Commit | Line | Data |
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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> |
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 LT |
96 | { |
97 | struct tss_struct *tss; | |
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 | ||
24933b82 | 149 | tss = &per_cpu(cpu_tss, get_cpu()); |
9fda6a06 | 150 | tsk->thread.sp0 = vm86->saved_sp0; |
ed0b2edb BG |
151 | tsk->thread.sysenter_cs = __KERNEL_CS; |
152 | load_sp0(tss, &tsk->thread); | |
9fda6a06 | 153 | vm86->saved_sp0 = 0; |
1da177e4 LT |
154 | put_cpu(); |
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 LT |
239 | { |
240 | struct tss_struct *tss; | |
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 | |
24933b82 | 368 | tss = &per_cpu(cpu_tss, get_cpu()); |
5ed92a8a BG |
369 | /* make room for real-mode segments */ |
370 | tsk->thread.sp0 += 16; | |
362f924b | 371 | |
bc696ca0 | 372 | if (static_cpu_has(X86_FEATURE_SEP)) |
1da177e4 | 373 | tsk->thread.sysenter_cs = 0; |
362f924b | 374 | |
faca6227 | 375 | load_sp0(tss, &tsk->thread); |
1da177e4 LT |
376 | put_cpu(); |
377 | ||
d4ce0f26 | 378 | if (vm86->flags & VM86_SCREEN_BITMAP) |
60ec5585 | 379 | mark_screen_rdonly(tsk->mm); |
7e7f8a03 | 380 | |
5ed92a8a BG |
381 | memcpy((struct kernel_vm86_regs *)regs, &vm86regs, sizeof(vm86regs)); |
382 | force_iret(); | |
383 | return regs->ax; | |
1da177e4 LT |
384 | } |
385 | ||
83e714e8 | 386 | static inline void set_IF(struct kernel_vm86_regs *regs) |
1da177e4 | 387 | { |
a5c15d41 | 388 | VEFLAGS |= X86_EFLAGS_VIF; |
1da177e4 LT |
389 | } |
390 | ||
83e714e8 | 391 | static inline void clear_IF(struct kernel_vm86_regs *regs) |
1da177e4 | 392 | { |
a5c15d41 | 393 | VEFLAGS &= ~X86_EFLAGS_VIF; |
1da177e4 LT |
394 | } |
395 | ||
83e714e8 | 396 | static inline void clear_TF(struct kernel_vm86_regs *regs) |
1da177e4 | 397 | { |
a5c15d41 | 398 | regs->pt.flags &= ~X86_EFLAGS_TF; |
1da177e4 LT |
399 | } |
400 | ||
83e714e8 | 401 | static inline void clear_AC(struct kernel_vm86_regs *regs) |
1da177e4 | 402 | { |
a5c15d41 | 403 | regs->pt.flags &= ~X86_EFLAGS_AC; |
1da177e4 LT |
404 | } |
405 | ||
83e714e8 PC |
406 | /* |
407 | * It is correct to call set_IF(regs) from the set_vflags_* | |
1da177e4 LT |
408 | * functions. However someone forgot to call clear_IF(regs) |
409 | * in the opposite case. | |
410 | * After the command sequence CLI PUSHF STI POPF you should | |
ab4a574e | 411 | * end up with interrupts disabled, but you ended up with |
1da177e4 LT |
412 | * interrupts enabled. |
413 | * ( I was testing my own changes, but the only bug I | |
414 | * could find was in a function I had not changed. ) | |
415 | * [KD] | |
416 | */ | |
417 | ||
83e714e8 | 418 | static inline void set_vflags_long(unsigned long flags, struct kernel_vm86_regs *regs) |
1da177e4 | 419 | { |
decd275e | 420 | set_flags(VEFLAGS, flags, current->thread.vm86->veflags_mask); |
65ea5b03 | 421 | set_flags(regs->pt.flags, flags, SAFE_MASK); |
a5c15d41 | 422 | if (flags & X86_EFLAGS_IF) |
1da177e4 LT |
423 | set_IF(regs); |
424 | else | |
425 | clear_IF(regs); | |
426 | } | |
427 | ||
