Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
1da177e4 LT |
3 | * Copyright (C) 1994 Linus Torvalds |
4 | * | |
5 | * 29 dec 2001 - Fixed oopses caused by unchecked access to the vm86 | |
624dffcb | 6 | * stack - Manfred Spraul <manfred@colorfullife.com> |
1da177e4 LT |
7 | * |
8 | * 22 mar 2002 - Manfred detected the stackfaults, but didn't handle | |
9 | * them correctly. Now the emulation will be in a | |
10 | * consistent state after stackfaults - Kasper Dupont | |
11 | * <kasperd@daimi.au.dk> | |
12 | * | |
13 | * 22 mar 2002 - Added missing clear_IF in set_vflags_* Kasper Dupont | |
14 | * <kasperd@daimi.au.dk> | |
15 | * | |
16 | * ?? ??? 2002 - Fixed premature returns from handle_vm86_fault | |
17 | * caused by Kasper Dupont's changes - Stas Sergeev | |
18 | * | |
19 | * 4 apr 2002 - Fixed CHECK_IF_IN_TRAP broken by Stas' changes. | |
20 | * Kasper Dupont <kasperd@daimi.au.dk> | |
21 | * | |
22 | * 9 apr 2002 - Changed syntax of macros in handle_vm86_fault. | |
23 | * Kasper Dupont <kasperd@daimi.au.dk> | |
24 | * | |
25 | * 9 apr 2002 - Changed stack access macros to jump to a label | |
26 | * instead of returning to userspace. This simplifies | |
27 | * do_int, and is needed by handle_vm6_fault. Kasper | |
28 | * Dupont <kasperd@daimi.au.dk> | |
29 | * | |
30 | */ | |
31 | ||
c767a54b JP |
32 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
33 | ||
a9415644 | 34 | #include <linux/capability.h> |
1da177e4 LT |
35 | #include <linux/errno.h> |
36 | #include <linux/interrupt.h> | |
5522ddb3 | 37 | #include <linux/syscalls.h> |
1da177e4 | 38 | #include <linux/sched.h> |
68db0cf1 | 39 | #include <linux/sched/task_stack.h> |
1da177e4 LT |
40 | #include <linux/kernel.h> |
41 | #include <linux/signal.h> | |
42 | #include <linux/string.h> | |
43 | #include <linux/mm.h> | |
44 | #include <linux/smp.h> | |
1da177e4 LT |
45 | #include <linux/highmem.h> |
46 | #include <linux/ptrace.h> | |
7e7f8a03 | 47 | #include <linux/audit.h> |
49d26b6e | 48 | #include <linux/stddef.h> |
9fda6a06 | 49 | #include <linux/slab.h> |
76fc5e7b | 50 | #include <linux/security.h> |
1da177e4 | 51 | |
7c0f6ba6 | 52 | #include <linux/uaccess.h> |
1da177e4 LT |
53 | #include <asm/io.h> |
54 | #include <asm/tlbflush.h> | |
55 | #include <asm/irq.h> | |
5ed92a8a | 56 | #include <asm/traps.h> |
ba3e127e | 57 | #include <asm/vm86.h> |
bd7dc5a6 | 58 | #include <asm/switch_to.h> |
1da177e4 LT |
59 | |
60 | /* | |
61 | * Known problems: | |
62 | * | |
63 | * Interrupt handling is not guaranteed: | |
64 | * - a real x86 will disable all interrupts for one instruction | |
65 | * after a "mov ss,xx" to make stack handling atomic even without | |
66 | * the 'lss' instruction. We can't guarantee this in v86 mode, | |
67 | * as the next instruction might result in a page fault or similar. | |
68 | * - a real x86 will have interrupts disabled for one instruction | |
69 | * past the 'sti' that enables them. We don't bother with all the | |
70 | * details yet. | |
71 | * | |
72 | * Let's hope these problems do not actually matter for anything. | |
73 | */ | |
74 | ||
75 | ||
1da177e4 LT |
76 | /* |
77 | * 8- and 16-bit register defines.. | |
78 | */ | |
65ea5b03 PA |
79 | #define AL(regs) (((unsigned char *)&((regs)->pt.ax))[0]) |
80 | #define AH(regs) (((unsigned char *)&((regs)->pt.ax))[1]) | |
81 | #define IP(regs) (*(unsigned short *)&((regs)->pt.ip)) | |
82 | #define SP(regs) (*(unsigned short *)&((regs)->pt.sp)) | |
1da177e4 LT |
83 | |
84 | /* | |
85 | * virtual flags (16 and 32-bit versions) | |
86 | */ | |
decd275e BG |
87 | #define VFLAGS (*(unsigned short *)&(current->thread.vm86->veflags)) |
88 | #define VEFLAGS (current->thread.vm86->veflags) | |
1da177e4 | 89 | |
83e714e8 | 90 | #define set_flags(X, new, mask) \ |
1da177e4 LT |
91 | ((X) = ((X) & ~(mask)) | ((new) & (mask))) |
92 | ||
93 | #define SAFE_MASK (0xDD5) | |
94 | #define RETURN_MASK (0xDFF) | |
95 | ||
5ed92a8a | 96 | void save_v86_state(struct kernel_vm86_regs *regs, int retval) |
1da177e4 | 97 | { |
ed0b2edb BG |
98 | struct task_struct *tsk = current; |
99 | struct vm86plus_struct __user *user; | |
9fda6a06 | 100 | struct vm86 *vm86 = current->thread.vm86; |
