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/*
* Copyright (c) 2003 Russell King <rmk@arm.linux.org.uk>
* Copyright (c) 2011-2013 Denys Vlasenko <vda.linux@googlemail.com>
* Copyright (c) 2011-2015 Dmitry V. Levin <ldv@altlinux.org>
* Copyright (c) 2015-2018 The strace developers.
* All rights reserved.
*
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/* Return codes: 1 - ok, 0 - ignore, other - error. */
static int
arch_get_scno(struct tcb *tcp)
{
kernel_ulong_t scno = 0;
/* Note: we support only 32-bit CPUs, not 26-bit */
#if !defined(__ARM_EABI__) || ENABLE_ARM_OABI
if (arm_regs.ARM_cpsr & 0x20) {
/* Thumb mode */
goto scno_in_r7;
}
/* ARM mode */
/* Check EABI/OABI by examining SVC insn's low 24 bits */
errno = 0;
scno = ptrace(PTRACE_PEEKTEXT, tcp->pid, (void *)(arm_regs.ARM_pc - 4), NULL);
if (errno)
return -1;
/* EABI syscall convention? */
if (scno != 0xef000000) {
/* No, it's OABI */
if ((scno & 0x0ff00000) != 0x0f900000) {
error_msg("pid %d unknown syscall trap 0x%08lx",
tcp->pid, scno);
return -1;
}
/* Fixup the syscall number */
scno &= 0x000fffff;
} else {
scno_in_r7:
scno = arm_regs.ARM_r7;
}
#else /* __ARM_EABI__ || !ENABLE_ARM_OABI */
scno = arm_regs.ARM_r7;
#endif
/*
* Do some sanity checks to figure out
* whether it's really a syscall entry.
*/
if (arm_regs.ARM_ip && !scno_in_range(scno)) {
debug_msg("pid %d stray syscall exit: ARM_ip = %ld, scno = %ld",
tcp->pid, arm_regs.ARM_ip, scno);
return 0;
}
tcp->scno = scno;
return 1;
}