Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com) |
| 3 | * Licensed under the GPL |
| 4 | */ |
| 5 | |
Bodo Stroesser | 858259c | 2005-11-07 00:58:55 -0800 | [diff] [blame] | 6 | #include "linux/stddef.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | #include "linux/config.h" |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 8 | #include "linux/sched.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | #include "linux/slab.h" |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 10 | #include "linux/types.h" |
Bodo Stroesser | 858259c | 2005-11-07 00:58:55 -0800 | [diff] [blame] | 11 | #include "linux/errno.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include "asm/uaccess.h" |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 13 | #include "asm/smp.h" |
| 14 | #include "asm/ldt.h" |
Bodo Stroesser | 858259c | 2005-11-07 00:58:55 -0800 | [diff] [blame] | 15 | #include "asm/unistd.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | #include "choose-mode.h" |
| 17 | #include "kern.h" |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 18 | #include "mode_kern.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | extern int modify_ldt(int func, void *ptr, unsigned long bytecount); |
| 21 | |
Bodo Stroesser | 858259c | 2005-11-07 00:58:55 -0800 | [diff] [blame] | 22 | #ifdef CONFIG_MODE_TT |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 23 | |
Bodo Stroesser | 858259c | 2005-11-07 00:58:55 -0800 | [diff] [blame] | 24 | static long do_modify_ldt_tt(int func, void __user *ptr, |
| 25 | unsigned long bytecount) |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 26 | { |
| 27 | struct user_desc info; |
| 28 | int res = 0; |
| 29 | void *buf = NULL; |
| 30 | void *p = NULL; /* What we pass to host. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | |
| 32 | switch(func){ |
| 33 | case 1: |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 34 | case 0x11: /* write_ldt */ |
| 35 | /* Do this check now to avoid overflows. */ |
| 36 | if (bytecount != sizeof(struct user_desc)) { |
| 37 | res = -EINVAL; |
| 38 | goto out; |
| 39 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 41 | if(copy_from_user(&info, ptr, sizeof(info))) { |
| 42 | res = -EFAULT; |
| 43 | goto out; |
| 44 | } |
| 45 | |
| 46 | p = &info; |
| 47 | break; |
| 48 | case 0: |
| 49 | case 2: /* read_ldt */ |
| 50 | |
| 51 | /* The use of info avoids kmalloc on the write case, not on the |
| 52 | * read one. */ |
| 53 | buf = kmalloc(bytecount, GFP_KERNEL); |
| 54 | if (!buf) { |
| 55 | res = -ENOMEM; |
| 56 | goto out; |
| 57 | } |
| 58 | p = buf; |
Paolo 'Blaisorblade' Giarrusso | 36decba | 2005-09-21 18:38:57 +0200 | [diff] [blame] | 59 | break; |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 60 | default: |
| 61 | res = -ENOSYS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | goto out; |
| 63 | } |
| 64 | |
Bodo Stroesser | 858259c | 2005-11-07 00:58:55 -0800 | [diff] [blame] | 65 | res = modify_ldt(func, p, bytecount); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | if(res < 0) |
