arch/tile/kernel/signal.c - maze/linux - Git at Google

 /*
  * Copyright (C) 1991, 1992  Linus Torvalds
  * Copyright 2010 Tilera Corporation. 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
  *   as published by the Free Software Foundation, version 2.
  *
  *   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, GOOD TITLE or
  *   NON INFRINGEMENT.  See the GNU General Public License for
  *   more details.
  */

 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
 #include <linux/smp_lock.h>
 #include <linux/kernel.h>
 #include <linux/signal.h>
 #include <linux/errno.h>
 #include <linux/wait.h>
 #include <linux/unistd.h>
 #include <linux/stddef.h>
 #include <linux/personality.h>
 #include <linux/suspend.h>
 #include <linux/ptrace.h>
 #include <linux/elf.h>
 #include <linux/compat.h>
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
 #include <asm/processor.h>
 #include <asm/ucontext.h>
 #include <asm/sigframe.h>
 #include <asm/syscalls.h>
 #include <arch/interrupts.h>

 #define DEBUG_SIG 0

 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))


 long _sys_sigaltstack(const stack_t __user *uss,
 		      stack_t __user *uoss, struct pt_regs *regs)
 {
 	return do_sigaltstack(uss, uoss, regs->sp);
 }


 /*
  * Do a signal return; undo the signal stack.
  */

 int restore_sigcontext(struct pt_regs *regs,
 		       struct sigcontext __user *sc, long *pr0)
 {
 	int err = 0;
 	int i;

 	/* Always make any pending restarted system calls return -EINTR */
 	current_thread_info()->restart_block.fn = do_no_restart_syscall;

 	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
 		err |= __get_user(((long *)regs)[i],
 				  &((long __user *)(&sc->regs))[i]);

 	regs->faultnum = INT_SWINT_1_SIGRETURN;

 	err |= __get_user(*pr0, &sc->regs.regs[0]);
 	return err;
 }

 /* sigreturn() returns long since it restores r0 in the interrupted code. */
 long _sys_rt_sigreturn(struct pt_regs *regs)
 {
 	struct rt_sigframe __user *frame =
 		(struct rt_sigframe __user *)(regs->sp);
 	sigset_t set;
 	long r0;

 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
 		goto badframe;
 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 		goto badframe;

 	sigdelsetmask(&set, ~_BLOCKABLE);
 	spin_lock_irq(&current->sighand->siglock);
 	current->blocked = set;
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);

 	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
 		goto badframe;

 	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
 		goto badframe;

 	return r0;

 badframe:
 	force_sig(SIGSEGV, current);
 	return 0;
 }

 /*
  * Set up a signal frame.
  */

 int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs)
 {
 	int i, err = 0;

 	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
 		err |= __put_user(((long *)regs)[i],
 				  &((long __user *)(&sc->regs))[i]);

 	return err;
 }

 /*
  * Determine which stack to use..
  */
 static inline void __user *get_sigframe(struct k_sigaction *ka,
 					struct pt_regs *regs,
 					size_t frame_size)
 {
 	unsigned long sp;

 	/* Default to using normal stack */
 	sp = regs->sp;

 	/*
 	 * If we are on the alternate signal stack and would overflow
 	 * it, don't.  Return an always-bogus address instead so we
 	 * will die with SIGSEGV.
 	 */
 	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
 		return (void __user __force *)-1UL;

 	/* This is the X/Open sanctioned signal stack switching.  */
 	if (ka->sa.sa_flags & SA_ONSTACK) {
 		if (sas_ss_flags(sp) == 0)
 			sp = current->sas_ss_sp + current->sas_ss_size;
 	}

 	sp -= frame_size;
 	/*
 	 * Align the stack pointer according to the TILE ABI,
 	 * i.e. so that on function entry (sp & 15) == 0.
 	 */
 	sp &= -16UL;
 	return (void __user *) sp;
 }

 static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 			   sigset_t *set, struct pt_regs *regs)
 {
 	unsigned long restorer;
 	struct rt_sigframe __user *frame;
 	int err = 0;
 	int usig;

 	frame = get_sigframe(ka, regs, sizeof(*frame));

