Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
ba180fd4 | 2 | * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
1da177e4 LT |
3 | * Licensed under the GPL |
4 | */ | |
5 | ||
8192ab42 JD |
6 | #include <linux/mm.h> |
7 | #include <linux/sched.h> | |
8 | #include <asm/unistd.h> | |
12919aa6 | 9 | #include "os.h" |
ba180fd4 | 10 | #include "proc_mm.h" |
858259cf BS |
11 | #include "skas.h" |
12 | #include "skas_ptrace.h" | |
ba180fd4 JD |
13 | #include "sysdep/tls.h" |
14 | ||
15 | extern int modify_ldt(int func, void *ptr, unsigned long bytecount); | |
858259cf | 16 | |
99764fa4 WC |
17 | static long write_ldt_entry(struct mm_id *mm_idp, int func, |
18 | struct user_desc *desc, void **addr, int done) | |
858259cf BS |
19 | { |
20 | long res; | |
21 | ||
ba180fd4 JD |
22 | if (proc_mm) { |
23 | /* | |
24 | * This is a special handling for the case, that the mm to | |
858259cf BS |
25 | * modify isn't current->active_mm. |
26 | * If this is called directly by modify_ldt, | |
27 | * (current->active_mm->context.skas.u == mm_idp) | |
77bf4400 | 28 | * will be true. So no call to __switch_mm(mm_idp) is done. |
858259cf BS |
29 | * If this is called in case of init_new_ldt or PTRACE_LDT, |
30 | * mm_idp won't belong to current->active_mm, but child->mm. | |
31 | * So we need to switch child's mm into our userspace, then | |
32 | * later switch back. | |
33 | * | |
07f4e2c6 | 34 | * Note: I'm unsure: should interrupts be disabled here? |
858259cf | 35 | */ |
ba180fd4 | 36 | if (!current->active_mm || current->active_mm == &init_mm || |
6c738ffa | 37 | mm_idp != ¤t->active_mm->context.id) |
77bf4400 | 38 | __switch_mm(mm_idp); |
858259cf BS |
39 | } |
40 | ||
ba180fd4 | 41 | if (ptrace_ldt) { |
858259cf BS |
42 | struct ptrace_ldt ldt_op = (struct ptrace_ldt) { |
43 | .func = func, | |
44 | .ptr = desc, | |
45 | .bytecount = sizeof(*desc)}; | |
46 | u32 cpu; | |
47 | int pid; | |
48 | ||
ba180fd4 | 49 | if (!proc_mm) |
858259cf BS |
50 | pid = mm_idp->u.pid; |
51 | else { | |
52 | cpu = get_cpu(); | |
53 | pid = userspace_pid[cpu]; | |
54 | } | |
55 | ||
07f4e2c6 | 56 | res = os_ptrace_ldt(pid, 0, (unsigned long) &ldt_op); |
858259cf | 57 | |
ba180fd4 | 58 | if (proc_mm) |
858259cf BS |
59 | put_cpu(); |
60 | } | |
61 | else { | |
62 | void *stub_addr; | |
63 | res = syscall_stub_data(mm_idp, (unsigned long *)desc, | |
64 | (sizeof(*desc) + sizeof(long) - 1) & | |
65 | ~(sizeof(long) - 1), | |
66 | addr, &stub_addr); | |
ba180fd4 | 67 | if (!res) { |
858259cf BS |
68 | unsigned long args[] = { func, |
69 | (unsigned long)stub_addr, | |
70 | sizeof(*desc), | |
71 | 0, 0, 0 }; | |
72 | res = run_syscall_stub(mm_idp, __NR_modify_ldt, args, | |
73 | 0, addr, done); | |
74 | } | |
75 | } | |
76 | ||
ba180fd4 JD |
77 | if (proc_mm) { |
78 | /* | |
79 | * This is the second part of special handling, that makes | |
858259cf BS |
80 | * PTRACE_LDT possible to implement. |
81 | */ | |
