arch/parisc/kernel/signal.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/arch/parisc/kernel/signal.c: Architecture-specific signal
   4  *  handling support.
   5  *
   6  *  Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
   7  *  Copyright (C) 2000 Linuxcare, Inc.
   8  *
   9  *  Based on the ia64, i386, and alpha versions.
  10  *
  11  *  Like the IA-64, we are a recent enough port (we are *starting*
  12  *  with glibc2.2) that we do not need to support the old non-realtime
  13  *  Linux signals.  Therefore we don't.
  14  */
  15
  16 #include <linux/sched.h>
  17 #include <linux/sched/debug.h>
  18 #include <linux/mm.h>
  19 #include <linux/smp.h>
  20 #include <linux/kernel.h>
  21 #include <linux/signal.h>
  22 #include <linux/errno.h>
  23 #include <linux/wait.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/tracehook.h>
  26 #include <linux/unistd.h>
  27 #include <linux/stddef.h>
  28 #include <linux/compat.h>
  29 #include <linux/elf.h>
  30 #include <asm/ucontext.h>
  31 #include <asm/rt_sigframe.h>
  32 #include <linux/uaccess.h>
  33 #include <asm/cacheflush.h>
  34 #include <asm/asm-offsets.h>
  35
  36 #ifdef CONFIG_COMPAT
  37 #include "signal32.h"
  38 #endif
  39
  40 #define DEBUG_SIG 0
  41 #define DEBUG_SIG_LEVEL 2
  42
  43 #if DEBUG_SIG
  44 #define DBG(LEVEL, ...) \
  45         ((DEBUG_SIG_LEVEL >= LEVEL) \
  46         ? printk(__VA_ARGS__) : (void) 0)
  47 #else
  48 #define DBG(LEVEL, ...)
  49 #endif
  50
  51 /* gcc will complain if a pointer is cast to an integer of different
  52  * size.  If you really need to do this (and we do for an ELF32 user
  53  * application in an ELF64 kernel) then you have to do a cast to an
  54  * integer of the same size first.  The A() macro accomplishes
  55  * this. */
  56 #define A(__x)  ((unsigned long)(__x))
  57
  58 /*
  59  * Do a signal return - restore sigcontext.
  60  */
  61
  62 /* Trampoline for calling rt_sigreturn() */
  63 #define INSN_LDI_R25_0   0x34190000 /* ldi  0,%r25 (in_syscall=0) */
  64 #define INSN_LDI_R25_1   0x34190002 /* ldi  1,%r25 (in_syscall=1) */
  65 #define INSN_LDI_R20     0x3414015a /* ldi  __NR_rt_sigreturn,%r20 */
  66 #define INSN_BLE_SR2_R0  0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */
  67 /* For debugging */
  68 #define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */
  69
  70 static long
  71 restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
  72 {
  73         long err = 0;
  74
  75         err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr));
  76         err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr));
  77         err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq));
  78         err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq));
  79         err |= __get_user(regs->sar, &sc->sc_sar);
  80         DBG(2,"restore_sigcontext: iaoq is %#lx / %#lx\n",
  81                         regs->iaoq[0],regs->iaoq[1]);
  82         DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]);
  83         return err;
  84 }
  85
  86 void
  87 sys_rt_sigreturn(struct pt_regs *regs, int in_syscall)
  88 {
  89         struct rt_sigframe __user *frame;
  90         sigset_t set;
  91         unsigned long usp = (regs->gr[30] & ~(0x01UL));
  92         unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE;
  93 #ifdef CONFIG_64BIT
  94         struct compat_rt_sigframe __user * compat_frame;
  95
  96         if (is_compat_task())
  97                 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
  98 #endif
  99
 100         current->restart_block.fn = do_no_restart_syscall;
 101
 102         /* Unwind the user stack to get the rt_sigframe structure. */
 103         frame = (struct rt_sigframe __user *)
 104                 (usp - sigframe_size);
 105         DBG(2,"sys_rt_sigreturn: frame is %p\n", frame);
 106
 107         regs->orig_r28 = 1; /* no restarts for sigreturn */
 108
 109 #ifdef CONFIG_64BIT
 110         compat_frame = (struct compat_rt_sigframe __user *)frame;
 111
 112         if (is_compat_task()) {
 113                 DBG(2,"sys_rt_sigreturn: ELF32 process.\n");
 114                 if (get_compat_sigset(&set, &compat_frame->uc.uc_sigmask))
 115                         goto give_sigsegv;
 116         } else
 117 #endif
 118         {
 119                 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 120                         goto give_sigsegv;
 121         }
 122
 123         set_current_blocked(&set);
 124
 125         /* Good thing we saved the old gr[30], eh? */
 126 #ifdef CONFIG_64BIT
 127         if (is_compat_task()) {
 128                 DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n",
 129                                 &compat_frame->uc.uc_mcontext);
 130 // FIXME: Load upper half from register file
