/*	$NetBSD: syscall.c,v 1.14 2002/12/21 16:23:58 manu Exp $	*/

/*-
 * Copyright (c) 2001 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe and by Charles M. Hannum.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the NetBSD
 *	Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1992, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department and Ralph Campbell.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * from: Utah Hdr: trap.c 1.32 91/04/06
 *
 *	@(#)trap.c	8.5 (Berkeley) 1/11/94
 */

#include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */

__KERNEL_RCSID(0, "$NetBSD: syscall.c,v 1.14 2002/12/21 16:23:58 manu Exp $");

#if defined(_KERNEL_OPT)
#include "opt_ktrace.h"
#include "opt_systrace.h"
#include "opt_syscall_debug.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/signal.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#ifdef SYSTRACE
#include <sys/systrace.h>
#endif
#include <sys/syscall.h>

#include <uvm/uvm_extern.h>

#include <machine/cpu.h>
#include <mips/trap.h>
#include <mips/reg.h>
#include <mips/regnum.h>			/* symbolic register indices */
#include <mips/userret.h>

#ifndef EMULNAME
#define EMULNAME(x)	(x)
#endif

#ifndef SYSCALL_SHIFT
#define SYSCALL_SHIFT 0
#endif

void	EMULNAME(syscall_intern)(struct proc *);
void	EMULNAME(syscall_plain)(struct proc *, u_int, u_int, u_int);
void	EMULNAME(syscall_fancy)(struct proc *, u_int, u_int, u_int);

vaddr_t MachEmulateBranch(struct frame *, vaddr_t, u_int, int);

#define DELAYBRANCH(x) ((int)(x)<0)

void
EMULNAME(syscall_intern)(struct proc *p)
{
#ifdef KTRACE
	if (p->p_traceflag & (KTRFAC_SYSCALL | KTRFAC_SYSRET)) {
		p->p_md.md_syscall = EMULNAME(syscall_fancy);
		return;
	}
#endif
#ifdef SYSTRACE
	if (ISSET(p->p_flag, P_SYSTRACE)) {
		p->p_md.md_syscall = EMULNAME(syscall_fancy);
		return;
	} 
#endif
	p->p_md.md_syscall = EMULNAME(syscall_plain);
}

/*
 * Process a system call.
 *
 * System calls are strange beasts.  They are passed the syscall number
 * in v0, and the arguments in the registers (as normal).  They return
 * an error flag in a3 (if a3 != 0 on return, the syscall had an error),
 * and the return value (if any) in v0 and possibly v1.
 *
 * XXX Needs to be heavily rototilled for N32 or LP64 support.
 */

void
EMULNAME(syscall_plain)(struct proc *p, u_int status, u_int cause, u_int opc)
{
	struct frame *frame = (struct frame *)p->p_md.md_regs;
	register_t *args, copyargs[8];
	register_t *rval;
#if _MIPS_BSD_API == _MIPS_BSD_API_LP32_64CLEAN
	register_t copyrval[2];
#endif
	mips_reg_t ov0;
	size_t numsys, nsaved, nargs;
	const struct sysent *callp;
	int code, error;

	uvmexp.syscalls++;

	if (DELAYBRANCH(cause))
		frame->f_regs[PC] = MachEmulateBranch(frame, opc, 0, 0);
	else
		frame->f_regs[PC] = opc + sizeof(int);

	callp = p->p_emul->e_sysent;
	numsys = p->p_emul->e_nsysent;
	ov0 = code = frame->f_regs[V0] - SYSCALL_SHIFT;

	switch (code) {
	case SYS_syscall:
	case SYS___syscall:
		args = copyargs;
		if (code == SYS_syscall) {
			/*
			 * Code is first argument, followed by actual args.
			 */
			code = frame->f_regs[A0] - SYSCALL_SHIFT;
			args[0] = frame->f_regs[A1];
			args[1] = frame->f_regs[A2];
			args[2] = frame->f_regs[A3];
			nsaved = 3;
		} else {
			/*
			 * Like syscall, but code is a quad, so as to maintain
			 * quad alignment for the rest of the arguments.
			 */
			code = frame->f_regs[A0 + _QUAD_LOWWORD] 
			    - SYSCALL_SHIFT;
			args[0] = frame->f_regs[A2];
			args[1] = frame->f_regs[A3];
			nsaved = 2;
		}

