syscall_desc.cc revision 11877 
1/*
2 * Copyright (c) 2016 Advanced Micro Devices, Inc.
3 * Copyright (c) 2003-2005 The Regents of The University of Michigan
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * 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
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * Authors: Steve Reinhardt
30 *          Ali Saidi
31 *          Brandon Potter
32 */
33
34#include "sim/syscall_desc.hh"
35
36#include <memory>
37
38#include "base/trace.hh"
39#include "base/types.hh"
40#include "config/the_isa.hh"
41#include "cpu/base.hh"
42#include "cpu/thread_context.hh"
43#include "sim/faults.hh"
44#include "sim/process.hh"
45#include "sim/syscall_debug_macros.hh"
46#include "sim/syscall_return.hh"
47
48void
49SyscallDesc::doSyscall(int callnum, Process *process, ThreadContext *tc,
50                       Fault *fault)
51{
52    TheISA::IntReg arg[6] M5_VAR_USED;
53
54    /**
55     * Step through the first six parameters for the system call and
56     * retrieve their values. Note that index is incremented as a
57     * side-effect of the getSyscallArg method which is why the LHS
58     * needs the "-1".
59     */
60    for (int index = 0; index < 6; )
61        arg[index - 1] = process->getSyscallArg(tc, index);
62
63    /**
64     * Linux supports up to six system call arguments through registers
65     * so we want to print all six. Check to the relevant man page to
66     * verify how many are actually used by a given system call.
67     */
68    DPRINTF_SYSCALL(Base, "%s called w/arguments %d, %d, %d, %d, %d, %d\n",
69                    _name, arg[0], arg[1], arg[2], arg[3], arg[4], arg[5]);
70
71    /** Invoke the system call */
72    SyscallReturn retval = (*executor)(this, callnum, process, tc);
73
74    /**
75     * If the system call needs to be restarted, most likely due to
76     * blocking behavior, warn that the system call will retry;
77     * alternatively, print the return value.
78     */
79    if (retval.needsRetry()) {
80        *fault = std::make_shared<SyscallRetryFault>();
81        DPRINTF_SYSCALL(Base, "%s needs retry\n", _name);
82    } else
83        DPRINTF_SYSCALL(Base, "%s returns %d\n", _name, retval.encodedValue());
84
85    if (!(_flags & SyscallDesc::SuppressReturnValue) && !retval.needsRetry())
86        process->setSyscallReturn(tc, retval);
87}
88
89bool
90SyscallDesc::needWarning()
91{
92    bool suppress_warning = warnOnce() && _warned;
93    _warned = true;
94    return !suppress_warning;
95}
96