amd64/ia32/ia32_syscall.c

/*-
 * Copyright (C) 1994, David Greenman
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the University of Utah, and William Jolitz.
 *
 * 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.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: head/sys/amd64/ia32/ia32_syscall.c 160773 2006-07-27 22:32:30Z jhb $");

/*
 * 386 Trap and System call handling
 */

#include "opt_clock.h"
#include "opt_cpu.h"
#include "opt_isa.h"
#include "opt_ktrace.h"

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/pioctl.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/ptrace.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/syscall.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/uio.h>
#include <sys/vmmeter.h>
#ifdef KTRACE
#include <sys/ktrace.h>
#endif
#include <security/audit/audit.h>

#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_kern.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_extern.h>

#include <machine/cpu.h>
#include <machine/intr_machdep.h>
#include <machine/md_var.h>

#define	IDTVEC(name)	__CONCAT(X,name)

extern inthand_t IDTVEC(int0x80_syscall), IDTVEC(rsvd);
extern const char *freebsd32_syscallnames[];

void ia32_syscall(struct trapframe frame);	/* Called from asm code */

void
ia32_syscall(struct trapframe frame)
{
	caddr_t params;
	int i;
	struct sysent *callp;
	struct thread *td = curthread;
	struct proc *p = td->td_proc;
	register_t orig_tf_rflags;
	int error;
	int narg;
	u_int32_t args[8];
	u_int64_t args64[8];
	u_int code;
	ksiginfo_t ksi;

	/*
	 * note: PCPU_LAZY_INC() can only be used if we can afford
	 * occassional inaccuracy in the count.
	 */
	PCPU_LAZY_INC(cnt.v_syscall);

	td->td_pticks = 0;
	td->td_frame = &frame;
	if (td->td_ucred != p->p_ucred)
		cred_update_thread(td);
	params = (caddr_t)frame.tf_rsp + sizeof(u_int32_t);
	code = frame.tf_rax;
	orig_tf_rflags = frame.tf_rflags;

	if (p->p_sysent->sv_prepsyscall) {
		/*
		 * The prep code is MP aware.
		 */
		(*p->p_sysent->sv_prepsyscall)(&frame, args, &code, &params);
	} else {
		/*
		 * Need to check if this is a 32 bit or 64 bit syscall.
		 * fuword is MP aware.
		 */
		if (code == SYS_syscall) {
			/*
			 * Code is first argument, followed by actual args.
			 */
			code = fuword32(params);
			params += sizeof(int);
		} else if (code == SYS___syscall) {
			/*
			 * Like syscall, but code is a quad, so as to maintain
			 * quad alignment for the rest of the arguments.
			 * We use a 32-bit fetch in case params is not
			 * aligned.
			 */
			code = fuword32(params);
			params += sizeof(quad_t);
		}
	}

 	if (p->p_sysent->sv_mask)
 		code &= p->p_sysent->sv_mask;

 	if (code >= p->p_sysent->sv_size)
 		callp = &p->p_sysent->sv_table[0];
  	else
 		callp = &p->p_sysent->sv_table[code];

	narg = callp->sy_narg & SYF_ARGMASK;

	/*
	 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware
	 */
	if (params != NULL && narg != 0)
		error = copyin(params, (caddr_t)args,
		    (u_int)(narg * sizeof(int)));
	else
		error = 0;

	for (i = 0; i < narg; i++)
		args64[i] = args[i];

#ifdef KTRACE
	if (KTRPOINT(td, KTR_SYSCALL))
		ktrsyscall(code, narg, args64);
#endif
	CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td,
	    td->td_proc->p_pid, td->td_proc->p_comm, code);

	/*
	 * Try to run the syscall without Giant if the syscall
	 * is MP safe.
	 */
	if ((callp->sy_narg & SYF_MPSAFE) == 0)
		mtx_lock(&Giant);

	if (error == 0) {
		td->td_retval[0] = 0;
		td->td_retval[1] = frame.tf_rdx;

		STOPEVENT(p, S_SCE, narg);

		PTRACESTOP_SC(p, td, S_PT_SCE);

		AUDIT_SYSCALL_ENTER(code, td);
		error = (*callp->sy_call)(td, args64);
		AUDIT_SYSCALL_EXIT(error, td);
	}

	switch (error) {
	case 0:
		frame.tf_rax = td->td_retval[0];
		frame.tf_rdx = td->td_retval[1];
		frame.tf_rflags &= ~PSL_C;
		break;

	case ERESTART:
		/*
		 * Reconstruct pc, assuming lcall $X,y is 7 bytes,
		 * int 0x80 is 2 bytes. We saved this in tf_err.
		 */
		frame.tf_rip -= frame.tf_err;
		break;

	case EJUSTRETURN:
		break;

	default:
 		if (p->p_sysent->sv_errsize) {
 			if (error >= p->p_sysent->sv_errsize)
  				error = -1;	/* XXX */
   			else
  				error = p->p_sysent->sv_errtbl[error];
		}
		frame.tf_rax = error;
		frame.tf_rflags |= PSL_C;
		break;
	}

	/*
	 * Release Giant if we previously set it.
	 */
	if ((callp->sy_narg & SYF_MPSAFE) == 0)
		mtx_unlock(&Giant);

	/*
	 * Traced syscall.
	 */
	if (orig_tf_rflags & PSL_T) {
		frame.tf_rflags &= ~PSL_T;
		ksiginfo_init_trap(&ksi);
		ksi.ksi_signo = SIGTRAP;
		ksi.ksi_code = TRAP_TRACE;
		ksi.ksi_addr = (void *)frame.tf_rip;
		trapsignal(td, &ksi);
	}

	/*
	 * Check for misbehavior.
	 */
	WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
	    (code >= 0 && code < SYS_MAXSYSCALL) ? freebsd32_syscallnames[code] : "???");
	KASSERT(td->td_critnest == 0,
	    ("System call %s returning in a critical section",
	    (code >= 0 && code < SYS_MAXSYSCALL) ? freebsd32_syscallnames[code] : "???"));
	KASSERT(td->td_locks == 0,
	    ("System call %s returning with %d locks held",
	    (code >= 0 && code < SYS_MAXSYSCALL) ? freebsd32_syscallnames[code] : "???",
	    td->td_locks));

	/*
	 * Handle reschedule and other end-of-syscall issues
	 */
	userret(td, &frame);

	CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td,
	    td->td_proc->p_pid, td->td_proc->p_comm, code);
#ifdef KTRACE
	if (KTRPOINT(td, KTR_SYSRET))
		ktrsysret(code, error, td->td_retval[0]);
#endif

	/*
	 * This works because errno is findable through the
	 * register set.  If we ever support an emulation where this
	 * is not the case, this code will need to be revisited.
	 */
	STOPEVENT(p, S_SCX, code);

	PTRACESTOP_SC(p, td, S_PT_SCX);
}


static void
ia32_syscall_enable(void *dummy)
{

 	setidt(IDT_SYSCALL, &IDTVEC(int0x80_syscall), SDT_SYSIGT, SEL_UPL, 0);
}

static void
ia32_syscall_disable(void *dummy)
{

 	setidt(IDT_SYSCALL, &IDTVEC(rsvd), SDT_SYSIGT, SEL_KPL, 0);
}

SYSINIT(ia32_syscall, SI_SUB_EXEC, SI_ORDER_ANY, ia32_syscall_enable, NULL);
SYSUNINIT(ia32_syscall, SI_SUB_EXEC, SI_ORDER_ANY, ia32_syscall_disable, NULL);