stacktrace.cc revision 2235 
1/*
2 * Copyright (c) 2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * 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 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <string>
30
31#include "arch/alpha/isa_traits.hh"
32#include "arch/alpha/stacktrace.hh"
33#include "arch/alpha/vtophys.hh"
34#include "base/bitfield.hh"
35#include "base/trace.hh"
36#include "cpu/base.hh"
37#include "cpu/exec_context.hh"
38#include "sim/system.hh"
39
40using namespace std;
41using namespace AlphaISA;
42
43ProcessInfo::ProcessInfo(ExecContext *_xc)
44    : xc(_xc)
45{
46    Addr addr = 0;
47
48    if (!xc->getSystemPtr()->kernelSymtab->findAddress("thread_info_size", addr))
49        panic("thread info not compiled into kernel\n");
50    thread_info_size = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
51
52    if (!xc->getSystemPtr()->kernelSymtab->findAddress("task_struct_size", addr))
53        panic("thread info not compiled into kernel\n");
54    task_struct_size = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
55
56    if (!xc->getSystemPtr()->kernelSymtab->findAddress("thread_info_task", addr))
57        panic("thread info not compiled into kernel\n");
58    task_off = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
59
60    if (!xc->getSystemPtr()->kernelSymtab->findAddress("task_struct_pid", addr))
61        panic("thread info not compiled into kernel\n");
62    pid_off = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
63
64    if (!xc->getSystemPtr()->kernelSymtab->findAddress("task_struct_comm", addr))
65        panic("thread info not compiled into kernel\n");
66    name_off = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
67}
68
69Addr
70ProcessInfo::task(Addr ksp) const
71{
72    Addr base = ksp & ~0x3fff;
73    if (base == ULL(0xfffffc0000000000))
74        return 0;
75
76    Addr task;
77    CopyOut(xc, &task, base + task_off, sizeof(task));
78    return task;
79}
80
81int
82ProcessInfo::pid(Addr ksp) const
83{
84    Addr task = this->task(ksp);
85    if (!task)
86        return -1;
87
88    uint16_t pid;
89    CopyOut(xc, &pid, task + pid_off, sizeof(pid));
90    return pid;
91}
92
93string
94ProcessInfo::name(Addr ksp) const
95{
96    Addr task = this->task(ksp);
97    if (!task)
98        return "console";
99
100    char comm[256];
101    CopyString(xc, comm, task + name_off, sizeof(comm));
102    if (!comm[0])
103        return "startup";
104
105    return comm;
106}
107
108StackTrace::StackTrace()
109    : xc(0), stack(64)
110{
111}
112
113StackTrace::StackTrace(ExecContext *_xc, StaticInstPtr inst)
114    : xc(0), stack(64)
115{
116    trace(_xc, inst);
117}
118
119StackTrace::~StackTrace()
120{
121}
122
123void
124StackTrace::trace(ExecContext *_xc, bool is_call)
125{
126    xc = _xc;
127
128    bool usermode = (xc->readMiscReg(AlphaISA::IPR_DTB_CM) & 0x18) != 0;
129
130    Addr pc = xc->readNextPC();
131    bool kernel = xc->getSystemPtr()->kernelStart <= pc &&
132        pc <= xc->getSystemPtr()->kernelEnd;
133
134    if (usermode) {
135        stack.push_back(user);
136        return;
137    }
138
139    if (!kernel) {
140        stack.push_back(console);
141        return;
142    }
143
144    SymbolTable *symtab = xc->getSystemPtr()->kernelSymtab;
145    Addr ksp = xc->readIntReg(TheISA::StackPointerReg);
146    Addr bottom = ksp & ~0x3fff;
147    Addr addr;
148
149    if (is_call) {
150        if (!symtab->findNearestAddr(pc, addr))
151            panic("could not find address %#x", pc);
152
153        stack.push_back(addr);
154        pc = xc->readPC();
155    }
156
157    Addr ra;
158    int size;
159
160    while (ksp > bottom) {
161        if (!symtab->findNearestAddr(pc, addr))
162            panic("could not find symbol for pc=%#x", pc);
163        assert(pc >= addr && "symbol botch: callpc < func");
164
165        stack.push_back(addr);
166
167        if (isEntry(addr))
168            return;
169
170        if (decodePrologue(ksp, pc, addr, size, ra)) {
171            if (!ra)
172                return;
173
174            if (size <= 0) {
175                stack.push_back(unknown);
176                return;
177            }
178
179            pc = ra;
180            ksp += size;
181        } else {
182            stack.push_back(unknown);
183            return;
184        }
185
186        bool kernel = xc->getSystemPtr()->kernelStart <= pc &&
187            pc <= xc->getSystemPtr()->kernelEnd;
188        if (!kernel)
189            return;
