1 /* 2 * linux/arch/sh/kernel/signal.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 * 6 * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson 7 * 8 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima 9 * 10 */ 11 #include <linux/sched.h> 12 #include <linux/mm.h> 13 #include <linux/smp.h> 14 #include <linux/kernel.h> 15 #include <linux/signal.h> 16 #include <linux/errno.h> 17 #include <linux/wait.h> 18 #include <linux/ptrace.h> 19 #include <linux/unistd.h> 20 #include <linux/stddef.h> 21 #include <linux/tty.h> 22 #include <linux/elf.h> 23 #include <linux/personality.h> 24 #include <linux/binfmts.h> 25 #include <linux/io.h> 26 #include <linux/tracehook.h> 27 #include <asm/ucontext.h> 28 #include <asm/uaccess.h> 29 #include <asm/pgtable.h> 30 #include <asm/cacheflush.h> 31 #include <asm/syscalls.h> 32 #include <asm/fpu.h> 33 34 struct fdpic_func_descriptor { 35 unsigned long text; 36 unsigned long GOT; 37 }; 38 39 /* 40 * The following define adds a 64 byte gap between the signal 41 * stack frame and previous contents of the stack. This allows 42 * frame unwinding in a function epilogue but only if a frame 43 * pointer is used in the function. This is necessary because 44 * current gcc compilers (<4.3) do not generate unwind info on 45 * SH for function epilogues. 46 */ 47 #define UNWINDGUARD 64 48 49 /* 50 * Do a signal return; undo the signal stack. 51 */ 52 53 #define MOVW(n) (0x9300|((n)-2)) /* Move mem word at PC+n to R3 */ 54 #if defined(CONFIG_CPU_SH2) 55 #define TRAP_NOARG 0xc320 /* Syscall w/no args (NR in R3) */ 56 #else 57 #define TRAP_NOARG 0xc310 /* Syscall w/no args (NR in R3) */ 58 #endif 59 #define OR_R0_R0 0x200b /* or r0,r0 (insert to avoid hardware bug) */ 60 61 struct sigframe 62 { 63 struct sigcontext sc; 64 unsigned long extramask[_NSIG_WORDS-1]; 65 u16 retcode[8]; 66 }; 67 68 struct rt_sigframe 69 { 70 struct siginfo info; 71 struct ucontext uc; 72 u16 retcode[8]; 73 }; 74 75 #ifdef CONFIG_SH_FPU 76 static inline int restore_sigcontext_fpu(struct sigcontext __user *sc) 77 { 78 struct task_struct *tsk = current; 79 80 if (!(boot_cpu_data.flags & CPU_HAS_FPU)) 81 return 0; 82 83 set_used_math(); 84 return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0], 85 sizeof(long)*(16*2+2)); 86 } 87 88 static inline int save_sigcontext_fpu(struct sigcontext __user *sc, 89 struct pt_regs *regs) 90 { 91 struct task_struct *tsk = current; 92 93 if (!(boot_cpu_data.flags & CPU_HAS_FPU)) 94 return 0; 95 96 if (!used_math()) 97 return __put_user(0, &sc->sc_ownedfp); 98 99 if (__put_user(1, &sc->sc_ownedfp)) 100 return -EFAULT; 101 102 /* This will cause a "finit" to be triggered by the next 103 attempted FPU operation by the 'current' process. 104 */ 105 clear_used_math(); 106 107 unlazy_fpu(tsk, regs); 108 return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu, 109 sizeof(long)*(16*2+2)); 110 } 111 #endif /* CONFIG_SH_FPU */ 112 113 static int 114 restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p) 115 { 116 unsigned int err = 0; 117 118 #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x) 119 COPY(regs[1]); 120 COPY(regs[2]); COPY(regs[3]); 121 COPY(regs[4]); COPY(regs[5]); 122 COPY(regs[6]); COPY(regs[7]); 123 COPY(regs[8]); COPY(regs[9]); 124 COPY(regs[10]); COPY(regs[11]); 125 COPY(regs[12]); COPY(regs[13]); 126 COPY(regs[14]); COPY(regs[15]); 127 COPY(gbr); COPY(mach); 128 COPY(macl); COPY(pr); 129 COPY(sr); COPY(pc); 130 #undef COPY 131 132 #ifdef CONFIG_SH_FPU 133 if (boot_cpu_data.flags & CPU_HAS_FPU) { 134 int owned_fp; 135 struct task_struct *tsk = current; 136 137 regs->sr |= SR_FD; /* Release FPU */ 138 clear_fpu(tsk, regs); 139 clear_used_math(); 140 