 	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
 		goto give_sigsegv;

 	usig = current_thread_info()->exec_domain
 		&& current_thread_info()->exec_domain->signal_invmap
 		&& sig < 32
 		? current_thread_info()->exec_domain->signal_invmap[sig]
 		: sig;

 	/* Always write at least the signal number for the stack backtracer. */
 	if (ka->sa.sa_flags & SA_SIGINFO) {
 		/* At sigreturn time, restore the callee-save registers too. */
 		err |= copy_siginfo_to_user(&frame->info, info);
 		regs->flags |= PT_FLAGS_RESTORE_REGS;
 	} else {
 		err |= __put_user(info->si_signo, &frame->info.si_signo);
 	}

 	/* Create the ucontext.  */
 	err |= __clear_user(&frame->save_area, sizeof(frame->save_area));
 	err |= __put_user(0, &frame->uc.uc_flags);
 	err |= __put_user(NULL, &frame->uc.uc_link);
 	err |= __put_user((void __user *)(current->sas_ss_sp),
 			  &frame->uc.uc_stack.ss_sp);
 	err |= __put_user(sas_ss_flags(regs->sp),
 			  &frame->uc.uc_stack.ss_flags);
 	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
 	err |= setup_sigcontext(&frame->uc.uc_mcontext, regs);
 	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 	if (err)
 		goto give_sigsegv;

 	restorer = VDSO_BASE;
 	if (ka->sa.sa_flags & SA_RESTORER)
 		restorer = (unsigned long) ka->sa.sa_restorer;

 	/*
 	 * Set up registers for signal handler.
 	 * Registers that we don't modify keep the value they had from
 	 * user-space at the time we took the signal.
 	 */
 	regs->pc = (unsigned long) ka->sa.sa_handler;
 	regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
 	regs->sp = (unsigned long) frame;
 	regs->lr = restorer;
 	regs->regs[0] = (unsigned long) usig;

 	if (ka->sa.sa_flags & SA_SIGINFO) {
 		/* Need extra arguments, so mark to restore caller-saves. */
 		regs->regs[1] = (unsigned long) &frame->info;
 		regs->regs[2] = (unsigned long) &frame->uc;
 		regs->flags |= PT_FLAGS_CALLER_SAVES;
 	}

 	/*
 	 * Notify any tracer that was single-stepping it.
 	 * The tracer may want to single-step inside the
 	 * handler too.
 	 */
 	if (test_thread_flag(TIF_SINGLESTEP))
 		ptrace_notify(SIGTRAP);

 	return 0;

 give_sigsegv:
 	force_sigsegv(sig, current);
 	return -EFAULT;
 }

 /*
  * OK, we're invoking a handler
  */

 static int handle_signal(unsigned long sig, siginfo_t *info,
 			 struct k_sigaction *ka, sigset_t *oldset,
 			 struct pt_regs *regs)
 {
 	int ret;


 	/* Are we from a system call? */
 	if (regs->faultnum == INT_SWINT_1) {
 		/* If so, check system call restarting.. */
 		switch (regs->regs[0]) {
 		case -ERESTART_RESTARTBLOCK:
 		case -ERESTARTNOHAND:
 			regs->regs[0] = -EINTR;
 			break;

 		case -ERESTARTSYS:
 			if (!(ka->sa.sa_flags & SA_RESTART)) {
 				regs->regs[0] = -EINTR;
 				break;
 			}
 			/* fallthrough */
 		case -ERESTARTNOINTR:
 			/* Reload caller-saves to restore r0..r5 and r10. */
 			regs->flags |= PT_FLAGS_CALLER_SAVES;
 			regs->regs[0] = regs->orig_r0;
 			regs->pc -= 8;
 		}
 	}

