1/* 2 * linux/arch/arm/kernel/signal.c 3 * 4 * Copyright (C) 1995-2002 Russell King 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10#include <linux/errno.h> 11#include <linux/signal.h> 12#include <linux/personality.h> 13#include <linux/freezer.h> 14 15#include <asm/elf.h> 16#include <asm/cacheflush.h> 17#include <asm/ucontext.h> 18#include <asm/uaccess.h> 19#include <asm/unistd.h> 20 21#include "ptrace.h" 22#include "signal.h" 23 24#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 25 26/* 27 * For ARM syscalls, we encode the syscall number into the instruction. 28 */ 29#define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)) 30#define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)) 31 32/* 33 * With EABI, the syscall number has to be loaded into r7. 34 */ 35#define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE)) 36#define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) 37 38/* 39 * For Thumb syscalls, we pass the syscall number via r7. We therefore 40 * need two 16-bit instructions. 41 */ 42#define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE)) 43#define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) 44 45const unsigned long sigreturn_codes[7] = { 46 MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, 47 MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN, 48}; 49 50static int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall); 51 52/* 53 * atomically swap in the new signal mask, and wait for a signal. 54 */ 55asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, struct pt_regs *regs) 56{ 57 sigset_t saveset; 58 59 mask &= _BLOCKABLE; 60 spin_lock_irq(¤t->sighand->siglock); 61 saveset = current->blocked; 62 siginitset(¤t->blocked, mask); 63 recalc_sigpending(); 64 spin_unlock_irq(¤t->sighand->siglock); 65 regs->ARM_r0 = -EINTR; 66 67 while (1) { 68 current->state = TASK_INTERRUPTIBLE; 69 schedule(); 70 if (do_signal(&saveset, regs, 0)) 71 return regs->ARM_r0; 72 } 73} 74 75asmlinkage int 76sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, struct pt_regs *regs) 77{ 78 sigset_t saveset, newset; 79 80 if (sigsetsize != sizeof(sigset_t)) 81 return -EINVAL; 82 83 if (copy_from_user(&newset, unewset, sizeof(newset))) 84 return -EFAULT; 85 sigdelsetmask(&newset, ~_BLOCKABLE); 86 87 spin_lock_irq(¤t->sighand->siglock); 88 saveset = current->blocked; 89 current->blocked = newset; 90 recalc_sigpending(); 91 spin_unlock_irq(¤t->sighand->siglock); 92 regs->ARM_r0 = -EINTR; 93 94 while (1) { 95 current->state = TASK_INTERRUPTIBLE; 96 schedule(); 97 if (do_signal(&saveset, regs, 0)) 98 return regs->ARM_r0; 99 } 100} 101 102asmlinkage int 103sys_sigaction(int sig, const struct old_sigaction __user *act, 104 struct old_sigaction __user *oact) 105{ 106 struct k_sigaction new_ka, old_ka; 107 int ret; 108 109 if (act) { 110 old_sigset_t mask; 111 if (!access_ok(VERIFY_READ, act, sizeof(*act)) || 112 __get_user(new_ka.sa.sa_handler, &act->sa_handler) || 113 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) 114 return -EFAULT; 115 __get_user(new_ka.sa.sa_flags, &act->sa_flags); 116 __get_user(mask, &act->sa_mask); 117 siginitset(&new_ka.sa.sa_mask, mask); 118 } 119 120 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 121 122 if (!ret && oact) { 123 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || 124 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || 125 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) 126 return -EFAULT; 127 __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 128 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); 129 } 130 131 return ret; 132} 133 134#ifdef CONFIG_CRUNCH 135static int preserve_crunch_context(struct crunch_sigframe *frame) 136{ 137 char kbuf[sizeof(*frame) + 8]; 138 struct crunch_sigframe *kframe; 139 140 /* the crunch context must be 64 bit aligned */ 141 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 142 kframe->magic = CRUNCH_MAGIC; 143 kframe->size = CRUNCH_STORAGE_SIZE; 