/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1991, 1992  Linus Torvalds
 * Copyright (C) 1994 - 2000  Ralf Baechle
 * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
 */
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/personality.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 <asm/asm.h>
#include <asm/bitops.h>
#include <asm/cacheflush.h>
#include <asm/fpu.h>
#include <asm/sim.h>
#include <asm/uaccess.h>
#include <asm/ucontext.h>

#define DEBUG_SIG 0

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

extern asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs);

extern asmlinkage void do_syscall_trace(void);

/*
 * Atomically swap in the new signal mask, and wait for a signal.
 */

#ifdef CONFIG_TRAD_SIGNALS
save_static_function(sys_sigsuspend);
static_unused int _sys_sigsuspend(struct pt_regs regs)
{
	sigset_t *uset, saveset, newset;

	uset = (sigset_t *) regs.regs[4];
	if (copy_from_user(&newset, uset, sizeof(sigset_t)))
		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.regs[2] = EINTR;
	regs.regs[7] = 1;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(&saveset, &regs))
			return -EINTR;
	}
}
#endif

save_static_function(sys_rt_sigsuspend);
static_unused int _sys_rt_sigsuspend(nabi_no_regargs struct pt_regs regs)
{
	sigset_t *unewset, saveset, newset;
	size_t sigsetsize;

	/* XXX Don't preclude handling different sized sigset_t's.  */
	sigsetsize = regs.regs[5];
	if (sigsetsize != sizeof(sigset_t))
		return -EINVAL;

	unewset = (sigset_t *) regs.regs[4];
	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.regs[2] = EINTR;
	regs.regs[7] = 1;
	while (1) {
		current->state = TASK_INTERRUPTIBLE;
		schedule();
		if (do_signal(&saveset, &regs))
			return -EINTR;
	}
}

#ifdef CONFIG_TRAD_SIGNALS
asmlinkage int sys_sigaction(int sig, const struct sigaction *act,
	struct sigaction *oact)
{
	struct k_sigaction new_ka, old_ka;
	int ret;
	int err = 0;

	if (act) {
		old_sigset_t mask;

		if (!access_ok(VERIFY_READ, act, sizeof(*act)))
			return -EFAULT;
		err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
		err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
		err |= __get_user(mask, &act->sa_mask.sig[0]);
		if (err)
			return -EFAULT;

		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)))
                        return -EFAULT;
		err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
		err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
		err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
		err |= __put_user(0, &oact->sa_mask.sig[1]);
		err |= __put_user(0, &oact->sa_mask.sig[2]);
		err |= __put_user(0, &oact->sa_mask.sig[3]);
		if (err)
			return -EFAULT;
	}

	return ret;
}
#endif

asmlinkage int sys_sigaltstack(nabi_no_regargs struct pt_regs regs)
{
	const stack_t *uss = (const stack_t *) regs.regs[4];
	stack_t *uoss = (stack_t *) regs.regs[5];
	unsigned long usp = regs.regs[29];

	return do_sigaltstack(uss, uoss, usp);
}

asmlinkage int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
{
	int err = 0;

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

	err |= __get_user(regs->cp0_epc, &sc->sc_pc);
	err |= __get_user(regs->hi, &sc->sc_mdhi);
	err |= __get_user(regs->lo, &sc->sc_mdlo);

#define restore_gp_reg(i) do {						\
	err |= __get_user(regs->regs[i], &sc->sc_regs[i]);		\
} while(0)
	restore_gp_reg( 1); restore_gp_reg( 2); restore_gp_reg( 3);
	restore_gp_reg( 4); restore_gp_reg( 5); restore_gp_reg( 6);
	restore_gp_reg( 7); restore_gp_reg( 8); restore_gp_reg( 9);
	restore_gp_reg(10); restore_gp_reg(11); restore_gp_reg(12);
	restore_gp_reg(13); restore_gp_reg(14); restore_gp_reg(15);
	restore_gp_reg(16); restore_gp_reg(17); restore_gp_reg(18);
	restore_gp_reg(19); restore_gp_reg(20); restore_gp_reg(21);
	restore_gp_reg(22); restore_gp_reg(23); restore_gp_reg(24);
	restore_gp_reg(25); restore_gp_reg(26); restore_gp_reg(27);
	restore_gp_reg(28); restore_gp_reg(29); restore_gp_reg(30);
	restore_gp_reg(31);
#undef restore_gp_reg

