQ passing stuff ----------------- */ | |
758 | ||
759 | #define VM86_IRQNAME "vm86irq" | |
760 | ||
761 | static struct vm86_irqs { | |
762 | struct task_struct *tsk; | |
763 | int sig; | |
764 | } vm86_irqs[16]; | |
765 | ||
766 | static DEFINE_SPINLOCK(irqbits_lock); | |
767 | static int irqbits; | |
768 | ||
83e714e8 | 769 | #define ALLOWED_SIGS (1 /* 0 = don't send a signal */ \ |
1da177e4 | 770 | | (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO) | (1 << SIGURG) \ |
83e714e8 PC |
771 | | (1 << SIGUNUSED)) |
772 | ||
7d12e780 | 773 | static irqreturn_t irq_handler(int intno, void *dev_id) |
1da177e4 LT |
774 | { |
775 | int irq_bit; | |
776 | unsigned long flags; | |
777 | ||
83e714e8 | 778 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 | 779 | irq_bit = 1 << intno; |
83e714e8 | 780 | if ((irqbits & irq_bit) || !vm86_irqs[intno].tsk) |
1da177e4 LT |
781 | goto out; |
782 | irqbits |= irq_bit; | |
783 | if (vm86_irqs[intno].sig) | |
784 | send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1); | |
1da177e4 LT |
785 | /* |
786 | * IRQ will be re-enabled when user asks for the irq (whether | |
787 | * polling or as a result of the signal) | |
788 | */ | |
ad671423 PP |
789 | disable_irq_nosync(intno); |
790 | spin_unlock_irqrestore(&irqbits_lock, flags); | |
1da177e4 LT |
791 | return IRQ_HANDLED; |
792 | ||
793 | out: | |
83e714e8 | 794 | spin_unlock_irqrestore(&irqbits_lock, flags); |
1da177e4 LT |
795 | return IRQ_NONE; |
796 | } | |
797 | ||
798 | static inline void free_vm86_irq(int irqnumber) | |
799 | { | |
800 | unsigned long flags; | |
801 | ||
802 | free_irq(irqnumber, NULL); | |
803 | vm86_irqs[irqnumber].tsk = NULL; | |
804 | ||
83e714e8 | 805 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 | 806 | irqbits &= ~(1 << irqnumber); |
83e714e8 | 807 | spin_unlock_irqrestore(&irqbits_lock, flags); |
1da177e4 LT |
808 | } |
809 | ||
810 | void release_vm86_irqs(struct task_struct *task) | |
811 | { | |
812 | int i; | |
813 | for (i = FIRST_VM86_IRQ ; i <= LAST_VM86_IRQ; i++) | |
814 | if (vm86_irqs[i].tsk == task) | |
815 | free_vm86_irq(i); | |
816 | } | |
817 | ||
818 | static inline int get_and_reset_irq(int irqnumber) | |
819 | { | |
820 | int bit; | |
821 | unsigned long flags; | |
ad671423 | 822 | int ret = 0; |
83e714e8 | 823 | |
1da177e4 LT |
824 | if (invalid_vm86_irq(irqnumber)) return 0; |
825 | if (vm86_irqs[irqnumber].tsk != current) return 0; | |
83e714e8 | 826 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 LT |
827 | bit = irqbits & (1 << irqnumber); |
828 | irqbits &= ~bit; | |
ad671423 PP |
829 | if (bit) { |
830 | enable_irq(irqnumber); | |
831 | ret = 1; | |
832 | } | |
833 | ||
83e714e8 | 834 | spin_unlock_irqrestore(&irqbits_lock, flags); |
ad671423 | 835 | return ret; |
1da177e4 LT |
836 | } |
837 | ||
838 | ||
839 | static int do_vm86_irq_handling(int subfunction, int irqnumber) | |
840 | { | |
841 | int ret; | |
842 | switch (subfunction) { | |
843 | case VM86_GET_AND_RESET_IRQ: { | |
844 | return get_and_reset_irq(irqnumber); | |
845 | } | |
846 | case VM86_GET_IRQ_BITS: { | |
847 | return irqbits; | |
848 | } | |
849 | case VM86_REQUEST_IRQ: { | |
850 | int sig = irqnumber >> 8; | |
851 | int irq = irqnumber & 255; | |
852 | if (!capable(CAP_SYS_ADMIN)) return -EPERM; | |
853 | if (!((1 << sig) & ALLOWED_SIGS)) return -EPERM; | |
854 | if (invalid_vm86_irq(irq)) return -EPERM; | |
855 | if (vm86_irqs[irq].tsk) return -EPERM; | |
856 | ret = request_irq(irq, &irq_handler, 0, VM86_IRQNAME, NULL); | |
857 | if (ret) return ret; | |
858 | vm86_irqs[irq].sig = sig; | |
859 | vm86_irqs[irq].tsk = current; | |
860 | return irq; | |
861 | } | |
862 | case VM86_FREE_IRQ: { | |
863 | if (invalid_vm86_irq(irqnumber)) return -EPERM; | |
864 | if (!vm86_irqs[irqnumber].tsk) return 0; | |
865 | if (vm86_irqs[irqnumber].tsk != current) return -EPERM; | |
866 | free_vm86_irq(irqnumber); | |
867 | return 0; | |
868 | } | |
869 | } | |
870 | return -EINVAL; | |
871 | } | |
872 |