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6#include <linux/mm.h>
7#include <linux/sched.h>
8#include <linux/slab.h>
9#include <linux/uaccess.h>
10#include <asm/unistd.h>
11#include <os.h>
12#include <skas.h>
13#include <sysdep/tls.h>
14
15static inline int modify_ldt (int func, void *ptr, unsigned long bytecount)
16{
17 return syscall(__NR_modify_ldt, func, ptr, bytecount);
18}
19
20static long write_ldt_entry(struct mm_id *mm_idp, int func,
21 struct user_desc *desc, void **addr, int done)
22{
23 long res;
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);
36 }
37
38 return res;
39}
40
41
42
43
44
45
46
47
48
49
50
51
52
53static int read_ldt(void __user * ptr, unsigned long bytecount)
54{
55 int i, err = 0;
56 unsigned long size;
57 uml_ldt_t *ldt = ¤t->mm->context.arch.ldt;
58
59 if (!ldt->entry_count)
60 goto out;
61 if (bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES)
62 bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES;
63 err = bytecount;
64
65 mutex_lock(&ldt->lock);
66 if (ldt->entry_count <= LDT_DIRECT_ENTRIES) {
67 size = LDT_ENTRY_SIZE*LDT_DIRECT_ENTRIES;
68 if (size > bytecount)
69 size = bytecount;
70 if (copy_to_user(ptr, ldt->u.entries, size))
71 err = -EFAULT;
72 bytecount -= size;
73 ptr += size;
74 }
75 else {
76 for (i=0; i<ldt->entry_count/LDT_ENTRIES_PER_PAGE && bytecount;
77 i++) {
78 size = PAGE_SIZE;
79 if (size > bytecount)
80 size = bytecount;
81 if (copy_to_user(ptr, ldt->u.pages[i], size)) {
82 err = -EFAULT;
83 break;
84 }
85 bytecount -= size;
86 ptr += size;
87 }
88 }
89 mutex_unlock(&ldt->lock);
90
91 if (bytecount == 0 || err == -EFAULT)
92 goto out;
93
94 if (clear_user(ptr, bytecount))
95 err = -EFAULT;
96
97out:
98 return err;
99}
100
101static int read_default_ldt(void __user * ptr, unsigned long bytecount)
102{
103 int err;
104
105 if (bytecount > 5*LDT_ENTRY_SIZE)
106 bytecount = 5*LDT_ENTRY_SIZE;
107
108 err = bytecount;
109
110
111
112
113
114 if (clear_user(ptr, bytecount))
115 err = -EFAULT;
116
117 return err;
118}
119
120static int write_ldt(void __user * ptr, unsigned long bytecount, int func)
121{
122 uml_ldt_t *ldt = ¤t->mm->context.arch.ldt;
123 struct mm_id * mm_idp = ¤t->mm->context.id;
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;
130 if (bytecount != sizeof(ldt_info))
131 goto out;
132 err = -EFAULT;
133 if (copy_from_user(&ldt_info, ptr, sizeof(ldt_info)))
134 goto out;
135
136 err = -EINVAL;
137 if (ldt_info.entry_number >= LDT_ENTRIES)
138 goto out;
139 if (ldt_info.contents == 3) {
140 if (func == 1)
141 goto out;
142 if (ldt_info.seg_not_present == 0)
143 goto out;
144 }
145
146 mutex_lock(&ldt->lock);
147
148 err = write_ldt_entry(mm_idp, func, &ldt_info, &addr, 1);
149 if (err)
150 goto out_unlock;
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)
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);
162 if (!ldt->u.pages[i]) {
163 err = -ENOMEM;
164
165 memset(&ldt_info, 0, sizeof(ldt_info));
166 write_ldt_entry(mm_idp, 1, &ldt_info, &addr, 1);
167 goto out_unlock;
168 }
169 if (i == 0) {
170 memcpy(ldt->u.pages[0], &entry0,
171 sizeof(entry0));
172 memcpy(ldt->u.pages[0]+1, ldt->u.entries+1,
173 sizeof(entry0)*(LDT_DIRECT_ENTRIES-1));
174 }
175 ldt->entry_count = (i + 1) * LDT_ENTRIES_PER_PAGE;
176 }
177 }
178 if (ldt->entry_count <= ldt_info.entry_number)
179 ldt->entry_count = ldt_info.entry_number + 1;