ba180fd4 | 82 | if (current->active_mm && current->active_mm != &init_mm && |
6c738ffa JD |
83 | mm_idp != ¤t->active_mm->context.id) |
84 | __switch_mm(¤t->active_mm->context.id); | |
858259cf BS |
85 | } |
86 | ||
87 | return res; | |
88 | } | |
89 | ||
90 | static long read_ldt_from_host(void __user * ptr, unsigned long bytecount) | |
91 | { | |
92 | int res, n; | |
93 | struct ptrace_ldt ptrace_ldt = (struct ptrace_ldt) { | |
94 | .func = 0, | |
95 | .bytecount = bytecount, | |
5cbded58 | 96 | .ptr = kmalloc(bytecount, GFP_KERNEL)}; |
858259cf BS |
97 | u32 cpu; |
98 | ||
ba180fd4 | 99 | if (ptrace_ldt.ptr == NULL) |
858259cf BS |
100 | return -ENOMEM; |
101 | ||
ba180fd4 JD |
102 | /* |
103 | * This is called from sys_modify_ldt only, so userspace_pid gives | |
858259cf BS |
104 | * us the right number |
105 | */ | |
106 | ||
107 | cpu = get_cpu(); | |
07f4e2c6 | 108 | res = os_ptrace_ldt(userspace_pid[cpu], 0, (unsigned long) &ptrace_ldt); |
858259cf | 109 | put_cpu(); |
ba180fd4 | 110 | if (res < 0) |
858259cf BS |
111 | goto out; |
112 | ||
113 | n = copy_to_user(ptr, ptrace_ldt.ptr, res); | |
ba180fd4 | 114 | if (n != 0) |
858259cf BS |
115 | res = -EFAULT; |
116 | ||
117 | out: | |
118 | kfree(ptrace_ldt.ptr); | |
119 | ||
120 | return res; | |
121 | } | |
122 | ||
123 | /* | |
124 | * In skas mode, we hold our own ldt data in UML. | |
125 | * Thus, the code implementing sys_modify_ldt_skas | |
126 | * is very similar to (and mostly stolen from) sys_modify_ldt | |
127 | * for arch/i386/kernel/ldt.c | |
128 | * The routines copied and modified in part are: | |
129 | * - read_ldt | |
130 | * - read_default_ldt | |
131 | * - write_ldt | |
132 | * - sys_modify_ldt_skas | |
133 | */ | |
134 | ||
135 | static int read_ldt(void __user * ptr, unsigned long bytecount) | |
136 | { | |
137 | int i, err = 0; | |
138 | unsigned long size; | |
6c738ffa | 139 | uml_ldt_t * ldt = ¤t->mm->context.ldt; |
858259cf | 140 | |
ba180fd4 | 141 | if (!ldt->entry_count) |
858259cf | 142 | goto out; |
ba180fd4 | 143 | if (bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES) |
858259cf BS |
144 | bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES; |
145 | err = bytecount; | |
146 | ||
ba180fd4 | 147 | if (ptrace_ldt) |
858259cf | 148 | return read_ldt_from_host(ptr, bytecount); |
858259cf | 149 | |
01ac835f | 150 | mutex_lock(&ldt->lock); |
ba180fd4 | 151 | if (ldt->entry_count <= LDT_DIRECT_ENTRIES) { |
858259cf | 152 | size = LDT_ENTRY_SIZE*LDT_DIRECT_ENTRIES; |
ba180fd4 | 153 | if (size > bytecount) |
858259cf | 154 | size = bytecount; |
ba180fd4 | 155 | if (copy_to_user(ptr, ldt->u.entries, size)) |
858259cf BS |
156 | err = -EFAULT; |
157 | bytecount -= size; | |
158 | ptr += size; | |
159 | } | |
160 | else { | |
ba180fd4 JD |
161 | for (i=0; i<ldt->entry_count/LDT_ENTRIES_PER_PAGE && bytecount; |
162 | i++) { | |
858259cf | 163 | size = PAGE_SIZE; |
ba180fd4 | 164 | if (size > bytecount) |
858259cf | 165 | size = bytecount; |