190
191        if (stack.size() >= 1000)
192            panic("unwinding too far");
193    }
194
195    panic("unwinding too far");
196}
197
198bool
199StackTrace::isEntry(Addr addr)
200{
201    if (addr == xc->readMiscReg(AlphaISA::IPR_PALtemp12))
202        return true;
203
204    if (addr == xc->readMiscReg(AlphaISA::IPR_PALtemp7))
205        return true;
206
207    if (addr == xc->readMiscReg(AlphaISA::IPR_PALtemp11))
208        return true;
209
210    if (addr == xc->readMiscReg(AlphaISA::IPR_PALtemp21))
211        return true;
212
213    if (addr == xc->readMiscReg(AlphaISA::IPR_PALtemp9))
214        return true;
215
216    if (addr == xc->readMiscReg(AlphaISA::IPR_PALtemp2))
217        return true;
218
219    return false;
220}
221
222bool
223StackTrace::decodeStack(MachInst inst, int &disp)
224{
225    // lda $sp, -disp($sp)
226    //
227    // Opcode<31:26> == 0x08
228    // RA<25:21> == 30
229    // RB<20:16> == 30
230    // Disp<15:0>
231    const MachInst mem_mask = 0xffff0000;
232    const MachInst lda_pattern = 0x23de0000;
233    const MachInst lda_disp_mask = 0x0000ffff;
234
235    // subq $sp, disp, $sp
236    // addq $sp, disp, $sp
237    //
238    // Opcode<31:26> == 0x10
239    // RA<25:21> == 30
240    // Lit<20:13>
241    // One<12> = 1
242    // Func<11:5> == 0x20 (addq)
243    // Func<11:5> == 0x29 (subq)
244    // RC<4:0> == 30
245    const MachInst intop_mask = 0xffe01fff;
246    const MachInst addq_pattern = 0x43c0141e;
247    const MachInst subq_pattern = 0x43c0153e;
248    const MachInst intop_disp_mask = 0x001fe000;
249    const int intop_disp_shift = 13;
250
251    if ((inst & mem_mask) == lda_pattern)
252        disp = -sext<16>(inst & lda_disp_mask);
253    else if ((inst & intop_mask) == addq_pattern)
254        disp = -int((inst & intop_disp_mask) >> intop_disp_shift);
255    else if ((inst & intop_mask) == subq_pattern)
256        disp = int((inst & intop_disp_mask) >> intop_disp_shift);
257    else
258        return false;
259
260    return true;
261}
262
263bool
264StackTrace::decodeSave(MachInst inst, int &reg, int &disp)
265{
266    // lda $stq, disp($sp)
267    //
268    // Opcode<31:26> == 0x08
269    // RA<25:21> == ?
270    // RB<20:16> == 30
271    // Disp<15:0>
272    const MachInst stq_mask = 0xfc1f0000;
273    const MachInst stq_pattern = 0xb41e0000;
274    const MachInst stq_disp_mask = 0x0000ffff;
275    const MachInst reg_mask = 0x03e00000;
276    const int reg_shift = 21;
277
278    if ((inst & stq_mask) == stq_pattern) {
279        reg = (inst & reg_mask) >> reg_shift;
280        disp = sext<16>(inst & stq_disp_mask);
281    } else {
282        return false;
283    }
284
285    return true;
286}
287
288/*
289 * Decode the function prologue for the function we're in, and note
290 * which registers are stored where, and how large the stack frame is.
291 */
292bool
293StackTrace::decodePrologue(Addr sp, Addr callpc, Addr func,
294                           int &size, Addr &ra)
295{
296    size = 0;
297    ra = 0;
298
299    for (Addr pc = func; pc < callpc; pc += sizeof(MachInst)) {
300        MachInst inst;
301        CopyOut(xc, (uint8_t *)&inst, pc, sizeof(MachInst));
302
303        int reg, disp;
304        if (decodeStack(inst, disp)) {
305            if (size) {
306                // panic("decoding frame size again");
307                return true;
308            }
309            size += disp;
310        } else if (decodeSave(inst, reg, disp)) {
311            if (!ra && reg == ReturnAddressReg) {
312                CopyOut(xc, (uint8_t *)&ra, sp + disp, sizeof(Addr));
313                if (!ra) {
314                    // panic("no return address value pc=%#x\n", pc);
315                    return false;
316                }
317            }
318        }
319    }
320
321    return true;
322}
323
324#if TRACING_ON
325void
326StackTrace::dump()
327{
328    StringWrap name(xc->getCpuPtr()->name());
329    SymbolTable *symtab = xc->getSystemPtr()->kernelSymtab;
330
331    DPRINTFN("------ Stack ------\n");
332
333    string symbol;
334    for (int i = 0, size = stack.size(); i < size; ++i) {
335        Addr addr = stack[size - i - 1];
336        if (addr == user)
337            symbol = "user";
338        else if (addr == console)
339            symbol = "console";
340        else if (addr == unknown)
341            symbol = "unknown";
342        else
343            symtab->findSymbol(addr, symbol);
344
345        DPRINTFN("%#x: %s\n", addr, symbol);
346    }
347}
348#endif
349