arm-freebsd.c revision 331722 
1/*
2 * Copyright 1997 Sean Eric Fagan
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 * 3. All advertising materials mentioning features or use of this software
13 *    must display the following acknowledgement:
14 *	This product includes software developed by Sean Eric Fagan
15 * 4. Neither the name of the author may be used to endorse or promote
16 *    products derived from this software without specific prior written
17 *    permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: stable/11/usr.bin/truss/arm-freebsd.c 331722 2018-03-29 02:50:57Z eadler $");
34
35/* FreeBSD/arm-specific system call handling. */
36
37#include <sys/ptrace.h>
38#include <sys/syscall.h>
39
40#include <machine/reg.h>
41#include <machine/armreg.h>
42#include <machine/ucontext.h>
43
44#include <stdbool.h>
45#include <stdio.h>
46#include <sysdecode.h>
47
48#include "truss.h"
49
50static int
51arm_fetch_args(struct trussinfo *trussinfo, u_int narg)
52{
53	struct ptrace_io_desc iorequest;
54	struct reg regs;
55	struct current_syscall *cs;
56	lwpid_t tid;
57	u_int i, reg, syscall_num;
58
59	tid = trussinfo->curthread->tid;
60	cs = &trussinfo->curthread->cs;
61	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
62		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
63		return (-1);
64	}
65
66	/*
67	 * FreeBSD has two special kinds of system call redirections --
68	 * SYS_syscall, and SYS___syscall.  The former is the old syscall()
69	 * routine, basically; the latter is for quad-aligned arguments.
70	 *
71	 * The system call argument count and code from ptrace() already
72	 * account for these, but we need to skip over the first argument.
73	 */
74#ifdef __ARM_EABI__
75	syscall_num = regs.r[7];
76#else
77	if ((syscall_num = ptrace(PT_READ_I, tid,
78	    (caddr_t)(regs.r[_REG_PC] - INSN_SIZE), 0)) == -1) {
79		fprintf(trussinfo->outfile, "-- CANNOT READ PC --\n");
80		return (-1);
81	}
82	syscall_num = syscall_num & 0x000fffff;
83#endif
84
85	reg = 0;
86	switch (syscall_num) {
87	case SYS_syscall:
88		reg = 1;
89		break;
90	case SYS___syscall:
91		reg = 2;
92		break;
93	}
94
95	for (i = 0; i < narg && reg < 4; i++, reg++)
96		cs->args[i] = regs.r[reg];
97	if (narg > i) {
98		iorequest.piod_op = PIOD_READ_D;
99		iorequest.piod_offs = (void *)(regs.r_sp +
100		    4 * sizeof(uint32_t));
101		iorequest.piod_addr = &cs->args[i];
102		iorequest.piod_len = (narg - i) * sizeof(cs->args[0]);
103		ptrace(PT_IO, tid, (caddr_t)&iorequest, 0);
104		if (iorequest.piod_len == 0)
105			return (-1);
106	}
107
108	return (0);
109}
110
111static int
112arm_fetch_retval(struct trussinfo *trussinfo, long *retval, int *errorp)
113{
114	struct reg regs;
115	lwpid_t tid;
116
117	tid = trussinfo->curthread->tid;
118	if (ptrace(PT_GETREGS, tid, (caddr_t)&regs, 0) < 0) {
119		fprintf(trussinfo->outfile, "-- CANNOT READ REGISTERS --\n");
120		return (-1);
121	}
122
123	/* XXX: Does not have the __ARMEB__ handling for __syscall(). */
124	retval[0] = regs.r[0];
125	retval[1] = regs.r[1];
126	*errorp = !!(regs.r_cpsr & PSR_C);
127	return (0);
128}
129
130static struct procabi arm_freebsd = {
131	"FreeBSD ELF32",
132	SYSDECODE_ABI_FREEBSD,
133	arm_fetch_args,
134	arm_fetch_retval,
135	STAILQ_HEAD_INITIALIZER(arm_freebsd.extra_syscalls),
136	{ NULL }
137};
138
139PROCABI(arm_freebsd);
140