/* signal.c: FRV specific bits of signal handling * * Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * - Derived from arch/m68k/kernel/signal.c * * 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 <linux/sched.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/kernel.h> #include <linux/signal.h> #include <linux/errno.h> #include <linux/wait.h> #include <linux/ptrace.h> #include <linux/unistd.h> #include <linux/personality.h> #include <linux/freezer.h> #include <asm/ucontext.h> #include <asm/uaccess.h> #include <asm/cacheflush.h> #define DEBUG_SIG 0 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) struct fdpic_func_descriptor { unsigned long text; unsigned long GOT; }; /* * Atomically swap in the new signal mask, and wait for a signal. */ asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask) { mask &= _BLOCKABLE; spin_lock_irq(¤t->sighand->siglock); current->saved_sigmask = current->blocked; siginitset(¤t->blocked, mask); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); current->state = TASK_INTERRUPTIBLE; schedule(); set_thread_flag(TIF_RESTORE_SIGMASK); return -ERESTARTNOHAND; } asmlinkage int sys_sigaction(int sig, const struct old_sigaction __user *act, struct old_sigaction __user *oact) { struct k_sigaction new_ka, old_ka; int ret; if (act) { old_sigset_t mask; if (!access_ok(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 (!access_ok(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; } asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss) { return do_sigaltstack(uss, uoss, __frame->sp); } /* * Do a signal return; undo the signal stack. */ struct sigframe { __sigrestore_t pretcode; int sig; struct sigcontext sc; unsigned long extramask[_NSIG_WORDS-1]; uint32_t retcode[2]; }; struct rt_sigframe { __sigrestore_t pretcode; int sig; struct siginfo __user *pinfo; void __user *puc; struct siginfo info; struct ucontext uc; uint32_t retcode[2]; }; static int restore_sigcontext(struct sigcontext __user *sc, int *_gr8) { struct user_context *user = current->thread.user; unsigned long tbr, psr; tbr = user->i.tbr; psr = user->i.psr; if (copy_from_user(user, &sc->sc_context, sizeof(sc->sc_context))) goto badframe; user->i.tbr = tbr; user->i.psr = psr; restore_user_regs(user); user->i.syscallno = -1; /* disable syscall checks */ *_gr8 = user->i.gr[8]; return 0; badframe: return 1; } asmlinkage int sys_sigreturn(void) { struct sigframe __user *frame = (struct sigframe __user *) __frame->sp; sigset_t set; int gr8; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__get_user(set.sig[0], &frame->sc.sc_oldmask)) goto badframe; if (_NSIG_WORDS > 1 && __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); current->blocked = set; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); if (restore_sigcontext(&frame->sc, &gr8)) goto badframe; return gr8; badframe: force_sig(SIGSEGV, current); return 0; } asmlinkage int sys_rt_sigreturn(void) { struct rt_sigframe __user *frame = (struct rt_sigframe __user *) __frame->sp; sigset_t set; int gr8; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sighand->siglock); current->blocked = set; recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); if (restore_sigcontext(&frame->uc.uc_mcontext, &gr8)) goto badframe; if (do_sigaltstack(&frame->uc.uc_stack, NULL, __frame->sp) == -EFAULT) goto badframe; return gr8; badframe: force_sig(SIGSEGV, current); return 0; } /* * Set up a signal frame */ static int setup_sigcontext(struct sigcontext __user *sc, unsigned long mask) { save_user_regs(current->thread.user); if (copy_to_user(&sc->sc_context, current->thread.user, sizeof(sc->sc_context)) != 0) goto badframe; /* non-iBCS2 extensions.. */ if (__put_user(mask, &sc->sc_oldmask) < 0) goto badframe; return 0; badframe: return 1; } /*****************************************************************************/ /* * Determine which stack to use.. */ static inline void __user *get_sigframe(struct k_sigaction *ka, size_t frame_size) { unsigned long sp; /* Default to using normal stack */ sp = __frame->sp; /* This is the X/Open