1 /* $NetBSD: freebsd_syscall.c,v 1.7 2023/10/05 19:41:06 ad Exp $ */
2
3 /*-
4 * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Charles M. Hannum.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 __KERNEL_RCSID(0, "$NetBSD: freebsd_syscall.c,v 1.7 2023/10/05 19:41:06 ad Exp $");
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/proc.h>
38 #include <sys/signal.h>
39 #include <sys/syscall.h>
40 #include <sys/syscallvar.h>
41
42 #include <uvm/uvm_extern.h>
43
44 #include <machine/cpu.h>
45 #include <machine/psl.h>
46 #include <machine/userret.h>
47
48 #include <compat/sys/signal.h>
49
50 #include <compat/freebsd/freebsd_machdep.h>
51 #include <compat/freebsd/freebsd_syscall.h>
52
53 void freebsd_syscall(struct trapframe *);
54
55 void
freebsd_syscall_intern(struct proc * p)56 freebsd_syscall_intern(struct proc *p)
57 {
58
59 p->p_md.md_syscall = freebsd_syscall;
60 }
61
62 /*
63 * syscall(frame):
64 * System call request from POSIX system call gate interface to kernel.
65 * Like trap(), argument is call by reference.
66 */
67 void
freebsd_syscall(struct trapframe * frame)68 freebsd_syscall(struct trapframe *frame)
69 {
70 char *params;
71 const struct sysent *callp;
72 struct lwp *l;
73 struct proc *p;
74 int error;
75 size_t argsize;
76 register_t code, args[8], rval[2];
77
78 l = curlwp;
79 p = l->l_proc;
80
81 code = frame->tf_eax;
82 callp = p->p_emul->e_sysent;
83 params = (char *)frame->tf_esp + sizeof(int);
84
85 switch (code) {
86 case SYS_syscall:
87 /*
88 * Code is first argument, followed by actual args.
89 */
90 error = ufetch_long((void *)params, (u_long *)&code);
91 if (error)
92 goto bad;
93 params += sizeof(int);
94 break;
95 case SYS___syscall:
96 /*
97 * Like syscall, but code is a quad, so as to maintain
98 * quad alignment for the rest of the arguments.
99 */
100 error = ufetch_long((void *)(params +
101 _QUAD_LOWWORD * sizeof(int)),
102 (u_long *)&code);
103 if (error)
104 goto bad;
105 params += sizeof(quad_t);
106 break;
107 default:
108 break;
109 }
110
111 code &= (SYS_NSYSENT - 1);
112 callp += code;
113 argsize = callp->sy_argsize;
114 if (argsize) {
115 error = copyin(params, (void *)args, argsize);
116 if (error)
117 goto bad;
118 }
119
120 if (!__predict_false(p->p_trace_enabled || KDTRACE_ENTRY(callp->sy_entry))
121 || (error = trace_enter(code, callp, args)) == 0) {
122 rval[0] = 0;
123 rval[1] = frame->tf_edx; /* need to keep edx for shared FreeBSD bins */
124 error = sy_call(callp, l, args, rval);
125 }
126
127 switch (error) {
128 case 0:
129 frame->tf_eax = rval[0];
130 frame->tf_edx = rval[1];
131 frame->tf_eflags &= ~PSL_C; /* carry bit */
132 break;
133 case ERESTART:
134 /*
135 * The offset to adjust the PC by depends on whether we entered
136 * the kernel through the trap or call gate. We pushed the
137 * size of the instruction into tf_err on entry.
138 */
139 frame->tf_eip -= frame->tf_err;
140 break;
141 case EJUSTRETURN:
142 /* nothing to do */
143 break;
144 default:
145 bad:
146 frame->tf_eax = error;
147 frame->tf_eflags |= PSL_C; /* carry bit */
148 break;
149 }
150
151 if (__predict_false(p->p_trace_enabled || KDTRACE_ENTRY(callp->sy_return)))
152 trace_exit(code, callp, args, rval, error);
153
154 userret(l);
155 }
156