// TODO coprocessor stuff/* *  linux/arch/xtensa/kernel/signal.c * *  Copyright (C) 1991, 1992  Linus Torvalds *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson * *  Joe Taylor <joe@tensilica.com> *  Chris Zankel <chris@zankel.net> * * * */#include <xtensa/config/core.h>#include <xtensa/hal.h>#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/ptrace.h>#include <linux/unistd.h>#include <linux/stddef.h>#include <linux/personality.h>#include <asm/ucontext.h>#include <asm/uaccess.h>#include <asm/pgtable.h>#include <asm/cacheflush.h>#define DEBUG_SIG  0#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options,			  struct rusage * ru);asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);extern struct task_struct *coproc_owners[];/* * Atomically swap in the new signal mask, and wait for a signal. */int sys_sigsuspend(struct pt_regs *regs){	old_sigset_t mask = (old_sigset_t) regs->areg[3];	sigset_t saveset;	mask &= _BLOCKABLE;	spin_lock_irq(&current->sighand->siglock);	saveset = current->blocked;	siginitset(&current->blocked, mask);	recalc_sigpending();	spin_unlock_irq(&current->sighand->siglock);	regs->areg[2] = -EINTR;	while (1) {		current->state = TASK_INTERRUPTIBLE;		schedule();		if (do_signal(regs, &saveset))			return -EINTR;	}}asmlinkage intsys_rt_sigsuspend(struct pt_regs *regs){	sigset_t *unewset = (sigset_t *) regs->areg[4];	size_t sigsetsize = (size_t) regs->areg[3];	sigset_t saveset, newset;	/* XXX: Don't preclude handling different sized sigset_t's.  */	if (sigsetsize != sizeof(sigset_t))		return -EINVAL;	if (copy_from_user(&newset, unewset, sizeof(newset)))		return -EFAULT;	sigdelsetmask(&newset, ~_BLOCKABLE);	spin_lock_irq(&current->sighand->siglock);	saveset = current->blocked;	current->blocked = newset;	recalc_sigpending();	spin_unlock_irq(&current->sighand->siglock);	regs->areg[2] = -EINTR;	while (1) {		current->state = TASK_INTERRUPTIBLE;		schedule();		if (do_signal(regs, &saveset))			return -EINTR;	}}asmlinkage intsys_sigaction(int sig, const struct old_sigaction *act,	      struct old_sigaction *oact){	struct k_sigaction new_ka, old_ka;	int ret;	if (act) {		old_sigset_t mask;		if (verify_area(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 (verify_area(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 intsys_sigaltstack(struct pt_regs *regs){	const stack_t *uss = (stack_t *) regs->areg[4];	stack_t *uoss = (stack_t *) regs->areg[3];	if (regs->depc > 64)		panic ("Double exception sys_sigreturn\n");	return do_sigaltstack(uss, uoss, regs->areg[1]);}/* * Do a signal return; undo the signal stack. */struct sigframe{	struct sigcontext sc;	struct _cpstate cpstate;	unsigned long extramask[_NSIG_WORDS-1];	unsigned char retcode[6];	unsigned int reserved[4]; /* Reserved area for chaining */	unsigned int window[4]; /* Window of 4 registers for initial context */};struct rt_sigframe{	struct siginfo info;	struct ucontext uc;	struct _cpstate cpstate;	unsigned char retcode[6];	unsigned int reserved[4]; /* Reserved area for chaining */	unsigned int window[4]; /* Window of 4 registers for initial context */};extern void release_all_cp (struct task_struct *);// FIXME restore_cpextrastatic inline intrestore_cpextra (struct _cpstate *buf){#if 0	/* The signal handler may have used coprocessors in which	 * case they are still enabled.  We disable them to force a	 * reloading of the original task's CP state by the lazy	 * context-switching mechanisms of CP exception handling.	 * Also, we essentially discard any coprocessor state that the	 * signal handler created. */	struct task_struct *tsk = current;	release_all_cp(tsk);	return __copy_from_user(tsk->thread.cpextra, buf, XTENSA_CP_EXTRA_SIZE);#endif	return 0;}/* Note: We don't copy double exception 'tregs', we have to finish double exc. first before we return to signal handler! This dbl.exc.handler might cause another double exception, but I think we are fine as the situation is the same as if we had returned to the signal handerl and got an interrupt immediately... */static intrestore_sigcontext(struct pt_regs *regs, struct sigcontext *sc){	struct thread_struct *thread;	unsigned int err = 0;	unsigned long ps;	struct _cpstate *buf;#define COPY(x)	err |= __get_user(regs->x, &sc->sc_##x)	COPY(pc);	COPY(depc);	COPY(wmask);	COPY(lbeg);	COPY(lend);	COPY(lcount);	COPY(sar);	COPY(windowbase);	COPY(windowstart);#undef COPY	/* For PS, restore only PS.CALLINC.	 * Assume that all other bits are either the same as for the signal	 * handler, or the user mode value doesn't matter (e.g. PS.OWB).	 */	err |= __get_user(ps, &sc->sc_ps);	regs->ps = (regs->ps & ~XCHAL_PS_CALLINC_MASK)		| (ps & XCHAL_PS_CALLINC_MASK);	/* Additional corruption checks */	if ((regs->windowbase >= (XCHAL_NUM_AREGS/4))	|| ((regs->windowstart & ~((1<<(XCHAL_NUM_AREGS/4)) - 1)) != 0) )		err = 1;	if ((regs->lcount > 0)	&& ((regs->lbeg > TASK_SIZE) || (regs->lend > TASK_SIZE)) )		err = 1;	/* Restore extended register state.	 * See struct thread_struct in processor.h.	 */	thread = &current->thread;	err |= __copy_from_user (regs->areg, sc->sc_areg, XCHAL_NUM_AREGS*4);	err |= __get_user(buf, &sc->sc_cpstate);	if (buf) {		if (verify_area(VERIFY_READ, buf, sizeof(*buf)))			goto badframe;		err |= restore_cpextra(buf);	}	regs->syscall = -1;		/* disable syscall checks */	return err;badframe:	return 1;}static inline voidflush_my_cpstate(struct task_struct *tsk){	unsigned long flags;	local_irq_save(flags);#if 0	// FIXME	for (i = 0; i < XCHAL_CP_NUM; i++) {		if (tsk == coproc_owners[i]) {			xthal_validate_cp(i);			xthal_save_cpregs(tsk->thread.cpregs_ptr[i], i);			/* Invalidate and "disown" the cp to allow			 * callers the chance to reset cp state in the			 * task_struct. */			xthal_invalidate_cp(i);			coproc_owners[i] = 0;		}	}#endif	local_irq_restore(flags);}/* Return codes:	0:  nothing saved	1:  stuff to save, successful       -1:  stuff to save, error happened*/static intsave_cpextra (struct _cpstate *buf){#if (XCHAL_EXTRA_SA_SIZE == 0) && (XCHAL_CP_NUM == 0)	return 0;#else	/* FIXME: If a task has never used a coprocessor, there is	 * no need to save and restore anything.  Tracking this	 * information would allow us to optimize this section.	 * Perhaps we can use current->used_math or (current->flags &	 * PF_USEDFPU) or define a new field in the thread	 * structure. */	/* We flush any live, task-owned cp state to the task_struct,	 * then copy it all to the sigframe.  Then we clear all	 * cp/extra state in the task_struct, effectively	 * clearing/resetting all cp/extra state for the signal	 * handler (cp-exception handling will load these new values	 * into the cp/extra registers.)  This step is important for	 * things like a floating-point cp, where the OS must reset	 * the FCR to the default rounding mode. */	int err = 0;	struct task_struct *tsk = current;	flush_my_cpstate(tsk);	/* Note that we just copy everything: 'extra' and 'cp' state together.*/	err |= __copy_to_user(buf, tsk->thread.cp_save, XTENSA_CP_EXTRA_SIZE);	memset(tsk->thread.cp_save, 0, XTENSA_CP_EXTRA_SIZE);#if (XTENSA_CP_EXTRA_SIZE == 0)#error Sanity check on memset above, cpextra_size should not be zero.#endif	return err ? -1 : 1;#endif}static intsetup_sigcontext(struct sigcontext *sc, struct _cpstate *cpstate,		 struct pt_regs *regs, unsigned long mask){	struct thread_struct *thread;	int err = 0;//printk("setup_sigcontext\n");#define COPY(x)	err |= __put_user(regs->x, &sc->sc_##x)	COPY(pc);	COPY(ps);	COPY(depc);	COPY(wmask);	COPY(lbeg);	COPY(lend);	COPY(lcount);	COPY(sar);	COPY(windowbase);	COPY(windowstart);#undef COPY	/* Save extended register state.	 * See struct thread_struct in processor.h.	 */	thread = &current->thread;	err |= __copy_to_user (sc->sc_areg, regs->areg, XCHAL_NUM_AREGS * 4);	err |= save_cpextra(cpstate);	err |= __put_user(err ? NULL : cpstate, &sc->sc_cpstate);	/* non-iBCS2 extensions.. */	err |= __put_user(mask, &sc->oldmask);	return err;}asmlinkage int sys_sigreturn(struct pt_regs *regs){	struct sigframe *frame = (struct sigframe *)regs->areg[1];	sigset_t set;	if (regs->depc > 64)