 	/* Set up the stack frame */
 #ifdef CONFIG_COMPAT
 	if (is_compat_task())
 		ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
 	else
 #endif
 		ret = setup_rt_frame(sig, ka, info, oldset, regs);
 	if (ret == 0) {
 		/* This code is only called from system calls or from
 		 * the work_pending path in the return-to-user code, and
 		 * either way we can re-enable interrupts unconditionally.
 		 */
 		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 ret;
 }

 /*
  * Note that 'init' is a special process: it doesn't get signals it doesn't
  * want to handle. Thus you cannot kill init even with a SIGKILL even by
  * mistake.
  */
 void do_signal(struct pt_regs *regs)
 {
 	siginfo_t info;
 	int signr;
 	struct k_sigaction ka;
 	sigset_t *oldset;

 	/*
 	 * i386 will check if we're coming from kernel mode and bail out
 	 * here.  In my experience this just turns weird crashes into
 	 * weird spin-hangs.  But if we find a case where this seems
 	 * helpful, we can reinstate the check on "!user_mode(regs)".
 	 */

 	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
 		oldset = &current->saved_sigmask;
 	else
 		oldset = &current->blocked;

 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 	if (signr > 0) {
 		/* Whee! Actually deliver the signal.  */
 		if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
 			/*
 			 * A signal was successfully delivered; the saved
 			 * sigmask will have been stored in the signal frame,
 			 * and will be restored by sigreturn, so we can simply
 			 * clear the TS_RESTORE_SIGMASK flag.
 			 */
 			current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 		}

 		return;
 	}

 	/* Did we come from a system call? */
 	if (regs->faultnum == INT_SWINT_1) {
 		/* Restart the system call - no handlers present */
 		switch (regs->regs[0]) {
 		case -ERESTARTNOHAND:
 		case -ERESTARTSYS:
 		case -ERESTARTNOINTR:
 			regs->flags |= PT_FLAGS_CALLER_SAVES;
 			regs->regs[0] = regs->orig_r0;
 			regs->pc -= 8;
 			break;

 		case -ERESTART_RESTARTBLOCK:
 			regs->flags |= PT_FLAGS_CALLER_SAVES;
 			regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
 			regs->pc -= 8;
 			break;
 		}
 	}

 	/* If there's no signal to deliver, just put the saved sigmask back. */
 	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
 		current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
 		sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
 	}
 }
	/*
	* Copyright (C) 1991, 1992 Linus Torvalds
	* Copyright 2010 Tilera Corporation. 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
	* as published by the Free Software Foundation, version 2.
	*
	* 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, GOOD TITLE or
	* NON INFRINGEMENT. See the GNU General Public License for
	* more details.
	*/

	#include <linux/sched.h>
	#include <linux/mm.h>
	#include <linux/smp.h>
	#include <linux/smp_lock.h>
	#include <linux/kernel.h>
	#include <linux/signal.h>
	#include <linux/errno.h>
	#include <linux/wait.h>
	#include <linux/unistd.h>
	#include <linux/stddef.h>
	#include <linux/personality.h>
	#include <linux/suspend.h>
	#include <linux/ptrace.h>
	#include <linux/elf.h>
	#include <linux/compat.h>
	#include <linux/syscalls.h>
	#include <linux/uaccess.h>
	#include <asm/processor.h>
	#include <asm/ucontext.h>
	#include <asm/sigframe.h>
	#include <asm/syscalls.h>
	#include <arch/interrupts.h>

	#define DEBUG_SIG 0

	#define _BLOCKABLE (~(sigmask(SIGKILL) \| sigmask(SIGSTOP)))


	long _sys_sigaltstack(const stack_t __user *uss,
	stack_t __user uoss, struct pt_regs regs)
	{
	return do_sigaltstack(uss, uoss, regs->sp);
	}


	/*
	* Do a signal return; undo the signal stack.
	*/

	int restore_sigcontext(struct pt_regs *regs,
	struct sigcontext __user sc, long pr0)
	{
	int err = 0;
	int i;

