1 // SPDX-License-Identifier: GPL-2.0 2 /* linux/arch/sparc64/kernel/sys_sparc.c 3 * 4 * This file contains various random system calls that 5 * have a non-standard calling sequence on the Linux/sparc 6 * platform. 7 */ 8 9 #include <linux/errno.h> 10 #include <linux/types.h> 11 #include <linux/sched/signal.h> 12 #include <linux/sched/mm.h> 13 #include <linux/sched/debug.h> 14 #include <linux/fs.h> 15 #include <linux/file.h> 16 #include <linux/mm.h> 17 #include <linux/sem.h> 18 #include <linux/msg.h> 19 #include <linux/shm.h> 20 #include <linux/stat.h> 21 #include <linux/mman.h> 22 #include <linux/utsname.h> 23 #include <linux/smp.h> 24 #include <linux/slab.h> 25 #include <linux/syscalls.h> 26 #include <linux/ipc.h> 27 #include <linux/personality.h> 28 #include <linux/random.h> 29 #include <linux/export.h> 30 #include <linux/context_tracking.h> 31 #include <linux/timex.h> 32 #include <linux/uaccess.h> 33 #include <linux/hugetlb.h> 34 35 #include <asm/utrap.h> 36 #include <asm/unistd.h> 37 38 #include "entry.h" 39 #include "kernel.h" 40 #include "systbls.h" 41 42 /* #define DEBUG_UNIMP_SYSCALL */ 43 44 SYSCALL_DEFINE0(getpagesize) 45 { 46 return PAGE_SIZE; 47 } 48 49 /* Does addr --> addr+len fall within 4GB of the VA-space hole or 50 * overflow past the end of the 64-bit address space? 51 */ 52 static inline int invalid_64bit_range(unsigned long addr, unsigned long len) 53 { 54 unsigned long va_exclude_start, va_exclude_end; 55 56 va_exclude_start = VA_EXCLUDE_START; 57 va_exclude_end = VA_EXCLUDE_END; 58 59 if (unlikely(len >= va_exclude_start)) 60 return 1; 61 62 if (unlikely((addr + len) < addr)) 63 return 1; 64 65 if (unlikely((addr >= va_exclude_start && addr < va_exclude_end) || 66 ((addr + len) >= va_exclude_start && 67 (addr + len) < va_exclude_end))) 68 return 1; 69 70 return 0; 71 } 72 73 /* These functions differ from the default implementations in 74 * mm/mmap.c in two ways: 75 * 76 * 1) For file backed MAP_SHARED mmap()'s we D-cache color align, 77 * for fixed such mappings we just validate what the user gave us. 78 * 2) For 64-bit tasks we avoid mapping anything within 4GB of 79 * the spitfire/niagara VA-hole. 80 */ 81 82 static inline unsigned long COLOR_ALIGN(unsigned long addr, 83 unsigned long pgoff) 84 { 85 unsigned long base = (addr+SHMLBA-1)&~(SHMLBA-1); 86 unsigned long off = (pgoff<<PAGE_SHIFT) & (SHMLBA-1); 87 88 return base + off; 89 } 90 91 static unsigned long get_align_mask(struct file *filp, unsigned long flags) 92 { 93 if (filp && is_file_hugepages(filp)) 94 return huge_page_mask_align(filp); 95 if (filp || (flags & MAP_SHARED)) 96 return PAGE_MASK & (SHMLBA - 1); 97 98 return 0; 99 } 100 101 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags, vm_flags_t vm_flags) 102 { 103 struct mm_struct *mm = current->mm; 104 struct vm_area_struct * vma; 105 unsigned long task_size = TASK_SIZE; 106 int do_color_align; 107 struct vm_unmapped_area_info info = {}; 108 bool file_hugepage = false; 109 110 if (filp && is_file_hugepages(filp)) 111 file_hugepage = true; 112 113 if (flags & MAP_FIXED) { 114 /* We do not accept a shared mapping if it would violate 115 * cache aliasing constraints. 