180
181 if (ldt->entry_count <= LDT_DIRECT_ENTRIES)
182 ldt_p = ldt->u.entries + ldt_info.entry_number;
183 else
184 ldt_p = ldt->u.pages[ldt_info.entry_number/LDT_ENTRIES_PER_PAGE] +
185 ldt_info.entry_number%LDT_ENTRIES_PER_PAGE;
186
187 if (ldt_info.base_addr == 0 && ldt_info.limit == 0 &&
188 (func == 1 || LDT_empty(&ldt_info))) {
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
200out_unlock:
201 mutex_unlock(&ldt->lock);
202out:
203 return err;
204}
205
206static 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
226static DEFINE_SPINLOCK(host_ldt_lock);
227static short dummy_list[9] = {0, -1};
228static short * host_ldt_entries = NULL;
229
230static void ldt_get_host_info(void)
231{
232 long ret;
233 struct ldt_entry * ldt;
234 short *tmp;
235 int i, size, k, order;
236
237 spin_lock(&host_ldt_lock);
238
239 if (host_ldt_entries != NULL) {
240 spin_unlock(&host_ldt_lock);
241 return;
242 }
243 host_ldt_entries = dummy_list+1;
244
245 spin_unlock(&host_ldt_lock);
246
247 for (i = LDT_PAGES_MAX-1, order=0; i; i>>=1, order++)
248 ;
249
250 ldt = (struct ldt_entry *)
251 __get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
252 if (ldt == NULL) {
253 printk(KERN_ERR "ldt_get_host_info: couldn't allocate buffer "
254 "for host ldt\n");
255 return;
256 }
257
258 ret = modify_ldt(0, ldt, (1<<order)*PAGE_SIZE);
259 if (ret < 0) {
260 printk(KERN_ERR "ldt_get_host_info: couldn't read host ldt\n");
261 goto out_free;
262 }
263 if (ret == 0) {
264
265 host_ldt_entries = dummy_list;
266 goto out_free;
267 }
268
269 for (i=0, size=0; i<ret/LDT_ENTRY_SIZE; i++) {
270 if (ldt[i].a != 0 || ldt[i].b != 0)
271 size++;
272 }
273
274 if (size < ARRAY_SIZE(dummy_list))
275 host_ldt_entries = dummy_list;
276 else {
277 size = (size + 1) * sizeof(dummy_list[0]);
278 tmp = kmalloc(size, GFP_KERNEL);
279 if (tmp == NULL) {
280 printk(KERN_ERR "ldt_get_host_info: couldn't allocate "
281 "host ldt list\n");
282 goto out_free;
283 }
284 host_ldt_entries = tmp;
285 }
286
287 for (i=0, k=0; i<ret/LDT_ENTRY_SIZE; i++) {
288 if (ldt[i].a != 0 || ldt[i].b != 0)
289 host_ldt_entries[k++] = i;
290 }
291 host_ldt_entries[k] = -1;
292
293out_free:
294 free_pages((unsigned long)ldt, order);
295}
296
297long init_new_ldt(struct mm_context *new_mm, struct mm_context *from_mm)
298{
299 struct user_desc desc;
300 short * num_p;
301 int i;
302 long page, err=0;
303 void *addr = NULL;
304
305
306 mutex_init(&new_mm->arch.ldt.lock);
307
308 if (!from_mm) {
309 memset(&desc, 0, sizeof(desc));
310
311
312
313
314
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;
322 }
323 new_mm->arch.ldt.entry_count = 0;
324
325 goto out;
326 }
327
328
329
330
331
332
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;
345 }
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);
350 }
351 }
352 new_mm->arch.ldt.entry_count = from_mm->arch.ldt.entry_count;
353 mutex_unlock(&from_mm->arch.ldt.lock);
354
355 out:
356 return err;
357}
358
359
360void free_ldt(struct mm_context *mm)
361{
362 int i;
363
364 if (mm->arch.ldt.entry_count > LDT_DIRECT_ENTRIES) {
365 i = mm->arch.ldt.entry_count / LDT_ENTRIES_PER_PAGE;
366 while (i-- > 0)
367 free_page((long) mm->arch.ldt.u.pages[i]);
368 }
369 mm->arch.ldt.entry_count = 0;
370}
371
372int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
373{
374 return do_modify_ldt_skas(func, ptr, bytecount);
375}
376
