/* * Signal support for Hexagon processor * * Copyright (c) 2010-2012, The Linux Foundation. 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 <linux/linkage.h> #include <linux/syscalls.h> #include <linux/tracehook.h> #include <asm/registers.h> #include <asm/thread_info.h> #include <asm/unistd.h> #include <asm/uaccess.h> #include <asm/ucontext.h> #include <asm/cacheflush.h> #include <asm/signal.h> #include <asm/vdso.h> struct rt_sigframe { unsigned long tramp[2]; struct siginfo info; struct ucontext uc; }; static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size) { unsigned long sp = sigsp(regs->r29, ksig); 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); #if CONFIG_HEXAGON_ARCH_VERSION >= 4 err |= __put_user(regs->cs0, &sc->sc_regs.cs0); err |= __put_user(regs->cs1, &sc->sc_regs.cs1); #endif 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); #if CONFIG_HEXAGON_ARCH_VERSION >= 4 err |= __get_user(regs->cs0, &sc->sc_regs.cs0); err |= __get_user(regs->cs1, &sc->sc_regs.cs1); #endif 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(struct ksignal *ksig, 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(ksig, regs, sizeof(struct rt_sigframe)); if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe))) return -EFAULT; if (copy_siginfo_to_user(&frame->info, &ksig->info)) return -EFAULT; /* 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)); err |= __save_altstack(&frame->uc.uc_stack, user_stack_pointer(regs)); if (err) return -EFAULT; /* Load r0/r1 pair with signumber/siginfo pointer... */ regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) | (unsigned long long)ksig->sig; 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)ksig->ka.sa.sa_handler); return 0; } /* * Setup invocation of signal handler */ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) { int ret; /* * 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 (!(ksig->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. */ ret = setup_rt_frame(ksig, sigmask_to_save(), regs); signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP)); } /* * Called from return-from-event code. */ void do_signal(struct pt_regs *regs) { struct ksignal ksig; if (!user_mode(regs)) return; if (get_signal(&ksig)) { handle_signal(&ksig, regs); return; } /* * No (more) signals; 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(); } /* * Architecture-specific wrappers for signal-related system calls */ asmlinkage int sys_rt_sigreturn(void) { struct pt_regs *regs = current_pt_regs(); struct rt_sigframe __user *frame; sigset_t blocked; /* Always make any pending restarted system calls return -EINTR */ current->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; regs->syscall_nr = -1; if (restore_altstack(&frame->uc.uc_stack)) goto badframe; return regs->r00; badframe: force_sig(SIGSEGV, current); return 0; }