83e714e8 | 428 | static inline void set_vflags_short(unsigned short flags, struct kernel_vm86_regs *regs) |
1da177e4 | 429 | { |
decd275e | 430 | set_flags(VFLAGS, flags, current->thread.vm86->veflags_mask); |
65ea5b03 | 431 | set_flags(regs->pt.flags, flags, SAFE_MASK); |
a5c15d41 | 432 | if (flags & X86_EFLAGS_IF) |
1da177e4 LT |
433 | set_IF(regs); |
434 | else | |
435 | clear_IF(regs); | |
436 | } | |
437 | ||
83e714e8 | 438 | static inline unsigned long get_vflags(struct kernel_vm86_regs *regs) |
1da177e4 | 439 | { |
65ea5b03 | 440 | unsigned long flags = regs->pt.flags & RETURN_MASK; |
1da177e4 | 441 | |
a5c15d41 | 442 | if (VEFLAGS & X86_EFLAGS_VIF) |
443 | flags |= X86_EFLAGS_IF; | |
444 | flags |= X86_EFLAGS_IOPL; | |
decd275e | 445 | return flags | (VEFLAGS & current->thread.vm86->veflags_mask); |
1da177e4 LT |
446 | } |
447 | ||
83e714e8 | 448 | static inline int is_revectored(int nr, struct revectored_struct *bitmap) |
1da177e4 | 449 | { |
2823d4da | 450 | return test_bit(nr, bitmap->__map); |
1da177e4 LT |
451 | } |
452 | ||
453 | #define val_byte(val, n) (((__u8 *)&val)[n]) | |
454 | ||
455 | #define pushb(base, ptr, val, err_label) \ | |
456 | do { \ | |
457 | __u8 __val = val; \ | |
458 | ptr--; \ | |
459 | if (put_user(__val, base + ptr) < 0) \ | |
460 | goto err_label; \ | |
83e714e8 | 461 | } while (0) |
1da177e4 LT |
462 | |
463 | #define pushw(base, ptr, val, err_label) \ | |
464 | do { \ | |
465 | __u16 __val = val; \ | |
466 | ptr--; \ | |
467 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
468 | goto err_label; \ | |
469 | ptr--; \ | |
470 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
471 | goto err_label; \ | |
83e714e8 | 472 | } while (0) |
1da177e4 LT |
473 | |
474 | #define pushl(base, ptr, val, err_label) \ | |
475 | do { \ | |
476 | __u32 __val = val; \ | |
477 | ptr--; \ | |
478 | if (put_user(val_byte(__val, 3), base + ptr) < 0) \ | |
479 | goto err_label; \ | |
480 | ptr--; \ | |
481 | if (put_user(val_byte(__val, 2), base + ptr) < 0) \ | |
482 | goto err_label; \ | |
483 | ptr--; \ | |
484 | if (put_user(val_byte(__val, 1), base + ptr) < 0) \ | |
485 | goto err_label; \ | |
486 | ptr--; \ | |
487 | if (put_user(val_byte(__val, 0), base + ptr) < 0) \ | |
488 | goto err_label; \ | |
83e714e8 | 489 | } while (0) |
1da177e4 LT |
490 | |
491 | #define popb(base, ptr, err_label) \ | |
492 | ({ \ | |
493 | __u8 __res; \ | |
494 | if (get_user(__res, base + ptr) < 0) \ | |
495 | goto err_label; \ | |
496 | ptr++; \ | |
497 | __res; \ | |
498 | }) | |
499 | ||
500 | #define popw(base, ptr, err_label) \ | |
501 | ({ \ | |
502 | __u16 __res; \ | |
503 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
504 | goto err_label; \ | |
505 | ptr++; \ | |
506 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
507 | goto err_label; \ | |
508 | ptr++; \ | |
509 | __res; \ | |
510 | }) | |
511 | ||
512 | #define popl(base, ptr, err_label) \ | |
513 | ({ \ | |
514 | __u32 __res; \ | |
515 | if (get_user(val_byte(__res, 0), base + ptr) < 0) \ | |
516 | goto err_label; \ | |
517 | ptr++; \ | |
518 | if (get_user(val_byte(__res, 1), base + ptr) < 0) \ | |
519 | goto err_label; \ | |