ed0b2edb | 101 | long err = 0; |
1da177e4 LT |
102 | |
103 | /* | |
104 | * This gets called from entry.S with interrupts disabled, but | |
105 | * from process context. Enable interrupts here, before trying | |
106 | * to access user space. | |
107 | */ | |
108 | local_irq_enable(); | |
109 | ||
13426356 BG |
110 | if (!vm86 || !vm86->user_vm86) { |
111 | pr_alert("no user_vm86: BAD\n"); | |
1da177e4 LT |
112 | do_exit(SIGSEGV); |
113 | } | |
decd275e | 114 | set_flags(regs->pt.flags, VEFLAGS, X86_EFLAGS_VIF | vm86->veflags_mask); |
13426356 | 115 | user = vm86->user_vm86; |
ed0b2edb | 116 | |
d4ce0f26 | 117 | if (!access_ok(VERIFY_WRITE, user, vm86->vm86plus.is_vm86pus ? |
ed0b2edb BG |
118 | sizeof(struct vm86plus_struct) : |
119 | sizeof(struct vm86_struct))) { | |
13426356 | 120 | pr_alert("could not access userspace vm86 info\n"); |
ed0b2edb BG |
121 | do_exit(SIGSEGV); |
122 | } | |
123 | ||
124 | put_user_try { | |
125 | put_user_ex(regs->pt.bx, &user->regs.ebx); | |
126 | put_user_ex(regs->pt.cx, &user->regs.ecx); | |
127 | put_user_ex(regs->pt.dx, &user->regs.edx); | |
128 | put_user_ex(regs->pt.si, &user->regs.esi); | |
129 | put_user_ex(regs->pt.di, &user->regs.edi); | |
130 | put_user_ex(regs->pt.bp, &user->regs.ebp); | |
131 | put_user_ex(regs->pt.ax, &user->regs.eax); | |
132 | put_user_ex(regs->pt.ip, &user->regs.eip); | |
133 | put_user_ex(regs->pt.cs, &user->regs.cs); | |
134 | put_user_ex(regs->pt.flags, &user->regs.eflags); | |
135 | put_user_ex(regs->pt.sp, &user->regs.esp); | |
136 | put_user_ex(regs->pt.ss, &user->regs.ss); | |
137 | put_user_ex(regs->es, &user->regs.es); | |
138 | put_user_ex(regs->ds, &user->regs.ds); | |
139 | put_user_ex(regs->fs, &user->regs.fs); | |
140 | put_user_ex(regs->gs, &user->regs.gs); | |
141 | ||
9fda6a06 | 142 | put_user_ex(vm86->screen_bitmap, &user->screen_bitmap); |
ed0b2edb BG |
143 | } put_user_catch(err); |
144 | if (err) { | |
13426356 | 145 | pr_alert("could not access userspace vm86 info\n"); |
1da177e4 LT |
146 | do_exit(SIGSEGV); |
147 | } | |
148 | ||
da51da18 | 149 | preempt_disable(); |
9fda6a06 | 150 | tsk->thread.sp0 = vm86->saved_sp0; |
ed0b2edb | 151 | tsk->thread.sysenter_cs = __KERNEL_CS; |
46f5a10a | 152 | update_sp0(tsk); |
bd7dc5a6 | 153 | refresh_sysenter_cs(&tsk->thread); |
9fda6a06 | 154 | vm86->saved_sp0 = 0; |
da51da18 | 155 | preempt_enable(); |
1da177e4 | 156 | |
5ed92a8a | 157 | memcpy(®s->pt, &vm86->regs32, sizeof(struct pt_regs)); |
49d26b6e | 158 | |
5ed92a8a | 159 | lazy_load_gs(vm86->regs32.gs); |
49d26b6e | 160 | |
5ed92a8a | 161 | regs->pt.ax = retval; |
1da177e4 LT |
162 | } |
163 | ||
60ec5585 | 164 | static void mark_screen_rdonly(struct mm_struct *mm) |
1da177e4 | 165 | { |
3ba5b5ea KS |
166 | struct vm_area_struct *vma; |
167 | spinlock_t *ptl; | |
1da177e4 | 168 | pgd_t *pgd; |
e0c4f675 | 169 | p4d_t *p4d; |
1da177e4 LT |
170 | pud_t *pud; |
171 | pmd_t *pmd; | |
60ec5585 | 172 | pte_t *pte; |
1da177e4 LT |
173 | int i; |
174 | ||
1a5a9906 | 175 | down_write(&mm->mmap_sem); |
60ec5585 | 176 | pgd = pgd_offset(mm, 0xA0000); |
1da177e4 LT |
177 | if (pgd_none_or_clear_bad(pgd)) |
178 | goto out; | |
e0c4f675 KS |
179 | p4d = p4d_offset(pgd, 0xA0000); |
180 | if (p4d_none_or_clear_bad(p4d)) | |
181 | goto out; | |
182 | pud = pud_offset(p4d, 0xA0000); | |
1da177e4 LT |
183 | if (pud_none_or_clear_bad(pud)) |
184 | goto out; | |
185 | pmd = pmd_offset(pud, 0xA0000); | |
78ddc534 KS |
186 | |
187 | if (pmd_trans_huge(*pmd)) { | |
3ba5b5ea | 188 | vma = find_vma(mm, 0xA0000); |
78ddc534 KS |
189 | split_huge_pmd(vma, pmd, 0xA0000); |
190 | } | |
1da177e4 LT |
191 | if (pmd_none_or_clear_bad(pmd)) |
192 | goto out; | |
60ec5585 | 193 | pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); |
1da177e4 LT |
194 | for (i = 0; i < 32; i++) { |
195 | if (pte_present(*pte)) | |
196 | set_pte(pte, pte_wrprotect(*pte)); | |
197 | pte++; | |
198 | } | |
60ec5585 | 199 | pte_unmap_unlock(pte, ptl); |
1da177e4 | 200 | out: |
1a5a9906 | 201 | up_write(&mm->mmap_sem); |
9ccee237 | 202 | flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, 0UL); |
1da177e4 LT |
203 | } |
204 | ||
205 | ||
206 | ||
207 | static int do_vm86_irq_handling(int subfunction, int irqnumber); | |