116 */ 117 if (!file_hugepage && (flags & MAP_SHARED) && 118 ((addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))) 119 return -EINVAL; 120 return addr; 121 } 122 123 if (test_thread_flag(TIF_32BIT)) 124 task_size = STACK_TOP32; 125 if (unlikely(len > task_size || len >= VA_EXCLUDE_START)) 126 return -ENOMEM; 127 128 do_color_align = 0; 129 if ((filp || (flags & MAP_SHARED)) && !file_hugepage) 130 do_color_align = 1; 131 132 if (addr) { 133 if (do_color_align) 134 addr = COLOR_ALIGN(addr, pgoff); 135 else 136 addr = PAGE_ALIGN(addr); 137 138 vma = find_vma(mm, addr); 139 if (task_size - len >= addr && 140 (!vma || addr + len <= vm_start_gap(vma))) 141 return addr; 142 } 143 144 info.length = len; 145 info.low_limit = TASK_UNMAPPED_BASE; 146 info.high_limit = min(task_size, VA_EXCLUDE_START); 147 info.align_mask = get_align_mask(filp, flags); 148 if (!file_hugepage) 149 info.align_offset = pgoff << PAGE_SHIFT; 150 addr = vm_unmapped_area(&info); 151 152 if ((addr & ~PAGE_MASK) && task_size > VA_EXCLUDE_END) { 153 VM_BUG_ON(addr != -ENOMEM); 154 info.low_limit = VA_EXCLUDE_END; 155 info.high_limit = task_size; 156 addr = vm_unmapped_area(&info); 157 } 158 159 return addr; 160 } 161 162 unsigned long 163 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 164 const unsigned long len, const unsigned long pgoff, 165 const unsigned long flags, vm_flags_t vm_flags) 166 { 167 struct vm_area_struct *vma; 168 struct mm_struct *mm = current->mm; 169 unsigned long task_size = STACK_TOP32; 170 unsigned long addr = addr0; 171 int do_color_align; 172 struct vm_unmapped_area_info info = {}; 173 bool file_hugepage = false; 174 175 /* This should only ever run for 32-bit processes. */ 176 BUG_ON(!test_thread_flag(TIF_32BIT)); 177 178 if (filp && is_file_hugepages(filp)) 179 file_hugepage = true; 180 181 if (flags & MAP_FIXED) { 182 /* We do not accept a shared mapping if it would violate 183 * cache aliasing constraints. 184 */ 185 if (!file_hugepage && (flags & MAP_SHARED) && 186 ((addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))) 187 return -EINVAL; 188 return addr; 189 } 190 191 if (unlikely(len > task_size)) 192 return -ENOMEM; 193 194 do_color_align = 0; 195 if ((filp || (flags & MAP_SHARED)) && !file_hugepage) 196 do_color_align = 1; 197 198 /* requesting a specific address */ 199 if (addr) { 200 if (do_color_align) 201 addr = COLOR_ALIGN(addr, pgoff); 202 else 203 addr = PAGE_ALIGN(addr); 204 205 vma = find_vma(mm, addr); 206 if (task_size - len >= addr && 207 (!vma || addr + len <= vm_start_gap(vma))) 208 return addr; 209 } 210 211 info.flags = VM_UNMAPPED_AREA_TOPDOWN; 212 info.length = len; 213 info.low_limit = PAGE_SIZE; 214 info.high_limit = mm->mmap_base; 215 info.align_mask = get_align_mask(filp, flags); 216 if (!file_hugepage) 217 info.align_offset = pgoff << PAGE_SHIFT; 218 addr = vm_unmapped_area(&info); 219 220 /* 221 * A failed mmap() very likely causes application failure, 222 * so fall back to the bottom-up function here. This scenario 223 * can happen with large stack limits and large mmap() 224 * allocations. 