err |= __get_user (owned_fp, &sc->sc_ownedfp); 141 if (owned_fp) 142 err |= restore_sigcontext_fpu(sc); 143 } 144 #endif 145 146 regs->tra = -1; /* disable syscall checks */ 147 err |= __get_user(*r0_p, &sc->sc_regs[0]); 148 return err; 149 } 150 151 asmlinkage int sys_sigreturn(void) 152 { 153 struct pt_regs *regs = current_pt_regs(); 154 struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15]; 155 sigset_t set; 156 int r0; 157 158 /* Always make any pending restarted system calls return -EINTR */ 159 current->restart_block.fn = do_no_restart_syscall; 160 161 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 162 goto badframe; 163 164 if (__get_user(set.sig[0], &frame->sc.oldmask) 165 || (_NSIG_WORDS > 1 166 && __copy_from_user(&set.sig[1], &frame->extramask, 167 sizeof(frame->extramask)))) 168 goto badframe; 169 170 set_current_blocked(&set); 171 172 if (restore_sigcontext(regs, &frame->sc, &r0)) 173 goto badframe; 174 return r0; 175 176 badframe: 177 force_sig(SIGSEGV, current); 178 return 0; 179 } 180 181 asmlinkage int sys_rt_sigreturn(void) 182 { 183 struct pt_regs *regs = current_pt_regs(); 184 struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15]; 185 sigset_t set; 186 int r0; 187 188 /* Always make any pending restarted system calls return -EINTR */ 189 current->restart_block.fn = do_no_restart_syscall; 190 191 if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) 192 goto badframe; 193 194 if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) 195 goto badframe; 196 197 set_current_blocked(&set); 198 199 if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0)) 200 goto badframe; 201 202 if (restore_altstack(&frame->uc.uc_stack)) 203 goto badframe; 204 205 return r0; 206 207 badframe: 208 force_sig(SIGSEGV, current); 209 return 0; 210 } 211 212 /* 213 * Set up a signal frame. 214 */ 215 216 static int 217 setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, 218 unsigned long mask) 219 { 220 int err = 0; 221 222 #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) 223 COPY(regs[0]); COPY(regs[1]); 224 COPY(regs[2]); COPY(regs[3]); 225 COPY(regs[4]); COPY(regs[5]); 226 COPY(regs[6]); COPY(regs[7]); 227 COPY(regs[8]); COPY(regs[9]); 228 COPY(regs[10]); COPY(regs[11]); 229 COPY(regs[12]); COPY(regs[13]); 230 COPY(regs[14]); COPY(regs[15]); 231 COPY(gbr); COPY(mach); 232 COPY(macl); COPY(pr); 233 COPY(sr); COPY(pc); 234 #undef COPY 235 236 #ifdef CONFIG_SH_FPU 237 err |= save_sigcontext_fpu(sc, regs); 238 #endif 239 240 /* non-iBCS2 extensions.. */ 241 err |= __put_user(mask, &sc->oldmask); 242 243 return err; 244 } 245 246 /* 247 * Determine which stack to use.. 248 */ 249 static inline void __user * 250 get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) 251 { 252 if (ka->sa.sa_flags & SA_ONSTACK) { 253 if (sas_ss_flags(sp) == 0) 254 sp = current->sas_ss_sp + current->sas_ss_size; 255 } 256 257 return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul); 258 } 259 260 /* These symbols are defined with the addresses in the vsyscall page. 261 See vsyscall-trapa.S. */ 262 extern void __kernel_sigreturn(void); 263 extern void __kernel_rt_sigreturn(void); 264 265 static int setup_frame(struct ksignal *ksig, sigset_t *set, 266 struct pt_regs *regs) 267 { 268 struct sigframe __user *frame; 269 int err = 0, sig = ksig->sig; 270 271 frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame)); 272 273 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 274 return -EFAULT; 275 276 err |= setup_sigcontext(&frame->sc, regs, set->sig[0]); 277 278 if (_NSIG_WORDS > 1) 279 err |= __copy_to_user(frame->extramask, &set->sig[1], 280 sizeof(frame->extramask)); 281 282 /* Set