sanctioned signal stack switching. */ if (ka->sa.sa_flags & SA_ONSTACK) { if (! sas_ss_flags(sp)) sp = current->sas_ss_sp + current->sas_ss_size; } return (void __user *) ((sp - frame_size) & ~7UL); } /* end get_sigframe() */ /*****************************************************************************/ /* * */ static int setup_frame(int sig, struct k_sigaction *ka, sigset_t *set) { struct sigframe __user *frame; int rsig; frame = get_sigframe(ka, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; rsig = sig; if (sig < 32 && __current_thread_info->exec_domain && __current_thread_info->exec_domain->signal_invmap) rsig = __current_thread_info->exec_domain->signal_invmap[sig]; if (__put_user(rsig, &frame->sig) < 0) goto give_sigsegv; if (setup_sigcontext(&frame->sc, set->sig[0])) goto give_sigsegv; if (_NSIG_WORDS > 1) { if (__copy_to_user(frame->extramask, &set->sig[1], sizeof(frame->extramask))) goto give_sigsegv; } /* Set up to return from userspace. If provided, use a stub * already in userspace. */ if (ka->sa.sa_flags & SA_RESTORER) { if (__put_user(ka->sa.sa_restorer, &frame->pretcode) < 0) goto give_sigsegv; } else { /* Set up the following code on the stack: * setlos #__NR_sigreturn,gr7 * tira gr0,0 */ if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) || __put_user(0x8efc0000|__NR_sigreturn, &frame->retcode[0]) || __put_user(0xc0700000, &frame->retcode[1])) goto give_sigsegv; flush_icache_range((unsigned long) frame->retcode, (unsigned long) (frame->retcode + 2)); } /* set up registers for signal handler */ __frame->sp = (unsigned long) frame; __frame->lr = (unsigned long) &frame->retcode; __frame->gr8 = sig; if (current->personality & FDPIC_FUNCPTRS) { struct fdpic_func_descriptor __user *funcptr = (struct fdpic_func_descriptor __user *) ka->sa.sa_handler; __get_user(__frame->pc, &funcptr->text); __get_user(__frame->gr15, &funcptr->GOT); } else { __frame->pc = (unsigned long) ka->sa.sa_handler; __frame->gr15 = 0; } set_fs(USER_DS); /* the tracer may want to single-step inside the handler */ if (test_thread_flag(TIF_SINGLESTEP)) ptrace_notify(SIGTRAP); #if DEBUG_SIG printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n", sig, current->comm, current->pid, frame, __frame->pc, frame->pretcode); #endif return 0; give_sigsegv: force_sig(SIGSEGV, current); return -EFAULT; } /* end setup_frame() */ /*****************************************************************************/ /* * */ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set) { struct rt_sigframe __user *frame; int rsig; frame = get_sigframe(ka, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; rsig = sig; if (sig < 32 && __current_thread_info->exec_domain && __current_thread_info->exec_domain->signal_invmap) rsig = __current_thread_info->exec_domain->signal_invmap[sig]; if (__put_user(rsig, &frame->sig) || __put_user(&frame->info, &frame->pinfo) || __put_user(&frame->uc, &frame->puc)) goto give_sigsegv; if (copy_siginfo_to_user(&frame->info, info)) goto give_sigsegv; /* Create the ucontext. */ if (__put_user(0, &frame->uc.uc_flags) || __put_user(NULL, &frame->uc.uc_link) || __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp) || __put_user(sas_ss_flags(__frame->sp), &frame->uc.uc_stack.ss_flags) || __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size)) goto give_sigsegv; if (setup_sigcontext(&frame->uc.uc_mcontext, set->sig[0])) goto give_sigsegv; if (__copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set))) goto give_sigsegv; /* Set up to return from userspace. If provided, use a stub * already in userspace. */ if (ka->sa.sa_flags & SA_RESTORER) { if (__put_user(ka->sa.sa_restorer, &frame->pretcode)) goto give_sigsegv; } else { /* Set up the following code on the stack: * setlos #__NR_sigreturn,gr7 * tira gr0,0 */ if (__put_user((__sigrestore_t)frame->retcode, &frame->pretcode) || __put_user(0x8efc0000|__NR_rt_sigreturn, &frame->retcode[0]) || __put_user(0xc0700000, &frame->retcode[1])) goto give_sigsegv; flush_icache_range((unsigned long) frame->retcode, (unsigned long) (frame->retcode + 2)); } /* Set up registers for signal handler */ __frame->sp = (unsigned long) frame; __frame->lr = (unsigned long) &frame->retcode; __frame->gr8 = sig; __frame->gr9 = (unsigned long) &frame->info; if (current->personality & FDPIC_FUNCPTRS) { struct fdpic_func_descriptor __user *funcptr = (struct fdpic_func_descriptor __user *) ka->sa.sa_handler; __get_user(__frame->pc, &funcptr->text); __get_user(__frame->gr15, &funcptr->GOT); } else { __frame->pc = (unsigned long) ka->sa.sa_handler; __frame->gr15 = 0; } set_fs(USER_DS); /* the tracer may want to single-step inside the handler */ if (test_thread_flag(TIF_SINGLESTEP)) ptrace_notify(SIGTRAP); #if DEBUG_SIG printk("SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n", sig, current->comm, current->pid, frame, __frame->pc, frame->pretcode); #endif return 0; give_sigsegv: force_sig(SIGSEGV, current); return -EFAULT; } /* end setup_rt_frame() */ /*****************************************************************************/ /* * OK, we're invoking a handler */ static int handle_signal(unsigned long sig, siginfo_t *info, struct k_sigaction *ka, sigset_t *oldset) { int ret; /* Are we from a system call? */ if (in_syscall(__frame)) { /* If so, check system call restarting.. */ switch (__frame->gr8) { case -ERESTART_RESTARTBLOCK: case -ERESTARTNOHAND: __frame->gr8 = -EINTR; break; case -ERESTARTSYS: if (!(ka->sa.sa_flags & SA_RESTART)) { __frame->gr8 = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: __frame->gr8 = __frame->orig_gr8; __frame->pc -= 4; } } /* Set up the stack frame */ if (ka->sa.sa_flags & SA_SIGINFO) ret = setup_rt_frame(sig, ka, info, oldset); else ret = setup_frame(sig, ka, oldset); if (ret == 0) { spin_lock_irq(¤t->sighand->siglock); sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask); if (!(ka->sa.sa_flags & SA_NODEFER)) sigaddset(¤t->blocked, sig); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); } return ret; } /* end handle_signal() */ /*****************************************************************************/ /* * 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. */ static void do_signal(void) { struct k_sigaction ka; siginfo_t info; sigset_t *oldset; int signr; /* * We want the common case to go fast, which * is why we may in certain cases get here from * kernel mode. Just return without doing anything * if so. */ if (!user_mode(__frame)) return; if (try_to_freeze()) goto no_signal; if (test_thread_flag(TIF_RESTORE_SIGMASK)) oldset = ¤t->saved_sigmask; else oldset = ¤t->blocked; signr = get_signal_to_deliver(&info, &ka, __frame, NULL); if (signr > 0) { if (handle_signal(signr, &info, &ka, oldset) == 0) { /* a signal was successfully delivered; the saved * sigmask will have been stored in the signal frame, * and will be restored by sigreturn, so we can simply * clear the TIF_RESTORE_SIGMASK flag */ if (test_thread_flag(TIF_RESTORE_SIGMASK)) clear_thread_flag(TIF_RESTORE_SIGMASK); } return; } no_signal: /* Did we come from a system call? */ if (__frame->syscallno >= 0) { /* Restart the system call - no handlers present */ switch (__frame->gr8) { case -ERESTARTNOHAND: case -ERESTARTSYS: case -ERESTARTNOINTR: __frame->gr8 = __frame->orig_gr8; __frame->pc -= 4; break; case -ERESTART_RESTARTBLOCK: __frame->gr8 = __NR_restart_syscall; __frame->pc -= 4; break; } } /* if there's no signal to deliver, we just put the saved sigmask * back */ if (test_thread_flag(TIF_RESTORE_SIGMASK)) { clear_thread_flag(TIF_RESTORE_SIGMASK); sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); } } /* end do_signal() */ /*****************************************************************************/ /* * notification of userspace execution resumption * - triggered by the TIF_WORK_MASK flags */ asmlinkage void do_notify_resume(__u32 thread_info_flags) { /* pending single-step? */ if (thread_info_flags & _TIF_SINGLESTEP) clear_thread_flag(TIF_SINGLESTEP); /* deal with pending signal delivery */ if (thread_info_flags & (_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK)) do_signal(); } /* end do_notify_resume() */