520 | ptr++; \ | |
521 | if (get_user(val_byte(__res, 2), base + ptr) < 0) \ | |
522 | goto err_label; \ | |
523 | ptr++; \ | |
524 | if (get_user(val_byte(__res, 3), base + ptr) < 0) \ | |
525 | goto err_label; \ | |
526 | ptr++; \ | |
527 | __res; \ | |
528 | }) | |
529 | ||
530 | /* There are so many possible reasons for this function to return | |
531 | * VM86_INTx, so adding another doesn't bother me. We can expect | |
532 | * userspace programs to be able to handle it. (Getting a problem | |
533 | * in userspace is always better than an Oops anyway.) [KD] | |
534 | */ | |
535 | static void do_int(struct kernel_vm86_regs *regs, int i, | |
83e714e8 | 536 | unsigned char __user *ssp, unsigned short sp) |
1da177e4 LT |
537 | { |
538 | unsigned long __user *intr_ptr; | |
539 | unsigned long segoffs; | |
90c6085a | 540 | struct vm86 *vm86 = current->thread.vm86; |
1da177e4 | 541 | |
65ea5b03 | 542 | if (regs->pt.cs == BIOSSEG) |
1da177e4 | 543 | goto cannot_handle; |
d4ce0f26 | 544 | if (is_revectored(i, &vm86->int_revectored)) |
1da177e4 | 545 | goto cannot_handle; |
d4ce0f26 | 546 | if (i == 0x21 && is_revectored(AH(regs), &vm86->int21_revectored)) |
1da177e4 LT |
547 | goto cannot_handle; |
548 | intr_ptr = (unsigned long __user *) (i << 2); | |
549 | if (get_user(segoffs, intr_ptr)) | |
550 | goto cannot_handle; | |
551 | if ((segoffs >> 16) == BIOSSEG) | |
552 | goto cannot_handle; | |
553 | pushw(ssp, sp, get_vflags(regs), cannot_handle); | |
65ea5b03 | 554 | pushw(ssp, sp, regs->pt.cs, cannot_handle); |
1da177e4 | 555 | pushw(ssp, sp, IP(regs), cannot_handle); |
65ea5b03 | 556 | regs->pt.cs = segoffs >> 16; |
1da177e4 LT |
557 | SP(regs) -= 6; |
558 | IP(regs) = segoffs & 0xffff; | |
559 | clear_TF(regs); | |
560 | clear_IF(regs); | |
561 | clear_AC(regs); | |
562 | return; | |
563 | ||
564 | cannot_handle: | |
5ed92a8a | 565 | save_v86_state(regs, VM86_INTx + (i << 8)); |
1da177e4 LT |
566 | } |
567 | ||
83e714e8 | 568 | int handle_vm86_trap(struct kernel_vm86_regs *regs, long error_code, int trapno) |
1da177e4 | 569 | { |
90c6085a BG |
570 | struct vm86 *vm86 = current->thread.vm86; |
571 | ||
572 | if (vm86->vm86plus.is_vm86pus) { | |
6554287b | 573 | if ((trapno == 3) || (trapno == 1)) { |
5ed92a8a | 574 | save_v86_state(regs, VM86_TRAP + (trapno << 8)); |
6554287b BO |
575 | return 0; |
576 | } | |
65ea5b03 | 577 | do_int(regs, trapno, (unsigned char __user *) (regs->pt.ss << 4), SP(regs)); |
1da177e4 LT |
578 | return 0; |
579 | } | |
83e714e8 | 580 | if (trapno != 1) |
1da177e4 | 581 | return 1; /* we let this handle by the calling routine */ |
51e7dc70 | 582 | current->thread.trap_nr = trapno; |
1da177e4 | 583 | current->thread.error_code = error_code; |
0f540910 | 584 | force_sig(SIGTRAP, current); |
1da177e4 LT |
585 | return 0; |
586 | } | |
587 | ||
83e714e8 | 588 | void handle_vm86_fault(struct kernel_vm86_regs *regs, long error_code) |
1da177e4 LT |
589 | { |
590 | unsigned char opcode; | |
591 | unsigned char __user *csp; | |
592 | unsigned char __user *ssp; | |
5fd75ebb | 593 | unsigned short ip, sp, orig_flags; |
1da177e4 | 594 | int data32, pref_done; |