144 crunch_task_copy(current_thread_info(), &kframe->storage); 145 return __copy_to_user(frame, kframe, sizeof(*frame)); 146} 147 148static int restore_crunch_context(struct crunch_sigframe *frame) 149{ 150 char kbuf[sizeof(*frame) + 8]; 151 struct crunch_sigframe *kframe; 152 153 /* the crunch context must be 64 bit aligned */ 154 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 155 if (__copy_from_user(kframe, frame, sizeof(*frame))) 156 return -1; 157 if (kframe->magic != CRUNCH_MAGIC || 158 kframe->size != CRUNCH_STORAGE_SIZE) 159 return -1; 160 crunch_task_restore(current_thread_info(), &kframe->storage); 161 return 0; 162} 163#endif 164 165#ifdef CONFIG_IWMMXT 166 167static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame) 168{ 169 char kbuf[sizeof(*frame) + 8]; 170 struct iwmmxt_sigframe *kframe; 171 172 /* the iWMMXt context must be 64 bit aligned */ 173 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 174 kframe->magic = IWMMXT_MAGIC; 175 kframe->size = IWMMXT_STORAGE_SIZE; 176 iwmmxt_task_copy(current_thread_info(), &kframe->storage); 177 return __copy_to_user(frame, kframe, sizeof(*frame)); 178} 179 180static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame) 181{ 182 char kbuf[sizeof(*frame) + 8]; 183 struct iwmmxt_sigframe *kframe; 184 185 /* the iWMMXt context must be 64 bit aligned */ 186 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 187 if (__copy_from_user(kframe, frame, sizeof(*frame))) 188 return -1; 189 if (kframe->magic != IWMMXT_MAGIC || 190 kframe->size != IWMMXT_STORAGE_SIZE) 191 return -1; 192 iwmmxt_task_restore(current_thread_info(), &kframe->storage); 193 return 0; 194} 195 196#endif 197 198/* 199 * Do a signal return; undo the signal stack. These are aligned to 64-bit. 200 */ 201struct sigframe { 202 struct ucontext uc; 203 unsigned long retcode[2]; 204}; 205 206struct rt_sigframe { 207 struct siginfo info; 208 struct sigframe sig; 209}; 210 211static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) 212{ 213 struct aux_sigframe __user *aux; 214 sigset_t set; 215 int err; 216 217 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); 218 if (err == 0) { 219 sigdelsetmask(&set, ~_BLOCKABLE); 220 spin_lock_irq(¤t->sighand->siglock); 221 current->blocked = set; 222 recalc_sigpending(); 223 spin_unlock_irq(¤t->sighand->siglock); 224 } 225 226 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 227 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 228 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 229 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 230 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 231 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 232 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 233 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 234 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 235 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 236 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 237 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 238 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 239 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 240 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 241 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 242 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 243 244 err |= !valid_user_regs(regs); 245 246 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 247#ifdef CONFIG_CRUNCH 248 if (err == 0) 249 err |= restore_crunch_context(&aux->crunch); 250#endif 251#ifdef CONFIG_IWMMXT 252 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 253 err |= restore_iwmmxt_context(&aux->iwmmxt); 254#endif 255#ifdef CONFIG_VFP 256// if (err == 0) 257// err |= vfp_restore_state(&sf->aux.vfp); 258#endif 259 260 return err; 261} 262 263asmlinkage int sys_sigreturn(struct pt_regs *regs) 264{ 265 struct sigframe __user *frame; 266 267 /* Always make any pending restarted system calls return -EINTR */ 