1 /* 2 * linux/arch/arm/kernel/signal.c 3 * 4 * Copyright (C) 1995-2009 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 #include <linux/uaccess.h> 15 #include <linux/tracehook.h> 16 17 #include <asm/elf.h> 18 #include <asm/cacheflush.h> 19 #include <asm/ucontext.h> 20 #include <asm/unistd.h> 21 #include <asm/vfp.h> 22 23 #include "ptrace.h" 24 #include "signal.h" 25 26 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) 27 28 /* 29 * For ARM syscalls, we encode the syscall number into the instruction. 30 */ 31 #define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE)) 32 #define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE)) 33 #define SWI_SYS_RESTART (0xef000000|__NR_restart_syscall|__NR_OABI_SYSCALL_BASE) 34 35 /* 36 * With EABI, the syscall number has to be loaded into r7. 37 */ 38 #define MOV_R7_NR_SIGRETURN (0xe3a07000 | (__NR_sigreturn - __NR_SYSCALL_BASE)) 39 #define MOV_R7_NR_RT_SIGRETURN (0xe3a07000 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) 40 41 /* 42 * For Thumb syscalls, we pass the syscall number via r7. We therefore 43 * need two 16-bit instructions. 44 */ 45 #define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE)) 46 #define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE)) 47 48 const unsigned long sigreturn_codes[7] = { 49 MOV_R7_NR_SIGRETURN, SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN, 50 MOV_R7_NR_RT_SIGRETURN, SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN, 51 }; 52 53 /* 54 * Either we support OABI only, or we have EABI with the OABI 55 * compat layer enabled. In the later case we don't know if 56 * user space is EABI or not, and if not we must not clobber r7. 57 * Always using the OABI syscall solves that issue and works for 58 * all those cases. 59 */ 60 const unsigned long syscall_restart_code[2] = { 61 SWI_SYS_RESTART, /* swi __NR_restart_syscall */ 62 0xe49df004, /* ldr pc, [sp], #4 */ 63 }; 64 65 /* 66 * atomically swap in the new signal mask, and wait for a signal. 67 */ 68 asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask) 69 { 70 mask &= _BLOCKABLE; 71 spin_lock_irq(¤t->sighand->siglock); 72 current->saved_sigmask = current->blocked; 73 siginitset(¤t->blocked, mask); 74 recalc_sigpending(); 75 spin_unlock_irq(¤t->sighand->siglock); 76 77 current->state = TASK_INTERRUPTIBLE; 78 schedule(); 79 set_restore_sigmask(); 80 return -ERESTARTNOHAND; 81 } 82 83 asmlinkage int 84 sys_sigaction(int sig, const struct old_sigaction __user *act, 85 struct old_sigaction __user *oact) 86 { 87 struct k_sigaction new_ka, old_ka; 88 int ret; 89 90 if (act) { 91 old_sigset_t mask; 92 if (!access_ok(VERIFY_READ, act, sizeof(*act)) || 93 __get_user(new_ka.sa.sa_handler, &act->sa_handler) || 94 __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) 95 return -EFAULT; 96 __get_user(new_ka.sa.sa_flags, &act->sa_flags); 97 __get_user(mask, &act->sa_mask); 98 siginitset(&new_ka.sa.sa_mask, mask); 99 } 100 101 ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); 102 103 if (!ret && oact) { 104 if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) || 105 __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || 106 __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) 107 return -EFAULT; 108 __put_user(old_ka.sa.sa_flags, &oact->sa_flags); 109 __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); 110 } 111 112 return ret; 113 } 114 115 #ifdef CONFIG_CRUNCH 116 static int preserve_crunch_context(struct crunch_sigframe __user *frame) 117 { 118 char kbuf[sizeof(*frame) + 8]; 119 struct crunch_sigframe *kframe; 120 121 /* the crunch context must be 64 bit aligned */ 122 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 123 kframe->magic = CRUNCH_MAGIC; 124 kframe->size = CRUNCH_STORAGE_SIZE; 125 crunch_task_copy(current_thread_info(), &kframe->storage); 126 return __copy_to_user(frame, kframe, sizeof(*frame)); 127 } 128 129 static int restore_crunch_context(struct crunch_sigframe __user *frame) 130 { 131 char kbuf[sizeof(*frame) + 8]; 132 struct crunch_sigframe *kframe; 133 134 /* the crunch context must be 64 bit aligned */ 135 kframe = (struct crunch_sigframe *)((unsigned long)(kbuf + 8) & ~7); 136 if (__copy_from_user(kframe, frame, sizeof(*frame))) 137 return -1; 138 if (kframe->magic != CRUNCH_MAGIC || 139 kframe->size != CRUNCH_STORAGE_SIZE) 140 return -1; 141 crunch_task_restore(current_thread_info(), &kframe->storage); 142 return 0; 143 } 144 #endif 145 146 #ifdef CONFIG_IWMMXT 147 148 static int preserve_iwmmxt_context(struct iwmmxt_sigframe *frame) 149 { 150 char kbuf[sizeof(*frame) + 8]; 151 struct iwmmxt_sigframe *kframe; 152 153 /* the iWMMXt context must be 64 bit aligned */ 154 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 155 kframe->magic = IWMMXT_MAGIC; 156 kframe->size = IWMMXT_STORAGE_SIZE; 157 iwmmxt_task_copy(current_thread_info(), &kframe->storage); 158 return __copy_to_user(frame, kframe, sizeof(*frame)); 159 } 160 161 static int restore_iwmmxt_context(struct iwmmxt_sigframe *frame) 162 { 163 char kbuf[sizeof(*frame) + 8]; 164 struct iwmmxt_sigframe *kframe; 165 166 /* the iWMMXt context must be 64 bit aligned */ 167 kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7); 168 if (__copy_from_user(kframe, frame, sizeof(*frame))) 169 return -1; 170 if (kframe->magic != IWMMXT_MAGIC || 171 kframe->size != IWMMXT_STORAGE_SIZE) 172 return -1; 173 iwmmxt_task_restore(current_thread_info(), &kframe->storage); 174 return 0; 175 } 176 177 #endif 178 179 #ifdef CONFIG_VFP 180 181 static int preserve_vfp_context(struct vfp_sigframe __user *frame) 182 { 183 struct thread_info *thread = current_thread_info(); 184 struct vfp_hard_struct *h = &thread->vfpstate.hard; 185 const unsigned long magic = VFP_MAGIC; 186 const unsigned long size = VFP_STORAGE_SIZE; 187 int err = 0; 188 189 vfp_sync_hwstate(thread); 190 __put_user_error(magic, &frame->magic, err); 191 __put_user_error(size, &frame->size, err); 192 193 /* 194 * Copy the floating point registers. There can be unused 195 * registers see asm/hwcap.h for details. 196 */ 197 err |= __copy_to_user(&frame->ufp.fpregs, &h->fpregs, 198 sizeof(h->fpregs)); 199 /* 200 * Copy the status and control register. 201 */ 202 __put_user_error(h->fpscr, &frame->ufp.fpscr, err); 203 204 /* 205 * Copy the exception registers. 206 */ 207 __put_user_error(h->fpexc, &frame->ufp_exc.fpexc, err); 208 __put_user_error(h->fpinst, &frame->ufp_exc.fpinst, err); 209 __put_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err); 210 211 return err ? -EFAULT : 0; 212 } 213 214 static int restore_vfp_context(struct vfp_sigframe __user *frame) 215 { 216 struct thread_info *thread = current_thread_info(); 217 struct vfp_hard_struct *h = &thread->vfpstate.hard; 218 unsigned long magic; 219 unsigned long size; 220 unsigned long fpexc; 221 int err = 0; 222 223 __get_user_error(magic, &frame->magic, err); 224 __get_user_error(size, &frame->size, err); 225 226 if (err) 227 return -EFAULT; 228 if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) 229 return -EINVAL; 230 231 /* 232 * Copy the floating point registers. There can be unused 233 * registers see asm/hwcap.h for details. 234 */ 235 err |= __copy_from_user(&h->fpregs, &frame->ufp.fpregs, 236 sizeof(h->fpregs)); 237 /* 238 * Copy the status and control register. 239 */ 240 __get_user_error(h->fpscr, &frame->ufp.fpscr, err); 241 242 /* 243 * Sanitise and restore the exception registers. 