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