 131                 if (restore_sigcontext32(&compat_frame->uc.uc_mcontext,
 132                                         &compat_frame->regs, regs))
 133                         goto give_sigsegv;
 134                 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
 135                                 usp, &compat_frame->uc.uc_stack);
 136                 if (compat_restore_altstack(&compat_frame->uc.uc_stack))
 137                         goto give_sigsegv;
 138         } else
 139 #endif
 140         {
 141                 DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n",
 142                                 &frame->uc.uc_mcontext);
 143                 if (restore_sigcontext(&frame->uc.uc_mcontext, regs))
 144                         goto give_sigsegv;
 145                 DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n",
 146                                 usp, &frame->uc.uc_stack);
 147                 if (restore_altstack(&frame->uc.uc_stack))
 148                         goto give_sigsegv;
 149         }
 150
 151
 152
 153         /* If we are on the syscall path IAOQ will not be restored, and
 154          * if we are on the interrupt path we must not corrupt gr31.
 155          */
 156         if (in_syscall)
 157                 regs->gr[31] = regs->iaoq[0];
 158 #if DEBUG_SIG
 159         DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]);
 160         show_regs(regs);
 161 #endif
 162         return;
 163
 164 give_sigsegv:
 165         DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n");
 166         force_sig(SIGSEGV);
 167         return;
 168 }
 169
 170 /*
 171  * Set up a signal frame.
 172  */
 173
 174 static inline void __user *
 175 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
 176 {
 177         /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we
 178           don't use the parameter it doesn't matter */
 179
 180         DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n",
 181                         (unsigned long)ka, sp, frame_size);
 182
 183         /* Align alternate stack and reserve 64 bytes for the signal
 184            handler's frame marker.  */
 185         if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp))
 186                 sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */
 187
 188         DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp);
 189         return (void __user *) sp; /* Stacks grow up.  Fun. */
 190 }
 191
 192 static long
 193 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall)
 194
 195 {
 196         unsigned long flags = 0;
 197         long err = 0;
 198
 199         if (on_sig_stack((unsigned long) sc))
 200                 flags |= PARISC_SC_FLAG_ONSTACK;
 201         if (in_syscall) {
 202                 flags |= PARISC_SC_FLAG_IN_SYSCALL;
 203                 /* regs->iaoq is undefined in the syscall return path */
 204                 err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]);
 205                 err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]);
 206                 err |= __put_user(regs->sr[3], &sc->sc_iasq[0]);
 207                 err |= __put_user(regs->sr[3], &sc->sc_iasq[1]);
 208                 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n",
 209                         regs->gr[31], regs->gr[31]+4);
 210         } else {
 211                 err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq));
 212                 err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq));
 213                 DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n",
 214                         regs->iaoq[0], regs->iaoq[1]);
 215         }
 216
 217         err |= __put_user(flags, &sc->sc_flags);
 218         err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr));
 219         err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr));
 220         err |= __put_user(regs->sar, &sc->sc_sar);
 221         DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]);
 222
 223         return err;
 224 }
 225
 226 static long
 227 setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs,
 228                int in_syscall)
 229 {
 230         struct rt_sigframe __user *frame;
 231         unsigned long rp, usp;
 232         unsigned long haddr, sigframe_size;
 233         unsigned long start, end;
 234         int err = 0;
 235 #ifdef CONFIG_64BIT
 236         struct compat_rt_sigframe __user * compat_frame;
 237 #endif
 238
 239         usp = (regs->gr[30] & ~(0x01UL));
 240         /*FIXME: frame_size parameter is unused, remove it. */
 241         frame = get_sigframe(&ksig->ka, usp, sizeof(*frame));
 242
 243         DBG(1,"SETUP_RT_FRAME: START\n");
 244         DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info);
 245