244 */ 245 __get_user_error(fpexc, &frame->ufp_exc.fpexc, err); 246 /* Ensure the VFP is enabled. */ 247 fpexc |= FPEXC_EN; 248 /* Ensure FPINST2 is invalid and the exception flag is cleared. */ 249 fpexc &= ~(FPEXC_EX | FPEXC_FP2V); 250 h->fpexc = fpexc; 251 252 __get_user_error(h->fpinst, &frame->ufp_exc.fpinst, err); 253 __get_user_error(h->fpinst2, &frame->ufp_exc.fpinst2, err); 254 255 if (!err) 256 vfp_flush_hwstate(thread); 257 258 return err ? -EFAULT : 0; 259 } 260 261 #endif 262 263 /* 264 * Do a signal return; undo the signal stack. These are aligned to 64-bit. 265 */ 266 struct sigframe { 267 struct ucontext uc; 268 unsigned long retcode[2]; 269 }; 270 271 struct rt_sigframe { 272 struct siginfo info; 273 struct sigframe sig; 274 }; 275 276 static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf) 277 { 278 struct aux_sigframe __user *aux; 279 sigset_t set; 280 int err; 281 282 err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set)); 283 if (err == 0) { 284 sigdelsetmask(&set, ~_BLOCKABLE); 285 spin_lock_irq(¤t->sighand->siglock); 286 current->blocked = set; 287 recalc_sigpending(); 288 spin_unlock_irq(¤t->sighand->siglock); 289 } 290 291 __get_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 292 __get_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 293 __get_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 294 __get_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 295 __get_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 296 __get_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 297 __get_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 298 __get_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 299 __get_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 300 __get_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 301 __get_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 302 __get_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 303 __get_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 304 __get_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 305 __get_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 306 __get_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 307 __get_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 308 309 err |= !valid_user_regs(regs); 310 311 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 312 #ifdef CONFIG_CRUNCH 313 if (err == 0) 314 err |= restore_crunch_context(&aux->crunch); 315 #endif 316 #ifdef CONFIG_IWMMXT 317 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 318 err |= restore_iwmmxt_context(&aux->iwmmxt); 319 #endif 320 #ifdef CONFIG_VFP 321 if (err == 0) 322 err |= restore_vfp_context(&aux->vfp); 323 #endif 324 325 return err; 326 } 327 328 asmlinkage int sys_sigreturn(struct pt_regs *regs) 329 { 330 struct sigframe __user *frame; 331 332 /* Always make any pending restarted system calls return -EINTR */ 333 current_thread_info()->restart_block.fn = do_no_restart_syscall; 334 335 /* 336 * Since we stacked the signal on a 64-bit boundary, 337 * then 'sp' should be word aligned here. If it's 338 * not, then the user is trying to mess with us. 339 */ 340 if (regs->ARM_sp & 7) 341 goto badframe; 342 343 frame = (struct sigframe __user *)regs->ARM_sp; 344 345 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 346 goto badframe; 347 348 if (restore_sigframe(regs, frame)) 349 goto badframe; 350 351 single_step_trap(current); 352 353 return regs->ARM_r0; 354 355 badframe: 356 force_sig(SIGSEGV, current); 357 return 0; 358 } 359 360 asmlinkage int sys_rt_sigreturn(struct pt_regs *regs) 361 { 362 struct rt_sigframe __user *frame; 363 364 /* Always make any pending restarted system calls return -EINTR */ 365 current_thread_info()->restart_block.fn = do_no_restart_syscall; 366 367 /* 368 * Since we stacked the signal on a 64-bit boundary, 369 * then 'sp' should be word aligned here. If it's 370 * not, then the user is trying to mess with us. 371 */ 372 if (regs->ARM_sp & 7) 373 goto badframe; 374 375 frame = (struct rt_sigframe __user *)regs->ARM_sp; 376 377 