225 */ 226 if (addr & ~PAGE_MASK) { 227 VM_BUG_ON(addr != -ENOMEM); 228 info.flags = 0; 229 info.low_limit = TASK_UNMAPPED_BASE; 230 info.high_limit = STACK_TOP32; 231 addr = vm_unmapped_area(&info); 232 } 233 234 return addr; 235 } 236 237 /* Try to align mapping such that we align it as much as possible. */ 238 unsigned long get_fb_unmapped_area(struct file *filp, unsigned long orig_addr, unsigned long len, unsigned long pgoff, unsigned long flags) 239 { 240 unsigned long align_goal, addr = -ENOMEM; 241 242 if (flags & MAP_FIXED) { 243 /* Ok, don't mess with it. */ 244 return mm_get_unmapped_area(current->mm, NULL, orig_addr, len, pgoff, flags); 245 } 246 flags &= ~MAP_SHARED; 247 248 align_goal = PAGE_SIZE; 249 if (len >= (4UL * 1024 * 1024)) 250 align_goal = (4UL * 1024 * 1024); 251 else if (len >= (512UL * 1024)) 252 align_goal = (512UL * 1024); 253 else if (len >= (64UL * 1024)) 254 align_goal = (64UL * 1024); 255 256 do { 257 addr = mm_get_unmapped_area(current->mm, NULL, orig_addr, 258 len + (align_goal - PAGE_SIZE), pgoff, flags); 259 if (!(addr & ~PAGE_MASK)) { 260 addr = (addr + (align_goal - 1UL)) & ~(align_goal - 1UL); 261 break; 262 } 263 264 if (align_goal == (4UL * 1024 * 1024)) 265 align_goal = (512UL * 1024); 266 else if (align_goal == (512UL * 1024)) 267 align_goal = (64UL * 1024); 268 else 269 align_goal = PAGE_SIZE; 270 } while ((addr & ~PAGE_MASK) && align_goal > PAGE_SIZE); 271 272 /* Mapping is smaller than 64K or larger areas could not 273 * be obtained. 274 */ 275 if (addr & ~PAGE_MASK) 276 addr = mm_get_unmapped_area(current->mm, NULL, orig_addr, len, pgoff, flags); 277 278 return addr; 279 } 280 EXPORT_SYMBOL(get_fb_unmapped_area); 281 282 /* Essentially the same as PowerPC. */ 283 static unsigned long mmap_rnd(void) 284 { 285 unsigned long rnd = 0UL; 286 287 if (current->flags & PF_RANDOMIZE) { 288 unsigned long val = get_random_long(); 289 if (test_thread_flag(TIF_32BIT)) 290 rnd = (val % (1UL << (23UL-PAGE_SHIFT))); 291 else 292 rnd = (val % (1UL << (30UL-PAGE_SHIFT))); 293 } 294 return rnd << PAGE_SHIFT; 295 } 296 297 void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) 298 { 299 unsigned long random_factor = mmap_rnd(); 300 unsigned long gap; 301 302 /* 303 * Fall back to the standard layout if the personality 304 * bit is set, or if the expected stack growth is unlimited: 305 */ 306 gap = rlim_stack->rlim_cur; 307 if (!test_thread_flag(TIF_32BIT) || 308 (current->personality & ADDR_COMPAT_LAYOUT) || 309 gap == RLIM_INFINITY || 310 sysctl_legacy_va_layout) { 311 mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; 312 clear_bit(MMF_TOPDOWN, &mm->flags); 313 } else { 314 /* We know it's 32-bit */ 315 unsigned long task_size = STACK_TOP32; 316 317 if (gap < 128 * 1024 * 1024) 318 gap = 128 * 1024 * 1024; 319 if (gap > (task_size / 6 * 5)) 320 gap = (task_size / 6 * 5); 321 322 mm->mmap_base = PAGE_ALIGN(task_size - gap - random_factor); 323 set_bit(MMF_TOPDOWN, &mm->flags); 324 } 325 } 326 327 /* 328 * sys_pipe() is the normal C calling standard for creating 329 * a pipe. It's not the way unix traditionally does this, though. 330 */ 331 SYSCALL_DEFINE0(sparc_pipe) 332 { 333 int fd[2]; 334 int error; 335 336 error = do_pipe_flags(fd, 0); 337 if (error) 338 goto out; 339 current_pt_regs()->u_regs[UREG_I1] = fd[1]; 340 error = fd[0]; 341 out: 342 return error; 343 } 344 345 /* 346 * sys_ipc() is the de-multiplexer for the SysV IPC calls.. 