/* * 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)) extern void syscall_direct_return(struct pt_regs *regs); 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->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]; } } 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->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]; } } int sys_sigaltstack(const stack_t *uss, stack_t *uoss, int r5, int r6, int r7, int r8, struct pt_regs *regs) { 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 * a sigcontext struct * a gap of __SIGNAL_FRAMESIZE bytes * * Each of these things must be a multiple of 16 bytes in size. * */ struct sigregs { struct mcontext mctx; /* all the register values */ /* 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]; }; /* We use the mc_pad field for the signal return trampoline. */ #define tramp mc_pad /* * When we have rt signals to deliver, we set up on the * user stack, going down from the original stack pointer: * one rt_sigframe struct (siginfo + ucontext + ABI gap) * a gap of __SIGNAL_FRAMESIZE+16 bytes * (the +16 is to get the siginfo and ucontext in the same * positions as in older kernels). * * Each of these things must be a multiple of 16 bytes in size. * */ struct rt_sigframe { struct siginfo info; struct ucontext uc; /* 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]; }; /* * Save the current user registers on the user stack. * We only save the altivec registers if the process has used * altivec instructions at some point. */ static int save_user_regs(struct pt_regs *regs, struct mcontext *frame, int sigret) { /* save general and floating-point registers */ if (regs->msr & MSR_FP) giveup_fpu(current); if (__copy_to_user(&frame->mc_gregs, regs, GP_REGS_SIZE) || __copy_to_user(&frame->mc_fregs, current->thread.fpr, ELF_NFPREG * sizeof(double))) return 1; current->thread.fpscr = 0; /* turn off all fp exceptions */ #ifdef CONFIG_ALTIVEC /* save altivec registers */ if (current->thread.used_vr) { if (regs->msr & MSR_VEC) giveup_altivec(current); if (__copy_to_user(&frame->mc_vregs, current->thread.vr, ELF_NVRREG * sizeof(vector128))) return 1; /* set MSR_VEC in the saved MSR value to indicate that frame->mc_vregs contains valid data */ if (__put_user(regs->msr | MSR_VEC, &frame->mc_gregs[PT_MSR])) return 1; } /* else assert((regs->msr & MSR_VEC) == 0) */ /* We always copy to/from vrsave, it's 0 if we don't have or don't * use altivec. Since VSCR only contains 32 bits saved in the least * significant bits of a vector, we "cheat" and stuff VRSAVE in the * most significant bits of that same vector. --BenH */ if (__put_user(current->thread.vrsave, (u32 *)&frame->mc_vregs[32])) return 1; #endif /* CONFIG_ALTIVEC */ if (sigret) { /* Set up the sigreturn trampoline: li r0,sigret; sc */ if (__put_user(0x38000000UL + sigret, &frame->tramp[0]) || __put_user(0x44000002UL, &frame->tramp[1])) return 1; flush_icache_range((unsigned long) &frame->tramp[0], (unsigned long) &frame->tramp[2]); } return 0; } /* * Restore the current user register values from the user stack, * (except for MSR). */ static int restore_user_regs(struct pt_regs *regs, struct mcontext *sr) { #ifdef CONFIG_ALTIVEC unsigned long msr; #endif /* copy up to but not including MSR */ if (__copy_from_user(regs, &sr->mc_gregs, PT_MSR * sizeof(elf_greg_t))) return 1; /* copy from orig_r3 (the word after the MSR) up to the end */ if (__copy_from_user(®s->orig_gpr3, &sr->mc_gregs[PT_ORIG_R3], GP_REGS_SIZE - PT_ORIG_R3 * sizeof(elf_greg_t))) return 1; /* force the process to reload the FP registers from current->thread when it next does FP instructions */ regs->msr &= ~MSR_FP; if (__copy_from_user(current->thread.fpr, &sr->mc_fregs, sizeof(sr->mc_fregs))) return 1; #ifdef CONFIG_ALTIVEC /* force the process to reload the altivec registers from current->thread when it next does altivec instructions */ regs->msr &= ~MSR_VEC; if (!