| 67 | goto out; |
| 68 | |
| 69 | switch(func){ |
| 70 | case 0: |
| 71 | case 2: |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 72 | /* Modify_ldt was for reading and returned the number of read |
| 73 | * bytes.*/ |
| 74 | if(copy_to_user(ptr, p, res)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | res = -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 76 | break; |
| 77 | } |
| 78 | |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 79 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | kfree(buf); |
Paolo 'Blaisorblade' Giarrusso | 2e5e559 | 2005-07-14 00:33:37 -0700 | [diff] [blame] | 81 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | } |
Bodo Stroesser | 858259c | 2005-11-07 00:58:55 -0800 | [diff] [blame] | 83 | |
| 84 | #endif |
| 85 | |
| 86 | #ifdef CONFIG_MODE_SKAS |
| 87 | |
| 88 | #include "skas.h" |
| 89 | #include "skas_ptrace.h" |
| 90 | #include "asm/mmu_context.h" |
| 91 | |
| 92 | long write_ldt_entry(struct mm_id * mm_idp, int func, struct user_desc * desc, |
| 93 | void **addr, int done) |
| 94 | { |
| 95 | long res; |
| 96 | |
| 97 | if(proc_mm){ |
| 98 | /* This is a special handling for the case, that the mm to |
| 99 | * modify isn't current->active_mm. |
| 100 | * If this is called directly by modify_ldt, |
| 101 | * (current->active_mm->context.skas.u == mm_idp) |
| 102 | * will be true. So no call to switch_mm_skas(mm_idp) is done. |
| 103 | * If this is called in case of init_new_ldt or PTRACE_LDT, |
| 104 | * mm_idp won't belong to current->active_mm, but child->mm. |
| 105 | * So we need to switch child's mm into our userspace, then |
| 106 | * later switch back. |
| 107 | * |
| 108 | * Note: I'm unshure: should interrupts be disabled here? |
| 109 | */ |
| 110 | if(!current->active_mm || current->active_mm == &init_mm || |
| 111 | mm_idp != ¤t->active_mm->context.skas.id) |
| 112 | switch_mm_skas(mm_idp); |
| 113 | } |
| 114 | |
| 115 | if(ptrace_ldt) { |
| 116 | struct ptrace_ldt ldt_op = (struct ptrace_ldt) { |
| 117 | .func = func, |
| 118 | .ptr = desc, |
| 119 | .bytecount = sizeof(*desc)}; |
| 120 | u32 cpu; |
| 121 | int pid; |
| 122 | |
| 123 | if(!proc_mm) |
| 124 | pid = mm_idp->u.pid; |
| 125 | else { |
| 126 | cpu = get_cpu(); |
| 127 | pid = userspace_pid[cpu]; |
| 128 | } |
| 129 | |
| 130 | res = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op); |
| 131 | if(res) |
| 132 | res = errno; |
| 133 | |
| 134 | if(proc_mm) |
| 135 | put_cpu(); |
| 136 | } |
| 137 | else { |
| 138 | void *stub_addr; |
| 139 | res = syscall_stub_data(mm_idp, (unsigned long *)desc, |
| 140 | (sizeof(*desc) + sizeof(long) - 1) & |
| 141 | ~(sizeof(long) - 1), |
| 142 | addr, &stub_addr); |
| 143 | if(!res){ |
| 144 | unsigned long args[] = { func, |
| 145 | (unsigned long)stub_addr, |
| 146 | sizeof(*desc), |
| 147 | 0, 0, 0 }; |
| 148 | res = run_syscall_stub(mm_idp, __NR_modify_ldt, args, |
| 149 | 0, addr, done); |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | if(proc_mm){ |
| 154 | /* This is the second part of special handling, that makes |