	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
	err \|= __get_user(((long *)regs)[i],
	&((long __user *)(&sc->regs))[i]);

	regs->faultnum = INT_SWINT_1_SIGRETURN;

	err \|= __get_user(*pr0, &sc->regs.regs[0]);
	return err;
	}

	/* sigreturn() returns long since it restores r0 in the interrupted code. */
	long _sys_rt_sigreturn(struct pt_regs *regs)
	{
	struct rt_sigframe __user *frame =
	(struct rt_sigframe __user *)(regs->sp);
	sigset_t set;
	long r0;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
	goto badframe;
	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
	goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
	goto badframe;

	if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->sp) == -EFAULT)
	goto badframe;

	return r0;

	badframe:
	force_sig(SIGSEGV, current);
	return 0;
	}

	/*
	* Set up a signal frame.
	*/

	int setup_sigcontext(struct sigcontext __user sc, struct pt_regs regs)
	{
	int i, err = 0;

	for (i = 0; i < sizeof(struct pt_regs)/sizeof(long); ++i)
	err \|= __put_user(((long *)regs)[i],
	&((long __user *)(&sc->regs))[i]);

	return err;
	}

	/*
	* Determine which stack to use..
	*/
	static inline void __user get_sigframe(struct k_sigaction ka,
	struct pt_regs *regs,
	size_t frame_size)
	{
	unsigned long sp;

	/* Default to using normal stack */
	sp = regs->sp;

	/*
	* If we are on the alternate signal stack and would overflow
	* it, don't. Return an always-bogus address instead so we
	* will die with SIGSEGV.
	*/
	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - frame_size)))
	return (void __user __force *)-1UL;

	/* This is the X/Open sanctioned signal stack switching. */
	if (ka->sa.sa_flags & SA_ONSTACK) {
	if (sas_ss_flags(sp) == 0)
	sp = current->sas_ss_sp + current->sas_ss_size;
	}

	sp -= frame_size;
	/*
	* Align the stack pointer according to the TILE ABI,
	* i.e. so that on function entry (sp & 15) == 0.
	*/
	sp &= -16UL;
	return (void __user *) sp;
	}

	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
	sigset_t set, struct pt_regs regs)
	{
	unsigned long restorer;
	struct rt_sigframe __user *frame;
	int err = 0;
	int usig;

	frame = get_sigframe(ka, regs, sizeof(*frame));

	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
	goto give_sigsegv;

	usig = current_thread_info()->exec_domain
	&& current_thread_info()->exec_domain->signal_invmap
	&& sig < 32
	? current_thread_info()->exec_domain->signal_invmap[sig]
	: sig;

	/* Always write at least the signal number for the stack backtracer. */
	if (ka->sa.sa_flags & SA_SIGINFO) {
	/* At sigreturn time, restore the callee-save registers too. */
	err \|= copy_siginfo_to_user(&frame->info, info);
	regs->flags \|= PT_FLAGS_RESTORE_REGS;
	} else {
	err \|= __put_user(info->si_signo, &frame->info.si_signo);
	}

	/* Create the ucontext. */
	err \|= __clear_user(&frame->save_area, sizeof(frame->save_area));
	err \|= __put_user(0, &frame->uc.uc_flags);
	err \|= __put_user(NULL, &frame->uc.uc_link);
	err \|= __put_user((void __user *)(current->sas_ss_sp),
	&frame->uc.uc_stack.ss_sp);
	err \|= __put_user(sas_ss_flags(regs->sp),
	&frame->uc.uc_stack.ss_flags);
	err \|= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
	err \|= setup_sigcontext(&frame->uc.uc_mcontext, regs);
	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
	goto give_sigsegv;

	restorer = VDSO_BASE;
	if (ka->sa.sa_flags & SA_RESTORER)
	restorer = (unsigned long) ka->sa.sa_restorer;

