LXR linux/arch/sparc/kernel/sys_sparc

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