/*
   *  linux/arch/sh/kernel/signal.c
   *
   *  Copyright (C) 1991, 1992  Linus Torvalds
   *
   *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
   *
   *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
   *
   */

  #include <linux/sched.h>
  #include <linux/mm.h>
  #include <linux/smp.h>

  #include <linux/kernel.h>
  #include <linux/signal.h>
  #include <linux/errno.h>
  #include <linux/wait.h>
  #include <linux/ptrace.h>
  #include <linux/unistd.h>
  #include <linux/stddef.h>
  #include <linux/tty.h>

  #include <linux/elf.h>

  #include <linux/personality.h>
  #include <linux/binfmts.h>

  #include <linux/freezer.h>

  #include <linux/io.h>

  #include <linux/tracehook.h>

  #include <asm/system.h>

  #include <asm/ucontext.h>
  #include <asm/uaccess.h>
  #include <asm/pgtable.h>
  #include <asm/cacheflush.h>

  #include <asm/syscalls.h>

  #include <asm/fpu.h>

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

  struct fdpic_func_descriptor {
  	unsigned long	text;
  	unsigned long	GOT;
  };

  /*

   * The following define adds a 64 byte gap between the signal
   * stack frame and previous contents of the stack.  This allows
   * frame unwinding in a function epilogue but only if a frame
   * pointer is used in the function.  This is necessary because
   * current gcc compilers (<4.3) do not generate unwind info on
   * SH for function epilogues.
   */
  #define UNWINDGUARD 64
  
  /*

   * Atomically swap in the new signal mask, and wait for a signal.
   */
  asmlinkage int
  sys_sigsuspend(old_sigset_t mask,
  	       unsigned long r5, unsigned long r6, unsigned long r7,

  	       struct pt_regs __regs)

  {

  	mask &= _BLOCKABLE;
  	spin_lock_irq(&current->sighand->siglock);

  	current->saved_sigmask = current->blocked;

  	siginitset(&current->blocked, mask);
  	recalc_sigpending();
  	spin_unlock_irq(&current->sighand->siglock);

  	current->state = TASK_INTERRUPTIBLE;
  	schedule();

  	set_restore_sigmask();

  	return -ERESTARTNOHAND;

  }

  asmlinkage int

  sys_sigaction(int sig, const struct old_sigaction __user *act,
  	      struct old_sigaction __user *oact)
  {
  	struct k_sigaction new_ka, old_ka;
  	int ret;
  
  	if (act) {
  		old_sigset_t mask;
  		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
  		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
  		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
  			return -EFAULT;
  		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
  		__get_user(mask, &act->sa_mask);
  		siginitset(&new_ka.sa.sa_mask, mask);
  	}
  
  	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
  
  	if (!ret && oact) {
  		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
  		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
  		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
  			return -EFAULT;
  		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
  		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
  	}
  
  	return ret;
  }
  
  asmlinkage int
  sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
  		unsigned long r6, unsigned long r7,

  		struct pt_regs __regs)

  {

  	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
  
  	return do_sigaltstack(uss, uoss, regs->regs[15]);

  }
  
  
  /*
   * Do a signal return; undo the signal stack.
   */
  
  #define MOVW(n)	 (0x9300|((n)-2))	/* Move mem word at PC+n to R3 */

  #if defined(CONFIG_CPU_SH2)

  #define TRAP_NOARG 0xc320		/* Syscall w/no args (NR in R3) */
  #else
  #define TRAP_NOARG 0xc310		/* Syscall w/no args (NR in R3) */
  #endif

  #define OR_R0_R0 0x200b			/* or r0,r0 (insert to avoid hardware bug) */
  
  struct sigframe
  {
  	struct sigcontext sc;
  	unsigned long extramask[_NSIG_WORDS-1];
  	u16 retcode[8];
  };
  
  struct rt_sigframe
  {
  	struct siginfo info;
  	struct ucontext uc;
  	u16 retcode[8];
  };
  
  #ifdef CONFIG_SH_FPU
  static inline int restore_sigcontext_fpu(struct sigcontext __user *sc)
  {
  	struct task_struct *tsk = current;

  	if (!(boot_cpu_data.flags & CPU_HAS_FPU))

  		return 0;
  
  	set_used_math();

  	return __copy_from_user(&tsk->thread.xstate->hardfpu, &sc->sc_fpregs[0],

  				sizeof(long)*(16*2+2));
  }
  
  static inline int save_sigcontext_fpu(struct sigcontext __user *sc,
  				      struct pt_regs *regs)
  {
  	struct task_struct *tsk = current;

  	if (!(boot_cpu_data.flags & CPU_HAS_FPU))

  		return 0;
  
  	if (!used_math()) {
  		__put_user(0, &sc->sc_ownedfp);
  		return 0;
  	}
  
  	__put_user(1, &sc->sc_ownedfp);
  
  	/* This will cause a "finit" to be triggered by the next
  	   attempted FPU operation by the 'current' process.
  	   */
  	clear_used_math();
  
  	unlazy_fpu(tsk, regs);

  	return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.xstate->hardfpu,

  			      sizeof(long)*(16*2+2));
  }
  #endif /* CONFIG_SH_FPU */
  
  static int
  restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc, int *r0_p)
  {
  	unsigned int err = 0;
  