| 155 | * PTRACE_LDT possible to implement. |
| 156 | */ |
| 157 | if(current->active_mm && current->active_mm != &init_mm && |
| 158 | mm_idp != ¤t->active_mm->context.skas.id) |
| 159 | switch_mm_skas(¤t->active_mm->context.skas.id); |
| 160 | } |
| 161 | |
| 162 | return res; |
| 163 | } |
| 164 | |
| 165 | static long read_ldt_from_host(void __user * ptr, unsigned long bytecount) |
| 166 | { |
| 167 | int res, n; |
| 168 | struct ptrace_ldt ptrace_ldt = (struct ptrace_ldt) { |
| 169 | .func = 0, |
| 170 | .bytecount = bytecount, |
| 171 | .ptr = (void *)kmalloc(bytecount, GFP_KERNEL)}; |
| 172 | u32 cpu; |
| 173 | |
| 174 | if(ptrace_ldt.ptr == NULL) |
| 175 | return -ENOMEM; |
| 176 | |
| 177 | /* This is called from sys_modify_ldt only, so userspace_pid gives |
| 178 | * us the right number |
| 179 | */ |
| 180 | |
| 181 | cpu = get_cpu(); |
| 182 | res = ptrace(PTRACE_LDT, userspace_pid[cpu], 0, |
| 183 | (unsigned long) &ptrace_ldt); |
| 184 | put_cpu(); |
| 185 | if(res < 0) |
| 186 | goto out; |
| 187 | |
| 188 | n = copy_to_user(ptr, ptrace_ldt.ptr, res); |
| 189 | if(n != 0) |
| 190 | res = -EFAULT; |
| 191 | |
| 192 | out: |
| 193 | kfree(ptrace_ldt.ptr); |
| 194 | |
| 195 | return res; |
| 196 | } |
| 197 | |
| 198 | /* |
| 199 | * In skas mode, we hold our own ldt data in UML. |
| 200 | * Thus, the code implementing sys_modify_ldt_skas |
| 201 | * is very similar to (and mostly stolen from) sys_modify_ldt |
| 202 | * for arch/i386/kernel/ldt.c |
| 203 | * The routines copied and modified in part are: |
| 204 | * - read_ldt |
| 205 | * - read_default_ldt |
| 206 | * - write_ldt |
| 207 | * - sys_modify_ldt_skas |
| 208 | */ |
| 209 | |
| 210 | static int read_ldt(void __user * ptr, unsigned long bytecount) |
| 211 | { |
| 212 | int i, err = 0; |
| 213 | unsigned long size; |
| 214 | uml_ldt_t * ldt = ¤t->mm->context.skas.ldt; |
| 215 | |
| 216 | if(!ldt->entry_count) |
| 217 | goto out; |
| 218 | if(bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES) |
| 219 | bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES; |
| 220 | err = bytecount; |
| 221 | |
| 222 | if(ptrace_ldt){ |
| 223 | return read_ldt_from_host(ptr, bytecount); |
| 224 | } |
| 225 | |
| 226 | down(&ldt->semaphore); |
| 227 | if(ldt->entry_count <= LDT_DIRECT_ENTRIES){ |
| 228 | size = LDT_ENTRY_SIZE*LDT_DIRECT_ENTRIES; |
| 229 | if(size > bytecount) |
| 230 | size = bytecount; |
| 231 | if(copy_to_user(ptr, ldt->entries, size)) |
| 232 | err = -EFAULT; |
| 233 | bytecount -= size; |
| 234 | ptr += size; |
| 235 | } |
| 236 | else { |
| 237 | for(i=0; i<ldt->entry_count/LDT_ENTRIES_PER_PAGE && bytecount; |
| 238 | i++){ |
| 239 | size = PAGE_SIZE; |
| 240 | if(size > bytecount) |
| 241 | size = bytecount; |
| 242 | if(copy_to_user(ptr, ldt->pages[i], size)){ |
| 243 | err = -EFAULT; |
| 244 | break; |
| 245 | } |
| 246 | bytecount -= size; |
| 247 | ptr += size; |
| 248 | } |
| 249 | } |
| 250 | up(&ldt->semaphore); |
| 251 | |
| 252 | if(bytecount == 0 || err == -EFAULT) |
| 253 | goto out; |
| 254 | |
