stacktrace.cc revision 1977 
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;
40
41ProcessInfo::ProcessInfo(ExecContext *_xc)
42    : xc(_xc)
43{
44    Addr addr = 0;
45
46    if (!xc->system->kernelSymtab->findAddress("thread_info_size", addr))
47        panic("thread info not compiled into kernel\n");
48    thread_info_size = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
49
50    if (!xc->system->kernelSymtab->findAddress("task_struct_size", addr))
51        panic("thread info not compiled into kernel\n");
52    task_struct_size = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
53
54    if (!xc->system->kernelSymtab->findAddress("thread_info_task", addr))
55        panic("thread info not compiled into kernel\n");
56    task_off = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
57
58    if (!xc->system->kernelSymtab->findAddress("task_struct_pid", addr))
59        panic("thread info not compiled into kernel\n");
60    pid_off = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
61
62    if (!xc->system->kernelSymtab->findAddress("task_struct_comm", addr))
63        panic("thread info not compiled into kernel\n");
64    name_off = *(int32_t *)vtomem(xc, addr, sizeof(int32_t));
65}
66
67Addr
68ProcessInfo::task(Addr ksp) const
69{
70    Addr base = ksp & ~0x3fff;
71    if (base == ULL(0xfffffc0000000000))
72        return 0;
73
74    Addr task;
75    CopyOut(xc, &task, base + task_off, sizeof(task));
76    return task;
77}
78
79int
80ProcessInfo::pid(Addr ksp) const
81{
82    Addr task = this->task(ksp);
83    if (!task)
84        return -1;
85
86    uint16_t pid;
87    CopyOut(xc, &pid, task + pid_off, sizeof(pid));
88    return pid;
89}
90
91string
92ProcessInfo::name(Addr ksp) const
93{
94    Addr task = this->task(ksp);
95    if (!task)
96        return "console";
97
98    char comm[256];
99    CopyString(xc, comm, task + name_off, sizeof(comm));
100    if (!comm[0])
101        return "startup";
102
103    return comm;
104}
105
106StackTrace::StackTrace()
107    : xc(0), stack(64)
108{
109}
110
111StackTrace::StackTrace(ExecContext *_xc, StaticInstPtr<TheISA> inst)
112    : xc(0), stack(64)
113{
114    trace(_xc, inst);
115}
116
117StackTrace::~StackTrace()
118{
119}
120
121void
122StackTrace::trace(ExecContext *_xc, bool is_call)
123{
124    xc = _xc;
125
126    bool usermode = (xc->regs.ipr[AlphaISA::IPR_DTB_CM] & 0x18) != 0;
127
128    Addr pc = xc->regs.npc;
129    bool kernel = xc->system->kernelStart <= pc && pc <= xc->system->kernelEnd;
130
131    if (usermode) {
132        stack.push_back(user);
133        return;
134    }
135
136    if (!kernel) {
137        stack.push_back(console);
138        return;
139    }
140
141    SymbolTable *symtab = xc->system->kernelSymtab;
142    Addr ksp = xc->regs.intRegFile[TheISA::StackPointerReg];
143    Addr bottom = ksp & ~0x3fff;
144    Addr addr;
145
146    if (is_call) {
147        if (!symtab->findNearestAddr(pc, addr))
148            panic("could not find address %#x", pc);
149
150        stack.push_back(addr);
151        pc = xc->regs.pc;
152    }
153
154    Addr ra;
155    int size;
156
157    while (ksp > bottom) {
158        if (!symtab->findNearestAddr(pc, addr))
159            panic("could not find symbol for pc=%#x", pc);
160        assert(pc >= addr && "symbol botch: callpc < func");
161
162        stack.push_back(addr);
163
164        if (isEntry(addr))
165            return;
166
167        if (decodePrologue(ksp, pc, addr, size, ra)) {
168            if (!ra)
169                return;
170
171            if (size <= 0) {
172                stack.push_back(unknown);
173                return;
174            }
175
176            pc = ra;
177            ksp += size;
178        } else {
179            stack.push_back(unknown);
180            return;
181        }
182
183        bool kernel = xc->system->kernelStart <= pc &&
184            pc <= xc->system->kernelEnd;
185        if (!kernel)
186            return;
187
188        if (stack.size() >= 1000)
189            panic("unwinding too far");
190    }
191
192    panic("unwinding too far");
193}
194
195bool
196StackTrace::isEntry(Addr addr)
197{
198    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp12])
199        return true;