13426356 | 208 | static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus); |
1da177e4 | 209 | |
13426356 | 210 | SYSCALL_DEFINE1(vm86old, struct vm86_struct __user *, user_vm86) |
1da177e4 | 211 | { |
13426356 | 212 | return do_sys_vm86((struct vm86plus_struct __user *) user_vm86, false); |
1da177e4 LT |
213 | } |
214 | ||
215 | ||
5522ddb3 | 216 | SYSCALL_DEFINE2(vm86, unsigned long, cmd, unsigned long, arg) |
1da177e4 | 217 | { |
f1382f15 | 218 | switch (cmd) { |
83e714e8 PC |
219 | case VM86_REQUEST_IRQ: |
220 | case VM86_FREE_IRQ: | |
221 | case VM86_GET_IRQ_BITS: | |
222 | case VM86_GET_AND_RESET_IRQ: | |
5522ddb3 | 223 | return do_vm86_irq_handling(cmd, (int)arg); |
83e714e8 PC |
224 | case VM86_PLUS_INSTALL_CHECK: |
225 | /* | |
226 | * NOTE: on old vm86 stuff this will return the error | |
227 | * from access_ok(), because the subfunction is | |
228 | * interpreted as (invalid) address to vm86_struct. | |
229 | * So the installation check works. | |
230 | */ | |
5522ddb3 | 231 | return 0; |
1da177e4 LT |
232 | } |
233 | ||
234 | /* we come here only for functions VM86_ENTER, VM86_ENTER_NO_BYPASS */ | |
90c6085a | 235 | return do_sys_vm86((struct vm86plus_struct __user *) arg, true); |
1da177e4 LT |
236 | } |
237 | ||
238 | ||
13426356 | 239 | static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus) |
1da177e4 | 240 | { |
ed0b2edb | 241 | struct task_struct *tsk = current; |
9fda6a06 | 242 | struct vm86 *vm86 = tsk->thread.vm86; |
90c6085a | 243 | struct kernel_vm86_regs vm86regs; |
5ed92a8a | 244 | struct pt_regs *regs = current_pt_regs(); |
ed0b2edb BG |
245 | unsigned long err = 0; |
246 | ||
76fc5e7b AL |
247 | err = security_mmap_addr(0); |
248 | if (err) { | |
249 | /* | |
250 | * vm86 cannot virtualize the address space, so vm86 users | |
251 | * need to manage the low 1MB themselves using mmap. Given | |
252 | * that BIOS places important data in the first page, vm86 | |
253 | * is essentially useless if mmap_min_addr != 0. DOSEMU, | |
254 | * for example, won't even bother trying to use vm86 if it | |
255 | * can't map a page at virtual address 0. | |
256 | * | |
257 | * To reduce the available kernel attack surface, simply | |
258 | * disallow vm86(old) for users who cannot mmap at va 0. | |
259 | * | |
260 | * The implementation of security_mmap_addr will allow | |
261 | * suitably privileged users to map va 0 even if | |
262 | * vm.mmap_min_addr is set above 0, and we want this | |
263 | * behavior for vm86 as well, as it ensures that legacy | |
264 | * tools like vbetool will not fail just because of | |
265 | * vm.mmap_min_addr. | |
266 | */ | |
267 | 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", | |
268 | current->comm, task_pid_nr(current), | |
269 | from_kuid_munged(&init_user_ns, current_uid())); | |
270 | return -EPERM; | |
271 | } | |
272 | ||
9fda6a06 BG |
273 | if (!vm86) { |
274 | if (!(vm86 = kzalloc(sizeof(*vm86), GFP_KERNEL))) | |
275 | return -ENOMEM; | |
276 | tsk->thread.vm86 = vm86; | |
277 | } | |
278 | if (vm86->saved_sp0) | |
ed0b2edb BG |
279 | return -EPERM; |
280 | ||
13426356 | 281 | if (!access_ok(VERIFY_READ, user_vm86, plus ? |
ed0b2edb BG |
282 | sizeof(struct vm86_struct) : |
283 | sizeof(struct vm86plus_struct))) | |
284 | return -EFAULT; | |
285 | ||
90c6085a | 286 | memset(&vm86regs, 0, sizeof(vm86regs)); |
ed0b2edb BG |
287 | get_user_try { |
288 | unsigned short seg; | |
13426356 BG |
289 | get_user_ex(vm86regs.pt.bx, &user_vm86->regs.ebx); |
290 | get_user_ex(vm86regs.pt.cx, &user_vm86->regs.ecx); | |
291 | get_user_ex(vm86regs.pt.dx, &user_vm86->regs.edx); | |
292 | get_user_ex(vm86regs.pt.si, &user_vm86->regs.esi); | |
293 | get_user_ex(vm86regs.pt.di, &user_vm86->regs.edi); | |
294 | get_user_ex(vm86regs.pt.bp, &user_vm86->regs.ebp); | |
295 | get_user_ex(vm86regs.pt.ax, &user_vm86->regs.eax); | |
296 | get_user_ex(vm86regs.pt.ip, &user_vm86->regs.eip); | |
297 | get_user_ex(seg, &user_vm86->regs.cs); | |
90c6085a | 298 | vm86regs.pt.cs = seg; |
13426356 BG |
299 | get_user_ex(vm86regs.pt.flags, &user_vm86->regs.eflags); |
300 | get_user_ex(vm86regs.pt.sp, &user_vm86->regs.esp); | |
301 | get_user_ex(seg, &user_vm86->regs.ss); | |