 246
 247 #ifdef CONFIG_64BIT
 248
 249         compat_frame = (struct compat_rt_sigframe __user *)frame;
 250
 251         if (is_compat_task()) {
 252                 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info);
 253                 err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info);
 254                 err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]);
 255                 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc);
 256                 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext);
 257                 err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext,
 258                                         &compat_frame->regs, regs, in_syscall);
 259                 err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set,
 260                                          sizeof(compat_sigset_t));
 261         } else
 262 #endif
 263         {
 264                 DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info);
 265                 err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 266                 err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]);
 267                 DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc);
 268                 DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext);
 269                 err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall);
 270                 /* FIXME: Should probably be converted as well for the compat case */
 271                 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 272         }
 273
 274         if (err)
 275                 return -EFAULT;
 276
 277         /* Set up to return from userspace.  If provided, use a stub
 278            already in userspace. The first words of tramp are used to
 279            save the previous sigrestartblock trampoline that might be
 280            on the stack. We start the sigreturn trampoline at
 281            SIGRESTARTBLOCK_TRAMP+X. */
 282         err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0,
 283                         &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]);
 284         err |= __put_user(INSN_LDI_R20,
 285                         &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]);
 286         err |= __put_user(INSN_BLE_SR2_R0,
 287                         &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]);
 288         err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]);
 289
 290 #if DEBUG_SIG
 291         /* Assert that we're flushing in the correct space... */
 292         {
 293                 unsigned long sid;
 294                 asm ("mfsp %%sr3,%0" : "=r" (sid));
 295                 DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n",
 296                        sid, frame->tramp);
 297         }
 298 #endif
 299
 300         start = (unsigned long) &frame->tramp[0];
 301         end = (unsigned long) &frame->tramp[TRAMP_SIZE];
 302         flush_user_dcache_range_asm(start, end);
 303         flush_user_icache_range_asm(start, end);
 304
 305         /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP
 306          * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP
 307          * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP
 308          */
 309         rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP];
 310
 311         if (err)
 312                 return -EFAULT;
 313
 314         haddr = A(ksig->ka.sa.sa_handler);
 315         /* The sa_handler may be a pointer to a function descriptor */
 316 #ifdef CONFIG_64BIT
 317         if (is_compat_task()) {
 318 #endif
 319                 if (haddr & PA_PLABEL_FDESC) {
 320                         Elf32_Fdesc fdesc;
 321                         Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3);
 322
 323                         err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
 324
 325                         if (err)
 326                                 return -EFAULT;
 327
 328                         haddr = fdesc.addr;
 329                         regs->gr[19] = fdesc.gp;
 330                 }
 331 #ifdef CONFIG_64BIT
 332         } else {
 333                 Elf64_Fdesc fdesc;
 334                 Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3);
 335
 336                 err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc));
 337
 338                 if (err)
 339                         return -EFAULT;
 340
 341                 haddr = fdesc.addr;
 342                 regs->gr[19] = fdesc.gp;
 343                 DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n",
 344                      haddr, regs->gr[19], in_syscall);
 345         }
 346 #endif
 347
 348         /* The syscall return path will create IAOQ values from r31.