ba180fd4 | 166 | if (copy_to_user(ptr, ldt->u.pages[i], size)) { |
858259cf BS |
167 | err = -EFAULT; |
168 | break; | |
169 | } | |
170 | bytecount -= size; | |
171 | ptr += size; | |
172 | } | |
173 | } | |
01ac835f | 174 | mutex_unlock(&ldt->lock); |
858259cf | 175 | |
ba180fd4 | 176 | if (bytecount == 0 || err == -EFAULT) |
858259cf BS |
177 | goto out; |
178 | ||
ba180fd4 | 179 | if (clear_user(ptr, bytecount)) |
858259cf BS |
180 | err = -EFAULT; |
181 | ||
182 | out: | |
183 | return err; | |
184 | } | |
185 | ||
186 | static int read_default_ldt(void __user * ptr, unsigned long bytecount) | |
187 | { | |
188 | int err; | |
189 | ||
ba180fd4 | 190 | if (bytecount > 5*LDT_ENTRY_SIZE) |
858259cf BS |
191 | bytecount = 5*LDT_ENTRY_SIZE; |
192 | ||
193 | err = bytecount; | |
ba180fd4 JD |
194 | /* |
195 | * UML doesn't support lcall7 and lcall27. | |
858259cf BS |
196 | * So, we don't really have a default ldt, but emulate |
197 | * an empty ldt of common host default ldt size. | |
198 | */ | |
ba180fd4 | 199 | if (clear_user(ptr, bytecount)) |
858259cf BS |
200 | err = -EFAULT; |
201 | ||
202 | return err; | |
203 | } | |
204 | ||
205 | static int write_ldt(void __user * ptr, unsigned long bytecount, int func) | |
206 | { | |
6c738ffa JD |
207 | uml_ldt_t * ldt = ¤t->mm->context.ldt; |
208 | struct mm_id * mm_idp = ¤t->mm->context.id; | |
858259cf BS |
209 | int i, err; |
210 | struct user_desc ldt_info; | |
211 | struct ldt_entry entry0, *ldt_p; | |
212 | void *addr = NULL; | |
213 | ||
214 | err = -EINVAL; | |
ba180fd4 | 215 | if (bytecount != sizeof(ldt_info)) |
858259cf BS |
216 | goto out; |
217 | err = -EFAULT; | |
ba180fd4 | 218 | if (copy_from_user(&ldt_info, ptr, sizeof(ldt_info))) |
858259cf BS |
219 | goto out; |
220 | ||
221 | err = -EINVAL; | |
ba180fd4 | 222 | if (ldt_info.entry_number >= LDT_ENTRIES) |
858259cf | 223 | goto out; |
ba180fd4 | 224 | if (ldt_info.contents == 3) { |
858259cf BS |
225 | if (func == 1) |
226 | goto out; | |
227 | if (ldt_info.seg_not_present == 0) | |
228 | goto out; | |
229 | } | |
230 | ||
ba180fd4 | 231 | if (!ptrace_ldt) |
01ac835f | 232 | mutex_lock(&ldt->lock); |
858259cf BS |
233 | |
234 | err = write_ldt_entry(mm_idp, func, &ldt_info, &addr, 1); | |
ba180fd4 | 235 | if (err) |
858259cf | 236 | goto out_unlock; |
ba180fd4 JD |
237 | else if (ptrace_ldt) { |
238 | /* With PTRACE_LDT available, this is used as a flag only */ | |
239 | ldt->entry_count = 1; | |
240 | goto out; | |
241 | } | |
242 | ||
243 | if (ldt_info.entry_number >= ldt->entry_count && | |
244 | ldt_info.entry_number >= LDT_DIRECT_ENTRIES) { | |
245 | for (i=ldt->entry_count/LDT_ENTRIES_PER_PAGE; | |
246 | i*LDT_ENTRIES_PER_PAGE <= ldt_info.entry_number; | |
247 | i++) { | |
248 | if (i == 0) | |
e23181de JD |
249 | memcpy(&entry0, ldt->u.entries, |
250 | sizeof(entry0)); | |
251 | ldt->u.pages[i] = (struct ldt_entry *) | |
252 | __get_free_page(GFP_KERNEL|__GFP_ZERO); | |
ba180fd4 | 253 | if (!ldt->u.pages[i]) { |
