kdb: cleanup unused variables missed in the original kdb merge
[linux-2.6.git] / kernel / debug / kdb / kdb_bt.c
1 /*
2  * Kernel Debugger Architecture Independent Stack Traceback
3  *
4  * This file is subject to the terms and conditions of the GNU General Public
5  * License.  See the file "COPYING" in the main directory of this archive
6  * for more details.
7  *
8  * Copyright (c) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
9  * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
10  */
11
12 #include <linux/ctype.h>
13 #include <linux/string.h>
14 #include <linux/kernel.h>
15 #include <linux/sched.h>
16 #include <linux/kdb.h>
17 #include <linux/nmi.h>
18 #include <asm/system.h>
19 #include "kdb_private.h"
20
21
22 static void kdb_show_stack(struct task_struct *p, void *addr)
23 {
24         int old_lvl = console_loglevel;
25         console_loglevel = 15;
26         kdb_trap_printk++;
27         kdb_set_current_task(p);
28         if (addr) {
29                 show_stack((struct task_struct *)p, addr);
30         } else if (kdb_current_regs) {
31 #ifdef CONFIG_X86
32                 show_stack(p, &kdb_current_regs->sp);
33 #else
34                 show_stack(p, NULL);
35 #endif
36         } else {
37                 show_stack(p, NULL);
38         }
39         console_loglevel = old_lvl;
40         kdb_trap_printk--;
41 }
42
43 /*
44  * kdb_bt
45  *
46  *      This function implements the 'bt' command.  Print a stack
47  *      traceback.
48  *
49  *      bt [<address-expression>]       (addr-exp is for alternate stacks)
50  *      btp <pid>                       Kernel stack for <pid>
51  *      btt <address-expression>        Kernel stack for task structure at
52  *                                      <address-expression>
53  *      bta [DRSTCZEUIMA]               All useful processes, optionally
54  *                                      filtered by state
55  *      btc [<cpu>]                     The current process on one cpu,
56  *                                      default is all cpus
57  *
58  *      bt <address-expression> refers to a address on the stack, that location
59  *      is assumed to contain a return address.
60  *
61  *      btt <address-expression> refers to the address of a struct task.
62  *
63  * Inputs:
64  *      argc    argument count
65  *      argv    argument vector
66  * Outputs:
67  *      None.
68  * Returns:
69  *      zero for success, a kdb diagnostic if error
70  * Locking:
71  *      none.
72  * Remarks:
73  *      Backtrack works best when the code uses frame pointers.  But even
74  *      without frame pointers we should get a reasonable trace.
75  *
76  *      mds comes in handy when examining the stack to do a manual traceback or
77  *      to get a starting point for bt <address-expression>.
78  */
79
80 static int
81 kdb_bt1(struct task_struct *p, unsigned long mask,
82         int argcount, int btaprompt)
83 {
84         char buffer[2];
85         if (kdb_getarea(buffer[0], (unsigned long)p) ||
86             kdb_getarea(buffer[0], (unsigned long)(p+1)-1))
87                 return KDB_BADADDR;
88         if (!kdb_task_state(p, mask))
89                 return 0;
90         kdb_printf("Stack traceback for pid %d\n", p->pid);
91         kdb_ps1(p);
92         kdb_show_stack(p, NULL);
93         if (btaprompt) {
94                 kdb_getstr(buffer, sizeof(buffer),
95                            "Enter <q> to end, <cr> to continue:");
96                 if (buffer[0] == 'q') {
97                         kdb_printf("\n");
98                         return 1;
99                 }
100         }
101         touch_nmi_watchdog();
102         return 0;
103 }
104
105 int
106 kdb_bt(int argc, const char **argv)
107 {
108         int diag;
109         int argcount = 5;
110         int btaprompt = 1;
111         int nextarg;
112         unsigned long addr;
113         long offset;
114
115         /* Prompt after each proc in bta */
116         kdbgetintenv("BTAPROMPT", &btaprompt);
117
118         if (strcmp(argv[0], "bta") == 0) {
119                 struct task_struct *g, *p;
120                 unsigned long cpu;
121                 unsigned long mask = kdb_task_state_string(argc ? argv[1] :
122                                                            NULL);
123                 if (argc == 0)
124                         kdb_ps_suppressed();
125                 /* Run the active tasks first */
126                 for_each_online_cpu(cpu) {
127                         p = kdb_curr_task(cpu);
128                         if (kdb_bt1(p, mask, argcount, btaprompt))
129                                 return 0;
130                 }
131                 /* Now the inactive tasks */
132                 kdb_do_each_thread(g, p) {
133                         if (task_curr(p))
134                                 continue;
135                         if (kdb_bt1(p, mask, argcount, btaprompt))
136                                 return 0;
137                 } kdb_while_each_thread(g, p);
138         } else if (strcmp(argv[0], "btp") == 0) {
139                 struct task_struct *p;
140                 unsigned long pid;
141                 if (argc != 1)
142                         return KDB_ARGCOUNT;
143                 diag = kdbgetularg((char *)argv[1], &pid);
144                 if (diag)
145                         return diag;
146                 p = find_task_by_pid_ns(pid, &init_pid_ns);
147                 if (p) {
148                         kdb_set_current_task(p);
149                         return kdb_bt1(p, ~0UL, argcount, 0);
150                 }
151                 kdb_printf("No process with pid == %ld found\n", pid);
152                 return 0;
153         } else if (strcmp(argv[0], "btt") == 0) {
154                 if (argc != 1)
155                         return KDB_ARGCOUNT;
156                 diag = kdbgetularg((char *)argv[1], &addr);
157                 if (diag)
158                         return diag;
159                 kdb_set_current_task((struct task_struct *)addr);
160                 return kdb_bt1((struct task_struct *)addr, ~0UL, argcount, 0);
161         } else if (strcmp(argv[0], "btc") == 0) {
162                 unsigned long cpu = ~0;
163                 struct task_struct *save_current_task = kdb_current_task;
164                 char buf[80];
165                 if (argc > 1)
166                         return KDB_ARGCOUNT;
167                 if (argc == 1) {
168                         diag = kdbgetularg((char *)argv[1], &cpu);
169                         if (diag)
170                                 return diag;
171                 }
172                 /* Recursive use of kdb_parse, do not use argv after
173                  * this point */
174                 argv = NULL;
175                 if (cpu != ~0) {
176                         if (cpu >= num_possible_cpus() || !cpu_online(cpu)) {
177                                 kdb_printf("no process for cpu %ld\n", cpu);
178                                 return 0;
179                         }
180                         sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu));
181                         kdb_parse(buf);
182                         return 0;
183                 }
184                 kdb_printf("btc: cpu status: ");
185                 kdb_parse("cpu\n");
186                 for_each_online_cpu(cpu) {
187                         sprintf(buf, "btt 0x%p\n", KDB_TSK(cpu));
188                         kdb_parse(buf);
189                         touch_nmi_watchdog();
190                 }
191                 kdb_set_current_task(save_current_task);
192                 return 0;
193         } else {
194                 if (argc) {
195                         nextarg = 1;
196                         diag = kdbgetaddrarg(argc, argv, &nextarg, &addr,
197                                              &offset, NULL);
198                         if (diag)
199                                 return diag;
200                         kdb_show_stack(kdb_current_task, (void *)addr);
201                         return 0;
202                 } else {
203                         return kdb_bt1(kdb_current_task, ~0UL, argcount, 0);
204                 }
205         }
206
207         /* NOTREACHED */
208         return 0;
209 }