up to return from userspace. If provided, use a stub 283 already in userspace. */ 284 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 285 regs->pr = (unsigned long) ksig->ka.sa.sa_restorer; 286 #ifdef CONFIG_VSYSCALL 287 } else if (likely(current->mm->context.vdso)) { 288 regs->pr = VDSO_SYM(&__kernel_sigreturn); 289 #endif 290 } else { 291 /* Generate return code (system call to sigreturn) */ 292 err |= __put_user(MOVW(7), &frame->retcode[0]); 293 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 294 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 295 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 296 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 297 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 298 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 299 err |= __put_user((__NR_sigreturn), &frame->retcode[7]); 300 regs->pr = (unsigned long) frame->retcode; 301 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 302 } 303 304 if (err) 305 return -EFAULT; 306 307 /* Set up registers for signal handler */ 308 regs->regs[15] = (unsigned long) frame; 309 regs->regs[4] = sig; /* Arg for signal handler */ 310 regs->regs[5] = 0; 311 regs->regs[6] = (unsigned long) &frame->sc; 312 313 if (current->personality & FDPIC_FUNCPTRS) { 314 struct fdpic_func_descriptor __user *funcptr = 315 (struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler; 316 317 err |= __get_user(regs->pc, &funcptr->text); 318 err |= __get_user(regs->regs[12], &funcptr->GOT); 319 } else 320 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; 321 322 if (err) 323 return -EFAULT; 324 325 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 326 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 327 328 return 0; 329 } 330 331 static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, 332 struct pt_regs *regs) 333 { 334 struct rt_sigframe __user *frame; 335 int err = 0, sig = ksig->sig; 336 337 frame = get_sigframe(&ksig->ka, regs->regs[15], sizeof(*frame)); 338 339 if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) 340 return -EFAULT; 341 342 err |= copy_siginfo_to_user(&frame->info, &ksig->info); 343 344 /* Create the ucontext. */ 345 err |= __put_user(0, &frame->uc.uc_flags); 346 err |= __put_user(NULL, &frame->uc.uc_link); 347 err |= __save_altstack(&frame->uc.uc_stack, regs->regs[15]); 348 err |= setup_sigcontext(&frame->uc.uc_mcontext, 349 regs, set->sig[0]); 350 err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); 351 352 /* Set up to return from userspace. If provided, use a stub 353 already in userspace. */ 354 if (ksig->ka.sa.sa_flags & SA_RESTORER) { 355 regs->pr = (unsigned long) ksig->ka.sa.sa_restorer; 356 #ifdef CONFIG_VSYSCALL 357 } else if (likely(current->mm->context.vdso)) { 358 regs->pr = VDSO_SYM(&__kernel_rt_sigreturn); 359 #endif 360 } else { 361 /* Generate return code (system call to rt_sigreturn) */ 362 err |= __put_user(MOVW(7), &frame->retcode[0]); 363 err |= __put_user(TRAP_NOARG, &frame->retcode[1]); 364 err |= __put_user(OR_R0_R0, &frame->retcode[2]); 365 err |= __put_user(OR_R0_R0, &frame->retcode[3]); 366 err |= __put_user(OR_R0_R0, &frame->retcode[4]); 367 err |= __put_user(OR_R0_R0, &frame->retcode[5]); 368 err |= __put_user(OR_R0_R0, &frame->retcode[6]); 369 err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]); 370 regs->pr = (unsigned long) frame->retcode; 371 flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode)); 372 } 373 374 if (err) 375 return -EFAULT; 376 377 /* Set up registers for signal handler */ 378 regs->regs[15] = (unsigned long) frame; 379 regs->regs[4] = sig; /* Arg for signal handler */ 380 regs->regs[5] = (unsigned