858259cf BS |
254 | err = -ENOMEM; |
255 | /* Undo the change in host */ | |
256 | memset(&ldt_info, 0, sizeof(ldt_info)); | |
257 | write_ldt_entry(mm_idp, 1, &ldt_info, &addr, 1); | |
258 | goto out_unlock; | |
259 | } | |
ba180fd4 | 260 | if (i == 0) { |
e23181de JD |
261 | memcpy(ldt->u.pages[0], &entry0, |
262 | sizeof(entry0)); | |
263 | memcpy(ldt->u.pages[0]+1, ldt->u.entries+1, | |
858259cf BS |
264 | sizeof(entry0)*(LDT_DIRECT_ENTRIES-1)); |
265 | } | |
266 | ldt->entry_count = (i + 1) * LDT_ENTRIES_PER_PAGE; | |
267 | } | |
268 | } | |
ba180fd4 | 269 | if (ldt->entry_count <= ldt_info.entry_number) |
858259cf BS |
270 | ldt->entry_count = ldt_info.entry_number + 1; |
271 | ||
ba180fd4 | 272 | if (ldt->entry_count <= LDT_DIRECT_ENTRIES) |
e23181de | 273 | ldt_p = ldt->u.entries + ldt_info.entry_number; |
858259cf | 274 | else |
e23181de | 275 | ldt_p = ldt->u.pages[ldt_info.entry_number/LDT_ENTRIES_PER_PAGE] + |
858259cf BS |
276 | ldt_info.entry_number%LDT_ENTRIES_PER_PAGE; |
277 | ||
ba180fd4 JD |
278 | if (ldt_info.base_addr == 0 && ldt_info.limit == 0 && |
279 | (func == 1 || LDT_empty(&ldt_info))) { | |
858259cf BS |
280 | ldt_p->a = 0; |
281 | ldt_p->b = 0; | |
282 | } | |
283 | else{ | |
284 | if (func == 1) | |
285 | ldt_info.useable = 0; | |
286 | ldt_p->a = LDT_entry_a(&ldt_info); | |
287 | ldt_p->b = LDT_entry_b(&ldt_info); | |
288 | } | |
289 | err = 0; | |
290 | ||
291 | out_unlock: | |
01ac835f | 292 | mutex_unlock(&ldt->lock); |
858259cf BS |
293 | out: |
294 | return err; | |
295 | } | |
296 | ||
297 | static long do_modify_ldt_skas(int func, void __user *ptr, | |
298 | unsigned long bytecount) | |
299 | { | |
300 | int ret = -ENOSYS; | |
301 | ||
302 | switch (func) { | |
303 | case 0: | |
304 | ret = read_ldt(ptr, bytecount); | |
305 | break; | |
306 | case 1: | |
307 | case 0x11: | |
308 | ret = write_ldt(ptr, bytecount, func); | |
309 | break; | |
310 | case 2: | |
311 | ret = read_default_ldt(ptr, bytecount); | |
312 | break; | |
313 | } | |
314 | return ret; | |
315 | } | |
316 | ||
af727902 JD |
317 | static DEFINE_SPINLOCK(host_ldt_lock); |
318 | static short dummy_list[9] = {0, -1}; | |
319 | static short * host_ldt_entries = NULL; | |
858259cf | 320 | |
af727902 | 321 | static void ldt_get_host_info(void) |
858259cf BS |
322 | { |
323 | long ret; | |
622e6969 JD |
324 | struct ldt_entry * ldt; |
325 | short *tmp; | |
858259cf BS |
326 | int i, size, k, order; |
327 | ||
af727902 JD |
328 | spin_lock(&host_ldt_lock); |
329 | ||
ba180fd4 | 330 | if (host_ldt_entries != NULL) { |
af727902 JD |
331 | spin_unlock(&host_ldt_lock); |
332 | return; | |
333 | } | |
858259cf BS |
334 | host_ldt_entries = dummy_list+1; |
335 | ||
af727902 JD |
336 | spin_unlock(&host_ldt_lock); |
337 | ||
ba180fd4 JD |
338 | for (i = LDT_PAGES_MAX-1, order=0; i; i>>=1, order++) |
339 | ; | |
858259cf BS |
340 | |
341 | ldt = (struct ldt_entry *) | |
342 | __get_free_pages(GFP_KERNEL|__GFP_ZERO, order); | |
