1/*
2 * Copyright 2018 Google, Inc.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met: redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer;
8 * redistributions in binary form must reproduce the above copyright
9 * notice, this list of conditions and the following disclaimer in the
10 * documentation and/or other materials provided with the distribution;
11 * neither the name of the copyright holders nor the names of its
12 * contributors may be used to endorse or promote products derived from
13 * this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 * Authors: Gabe Black
28 */
29
30#include "base/fiber.hh"
31
| 1/*
2 * Copyright 2018 Google, Inc.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met: redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer;
8 * redistributions in binary form must reproduce the above copyright
9 * notice, this list of conditions and the following disclaimer in the
10 * documentation and/or other materials provided with the distribution;
11 * neither the name of the copyright holders nor the names of its
12 * contributors may be used to endorse or promote products derived from
13 * this software without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
18 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
19 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
21 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 * Authors: Gabe Black
28 */
29
30#include "base/fiber.hh"
31
|
| 32#if HAVE_VALGRIND
33#include <valgrind/valgrind.h>
34#endif
35
|
32#include <cerrno>
33#include <cstring>
34
35#include "base/logging.hh"
36
37using namespace std;
38
39namespace
40{
41
42/*
43 * The PrimaryFiber class is a special case that attaches to the currently
44 * executing context. That makes handling the "primary" fiber, aka the one
45 * which most of gem5 is running under, no different than other Fibers.
46 */
47class PrimaryFiber : public Fiber
48{
49 public:
50 PrimaryFiber() : Fiber(nullptr, 0) { setStarted(); }
51 void main() { panic("PrimaryFiber main executed.\n"); }
52};
53
54PrimaryFiber _primaryFiber;
55
56// A pointer to whatever the currently executing Fiber is.
57Fiber *_currentFiber = &_primaryFiber;
58
59// A pointer to the Fiber which is currently being started/initialized.
60Fiber *startingFiber = nullptr;
61
62} // anonymous namespace
63
64void
65Fiber::entryTrampoline()
66{
67 startingFiber->start();
68}
69
70Fiber::Fiber(size_t stack_size) :
71 link(primaryFiber()),
72 stack(stack_size ? new uint8_t[stack_size] : nullptr),
73 stackSize(stack_size), started(false), _finished(false)
| 36#include <cerrno>
37#include <cstring>
38
39#include "base/logging.hh"
40
41using namespace std;
42
43namespace
44{
45
46/*
47 * The PrimaryFiber class is a special case that attaches to the currently
48 * executing context. That makes handling the "primary" fiber, aka the one
49 * which most of gem5 is running under, no different than other Fibers.
50 */
51class PrimaryFiber : public Fiber
52{
53 public:
54 PrimaryFiber() : Fiber(nullptr, 0) { setStarted(); }
55 void main() { panic("PrimaryFiber main executed.\n"); }
56};
57
58PrimaryFiber _primaryFiber;
59
60// A pointer to whatever the currently executing Fiber is.
61Fiber *_currentFiber = &_primaryFiber;
62
63// A pointer to the Fiber which is currently being started/initialized.
64Fiber *startingFiber = nullptr;
65
66} // anonymous namespace
67
68void
69Fiber::entryTrampoline()
70{
71 startingFiber->start();
72}
73
74Fiber::Fiber(size_t stack_size) :
75 link(primaryFiber()),
76 stack(stack_size ? new uint8_t[stack_size] : nullptr),
77 stackSize(stack_size), started(false), _finished(false)
|
74{}
| 78{
79#if HAVE_VALGRIND
80 valgrindStackId = VALGRIND_STACK_REGISTER(stack, stack + stack_size);
81#endif
82}
|
75
76Fiber::Fiber(Fiber *link, size_t stack_size) :
77 link(link), stack(stack_size ? new uint8_t[stack_size] : nullptr),
78 stackSize(stack_size), started(false), _finished(false)
79{}
80
81Fiber::~Fiber()
82{
83 panic_if(stack && _currentFiber == this, "Fiber stack is in use.");
| 83
84Fiber::Fiber(Fiber *link, size_t stack_size) :
85 link(link), stack(stack_size ? new uint8_t[stack_size] : nullptr),
86 stackSize(stack_size), started(false), _finished(false)
87{}
88
89Fiber::~Fiber()
90{
91 panic_if(stack && _currentFiber == this, "Fiber stack is in use.");
|
| 92#if HAVE_VALGRIND
93 VALGRIND_STACK_DEREGISTER(valgrindStackId);
94#endif
|
84 delete [] stack;
85}
86
87void
88Fiber::createContext()
89{
90 // Set up a context for the new fiber, starting it in the trampoline.