	err |= __get_user(current->used_math, &sc->sc_used_math);

	if (current->used_math) {
		/* restore fpu context if we have used it before */
		own_fpu();
		err |= restore_fp_context(sc);
	} else {
		/* signal handler may have used FPU.  Give it up. */
		lose_fpu();
	}

	return err;
}

#ifdef CONFIG_TRAD_SIGNALS
struct sigframe {
	u32 sf_ass[4];			/* argument save space for o32 */
	u32 sf_code[2];			/* signal trampoline */
	struct sigcontext sf_sc;
	sigset_t sf_mask;
};
#endif

struct rt_sigframe {
	u32 rs_ass[4];			/* argument save space for o32 */
	u32 rs_code[2];			/* signal trampoline */
	struct siginfo rs_info;
	struct ucontext rs_uc;
};

#ifdef CONFIG_TRAD_SIGNALS
asmlinkage void sys_sigreturn(struct pt_regs regs)
{
	struct sigframe *frame;
	sigset_t blocked;

	frame = (struct sigframe *) regs.regs[29];
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&blocked, &frame->sf_mask, 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->sf_sc))
		goto badframe;

	/*
	 * Don't let your children do this ...
	 */
	if (current_thread_info()->flags & TIF_SYSCALL_TRACE)
		do_syscall_trace();
	__asm__ __volatile__(
		"move\t$29, %0\n\t"
		"j\tsyscall_exit"
		:/* no outputs */
		:"r" (&regs));
	/* Unreached */

badframe:
	force_sig(SIGSEGV, current);
}
#endif

asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
{
	struct rt_sigframe *frame;
	sigset_t set;
	stack_t st;

	frame = (struct rt_sigframe *) regs.regs[29];
	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__copy_from_user(&set, &frame->rs_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->rs_uc.uc_mcontext))
		goto badframe;

	if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
		goto badframe;
	/* It is more difficult to avoid calling this function than to
	   call it and ignore errors.  */
	do_sigaltstack(&st, NULL, regs.regs[29]);

	/*
	 * Don't let your children do this ...
	 */
	__asm__ __volatile__(
		"move\t$29, %0\n\t"
		"j\tsyscall_exit"
		:/* no outputs */
		:"r" (&regs));
	/* Unreached */

badframe:
	force_sig(SIGSEGV, current);
}

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

	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
	err |= __put_user(regs->cp0_status, &sc->sc_status);

#define save_gp_reg(i) do {						\
	err |= __put_user(regs->regs[i], &sc->sc_regs[i]);		\
} while(0)
	__put_user(0, &sc->sc_regs[0]); save_gp_reg(1); save_gp_reg(2);
	save_gp_reg(3); save_gp_reg(4); save_gp_reg(5); save_gp_reg(6);
	save_gp_reg(7); save_gp_reg(8); save_gp_reg(9); save_gp_reg(10);
	save_gp_reg(11); save_gp_reg(12); save_gp_reg(13); save_gp_reg(14);
	save_gp_reg(15); save_gp_reg(16); save_gp_reg(17); save_gp_reg(18);
	save_gp_reg(19); save_gp_reg(20); save_gp_reg(21); save_gp_reg(22);
	save_gp_reg(23); save_gp_reg(24); save_gp_reg(25); save_gp_reg(26);
	save_gp_reg(27); save_gp_reg(28); save_gp_reg(29); save_gp_reg(30);
	save_gp_reg(31);
#undef save_gp_reg

	err |= __put_user(regs->hi, &sc->sc_mdhi);
	err |= __put_user(regs->lo, &sc->sc_mdlo);
	err |= __put_user(regs->cp0_cause, &sc->sc_cause);
	err |= __put_user(regs->cp0_badvaddr, &sc->sc_badvaddr);

	err |= __put_user(current->used_math, &sc->sc_used_math);

	if (!current->used_math)
		goto out;

	/*
	 * Save FPU state to signal context.  Signal handler will "inherit"
	 * current FPU state.
	 */
	if (!is_fpu_owner()) {
		own_fpu();
		restore_fp(current);
	}
	err |= save_fp_context(sc);

out:
	return err;
}

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

	/* Default to using normal stack */
	sp = regs->regs[29];