90c6085a | 302 | vm86regs.pt.ss = seg; |
13426356 BG |
303 | get_user_ex(vm86regs.es, &user_vm86->regs.es); |
304 | get_user_ex(vm86regs.ds, &user_vm86->regs.ds); | |
305 | get_user_ex(vm86regs.fs, &user_vm86->regs.fs); | |
306 | get_user_ex(vm86regs.gs, &user_vm86->regs.gs); | |
307 | ||
308 | get_user_ex(vm86->flags, &user_vm86->flags); | |
309 | get_user_ex(vm86->screen_bitmap, &user_vm86->screen_bitmap); | |
310 | get_user_ex(vm86->cpu_type, &user_vm86->cpu_type); | |
ed0b2edb BG |
311 | } get_user_catch(err); |
312 | if (err) | |
313 | return err; | |
314 | ||
13426356 BG |
315 | if (copy_from_user(&vm86->int_revectored, |
316 | &user_vm86->int_revectored, | |
ed0b2edb BG |
317 | sizeof(struct revectored_struct))) |
318 | return -EFAULT; | |
13426356 BG |
319 | if (copy_from_user(&vm86->int21_revectored, |
320 | &user_vm86->int21_revectored, | |
ed0b2edb BG |
321 | sizeof(struct revectored_struct))) |
322 | return -EFAULT; | |
323 | if (plus) { | |
13426356 | 324 | if (copy_from_user(&vm86->vm86plus, &user_vm86->vm86plus, |
ed0b2edb BG |
325 | sizeof(struct vm86plus_info_struct))) |
326 | return -EFAULT; | |
d4ce0f26 BG |
327 | vm86->vm86plus.is_vm86pus = 1; |
328 | } else | |
329 | memset(&vm86->vm86plus, 0, | |
330 | sizeof(struct vm86plus_info_struct)); | |
5ed92a8a BG |
331 | |
332 | memcpy(&vm86->regs32, regs, sizeof(struct pt_regs)); | |
13426356 | 333 | vm86->user_vm86 = user_vm86; |
1da177e4 LT |
334 | |
335 | /* | |
65ea5b03 | 336 | * The flags register is also special: we cannot trust that the user |
1da177e4 LT |
337 | * has set it up safely, so this makes sure interrupt etc flags are |
338 | * inherited from protected mode. | |
339 | */ | |
90c6085a BG |
340 | VEFLAGS = vm86regs.pt.flags; |
341 | vm86regs.pt.flags &= SAFE_MASK; | |
5ed92a8a | 342 | vm86regs.pt.flags |= regs->flags & ~SAFE_MASK; |
90c6085a | 343 | vm86regs.pt.flags |= X86_VM_MASK; |
1da177e4 | 344 | |
5ed92a8a | 345 | vm86regs.pt.orig_ax = regs->orig_ax; |
df1ae9a5 | 346 | |
d4ce0f26 | 347 | switch (vm86->cpu_type) { |
83e714e8 | 348 | case CPU_286: |
decd275e | 349 | vm86->veflags_mask = 0; |
83e714e8 PC |
350 | break; |
351 | case CPU_386: | |
decd275e | 352 | vm86->veflags_mask = X86_EFLAGS_NT | X86_EFLAGS_IOPL; |
83e714e8 PC |
353 | break; |
354 | case CPU_486: | |
decd275e | 355 | vm86->veflags_mask = X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL; |
83e714e8 PC |
356 | break; |
357 | default: | |
decd275e | 358 | vm86->veflags_mask = X86_EFLAGS_ID | X86_EFLAGS_AC | X86_EFLAGS_NT | X86_EFLAGS_IOPL; |
83e714e8 | 359 | break; |
1da177e4 LT |
360 | } |
361 | ||
362 | /* | |
5ed92a8a | 363 | * Save old state |
1da177e4 | 364 | */ |
9fda6a06 | 365 | vm86->saved_sp0 = tsk->thread.sp0; |
5ed92a8a | 366 | lazy_save_gs(vm86->regs32.gs); |
1da177e4 | 367 | |
5ed92a8a | 368 | /* make room for real-mode segments */ |
da51da18 | 369 | preempt_disable(); |
5ed92a8a | 370 | tsk->thread.sp0 += 16; |
362f924b | 371 | |
bd7dc5a6 | 372 | if (static_cpu_has(X86_FEATURE_SEP)) { |
1da177e4 | 373 | tsk->thread.sysenter_cs = 0; |
bd7dc5a6 AL |
374 | refresh_sysenter_cs(&tsk->thread); |
375 | } | |
362f924b | 376 | |
46f5a10a | 377 | update_sp0(tsk); |
da51da18 | 378 | preempt_enable(); |
1da177e4 | 379 | |
d4ce0f26 | 380 | if (vm86->flags & VM86_SCREEN_BITMAP) |
60ec5585 | 381 | mark_screen_rdonly(tsk->mm); |
7e7f8a03 | 382 | |
5ed92a8a BG |
383 | memcpy((struct kernel_vm86_regs *)regs, &vm86regs, sizeof(vm86regs)); |
384 | force_iret(); | |
385 | return regs->ax; | |
1da177e4 LT |
386 | } |
387 | ||
83e714e8 | 388 | static inline void set_IF(struct kernel_vm86_regs *regs) |
1da177e4 | 389 | { |
a5c15d41 | 390 | VEFLAGS |= X86_EFLAGS_VIF; |
1da177e4 LT |
391 | } |
392 | ||
83e714e8 | 393 | static inline void clear_IF(struct kernel_vm86_regs *regs) |
1da177e4 | 394 | { |
a5c15d41 | 395 | VEFLAGS &= ~X86_EFLAGS_VIF; |
1da177e4 LT |
396 | } |
397 | ||
83e714e8 | 398 | static inline void clear_TF(struct kernel_vm86_regs *regs) |
1da177e4 | 399 | { |
a5c15d41 | 400 | regs->pt.flags &= ~X86_EFLAGS_TF; |
1da177e4 LT |
401 | } |
402 | ||
83e714e8 | 403 | static inline void clear_AC(struct kernel_vm86_regs *regs) |
1da177e4 | 404 | { |
