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> | |
5a0e3ad6 | 8 | #include <linux/slab.h> |
1d04c8d7 | 9 | #include <linux/uaccess.h> |
8192ab42 | 10 | #include <asm/unistd.h> |
37185b33 | 11 | #include <os.h> |
37185b33 | 12 | #include <skas.h> |
37185b33 | 13 | #include <sysdep/tls.h> |
ba180fd4 | 14 | |
37e81a01 HWH |
15 | static inline int modify_ldt (int func, void *ptr, unsigned long bytecount) |
16 | { | |
17 | return syscall(__NR_modify_ldt, func, ptr, bytecount); | |
18 | } | |
858259cf | 19 | |
99764fa4 WC |
20 | static long write_ldt_entry(struct mm_id *mm_idp, int func, |
21 | struct user_desc *desc, void **addr, int done) | |
858259cf BS |
22 | { |
23 | long res; | |
d0b5e15f RW |
24 | void *stub_addr; |
25 | res = syscall_stub_data(mm_idp, (unsigned long *)desc, | |
26 | (sizeof(*desc) + sizeof(long) - 1) & | |
27 | ~(sizeof(long) - 1), | |
28 | addr, &stub_addr); | |
29 | if (!res) { | |
30 | unsigned long args[] = { func, | |
31 | (unsigned long)stub_addr, | |
32 | sizeof(*desc), | |
33 | 0, 0, 0 }; | |
34 | res = run_syscall_stub(mm_idp, __NR_modify_ldt, args, | |
35 | 0, addr, done); | |
858259cf BS |
36 | } |
37 | ||
858259cf BS |
38 | return res; |
39 | } | |
40 | ||
41 | /* | |
42 | * In skas mode, we hold our own ldt data in UML. | |
43 | * Thus, the code implementing sys_modify_ldt_skas | |
44 | * is very similar to (and mostly stolen from) sys_modify_ldt | |
45 | * for arch/i386/kernel/ldt.c | |
46 | * The routines copied and modified in part are: | |
47 | * - read_ldt | |
48 | * - read_default_ldt | |
49 | * - write_ldt | |
50 | * - sys_modify_ldt_skas | |
51 | */ | |
52 | ||
53 | static int read_ldt(void __user * ptr, unsigned long bytecount) | |
54 | { | |
55 | int i, err = 0; | |
56 | unsigned long size; | |
b3ee571e | 57 | uml_ldt_t *ldt = ¤t->mm->context.arch.ldt; |
858259cf | 58 | |
ba180fd4 | 59 | if (!ldt->entry_count) |
858259cf | 60 | goto out; |
ba180fd4 | 61 | if (bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES) |
858259cf BS |
62 | bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES; |
63 | err = bytecount; | |
64 | ||
01ac835f | 65 | mutex_lock(&ldt->lock); |
ba180fd4 | 66 | if (ldt->entry_count <= LDT_DIRECT_ENTRIES) { |
858259cf | 67 | size = LDT_ENTRY_SIZE*LDT_DIRECT_ENTRIES; |
ba180fd4 | 68 | if (size > bytecount) |
858259cf | 69 | size = bytecount; |
ba180fd4 | 70 | if (copy_to_user(ptr, ldt->u.entries, size)) |
858259cf BS |
71 | err = -EFAULT; |
72 | bytecount -= size; | |
73 | ptr += size; | |
74 | } | |
75 | else { | |
ba180fd4 JD |
76 | for (i=0; i<ldt->entry_count/LDT_ENTRIES_PER_PAGE && bytecount; |
77 | i++) { | |
858259cf | 78 | size = PAGE_SIZE; |
ba180fd4 | 79 | if (size > bytecount) |
858259cf | 80 | size = bytecount; |
ba180fd4 | 81 | if (copy_to_user(ptr, ldt->u.pages[i], size)) { |
858259cf BS |
82 | err = -EFAULT; |
83 | break; | |
84 | } | |
85 | bytecount -= size; | |
86 | ptr += size; | |
87 | } | |
88 | } | |
01ac835f | 89 | mutex_unlock(&ldt->lock); |
858259cf | 90 | |
ba180fd4 | 91 | if (bytecount == 0 || err == -EFAULT) |
858259cf BS |
92 | goto out; |
93 | ||
ba180fd4 | 94 | if (clear_user(ptr, bytecount)) |
858259cf BS |
95 | err = -EFAULT; |
96 | ||
97 | out: | |
98 | return err; | |
99 | } | |
100 | ||