 349          */
 350         sigframe_size = PARISC_RT_SIGFRAME_SIZE;
 351 #ifdef CONFIG_64BIT
 352         if (is_compat_task())
 353                 sigframe_size = PARISC_RT_SIGFRAME_SIZE32;
 354 #endif
 355         if (in_syscall) {
 356                 regs->gr[31] = haddr;
 357 #ifdef CONFIG_64BIT
 358                 if (!test_thread_flag(TIF_32BIT))
 359                         sigframe_size |= 1;
 360 #endif
 361         } else {
 362                 unsigned long psw = USER_PSW;
 363 #ifdef CONFIG_64BIT
 364                 if (!test_thread_flag(TIF_32BIT))
 365                         psw |= PSW_W;
 366 #endif
 367
 368                 /* If we are singlestepping, arrange a trap to be delivered
 369                    when we return to userspace. Note the semantics -- we
 370                    should trap before the first insn in the handler is
 371                    executed. Ref:
 372                         http://sources.redhat.com/ml/gdb/2004-11/msg00245.html
 373                  */
 374                 if (pa_psw(current)->r) {
 375                         pa_psw(current)->r = 0;
 376                         psw |= PSW_R;
 377                         mtctl(-1, 0);
 378                 }
 379
 380                 regs->gr[0] = psw;
 381                 regs->iaoq[0] = haddr | 3;
 382                 regs->iaoq[1] = regs->iaoq[0] + 4;
 383         }
 384
 385         regs->gr[2]  = rp;                /* userland return pointer */
 386         regs->gr[26] = ksig->sig;               /* signal number */
 387
 388 #ifdef CONFIG_64BIT
 389         if (is_compat_task()) {
 390                 regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */
 391                 regs->gr[24] = A(&compat_frame->uc);   /* ucontext pointer */
 392         } else
 393 #endif
 394         {
 395                 regs->gr[25] = A(&frame->info); /* siginfo pointer */
 396                 regs->gr[24] = A(&frame->uc);   /* ucontext pointer */
 397         }
 398
 399         DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n",
 400                regs->gr[30], sigframe_size,
 401                regs->gr[30] + sigframe_size);
 402         /* Raise the user stack pointer to make a proper call frame. */
 403         regs->gr[30] = (A(frame) + sigframe_size);
 404
 405
 406         DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n",
 407                current->comm, current->pid, frame, regs->gr[30],
 408                regs->iaoq[0], regs->iaoq[1], rp);
 409
 410         return 0;
 411 }
 412
 413 /*
 414  * OK, we're invoking a handler.
 415  */
 416
 417 static void
 418 handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall)
 419 {
 420         int ret;
 421         sigset_t *oldset = sigmask_to_save();
 422
 423         DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n",
 424                ksig->sig, ksig->ka, ksig->info, oldset, regs);
 425
 426         /* Set up the stack frame */
 427         ret = setup_rt_frame(ksig, oldset, regs, in_syscall);
 428
 429         signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) ||
 430                           test_thread_flag(TIF_BLOCKSTEP));
 431
 432         DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n",
 433                 regs->gr[28]);
 434 }
 435
 436 /*
 437  * Check how the syscall number gets loaded into %r20 within
 438  * the delay branch in userspace and adjust as needed.
 439  */
 440
 441 static void check_syscallno_in_delay_branch(struct pt_regs *regs)
 442 {
 443         u32 opcode, source_reg;
 444         u32 __user *uaddr;
 445         int err;
 446
 447         /* Usually we don't have to restore %r20 (the system call number)
 448          * because it gets loaded in the delay slot of the branch external
 449          * instruction via the ldi instruction.
 450          * In some cases a register-to-register copy instruction might have
 451          * been used instead, in which case we need to copy the syscall
 452          * number into the source register before returning to userspace.
 453          */
 454
 455         /* A syscall is just a branch, so all we have to do is fiddle the
 456          * return pointer so that the ble instruction gets executed again.
 457          */
 458         regs->gr[31] -= 8; /* delayed branching */
 459
 460         /* Get assembler opcode of code in delay branch */
 461         uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4);
 462         err = get_user(opcode, uaddr);
 463         if (err)
 464                 return;
 465
 466         /* Check if delay branch uses "ldi int,%r20" */
 467         if ((opcode & 0xffff0000) == 0x34140000)
 468                 return; /* everything ok, just return */
 469
 470         /* Check if delay branch uses "nop" */
 471         if (opcode == INSN_NOP)
 472                 return;
 473
 474         /* Check if delay branch uses "copy %rX,%r20" */
 475         if ((opcode & 0xffe0ffff) == 0x08000254) {
 476                 source_reg = (opcode >> 16) & 31;
 477                 regs->gr[source_reg] = regs->gr[20];
 478                 return;
