/* * BK Id: SCCS/s.signal.c 1.10 11/23/01 16:38:30 paulus */ /* * linux/arch/ppc/kernel/signal.c * * PowerPC version * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) * * Derived from "arch/i386/kernel/signal.c" * Copyright (C) 1991, 1992 Linus Torvalds * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DEBUG_SIG 0 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) #ifndef MIN #define MIN(a,b) (((a) < (b)) ? (a) : (b)) #endif #define GP_REGS_SIZE MIN(sizeof(elf_gregset_t), sizeof(struct pt_regs)) /* * These are the flags in the MSR that the user is allowed to change * by modifying the saved value of the MSR on the stack. SE and BE * should not be in this list since gdb may want to change these. I.e, * you should be able to step out of a signal handler to see what * instruction executes next after the signal handler completes. * Alternately, if you stepped into a signal handler, you should be * able to continue 'til the next breakpoint from within the signal * handler, even if the handler returns. */ #define MSR_USERCHANGE (MSR_FE0 | MSR_FE1) int do_signal(sigset_t *oldset, struct pt_regs *regs); int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from) { if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) return -EFAULT; if (from->si_code < 0) return __copy_to_user(to, from, sizeof(siginfo_t)); else { int err; /* If you change siginfo_t structure, please be sure this code is fixed accordingly. It should never copy any pad contained in the structure to avoid security leaks, but must copy the generic 3 ints plus the relevant union member. */ err = __put_user(from->si_signo, &to->si_signo); err |= __put_user(from->si_errno, &to->si_errno); err |= __put_user((short)from->si_code, &to->si_code); /* First 32bits of unions are always present. */ err |= __put_user(from->si_pid, &to->si_pid); switch (from->si_code >> 16) { case __SI_FAULT >> 16: break; case __SI_CHLD >> 16: err |= __put_user(from->si_utime, &to->si_utime); err |= __put_user(from->si_stime, &to->si_stime); err |= __put_user(from->si_status, &to->si_status); default: err |= __put_user(from->si_uid, &to->si_uid); break; /* case __SI_RT: This is not generated by the kernel as of now. */ } return err; } } /* * Atomically swap in the new signal mask, and wait for a signal. */ int sys_sigsuspend(old_sigset_t mask, int p2, int p3, int p4, int p6, int p7, struct pt_regs *regs) { sigset_t saveset; mask &= _BLOCKABLE; spin_lock_irq(¤t->sigmask_lock); saveset = current->blocked; siginitset(¤t->blocked, mask); recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); regs->gpr[3] = -EINTR; while (1) { current->state = TASK_INTERRUPTIBLE; schedule(); if (do_signal(&saveset, regs)) /* * If a signal handler needs to be called, * do_signal() has set R3 to the signal number (the * first argument of the signal handler), so don't * overwrite that with EINTR ! * In the other cases, do_signal() doesn't touch * R3, so it's still set to -EINTR (see above). */ return regs->gpr[3]; } } int sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, int p3, int p4, int p6, int p7, struct pt_regs *regs) { sigset_t saveset, newset; /* XXX: Don't preclude handling different sized sigset_t's. */ if (sigsetsize != sizeof(sigset_t)) return -EINVAL; if (copy_from_user(&newset, unewset, sizeof(newset))) return -EFAULT; sigdelsetmask(&newset, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); saveset = current->blocked; current->blocked = newset; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); regs->gpr[3] = -EINTR; while (1) { current->state = TASK_INTERRUPTIBLE; schedule(); if (do_signal(&saveset, regs)) return regs->gpr[3]; } } int sys_sigaltstack(const stack_t *uss, stack_t *uoss) { struct pt_regs *regs = (struct pt_regs *) &uss; return do_sigaltstack(uss, uoss, regs->gpr[1]); } int sys_sigaction(int sig, const struct old_sigaction *act, struct old_sigaction *oact) { struct k_sigaction new_ka, old_ka; int ret; if (act) { old_sigset_t mask; if (verify_area(VERIFY_READ, act, sizeof(*act)) || __get_user(new_ka.sa.sa_handler, &act->sa_handler) || __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) return -EFAULT; __get_user(new_ka.sa.sa_flags, &act->sa_flags); __get_user(mask, &act->sa_mask); siginitset(&new_ka.sa.sa_mask, mask); } ret = do_sigaction(sig, (act? &new_ka: NULL), (oact? &old_ka: NULL)); if (!ret && oact) { if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) || __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) return -EFAULT; __put_user(old_ka.sa.sa_flags, &oact->sa_flags); __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); } return ret; } /* * When we have signals to deliver, we set up on the * user stack, going down from the original stack pointer: * a sigregs struct * one or more sigcontext structs with * a gap of __SIGNAL_FRAMESIZE bytes * * Each of these things must be a multiple of 16 bytes in size. * */ struct sigregs { elf_gregset_t gp_regs; double fp_regs[ELF_NFPREG]; unsigned long tramp[2]; /* Programs using the rs6000/xcoff abi can save up to 19 gp regs and 18 fp regs below sp before decrementing it. */ int abigap[56]; }; struct rt_sigframe { unsigned long _unused[2]; struct siginfo *pinfo; void *puc; struct siginfo info; struct ucontext uc; }; /* * When we have rt signals to deliver, we set up on the * user stack, going down from the original stack pointer: * a sigregs struct * one rt_sigframe struct (siginfo + ucontext) * a gap of __SIGNAL_FRAMESIZE bytes * * Each of these things must be a multiple of 16 bytes in size. * */ int sys_rt_sigreturn(struct pt_regs *regs) { struct rt_sigframe *rt_sf; struct sigcontext_struct sigctx; struct sigregs *sr; int ret; elf_gregset_t saved_regs; /* an array of ELF_NGREG unsigned longs */ sigset_t set; stack_t st; unsigned long prevsp; rt_sf = (struct rt_sigframe *)(regs->gpr[1] + __SIGNAL_FRAMESIZE); if (copy_from_user(&sigctx, &rt_sf->uc.uc_mcontext, sizeof(sigctx)) || copy_from_user(&set, &rt_sf->uc.uc_sigmask, sizeof(set)) || copy_from_user(&st, &rt_sf->uc.uc_stack, sizeof(st))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); current->blocked = set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); if (regs->msr & MSR_FP) giveup_fpu(current); rt_sf++; /* Look at next rt_sigframe */ if (rt_sf == (struct rt_sigframe *)(sigctx.regs)) { /* Last stacked signal - restore registers - * sigctx is initialized to point to the * preamble frame (where registers are stored) * see handle_signal() */ sr = (struct sigregs *) sigctx.regs; if (copy_from_user(saved_regs, &sr->gp_regs, sizeof(sr->gp_regs))) goto badframe; saved_regs[PT_MSR] = (regs->msr & ~MSR_USERCHANGE) | (saved_regs[PT_MSR] & MSR_USERCHANGE); memcpy(regs, saved_regs, GP_REGS_SIZE); if (copy_from_user(current->thread.fpr, &sr->fp_regs, sizeof(sr->fp_regs))) goto badframe; /* This function sets back the stack flags into the current task structure. */ sys_sigaltstack(&st, NULL); ret = regs->result; } else { /* More signals to go */ /* Set up registers for next signal handler */ regs->gpr[1] = (unsigned long)rt_sf - __SIGNAL_FRAMESIZE; if (copy_from_user(&sigctx, &rt_sf->uc.uc_mcontext, sizeof(sigctx))) goto badframe; sr = (struct sigregs *) sigctx.regs; regs->gpr[3] = ret = sigctx.signal; /* Get the siginfo */ get_user(regs->gpr[4], (unsigned long *)&rt_sf->pinfo); /* Get the ucontext */ get_user(regs->gpr[5], (unsigned long *)&rt_sf->puc); regs->gpr[6] = (unsigned long) rt_sf; regs->link = (unsigned long) &sr->tramp; regs->nip = sigctx.handler; if (get_user(prevsp, &sr->gp_regs[PT_R1]) || put_user(prevsp, (unsigned long *) regs->gpr[1])) goto badframe; current->thread.fpscr = 0; } return ret; badframe: do_exit(SIGSEGV); } static void setup_rt_frame(struct pt_regs *regs, struct sigregs *frame, signed long newsp) { struct rt_sigframe *rt_sf = (struct rt_sigframe *) newsp; /* Set up preamble frame */ if (verify_area(VERIFY_WRITE, frame, sizeof(*frame))) goto badframe; if (regs->msr & MSR_FP) giveup_fpu(current); if (__copy_to_user(&frame->gp_regs, regs, GP_REGS_SIZE) || __copy_to_user(&frame->fp_regs, current->thread.fpr, ELF_NFPREG * sizeof(double)) /* Set up to return from user space. It calls the sc exception at offset 0x9999 for sys_rt_sigreturn(). */ || __put_user(0x38006666UL, &frame->tramp[0]) /* li r0,0x6666 */ || __put_user(0x44000002UL, &frame->tramp[1])) /* sc */ goto badframe; flush_icache_range((unsigned long) &frame->tramp[0], (unsigned long) &frame->tramp[2]); current->thread.fpscr = 0; /* turn off all fp exceptions */ /* Retrieve rt_sigframe from stack and set up registers for signal handler */ newsp -= __SIGNAL_FRAMESIZE; if (put_user(regs->gpr[1], (unsigned long *)newsp) || get_user(regs->nip, &rt_sf->uc.uc_mcontext.handler) || get_user(regs->gpr[3], &rt_sf->uc.uc_mcontext.signal) || get_user(regs->gpr[4], (unsigned long *)&rt_sf->pinfo) || get_user(regs->gpr[5], (unsigned long *)&rt_sf->puc)) goto badframe; regs->gpr[1] = newsp; regs->gpr[6] = (unsigned long) rt_sf; regs->link = (unsigned long) frame->tramp; return; badframe: #if DEBUG_SIG printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n", regs, frame, newsp); #endif do_exit(SIGSEGV); } /* * Do a signal return; undo the signal stack. */ int sys_sigreturn(struct pt_regs *regs) { struct sigcontext_struct *sc, sigctx; struct sigregs *sr; int ret; elf_gregset_t saved_regs; /* an array of ELF_NGREG unsigned longs */ sigset_t set; unsigned long prevsp; sc = (struct sigcontext_struct *)(regs->gpr[1] + __SIGNAL_FRAMESIZE); if (copy_from_user(&sigctx, sc, sizeof(sigctx))) goto badframe; set.sig[0] = sigctx.oldmask; #if _NSIG_WORDS > 1 set.sig[1] = sigctx._unused[3]; #endif sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); current->blocked = set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); if (regs->msr & MSR_FP ) giveup_fpu(current); sc++; /* Look at next sigcontext */ if (sc == (struct sigcontext_struct *)(sigctx.regs)) { /* Last stacked signal - restore registers */ sr = (struct sigregs *) sigctx.regs; if (copy_from_user(saved_regs, &sr->gp_regs, sizeof(sr->gp_regs))) goto badframe; saved_regs[PT_MSR] = (regs->msr & ~MSR_USERCHANGE) | (saved_regs[PT_MSR] & MSR_USERCHANGE); memcpy(regs, saved_regs, GP_REGS_SIZE); if (copy_from_user(current->thread.fpr, &sr->fp_regs, sizeof(sr->fp_regs))) goto badframe; ret = regs->result; } else { /* More signals to go */ regs->gpr[1] = (unsigned long)sc - __SIGNAL_FRAMESIZE; if (copy_from_user(&sigctx, sc, sizeof(sigctx))) goto badframe; sr = (struct sigregs *) sigctx.regs; regs->gpr[3] = ret = sigctx.signal; regs->gpr[4] = (unsigned long) sc; regs->link = (unsigned long) &sr->tramp; regs->nip = sigctx.handler; if (get_user(prevsp, &sr->gp_regs[PT_R1]) || put_user(prevsp, (unsigned long *) regs->gpr[1])) goto badframe; current->thread.fpscr = 0; } return ret; badframe: do_exit(SIGSEGV); } /* * Set up a signal frame. */ static void setup_frame(struct pt_regs *regs, struct sigregs *frame, unsigned long newsp) { struct sigcontext_struct *sc = (struct sigcontext_struct *) newsp; if (verify_area(VERIFY_WRITE, frame, sizeof(*frame))) goto badframe; if (regs->msr & MSR_FP) giveup_fpu(current); if (__copy_to_user(&frame->gp_regs, regs, GP_REGS_SIZE) || __copy_to_user(&frame->fp_regs, current->thread.fpr, ELF_NFPREG * sizeof(double)) || __put_user(0x38007777UL, &frame->tramp[0]) /* li r0,0x7777 */ || __put_user(0x44000002UL, &frame->tramp[1])) /* sc */ goto badframe; flush_icache_range((unsigned long) &frame->tramp[0], (unsigned long) &frame->tramp[2]); current->thread.fpscr = 0; /* turn off all fp exceptions */ newsp -= __SIGNAL_FRAMESIZE; if (put_user(regs->gpr[1], (unsigned long *)newsp) || get_user(regs->nip, &sc->handler) || get_user(regs->gpr[3], &sc->signal)) goto badframe; regs->gpr[1] = newsp; regs->gpr[4] = (unsigned long) sc; regs->link = (unsigned long) frame->tramp; return; badframe: #if DEBUG_SIG printk("badframe in setup_frame, regs=%p frame=%p newsp=%lx\n", regs, frame, newsp); #endif do_exit(SIGSEGV); } /* * OK, we're invoking a handler */ static void handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset, struct pt_regs * regs, unsigned long *newspp, unsigned long frame) { struct sigcontext_struct *sc; struct rt_sigframe *rt_sf; if (regs->trap == 0x0C00 /* System Call! */ && ((int)regs->result == -ERESTARTNOHAND || ((int)regs->result == -ERESTARTSYS && !(ka->sa.sa_flags & SA_RESTART)))) regs->result = -EINTR; /* Set up Signal Frame */ if (ka->sa.sa_flags & SA_SIGINFO) { /* Put a Real Time Context onto stack */ *newspp -= sizeof(*rt_sf); rt_sf = (struct rt_sigframe *) *newspp; if (verify_area(VERIFY_WRITE, rt_sf, sizeof(*rt_sf))) goto badframe; if (__put_user((unsigned long) ka->sa.sa_handler, &rt_sf->uc.uc_mcontext.handler) || __put_user(&rt_sf->info, &rt_sf->pinfo) || __put_user(&rt_sf->uc, &rt_sf->puc) /* Put the siginfo */ || __copy_to_user(&rt_sf->info, info, sizeof(*info)) /* Create the ucontext */ || __put_user(0, &rt_sf->uc.uc_flags) || __put_user(0, &rt_sf->uc.uc_link) || __put_user(current->sas_ss_sp, &rt_sf->uc.uc_stack.ss_sp) || __put_user(sas_ss_flags(regs->gpr[1]), &rt_sf->uc.uc_stack.ss_flags) || __put_user(current->sas_ss_size, &rt_sf->uc.uc_stack.ss_size) || __copy_to_user(&rt_sf->uc.uc_sigmask, oldset, sizeof(*oldset)) /* mcontext.regs points to preamble register frame */ || __put_user((struct pt_regs *)frame, &rt_sf->uc.uc_mcontext.regs) || __put_user(sig, &rt_sf->uc.uc_mcontext.signal)) goto badframe; } else { /* Put another sigcontext on the stack */ *newspp -= sizeof(*sc); sc = (struct sigcontext_struct *) *newspp; if (verify_area(VERIFY_WRITE, sc, sizeof(*sc))) goto badframe; if (__put_user((unsigned long) ka->sa.sa_handler, &sc->handler) || __put_user(oldset->sig[0], &sc->oldmask) #if _NSIG_WORDS > 1 || __put_user(oldset->sig[1], &sc->_unused[3]) #endif || __put_user((struct pt_regs *)frame, &sc->regs) || __put_user(sig, &sc->signal)) goto badframe; } if (ka->sa.sa_flags & SA_ONESHOT) ka->sa.sa_handler = SIG_DFL; if (!