a5c15d41 | 405 | regs->pt.flags &= ~X86_EFLAGS_AC; |
1da177e4 LT |
406 | } |
407 | ||
83e714e8 PC |
408 | /* |
409 | * It is correct to call set_IF(regs) from the set_vflags_* | |
1da177e4 LT |
410 | * functions. However someone forgot to call clear_IF(regs) |
411 | * in the opposite case. | |
412 | * After the command sequence CLI PUSHF STI POPF you should | |
ab4a574e | 413 | * end up with interrupts disabled, but you ended up with |
1da177e4 LT |
414 | * interrupts enabled. |
415 | * ( I was testing my own changes, but the only bug I | |
416 | * could find was in a function I had not changed. ) | |
417 | * [KD] | |
418 | */ | |
419 | ||
83e714e8 | 420 | static inline void set_vflags_long(unsigned long flags, struct kernel_vm86_regs *regs) |
1da177e4 | 421 | { |
decd275e | 422 | set_flags(VEFLAGS, flags, current->thread.vm86->veflags_mask); |
65ea5b03 | 423 | set_flags(regs->pt.flags, flags, SAFE_MASK); |
a5c15d41 | 424 | if (flags & X86_EFLAGS_IF) |
1da177e4 LT |
425 | set_IF(regs); |
426 | else | |
427 | clear_IF(regs); | |
428 | } | |
429 | ||
83e714e8 | 430 | static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs *regs) |
1da177e4 | 431 | { |
decd275e | 432 | set_flags(VFLAGS, flags, current->thread.vm86->veflags_mask); |
65ea5b03 | 433 | set_flags(regs->pt.flags, flags, SAFE_MASK); |
a5c15d41 | 434 | if (flags & X86_EFLAGS_IF) |
1da177e4 LT |
435 | set_IF(regs); |
436 | else | |
437 | clear_IF(regs); | |
438 | } | |
439 | ||
83e714e8 | 440 | static inline unsigned long get_vflags(struct kernel_vm86_regs *regs) |
1da177e4 | 441 | { |
65ea5b03 | 442 | unsigned long flags = regs->pt.flags & RETURN_MASK; |
1da177e4 | 443 | |
a5c15d41 | 444 | if (VEFLAGS & X86_EFLAGS_VIF) |
445 | flags |= X86_EFLAGS_IF; | |
446 | flags |= X86_EFLAGS_IOPL; | |
decd275e | 447 | return flags | (VEFLAGS & current->thread.vm86->veflags_mask); |
1da177e4 LT |
448 | } |
449 | ||
83e714e8 | 450 | static inline int is_revectored(int nr, struct revectored_struct *bitmap) |
1da177e4 | 451 | { |
2823d4da | 452 | return test_bit(nr, bitmap->__map); |
1da177e4 LT |
453 | } |
454 | ||
455 | #define val_byte(val, n) (((__u8 *)&val)[n]) | |
456 | ||
457 | #define pushb(base, ptr, val, err_label) \ | |
458 | do { \ | |
459 | __u8 __val = val; \ | |
460 | ptr--; \ | |
461 | if (put_user(__val, base + ptr) < 0) \ | |
462 | goto err_label; \ | |
83e714e8 | 463 | } while (0) |
1da177e4 LT |
464 | |
465 | #define pushw(base, ptr, val, err_label) \ | |
466 | do { \ | |
467 | __u16 __val = val; \ | |
468 | ptr--; \ | |
469 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
470 | goto err_label; \ | |
471 | ptr--; \ | |
472 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
473 | goto err_label; \ | |
83e714e8 | 474 | } while (0) |
1da177e4 LT |
475 | |
476 | #define pushl(base, ptr, val, err_label) \ | |
477 | do { \ | |
478 | __u32 __val = val; \ | |
479 | ptr--; \ | |
480 | if (put_user(val_byte(__val, 3), base + ptr) < 0) \ | |
481 | goto err_label; \ | |
482 | ptr--; \ | |
483 | if (put_user(val_byte(__val, 2), base + ptr) < 0) \ | |
484 | goto err_label; \ | |
485 | ptr--; \ | |
486 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
487 | goto err_label; \ | |
488 | ptr--; \ | |
489 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
490 | goto err_label; \ | |
83e714e8 | 491 | } while (0) |
1da177e4 LT |
492 | |
493 | #define popb(base, ptr, err_label) \ | |
494 | ({ \ | |
495 | __u8 __res; \ | |
496 | if (get_user(__res, base + ptr) < 0) \ | |
497 | goto err_label; \ | |
498 | ptr++; \ | |
499 | __res; \ | |
500 | }) | |
501 | ||
502 | #define popw(base, ptr, err_label) \ | |
503 | ({ \ | |
504 | __u16 __res; \ | |
505 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
506 | goto err_label; \ | |
507 | ptr++; \ | |
508 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
509 | goto err_label; \ | |
510 | ptr++; \ | |
511 | __res; \ | |
512 | }) | |
513 | ||
514 | #define popl(base, ptr, err_label) \ | |
515 | ({ \ | |
516 | __u32 __res; \ | |
517 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
518 | goto err_label; \ | |
519 | ptr++; \ | |
520 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
521 | goto err_label; \ | |
