/* MN10300 Signal handling * * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public Licence * as published by the Free Software Foundation; either version * 2 of the Licence, 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/stddef.h> #include <linux/tty.h> #include <linux/personality.h> #include <linux/suspend.h> #include <linux/tracehook.h> #include <asm/cacheflush.h> #include <asm/ucontext.h> #include <linux/uaccess.h> #include <asm/fpu.h> #include "sigframe.h" #define DEBUG_SIG 0 /* * do a signal return; undo the signal stack. */ static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, long *_d0) { unsigned int err = 0; /* Always make any pending restarted system calls return -EINTR */ current->restart_block.fn = do_no_restart_syscall; if (is_using_fpu(current)) fpu_kill_state(current); #define COPY(x) err |= __get_user(regs->x, &sc->x) COPY(d1); COPY(d2); COPY(d3); COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(e0); COPY(e1); COPY(e2); COPY(e3); COPY(e4); COPY(e5); COPY(e6); COPY(e7); COPY(lar); COPY(lir); COPY(mdr); COPY(mdrq); COPY(mcvf); COPY(mcrl); COPY(mcrh); COPY(sp); COPY(pc); #undef COPY { unsigned int tmpflags; #ifndef CONFIG_MN10300_USING_JTAG #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \ EPSW_T | EPSW_nAR) #else #define USER_EPSW (EPSW_FLAG_Z | EPSW_FLAG_N | EPSW_FLAG_C | EPSW_FLAG_V | \ EPSW_nAR) #endif err |= __get_user(tmpflags, &sc->epsw); regs->epsw = (regs->epsw & ~USER_EPSW) | (tmpflags & USER_EPSW); regs->orig_d0 = -1; /* disable syscall checks */ } { struct fpucontext *buf; err |= __get_user(buf, &sc->fpucontext); if (buf) { if (!access_ok(VERIFY_READ, buf, sizeof(*buf))) goto badframe; err |= fpu_restore_sigcontext(buf); } } err |= __get_user(*_d0, &sc->d0); return err; badframe: return 1; } /* * standard signal return syscall */ asmlinkage long sys_sigreturn(void) { struct sigframe __user *frame; sigset_t set; long d0; frame = (struct sigframe __user *) current_frame()->sp; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__get_user(set.sig[0], &frame->sc.oldmask)) goto badframe; if (_NSIG_WORDS > 1 && __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask))) goto badframe; set_current_blocked(&set); if (restore_sigcontext(current_frame(), &frame->sc, &d0)) goto badframe; return d0; badframe: force_sig(SIGSEGV, current); return 0; } /* * realtime signal return syscall */ asmlinkage long sys_rt_sigreturn(void) { struct rt_sigframe __user *frame; sigset_t set; long d0; frame = (struct rt_sigframe __user *) current_frame()->sp; if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) goto badframe; set_current_blocked(&set); if (restore_sigcontext(current_frame(), &frame->uc.uc_mcontext, &d0)) goto badframe; if (restore_altstack(&frame->uc.uc_stack)) goto badframe; return d0; badframe: force_sig(SIGSEGV, current); return 0; } /* * store the userspace context into a signal frame */ static int setup_sigcontext(struct sigcontext __user *sc, struct fpucontext *fpuctx, struct pt_regs *regs, unsigned long mask) { int tmp, err = 0; #define COPY(x) err |= __put_user(regs->x, &sc->x) COPY(d0); COPY(d1); COPY(d2); COPY(d3); COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(e0); COPY(e1); COPY(e2); COPY(e3); COPY(e4); COPY(e5); COPY(e6); COPY(e7); COPY(lar); COPY(lir); COPY(mdr); COPY(mdrq); COPY(mcvf); COPY(mcrl); COPY(mcrh); COPY(sp); COPY(epsw); COPY(pc); #undef COPY tmp = fpu_setup_sigcontext(fpuctx); if (tmp < 0) err = 1; else err |= __put_user(tmp ? fpuctx : NULL, &sc->fpucontext); /* non-iBCS2 extensions.. */ err |= __put_user(mask, &sc->oldmask); return err; } /* * determine which stack to use.. */ static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size) { unsigned long sp = sigsp(regs->sp, ksig); return (void __user *) ((sp - frame_size) & ~7UL); } /* * set up a normal signal frame */ static int setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) { struct sigframe __user *frame; int sig = ksig->sig; frame = get_sigframe(ksig, regs, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) return -EFAULT; if (__put_user(sig, &frame->sig) < 0 || __put_user(&frame->sc, &frame->psc) < 0) return -EFAULT; if (setup_sigcontext(&frame->sc, &frame->fpuctx, regs, set->sig[0])) return -EFAULT; if (_NSIG_WORDS > 1) { if (__copy_to_user(frame->extramask, &set->sig[1], sizeof(frame->extramask))) return -EFAULT; } /* set up to return from userspace. If provided, use a stub already in * userspace */ if (ksig->ka.sa.sa_flags & SA_RESTORER) { if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode)) return -EFAULT; } else { if (__put_user((void (*)(void))frame->retcode, &frame->pretcode)) return -EFAULT; /* this is mov $,d0; syscall 0 */ if (__put_user(0x2c, (char *)(frame->retcode + 0)) || __put_user(__NR_sigreturn, (char *)(frame->retcode + 1)) || __put_user(0x00, (char *)(frame->retcode + 2)) || __put_user(0xf0, (char *)(frame->retcode + 3)) || __put_user(0xe0, (char *)(frame->retcode + 4))) return -EFAULT; flush_icache_range((unsigned long) frame->retcode, (unsigned long) frame->retcode + 5); } /* set up registers for signal handler */ regs->sp = (unsigned long) frame; regs->pc = (unsigned long) ksig->ka.sa.sa_handler; regs->d0 = sig; regs->d1 = (unsigned long) &frame->sc; #if DEBUG_SIG printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n", sig, current->comm, current->pid, frame, regs->pc, frame->pretcode); #endif return 0; } /* * set up a realtime signal frame */ static int setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs) { struct rt_sigframe __user *frame; int sig = ksig->sig; frame = get_sigframe(ksig, regs, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) return -EFAULT; if (__put_user(sig, &frame->sig) || __put_user(&frame->info, &frame->pinfo) || __put_user(&frame->uc, &frame->puc) || copy_siginfo_to_user(&frame->info, &ksig->info)) return -EFAULT; /* create the ucontext. */ if (__put_user(0, &frame->uc.uc_flags) || __put_user(0, &frame->uc.uc_link) || __save_altstack(&frame->uc.uc_stack, regs->sp) || setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpuctx, regs, set->sig[0]) || __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set))) return -EFAULT; /* set up to return from userspace. If provided, use a stub already in * userspace */ if (ksig->ka.sa.sa_flags & SA_RESTORER) { if (__put_user(ksig->ka.sa.sa_restorer, &frame->pretcode)) return -EFAULT; } else { if (__put_user((void(*)(void))frame->retcode, &frame->pretcode) || /* This is mov $,d0; syscall 0 */ __put_user(0x2c, (char *)(frame->retcode + 0)) || __put_user(__NR_rt_sigreturn, (char *)(frame->retcode + 1)) || __put_user(0x00, (char *)(frame->retcode + 2)) || __put_user(0xf0, (char *)(frame->retcode + 3)) || __put_user(0xe0, (char *)(frame->retcode + 4))) return -EFAULT; flush_icache_range((u_long) frame->retcode, (u_long) frame->retcode + 5); } /* Set up registers for signal handler */ regs->sp = (unsigned long) frame; regs->pc = (unsigned long) ksig->ka.sa.sa_handler; regs->d0 = sig; regs->d1 = (long) &frame->info; #if DEBUG_SIG printk(KERN_DEBUG "SIG deliver %d (%s:%d): sp=%p pc=%lx ra=%p\n", sig, current->comm, current->pid, frame, regs->pc, frame->pretcode); #endif return 0; } static inline void stepback(struct pt_regs *regs) { regs->pc -= 2; regs->orig_d0 = -1; } /* * handle the actual delivery of a signal to userspace */ static int handle_signal(struct ksignal *ksig, struct pt_regs *regs) { sigset_t *oldset = sigmask_to_save(); int ret; /* Are we from a system call? */ if (regs->orig_d0 >= 0) { /* If so, check system call restarting.. */ switch (regs->d0) { case -ERESTART_RESTARTBLOCK: case -ERESTARTNOHAND: regs->d0 = -EINTR; break; case -ERESTARTSYS: if (!(ksig->ka.sa.sa_flags & SA_RESTART)) { regs->d0 = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: regs->d0 = regs->orig_d0; stepback(regs); } } /* Set up the stack frame */ if (ksig->ka.sa.sa_flags & SA_SIGINFO) ret = setup_rt_frame(ksig, oldset, regs); else ret = setup_frame(ksig, oldset, regs); signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); return 0; } /* * handle a potential signal */ static void do_signal(struct pt_regs *regs) { struct ksignal ksig; if (get_signal(&ksig)) { handle_signal(&ksig, regs); return; } /* did we come from a system call? */ if (regs->orig_d0 >= 0) { /* restart the system call - no handlers present */ switch (regs->d0) { case -ERESTARTNOHAND: case -ERESTARTSYS: case -ERESTARTNOINTR: regs->d0 = regs->orig_d0; stepback(regs); break; case -ERESTART_RESTARTBLOCK: regs->d0 = __NR_restart_syscall; stepback(regs); break; } } /* if there's no signal to deliver, we just put the saved sigmask * back */ restore_saved_sigmask(); } /* * notification of userspace execution resumption * - triggered by current->work.notify_resume */ asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags) { /* Pending single-step? */ if (thread_info_flags & _TIF_SINGLESTEP) { #ifndef CONFIG_MN10300_USING_JTAG regs->epsw |= EPSW_T; clear_thread_flag(TIF_SINGLESTEP); #else BUG(); /* no h/w single-step if using JTAG unit */ #endif } /* deal with pending signal delivery */ if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); if (thread_info_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(current_frame()); } }