200
201    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp7])
202        return true;
203
204    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp11])
205        return true;
206
207    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp21])
208        return true;
209
210    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp9])
211        return true;
212
213    if (addr == xc->regs.ipr[AlphaISA::IPR_PALtemp2])
214        return true;
215
216    return false;
217}
218
219bool
220StackTrace::decodeStack(MachInst inst, int &disp)
221{
222    // lda $sp, -disp($sp)
223    //
224    // Opcode<31:26> == 0x08
225    // RA<25:21> == 30
226    // RB<20:16> == 30
227    // Disp<15:0>
228    const MachInst mem_mask = 0xffff0000;
229    const MachInst lda_pattern = 0x23de0000;
230    const MachInst lda_disp_mask = 0x0000ffff;
231
232    // subq $sp, disp, $sp
233    // addq $sp, disp, $sp
234    //
235    // Opcode<31:26> == 0x10
236    // RA<25:21> == 30
237    // Lit<20:13>
238    // One<12> = 1
239    // Func<11:5> == 0x20 (addq)
240    // Func<11:5> == 0x29 (subq)
241    // RC<4:0> == 30
242    const MachInst intop_mask = 0xffe01fff;
243    const MachInst addq_pattern = 0x43c0141e;
244    const MachInst subq_pattern = 0x43c0153e;
245    const MachInst intop_disp_mask = 0x001fe000;
246    const int intop_disp_shift = 13;
247
248    if ((inst & mem_mask) == lda_pattern)
249        disp = -sext<16>(inst & lda_disp_mask);
250    else if ((inst & intop_mask) == addq_pattern)
251        disp = -int((inst & intop_disp_mask) >> intop_disp_shift);
252    else if ((inst & intop_mask) == subq_pattern)
253        disp = int((inst & intop_disp_mask) >> intop_disp_shift);
254    else
255        return false;
256
257    return true;
258}
259
260bool
261StackTrace::decodeSave(MachInst inst, int &reg, int &disp)
262{
263    // lda $stq, disp($sp)
264    //
265    // Opcode<31:26> == 0x08
266    // RA<25:21> == ?
267    // RB<20:16> == 30
268    // Disp<15:0>
269    const MachInst stq_mask = 0xfc1f0000;
270    const MachInst stq_pattern = 0xb41e0000;
271    const MachInst stq_disp_mask = 0x0000ffff;
272    const MachInst reg_mask = 0x03e00000;
273    const int reg_shift = 21;
274
275    if ((inst & stq_mask) == stq_pattern) {
276        reg = (inst & reg_mask) >> reg_shift;
277        disp = sext<16>(inst & stq_disp_mask);
278    } else {
279        return false;
280    }
281
282    return true;
283}
284
285/*
286 * Decode the function prologue for the function we're in, and note
287 * which registers are stored where, and how large the stack frame is.
288 */
289bool
290StackTrace::decodePrologue(Addr sp, Addr callpc, Addr func,
291                           int &size, Addr &ra)
292{
293    size = 0;
294    ra = 0;
295
296    for (Addr pc = func; pc < callpc; pc += sizeof(MachInst)) {
297        MachInst inst;
298        CopyOut(xc, (uint8_t *)&inst, pc, sizeof(MachInst));
299
300        int reg, disp;
301        if (decodeStack(inst, disp)) {
302            if (size) {
303                // panic("decoding frame size again");
304                return true;
305            }
306            size += disp;
307        } else if (decodeSave(inst, reg, disp)) {
308            if (!ra && reg == ReturnAddressReg) {
309                CopyOut(xc, (uint8_t *)&ra, sp + disp, sizeof(Addr));
310                if (!ra) {
311                    // panic("no return address value pc=%#x\n", pc);
312                    return false;
313                }
314            }
315        }
316    }
317
318    return true;
319}
320
321#if TRACING_ON
322void
323StackTrace::dump()
324{
325    StringWrap name(xc->cpu->name());
326    SymbolTable *symtab = xc->system->kernelSymtab;
327
328    DPRINTFN("------ Stack ------\n");
329
330    string symbol;
331    for (int i = 0, size = stack.size(); i < size; ++i) {
332        Addr addr = stack[size - i - 1];
333        if (addr == user)
334            symbol = "user";
335        else if (addr == console)
336            symbol = "console";
337        else if (addr == unknown)
338            symbol = "unknown";
339        else
340            symtab->findSymbol(addr, symbol);
341
342        DPRINTFN("%#x: %s\n", addr, symbol);
343    }
344}
345#endif
346