		if (code >= p->p_emul->e_nsysent)
			callp += p->p_emul->e_nosys;
		else
			callp += code;
		nargs = callp->sy_argsize / sizeof(register_t);

		if (nargs > nsaved) {
			error = copyin(
			    ((register_t *)(vaddr_t)frame->f_regs[SP] + 4),
			    (args + nsaved),
			    (nargs - nsaved) * sizeof(register_t));
			if (error)
				goto bad;
		}
		break;

	default:
		if (code >= p->p_emul->e_nsysent)
			callp += p->p_emul->e_nosys;
		else
			callp += code;
		nargs = callp->sy_narg;

		if (nargs < 5) {
#if !defined(_MIPS_BSD_API) || _MIPS_BSD_API == _MIPS_BSD_API_LP32
			args = (register_t *)&frame->f_regs[A0];
#elif _MIPS_BSD_API == _MIPS_BSD_API_LP32_64CLEAN
			args = copyargs;
			args[0] = frame->f_regs[A0];
			args[1] = frame->f_regs[A1];
			args[2] = frame->f_regs[A2];
			args[3] = frame->f_regs[A3];
#else
# error syscall not implemented for current MIPS ABI
#endif
		} else {
			args = copyargs;
			error = copyin(
			    ((register_t *)(vaddr_t)frame->f_regs[SP] + 4),
			    (&copyargs[4]),
			    (nargs - 4) * sizeof(register_t));
			if (error)
				goto bad;
			args[0] = frame->f_regs[A0];
			args[1] = frame->f_regs[A1];
			args[2] = frame->f_regs[A2];
			args[3] = frame->f_regs[A3];
		}
		break;
	}

#ifdef SYSCALL_DEBUG
	scdebug_call(p, code, (register_t *)args);
#endif

#if !defined(_MIPS_BSD_API) || _MIPS_BSD_API == _MIPS_BSD_API_LP32
	rval = (register_t *)&frame->f_regs[V0];
	rval[0] = 0;
	/* rval[1] already has V1 */
#elif _MIPS_BSD_API == _MIPS_BSD_API_LP32_64CLEAN
	rval = copyrval;
	rval[0] = 0;
	rval[1] = frame->f_regs[V1];
#endif

	error = (*callp->sy_call)(p, args, rval);

	switch (error) {
	case 0:
#if _MIPS_BSD_API == _MIPS_BSD_API_LP32_64CLEAN
		frame->f_regs[V0] = rval[0];
		frame->f_regs[V1] = rval[1];
#endif
		frame->f_regs[A3] = 0;
		break;
	case ERESTART:
		frame->f_regs[V0] = ov0;	/* restore syscall code */
		frame->f_regs[PC] = opc;
		break;
	case EJUSTRETURN:
		break;	/* nothing to do */
	default:
	bad:
		if (p->p_emul->e_errno)
			error = p->p_emul->e_errno[error];
		frame->f_regs[V0] = error;
		frame->f_regs[A3] = 1;
		break;
	}

#ifdef SYSCALL_DEBUG
	scdebug_ret(p, code, error, rval);
#endif

	userret(p);
}

void
EMULNAME(syscall_fancy)(struct proc *p, u_int status, u_int cause, u_int opc)
{
	struct frame *frame = (struct frame *)p->p_md.md_regs;
	register_t *args, copyargs[8];
	register_t *rval;
#if _MIPS_BSD_API == _MIPS_BSD_API_LP32_64CLEAN
	register_t copyrval[2];
#endif
	mips_reg_t ov0;
	size_t numsys, nsaved, nargs;
	const struct sysent *callp;
	int code, error;

	uvmexp.syscalls++;

	if (DELAYBRANCH(cause))
		frame->f_regs[PC] = MachEmulateBranch(frame, opc, 0, 0);
	else
		frame->f_regs[PC] = opc + sizeof(int);

