arm-freebsd.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-4-Clause
3 *
4 * Copyright 1997 Sean Eric Fagan
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgement:
16 *	This product includes software developed by Sean Eric Fagan
17 * 4. Neither the name of the author may be used to endorse or promote
18 *    products derived from this software without specific prior written
19 *    permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: stable/11/usr.bin/truss/arm-freebsd.c 330897 2018-03-14 03:19:51Z eadler $");
36
37/* FreeBSD/arm-specific system call handling. */
38
39#include <sys/ptrace.h>
40#include <sys/syscall.h>
41
42#include <machine/reg.h>
43#include <machine/armreg.h>
44#include <machine/ucontext.h>
45
46#include <stdbool.h>
47#include <stdio.h>
48#include <sysdecode.h>
49
50#include "truss.h"
51
52static int
53arm_fetch_args(struct trussinfo *trussinfo, u_int narg)
54{
55	struct ptrace_io_desc iorequest;
56	struct reg regs;
57	struct current_syscall *cs;
58	lwpid_t tid;
59	u_int i, reg, syscall_num;
60
61	tid = trussinfo->curthread->tid;
62	cs = &trussinfo->curthread->cs;
63	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
64		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
65		return (-1);
66	}
67
68	/*
69	 * FreeBSD has two special kinds of system call redirections --
70	 * SYS_syscall, and SYS___syscall.  The former is the old syscall()
71	 * routine, basically; the latter is for quad-aligned arguments.
72	 *
73	 * The system call argument count and code from ptrace() already
74	 * account for these, but we need to skip over the first argument.
75	 */
76#ifdef __ARM_EABI__
77	syscall_num = regs.r[7];
78#else
79	if ((syscall_num = ptrace(PT_READ_I, tid,
80	    (caddr_t)(regs.r[_REG_PC] - INSN_SIZE), 0)) == -1) {
81		fprintf(trussinfo->outfile, "-- CANNOT READ PC --\n");
82		return (-1);
83	}
84	syscall_num = syscall_num & 0x000fffff;
85#endif
86
87	reg = 0;
88	switch (syscall_num) {
89	case SYS_syscall:
90		reg = 1;
91		break;
92	case SYS___syscall:
93		reg = 2;
94		break;
95	}
96
97	for (i = 0; i < narg && reg < 4; i++, reg++)
98		cs->args[i] = regs.r[reg];
99	if (narg > i) {
100		iorequest.piod_op = PIOD_READ_D;
101		iorequest.piod_offs = (void *)(regs.r_sp +
102		    4 * sizeof(uint32_t));
103		iorequest.piod_addr = &cs->args[i];
104		iorequest.piod_len = (narg - i) * sizeof(cs->args[0]);
105		ptrace(PT_IO, tid, (caddr_t)&iorequest, 0);
106		if (iorequest.piod_len == 0)
107			return (-1);
108	}
109
110	return (0);
111}
112
113static int
114arm_fetch_retval(struct trussinfo *trussinfo, long *retval, int *errorp)
115{
116	struct reg regs;
117	lwpid_t tid;
118
119	tid = trussinfo->curthread->tid;
120	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
121		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
122		return (-1);
123	}
124
125	/* XXX: Does not have the __ARMEB__ handling for __syscall(). */
126	retval[0] = regs.r[0];
127	retval[1] = regs.r[1];
128	*errorp = !!(regs.r_cpsr & PSR_C);
129	return (0);
130}
131
132static struct procabi arm_freebsd = {
133	"FreeBSD ELF32",
134	SYSDECODE_ABI_FREEBSD,
135	arm_fetch_args,
136	arm_fetch_retval,
137	STAILQ_HEAD_INITIALIZER(arm_freebsd.extra_syscalls),
138	{ NULL }
139};
140
141PROCABI(arm_freebsd);
142