d4ce0f26 | 595 | struct vm86plus_info_struct *vmpi = ¤t->thread.vm86->vm86plus; |
1da177e4 LT |
596 | |
597 | #define CHECK_IF_IN_TRAP \ | |
d4ce0f26 | 598 | if (vmpi->vm86dbg_active && vmpi->vm86dbg_TFpendig) \ |
a5c15d41 | 599 | newflags |= X86_EFLAGS_TF |
1da177e4 | 600 | |
65ea5b03 | 601 | orig_flags = *(unsigned short *)®s->pt.flags; |
5fd75ebb | 602 | |
65ea5b03 PA |
603 | csp = (unsigned char __user *) (regs->pt.cs << 4); |
604 | ssp = (unsigned char __user *) (regs->pt.ss << 4); | |
1da177e4 LT |
605 | sp = SP(regs); |
606 | ip = IP(regs); | |
607 | ||
608 | data32 = 0; | |
609 | pref_done = 0; | |
610 | do { | |
611 | switch (opcode = popb(csp, ip, simulate_sigsegv)) { | |
83e714e8 PC |
612 | case 0x66: /* 32-bit data */ data32 = 1; break; |
613 | case 0x67: /* 32-bit address */ break; | |
614 | case 0x2e: /* CS */ break; | |
615 | case 0x3e: /* DS */ break; | |
616 | case 0x26: /* ES */ break; | |
617 | case 0x36: /* SS */ break; | |
618 | case 0x65: /* GS */ break; | |
619 | case 0x64: /* FS */ break; | |
620 | case 0xf2: /* repnz */ break; | |
621 | case 0xf3: /* rep */ break; | |
622 | default: pref_done = 1; | |
1da177e4 LT |
623 | } |
624 | } while (!pref_done); | |
625 | ||
626 | switch (opcode) { | |
627 | ||
628 | /* pushf */ | |
629 | case 0x9c: | |
630 | if (data32) { | |
631 | pushl(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
632 | SP(regs) -= 4; | |
633 | } else { | |
634 | pushw(ssp, sp, get_vflags(regs), simulate_sigsegv); | |
635 | SP(regs) -= 2; | |
636 | } | |
637 | IP(regs) = ip; | |
5ed92a8a | 638 | goto vm86_fault_return; |
1da177e4 LT |
639 | |
640 | /* popf */ | |
641 | case 0x9d: | |
642 | { | |
643 | unsigned long newflags; | |
644 | if (data32) { | |
83e714e8 | 645 | newflags = popl(ssp, sp, simulate_sigsegv); |
1da177e4 LT |
646 | SP(regs) += 4; |
647 | } else { | |
648 | newflags = popw(ssp, sp, simulate_sigsegv); | |
649 | SP(regs) += 2; | |
650 | } | |
651 | IP(regs) = ip; | |
652 | CHECK_IF_IN_TRAP; | |
83e714e8 | 653 | if (data32) |
1da177e4 | 654 | set_vflags_long(newflags, regs); |
83e714e8 | 655 | else |
1da177e4 | 656 | set_vflags_short(newflags, regs); |
83e714e8 | 657 | |
5ed92a8a | 658 | goto check_vip; |
1da177e4 LT |
659 | } |
660 | ||
661 | /* int xx */ | |
662 | case 0xcd: { | |
83e714e8 | 663 | int intno = popb(csp, ip, simulate_sigsegv); |
1da177e4 | 664 | IP(regs) = ip; |
d4ce0f26 | 665 | if (vmpi->vm86dbg_active) { |
5ed92a8a BG |
666 | if ((1 << (intno & 7)) & vmpi->vm86dbg_intxxtab[intno >> 3]) { |
667 | save_v86_state(regs, VM86_INTx + (intno << 8)); | |
668 | return; | |
669 | } | |
1da177e4 LT |
670 | } |
671 | do_int(regs, intno, ssp, sp); | |
672 | return; | |
673 | } | |
674 | ||
675 | /* iret */ | |
676 | case 0xcf: | |
677 | { | |
678 | unsigned long newip; | |
679 | unsigned long newcs; | |
680 | unsigned long newflags; | |
681 | if (data32) { | |
83e714e8 PC |
682 | newip = popl(ssp, sp, simulate_sigsegv); |
683 | newcs = popl(ssp, sp, simulate_sigsegv); | |
684 | newflags = popl(ssp, sp, simulate_sigsegv); | |
1da177e4 LT |
685 | SP(regs) += 12; |
686 | } else { | |
687 | newip = popw(ssp, sp, simulate_sigsegv); | |