| 255 | if(clear_user(ptr, bytecount)) |
| 256 | err = -EFAULT; |
| 257 | |
| 258 | out: |
| 259 | return err; |
| 260 | } |
| 261 | |
| 262 | static int read_default_ldt(void __user * ptr, unsigned long bytecount) |
| 263 | { |
| 264 | int err; |
| 265 | |
| 266 | if(bytecount > 5*LDT_ENTRY_SIZE) |
| 267 | bytecount = 5*LDT_ENTRY_SIZE; |
| 268 | |
| 269 | err = bytecount; |
| 270 | /* UML doesn't support lcall7 and lcall27. |
| 271 | * So, we don't really have a default ldt, but emulate |
| 272 | * an empty ldt of common host default ldt size. |
| 273 | */ |
| 274 | if(clear_user(ptr, bytecount)) |
| 275 | err = -EFAULT; |
| 276 | |
| 277 | return err; |
| 278 | } |
| 279 | |
| 280 | static int write_ldt(void __user * ptr, unsigned long bytecount, int func) |
| 281 | { |
| 282 | uml_ldt_t * ldt = ¤t->mm->context.skas.ldt; |
| 283 | struct mm_id * mm_idp = ¤t->mm->context.skas.id; |
| 284 | int i, err; |
| 285 | struct user_desc ldt_info; |
| 286 | struct ldt_entry entry0, *ldt_p; |
| 287 | void *addr = NULL; |
| 288 | |
| 289 | err = -EINVAL; |
| 290 | if(bytecount != sizeof(ldt_info)) |
| 291 | goto out; |
| 292 | err = -EFAULT; |
| 293 | if(copy_from_user(&ldt_info, ptr, sizeof(ldt_info))) |
| 294 | goto out; |
| 295 | |
| 296 | err = -EINVAL; |
| 297 | if(ldt_info.entry_number >= LDT_ENTRIES) |
| 298 | goto out; |
| 299 | if(ldt_info.contents == 3){ |
| 300 | if (func == 1) |
| 301 | goto out; |
| 302 | if (ldt_info.seg_not_present == 0) |
| 303 | goto out; |
| 304 | } |
| 305 | |
| 306 | if(!ptrace_ldt) |
| 307 | down(&ldt->semaphore); |
| 308 | |
| 309 | err = write_ldt_entry(mm_idp, func, &ldt_info, &addr, 1); |
| 310 | if(err) |
| 311 | goto out_unlock; |
| 312 | else if(ptrace_ldt) { |
| 313 | /* With PTRACE_LDT available, this is used as a flag only */ |
| 314 | ldt->entry_count = 1; |
| 315 | goto out; |
| 316 | } |
| 317 | |
| 318 | if(ldt_info.entry_number >= ldt->entry_count && |
| 319 | ldt_info.entry_number >= LDT_DIRECT_ENTRIES){ |
| 320 | for(i=ldt->entry_count/LDT_ENTRIES_PER_PAGE; |
| 321 | i*LDT_ENTRIES_PER_PAGE <= ldt_info.entry_number; |
| 322 | i++){ |
| 323 | if(i == 0) |
| 324 | memcpy(&entry0, ldt->entries, sizeof(entry0)); |
| 325 | ldt->pages[i] = (struct ldt_entry *) |
| 326 | __get_free_page(GFP_KERNEL|__GFP_ZERO); |
| 327 | if(!ldt->pages[i]){ |
| 328 | err = -ENOMEM; |
| 329 | /* Undo the change in host */ |
| 330 | memset(&ldt_info, 0, sizeof(ldt_info)); |
| 331 | write_ldt_entry(mm_idp, 1, &ldt_info, &addr, 1); |
| 332 | goto out_unlock; |
| 333 | } |
| 334 | if(i == 0) { |
| 335 | memcpy(ldt->pages[0], &entry0, sizeof(entry0)); |
| 336 | memcpy(ldt->pages[0]+1, ldt->entries+1, |
| 337 | sizeof(entry0)*(LDT_DIRECT_ENTRIES-1)); |
| 338 | } |
| 339 | ldt->entry_count = (i + 1) * LDT_ENTRIES_PER_PAGE; |
| 340 | } |
| 341 | } |
| 342 | if(ldt->entry_count <= ldt_info.entry_number) |
| 343 | ldt->entry_count = ldt_info.entry_number + 1; |
| 344 | |
| 345 | if(ldt->entry_count <= LDT_DIRECT_ENTRIES) |
| 346 | ldt_p = ldt->entries + ldt_info.entry_number; |
| 347 | else |