522 | ptr++; \ | |
523 | if (get_user(val_byte(__res, 2), base + ptr) < 0) \ | |
524 | goto err_label; \ | |
525 | ptr++; \ | |
526 | if (get_user(val_byte(__res, 3), base + ptr) < 0) \ | |
527 | goto err_label; \ | |
528 | ptr++; \ | |
529 | __res; \ | |
530 | }) | |
531 | ||
532 | /* There are so many possible reasons for this function to return | |
533 | * VM86_INTx, so adding another doesn't bother me. We can expect | |
534 | * userspace programs to be able to handle it. (Getting a problem | |
535 | * in userspace is always better than an Oops anyway.) [KD] | |
536 | */ | |
537 | static void do_int(struct kernel_vm86_regs *regs, int i, | |
83e714e8 | 538 | unsigned char __user *ssp, unsigned short sp) |
1da177e4 LT |
539 | { |
540 | unsigned long __user *intr_ptr; | |
541 | unsigned long segoffs; | |
90c6085a | 542 | struct vm86 *vm86 = current->thread.vm86; |
1da177e4 | 543 | |
65ea5b03 | 544 | if (regs->pt.cs == BIOSSEG) |
1da177e4 | 545 | goto cannot_handle; |
d4ce0f26 | 546 | if (is_revectored(i, &vm86->int_revectored)) |
1da177e4 | 547 | goto cannot_handle; |
d4ce0f26 | 548 | if (i == 0x21 && is_revectored(AH(regs), &vm86->int21_revectored)) |
1da177e4 LT |
549 | goto cannot_handle; |
550 | intr_ptr = (unsigned long __user *) (i << 2); | |
551 | if (get_user(segoffs, intr_ptr)) | |
552 | goto cannot_handle; | |
553 | if ((segoffs >> 16) == BIOSSEG) | |
554 | goto cannot_handle; | |
555 | pushw(ssp, sp, get_vflags(regs), cannot_handle); | |
65ea5b03 | 556 | pushw(ssp, sp, regs->pt.cs, cannot_handle); |
1da177e4 | 557 | pushw(ssp, sp, IP(regs), cannot_handle); |
65ea5b03 | 558 | regs->pt.cs = segoffs >> 16; |
1da177e4 LT |
559 | SP(regs) -= 6; |
560 | IP(regs) = segoffs & 0xffff; | |
561 | clear_TF(regs); | |
562 | clear_IF(regs); | |
563 | clear_AC(regs); | |
564 | return; | |
565 | ||
566 | cannot_handle: | |
5ed92a8a | 567 | save_v86_state(regs, VM86_INTx + (i << 8)); |
1da177e4 LT |
568 | } |
569 | ||
83e714e8 | 570 | int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno) |
1da177e4 | 571 | { |
90c6085a BG |
572 | struct vm86 *vm86 = current->thread.vm86; |
573 | ||
574 | if (vm86->vm86plus.is_vm86pus) { | |
6554287b | 575 | if ((trapno == 3) || (trapno == 1)) { |
5ed92a8a | 576 | save_v86_state(regs, VM86_TRAP + (trapno << 8)); |
6554287b BO |
577 | return 0; |
578 | } | |
65ea5b03 | 579 | do_int(regs, trapno, (unsigned char __user *) (regs->pt.ss << 4), SP(regs)); |
1da177e4 LT |
580 | return 0; |
581 | } | |
83e714e8 | 582 | if (trapno != 1) |
1da177e4 | 583 | return 1; /* we let this handle by the calling routine */ |
51e7dc70 | 584 | current->thread.trap_nr = trapno; |
1da177e4 | 585 | current->thread.error_code = error_code; |
0f540910 | 586 | force_sig(SIGTRAP, current); |
1da177e4 LT |
587 | return 0; |
588 | } | |
589 | ||
83e714e8 | 590 | void handle_vm86_fault(struct kernel_vm86_regs *regs, long error_code) |
1da177e4 LT |
591 | { |
592 | unsigned char opcode; | |
593 | unsigned char __user *csp; | |
594 | unsigned char __user *ssp; | |
5fd75ebb | 595 | unsigned short ip, sp, orig_flags; |
1da177e4 | 596 | int data32, pref_done; |
d4ce0f26 | 597 | struct vm86plus_info_struct *vmpi = ¤t->thread.vm86->vm86plus; |
1da177e4 LT |
598 | |
599 | #define CHECK_IF_IN_TRAP \ | |
d4ce0f26 | 600 | if (vmpi->vm86dbg_active && vmpi->vm86dbg_TFpendig) \ |
a5c15d41 | 601 | newflags |= X86_EFLAGS_TF |
1da177e4 | 602 | |
65ea5b03 | 603 | orig_flags = *(unsigned short *)®s->pt.flags; |
5fd75ebb | 604 | |
65ea5b03 PA |
605 | csp = (unsigned char __user *) (regs->pt.cs << 4); |
606 | ssp = (unsigned char __user *) (regs->pt.ss << 4); | |
1da177e4 LT |
607 | sp = SP(regs); |
608 | ip = IP(regs); | |
609 | ||
610 | data32 = 0; | |
611 | pref_done = 0; | |
612 | do { | |
613 | switch (opcode = popb(csp, ip, simulate_sigsegv)) { | |
83e714e8 PC |
614 | case 0x66: /* 32-bit data */ data32 = 1; break; |
615 | case 0x67: /* 32-bit address */ break; | |
616 | case 0x2e: /* CS */ break; | |
617 | case 0x3e: /* DS */ break; | |
618 | case 0x26: /* ES */ break; | |
619 | case 0x36: /* SS */ break; | |
620 | case 0x65: /* GS */ break; | |
621 | case 0x64: /* FS */ break; | |
622 | case 0xf2: /* repnz */ break; | |
