Hexagon: Add signal functions

/*

 * 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.

 */

#ifndef _ASM_SIGCONTEXT_H

#define _ASM_SIGCONTEXT_H

#include <asm/user.h>

/*

 * Signal context structure - contains all info to do with the state

 * before the signal handler was invoked.  Note: only add new entries

 * to the end of the structure.

 */

struct sigcontext {

	struct user_regs_struct sc_regs;

} __aligned(8);

#endif

/*

 * 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.

 */

#ifndef _ASM_SIGNAL_H

#define _ASM_SIGNAL_H

extern unsigned long __rt_sigtramp_template[2];

#include <asm-generic/signal.h>

#endif

/*

 * vDSO implementation for Hexagon

 *

 * Copyright (c) 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.

 */

#ifndef __ASM_VDSO_H

#define __ASM_VDSO_H

#include <linux/types.h>

struct hexagon_vdso {

	u32 rt_signal_trampoline[2];

};

#endif /* __ASM_VDSO_H */

/*

 * 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, &regs->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(&regs->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(&current->sighand->siglock);

	sigorsets(&current->blocked, &current->blocked, &ka->sa.sa_mask);

	if (!(ka->sa.sa_flags & SA_NODEFER))

		sigaddset(&current->blocked, sig);

	recalc_sigpending();

	spin_unlock_irq(&current->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 = &current->saved_sigmask;

		else

			oldset = &current->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, &current->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(&current->sighand->siglock);

	current->blocked = blocked;

	recalc_sigpending();

	spin_unlock_irq(&current->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;

}

/*

 * 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.

 */

/*

 * Trampoline sequences to be copied onto user stack.

 * This consumes a little more space than hand-assembling

 * immediate constants for use in C, but is more portable

 * to future tweaks to the Hexagon instruction set.

 */

#include <asm/unistd.h>

/*  Sig trampolines - call sys_sigreturn or sys_rt_sigreturn as appropriate */

/*  plain sigreturn is gone.  */

	.globl __rt_sigtramp_template

__rt_sigtramp_template:

	r6 = #__NR_rt_sigreturn;

	trap0(#1);