	/*
 	 * FPU emulator may have it's own trampoline active just
 	 * above the user stack, 16-bytes before the next lowest
 	 * 16 byte boundary.  Try to avoid trashing it.
 	 */
 	sp -= 32;

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

	return (void *)((sp - frame_size) & ALMASK);
}

#ifdef CONFIG_TRAD_SIGNALS
static void inline setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
	int signr, sigset_t *set)
{
	struct sigframe *frame;
	int err = 0;

	frame = get_sigframe(ka, regs, sizeof(*frame));
	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
		goto give_sigsegv;

	/*
	 * Set up the return code ...
	 *
	 *         li      v0, __NR_sigreturn
	 *         syscall
	 */
	err |= __put_user(0x24020000 + __NR_sigreturn, frame->sf_code + 0);
	err |= __put_user(0x0000000c                 , frame->sf_code + 1);
	flush_cache_sigtramp((unsigned long) frame->sf_code);

	err |= setup_sigcontext(regs, &frame->sf_sc);
	err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
	if (err)
		goto give_sigsegv;

	/*
	 * Arguments to signal handler:
	 *
	 *   a0 = signal number
	 *   a1 = 0 (should be cause)
	 *   a2 = pointer to struct sigcontext
	 *
	 * $25 and c0_epc point to the signal handler, $29 points to the
	 * struct sigframe.
	 */
	regs->regs[ 4] = signr;
	regs->regs[ 5] = 0;
	regs->regs[ 6] = (unsigned long) &frame->sf_sc;
	regs->regs[29] = (unsigned long) frame;
	regs->regs[31] = (unsigned long) frame->sf_code;
	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
	       current->comm, current->pid,
	       frame, regs->cp0_epc, frame->regs[31]);
#endif
        return;

give_sigsegv:
	if (signr == SIGSEGV)
		ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV, current);
}
#endif

static void inline setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
	int signr, sigset_t *set, siginfo_t *info)
{
	struct rt_sigframe *frame;
	int err = 0;

	frame = get_sigframe(ka, regs, sizeof(*frame));
	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
		goto give_sigsegv;

	/*
	 * Set up the return code ...
	 *
	 *         li      v0, __NR_rt_sigreturn
	 *         syscall
	 */
	err |= __put_user(0x24020000 + __NR_rt_sigreturn, frame->rs_code + 0);
	err |= __put_user(0x0000000c                    , frame->rs_code + 1);
	flush_cache_sigtramp((unsigned long) frame->rs_code);

	/* Create siginfo.  */
	err |= copy_siginfo_to_user(&frame->rs_info, info);

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->rs_uc.uc_flags);
	err |= __put_user(0, &frame->rs_uc.uc_link);
	err |= __put_user((void *)current->sas_ss_sp,
	                  &frame->rs_uc.uc_stack.ss_sp);
	err |= __put_user(sas_ss_flags(regs->regs[29]),
	                  &frame->rs_uc.uc_stack.ss_flags);
	err |= __put_user(current->sas_ss_size,
	                  &frame->rs_uc.uc_stack.ss_size);
	err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
	err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));

	if (err)
		goto give_sigsegv;

	/*
	 * Arguments to signal handler:
	 *
	 *   a0 = signal number
	 *   a1 = 0 (should be cause)
	 *   a2 = pointer to ucontext
	 *
	 * $25 and c0_epc point to the signal handler, $29 points to
	 * the struct rt_sigframe.
	 */
	regs->regs[ 4] = signr;
	regs->regs[ 5] = (unsigned long) &frame->rs_info;
	regs->regs[ 6] = (unsigned long) &frame->rs_uc;
	regs->regs[29] = (unsigned long) frame;
	regs->regs[31] = (unsigned long) frame->rs_code;
	regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;

