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syscall.c
174 lines (152 loc) · 4.58 KB
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syscall.c
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/* $NetBSD: syscall.c,v 1.18 2019/04/06 11:54:21 kamil Exp $ */
/*-
* Copyright (c) 1998, 2000, 2009 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* 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.
*
* 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.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: syscall.c,v 1.18 2019/04/06 11:54:21 kamil Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/signal.h>
#include <sys/ktrace.h>
#include <sys/syscall.h>
#include <sys/syscallvar.h>
#include <sys/syscall_stats.h>
#include <uvm/uvm_extern.h>
#include <machine/cpu.h>
#include <machine/psl.h>
#include <machine/userret.h>
#include "opt_dtrace.h"
#ifndef __x86_64__
int x86_copyargs(void *, void *, size_t);
#endif
void syscall_intern(struct proc *);
static void syscall(struct trapframe *);
void
md_child_return(struct lwp *l)
{
struct trapframe *tf = l->l_md.md_regs;
X86_TF_RAX(tf) = 0;
X86_TF_RFLAGS(tf) &= ~PSL_C;
userret(l);
}
/*
* Process the tail end of a posix_spawn() for the child.
*/
void
cpu_spawn_return(struct lwp *l)
{
userret(l);
}
/*
* syscall(frame):
* System call request from POSIX system call gate interface to kernel.
* Like trap(), argument is call by reference.
*/
#ifdef KDTRACE_HOOKS
void syscall(struct trapframe *);
#else
static
#endif
void
syscall(struct trapframe *frame)
{
const struct sysent *callp;
struct proc *p;
struct lwp *l;
int error;
register_t code, rval[2];
#ifdef __x86_64__
/* Verify that the syscall args will fit in the trapframe space */
CTASSERT(offsetof(struct trapframe, tf_arg9) >=
sizeof(register_t) * (2 + SYS_MAXSYSARGS - 1));
#define args (&frame->tf_rdi)
#else
register_t args[2 + SYS_MAXSYSARGS];
#endif
l = curlwp;
p = l->l_proc;
LWP_CACHE_CREDS(l, p);
code = X86_TF_RAX(frame) & (SYS_NSYSENT - 1);
callp = p->p_emul->e_sysent + code;
SYSCALL_COUNT(syscall_counts, code);
SYSCALL_TIME_SYS_ENTRY(l, syscall_times, code);
#ifdef __x86_64__
/*
* The first 6 syscall args are passed in rdi, rsi, rdx, r10, r8 and r9
* (rcx gets copied to r10 in the libc stub because the syscall
* instruction overwrites %cx) and are together in the trap frame
* with space following for 4 more entries.
*/
if (__predict_false(callp->sy_argsize > 6 * 8)) {
error = copyin((register_t *)frame->tf_rsp + 1,
&frame->tf_arg6, callp->sy_argsize - 6 * 8);
if (error != 0)
goto bad;
}
#else
if (callp->sy_argsize) {
error = x86_copyargs((char *)frame->tf_esp + sizeof(int), args,
callp->sy_argsize);
if (__predict_false(error != 0))
goto bad;
}
#endif
error = sy_invoke(callp, l, args, rval, code);
if (__predict_true(error == 0)) {
X86_TF_RAX(frame) = rval[0];
X86_TF_RDX(frame) = rval[1];
X86_TF_RFLAGS(frame) &= ~PSL_C; /* carry bit */
} else {
switch (error) {
case ERESTART:
/*
* The offset to adjust the PC by depends on whether we
* entered the kernel through the trap or call gate.
* We saved the instruction size in tf_err on entry.
*/
X86_TF_RIP(frame) -= frame->tf_err;
break;
case EJUSTRETURN:
/* nothing to do */
break;
default:
bad:
X86_TF_RAX(frame) = error;
X86_TF_RFLAGS(frame) |= PSL_C; /* carry bit */
break;
}
}
SYSCALL_TIME_SYS_EXIT(l);
userret(l);
}
void
syscall_intern(struct proc *p)
{
p->p_md.md_syscall = syscall;
}