268 current_thread_info()->restart_block.fn = do_no_restart_syscall; 269 270 /* 271 * Since we stacked the signal on a 64-bit boundary, 272 * then 'sp' should be word aligned here. If it's 273 * not, then the user is trying to mess with us. 274 */ 275 if (regs->ARM_sp & 7) 276 goto badframe; 277 278 frame = (struct sigframe __user *)regs->ARM_sp; 279 280 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 281 goto badframe; 282 283 if (restore_sigframe(regs, frame)) 284 goto badframe; 285 286 single_step_trap(current); 287 288 return regs->ARM_r0; 289 290badframe: 291 force_sig(SIGSEGV, current); 292 return 0; 293} 294 295asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) 296{ 297 struct rt_sigframe __user *frame; 298 299 /* Always make any pending restarted system calls return -EINTR */ 300 current_thread_info()->restart_block.fn = do_no_restart_syscall; 301 302 /* 303 * Since we stacked the signal on a 64-bit boundary, 304 * then 'sp' should be word aligned here. If it's 305 * not, then the user is trying to mess with us. 306 */ 307 if (regs->ARM_sp & 7) 308 goto badframe; 309 310 frame = (struct rt_sigframe __user *)regs->ARM_sp; 311 312 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 313 goto badframe; 314 315 if (restore_sigframe(regs, &frame->sig)) 316 goto badframe; 317 318 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT) 319 goto badframe; 320 321 single_step_trap(current); 322 323 return regs->ARM_r0; 324 325badframe: 326 force_sig(SIGSEGV, current); 327 return 0; 328} 329 330static int 331setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) 332{ 333 struct aux_sigframe __user *aux; 334 int err = 0; 335 336 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 337 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 338 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 339 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 340 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 341 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 342 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 343 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 344 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 345 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 346 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 347 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 348 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 349 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 350 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 351 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 352 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 353 354 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err); 355 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err); 356 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err); 357 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 358 359 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); 360 361 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 362#ifdef CONFIG_CRUNCH 363 if (err == 0) 364 err |= preserve_crunch_context(&aux->crunch); 365#endif 366#ifdef CONFIG_IWMMXT 367 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 368 err |= preserve_iwmmxt_context(&aux->iwmmxt); 369#endif 370#ifdef CONFIG_VFP 371// if (err == 0) 372// err |= vfp_save_state(&sf->aux.vfp); 373#endif 374 __put_user_error(0, &aux->end_magic, err); 375 376 return err; 377} 378 379static inline void __user * 380get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) 381{ 382 unsigned long sp = regs->ARM_sp; 383 void __user *frame; 384 385 /* 386 * This is the X/Open sanctioned signal stack switching. 387 */ 388 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) 389 sp = current->sas_ss_sp + current->sas_ss_size; 390 391 /* 392 * ATPCS B01 mandates 8-byte alignment 393 */ 394 frame = (void __user *)((sp - framesize) & ~7); 395 396 /* 397 * Check that we can actually write to the signal frame. 