  #define COPY(x)		err |= __get_user(regs->x, &sc->sc_##x)
  			COPY(regs[1]);
  	COPY(regs[2]);	COPY(regs[3]);
  	COPY(regs[4]);	COPY(regs[5]);
  	COPY(regs[6]);	COPY(regs[7]);
  	COPY(regs[8]);	COPY(regs[9]);
  	COPY(regs[10]);	COPY(regs[11]);
  	COPY(regs[12]);	COPY(regs[13]);
  	COPY(regs[14]);	COPY(regs[15]);
  	COPY(gbr);	COPY(mach);
  	COPY(macl);	COPY(pr);
  	COPY(sr);	COPY(pc);
  #undef COPY
  
  #ifdef CONFIG_SH_FPU

  	if (boot_cpu_data.flags & CPU_HAS_FPU) {

  		int owned_fp;
  		struct task_struct *tsk = current;
  
  		regs->sr |= SR_FD; /* Release FPU */
  		clear_fpu(tsk, regs);
  		clear_used_math();
  		__get_user (owned_fp, &sc->sc_ownedfp);
  		if (owned_fp)
  			err |= restore_sigcontext_fpu(sc);
  	}
  #endif
  
  	regs->tra = -1;		/* disable syscall checks */
  	err |= __get_user(*r0_p, &sc->sc_regs[0]);
  	return err;
  }
  
  asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
  			     unsigned long r6, unsigned long r7,

  			     struct pt_regs __regs)

  {

  	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
  	struct sigframe __user *frame = (struct sigframe __user *)regs->regs[15];

  	sigset_t set;
  	int r0;

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

  	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
  		goto badframe;
  
  	if (__get_user(set.sig[0], &frame->sc.oldmask)
  	    || (_NSIG_WORDS > 1
  		&& __copy_from_user(&set.sig[1], &frame->extramask,
  				    sizeof(frame->extramask))))
  		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->sc, &r0))

  		goto badframe;
  	return r0;
  
  badframe:
  	force_sig(SIGSEGV, current);
  	return 0;
  }
  
  asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
  				unsigned long r6, unsigned long r7,

  				struct pt_regs __regs)

  {

  	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
  	struct rt_sigframe __user *frame = (struct rt_sigframe __user *)regs->regs[15];

  	sigset_t set;

  	int r0;

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

  	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->regs[15]) == -EFAULT)

  		goto badframe;

  
  	return r0;
  
  badframe:
  	force_sig(SIGSEGV, current);
  	return 0;

  }

  
  /*
   * Set up a signal frame.
   */
  
  static int
  setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
  		 unsigned long mask)
  {
  	int err = 0;
  
  #define COPY(x)		err |= __put_user(regs->x, &sc->sc_##x)
  	COPY(regs[0]);	COPY(regs[1]);
  	COPY(regs[2]);	COPY(regs[3]);
  	COPY(regs[4]);	COPY(regs[5]);
  	COPY(regs[6]);	COPY(regs[7]);
  	COPY(regs[8]);	COPY(regs[9]);
  	COPY(regs[10]);	COPY(regs[11]);
  	COPY(regs[12]);	COPY(regs[13]);
  	COPY(regs[14]);	COPY(regs[15]);
  	COPY(gbr);	COPY(mach);
  	COPY(macl);	COPY(pr);
  	COPY(sr);	COPY(pc);
  #undef COPY
  
  #ifdef CONFIG_SH_FPU
  	err |= save_sigcontext_fpu(sc, regs);
  #endif
  
  	/* non-iBCS2 extensions.. */
  	err |= __put_user(mask, &sc->oldmask);
  
  	return err;
  }
  
  /*
   * Determine which stack to use..
   */
  static inline void __user *
  get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
  {
  	if (ka->sa.sa_flags & SA_ONSTACK) {
  		if (sas_ss_flags(sp) == 0)
  			sp = current->sas_ss_sp + current->sas_ss_size;
  	}

  	return (void __user *)((sp - (frame_size+UNWINDGUARD)) & -8ul);