long) &frame->info; 381 regs->regs[6] = (unsigned long) &frame->uc; 382 383 if (current->personality & FDPIC_FUNCPTRS) { 384 struct fdpic_func_descriptor __user *funcptr = 385 (struct fdpic_func_descriptor __user *)ksig->ka.sa.sa_handler; 386 387 err |= __get_user(regs->pc, &funcptr->text); 388 err |= __get_user(regs->regs[12], &funcptr->GOT); 389 } else 390 regs->pc = (unsigned long)ksig->ka.sa.sa_handler; 391 392 if (err) 393 return -EFAULT; 394 395 pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx\n", 396 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr); 397 398 return 0; 399 } 400 401 static inline void 402 handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs, 403 struct sigaction *sa) 404 { 405 /* If we're not from a syscall, bail out */ 406 if (regs->tra < 0) 407 return; 408 409 /* check for system call restart.. */ 410 switch (regs->regs[0]) { 411 case -ERESTART_RESTARTBLOCK: 412 case -ERESTARTNOHAND: 413 no_system_call_restart: 414 regs->regs[0] = -EINTR; 415 break; 416 417 case -ERESTARTSYS: 418 if (!(sa->sa_flags & SA_RESTART)) 419 goto no_system_call_restart; 420 /* fallthrough */ 421 case -ERESTARTNOINTR: 422 regs->regs[0] = save_r0; 423 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 424 break; 425 } 426 } 427 428 /* 429 * OK, we're invoking a handler 430 */ 431 static void 432 handle_signal(struct ksignal *ksig, struct pt_regs *regs, unsigned int save_r0) 433 { 434 sigset_t *oldset = sigmask_to_save(); 435 int ret; 436 437 /* Set up the stack frame */ 438 if (ksig->ka.sa.sa_flags & SA_SIGINFO) 439 ret = setup_rt_frame(ksig, oldset, regs); 440 else 441 ret = setup_frame(ksig, oldset, regs); 442 443 signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); 444 } 445 446 /* 447 * Note that 'init' is a special process: it doesn't get signals it doesn't 448 * want to handle. Thus you cannot kill init even with a SIGKILL even by 449 * mistake. 450 * 451 * Note that we go through the signals twice: once to check the signals that 452 * the kernel can handle, and then we build all the user-level signal handling 453 * stack-frames in one go after that. 454 */ 455 static void do_signal(struct pt_regs *regs, unsigned int save_r0) 456 { 457 struct ksignal ksig; 458 459 /* 460 * We want the common case to go fast, which 461 * is why we may in certain cases get here from 462 * kernel mode. Just return without doing anything 463 * if so. 464 */ 465 if (!user_mode(regs)) 466 return; 467 468 if (get_signal(&ksig)) { 469 handle_syscall_restart(save_r0, regs, &ksig.ka.sa); 470 471 /* Whee! Actually deliver the signal. */ 472 handle_signal(&ksig, regs, save_r0); 473 return; 474 } 475 476 /* Did we come from a system call? */ 477 if (regs->tra >= 0) { 478 /* Restart the system call - no handlers present */ 479 if (regs->regs[0] == -ERESTARTNOHAND || 480 regs->regs[0] == -ERESTARTSYS || 481 regs->regs[0] == -ERESTARTNOINTR) { 482 regs->regs[0] = save_r0; 483 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 484 } else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) { 485 regs->pc -= instruction_size(__raw_readw(regs->pc - 4)); 486 regs->regs[3] = __NR_restart_syscall; 487 } 488 } 489 490 /* 491 * If there's no signal to deliver, we just put the saved sigmask 492 * back. 493 */ 494 restore_saved_sigmask(); 495 } 496 497 asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0, 498 unsigned long thread_info_flags) 499 { 500 /* deal with pending signal delivery */ 501 if (thread_info_flags & _TIF_SIGPENDING) 502 do_signal(regs, save_r0); 503 504 if (thread_info_flags & _TIF_NOTIFY_RESUME) { 505 clear_thread_flag(TIF_NOTIFY_RESUME); 506 tracehook_notify_resume(regs); 507 } 508 } 509