if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) 378 goto badframe; 379 380 if (restore_sigframe(regs, &frame->sig)) 381 goto badframe; 382 383 if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->ARM_sp) == -EFAULT) 384 goto badframe; 385 386 single_step_trap(current); 387 388 return regs->ARM_r0; 389 390 badframe: 391 force_sig(SIGSEGV, current); 392 return 0; 393 } 394 395 static int 396 setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set) 397 { 398 struct aux_sigframe __user *aux; 399 int err = 0; 400 401 __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err); 402 __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err); 403 __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err); 404 __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err); 405 __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err); 406 __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err); 407 __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err); 408 __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err); 409 __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err); 410 __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err); 411 __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err); 412 __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err); 413 __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err); 414 __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err); 415 __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err); 416 __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err); 417 __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err); 418 419 __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err); 420 __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err); 421 __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err); 422 __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); 423 424 err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set)); 425 426 aux = (struct aux_sigframe __user *) sf->uc.uc_regspace; 427 #ifdef CONFIG_CRUNCH 428 if (err == 0) 429 err |= preserve_crunch_context(&aux->crunch); 430 #endif 431 #ifdef CONFIG_IWMMXT 432 if (err == 0 && test_thread_flag(TIF_USING_IWMMXT)) 433 err |= preserve_iwmmxt_context(&aux->iwmmxt); 434 #endif 435 #ifdef CONFIG_VFP 436 if (err == 0) 437 err |= preserve_vfp_context(&aux->vfp); 438 #endif 439 __put_user_error(0, &aux->end_magic, err); 440 441 return err; 442 } 443 444 static inline void __user * 445 get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize) 446 { 447 unsigned long sp = regs->ARM_sp; 448 void __user *frame; 449 450 /* 451 * This is the X/Open sanctioned signal stack switching. 452 */ 453 if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp)) 454 sp = current->sas_ss_sp + current->sas_ss_size; 455 456 /* 457 * ATPCS B01 mandates 8-byte alignment 458 */ 459 frame = (void __user *)((sp - framesize) & ~7); 460 461 /* 462 * Check that we can actually write to the signal frame. 463 */ 464 if (!access_ok(VERIFY_WRITE, frame, framesize)) 465 frame = NULL; 466 467 return frame; 468 } 469 470 static int 471 setup_return(struct pt_regs *regs, struct k_sigaction *ka, 472 unsigned long __user *rc, void __user *frame, int usig) 473 { 474 unsigned long handler = (unsigned long)ka->sa.sa_handler; 475 unsigned long retcode; 476 int thumb = 0; 477 unsigned long cpsr = regs->ARM_cpsr & ~PSR_f; 478 479 /* 480 * Maybe we need to deliver a 32-bit signal to a 26-bit task. 481 */ 482 if (ka->sa.sa_flags & SA_THIRTYTWO) 483 cpsr = (cpsr & ~MODE_MASK) | USR_MODE; 484 485 #ifdef CONFIG_ARM_THUMB 486 if (elf_hwcap & HWCAP_THUMB) { 487 /* 488 * The LSB of the handler determines if we're going to 489 * be using THUMB or ARM mode for this signal handler. 