688 | newcs = popw(ssp, sp, simulate_sigsegv); | |
689 | newflags = popw(ssp, sp, simulate_sigsegv); | |
690 | SP(regs) += 6; | |
691 | } | |
692 | IP(regs) = newip; | |
65ea5b03 | 693 | regs->pt.cs = newcs; |
1da177e4 LT |
694 | CHECK_IF_IN_TRAP; |
695 | if (data32) { | |
696 | set_vflags_long(newflags, regs); | |
697 | } else { | |
698 | set_vflags_short(newflags, regs); | |
699 | } | |
5ed92a8a | 700 | goto check_vip; |
1da177e4 LT |
701 | } |
702 | ||
703 | /* cli */ | |
704 | case 0xfa: | |
705 | IP(regs) = ip; | |
706 | clear_IF(regs); | |
5ed92a8a | 707 | goto vm86_fault_return; |
1da177e4 LT |
708 | |
709 | /* sti */ | |
710 | /* | |
711 | * Damn. This is incorrect: the 'sti' instruction should actually | |
712 | * enable interrupts after the /next/ instruction. Not good. | |
713 | * | |
714 | * Probably needs some horsing around with the TF flag. Aiee.. | |
715 | */ | |
716 | case 0xfb: | |
717 | IP(regs) = ip; | |
718 | set_IF(regs); | |
5ed92a8a | 719 | goto check_vip; |
1da177e4 LT |
720 | |
721 | default: | |
5ed92a8a | 722 | save_v86_state(regs, VM86_UNKNOWN); |
1da177e4 LT |
723 | } |
724 | ||
725 | return; | |
726 | ||
5ed92a8a BG |
727 | check_vip: |
728 | if (VEFLAGS & X86_EFLAGS_VIP) { | |
729 | save_v86_state(regs, VM86_STI); | |
730 | return; | |
731 | } | |
732 | ||
733 | vm86_fault_return: | |
734 | if (vmpi->force_return_for_pic && (VEFLAGS & (X86_EFLAGS_IF | X86_EFLAGS_VIF))) { | |
735 | save_v86_state(regs, VM86_PICRETURN); | |
736 | return; | |
737 | } | |
738 | if (orig_flags & X86_EFLAGS_TF) | |
739 | handle_vm86_trap(regs, 0, X86_TRAP_DB); | |
740 | return; | |
741 | ||
1da177e4 LT |
742 | simulate_sigsegv: |
743 | /* FIXME: After a long discussion with Stas we finally | |
744 | * agreed, that this is wrong. Here we should | |
745 | * really send a SIGSEGV to the user program. | |
746 | * But how do we create the correct context? We | |
747 | * are inside a general protection fault handler | |
748 | * and has just returned from a page fault handler. | |
749 | * The correct context for the signal handler | |
750 | * should be a mixture of the two, but how do we | |
751 | * get the information? [KD] | |
752 | */ | |
5ed92a8a | 753 | save_v86_state(regs, VM86_UNKNOWN); |
1da177e4 LT |
754 | } |
755 | ||
756 | /* ---------------- vm86 special IRQ passing stuff ----------------- */ | |
757 | ||
758 | #define VM86_IRQNAME "vm86irq" | |
759 | ||
760 | static struct vm86_irqs { | |
761 | struct task_struct *tsk; | |
762 | int sig; | |
763 | } vm86_irqs[16]; | |
764 | ||
765 | static DEFINE_SPINLOCK(irqbits_lock); | |
766 | static int irqbits; | |
767 | ||
83e714e8 | 768 | #define ALLOWED_SIGS (1 /* 0 = don't send a signal */ \ |
1da177e4 | 769 | | (1 << SIGUSR1) | (1 << SIGUSR2) | (1 << SIGIO) | (1 << SIGURG) \ |
83e714e8 PC |
770 | | (1 << SIGUNUSED)) |
771 | ||
7d12e780 | 772 | static irqreturn_t irq_handler(int intno, void *dev_id) |
1da177e4 LT |
773 | { |
774 | int irq_bit; | |
775 | unsigned long flags; | |
776 | ||
83e714e8 | 777 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 | 778 | irq_bit = 1 << intno; |
83e714e8 | 779 | if ((irqbits & irq_bit) || !vm86_irqs[intno].tsk) |