101 | static int read_default_ldt(void __user * ptr, unsigned long bytecount) | |
102 | { | |
103 | int err; | |
104 | ||
ba180fd4 | 105 | if (bytecount > 5*LDT_ENTRY_SIZE) |
858259cf BS |
106 | bytecount = 5*LDT_ENTRY_SIZE; |
107 | ||
108 | err = bytecount; | |
ba180fd4 JD |
109 | /* |
110 | * UML doesn't support lcall7 and lcall27. | |
858259cf BS |
111 | * So, we don't really have a default ldt, but emulate |
112 | * an empty ldt of common host default ldt size. | |
113 | */ | |
ba180fd4 | 114 | if (clear_user(ptr, bytecount)) |
858259cf BS |
115 | err = -EFAULT; |
116 | ||
117 | return err; | |
118 | } | |
119 | ||
120 | static int write_ldt(void __user * ptr, unsigned long bytecount, int func) | |
121 | { | |
b3ee571e | 122 | uml_ldt_t *ldt = ¤t->mm->context.arch.ldt; |
6c738ffa | 123 | struct mm_id * mm_idp = ¤t->mm->context.id; |
858259cf BS |
124 | int i, err; |
125 | struct user_desc ldt_info; | |
126 | struct ldt_entry entry0, *ldt_p; | |
127 | void *addr = NULL; | |
128 | ||
129 | err = -EINVAL; | |
ba180fd4 | 130 | if (bytecount != sizeof(ldt_info)) |
858259cf BS |
131 | goto out; |
132 | err = -EFAULT; | |
ba180fd4 | 133 | if (copy_from_user(&ldt_info, ptr, sizeof(ldt_info))) |
858259cf BS |
134 | goto out; |
135 | ||
136 | err = -EINVAL; | |
ba180fd4 | 137 | if (ldt_info.entry_number >= LDT_ENTRIES) |
858259cf | 138 | goto out; |
ba180fd4 | 139 | if (ldt_info.contents == 3) { |
858259cf BS |
140 | if (func == 1) |
141 | goto out; | |
142 | if (ldt_info.seg_not_present == 0) | |
143 | goto out; | |
144 | } | |
145 | ||
d0b5e15f | 146 | mutex_lock(&ldt->lock); |
858259cf BS |
147 | |
148 | err = write_ldt_entry(mm_idp, func, &ldt_info, &addr, 1); | |
ba180fd4 | 149 | if (err) |
858259cf | 150 | goto out_unlock; |
ba180fd4 JD |
151 | |
152 | if (ldt_info.entry_number >= ldt->entry_count && | |
153 | ldt_info.entry_number >= LDT_DIRECT_ENTRIES) { | |
154 | for (i=ldt->entry_count/LDT_ENTRIES_PER_PAGE; | |
155 | i*LDT_ENTRIES_PER_PAGE <= ldt_info.entry_number; | |
156 | i++) { | |
157 | if (i == 0) | |
e23181de JD |
158 | memcpy(&entry0, ldt->u.entries, |
159 | sizeof(entry0)); | |
160 | ldt->u.pages[i] = (struct ldt_entry *) | |
161 | __get_free_page(GFP_KERNEL|__GFP_ZERO); | |
ba180fd4 | 162 | if (!ldt->u.pages[i]) { |
858259cf BS |
163 | err = -ENOMEM; |
164 | /* Undo the change in host */ | |
165 | memset(&ldt_info, 0, sizeof(ldt_info)); | |
166 | write_ldt_entry(mm_idp, 1, &ldt_info, &addr, 1); | |
167 | goto out_unlock; | |
168 | } | |
ba180fd4 | 169 | if (i == 0) { |
e23181de JD |
170 | memcpy(ldt->u.pages[0], &entry0, |
171 | sizeof(entry0)); | |
172 | memcpy(ldt->u.pages[0]+1, ldt->u.entries+1, | |
858259cf BS |
173 | sizeof(entry0)*(LDT_DIRECT_ENTRIES-1)); |
174 | } | |
175 | ldt->entry_count = (i + 1) * LDT_ENTRIES_PER_PAGE; | |
176 | } | |
177 | } | |
ba180fd4 | 178 | if (ldt->entry_count <= ldt_info.entry_number) |
858259cf BS |
179 | ldt->entry_count = ldt_info.entry_number + 1; |
180 | ||
ba180fd4 | 181 | if (ldt->entry_count <= LDT_DIRECT_ENTRIES) |
e23181de | 182 | ldt_p = ldt->u.entries + ldt_info.entry_number; |
858259cf | 183 | else |
e23181de | 184 | ldt_p = ldt->u.pages[ldt_info.entry_number/LDT_ENTRIES_PER_PAGE] + |
858259cf BS |
185 | ldt_info.entry_number%LDT_ENTRIES_PER_PAGE; |