ba180fd4 JD |
343 | if (ldt == NULL) { |
344 | printk(KERN_ERR "ldt_get_host_info: couldn't allocate buffer " | |
345 | "for host ldt\n"); | |
858259cf BS |
346 | return; |
347 | } | |
348 | ||
349 | ret = modify_ldt(0, ldt, (1<<order)*PAGE_SIZE); | |
ba180fd4 JD |
350 | if (ret < 0) { |
351 | printk(KERN_ERR "ldt_get_host_info: couldn't read host ldt\n"); | |
858259cf BS |
352 | goto out_free; |
353 | } | |
ba180fd4 | 354 | if (ret == 0) { |
858259cf BS |
355 | /* default_ldt is active, simply write an empty entry 0 */ |
356 | host_ldt_entries = dummy_list; | |
357 | goto out_free; | |
358 | } | |
359 | ||
ba180fd4 JD |
360 | for (i=0, size=0; i<ret/LDT_ENTRY_SIZE; i++) { |
361 | if (ldt[i].a != 0 || ldt[i].b != 0) | |
858259cf BS |
362 | size++; |
363 | } | |
364 | ||
ba180fd4 | 365 | if (size < ARRAY_SIZE(dummy_list)) |
858259cf | 366 | host_ldt_entries = dummy_list; |
858259cf BS |
367 | else { |
368 | size = (size + 1) * sizeof(dummy_list[0]); | |
af727902 | 369 | tmp = kmalloc(size, GFP_KERNEL); |
ba180fd4 JD |
370 | if (tmp == NULL) { |
371 | printk(KERN_ERR "ldt_get_host_info: couldn't allocate " | |
372 | "host ldt list\n"); | |
858259cf BS |
373 | goto out_free; |
374 | } | |
af727902 | 375 | host_ldt_entries = tmp; |
858259cf BS |
376 | } |
377 | ||
ba180fd4 JD |
378 | for (i=0, k=0; i<ret/LDT_ENTRY_SIZE; i++) { |
379 | if (ldt[i].a != 0 || ldt[i].b != 0) | |
858259cf | 380 | host_ldt_entries[k++] = i; |
858259cf BS |
381 | } |
382 | host_ldt_entries[k] = -1; | |
383 | ||
384 | out_free: | |
385 | free_pages((unsigned long)ldt, order); | |
386 | } | |
387 | ||
6c738ffa | 388 | long init_new_ldt(struct mm_context *new_mm, struct mm_context *from_mm) |
858259cf BS |
389 | { |
390 | struct user_desc desc; | |
391 | short * num_p; | |
392 | int i; | |
393 | long page, err=0; | |
394 | void *addr = NULL; | |
12919aa6 | 395 | struct proc_mm_op copy; |
858259cf | 396 | |
858259cf | 397 | |
ba180fd4 | 398 | if (!ptrace_ldt) |
01ac835f | 399 | mutex_init(&new_mm->ldt.lock); |
858259cf | 400 | |
ba180fd4 | 401 | if (!from_mm) { |
12919aa6 | 402 | memset(&desc, 0, sizeof(desc)); |
858259cf BS |
403 | /* |
404 | * We have to initialize a clean ldt. | |
405 | */ | |
ba180fd4 | 406 | if (proc_mm) { |
858259cf BS |
407 | /* |
408 | * If the new mm was created using proc_mm, host's | |
409 | * default-ldt currently is assigned, which normally | |
410 | * contains the call-gates for lcall7 and lcall27. | |
411 | * To remove these gates, we simply write an empty | |
412 | * entry as number 0 to the host. | |
413 | */ | |
ba180fd4 | 414 | err = write_ldt_entry(&new_mm->id, 1, &desc, &addr, 1); |
858259cf BS |
415 | } |
416 | else{ | |
417 | /* | |
418 | * Now we try to retrieve info about the ldt, we | |
419 | * inherited from the host. All ldt-entries found | |
420 | * will be reset in the following loop | |
421 | */ | |
af727902 | 422 | ldt_get_host_info(); |
