/* * Signal support for Hexagon processor * * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and * only version 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301, USA. */ #include #include #include #include #include #include #include #include #include #include #include #include struct rt_sigframe { unsigned long tramp[2]; struct siginfo info; struct ucontext uc; }; static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size) { unsigned long sp = regs->r29; /* Switch to signal stack if appropriate */ if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0)) sp = current->sas_ss_sp + current->sas_ss_size; return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1)); } static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { unsigned long tmp; int err = 0; err |= copy_to_user(&sc->sc_regs.r0, ®s->r00, 32*sizeof(unsigned long)); err |= __put_user(regs->sa0, &sc->sc_regs.sa0); err |= __put_user(regs->lc0, &sc->sc_regs.lc0); err |= __put_user(regs->sa1, &sc->sc_regs.sa1); err |= __put_user(regs->lc1, &sc->sc_regs.lc1); err |= __put_user(regs->m0, &sc->sc_regs.m0); err |= __put_user(regs->m1, &sc->sc_regs.m1); err |= __put_user(regs->usr, &sc->sc_regs.usr); err |= __put_user(regs->preds, &sc->sc_regs.p3_0); err |= __put_user(regs->gp, &sc->sc_regs.gp); err |= __put_user(regs->ugp, &sc->sc_regs.ugp); tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc); tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause); tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva); return err; } static int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { unsigned long tmp; int err = 0; err |= copy_from_user(®s->r00, &sc->sc_regs.r0, 32 * sizeof(unsigned long)); err |= __get_user(regs->sa0, &sc->sc_regs.sa0); err |= __get_user(regs->lc0, &sc->sc_regs.lc0); err |= __get_user(regs->sa1, &sc->sc_regs.sa1); err |= __get_user(regs->lc1, &sc->sc_regs.lc1); err |= __get_user(regs->m0, &sc->sc_regs.m0); err |= __get_user(regs->m1, &sc->sc_regs.m1); err |= __get_user(regs->usr, &sc->sc_regs.usr); err |= __get_user(regs->preds, &sc->sc_regs.p3_0); err |= __get_user(regs->gp, &sc->sc_regs.gp); err |= __get_user(regs->ugp, &sc->sc_regs.ugp); err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp); return err; } /* * Setup signal stack frame with siginfo structure */ static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs *regs) { int err = 0; struct rt_sigframe __user *frame; struct hexagon_vdso *vdso = current->mm->context.vdso; frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe)); if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe))) goto sigsegv; if (copy_siginfo_to_user(&frame->info, info)) goto sigsegv; /* The on-stack signal trampoline is no longer executed; * however, the libgcc signal frame unwinding code checks for * the presence of these two numeric magic values. */ err |= __put_user(0x7800d166, &frame->tramp[0]); err |= __put_user(0x5400c004, &frame->tramp[1]); err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); if (err) goto sigsegv; /* Load r0/r1 pair with signumber/siginfo pointer... */ regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) | (unsigned long long)signr; regs->r02 = (unsigned long) &frame->uc; regs->r31 = (unsigned long) vdso->rt_signal_trampoline; pt_psp(regs) = (unsigned long) frame; pt_set_elr(regs, (unsigned long)ka->sa.sa_handler); return 0; sigsegv: force_sigsegv(signr, current); return -EFAULT; } /* * Setup invocation of signal handler */ static void handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka, struct pt_regs *regs) { /* * If we're handling a signal that aborted a system call, * set up the error return value before adding the signal * frame to the stack. */ if (regs->syscall_nr >= 0) { switch (regs->r00) { case -ERESTART_RESTARTBLOCK: case -ERESTARTNOHAND: regs->r00 = -EINTR; break; case -ERESTARTSYS: if (!(ka->sa.sa_flags & SA_RESTART)) { regs->r00 = -EINTR; break; } /* Fall through */ case -ERESTARTNOINTR: regs->r06 = regs->syscall_nr; pt_set_elr(regs, pt_elr(regs) - 4); regs->r00 = regs->restart_r0; break; default: break; } } /* * Set up the stack frame; not doing the SA_SIGINFO thing. We * only set up the rt_frame flavor. */ /* If there was an error on setup, no signal was delivered. */ if (setup_rt_frame(sig, ka, info, sigmask_to_save(), regs) < 0) return; signal_delivered(sig, info, ka, regs, test_thread_flag(TIF_SINGLESTEP)); } /* * Called from return-from-event code. */ static void do_signal(struct pt_regs *regs) { struct k_sigaction sigact; siginfo_t info; int signo; if (!user_mode(regs)) return; signo = get_signal_to_deliver(&info, &sigact, regs, NULL); if (signo > 0) { handle_signal(signo, &info, &sigact, regs); return; } /* * If we came from a system call, handle the restart. */ if (regs->syscall_nr >= 0) { switch (regs->r00) { case -ERESTARTNOHAND: case -ERESTARTSYS: case -ERESTARTNOINTR: regs->r06 = regs->syscall_nr; break; case -ERESTART_RESTARTBLOCK: regs->r06 = __NR_restart_syscall; break; default: goto no_restart; } pt_set_elr(regs, pt_elr(regs) - 4); regs->r00 = regs->restart_r0; } no_restart: /* If there's no signal to deliver, put the saved sigmask back */ restore_saved_sigmask(); } void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) { 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(regs); } } /* * Architecture-specific wrappers for signal-related system calls */ asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss) { struct pt_regs *regs = current_thread_info()->regs; return do_sigaltstack(uss, uoss, regs->r29); } asmlinkage int sys_rt_sigreturn(void) { struct pt_regs *regs = current_thread_info()->regs; struct rt_sigframe __user *frame; sigset_t blocked; /* Always make any pending restarted system calls return -EINTR */ current_thread_info()->restart_block.fn = do_no_restart_syscall; frame = (struct rt_sigframe __user *)pt_psp(regs); if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked))) goto badframe; set_current_blocked(&blocked); if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) goto badframe; /* Restore the user's stack as well */ pt_psp(regs) = regs->r29; /* * Leave a trace in the stack frame that this was a sigreturn. * If the system call is to replay, we've already restored the * number in the GPR slot and it will be regenerated on the * new system call trap entry. Note that if restore_sigcontext() * did something other than a bulk copy of the pt_regs struct, * we could avoid this assignment by simply not overwriting * regs->syscall_nr. */ regs->syscall_nr = __NR_rt_sigreturn; /* * If we were meticulous, we'd only call this if we knew that * we were actually going to use an alternate stack, and we'd * consider any error to be fatal. What we do here, in common * with many other architectures, is call it blindly and only * consider the -EFAULT return case to be proof of a problem. */ if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT) goto badframe; return 0; badframe: force_sig(SIGSEGV, current); return 0; }