(ka->sa.sa_flags & SA_NODEFER)) { spin_lock_irq(¤t->sigmask_lock); sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); sigaddset(¤t->blocked,sig); recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); } return; badframe: #if DEBUG_SIG printk("badframe in handle_signal, regs=%p frame=%lx newsp=%lx\n", regs, frame, *newspp); printk("sc=%p sig=%d ka=%p info=%p oldset=%p\n", sc, sig, ka, info, oldset); #endif do_exit(SIGSEGV); } /* * Note that 'init' is a special process: it doesn't get signals it doesn't * want to handle. Thus you cannot kill init even with a SIGKILL even by * mistake. */ int do_signal(sigset_t *oldset, struct pt_regs *regs) { siginfo_t info; struct k_sigaction *ka; unsigned long frame, newsp; if (!oldset) oldset = ¤t->blocked; newsp = frame = 0; for (;;) { unsigned long signr; spin_lock_irq(¤t->sigmask_lock); signr = dequeue_signal(¤t->blocked, &info); spin_unlock_irq(¤t->sigmask_lock); if (!signr) break; if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) { /* Let the debugger run. */ current->exit_code = signr; current->state = TASK_STOPPED; notify_parent(current, SIGCHLD); schedule(); /* We're back. Did the debugger cancel the sig? */ if (!(signr = current->exit_code)) continue; current->exit_code = 0; /* The debugger continued. Ignore SIGSTOP. */ if (signr == SIGSTOP) continue; /* Update the siginfo structure. Is this good? */ if (signr != info.si_signo) { info.si_signo = signr; info.si_errno = 0; info.si_code = SI_USER; info.si_pid = current->p_pptr->pid; info.si_uid = current->p_pptr->uid; } /* If the (new) signal is now blocked, requeue it. */ if (sigismember(¤t->blocked, signr)) { send_sig_info(signr, &info, current); continue; } } ka = ¤t->sig->action[signr-1]; if (ka->sa.sa_handler == SIG_IGN) { if (signr != SIGCHLD) continue; /* Check for SIGCHLD: it's special. */ while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0) /* nothing */; continue; } if (ka->sa.sa_handler == SIG_DFL) { int exit_code = signr; /* Init gets no signals it doesn't want. */ if (current->pid == 1) continue; switch (signr) { case SIGCONT: case SIGCHLD: case SIGWINCH: continue; case SIGTSTP: case SIGTTIN: case SIGTTOU: if (is_orphaned_pgrp(current->pgrp)) continue; /* FALLTHRU */ case SIGSTOP: current->state = TASK_STOPPED; current->exit_code = signr; if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) notify_parent(current, SIGCHLD); schedule(); continue; case SIGQUIT: case SIGILL: case SIGTRAP: case SIGABRT: case SIGFPE: case SIGSEGV: case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ: if (do_coredump(signr, regs)) exit_code |= 0x80; /* FALLTHRU */ default: sigaddset(¤t->pending.signal, signr); recalc_sigpending(current); current->flags |= PF_SIGNALED; do_exit(exit_code); /* NOTREACHED */ } } if ( (ka->sa.sa_flags & SA_ONSTACK) && (! on_sig_stack(regs->gpr[1]))) newsp = (current->sas_ss_sp + current->sas_ss_size); else newsp = regs->gpr[1]; newsp = frame = newsp - sizeof(struct sigregs); /* Whee! Actually deliver the signal. */ handle_signal(signr, ka, &info, oldset, regs, &newsp, frame); break; } if (regs->trap == 0x0C00 /* System Call! */ && ((int)regs->result == -ERESTARTNOHAND || (int)regs->result == -ERESTARTSYS || (int)regs->result == -ERESTARTNOINTR)) { regs->gpr[3] = regs->orig_gpr3; regs->nip -= 4; /* Back up & retry system call */ regs->result = 0; } if (newsp == frame) return 0; /* no signals delivered */ if (ka->sa.sa_flags & SA_SIGINFO) setup_rt_frame(regs, (struct sigregs *) frame, newsp); else setup_frame(regs, (struct sigregs *) frame, newsp); return 1; }