#if DEBUG_SIG
	printk("SIG deliver (%s:%d): sp=0x%p pc=0x%lx ra=0x%p\n",
	       current->comm, current->pid,
	       frame, regs->cp0_epc, regs->regs[31]);
#endif
	return;

give_sigsegv:
	if (signr == SIGSEGV)
		ka->sa.sa_handler = SIG_DFL;
	force_sig(SIGSEGV, current);
}

extern void setup_rt_frame_n32(struct k_sigaction * ka,
	struct pt_regs *regs, int signr, sigset_t *set, siginfo_t *info);

static inline void handle_signal(unsigned long sig, siginfo_t *info,
	sigset_t *oldset, struct pt_regs *regs)
{
	struct k_sigaction *ka = &current->sighand->action[sig-1];

	switch(regs->regs[0]) {
	case ERESTART_RESTARTBLOCK:
	case ERESTARTNOHAND:
		regs->regs[2] = EINTR;
		break;
	case ERESTARTSYS:
		if(!(ka->sa.sa_flags & SA_RESTART)) {
			regs->regs[2] = EINTR;
			break;
		}
	/* fallthrough */
	case ERESTARTNOINTR:		/* Userland will reload $v0.  */
		regs->regs[7] = regs->regs[26];
		regs->cp0_epc -= 8;
	}

	regs->regs[0] = 0;		/* Don't deal with this again.  */

#ifdef CONFIG_TRAD_SIGNALS
	if (ka->sa.sa_flags & SA_SIGINFO) {
#else
	if (1) {
#endif
#ifdef CONFIG_MIPS32_N32
		if ((current->thread.mflags & MF_ABI_MASK) == MF_N32)
			setup_rt_frame_n32 (ka, regs, sig, oldset, info);
		else
#endif
			setup_rt_frame(ka, regs, sig, oldset, info);
	}
#ifdef CONFIG_TRAD_SIGNALS
	else
		setup_frame(ka, regs, sig, oldset);
#endif

	if (ka->sa.sa_flags & SA_ONESHOT)
		ka->sa.sa_handler = SIG_DFL;
	if (!(ka->sa.sa_flags & SA_NODEFER)) {
		spin_lock_irq(&current->sighand->siglock);
		sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
		sigaddset(&current->blocked,sig);
		recalc_sigpending();
		spin_unlock_irq(&current->sighand->siglock);
	}
}

extern int do_signal32(sigset_t *oldset, struct pt_regs *regs);
extern int do_irix_signal(sigset_t *oldset, struct pt_regs *regs);

asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs)
{
	siginfo_t info;
	int signr;

#ifdef CONFIG_BINFMT_ELF32
	if ((current->thread.mflags & MF_ABI_MASK) == MF_O32) {
		return do_signal32(oldset, regs);
	}
#endif

	if (!oldset)
		oldset = &current->blocked;

	signr = get_signal_to_deliver(&info, regs, NULL);
	if (signr > 0) {
		handle_signal(signr, &info, oldset, regs);
		return 1;
	}

	/*
	 * Who's code doesn't conform to the restartable syscall convention
	 * dies here!!!  The li instruction, a single machine instruction,
	 * must directly be followed by the syscall instruction.
	 */
	if (regs->regs[0]) {
		if (regs->regs[2] == ERESTARTNOHAND ||
		    regs->regs[2] == ERESTARTSYS ||
		    regs->regs[2] == ERESTARTNOINTR) {
			regs->regs[7] = regs->regs[26];
			regs->cp0_epc -= 8;
		}
		if (regs->regs[2] == ERESTART_RESTARTBLOCK) {
			regs->regs[2] = __NR_restart_syscall;
			regs->regs[7] = regs->regs[26];
			regs->cp0_epc -= 4;
		}
	}
	return 0;
}

extern int do_irix_signal(sigset_t *oldset, struct pt_regs *regs);

/*
 * notification of userspace execution resumption
 * - triggered by current->work.notify_resume
 */
asmlinkage void do_notify_resume(struct pt_regs *regs, sigset_t *oldset,
	__u32 thread_info_flags)
{
	/* deal with pending signal delivery */
	if (thread_info_flags & _TIF_SIGPENDING) {
#ifdef CONFIG_BINFMT_ELF32
		if (likely((current->thread.mflags & MF_ABI_MASK) == MF_O32)) {
			do_signal32(oldset, regs);
			return;
		}
#endif
#ifdef CONFIG_BINFMT_IRIX
		if (unlikely(current->personality != PER_LINUX)) {
			do_irix_signal(oldset, regs);
			return;
		}
#endif
		do_signal(oldset, regs);
	}
}