| 348 | ldt_p = ldt->pages[ldt_info.entry_number/LDT_ENTRIES_PER_PAGE] + |
| 349 | ldt_info.entry_number%LDT_ENTRIES_PER_PAGE; |
| 350 | |
| 351 | if(ldt_info.base_addr == 0 && ldt_info.limit == 0 && |
| 352 | (func == 1 || LDT_empty(&ldt_info))){ |
| 353 | ldt_p->a = 0; |
| 354 | ldt_p->b = 0; |
| 355 | } |
| 356 | else{ |
| 357 | if (func == 1) |
| 358 | ldt_info.useable = 0; |
| 359 | ldt_p->a = LDT_entry_a(&ldt_info); |
| 360 | ldt_p->b = LDT_entry_b(&ldt_info); |
| 361 | } |
| 362 | err = 0; |
| 363 | |
| 364 | out_unlock: |
| 365 | up(&ldt->semaphore); |
| 366 | out: |
| 367 | return err; |
| 368 | } |
| 369 | |
| 370 | static long do_modify_ldt_skas(int func, void __user *ptr, |
| 371 | unsigned long bytecount) |
| 372 | { |
| 373 | int ret = -ENOSYS; |
| 374 | |
| 375 | switch (func) { |
| 376 | case 0: |
| 377 | ret = read_ldt(ptr, bytecount); |
| 378 | break; |
| 379 | case 1: |
| 380 | case 0x11: |
| 381 | ret = write_ldt(ptr, bytecount, func); |
| 382 | break; |
| 383 | case 2: |
| 384 | ret = read_default_ldt(ptr, bytecount); |
| 385 | break; |
| 386 | } |
| 387 | return ret; |
| 388 | } |
| 389 | |
| 390 | short dummy_list[9] = {0, -1}; |
| 391 | short * host_ldt_entries = NULL; |
| 392 | |
| 393 | void ldt_get_host_info(void) |
| 394 | { |
| 395 | long ret; |
| 396 | struct ldt_entry * ldt; |
| 397 | int i, size, k, order; |
| 398 | |
| 399 | host_ldt_entries = dummy_list+1; |
| 400 | |
| 401 | for(i = LDT_PAGES_MAX-1, order=0; i; i>>=1, order++); |
| 402 | |
| 403 | ldt = (struct ldt_entry *) |
| 404 | __get_free_pages(GFP_KERNEL|__GFP_ZERO, order); |
| 405 | if(ldt == NULL) { |
| 406 | printk("ldt_get_host_info: couldn't allocate buffer for host ldt\n"); |
| 407 | return; |
| 408 | } |
| 409 | |
| 410 | ret = modify_ldt(0, ldt, (1<<order)*PAGE_SIZE); |
| 411 | if(ret < 0) { |
| 412 | printk("ldt_get_host_info: couldn't read host ldt\n"); |
| 413 | goto out_free; |
| 414 | } |
| 415 | if(ret == 0) { |
| 416 | /* default_ldt is active, simply write an empty entry 0 */ |
| 417 | host_ldt_entries = dummy_list; |
| 418 | goto out_free; |
| 419 | } |
| 420 | |
| 421 | for(i=0, size=0; i<ret/LDT_ENTRY_SIZE; i++){ |
| 422 | if(ldt[i].a != 0 || ldt[i].b != 0) |
| 423 | size++; |
| 424 | } |
| 425 | |
| 426 | if(size < sizeof(dummy_list)/sizeof(dummy_list[0])) { |
| 427 | host_ldt_entries = dummy_list; |
| 428 | } |
| 429 | else { |
| 430 | size = (size + 1) * sizeof(dummy_list[0]); |
| 431 | host_ldt_entries = (short *)kmalloc(size, GFP_KERNEL); |
| 432 | if(host_ldt_entries == NULL) { |
| 433 | printk("ldt_get_host_info: couldn't allocate host ldt list\n"); |
| 434 | goto out_free; |
| 435 | } |
| 436 | } |
| 437 | |
| 438 | for(i=0, k=0; i<ret/LDT_ENTRY_SIZE; i++){ |
| 439 | if(ldt[i].a != 0 || ldt[i].b != 0) { |
| 440 | host_ldt_entries[k++] = i; |
| 441 | } |
| 442 | } |
| 443 | host_ldt_entries[k] = -1; |
| 444 | |
| 445 | out_free: |
| 446 | free_pages((unsigned long)ldt, order); |
| 447 | } |
| 448 | |
| 449 | long init_new_ldt(struct mmu_context_skas * new_mm, |
| 450 | struct mmu_context_skas * from_mm) |