91 getcontext(&ctx);
92 ctx.uc_stack.ss_sp = stack;
93 ctx.uc_stack.ss_size = stackSize;
94 ctx.uc_link = nullptr;
95 makecontext(&ctx, &entryTrampoline, 0);
96
97 // Swap to the new context so it can enter its start() function. It
98 // will then swap itself back out and return here.
99 startingFiber = this;
100 panic_if(!_currentFiber, "No active Fiber object.");
101 swapcontext(&_currentFiber->ctx, &ctx);
102
103 // The new context is now ready and about to call main().
104}
105
106void
107Fiber::start()
108{
109 // Avoid a dangling pointer.
110 startingFiber = nullptr;
111
112 setStarted();
113
114 // Swap back to the parent context which is still considered "current",
115 // now that we're ready to go.
116 int ret M5_VAR_USED = swapcontext(&ctx, &_currentFiber->ctx);
117 panic_if(ret == -1, strerror(errno));
118
119 // Call main() when we're been reactivated for the first time.
120 main();
121
122 // main has returned, so this Fiber has finished. Switch to the "link"
123 // Fiber.
124 _finished = true;
125 link->run();
126}
127
128void
129Fiber::run()
130{
131 panic_if(_finished, "Fiber has already run to completion.");
132
133 // If we're already running this fiber, we're done.
134 if (_currentFiber == this)
135 return;
136
137 if (!started)
138 createContext();
139
140 // Switch out of the current Fiber's context and this one's in.
141 Fiber *prev = _currentFiber;
142 Fiber *next = this;
143 _currentFiber = next;
144 swapcontext(&prev->ctx, &next->ctx);
145}
146
147Fiber *Fiber::currentFiber() { return _currentFiber; }
148Fiber *Fiber::primaryFiber() { return &_primaryFiber; }
| 95 delete [] stack;
96}
97
98void
99Fiber::createContext()
100{
101 // Set up a context for the new fiber, starting it in the trampoline.
102 getcontext(&ctx);
103 ctx.uc_stack.ss_sp = stack;
104 ctx.uc_stack.ss_size = stackSize;
105 ctx.uc_link = nullptr;
106 makecontext(&ctx, &entryTrampoline, 0);
107
108 // Swap to the new context so it can enter its start() function. It
109 // will then swap itself back out and return here.
110 startingFiber = this;
111 panic_if(!_currentFiber, "No active Fiber object.");
112 swapcontext(&_currentFiber->ctx, &ctx);
113
114 // The new context is now ready and about to call main().
115}
116
117void
118Fiber::start()
119{
120 // Avoid a dangling pointer.
121 startingFiber = nullptr;
122
123 setStarted();
124
125 // Swap back to the parent context which is still considered "current",
126 // now that we're ready to go.
127 int ret M5_VAR_USED = swapcontext(&ctx, &_currentFiber->ctx);
128 panic_if(ret == -1, strerror(errno));
129
130 // Call main() when we're been reactivated for the first time.
131 main();
132
133 // main has returned, so this Fiber has finished. Switch to the "link"
134 // Fiber.
135 _finished = true;
136 link->run();
137}
138
139void
140Fiber::run()
141{
142 panic_if(_finished, "Fiber has already run to completion.");
143
144 // If we're already running this fiber, we're done.
145 if (_currentFiber == this)
146 return;
147
148 if (!started)
149 createContext();
150
151 // Switch out of the current Fiber's context and this one's in.
152 Fiber *prev = _currentFiber;
153 Fiber *next = this;
154 _currentFiber = next;
155 swapcontext(&prev->ctx, &next->ctx);
156}
157
158Fiber *Fiber::currentFiber() { return _currentFiber; }
159Fiber *Fiber::primaryFiber() { return &_primaryFiber; }
|