623 | case 0xf3: /* rep */ break; | |
624 | default: pref_done = 1; | |
1da177e4 LT |
625 | } |
626 | } while (!pref_done); | |
627 | ||
628 | switch (opcode) { | |
629 | ||
630 | /* pushf */ | |
631 | case 0x9c: | |
632 | if (data32) { | |
633 | pushl(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
634 | SP(regs) -= 4; | |
635 | } else { | |
636 | pushw(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
637 | SP(regs) -= 2; | |
638 | } | |
639 | IP(regs) = ip; | |
5ed92a8a | 640 | goto vm86_fault_return; |
1da177e4 LT |
641 | |
642 | /* popf */ | |
643 | case 0x9d: | |
644 | { | |
645 | unsigned long newflags; | |
646 | if (data32) { | |
83e714e8 | 647 | newflags = popl(ssp, sp, simulate_sigsegv); |
1da177e4 LT |
648 | SP(regs) += 4; |
649 | } else { | |
650 | newflags = popw(ssp, sp, simulate_sigsegv); | |
651 | SP(regs) += 2; | |
652 | } | |
653 | IP(regs) = ip; | |
654 | CHECK_IF_IN_TRAP; | |
83e714e8 | 655 | if (data32) |
1da177e4 | 656 | set_vflags_long(newflags, regs); |
83e714e8 | 657 | else |
1da177e4 | 658 | set_vflags_short(newflags, regs); |
83e714e8 | 659 | |
5ed92a8a | 660 | goto check_vip; |
1da177e4 LT |
661 | } |
662 | ||
663 | /* int xx */ | |
664 | case 0xcd: { | |
83e714e8 | 665 | int intno = popb(csp, ip, simulate_sigsegv); |
1da177e4 | 666 | IP(regs) = ip; |
d4ce0f26 | 667 | if (vmpi->vm86dbg_active) { |
5ed92a8a BG |
668 | if ((1 << (intno & 7)) & vmpi->vm86dbg_intxxtab[intno >> 3]) { |
669 | save_v86_state(regs, VM86_INTx + (intno << 8)); | |
670 | return; | |
671 | } | |
1da177e4 LT |
672 | } |
673 | do_int(regs, intno, ssp, sp); | |
674 | return; | |
675 | } | |
676 | ||
677 | /* iret */ | |
678 | case 0xcf: | |
679 | { | |
680 | unsigned long newip; | |
681 | unsigned long newcs; | |
682 | unsigned long newflags; | |
683 | if (data32) { | |
83e714e8 PC |
684 | newip = popl(ssp, sp, simulate_sigsegv); |
685 | newcs = popl(ssp, sp, simulate_sigsegv); | |
686 | newflags = popl(ssp, sp, simulate_sigsegv); | |
1da177e4 LT |
687 | SP(regs) += 12; |
688 | } else { | |
689 | newip = popw(ssp, sp, simulate_sigsegv); | |
690 | newcs = popw(ssp, sp, simulate_sigsegv); | |
691 | newflags = popw(ssp, sp, simulate_sigsegv); | |
692 | SP(regs) += 6; | |
693 | } | |
694 | IP(regs) = newip; | |
65ea5b03 | 695 | regs->pt.cs = newcs; |
1da177e4 LT |
696 | CHECK_IF_IN_TRAP; |
697 | if (data32) { | |
698 | set_vflags_long(newflags, regs); | |
699 | } else { | |
700 | set_vflags_short(newflags, regs); | |
701 | } | |
5ed92a8a | 702 | goto check_vip; |
1da177e4 LT |
703 | } |
704 | ||
705 | /* cli */ | |
706 | case 0xfa: | |
707 | IP(regs) = ip; | |
708 | clear_IF(regs); | |
5ed92a8a | 709 | goto vm86_fault_return; |
1da177e4 LT |
710 | |
711 | /* sti */ | |
712 | /* | |
713 | * Damn. This is incorrect: the 'sti' instruction should actually | |
714 | * enable interrupts after the /next/ instruction. Not good. | |
715 | * | |
716 | * Probably needs some horsing around with the TF flag. Aiee.. | |
717 | */ | |
718 | case 0xfb: | |
719 | IP(regs) = ip; | |
720 | set_IF(regs); | |
5ed92a8a | 721 | goto check_vip; |
1da177e4 LT |
722 | |
723 | default: | |
5ed92a8a | 724 | save_v86_state(regs, VM86_UNKNOWN); |
1da177e4 LT |
725 | } |
726 | ||
727 | return; | |
728 | ||
5ed92a8a BG |
729 | check_vip: |
730 | if (VEFLAGS & X86_EFLAGS_VIP) { | |
731 | save_v86_state(regs, VM86_STI); | |
732 | return; | |
733 | } | |
734 | ||
735 | vm86_fault_return: | |
736 | if (vmpi->force_return_for_pic && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) { | |
737 | save_v86_state(regs, VM86_PICRETURN); | |
738 | return; | |
739 | } | |
740 | if (orig_flags & X86_EFLAGS_TF) | |
741 | handle_vm86_trap(regs, 0, X86_TRAP_DB); | |
742 | return; | |
743 | ||
1da177e4 LT |
744 | simulate_sigsegv: |
745 | /* FIXME: After a long discussion with Stas we finally | |
746 | * agreed, that this is wrong. Here we should | |
747 | * really send a SIGSEGV to the user program. | |
748 | * But how do we create the correct context? We | |
749 | * are inside a general protection fault handler | |
750 | * and has just returned from a page fault handler. | |
751 | * The correct context for the signal handler | |
752 | * should be a mixture of the two, but how do we | |