| 451 | { |
| 452 | struct user_desc desc; |
| 453 | short * num_p; |
| 454 | int i; |
| 455 | long page, err=0; |
| 456 | void *addr = NULL; |
| 457 | |
| 458 | memset(&desc, 0, sizeof(desc)); |
| 459 | |
| 460 | if(!ptrace_ldt) |
| 461 | init_MUTEX(&new_mm->ldt.semaphore); |
| 462 | |
| 463 | if(!from_mm){ |
| 464 | /* |
| 465 | * We have to initialize a clean ldt. |
| 466 | */ |
| 467 | if(proc_mm) { |
| 468 | /* |
| 469 | * If the new mm was created using proc_mm, host's |
| 470 | * default-ldt currently is assigned, which normally |
| 471 | * contains the call-gates for lcall7 and lcall27. |
| 472 | * To remove these gates, we simply write an empty |
| 473 | * entry as number 0 to the host. |
| 474 | */ |
| 475 | err = write_ldt_entry(&new_mm->id, 1, &desc, |
| 476 | &addr, 1); |
| 477 | } |
| 478 | else{ |
| 479 | /* |
| 480 | * Now we try to retrieve info about the ldt, we |
| 481 | * inherited from the host. All ldt-entries found |
| 482 | * will be reset in the following loop |
| 483 | */ |
| 484 | if(host_ldt_entries == NULL) |
| 485 | ldt_get_host_info(); |
| 486 | for(num_p=host_ldt_entries; *num_p != -1; num_p++){ |
| 487 | desc.entry_number = *num_p; |
| 488 | err = write_ldt_entry(&new_mm->id, 1, &desc, |
| 489 | &addr, *(num_p + 1) == -1); |
| 490 | if(err) |
| 491 | break; |
| 492 | } |
| 493 | } |
| 494 | new_mm->ldt.entry_count = 0; |
| 495 | } |
| 496 | else if (!ptrace_ldt) { |
| 497 | /* Our local LDT is used to supply the data for |
| 498 | * modify_ldt(READLDT), if PTRACE_LDT isn't available, |
| 499 | * i.e., we have to use the stub for modify_ldt, which |
| 500 | * can't handle the big read buffer of up to 64kB. |
| 501 | */ |
| 502 | down(&from_mm->ldt.semaphore); |
| 503 | if(from_mm->ldt.entry_count <= LDT_DIRECT_ENTRIES){ |
| 504 | memcpy(new_mm->ldt.entries, from_mm->ldt.entries, |
| 505 | sizeof(new_mm->ldt.entries)); |
| 506 | } |
| 507 | else{ |
| 508 | i = from_mm->ldt.entry_count / LDT_ENTRIES_PER_PAGE; |
| 509 | while(i-->0){ |
| 510 | page = __get_free_page(GFP_KERNEL|__GFP_ZERO); |
| 511 | if (!page){ |
| 512 | err = -ENOMEM; |
| 513 | break; |
| 514 | } |
| 515 | new_mm->ldt.pages[i] = (struct ldt_entry*)page; |
| 516 | memcpy(new_mm->ldt.pages[i], |
| 517 | from_mm->ldt.pages[i], PAGE_SIZE); |
| 518 | } |
| 519 | } |
| 520 | new_mm->ldt.entry_count = from_mm->ldt.entry_count; |
| 521 | up(&from_mm->ldt.semaphore); |
| 522 | } |
| 523 | |
| 524 | return err; |
| 525 | } |
| 526 | |
| 527 | |
| 528 | void free_ldt(struct mmu_context_skas * mm) |
| 529 | { |
| 530 | int i; |
| 531 | |
| 532 | if(!ptrace_ldt && mm->ldt.entry_count > LDT_DIRECT_ENTRIES){ |
| 533 | i = mm->ldt.entry_count / LDT_ENTRIES_PER_PAGE; |
| 534 | while(i-- > 0){ |
| 535 | free_page((long )mm->ldt.pages[i]); |
| 536 | } |
| 537 | } |
| 538 | mm->ldt.entry_count = 0; |
| 539 | } |
| 540 | #endif |
| 541 | |
| 542 | int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount) |
| 543 | { |
| 544 | return(CHOOSE_MODE_PROC(do_modify_ldt_tt, do_modify_ldt_skas, func, |
| 545 | ptr, bytecount)); |
| 546 | } |