398 */ 399 if (!access_ok(VERIFY_WRITE, frame, framesize)) 400 frame = NULL; 401 402 return frame; 403} 404 405static int 406setup_return(struct pt_regs *regs, struct k_sigaction *ka, 407 unsigned long __user *rc, void __user *frame, int usig) 408{ 409 unsigned long handler = (unsigned long)ka->sa.sa_handler; 410 unsigned long retcode; 411 int thumb = 0; 412 unsigned long cpsr = regs->ARM_cpsr & ~PSR_f; 413 414 /* 415 * Maybe we need to deliver a 32-bit signal to a 26-bit task. 416 */ 417 if (ka->sa.sa_flags & SA_THIRTYTWO) 418 cpsr = (cpsr & ~MODE_MASK) | USR_MODE; 419 420#ifdef CONFIG_ARM_THUMB 421 if (elf_hwcap & HWCAP_THUMB) { 422 /* 423 * The LSB of the handler determines if we're going to 424 * be using THUMB or ARM mode for this signal handler. 425 */ 426 thumb = handler & 1; 427 428 if (thumb) 429 cpsr |= PSR_T_BIT; 430 else 431 cpsr &= ~PSR_T_BIT; 432 } 433#endif 434 435 if (ka->sa.sa_flags & SA_RESTORER) { 436 retcode = (unsigned long)ka->sa.sa_restorer; 437 } else { 438 unsigned int idx = thumb << 1; 439 440 if (ka->sa.sa_flags & SA_SIGINFO) 441 idx += 3; 442 443 if (__put_user(sigreturn_codes[idx], rc) || 444 __put_user(sigreturn_codes[idx+1], rc+1)) 445 return 1; 446 447 if (cpsr & MODE32_BIT) { 448 /* 449 * 32-bit code can use the new high-page 450 * signal return code support. 451 */ 452 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; 453 } else { 454 /* 455 * Ensure that the instruction cache sees 456 * the return code written onto the stack. 457 */ 458 flush_icache_range((unsigned long)rc, 459 (unsigned long)(rc + 2)); 460 461 retcode = ((unsigned long)rc) + thumb; 462 } 463 } 464 465 regs->ARM_r0 = usig; 466 regs->ARM_sp = (unsigned long)frame; 467 regs->ARM_lr = retcode; 468 regs->ARM_pc = handler; 469 regs->ARM_cpsr = cpsr; 470 471 return 0; 472} 473 474static int 475setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) 476{ 477 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 478 int err = 0; 479 480 if (!frame) 481 return 1; 482 483 /* 484 * Set uc.uc_flags to a value which sc.trap_no would never have. 485 */ 486 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 487 488 err |= setup_sigframe(frame, regs, set); 489 if (err == 0) 490 err = setup_return(regs, ka, frame->retcode, frame, usig); 491 492 return err; 493} 494 495static int 496setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, 497 sigset_t *set, struct pt_regs *regs) 498{ 499 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 500 stack_t stack; 501 int err = 0; 502 503 if (!frame) 504 return 1; 505 506 err |= copy_siginfo_to_user(&frame->info, info); 507 508 __put_user_error(0, &frame->sig.uc.uc_flags, err); 509 __put_user_error(NULL, &frame->sig.uc.uc_link, err); 510 511 memset(&stack, 0, sizeof(stack)); 512 stack.ss_sp = (void __user *)current->sas_ss_sp; 513 stack.ss_flags = sas_ss_flags(regs->ARM_sp); 514 stack.ss_size = current->sas_ss_size; 515 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack)); 516 517 err |= setup_sigframe(&frame->sig, regs, set); 518 if (err == 0) 519 err = setup_return(regs, ka, frame->sig.retcode, frame, usig); 520 521 if (err == 0) { 522 /* 523 * For realtime signals we must also set the second and third 524 * arguments for the signal handler. 525 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 526 */ 527 regs->ARM_r1 = (unsigned long)&frame->info; 528 regs->ARM_r2 = (unsigned long)&frame->sig.uc; 529 } 530 531 return err; 532} 533 534static inline void restart_syscall(struct pt_regs *regs) 535{ 536 regs->ARM_r0 = regs->ARM_ORIG_r0; 537 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 538} 539 540/* 541 * OK, we're invoking a handler 542 */ 543static void 544handle_signal(unsigned long sig, struct k_sigaction *ka, 545 siginfo_t *info, sigset_t *oldset, 546 struct pt_regs * regs, int syscall) 547{ 548 struct thread_info *thread = current_thread_info(); 549 struct task_struct *tsk = current; 550 int usig = sig; 551 int ret; 552 553 /* 554 * If we were from a system call, check for system call restarting... 