1da177e4 LT |
780 | goto out; |
781 | irqbits |= irq_bit; | |
782 | if (vm86_irqs[intno].sig) | |
783 | send_sig(vm86_irqs[intno].sig, vm86_irqs[intno].tsk, 1); | |
1da177e4 LT |
784 | /* |
785 | * IRQ will be re-enabled when user asks for the irq (whether | |
786 | * polling or as a result of the signal) | |
787 | */ | |
ad671423 PP |
788 | disable_irq_nosync(intno); |
789 | spin_unlock_irqrestore(&irqbits_lock, flags); | |
1da177e4 LT |
790 | return IRQ_HANDLED; |
791 | ||
792 | out: | |
83e714e8 | 793 | spin_unlock_irqrestore(&irqbits_lock, flags); |
1da177e4 LT |
794 | return IRQ_NONE; |
795 | } | |
796 | ||
797 | static inline void free_vm86_irq(int irqnumber) | |
798 | { | |
799 | unsigned long flags; | |
800 | ||
801 | free_irq(irqnumber, NULL); | |
802 | vm86_irqs[irqnumber].tsk = NULL; | |
803 | ||
83e714e8 | 804 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 | 805 | irqbits &= ~(1 << irqnumber); |
83e714e8 | 806 | spin_unlock_irqrestore(&irqbits_lock, flags); |
1da177e4 LT |
807 | } |
808 | ||
809 | void release_vm86_irqs(struct task_struct *task) | |
810 | { | |
811 | int i; | |
812 | for (i = FIRST_VM86_IRQ ; i <= LAST_VM86_IRQ; i++) | |
813 | if (vm86_irqs[i].tsk == task) | |
814 | free_vm86_irq(i); | |
815 | } | |
816 | ||
817 | static inline int get_and_reset_irq(int irqnumber) | |
818 | { | |
819 | int bit; | |
820 | unsigned long flags; | |
ad671423 | 821 | int ret = 0; |
83e714e8 | 822 | |
1da177e4 LT |
823 | if (invalid_vm86_irq(irqnumber)) return 0; |
824 | if (vm86_irqs[irqnumber].tsk != current) return 0; | |
83e714e8 | 825 | spin_lock_irqsave(&irqbits_lock, flags); |
1da177e4 LT |
826 | bit = irqbits & (1 << irqnumber); |
827 | irqbits &= ~bit; | |
ad671423 PP |
828 | if (bit) { |
829 | enable_irq(irqnumber); | |
830 | ret = 1; | |
831 | } | |
832 | ||
83e714e8 | 833 | spin_unlock_irqrestore(&irqbits_lock, flags); |
ad671423 | 834 | return ret; |
1da177e4 LT |
835 | } |
836 | ||
837 | ||
838 | static int do_vm86_irq_handling(int subfunction, int irqnumber) | |
839 | { | |
840 | int ret; | |
841 | switch (subfunction) { | |
842 | case VM86_GET_AND_RESET_IRQ: { | |
843 | return get_and_reset_irq(irqnumber); | |
844 | } | |
845 | case VM86_GET_IRQ_BITS: { | |
846 | return irqbits; | |
847 | } | |
848 | case VM86_REQUEST_IRQ: { | |
849 | int sig = irqnumber >> 8; | |
850 | int irq = irqnumber & 255; | |
851 | if (!capable(CAP_SYS_ADMIN)) return -EPERM; | |
852 | if (!((1 << sig) & ALLOWED_SIGS)) return -EPERM; | |
853 | if (invalid_vm86_irq(irq)) return -EPERM; | |
854 | if (vm86_irqs[irq].tsk) return -EPERM; | |
855 | ret = request_irq(irq, &irq_handler, 0, VM86_IRQNAME, NULL); | |
856 | if (ret) return ret; | |
857 | vm86_irqs[irq].sig = sig; | |
858 | vm86_irqs[irq].tsk = current; | |
859 | return irq; | |
860 | } | |
861 | case VM86_FREE_IRQ: { | |
862 | if (invalid_vm86_irq(irqnumber)) return -EPERM; | |
863 | if (!vm86_irqs[irqnumber].tsk) return 0; | |
864 | if (vm86_irqs[irqnumber].tsk != current) return -EPERM; | |
865 | free_vm86_irq(irqnumber); | |
866 | return 0; | |
867 | } | |
868 | } | |
869 | return -EINVAL; | |
870 | } | |
871 |