753 | * get the information? [KD] | |
754 | */ | |
5ed92a8a | 755 | save_v86_state(regs, VM86_UNKNOWN); |
1da177e4 LT |
756 | } |
757 | ||
758 | /* ---------------- vm86 special IRQ passing stuff ----------------- */ | |
759 | ||
760 | #define VM86_IRQNAME "vm86irq" | |
761 | ||
762 | static struct vm86_irqs { | |
763 | struct task_struct *tsk; | |
764 | int sig; | |
765 | } vm86_irqs[16]; | |
766 | ||
767 | static DEFINE_SPINLOCK(irqbits_lock); | |
768 | static int irqbits; | |
769 | ||
83e714e8 | 770 | #define ALLOWED_SIGS (1 /* 0 = don't send a signal */ \ |
1da177e4 | 771 | | (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO) | (1 << SIGURG) \ |
83e714e8 PC |
772 | | (1 << SIGUNUSED)) |
773 | ||
7d12e780 | 774 | static irqreturn_t irq_handler(int intno, void *dev_id) |
1da177e4 LT |
775 | { |
776 | int irq_bit; | |
777 | unsigned long flags; | |
778 | ||
83e714e8 | 779 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 | 780 | irq_bit = 1 << intno; |
83e714e8 | 781 | if ((irqbits & irq_bit) || !vm86_irqs[intno].tsk) |
1da177e4 LT |
782 | goto out; |
783 | irqbits |= irq_bit; | |
784 | if (vm86_irqs[intno].sig) | |
785 | send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1); | |
1da177e4 LT |
786 | /* |
787 | * IRQ will be re-enabled when user asks for the irq (whether | |
788 | * polling or as a result of the signal) | |
789 | */ | |
ad671423 PP |
790 | disable_irq_nosync(intno); |
791 | spin_unlock_irqrestore(&irqbits_lock, flags); | |
1da177e4 LT |
792 | return IRQ_HANDLED; |
793 | ||
794 | out: | |
83e714e8 | 795 | spin_unlock_irqrestore(&irqbits_lock, flags); |
1da177e4 LT |
796 | return IRQ_NONE; |
797 | } | |
798 | ||
799 | static inline void free_vm86_irq(int irqnumber) | |
800 | { | |
801 | unsigned long flags; | |
802 | ||
803 | free_irq(irqnumber, NULL); | |
804 | vm86_irqs[irqnumber].tsk = NULL; | |
805 | ||
83e714e8 | 806 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 | 807 | irqbits &= ~(1 << irqnumber); |
83e714e8 | 808 | spin_unlock_irqrestore(&irqbits_lock, flags); |
1da177e4 LT |
809 | } |
810 | ||
811 | void release_vm86_irqs(struct task_struct *task) | |
812 | { | |
813 | int i; | |
814 | for (i = FIRST_VM86_IRQ ; i <= LAST_VM86_IRQ; i++) | |
815 | if (vm86_irqs[i].tsk == task) | |
816 | free_vm86_irq(i); | |
817 | } | |
818 | ||
819 | static inline int get_and_reset_irq(int irqnumber) | |
820 | { | |
821 | int bit; | |
822 | unsigned long flags; | |
ad671423 | 823 | int ret = 0; |
83e714e8 | 824 | |
1da177e4 LT |
825 | if (invalid_vm86_irq(irqnumber)) return 0; |
826 | if (vm86_irqs[irqnumber].tsk != current) return 0; | |
83e714e8 | 827 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 LT |
828 | bit = irqbits & (1 << irqnumber); |
829 | irqbits &= ~bit; | |
ad671423 PP |
830 | if (bit) { |
831 | enable_irq(irqnumber); | |
832 | ret = 1; | |
833 | } | |
834 | ||
83e714e8 | 835 | spin_unlock_irqrestore(&irqbits_lock, flags); |
ad671423 | 836 | return ret; |
1da177e4 LT |
837 | } |
838 | ||
839 | ||
840 | static int do_vm86_irq_handling(int subfunction, int irqnumber) | |
841 | { | |
842 | int ret; | |
843 | switch (subfunction) { | |
844 | case VM86_GET_AND_RESET_IRQ: { | |
845 | return get_and_reset_irq(irqnumber); | |
846 | } | |
847 | case VM86_GET_IRQ_BITS: { | |
848 | return irqbits; | |
849 | } | |
850 | case VM86_REQUEST_IRQ: { | |
851 | int sig = irqnumber >> 8; | |
852 | int irq = irqnumber & 255; | |
853 | if (!capable(CAP_SYS_ADMIN)) return -EPERM; | |
854 | if (!((1 << sig) & ALLOWED_SIGS)) return -EPERM; | |
855 | if (invalid_vm86_irq(irq)) return -EPERM; | |
856 | if (vm86_irqs[irq].tsk) return -EPERM; | |
857 | ret = request_irq(irq, &irq_handler, 0, VM86_IRQNAME, NULL); | |
858 | if (ret) return ret; | |
859 | vm86_irqs[irq].sig = sig; | |
860 | vm86_irqs[irq].tsk = current; | |
861 | return irq; | |
862 | } | |
863 | case VM86_FREE_IRQ: { | |
864 | if (invalid_vm86_irq(irqnumber)) return -EPERM; | |
865 | if (!vm86_irqs[irqnumber].tsk) return 0; | |
866 | if (vm86_irqs[irqnumber].tsk != current) return -EPERM; | |
867 | free_vm86_irq(irqnumber); | |
868 | return 0; | |
869 | } | |
870 | } | |
871 | return -EINVAL; | |
872 | } | |
873 |