186 | ||
ba180fd4 JD |
187 | if (ldt_info.base_addr == 0 && ldt_info.limit == 0 && |
188 | (func == 1 || LDT_empty(&ldt_info))) { | |
858259cf BS |
189 | ldt_p->a = 0; |
190 | ldt_p->b = 0; | |
191 | } | |
192 | else{ | |
193 | if (func == 1) | |
194 | ldt_info.useable = 0; | |
195 | ldt_p->a = LDT_entry_a(&ldt_info); | |
196 | ldt_p->b = LDT_entry_b(&ldt_info); | |
197 | } | |
198 | err = 0; | |
199 | ||
200 | out_unlock: | |
01ac835f | 201 | mutex_unlock(&ldt->lock); |
858259cf BS |
202 | out: |
203 | return err; | |
204 | } | |
205 | ||
206 | static long do_modify_ldt_skas(int func, void __user *ptr, | |
207 | unsigned long bytecount) | |
208 | { | |
209 | int ret = -ENOSYS; | |
210 | ||
211 | switch (func) { | |
212 | case 0: | |
213 | ret = read_ldt(ptr, bytecount); | |
214 | break; | |
215 | case 1: | |
216 | case 0x11: | |
217 | ret = write_ldt(ptr, bytecount, func); | |
218 | break; | |
219 | case 2: | |
220 | ret = read_default_ldt(ptr, bytecount); | |
221 | break; | |
222 | } | |
223 | return ret; | |
224 | } | |
225 | ||
af727902 JD |
226 | static DEFINE_SPINLOCK(host_ldt_lock); |
227 | static short dummy_list[9] = {0, -1}; | |
228 | static short * host_ldt_entries = NULL; | |
858259cf | 229 | |
af727902 | 230 | static void ldt_get_host_info(void) |
858259cf BS |
231 | { |
232 | long ret; | |
622e6969 JD |
233 | struct ldt_entry * ldt; |
234 | short *tmp; | |
858259cf BS |
235 | int i, size, k, order; |
236 | ||
af727902 JD |
237 | spin_lock(&host_ldt_lock); |
238 | ||
ba180fd4 | 239 | if (host_ldt_entries != NULL) { |
af727902 JD |
240 | spin_unlock(&host_ldt_lock); |
241 | return; | |
242 | } | |
858259cf BS |
243 | host_ldt_entries = dummy_list+1; |
244 | ||
af727902 JD |
245 | spin_unlock(&host_ldt_lock); |
246 | ||
ba180fd4 JD |
247 | for (i = LDT_PAGES_MAX-1, order=0; i; i>>=1, order++) |
248 | ; | |
858259cf BS |
249 | |
250 | ldt = (struct ldt_entry *) | |
251 | __get_free_pages(GFP_KERNEL|__GFP_ZERO, order); | |
ba180fd4 JD |
252 | if (ldt == NULL) { |
253 | printk(KERN_ERR "ldt_get_host_info: couldn't allocate buffer " | |
254 | "for host ldt\n"); | |
858259cf BS |
255 | return; |
256 | } | |
257 | ||
258 | ret = modify_ldt(0, ldt, (1<<order)*PAGE_SIZE); | |
ba180fd4 JD |
259 | if (ret < 0) { |
260 | printk(KERN_ERR "ldt_get_host_info: couldn't read host ldt\n"); | |
858259cf BS |
261 | goto out_free; |
262 | } | |
ba180fd4 | 263 | if (ret == 0) { |
858259cf BS |
264 | /* default_ldt is active, simply write an empty entry 0 */ |
265 | host_ldt_entries = dummy_list; | |
266 | goto out_free; | |
267 | } | |
268 | ||
ba180fd4 JD |
269 | for (i=0, size=0; i<ret/LDT_ENTRY_SIZE; i++) { |
270 | if (ldt[i].a != 0 || ldt[i].b != 0) | |
858259cf BS |
271 | size++; |
272 | } | |
273 | ||
ba180fd4 | 274 | if (size < ARRAY_SIZE(dummy_list)) |
858259cf | 275 | host_ldt_entries = dummy_list; |
858259cf BS |
276 | else { |
277 | size = (size + 1) * sizeof(dummy_list[0]); | |
af727902 | 278 | tmp = kmalloc(size, GFP_KERNEL); |
ba180fd4 JD |
279 | if (tmp == NULL) { |
280 | printk(KERN_ERR "ldt_get_host_info: couldn't allocate " | |
281 | "host ldt list\n"); | |
858259cf BS |
282 | goto out_free; |
283 | } | |
af727902 | 284 | host_ldt_entries = tmp; |
858259cf BS |
285 | } |
286 | ||
ba180fd4 JD |
