diff options
Diffstat (limited to 'arch/hexagon/kernel/signal.c')
| -rw-r--r-- | arch/hexagon/kernel/signal.c | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/arch/hexagon/kernel/signal.c b/arch/hexagon/kernel/signal.c new file mode 100644 index 0000000..b45be31 --- /dev/null +++ b/arch/hexagon/kernel/signal.c @@ -0,0 +1,345 @@ +/* + * 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 <linux/linkage.h> +#include <linux/syscalls.h> +#include <linux/freezer.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> + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +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 int handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka, + sigset_t *oldset, struct pt_regs *regs) +{ + int rc; + + /* + * 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. + */ + rc = setup_rt_frame(sig, ka, info, oldset, regs); + + /* If there was an error on setup, no signal was delivered. */ + if (rc) + return rc; + + 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 0; +} + +/* + * 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; + + if (try_to_freeze()) + goto no_signal; + + signo = get_signal_to_deliver(&info, &sigact, regs, NULL); + + if (signo > 0) { + sigset_t *oldset; + + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + oldset = ¤t->saved_sigmask; + else + oldset = ¤t->blocked; + + if (handle_signal(signo, &info, &sigact, oldset, regs) == 0) { + /* + * Successful delivery case. The saved sigmask is + * stored in the signal frame, and will be restored + * by sigreturn. We can clear the TIF flag. + */ + clear_thread_flag(TIF_RESTORE_SIGMASK); + + tracehook_signal_handler(signo, &info, &sigact, regs, + test_thread_flag(TIF_SINGLESTEP)); + } + return; + } + +no_signal: + /* + * 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 */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) { + clear_thread_flag(TIF_RESTORE_SIGMASK); + sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); + } +} + +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); + if (current->replacement_session_keyring) + key_replace_session_keyring(); + } +} + +/* + * 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; + + 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; + + sigdelsetmask(&blocked, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + current->blocked = blocked; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + 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; +} |