ba180fd4 | 423 | for (num_p=host_ldt_entries; *num_p != -1; num_p++) { |
858259cf BS |
424 | desc.entry_number = *num_p; |
425 | err = write_ldt_entry(&new_mm->id, 1, &desc, | |
426 | &addr, *(num_p + 1) == -1); | |
ba180fd4 | 427 | if (err) |
858259cf BS |
428 | break; |
429 | } | |
430 | } | |
431 | new_mm->ldt.entry_count = 0; | |
12919aa6 BS |
432 | |
433 | goto out; | |
858259cf | 434 | } |
12919aa6 | 435 | |
ba180fd4 JD |
436 | if (proc_mm) { |
437 | /* | |
438 | * We have a valid from_mm, so we now have to copy the LDT of | |
12919aa6 BS |
439 | * from_mm to new_mm, because using proc_mm an new mm with |
440 | * an empty/default LDT was created in new_mm() | |
441 | */ | |
442 | copy = ((struct proc_mm_op) { .op = MM_COPY_SEGMENTS, | |
443 | .u = | |
444 | { .copy_segments = | |
445 | from_mm->id.u.mm_fd } } ); | |
a6ea4cce | 446 | i = os_write_file(new_mm->id.u.mm_fd, ©, sizeof(copy)); |
ba180fd4 JD |
447 | if (i != sizeof(copy)) |
448 | printk(KERN_ERR "new_mm : /proc/mm copy_segments " | |
449 | "failed, err = %d\n", -i); | |
12919aa6 BS |
450 | } |
451 | ||
ba180fd4 JD |
452 | if (!ptrace_ldt) { |
453 | /* | |
454 | * Our local LDT is used to supply the data for | |
858259cf BS |
455 | * modify_ldt(READLDT), if PTRACE_LDT isn't available, |
456 | * i.e., we have to use the stub for modify_ldt, which | |
457 | * can't handle the big read buffer of up to 64kB. | |
458 | */ | |
01ac835f | 459 | mutex_lock(&from_mm->ldt.lock); |
ba180fd4 | 460 | if (from_mm->ldt.entry_count <= LDT_DIRECT_ENTRIES) |
e23181de JD |
461 | memcpy(new_mm->ldt.u.entries, from_mm->ldt.u.entries, |
462 | sizeof(new_mm->ldt.u.entries)); | |
ba180fd4 | 463 | else { |
858259cf | 464 | i = from_mm->ldt.entry_count / LDT_ENTRIES_PER_PAGE; |
ba180fd4 | 465 | while (i-->0) { |
858259cf | 466 | page = __get_free_page(GFP_KERNEL|__GFP_ZERO); |
ba180fd4 | 467 | if (!page) { |
858259cf BS |
468 | err = -ENOMEM; |
469 | break; | |
470 | } | |
e23181de JD |
471 | new_mm->ldt.u.pages[i] = |
472 | (struct ldt_entry *) page; | |
473 | memcpy(new_mm->ldt.u.pages[i], | |
474 | from_mm->ldt.u.pages[i], PAGE_SIZE); | |
858259cf BS |
475 | } |
476 | } | |
477 | new_mm->ldt.entry_count = from_mm->ldt.entry_count; | |
01ac835f | 478 | mutex_unlock(&from_mm->ldt.lock); |
858259cf BS |
479 | } |
480 | ||
12919aa6 | 481 | out: |
858259cf BS |
482 | return err; |
483 | } | |
484 | ||
485 | ||
6c738ffa | 486 | void free_ldt(struct mm_context *mm) |
858259cf BS |
487 | { |
488 | int i; | |
489 | ||
ba180fd4 | 490 | if (!ptrace_ldt && mm->ldt.entry_count > LDT_DIRECT_ENTRIES) { |
858259cf | 491 | i = mm->ldt.entry_count / LDT_ENTRIES_PER_PAGE; |
ba180fd4 JD |
492 | while (i-- > 0) |
493 | free_page((long) mm->ldt.u.pages[i]); | |
858259cf BS |
494 | } |
495 | mm->ldt.entry_count = 0; | |
496 | } | |
858259cf BS |
497 | |
498 | int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount) | |
499 | { | |
6aa802ce | 500 | return do_modify_ldt_skas(func, ptr, bytecount); |
858259cf | 501 | } |