490 */ 491 thumb = handler & 1; 492 493 if (thumb) { 494 cpsr |= PSR_T_BIT; 495 #if __LINUX_ARM_ARCH__ >= 7 496 /* clear the If-Then Thumb-2 execution state */ 497 cpsr &= ~PSR_IT_MASK; 498 #endif 499 } else 500 cpsr &= ~PSR_T_BIT; 501 } 502 #endif 503 504 if (ka->sa.sa_flags & SA_RESTORER) { 505 retcode = (unsigned long)ka->sa.sa_restorer; 506 } else { 507 unsigned int idx = thumb << 1; 508 509 if (ka->sa.sa_flags & SA_SIGINFO) 510 idx += 3; 511 512 if (__put_user(sigreturn_codes[idx], rc) || 513 __put_user(sigreturn_codes[idx+1], rc+1)) 514 return 1; 515 516 if (cpsr & MODE32_BIT) { 517 /* 518 * 32-bit code can use the new high-page 519 * signal return code support. 520 */ 521 retcode = KERN_SIGRETURN_CODE + (idx << 2) + thumb; 522 } else { 523 /* 524 * Ensure that the instruction cache sees 525 * the return code written onto the stack. 526 */ 527 flush_icache_range((unsigned long)rc, 528 (unsigned long)(rc + 2)); 529 530 retcode = ((unsigned long)rc) + thumb; 531 } 532 } 533 534 regs->ARM_r0 = usig; 535 regs->ARM_sp = (unsigned long)frame; 536 regs->ARM_lr = retcode; 537 regs->ARM_pc = handler; 538 regs->ARM_cpsr = cpsr; 539 540 return 0; 541 } 542 543 static int 544 setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) 545 { 546 struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 547 int err = 0; 548 549 if (!frame) 550 return 1; 551 552 /* 553 * Set uc.uc_flags to a value which sc.trap_no would never have. 554 */ 555 __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); 556 557 err |= setup_sigframe(frame, regs, set); 558 if (err == 0) 559 err = setup_return(regs, ka, frame->retcode, frame, usig); 560 561 return err; 562 } 563 564 static int 565 setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info, 566 sigset_t *set, struct pt_regs *regs) 567 { 568 struct rt_sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame)); 569 stack_t stack; 570 int err = 0; 571 572 if (!frame) 573 return 1; 574 575 err |= copy_siginfo_to_user(&frame->info, info); 576 577 __put_user_error(0, &frame->sig.uc.uc_flags, err); 578 __put_user_error(NULL, &frame->sig.uc.uc_link, err); 579 580 memset(&stack, 0, sizeof(stack)); 581 stack.ss_sp = (void __user *)current->sas_ss_sp; 582 stack.ss_flags = sas_ss_flags(regs->ARM_sp); 583 stack.ss_size = current->sas_ss_size; 584 err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack)); 585 586 err |= setup_sigframe(&frame->sig, regs, set); 587 if (err == 0) 588 err = setup_return(regs, ka, frame->sig.retcode, frame, usig); 589 590 if (err == 0) { 591 /* 592 * For realtime signals we must also set the second and third 593 * arguments for the signal handler. 594 * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06 595 */ 596 regs->ARM_r1 = (unsigned long)&frame->info; 597 regs->ARM_r2 = (unsigned long)&frame->sig.uc; 598 } 599 600 return err; 601 } 602 603 static inline void setup_syscall_restart(struct pt_regs *regs) 604 { 605 regs->ARM_r0 = regs->ARM_ORIG_r0; 606 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4; 607 } 608 609 /* 610 * OK, we're invoking a handler 611 */ 612 static int 613 handle_signal(unsigned long sig, struct k_sigaction *ka, 614 siginfo_t *info, sigset_t *oldset, 615 struct pt_regs * regs, int syscall) 616 { 617 struct thread_info *thread = current_thread_info(); 618 struct task_struct *tsk = current; 619 int usig = sig; 620 int ret; 621 622 /* 623 * If we were from a system call, check for system call restarting... 624 */ 625 if (syscall) { 626 switch (regs->ARM_r0) { 627 case -ERESTART_RESTARTBLOCK: 628 case -ERESTARTNOHAND: 629 regs->ARM_r0 = -EINTR; 630 break; 631 case -ERESTARTSYS: 632 if (!