stacktrace.cc revision 2107 
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
39using namespace std;
40using namespace AlphaISA;
41
42ProcessInfo::ProcessInfo(ExecContext *_xc)
43    : xc(_xc)
44{
45    Addr addr = 0;
46
47    if (!xc->system->kernelSymtab->findAddress("thread_info_size", addr))
48        panic("thread info not compiled into kernel\n");
49    thread_info_size = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
50
51    if (!xc->system->kernelSymtab->findAddress("task_struct_size", addr))
52        panic("thread info not compiled into kernel\n");
53    task_struct_size = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
54
55    if (!xc->system->kernelSymtab->findAddress("thread_info_task", addr))
56        panic("thread info not compiled into kernel\n");
57    task_off = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
58
59    if (!xc->system->kernelSymtab->findAddress("task_struct_pid", addr))
60        panic("thread info not compiled into kernel\n");
61    pid_off = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
62
63    if (!xc->system->kernelSymtab->findAddress("task_struct_comm", addr))
64        panic("thread info not compiled into kernel\n");
65    name_off = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
66}
67
68Addr
69ProcessInfo::task(Addr ksp) const
70{
71    Addr base = ksp & ~0x3fff;
72    if (base == ULL(0xfffffc0000000000))
73        return 0;
74
75    Addr task;
76    CopyOut(xc, &task, base + task_off, sizeof(task));
77    return task;
78}
79
80int
81ProcessInfo::pid(Addr ksp) const
82{
83    Addr task = this->task(ksp);
84    if (!task)
85        return -1;
86
87    uint16_t pid;
88    CopyOut(xc, &pid, task + pid_off, sizeof(pid));
89    return pid;
90}
91
92string
93ProcessInfo::name(Addr ksp) const
94{
95    Addr task = this->task(ksp);
96    if (!task)
97        return "console";
98
99    char comm[256];
100    CopyString(xc, comm, task + name_off, sizeof(comm));
101    if (!comm[0])
102        return "startup";
103
104    return comm;
105}
106
107StackTrace::StackTrace()
108    : xc(0), stack(64)
109{
110}
111
112StackTrace::StackTrace(ExecContext *_xc, StaticInstPtr inst)
113    : xc(0), stack(64)
114{
115    trace(_xc, inst);
116}
117
118StackTrace::~StackTrace()
119{
120}
121
122void
123StackTrace::trace(ExecContext *_xc, bool is_call)
124{
125    xc = _xc;
126
127    bool usermode = (xc->regs.ipr[AlphaISA::IPR_DTB_CM] & 0x18) != 0;
128
129    Addr pc = xc->regs.npc;
130    bool kernel = xc->system->kernelStart <= pc && pc <= xc->system->kernelEnd;
131
132    if (usermode) {
133        stack.push_back(user);
134        return;
135    }
136
137    if (!kernel) {
138        stack.push_back(console);
139        return;
140    }
141
142    SymbolTable *symtab = xc->system->kernelSymtab;
143    Addr ksp = xc->regs.intRegFile[TheISA::StackPointerReg];
144    Addr bottom = ksp & ~0x3fff;
145    Addr addr;
146
147    if (is_call) {
148        if (!symtab->findNearestAddr(pc, addr))
149            panic("could not find address %#x", pc);
150
151        stack.push_back(addr);
152        pc = xc->regs.pc;
153    }
154
155    Addr ra;
156    int size;
157
158    while (ksp > bottom) {
159        if (!symtab->findNearestAddr(pc, addr))
160            panic("could not find symbol for pc=%#x", pc);
161        assert(pc >= addr && "symbol botch: callpc < func");
162
163        stack.push_back(addr);
164
165        if (isEntry(addr))
166            return;
167
168        if (decodePrologue(ksp, pc, addr, size, ra)) {
169            if (!ra)
170                return;
171
172            if (size <= 0) {
173                stack.push_back(unknown);
174                return;
175            }
176
177            pc = ra;
178            ksp += size;
179        } else {
180            stack.push_back(unknown);
181            return;
182        }
183
184        bool kernel = xc->system->kernelStart <= pc &&
185            pc <= xc->system->kernelEnd;
186        if (!kernel)
187            return;
188
189        if (stack.size() >= 1000)
190            panic("unwinding too far");
191    }
192
193    panic("unwinding too far");
194}
195
196bool
197StackTrace::isEntry(Addr addr)
198{
199    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp12])