  }

  /* These symbols are defined with the addresses in the vsyscall page.
     See vsyscall-trapa.S.  */

  extern void __kernel_sigreturn(void);
  extern void __kernel_rt_sigreturn(void);

  static int setup_frame(int sig, struct k_sigaction *ka,

  			sigset_t *set, struct pt_regs *regs)
  {
  	struct sigframe __user *frame;
  	int err = 0;
  	int signal;
  
  	frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
  
  	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  		goto give_sigsegv;
  
  	signal = current_thread_info()->exec_domain
  		&& current_thread_info()->exec_domain->signal_invmap
  		&& sig < 32
  		? current_thread_info()->exec_domain->signal_invmap[sig]
  		: sig;
  
  	err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);

  	if (_NSIG_WORDS > 1)

  		err |= __copy_to_user(frame->extramask, &set->sig[1],
  				      sizeof(frame->extramask));

  
  	/* Set up to return from userspace.  If provided, use a stub
  	   already in userspace.  */
  	if (ka->sa.sa_flags & SA_RESTORER) {
  		regs->pr = (unsigned long) ka->sa.sa_restorer;

  #ifdef CONFIG_VSYSCALL
  	} else if (likely(current->mm->context.vdso)) {
  		regs->pr = VDSO_SYM(&__kernel_sigreturn);
  #endif

  	} else {
  		/* Generate return code (system call to sigreturn) */
  		err |= __put_user(MOVW(7), &frame->retcode[0]);

  		err |= __put_user(TRAP_NOARG, &frame->retcode[1]);

  		err |= __put_user(OR_R0_R0, &frame->retcode[2]);
  		err |= __put_user(OR_R0_R0, &frame->retcode[3]);
  		err |= __put_user(OR_R0_R0, &frame->retcode[4]);
  		err |= __put_user(OR_R0_R0, &frame->retcode[5]);
  		err |= __put_user(OR_R0_R0, &frame->retcode[6]);
  		err |= __put_user((__NR_sigreturn), &frame->retcode[7]);
  		regs->pr = (unsigned long) frame->retcode;

  		flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));

  	}
  
  	if (err)
  		goto give_sigsegv;
  
  	/* Set up registers for signal handler */
  	regs->regs[15] = (unsigned long) frame;
  	regs->regs[4] = signal; /* Arg for signal handler */
  	regs->regs[5] = 0;
  	regs->regs[6] = (unsigned long) &frame->sc;

  
  	if (current->personality & FDPIC_FUNCPTRS) {
  		struct fdpic_func_descriptor __user *funcptr =
  			(struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
  
  		__get_user(regs->pc, &funcptr->text);
  		__get_user(regs->regs[12], &funcptr->GOT);
  	} else
  		regs->pc = (unsigned long)ka->sa.sa_handler;

  
  	set_fs(USER_DS);

  	pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx
  ",

  		 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);

  	return 0;

  
  give_sigsegv:
  	force_sigsegv(sig, current);

  	return -EFAULT;

  }

  static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,

  			   sigset_t *set, struct pt_regs *regs)
  {
  	struct rt_sigframe __user *frame;
  	int err = 0;
  	int signal;
  
  	frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
  
  	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
  		goto give_sigsegv;
  
  	signal = current_thread_info()->exec_domain
  		&& current_thread_info()->exec_domain->signal_invmap
  		&& sig < 32
  		? current_thread_info()->exec_domain->signal_invmap[sig]
  		: sig;
  
  	err |= copy_siginfo_to_user(&frame->info, info);
  
  	/* Create the ucontext.  */
  	err |= __put_user(0, &frame->uc.uc_flags);

  	err |= __put_user(NULL, &frame->uc.uc_link);

  	err |= __put_user((void *)current->sas_ss_sp,
  			  &frame->uc.uc_stack.ss_sp);
  	err |= __put_user(sas_ss_flags(regs->regs[15]),
  			  &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, set->sig[0]);
  	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
  
  	/* Set up to return from userspace.  If provided, use a stub
  	   already in userspace.  */
  	if (ka->sa.sa_flags & SA_RESTORER) {
  		regs->pr = (unsigned long) ka->sa.sa_restorer;

  #ifdef CONFIG_VSYSCALL
  	} else if (likely(current->mm->context.vdso)) {
  		regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
  #endif

  	} else {
  		/* Generate return code (system call to rt_sigreturn) */
  		err |= __put_user(MOVW(7), &frame->retcode[0]);

  		err |= __put_user(TRAP_NOARG, &frame->retcode[1]);

  		err |= __put_user(OR_R0_R0, &frame->retcode[2]);
  		err |= __put_user(OR_R0_R0, &frame->retcode[3]);
  		err |= __put_user(OR_R0_R0, &frame->retcode[4]);
  		err |= __put_user(OR_R0_R0, &frame->retcode[5]);
  		err |= __put_user(OR_R0_R0, &frame->retcode[6]);
  		err |= __put_user((__NR_rt_sigreturn), &frame->retcode[7]);
  		regs->pr = (unsigned long) frame->retcode;

  		flush_icache_range(regs->pr, regs->pr + sizeof(frame->retcode));