287 | for (i=0, k=0; i<ret/LDT_ENTRY_SIZE; i++) { |
288 | if (ldt[i].a != 0 || ldt[i].b != 0) | |
858259cf | 289 | host_ldt_entries[k++] = i; |
858259cf BS |
290 | } |
291 | host_ldt_entries[k] = -1; | |
292 | ||
293 | out_free: | |
294 | free_pages((unsigned long)ldt, order); | |
295 | } | |
296 | ||
6c738ffa | 297 | long init_new_ldt(struct mm_context *new_mm, struct mm_context *from_mm) |
858259cf BS |
298 | { |
299 | struct user_desc desc; | |
300 | short * num_p; | |
301 | int i; | |
302 | long page, err=0; | |
303 | void *addr = NULL; | |
304 | ||
858259cf | 305 | |
d0b5e15f | 306 | mutex_init(&new_mm->arch.ldt.lock); |
858259cf | 307 | |
ba180fd4 | 308 | if (!from_mm) { |
12919aa6 | 309 | memset(&desc, 0, sizeof(desc)); |
858259cf | 310 | /* |
d0b5e15f RW |
311 | * Now we try to retrieve info about the ldt, we |
312 | * inherited from the host. All ldt-entries found | |
313 | * will be reset in the following loop | |
858259cf | 314 | */ |
d0b5e15f RW |
315 | ldt_get_host_info(); |
316 | for (num_p=host_ldt_entries; *num_p != -1; num_p++) { | |
317 | desc.entry_number = *num_p; | |
318 | err = write_ldt_entry(&new_mm->id, 1, &desc, | |
319 | &addr, *(num_p + 1) == -1); | |
320 | if (err) | |
321 | break; | |
858259cf | 322 | } |
b3ee571e | 323 | new_mm->arch.ldt.entry_count = 0; |
12919aa6 BS |
324 | |
325 | goto out; | |
858259cf | 326 | } |
12919aa6 | 327 | |
d0b5e15f RW |
328 | /* |
329 | * Our local LDT is used to supply the data for | |
330 | * modify_ldt(READLDT), if PTRACE_LDT isn't available, | |
331 | * i.e., we have to use the stub for modify_ldt, which | |
332 | * can't handle the big read buffer of up to 64kB. | |
333 | */ | |
334 | mutex_lock(&from_mm->arch.ldt.lock); | |
335 | if (from_mm->arch.ldt.entry_count <= LDT_DIRECT_ENTRIES) | |
336 | memcpy(new_mm->arch.ldt.u.entries, from_mm->arch.ldt.u.entries, | |
337 | sizeof(new_mm->arch.ldt.u.entries)); | |
338 | else { | |
339 | i = from_mm->arch.ldt.entry_count / LDT_ENTRIES_PER_PAGE; | |
340 | while (i-->0) { | |
341 | page = __get_free_page(GFP_KERNEL|__GFP_ZERO); | |
342 | if (!page) { | |
343 | err = -ENOMEM; | |
344 | break; | |
858259cf | 345 | } |
d0b5e15f RW |
346 | new_mm->arch.ldt.u.pages[i] = |
347 | (struct ldt_entry *) page; | |
348 | memcpy(new_mm->arch.ldt.u.pages[i], | |
349 | from_mm->arch.ldt.u.pages[i], PAGE_SIZE); | |
858259cf | 350 | } |
858259cf | 351 | } |
d0b5e15f RW |
352 | new_mm->arch.ldt.entry_count = from_mm->arch.ldt.entry_count; |
353 | mutex_unlock(&from_mm->arch.ldt.lock); | |
858259cf | 354 | |
12919aa6 | 355 | out: |
858259cf BS |
356 | return err; |
357 | } | |
358 | ||
359 | ||
6c738ffa | 360 | void free_ldt(struct mm_context *mm) |
858259cf BS |
361 | { |
362 | int i; | |
363 | ||
d0b5e15f | 364 | if (mm->arch.ldt.entry_count > LDT_DIRECT_ENTRIES) { |
b3ee571e | 365 | i = mm->arch.ldt.entry_count / LDT_ENTRIES_PER_PAGE; |
ba180fd4 | 366 | while (i-- > 0) |
b3ee571e | 367 | free_page((long) mm->arch.ldt.u.pages[i]); |
858259cf | 368 | } |
b3ee571e | 369 | mm->arch.ldt.entry_count = 0; |
858259cf | 370 | } |
858259cf BS |
371 | |
372 | int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount) | |
373 | { | |
6aa802ce | 374 | return do_modify_ldt_skas(func, ptr, bytecount); |
858259cf | 375 | } |