__get_user(msr, &sr->mc_gregs[PT_MSR]) && (msr & MSR_VEC) != 0) { /* restore altivec registers from the stack */ if (__copy_from_user(current->thread.vr, &sr->mc_vregs, sizeof(sr->mc_vregs))) return 1; } else if (current->thread.used_vr) memset(¤t->thread.vr, 0, ELF_NVRREG * sizeof(vector128)); /* Always get VRSAVE back */ if (__get_user(current->thread.vrsave, (u32 *)&sr->mc_vregs[32])) return 1; #endif /* CONFIG_ALTIVEC */ return 0; } /* * Restore the user process's signal mask */ static void restore_sigmask(sigset_t *set) { sigdelsetmask(set, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); current->blocked = *set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); } /* * Set up a signal frame for a "real-time" signal handler * (one which gets siginfo). */ static void handle_rt_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset, struct pt_regs * regs, unsigned long newsp) { struct rt_sigframe *rt_sf; struct mcontext *frame; unsigned long origsp = newsp; /* Set up Signal Frame */ /* Put a Real Time Context onto stack */ newsp -= sizeof(*rt_sf); rt_sf = (struct rt_sigframe *) newsp; /* create a stack frame for the caller of the handler */ newsp -= __SIGNAL_FRAMESIZE + 16; if (verify_area(VERIFY_WRITE, (void *) newsp, origsp - newsp)) goto badframe; /* Put the siginfo & fill in most of the ucontext */ if (__copy_to_user(&rt_sf->info, info, sizeof(*info)) || __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) || __put_user(&rt_sf->uc.uc_mcontext, &rt_sf->uc.uc_regs) || __copy_to_user(&rt_sf->uc.uc_sigmask, oldset, sizeof(*oldset))) goto badframe; /* Save user registers on the stack */ frame = &rt_sf->uc.uc_mcontext; if (save_user_regs(regs, frame, 0x6666)) goto badframe; if (put_user(regs->gpr[1], (unsigned long *)newsp)) goto badframe; regs->gpr[1] = newsp; regs->gpr[3] = sig; regs->gpr[4] = (unsigned long) &rt_sf->info; regs->gpr[5] = (unsigned long) &rt_sf->uc; regs->gpr[6] = (unsigned long) rt_sf; regs->nip = (unsigned long) ka->sa.sa_handler; regs->link = (unsigned long) frame->tramp; return; badframe: #if DEBUG_SIG printk("badframe in handle_rt_signal, regs=%p frame=%p newsp=%lx\n", regs, frame, newsp); #endif if (sig == SIGSEGV) ka->sa.sa_handler = SIG_DFL; force_sig(SIGSEGV, current); } static int do_setcontext(struct ucontext *ucp, struct pt_regs *regs) { sigset_t set; struct mcontext *mcp; if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(set)) || __get_user(mcp, &ucp->uc_regs)) return -EFAULT; restore_sigmask(&set); if (restore_user_regs(regs, mcp)) return -EFAULT; return 0; } int sys_swapcontext(struct ucontext *old_ctx, struct ucontext *new_ctx, int r5, int r6, int r7, int r8, struct pt_regs *regs) { unsigned char tmp; if (old_ctx != NULL) { if (verify_area(VERIFY_WRITE, old_ctx, sizeof(*old_ctx)) || save_user_regs(regs, &old_ctx->uc_mcontext, 0) || __copy_to_user(&old_ctx->uc_sigmask, ¤t->blocked, sizeof(sigset_t)) || __put_user(&old_ctx->uc_mcontext, &old_ctx->uc_regs)) return -EFAULT; } if (new_ctx == NULL) return 0; if (verify_area(VERIFY_READ, new_ctx, sizeof(*new_ctx)) || __get_user(tmp, (u8 *) new_ctx) || __get_user(tmp, (u8 *) (new_ctx + 1) - 1)) return -EFAULT; /* * If we get a fault copying the context into the kernel's * image of the user's registers, we can't just return -EFAULT * because the user's registers will be corrupted. For instance * the NIP value may have been updated but not some of the * other registers. Given that we have done the verify_area * and successfully read the first and last bytes of the region * above, this should only happen in an out-of-memory situation * or if another thread unmaps the region containing the context. * We kill the task with a SIGSEGV in this situation. */ if (do_setcontext(new_ctx, regs)) do_exit(SIGSEGV); syscall_direct_return(regs); /* doesn't actually return back to here */ return 0; } int sys_rt_sigreturn(struct pt_regs *regs) { struct rt_sigframe *rt_sf; stack_t st; rt_sf = (struct rt_sigframe *)(regs->gpr[1] + __SIGNAL_FRAMESIZE + 16); if (verify_area(VERIFY_READ, rt_sf, sizeof(struct rt_sigframe))) goto bad; if (do_setcontext(&rt_sf->uc, regs)) goto bad; /* * It's not clear whether or why it is desirable to save the * sigaltstack setting on signal delivery and restore it on * signal return. But other architectures do this and we have * always done it up until now so it is probably better not to * change it. -- paulus */ if (__copy_from_user(&st, &rt_sf->uc.uc_stack, sizeof(st))) goto bad; do_sigaltstack(&st, NULL, regs->gpr[1]); return regs->result; bad: force_sig(SIGSEGV, current); return 0; } /* * 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 newsp) { struct sigcontext *sc; struct sigregs *frame; unsigned long origsp = newsp; /* Set up Signal Frame */ newsp -= sizeof(struct sigregs); frame = (struct sigregs *) newsp; /* Put a sigcontext on the stack */ newsp -= sizeof(*sc); sc = (struct sigcontext *) newsp; /* create a stack frame for the caller of the handler */ newsp -= __SIGNAL_FRAMESIZE; if (verify_area(VERIFY_WRITE, (void *) newsp, origsp - newsp)) goto badframe; #if _NSIG != 64 #error "Please adjust handle_signal()" #endif if (__put_user((unsigned long) ka->sa.sa_handler, &sc->handler) || __put_user(oldset->sig[0], &sc->oldmask) || __put_user(oldset->sig[1], &sc->_unused[3]) || __put_user((struct pt_regs *)frame, &sc->regs) || __put_user(sig, &sc->signal)) goto badframe; if (save_user_regs(regs, &frame->mctx, 0x7777)) goto badframe; if (put_user(regs->gpr[1], (unsigned long *)newsp)) goto badframe; regs->gpr[1] = newsp; regs->gpr[3] = sig; regs->gpr[4] = (unsigned long) sc; regs->nip = (unsigned long) ka->sa.sa_handler; regs->link = (unsigned long) frame->mctx.tramp; return; badframe: #if DEBUG_SIG printk("badframe in handle_signal, regs=%p frame=%lx newsp=%lx\n", regs, frame, *newspp); #endif if (sig == SIGSEGV) ka->sa.sa_handler = SIG_DFL; force_sig(SIGSEGV, current); } /* * Do a signal return; undo the signal stack. */ int sys_sigreturn(struct pt_regs *regs) { struct sigcontext *sc, sigctx; struct mcontext *sr; int ret; sigset_t set; sc = (struct sigcontext *)(regs->gpr[1] + __SIGNAL_FRAMESIZE); if (copy_from_user(&sigctx, sc, sizeof(sigctx))) goto badframe; set.sig[0] = sigctx.oldmask; set.sig[1] = sigctx._unused[3]; restore_sigmask(&set); sr = (struct mcontext *) sigctx.regs; if (verify_area(VERIFY_READ, sr, sizeof(*sr)) || restore_user_regs(regs, sr)) goto badframe; ret = regs->result; return ret; badframe: force_sig(SIGSEGV, current); return 0; } static int get_signal_to_deliver(struct siginfo *infop, struct pt_regs *regs) { struct k_sigaction *ka; int signr; for (;;) { spin_lock_irq(¤t->sigmask_lock); signr = dequeue_signal(¤t->blocked, infop); spin_unlock_irq(¤t->sigmask_lock); if (!signr) return 0; 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 != infop->si_signo) { infop->si_signo = signr; infop->si_errno = 0; infop->si_code = SI_USER; infop->si_pid = current->p_pptr->pid; infop->si_uid = current->p_pptr->uid; } /* If the (new) signal is now blocked, requeue it. */ if (sigismember(¤t->blocked, signr)) { send_sig_info(signr, infop, 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: 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: sig_exit(signr, exit_code, infop); /* NOTREACHED */ } } return signr; } } /* * 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; int signr; if (!oldset) oldset = ¤t->blocked; newsp = frame = 0; signr = get_signal_to_deliver(&info, regs); ka = (signr == 0)? NULL: ¤t->sig->action[signr-1]; if (regs->trap == 0xc00) { /* system call */ switch ((int) regs->result) { case -ERESTARTSYS: if (signr == 0 || (ka->sa.sa_flags & SA_RESTART)) goto retry; /* fall through */ case -ERESTARTNOHAND: if (signr > 0) { /* make the system call return an EINTR */ regs->result = -EINTR; break; } /* fall through */ case -ERESTARTNOINTR: retry: /* Back up & retry system call */ regs->gpr[3] = regs->orig_gpr3; regs->nip -= 4; regs->result = 0; break; } } if (signr == 0) return 0; /* no signals delivered */ if ((ka->sa.sa_flags & SA_ONSTACK) && current->sas_ss_size && !on_sig_stack(regs->gpr[1])) newsp = current->sas_ss_sp + current->sas_ss_size; else newsp = regs->gpr[1]; newsp &= ~0xfUL; /* Whee! Actually deliver the signal. */ if (ka->sa.sa_flags & SA_SIGINFO) handle_rt_signal(signr, ka, &info, oldset, regs, newsp); else handle_signal(signr, ka, &info, oldset, regs, newsp); 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, signr); recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); } return 1; }