555 */ 556 if (syscall) { 557 switch (regs->ARM_r0) { 558 case -ERESTART_RESTARTBLOCK: 559 case -ERESTARTNOHAND: 560 regs->ARM_r0 = -EINTR; 561 break; 562 case -ERESTARTSYS: 563 if (!(ka->sa.sa_flags & SA_RESTART)) { 564 regs->ARM_r0 = -EINTR; 565 break; 566 } 567 /* fallthrough */ 568 case -ERESTARTNOINTR: 569 restart_syscall(regs); 570 } 571 } 572 573 /* 574 * translate the signal 575 */ 576 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap) 577 usig = thread->exec_domain->signal_invmap[usig]; 578 579 /* 580 * Set up the stack frame 581 */ 582 if (ka->sa.sa_flags & SA_SIGINFO) 583 ret = setup_rt_frame(usig, ka, info, oldset, regs); 584 else 585 ret = setup_frame(usig, ka, oldset, regs); 586 587 /* 588 * Check that the resulting registers are actually sane. 589 */ 590 ret |= !valid_user_regs(regs); 591 592 if (ret != 0) { 593 force_sigsegv(sig, tsk); 594 return; 595 } 596 597 /* 598 * Block the signal if we were successful. 599 */ 600 spin_lock_irq(&tsk->sighand->siglock); 601 sigorsets(&tsk->blocked, &tsk->blocked, 602 &ka->sa.sa_mask); 603 if (!(ka->sa.sa_flags & SA_NODEFER)) 604 sigaddset(&tsk->blocked, sig); 605 recalc_sigpending(); 606 spin_unlock_irq(&tsk->sighand->siglock); 607 608} 609 610/* 611 * Note that 'init' is a special process: it doesn't get signals it doesn't 612 * want to handle. Thus you cannot kill init even with a SIGKILL even by 613 * mistake. 614 * 615 * Note that we go through the signals twice: once to check the signals that 616 * the kernel can handle, and then we build all the user-level signal handling 617 * stack-frames in one go after that. 618 */ 619static int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall) 620{ 621 struct k_sigaction ka; 622 siginfo_t info; 623 int signr; 624 625 /* 626 * We want the common case to go fast, which 627 * is why we may in certain cases get here from 628 * kernel mode. Just return without doing anything 629 * if so. 630 */ 631 if (!user_mode(regs)) 632 return 0; 633 634 if (try_to_freeze()) 635 goto no_signal; 636 637 single_step_clear(current); 638 639 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 640 if (signr > 0) { 641 handle_signal(signr, &ka, &info, oldset, regs, syscall); 642 single_step_set(current); 643 return 1; 644 } 645 646 no_signal: 647 /* 648 * No signal to deliver to the process - restart the syscall. 649 */ 650 if (syscall) { 651 if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) { 652 if (thumb_mode(regs)) { 653 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; 654 regs->ARM_pc -= 2; 655 } else { 656#if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT) 657 regs->ARM_r7 = __NR_restart_syscall; 658 regs->ARM_pc -= 4; 659#else 660 u32 __user *usp; 661 u32 swival = __NR_restart_syscall; 662 663 regs->ARM_sp -= 12; 664 usp = (u32 __user *)regs->ARM_sp; 665 666 /* 667 * Either we supports OABI only, or we have 668 * EABI with the OABI compat layer enabled. 669 * In the later case we don't know if user 670 * space is EABI or not, and if not we must 671 * not clobber r7. Always using the OABI 672 * syscall solves that issue and works for 673 * all those cases. 674 */ 675 swival = swival - __NR_SYSCALL_BASE + __NR_OABI_SYSCALL_BASE; 676 677 put_user(regs->ARM_pc, &usp[0]); 678 /* swi __NR_restart_syscall */ 679 put_user(0xef000000 | swival, &usp[1]); 680 /* ldr pc, [sp], #12 */ 681 put_user(0xe49df00c, &usp[2]); 682 683 flush_icache_range((unsigned long)usp, 684 (unsigned long)(usp + 3)); 685 686 regs->ARM_pc = regs->ARM_sp + 4; 687#endif 688 } 689 } 690 if (regs->ARM_r0 == -ERESTARTNOHAND || 691 regs->ARM_r0 == -ERESTARTSYS || 692 regs->ARM_r0 == -ERESTARTNOINTR) { 693 restart_syscall(regs); 694 } 695 } 696 single_step_set(current); 697 return 0; 698} 699 700asmlinkage void 701do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) 702{ 703 if (thread_flags & _TIF_SIGPENDING) 704 do_signal(¤t->blocked, regs, syscall); 705} 706