200        return true;
201
202    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp7])
203        return true;
204
205    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp11])
206        return true;
207
208    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp21])
209        return true;
210
211    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp9])
212        return true;
213
214    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp2])
215        return true;
216
217    return false;
218}
219
220bool
221StackTrace::decodeStack(MachInst inst, int &disp)
222{
223    // lda $sp, -disp($sp)
224    //
225    // Opcode<31:26> == 0x08
226    // RA<25:21> == 30
227    // RB<20:16> == 30
228    // Disp<15:0>
229    const MachInst mem_mask = 0xffff0000;
230    const MachInst lda_pattern = 0x23de0000;
231    const MachInst lda_disp_mask = 0x0000ffff;
232
233    // subq $sp, disp, $sp
234    // addq $sp, disp, $sp
235    //
236    // Opcode<31:26> == 0x10
237    // RA<25:21> == 30
238    // Lit<20:13>
239    // One<12> = 1
240    // Func<11:5> == 0x20 (addq)
241    // Func<11:5> == 0x29 (subq)
242    // RC<4:0> == 30
243    const MachInst intop_mask = 0xffe01fff;
244    const MachInst addq_pattern = 0x43c0141e;
245    const MachInst subq_pattern = 0x43c0153e;
246    const MachInst intop_disp_mask = 0x001fe000;
247    const int intop_disp_shift = 13;
248
249    if ((inst & mem_mask) == lda_pattern)
250        disp = -sext<16>(inst & lda_disp_mask);
251    else if ((inst & intop_mask) == addq_pattern)
252        disp = -int((inst & intop_disp_mask) >> intop_disp_shift);
253    else if ((inst & intop_mask) == subq_pattern)
254        disp = int((inst & intop_disp_mask) >> intop_disp_shift);
255    else
256        return false;
257
258    return true;
259}
260
261bool
262StackTrace::decodeSave(MachInst inst, int &reg, int &disp)
263{
264    // lda $stq, disp($sp)
265    //
266    // Opcode<31:26> == 0x08
267    // RA<25:21> == ?
268    // RB<20:16> == 30
269    // Disp<15:0>
270    const MachInst stq_mask = 0xfc1f0000;
271    const MachInst stq_pattern = 0xb41e0000;
272    const MachInst stq_disp_mask = 0x0000ffff;
273    const MachInst reg_mask = 0x03e00000;
274    const int reg_shift = 21;
275
276    if ((inst & stq_mask) == stq_pattern) {
277        reg = (inst & reg_mask) >> reg_shift;
278        disp = sext<16>(inst & stq_disp_mask);
279    } else {
280        return false;
281    }
282
283    return true;
284}
285
286/*
287 * Decode the function prologue for the function we're in, and note
288 * which registers are stored where, and how large the stack frame is.
289 */
290bool
291StackTrace::decodePrologue(Addr sp, Addr callpc, Addr func,
292                           int &size, Addr &ra)
293{
294    size = 0;
295    ra = 0;
296
297    for (Addr pc = func; pc < callpc; pc += sizeof(MachInst)) {
298        MachInst inst;
299        CopyOut(xc, (uint8_t *)&inst, pc, sizeof(MachInst));
300
301        int reg, disp;
302        if (decodeStack(inst, disp)) {
303            if (size) {
304                // panic("decoding frame size again");
305                return true;
306            }
307            size += disp;
308        } else if (decodeSave(inst, reg, disp)) {
309            if (!ra && reg == ReturnAddressReg) {
310                CopyOut(xc, (uint8_t *)&ra, sp + disp, sizeof(Addr));
311                if (!ra) {
312                    // panic("no return address value pc=%#x\n", pc);
313                    return false;
314                }
315            }
316        }
317    }
318
319    return true;
320}
321
322#if TRACING_ON
323void
324StackTrace::dump()
325{
326    StringWrap name(xc->cpu->name());
327    SymbolTable *symtab = xc->system->kernelSymtab;
328
329    DPRINTFN("------ Stack ------\n");
330
331    string symbol;
332    for (int i = 0, size = stack.size(); i < size; ++i) {
333        Addr addr = stack[size - i - 1];
334        if (addr == user)
335            symbol = "user";
336        else if (addr == console)
337            symbol = "console";
338        else if (addr == unknown)
339            symbol = "unknown";
340        else
341            symtab->findSymbol(addr, symbol);
342
343        DPRINTFN("%#x: %s\n", addr, symbol);
344    }
345}
346#endif
347