1 /*
2 * Copyright (c) 2003 Russell King <rmk@arm.linux.org.uk>
3 * Copyright (c) 2011-2013 Denys Vlasenko <vda.linux@googlemail.com>
4 * Copyright (c) 2011-2015 Dmitry V. Levin <ldv@altlinux.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 /* Return codes: 1 - ok, 0 - ignore, other - error. */
31 static int
arch_get_scno(struct tcb * tcp)32 arch_get_scno(struct tcb *tcp)
33 {
34 long scno = 0;
35
36 /* Note: we support only 32-bit CPUs, not 26-bit */
37
38 #if !defined(__ARM_EABI__) || ENABLE_ARM_OABI
39 if (arm_regs.ARM_cpsr & 0x20) {
40 /* Thumb mode */
41 goto scno_in_r7;
42 }
43 /* ARM mode */
44 /* Check EABI/OABI by examining SVC insn's low 24 bits */
45 errno = 0;
46 scno = ptrace(PTRACE_PEEKTEXT, tcp->pid, (void *)(arm_regs.ARM_pc - 4), NULL);
47 if (errno)
48 return -1;
49 /* EABI syscall convention? */
50 if ((unsigned long) scno != 0xef000000) {
51 /* No, it's OABI */
52 if ((scno & 0x0ff00000) != 0x0f900000) {
53 error_msg("pid %d unknown syscall trap 0x%08lx",
54 tcp->pid, scno);
55 return -1;
56 }
57 /* Fixup the syscall number */
58 scno &= 0x000fffff;
59 } else {
60 scno_in_r7:
61 scno = arm_regs.ARM_r7;
62 }
63 #else /* __ARM_EABI__ || !ENABLE_ARM_OABI */
64
65 scno = arm_regs.ARM_r7;
66
67 #endif
68
69 scno = shuffle_scno(scno);
70
71 /*
72 * Do some sanity checks to figure out
73 * whether it's really a syscall entry.
74 */
75 if (arm_regs.ARM_ip && !SCNO_IN_RANGE(scno)) {
76 if (debug_flag)
77 error_msg("pid %d stray syscall exit:"
78 " ARM_ip = %ld, scno = %ld",
79 tcp->pid, arm_regs.ARM_ip,
80 shuffle_scno(scno));
81 return 0;
82 }
83
84 tcp->scno = scno;
85 return 1;
86 }
87