(ka->sa.sa_flags & SA_RESTART)) { 633 regs->ARM_r0 = -EINTR; 634 break; 635 } 636 /* fallthrough */ 637 case -ERESTARTNOINTR: 638 setup_syscall_restart(regs); 639 } 640 } 641 642 /* 643 * translate the signal 644 */ 645 if (usig < 32 && thread->exec_domain && thread->exec_domain->signal_invmap) 646 usig = thread->exec_domain->signal_invmap[usig]; 647 648 /* 649 * Set up the stack frame 650 */ 651 if (ka->sa.sa_flags & SA_SIGINFO) 652 ret = setup_rt_frame(usig, ka, info, oldset, regs); 653 else 654 ret = setup_frame(usig, ka, oldset, regs); 655 656 /* 657 * Check that the resulting registers are actually sane. 658 */ 659 ret |= !valid_user_regs(regs); 660 661 if (ret != 0) { 662 force_sigsegv(sig, tsk); 663 return ret; 664 } 665 666 /* 667 * Block the signal if we were successful. 668 */ 669 spin_lock_irq(&tsk->sighand->siglock); 670 sigorsets(&tsk->blocked, &tsk->blocked, 671 &ka->sa.sa_mask); 672 if (!(ka->sa.sa_flags & SA_NODEFER)) 673 sigaddset(&tsk->blocked, sig); 674 recalc_sigpending(); 675 spin_unlock_irq(&tsk->sighand->siglock); 676 677 return 0; 678 } 679 680 /* 681 * Note that 'init' is a special process: it doesn't get signals it doesn't 682 * want to handle. Thus you cannot kill init even with a SIGKILL even by 683 * mistake. 684 * 685 * Note that we go through the signals twice: once to check the signals that 686 * the kernel can handle, and then we build all the user-level signal handling 687 * stack-frames in one go after that. 688 */ 689 static void do_signal(struct pt_regs *regs, int syscall) 690 { 691 struct k_sigaction ka; 692 siginfo_t info; 693 int signr; 694 695 /* 696 * We want the common case to go fast, which 697 * is why we may in certain cases get here from 698 * kernel mode. Just return without doing anything 699 * if so. 700 */ 701 if (!user_mode(regs)) 702 return; 703 704 if (try_to_freeze()) 705 goto no_signal; 706 707 single_step_clear(current); 708 709 signr = get_signal_to_deliver(&info, &ka, regs, NULL); 710 if (signr > 0) { 711 sigset_t *oldset; 712 713 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 714 oldset = ¤t->saved_sigmask; 715 else 716 oldset = ¤t->blocked; 717 if (handle_signal(signr, &ka, &info, oldset, regs, syscall) == 0) { 718 /* 719 * A signal was successfully delivered; the saved 720 * sigmask will have been stored in the signal frame, 721 * and will be restored by sigreturn, so we can simply 722 * clear the TIF_RESTORE_SIGMASK flag. 723 */ 724 if (test_thread_flag(TIF_RESTORE_SIGMASK)) 725 clear_thread_flag(TIF_RESTORE_SIGMASK); 726 } 727 single_step_set(current); 728 return; 729 } 730 731 no_signal: 732 /* 733 * No signal to deliver to the process - restart the syscall. 734 */ 735 if (syscall) { 736 if (regs->ARM_r0 == -ERESTART_RESTARTBLOCK) { 737 if (thumb_mode(regs)) { 738 regs->ARM_r7 = __NR_restart_syscall - __NR_SYSCALL_BASE; 739 regs->ARM_pc -= 2; 740 } else { 741 #if defined(CONFIG_AEABI) && !defined(CONFIG_OABI_COMPAT) 742 regs->ARM_r7 = __NR_restart_syscall; 743 regs->ARM_pc -= 4; 744 #else 745 u32 __user *usp; 746 747 regs->ARM_sp -= 4; 748 usp = (u32 __user *)regs->ARM_sp; 749 750 if (put_user(regs->ARM_pc, usp) == 0) { 751 regs->ARM_pc = KERN_RESTART_CODE; 752 } else { 753 regs->ARM_sp += 4; 754 force_sigsegv(0, current); 755 } 756 #endif 757 } 758 } 759 if (regs->ARM_r0 == -ERESTARTNOHAND || 760 regs->ARM_r0 == -ERESTARTSYS || 761 regs->ARM_r0 == -ERESTARTNOINTR) { 762 setup_syscall_restart(regs); 763 } 764 765 /* If there's no signal to deliver, we just put the saved sigmask 766 * back. 767 */ 768 if (test_thread_flag(TIF_RESTORE_SIGMASK)) { 769 clear_thread_flag(TIF_RESTORE_SIGMASK); 770 sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); 771 } 772 } 773 single_step_set(current); 774 } 775 776 asmlinkage void 777 do_notify_resume(struct pt_regs *regs, unsigned int thread_flags, int syscall) 778 { 779 if (thread_flags & _TIF_SIGPENDING) 780 do_signal(regs, syscall); 781 782 if (thread_flags & _TIF_NOTIFY_RESUME) { 783 clear_thread_flag(TIF_NOTIFY_RESUME); 784 tracehook_notify_resume(regs); 785 if (current->replacement_session_keyring) 786 key_replace_session_keyring(); 787 } 788 } 789