/* * linux/arch/ppc64/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 #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)) #define FP_REGS_SIZE sizeof(elf_fpregset_t) #define TRAMP_TRACEBACK 3 #define TRAMP_SIZE 6 /* * When we have signals to deliver, we set up on the user stack, * going down from the original stack pointer: * 1) a sigframe/rt_sigframe struct which contains the sigcontext/ucontext * 2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller * frame for the signal handler. */ struct sigframe { /* sys_sigreturn requires the sigcontext be the first field */ struct sigcontext sc; unsigned int tramp[TRAMP_SIZE]; /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */ char abigap[288]; }; struct rt_sigframe { /* sys_rt_sigreturn requires the ucontext be the first field */ struct ucontext uc; unsigned long _unused[2]; unsigned int tramp[TRAMP_SIZE]; struct siginfo *pinfo; void *puc; struct siginfo info; /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */ char abigap[288]; }; extern long sys_wait4(pid_t pid, unsigned int *stat_addr, int options, /*unsigned long*/ struct rusage *ru); 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: err |= __put_user(from->si_addr, &to->si_addr); 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; } } int do_signal(sigset_t *oldset, struct pt_regs *regs); /* * Atomically swap in the new signal mask, and wait for a signal. */ asmlinkage long 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->result = -EINTR; regs->gpr[3] = EINTR; regs->ccr |= 0x10000000; 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]; } } asmlinkage long 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->result = -EINTR; regs->gpr[3] = EINTR; regs->ccr |= 0x10000000; while (1) { current->state = TASK_INTERRUPTIBLE; schedule(); if (do_signal(&saveset, regs)) return regs->gpr[3]; } } asmlinkage long sys_sigaltstack(const stack_t *uss, stack_t *uoss, unsigned long r5, unsigned long r6, unsigned long r7, unsigned long r8, struct pt_regs *regs) { return do_sigaltstack(uss, uoss, regs->gpr[1]); } asmlinkage long 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; } /* * Set up the sigcontext for the signal frame. */ static int setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs, int signr, sigset_t *set, unsigned long handler) { int err = 0; if (regs->msr & MSR_FP) giveup_fpu(current); current->thread.saved_msr = regs->msr & ~(MSR_FP | MSR_FE0 | MSR_FE1); regs->msr = current->thread.saved_msr | current->thread.fpexc_mode; current->thread.saved_softe = regs->softe; err |= __put_user(&sc->gp_regs, &sc->regs); err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE); err |= __copy_to_user(&sc->fp_regs, ¤t->thread.fpr, FP_REGS_SIZE); err |= __put_user(signr, &sc->signal); err |= __put_user(handler, &sc->handler); if (set != NULL) err |= __put_user(set->sig[0], &sc->oldmask); regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1); current->thread.fpscr = 0; return err; } /* * Restore the sigcontext from the signal frame. */ static int restore_sigcontext(struct pt_regs *regs, sigset_t *set, struct sigcontext *sc) { unsigned int err = 0; if (regs->msr & MSR_FP) giveup_fpu(current); err |= __copy_from_user(regs, &sc->gp_regs, GP_REGS_SIZE); err |= __copy_from_user(¤t->thread.fpr, &sc->fp_regs, FP_REGS_SIZE); current->thread.fpexc_mode = regs->msr & (MSR_FE0 | MSR_FE1); if (set != NULL) err |= __get_user(set->sig[0], &sc->oldmask); /* Don't allow the signal handler to change these modulo FE{0,1} */ regs->msr = current->thread.saved_msr & ~(MSR_FP | MSR_FE0 | MSR_FE1); regs->softe = current->thread.saved_softe; return err; } /* * Allocate space for the signal frame */ static inline void * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size) { unsigned long newsp; /* Default to using normal stack */ newsp = regs->gpr[1]; if (ka->sa.sa_flags & SA_ONSTACK) { if (! on_sig_stack(regs->gpr[1])) newsp = (current->sas_ss_sp + current->sas_ss_size); } /* The ABI requires quadword alignment for the stack. */ return (void *)((newsp - frame_size) & -16ul); } static int setup_trampoline(unsigned int syscall, unsigned int *tramp) { int i, err = 0; /* addi r1, r1, __SIGNAL_FRAMESIZE # Pop the dummy stackframe */ err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]); /* li r0, __NR_[rt_]sigreturn| */ err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]); /* sc */ err |= __put_user(0x44000002UL, &tramp[2]); /* Minimal traceback info */ for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++) err |= __put_user(0, &tramp[i]); if (!err) flush_icache_range((unsigned long) &tramp[0], (unsigned long) &tramp[TRAMP_SIZE]); return err; } asmlinkage int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, unsigned long r8, struct pt_regs *regs) { struct ucontext *uc = (struct ucontext *)regs->gpr[1]; sigset_t set; stack_t st; if (verify_area(VERIFY_READ, uc, sizeof(*uc))) goto badframe; if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); current->blocked = set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); if (restore_sigcontext(regs, NULL, &uc->uc_mcontext)) goto badframe; if (__copy_from_user(&st, &uc->uc_stack, sizeof(st))) goto badframe; /* This function sets back the stack flags into the current task structure. */ sys_sigaltstack(&st, NULL, 0, 0, 0, 0, regs); return regs->result; badframe: do_exit(SIGSEGV); } static void setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs *regs) { /* Handler is *really* a pointer to the function descriptor for * the signal routine. The first entry in the function * descriptor is the entry address of signal and the second * entry is the TOC value we need to use. */ func_descr_t *funct_desc_ptr; struct rt_sigframe *frame; unsigned long newsp; int err = 0; frame = get_sigframe(ka, regs, sizeof(*frame)); if (verify_area(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; err |= __put_user(&frame->info, &frame->pinfo); err |= __put_user(&frame->uc, &frame->puc); err |= copy_siginfo_to_user(&frame->info, info); if (err) goto give_sigsegv; /* Create the ucontext. */ err |= __put_user(0, &frame->uc.uc_flags); err |= __put_user(0, &frame->uc.uc_link); err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); err |= __put_user(sas_ss_flags(regs->gpr[1]), &frame->uc.uc_stack.ss_flags); err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, signr, NULL, (unsigned long)ka->sa.sa_handler); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); if (err) goto give_sigsegv; /* Set up to return from userspace. */ err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]); if (err) goto give_sigsegv; funct_desc_ptr = (func_descr_t *) ka->sa.sa_handler; /* Allocate a dummy caller frame for the signal handler. */ newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE; err |= put_user(0, (unsigned long *)newsp); /* Set up "regs" so we "return" to the signal handler. */ err |= get_user(regs->nip, &funct_desc_ptr->entry); regs->link = (unsigned long) &frame->tramp[0]; regs->gpr[1] = newsp; err |= get_user(regs->gpr[2], &funct_desc_ptr->toc); regs->gpr[3] = signr; err |= get_user(regs->gpr[4], (unsigned long *)&frame->pinfo); err |= get_user(regs->gpr[5], (unsigned long *)&frame->puc); regs->gpr[6] = (unsigned long) frame; if (err) goto give_sigsegv; return; give_sigsegv: #if DEBUG_SIG printk("badframe in setup_rt_frame, regs=%p frame=%p, newsp=0x%lx\n", regs, frame, newsp); #endif do_exit(SIGSEGV); } /* * Do a signal return; undo the signal stack. */ asmlinkage long sys_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5, unsigned long r6, unsigned long r7, unsigned long r8, struct pt_regs *regs) { struct sigcontext *sc = (struct sigcontext *)regs->gpr[1]; sigset_t set; if (verify_area(VERIFY_READ, sc, sizeof(*sc))) goto badframe; if (restore_sigcontext(regs, &set, sc)) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); current->blocked = set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); return regs->result; badframe: do_exit(SIGSEGV); } static void setup_frame(int signr, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs) { /* Handler is *really* a pointer to the function descriptor for * the signal routine. The first entry in the function * descriptor is the entry address of signal and the second * entry is the TOC value we need to use. */ func_descr_t *funct_desc_ptr; struct sigframe *frame; unsigned long newsp; int err = 0; frame = get_sigframe(ka, regs, sizeof(*frame)); if (verify_area(VERIFY_WRITE, frame, sizeof(*frame))) goto badframe; err |= setup_sigcontext(&frame->sc, regs, signr, set, (unsigned long)ka->sa.sa_handler); /* Set up to return from userspace. */ err |= setup_trampoline(__NR_sigreturn, &frame->tramp[0]); if (err) goto badframe; funct_desc_ptr = (func_descr_t *) ka->sa.sa_handler; /* Allocate a dummy caller frame for the signal handler. */ newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE; err |= put_user(0, (unsigned long *)newsp); /* Set up "regs" so we "return" to the signal handler. */ err |= get_user(regs->nip, &funct_desc_ptr->entry); regs->link = (unsigned long) &frame->tramp[0]; regs->gpr[1] = newsp; err |= get_user(regs->gpr[2], &funct_desc_ptr->toc); regs->gpr[3] = signr; regs->gpr[4] = (unsigned long) &frame->sc; if (err) goto badframe; 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) { /* Set up Signal Frame */ if (ka->sa.sa_flags & SA_SIGINFO) setup_rt_frame(sig, ka, info, oldset, regs); else setup_frame(sig, ka, oldset, regs); 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); } } static inline void syscall_restart(struct pt_regs *regs, struct k_sigaction *ka) { switch ((int)regs->result) { case -ERESTARTNOHAND: /* ERESTARTNOHAND means that the syscall should only be restarted if there was no handler for the signal, and since we only get here if there is a handler, we dont restart */ regs->result = -EINTR; break; case -ERESTARTSYS: /* ERESTARTSYS means to restart the syscall if there is no handler or the handler was registered with SA_RESTART */ if (!(ka->sa.sa_flags & SA_RESTART)) { regs->result = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: /* ERESTARTNOINTR means that the syscall should be called again after the signal handler returns */ regs->gpr[3] = regs->orig_gpr3; regs->nip -= 4; regs->result = 0; } } static int get_signal_to_deliver(siginfo_t *info, struct pt_regs *regs) { for (;;) { unsigned long signr; struct k_sigaction *ka; 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? */ signr = current->exit_code; if (signr == 0) 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: case SIGURG: continue; case SIGTSTP: case SIGTTIN: case SIGTTOU: if (is_orphaned_pgrp(current->pgrp)) continue; /* FALLTHRU */ case SIGSTOP: { struct signal_struct *sig; current->state = TASK_STOPPED; current->exit_code = signr; sig = current->p_pptr->sig; if (sig && !(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: sig_exit(signr, exit_code, info); /* NOTREACHED */ } } return signr; } return 0; } /* * 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. */ extern int do_signal32(sigset_t *oldset, struct pt_regs *regs); int do_signal(sigset_t *oldset, struct pt_regs *regs) { siginfo_t info; int signr; /* * If the current thread is 32 bit - invoke the * 32 bit signal handling code */ if (current->thread.flags & PPC_FLAG_32BIT) return do_signal32(oldset, regs); if (!oldset) oldset = ¤t->blocked; signr = get_signal_to_deliver(&info, regs); if (signr > 0) { struct k_sigaction *ka = ¤t->sig->action[signr-1]; /* Whee! Actually deliver the signal. */ if (regs->trap == 0x0C00) syscall_restart(regs, ka); handle_signal(signr, ka, &info, oldset, regs); return 1; } 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; } return 0; }