347 * 348 * This is really horribly ugly. 349 */ 350 351 SYSCALL_DEFINE6(sparc_ipc, unsigned int, call, int, first, unsigned long, second, 352 unsigned long, third, void __user *, ptr, long, fifth) 353 { 354 long err; 355 356 if (!IS_ENABLED(CONFIG_SYSVIPC)) 357 return -ENOSYS; 358 359 /* No need for backward compatibility. We can start fresh... */ 360 if (call <= SEMTIMEDOP) { 361 switch (call) { 362 case SEMOP: 363 err = ksys_semtimedop(first, ptr, 364 (unsigned int)second, NULL); 365 goto out; 366 case SEMTIMEDOP: 367 err = ksys_semtimedop(first, ptr, (unsigned int)second, 368 (const struct __kernel_timespec __user *) 369 (unsigned long) fifth); 370 goto out; 371 case SEMGET: 372 err = ksys_semget(first, (int)second, (int)third); 373 goto out; 374 case SEMCTL: { 375 err = ksys_old_semctl(first, second, 376 (int)third | IPC_64, 377 (unsigned long) ptr); 378 goto out; 379 } 380 default: 381 err = -ENOSYS; 382 goto out; 383 } 384 } 385 if (call <= MSGCTL) { 386 switch (call) { 387 case MSGSND: 388 err = ksys_msgsnd(first, ptr, (size_t)second, 389 (int)third); 390 goto out; 391 case MSGRCV: 392 err = ksys_msgrcv(first, ptr, (size_t)second, fifth, 393 (int)third); 394 goto out; 395 case MSGGET: 396 err = ksys_msgget((key_t)first, (int)second); 397 goto out; 398 case MSGCTL: 399 err = ksys_old_msgctl(first, (int)second | IPC_64, ptr); 400 goto out; 401 default: 402 err = -ENOSYS; 403 goto out; 404 } 405 } 406 if (call <= SHMCTL) { 407 switch (call) { 408 case SHMAT: { 409 ulong raddr; 410 err = do_shmat(first, ptr, (int)second, &raddr, SHMLBA); 411 if (!err) { 412 if (put_user(raddr, 413 (ulong __user *) third)) 414 err = -EFAULT; 415 } 416 goto out; 417 } 418 case SHMDT: 419 err = ksys_shmdt(ptr); 420 goto out; 421 case SHMGET: 422 err = ksys_shmget(first, (size_t)second, (int)third); 423 goto out; 424 case SHMCTL: 425 err = ksys_old_shmctl(first, (int)second | IPC_64, ptr); 426 goto out; 427 default: 428 err = -ENOSYS; 429 goto out; 430 } 431 } else { 432 err = -ENOSYS; 433 } 434 out: 435 return err; 436 } 437 438 SYSCALL_DEFINE1(sparc64_personality, unsigned long, personality) 439 { 440 long ret; 441 442 if (personality(current->personality) == PER_LINUX32 && 443 personality(personality) == PER_LINUX) 444 personality |= PER_LINUX32; 445 ret = sys_personality(personality); 446 if (personality(ret) == PER_LINUX32) 447 ret &= ~PER_LINUX32; 448 449 return ret; 450 } 451 452 int sparc_mmap_check(unsigned long addr, unsigned long len) 453 { 454 if (test_thread_flag(TIF_32BIT)) { 455 if (len >= STACK_TOP32) 456 return -EINVAL; 457 458 if (addr > STACK_TOP32 - len) 459 return -EINVAL; 460 } else { 461 if (len >= VA_EXCLUDE_START) 462 return -EINVAL; 463 464 if (invalid_64bit_range(addr, len)) 465 return -EINVAL; 466 } 467 468 return 0; 469 } 470 471 /* Linux version of mmap */ 472 SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, 473 unsigned long, prot, unsigned long, flags, unsigned long, fd, 474 unsigned long, off) 475 { 476 unsigned long retval = -EINVAL; 477 478 if ((off + PAGE_ALIGN(len)) < off) 479 goto out; 480 if (off & ~PAGE_MASK) 481 goto out; 482 retval = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT); 483 out: 484 return retval; 485 } 486 487 