 479         }
 480
 481         pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n",
 482                 current->comm, task_pid_nr(current), opcode);
 483 }
 484
 485 static inline void
 486 syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
 487 {
 488         if (regs->orig_r28)
 489                 return;
 490         regs->orig_r28 = 1; /* no more restarts */
 491         /* Check the return code */
 492         switch (regs->gr[28]) {
 493         case -ERESTART_RESTARTBLOCK:
 494         case -ERESTARTNOHAND:
 495                 DBG(1,"ERESTARTNOHAND: returning -EINTR\n");
 496                 regs->gr[28] = -EINTR;
 497                 break;
 498
 499         case -ERESTARTSYS:
 500                 if (!(ka->sa.sa_flags & SA_RESTART)) {
 501                         DBG(1,"ERESTARTSYS: putting -EINTR\n");
 502                         regs->gr[28] = -EINTR;
 503                         break;
 504                 }
 505                 fallthrough;
 506         case -ERESTARTNOINTR:
 507                 check_syscallno_in_delay_branch(regs);
 508                 break;
 509         }
 510 }
 511
 512 static inline void
 513 insert_restart_trampoline(struct pt_regs *regs)
 514 {
 515         if (regs->orig_r28)
 516                 return;
 517         regs->orig_r28 = 1; /* no more restarts */
 518         switch(regs->gr[28]) {
 519         case -ERESTART_RESTARTBLOCK: {
 520                 /* Restart the system call - no handlers present */
 521                 unsigned int *usp = (unsigned int *)regs->gr[30];
 522                 unsigned long start = (unsigned long) &usp[2];
 523                 unsigned long end  = (unsigned long) &usp[5];
 524                 long err = 0;
 525
 526                 /* Setup a trampoline to restart the syscall
 527                  * with __NR_restart_syscall
 528                  *
 529                  *  0: <return address (orig r31)>
 530                  *  4: <2nd half for 64-bit>
 531                  *  8: ldw 0(%sp), %r31
 532                  * 12: be 0x100(%sr2, %r0)
 533                  * 16: ldi __NR_restart_syscall, %r20
 534                  */
 535 #ifdef CONFIG_64BIT
 536                 err |= put_user(regs->gr[31] >> 32, &usp[0]);
 537                 err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]);
 538                 err |= put_user(0x0fc010df, &usp[2]);
 539 #else
 540                 err |= put_user(regs->gr[31], &usp[0]);
 541                 err |= put_user(0x0fc0109f, &usp[2]);
 542 #endif
 543                 err |= put_user(0xe0008200, &usp[3]);
 544                 err |= put_user(0x34140000, &usp[4]);
 545
 546                 WARN_ON(err);
 547
 548                 /* flush data/instruction cache for new insns */
 549                 flush_user_dcache_range_asm(start, end);
 550                 flush_user_icache_range_asm(start, end);
 551
 552                 regs->gr[31] = regs->gr[30] + 8;
 553                 return;
 554         }
 555         case -ERESTARTNOHAND:
 556         case -ERESTARTSYS:
 557         case -ERESTARTNOINTR:
 558                 check_syscallno_in_delay_branch(regs);
 559                 return;
 560         default:
 561                 break;
 562         }
 563 }
 564
 565 /*
 566  * Note that 'init' is a special process: it doesn't get signals it doesn't
 567  * want to handle. Thus you cannot kill init even with a SIGKILL even by
 568  * mistake.
 569  *
 570  * We need to be able to restore the syscall arguments (r21-r26) to
 571  * restart syscalls.  Thus, the syscall path should save them in the
 572  * pt_regs structure (it's okay to do so since they are caller-save
 573  * registers).  As noted below, the syscall number gets restored for
 574  * us due to the magic of delayed branching.
 575  */
 576 asmlinkage void
 577 do_signal(struct pt_regs *regs, long in_syscall)
 578 {
 579         struct ksignal ksig;
 580
 581         DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n",
 582                regs, regs->sr[7], in_syscall);
 583
 584         if (get_signal(&ksig)) {
 585                 DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]);
 586                 /* Restart a system call if necessary. */
 587                 if (in_syscall)
 588                         syscall_restart(regs, &ksig.ka);
 589
 590                 handle_signal(&ksig, regs, in_syscall);
 591                 return;
 592         }
 593
 594         /* Did we come from a system call? */
 595         if (in_syscall)
 596                 insert_restart_trampoline(regs);
 597
 598         DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n",
 599                 regs->gr[28]);
 600
 601         restore_saved_sigmask();
 602 }
 603
 604 void do_notify_resume(struct pt_regs *regs, long in_syscall)
 605 {
 606         if (test_thread_flag(TIF_SIGPENDING) ||
 607             test_thread_flag(TIF_NOTIFY_SIGNAL))
 608                 do_signal(regs, in_syscall);
 609
 610         if (test_thread_flag(TIF_NOTIFY_RESUME))
 611                 tracehook_notify_resume(regs);
 612 }