	/*
	* Set up registers for signal handler.
	* Registers that we don't modify keep the value they had from
	* user-space at the time we took the signal.
	*/
	regs->pc = (unsigned long) ka->sa.sa_handler;
	regs->ex1 = PL_ICS_EX1(USER_PL, 1); /* set crit sec in handler */
	regs->sp = (unsigned long) frame;
	regs->lr = restorer;
	regs->regs[0] = (unsigned long) usig;

	if (ka->sa.sa_flags & SA_SIGINFO) {
	/* Need extra arguments, so mark to restore caller-saves. */
	regs->regs[1] = (unsigned long) &frame->info;
	regs->regs[2] = (unsigned long) &frame->uc;
	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	}

	/*
	* Notify any tracer that was single-stepping it.
	* The tracer may want to single-step inside the
	* handler too.
	*/
	if (test_thread_flag(TIF_SINGLESTEP))
	ptrace_notify(SIGTRAP);

	return 0;

	give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
	}

	/*
	* OK, we're invoking a handler
	*/

	static int handle_signal(unsigned long sig, siginfo_t *info,
	struct k_sigaction ka, sigset_t oldset,
	struct pt_regs *regs)
	{
	int ret;


	/* Are we from a system call? */
	if (regs->faultnum == INT_SWINT_1) {
	/* If so, check system call restarting.. */
	switch (regs->regs[0]) {
	case -ERESTART_RESTARTBLOCK:
	case -ERESTARTNOHAND:
	regs->regs[0] = -EINTR;
	break;

	case -ERESTARTSYS:
	if (!(ka->sa.sa_flags & SA_RESTART)) {
	regs->regs[0] = -EINTR;
	break;
	}
	/* fallthrough */
	case -ERESTARTNOINTR:
	/* Reload caller-saves to restore r0..r5 and r10. */
	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	regs->regs[0] = regs->orig_r0;
	regs->pc -= 8;
	}
	}

	/* Set up the stack frame */
	#ifdef CONFIG_COMPAT
	if (is_compat_task())
	ret = compat_setup_rt_frame(sig, ka, info, oldset, regs);
	else
	#endif
	ret = setup_rt_frame(sig, ka, info, oldset, regs);
	if (ret == 0) {
	/* This code is only called from system calls or from
	* the work_pending path in the return-to-user code, and
	* either way we can re-enable interrupts unconditionally.
	*/
	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 ret;
	}

	/*
	* Note that 'init' is a special process: it doesn't get signals it doesn't
	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	* mistake.
	*/
	void do_signal(struct pt_regs *regs)
	{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
	sigset_t *oldset;

	/*
	* i386 will check if we're coming from kernel mode and bail out
	* here. In my experience this just turns weird crashes into
	* weird spin-hangs. But if we find a case where this seems
	* helpful, we can reinstate the check on "!user_mode(regs)".
	*/

	if (current_thread_info()->status & TS_RESTORE_SIGMASK)
	oldset = &current->saved_sigmask;
	else
	oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
	if (signr > 0) {
	/* Whee! Actually deliver the signal. */
	if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
	/*
	* A signal was successfully delivered; the saved
	* sigmask will have been stored in the signal frame,
	* and will be restored by sigreturn, so we can simply
	* clear the TS_RESTORE_SIGMASK flag.
	*/
	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
	}

	return;
	}

	/* Did we come from a system call? */
	if (regs->faultnum == INT_SWINT_1) {
	/* Restart the system call - no handlers present */
	switch (regs->regs[0]) {
	case -ERESTARTNOHAND:
	case -ERESTARTSYS:
	case -ERESTARTNOINTR:
	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	regs->regs[0] = regs->orig_r0;
	regs->pc -= 8;
	break;

	case -ERESTART_RESTARTBLOCK:
	regs->flags \|= PT_FLAGS_CALLER_SAVES;
	regs->regs[TREG_SYSCALL_NR] = __NR_restart_syscall;
	regs->pc -= 8;
	break;
	}
	}

	/* If there's no signal to deliver, just put the saved sigmask back. */
	if (current_thread_info()->status & TS_RESTORE_SIGMASK) {
	current_thread_info()->status &= ~TS_RESTORE_SIGMASK;
	sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
	}
	}