  	}
  
  	if (err)
  		goto give_sigsegv;
  
  	/* Set up registers for signal handler */
  	regs->regs[15] = (unsigned long) frame;
  	regs->regs[4] = signal; /* Arg for signal handler */
  	regs->regs[5] = (unsigned long) &frame->info;
  	regs->regs[6] = (unsigned long) &frame->uc;

  
  	if (current->personality & FDPIC_FUNCPTRS) {
  		struct fdpic_func_descriptor __user *funcptr =
  			(struct fdpic_func_descriptor __user *)ka->sa.sa_handler;
  
  		__get_user(regs->pc, &funcptr->text);
  		__get_user(regs->regs[12], &funcptr->GOT);
  	} else
  		regs->pc = (unsigned long)ka->sa.sa_handler;

  
  	set_fs(USER_DS);

  	pr_debug("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lx
  ",

  		 current->comm, task_pid_nr(current), frame, regs->pc, regs->pr);

  	return 0;

  
  give_sigsegv:
  	force_sigsegv(sig, current);

  	return -EFAULT;

  }

  static inline void
  handle_syscall_restart(unsigned long save_r0, struct pt_regs *regs,
  		       struct sigaction *sa)
  {
  	/* If we're not from a syscall, bail out */
  	if (regs->tra < 0)
  		return;
  
  	/* check for system call restart.. */
  	switch (regs->regs[0]) {
  		case -ERESTART_RESTARTBLOCK:
  		case -ERESTARTNOHAND:
  		no_system_call_restart:
  			regs->regs[0] = -EINTR;

  			break;
  
  		case -ERESTARTSYS:
  			if (!(sa->sa_flags & SA_RESTART))
  				goto no_system_call_restart;
  		/* fallthrough */
  		case -ERESTARTNOINTR:
  			regs->regs[0] = save_r0;

  			regs->pc -= instruction_size(__raw_readw(regs->pc - 4));

  			break;
  	}
  }

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

  static int

  handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info,

  	      sigset_t *oldset, struct pt_regs *regs, unsigned int save_r0)

  {

  	int ret;

  	/* Set up the stack frame */
  	if (ka->sa.sa_flags & SA_SIGINFO)

  		ret = setup_rt_frame(sig, ka, info, oldset, regs);

  	else

  		ret = setup_frame(sig, ka, oldset, regs);

  
  	if (ka->sa.sa_flags & SA_ONESHOT)
  		ka->sa.sa_handler = SIG_DFL;

  	if (ret == 0) {
  		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.
   *
   * Note that we go through the signals twice: once to check the signals that
   * the kernel can handle, and then we build all the user-level signal handling
   * stack-frames in one go after that.
   */

  static void do_signal(struct pt_regs *regs, unsigned int save_r0)

  {
  	siginfo_t info;
  	int signr;
  	struct k_sigaction ka;

  	sigset_t *oldset;

  
  	/*
  	 * We want the common case to go fast, which
  	 * is why we may in certain cases get here from
  	 * kernel mode. Just return without doing anything
  	 * if so.
  	 */
  	if (!user_mode(regs))

  		return;

  	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) {

  		handle_syscall_restart(save_r0, regs, &ka.sa);

  		/* Whee!  Actually deliver the signal.  */

  		if (handle_signal(signr, &ka, &info, oldset,
  				  regs, save_r0) == 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;

  
  			tracehook_signal_handler(signr, &info, &ka, regs,
  					test_thread_flag(TIF_SINGLESTEP));

  		}

  
  		return;

  	}

  	/* Did we come from a system call? */
  	if (regs->tra >= 0) {
  		/* Restart the system call - no handlers present */
  		if (regs->regs[0] == -ERESTARTNOHAND ||
  		    regs->regs[0] == -ERESTARTSYS ||

  		    regs->regs[0] == -ERESTARTNOINTR) {

  			regs->regs[0] = save_r0;

  			regs->pc -= instruction_size(__raw_readw(regs->pc - 4));

  		} else if (regs->regs[0] == -ERESTART_RESTARTBLOCK) {

  			regs->pc -= instruction_size(__raw_readw(regs->pc - 4));

  			regs->regs[3] = __NR_restart_syscall;

  		}
  	}

  	/*
  	 * If there's no signal to deliver, we 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);
  	}
  }
  
  asmlinkage void do_notify_resume(struct pt_regs *regs, unsigned int save_r0,

  				 unsigned long thread_info_flags)

  {
  	/* deal with pending signal delivery */

  	if (thread_info_flags & _TIF_SIGPENDING)

  		do_signal(regs, save_r0);

  
  	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
  		clear_thread_flag(TIF_NOTIFY_RESUME);
  		tracehook_notify_resume(regs);

  		if (current->replacement_session_keyring)
  			key_replace_session_keyring();

  	}

  }