SYSCALL_DEFINE2(64_munmap, unsigned long, addr, size_t, len) 488 { 489 if (invalid_64bit_range(addr, len)) 490 return -EINVAL; 491 492 return vm_munmap(addr, len); 493 } 494 495 SYSCALL_DEFINE5(64_mremap, unsigned long, addr, unsigned long, old_len, 496 unsigned long, new_len, unsigned long, flags, 497 unsigned long, new_addr) 498 { 499 if (test_thread_flag(TIF_32BIT)) 500 return -EINVAL; 501 return sys_mremap(addr, old_len, new_len, flags, new_addr); 502 } 503 504 SYSCALL_DEFINE0(nis_syscall) 505 { 506 static int count; 507 struct pt_regs *regs = current_pt_regs(); 508 509 /* Don't make the system unusable, if someone goes stuck */ 510 if (count++ > 5) 511 return -ENOSYS; 512 513 printk ("Unimplemented SPARC system call %ld\n",regs->u_regs[1]); 514 #ifdef DEBUG_UNIMP_SYSCALL 515 show_regs (regs); 516 #endif 517 518 return -ENOSYS; 519 } 520 521 /* #define DEBUG_SPARC_BREAKPOINT */ 522 523 asmlinkage void sparc_breakpoint(struct pt_regs *regs) 524 { 525 enum ctx_state prev_state = exception_enter(); 526 527 if (test_thread_flag(TIF_32BIT)) { 528 regs->tpc &= 0xffffffff; 529 regs->tnpc &= 0xffffffff; 530 } 531 #ifdef DEBUG_SPARC_BREAKPOINT 532 printk ("TRAP: Entering kernel PC=%lx, nPC=%lx\n", regs->tpc, regs->tnpc); 533 #endif 534 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->tpc); 535 #ifdef DEBUG_SPARC_BREAKPOINT 536 printk ("TRAP: Returning to space: PC=%lx nPC=%lx\n", regs->tpc, regs->tnpc); 537 #endif 538 exception_exit(prev_state); 539 } 540 541 SYSCALL_DEFINE2(getdomainname, char __user *, name, int, len) 542 { 543 int nlen, err; 544 char tmp[__NEW_UTS_LEN + 1]; 545 546 if (len < 0) 547 return -EINVAL; 548 549 down_read(&uts_sem); 550 551 nlen = strlen(utsname()->domainname) + 1; 552 err = -EINVAL; 553 if (nlen > len) 554 goto out_unlock; 555 memcpy(tmp, utsname()->domainname, nlen); 556 557 up_read(&uts_sem); 558 559 if (copy_to_user(name, tmp, nlen)) 560 return -EFAULT; 561 return 0; 562 563 out_unlock: 564 up_read(&uts_sem); 565 return err; 566 } 567 568 SYSCALL_DEFINE1(sparc_adjtimex, struct __kernel_timex __user *, txc_p) 569 { 570 struct __kernel_timex txc; 571 struct __kernel_old_timeval *tv = (void *)&txc.time; 572 int ret; 573 574 /* Copy the user data space into the kernel copy 575 * structure. But bear in mind that the structures 576 * may change 577 */ 578 if (copy_from_user(&txc, txc_p, sizeof(txc))) 579 return -EFAULT; 580 581 /* 582 * override for sparc64 specific timeval type: tv_usec 583 * is 32 bit wide instead of 64-bit in __kernel_timex 584 */ 585 txc.time.tv_usec = tv->tv_usec; 586 ret = do_adjtimex(&txc); 587 tv->tv_usec = txc.time.tv_usec; 588 589 return copy_to_user(txc_p, &txc, sizeof(txc)) ? -EFAULT : ret; 590 } 591 592 SYSCALL_DEFINE2(sparc_clock_adjtime, const clockid_t, which_clock, 593 struct __kernel_timex __user *, txc_p) 594 { 595 struct __kernel_timex txc; 596 struct __kernel_old_timeval *tv = (void *)&txc.time; 597 int ret; 598 599 if (!IS_ENABLED(CONFIG_POSIX_TIMERS)) { 600 pr_err_once("process %d (%s) attempted a POSIX timer syscall " 601 "while CONFIG_POSIX_TIMERS is not set\n", 602 current->pid, current->comm); 603 604 return -ENOSYS; 605 } 606 607 /* Copy the user data space into the kernel copy 608 * structure. But bear in mind that