	callp = p->p_emul->e_sysent;
	numsys = p->p_emul->e_nsysent;
	ov0 = code = frame->f_regs[V0] - SYSCALL_SHIFT;

	switch (code) {
	case SYS_syscall:
	case SYS___syscall:
		args = copyargs;
		if (code == SYS_syscall) {
			/*
			 * Code is first argument, followed by actual args.
			 */
			code = frame->f_regs[A0] - SYSCALL_SHIFT;
			args[0] = frame->f_regs[A1];
			args[1] = frame->f_regs[A2];
			args[2] = frame->f_regs[A3];
			nsaved = 3;
		} else {
			/*
			 * Like syscall, but code is a quad, so as to maintain
			 * quad alignment for the rest of the arguments.
			 */
			code = frame->f_regs[A0 + _QUAD_LOWWORD] 
			    - SYSCALL_SHIFT;
			args[0] = frame->f_regs[A2];
			args[1] = frame->f_regs[A3];
			nsaved = 2;
		}

		if (code >= p->p_emul->e_nsysent)
			callp += p->p_emul->e_nosys;
		else
			callp += code;
		nargs = callp->sy_argsize / sizeof(register_t);

		if (nargs > nsaved) {
			error = copyin(
			    ((register_t *)(vaddr_t)frame->f_regs[SP] + 4),
			    (args + nsaved),
			    (nargs - nsaved) * sizeof(register_t));
			if (error)
				goto bad;
		}
		break;

	default:
		if (code >= p->p_emul->e_nsysent)
			callp += p->p_emul->e_nosys;
		else
			callp += code;
		nargs = callp->sy_narg;

		if (nargs < 5) {
#if !defined(_MIPS_BSD_API) || _MIPS_BSD_API == _MIPS_BSD_API_LP32
			args = (register_t *)&frame->f_regs[A0];
#elif _MIPS_BSD_API == _MIPS_BSD_API_LP32_64CLEAN
			args = copyargs;
			args[0] = frame->f_regs[A0];
			args[1] = frame->f_regs[A1];
			args[2] = frame->f_regs[A2];
			args[3] = frame->f_regs[A3];
#else
# error syscall not implemented for current MIPS ABI
#endif
		} else {
			args = copyargs;
			error = copyin(
			    ((register_t *)(vaddr_t)frame->f_regs[SP] + 4),
			    (&copyargs[4]),
			    (nargs - 4) * sizeof(register_t));
			if (error)
				goto bad;
			args[0] = frame->f_regs[A0];
			args[1] = frame->f_regs[A1];
			args[2] = frame->f_regs[A2];
			args[3] = frame->f_regs[A3];
		}
		break;
	}

	if ((error = trace_enter(p, code, code, NULL, args, rval)) != 0)
		goto bad;

#if !defined(_MIPS_BSD_API) || _MIPS_BSD_API == _MIPS_BSD_API_LP32
	rval = (register_t *)&frame->f_regs[V0];
	rval[0] = 0;
	/* rval[1] already has V1 */
#elif _MIPS_BSD_API == _MIPS_BSD_API_LP32_64CLEAN
	rval = copyrval;
	rval[0] = 0;
	rval[1] = frame->f_regs[V1];
#endif

	error = (*callp->sy_call)(p, args, rval);

	switch (error) {
	case 0:
#if _MIPS_BSD_API == _MIPS_BSD_API_LP32_64CLEAN
		frame->f_regs[V0] = rval[0];
		frame->f_regs[V1] = rval[1];
#endif
		frame->f_regs[A3] = 0;
		break;
	case ERESTART:
		frame->f_regs[V0] = ov0;	/* restore syscall code */
		frame->f_regs[PC] = opc;
		break;
	case EJUSTRETURN:
		break;	/* nothing to do */
	default:
	bad:
		if (p->p_emul->e_errno)
			error = p->p_emul->e_errno[error];
		frame->f_regs[V0] = error;
		frame->f_regs[A3] = 1;
		break;
	}

	trace_exit(p, code, args, rval, error);

	userret(p);
}