the structures 609 * may change 610 */ 611 if (copy_from_user(&txc, txc_p, sizeof(txc))) 612 return -EFAULT; 613 614 /* 615 * override for sparc64 specific timeval type: tv_usec 616 * is 32 bit wide instead of 64-bit in __kernel_timex 617 */ 618 txc.time.tv_usec = tv->tv_usec; 619 ret = do_clock_adjtime(which_clock, &txc); 620 tv->tv_usec = txc.time.tv_usec; 621 622 return copy_to_user(txc_p, &txc, sizeof(txc)) ? -EFAULT : ret; 623 } 624 625 SYSCALL_DEFINE5(utrap_install, utrap_entry_t, type, 626 utrap_handler_t, new_p, utrap_handler_t, new_d, 627 utrap_handler_t __user *, old_p, 628 utrap_handler_t __user *, old_d) 629 { 630 if (type < UT_INSTRUCTION_EXCEPTION || type > UT_TRAP_INSTRUCTION_31) 631 return -EINVAL; 632 if (new_p == (utrap_handler_t)(long)UTH_NOCHANGE) { 633 if (old_p) { 634 if (!current_thread_info()->utraps) { 635 if (put_user(NULL, old_p)) 636 return -EFAULT; 637 } else { 638 if (put_user((utrap_handler_t)(current_thread_info()->utraps[type]), old_p)) 639 return -EFAULT; 640 } 641 } 642 if (old_d) { 643 if (put_user(NULL, old_d)) 644 return -EFAULT; 645 } 646 return 0; 647 } 648 if (!current_thread_info()->utraps) { 649 current_thread_info()->utraps = 650 kcalloc(UT_TRAP_INSTRUCTION_31 + 1, sizeof(long), 651 GFP_KERNEL); 652 if (!current_thread_info()->utraps) 653 return -ENOMEM; 654 current_thread_info()->utraps[0] = 1; 655 } else { 656 if ((utrap_handler_t)current_thread_info()->utraps[type] != new_p && 657 current_thread_info()->utraps[0] > 1) { 658 unsigned long *p = current_thread_info()->utraps; 659 660 current_thread_info()->utraps = 661 kmalloc_array(UT_TRAP_INSTRUCTION_31 + 1, 662 sizeof(long), 663 GFP_KERNEL); 664 if (!current_thread_info()->utraps) { 665 current_thread_info()->utraps = p; 666 return -ENOMEM; 667 } 668 p[0]--; 669 current_thread_info()->utraps[0] = 1; 670 memcpy(current_thread_info()->utraps+1, p+1, 671 UT_TRAP_INSTRUCTION_31*sizeof(long)); 672 } 673 } 674 if (old_p) { 675 if (put_user((utrap_handler_t)(current_thread_info()->utraps[type]), old_p)) 676 return -EFAULT; 677 } 678 if (old_d) { 679 if (put_user(NULL, old_d)) 680 return -EFAULT; 681 } 682 current_thread_info()->utraps[type] = (long)new_p; 683 684 return 0; 685 } 686 687 SYSCALL_DEFINE1(memory_ordering, unsigned long, model) 688 { 689 struct pt_regs *regs = current_pt_regs(); 690 if (model >= 3) 691 return -EINVAL; 692 regs->tstate = (regs->tstate & ~TSTATE_MM) | (model << 14); 693 return 0; 694 } 695 696 SYSCALL_DEFINE5(rt_sigaction, int, sig, const struct sigaction __user *, act, 697 struct sigaction __user *, oact, void __user *, restorer, 698 size_t, sigsetsize) 699 { 700 struct k_sigaction new_ka, old_ka; 701 int ret; 702 703 /* XXX: Don't preclude handling different sized sigset_t's. */ 704 if (sigsetsize != sizeof(sigset_t)) 705 return -EINVAL; 706 707 if (act) { 708 new_ka.ka_restorer = restorer; 709 if (copy_from_user(&new_ka.sa, act, sizeof(*act))) 710 return -EFAULT; 711 } 712 713 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 714 715 if (!ret && oact) { 716 if (copy_to_user(oact, &old_ka.sa, sizeof(*oact))) 717 return -EFAULT; 718 } 719 720 return ret; 721 } 722 723 SYSCALL_DEFINE0(kern_features) 724 { 725 return KERN_FEATURE_MIXED_MODE_STACK; 726 } 727