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-rw-r--r--kernel/debug/kdb/kdb_debugger.c169
1 files changed, 169 insertions, 0 deletions
diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c
new file mode 100644
index 000000000000..bf6e8270e957
--- /dev/null
+++ b/kernel/debug/kdb/kdb_debugger.c
@@ -0,0 +1,169 @@
1/*
2 * Created by: Jason Wessel <jason.wessel@windriver.com>
3 *
4 * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
5 *
6 * This file is licensed under the terms of the GNU General Public
7 * License version 2. This program is licensed "as is" without any
8 * warranty of any kind, whether express or implied.
9 */
10
11#include <linux/kgdb.h>
12#include <linux/kdb.h>
13#include <linux/kdebug.h>
14#include "kdb_private.h"
15#include "../debug_core.h"
16
17/*
18 * KDB interface to KGDB internals
19 */
20get_char_func kdb_poll_funcs[] = {
21 dbg_io_get_char,
22 NULL,
23 NULL,
24 NULL,
25 NULL,
26 NULL,
27};
28EXPORT_SYMBOL_GPL(kdb_poll_funcs);
29
30int kdb_poll_idx = 1;
31EXPORT_SYMBOL_GPL(kdb_poll_idx);
32
33int kdb_stub(struct kgdb_state *ks)
34{
35 int error = 0;
36 kdb_bp_t *bp;
37 unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
38 kdb_reason_t reason = KDB_REASON_OOPS;
39 kdb_dbtrap_t db_result = KDB_DB_NOBPT;
40 int i;
41
42 if (KDB_STATE(REENTRY)) {
43 reason = KDB_REASON_SWITCH;
44 KDB_STATE_CLEAR(REENTRY);
45 addr = instruction_pointer(ks->linux_regs);
46 }
47 ks->pass_exception = 0;
48 if (atomic_read(&kgdb_setting_breakpoint))
49 reason = KDB_REASON_KEYBOARD;
50
51 for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
52 if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
53 reason = KDB_REASON_BREAK;
54 db_result = KDB_DB_BPT;
55 if (addr != instruction_pointer(ks->linux_regs))
56 kgdb_arch_set_pc(ks->linux_regs, addr);
57 break;
58 }
59 }
60 if (reason == KDB_REASON_BREAK || reason == KDB_REASON_SWITCH) {
61 for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
62 if (bp->bp_free)
63 continue;
64 if (bp->bp_addr == addr) {
65 bp->bp_delay = 1;
66 bp->bp_delayed = 1;
67 /*
68 * SSBPT is set when the kernel debugger must single step a
69 * task in order to re-establish an instruction breakpoint
70 * which uses the instruction replacement mechanism. It is
71 * cleared by any action that removes the need to single-step
72 * the breakpoint.
73 */
74 reason = KDB_REASON_BREAK;
75 db_result = KDB_DB_BPT;
76 KDB_STATE_SET(SSBPT);
77 break;
78 }
79 }
80 }
81
82 if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
83 ks->signo == SIGTRAP) {
84 reason = KDB_REASON_SSTEP;
85 db_result = KDB_DB_BPT;
86 }
87 /* Set initial kdb state variables */
88 KDB_STATE_CLEAR(KGDB_TRANS);
89 kdb_initial_cpu = ks->cpu;
90 kdb_current_task = kgdb_info[ks->cpu].task;
91 kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
92 /* Remove any breakpoints as needed by kdb and clear single step */
93 kdb_bp_remove();
94 KDB_STATE_CLEAR(DOING_SS);
95 KDB_STATE_CLEAR(DOING_SSB);
96 KDB_STATE_SET(PAGER);
97 /* zero out any offline cpu data */
98 for_each_present_cpu(i) {
99 if (!cpu_online(i)) {
100 kgdb_info[i].debuggerinfo = NULL;
101 kgdb_info[i].task = NULL;
102 }
103 }
104 if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) {
105 ks->pass_exception = 1;
106 KDB_FLAG_SET(CATASTROPHIC);
107 }
108 kdb_initial_cpu = ks->cpu;
109 if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
110 KDB_STATE_CLEAR(SSBPT);
111 KDB_STATE_CLEAR(DOING_SS);
112 } else {
113 /* Start kdb main loop */
114 error = kdb_main_loop(KDB_REASON_ENTER, reason,
115 ks->err_code, db_result, ks->linux_regs);
116 }
117 /*
118 * Upon exit from the kdb main loop setup break points and restart
119 * the system based on the requested continue state
120 */
121 kdb_initial_cpu = -1;
122 kdb_current_task = NULL;
123 kdb_current_regs = NULL;
124 KDB_STATE_CLEAR(PAGER);
125 kdbnearsym_cleanup();
126 if (error == KDB_CMD_KGDB) {
127 if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {
128 /*
129 * This inteface glue which allows kdb to transition in into
130 * the gdb stub. In order to do this the '?' or '' gdb serial
131 * packet response is processed here. And then control is
132 * passed to the gdbstub.
133 */
134 if (KDB_STATE(DOING_KGDB))
135 gdbstub_state(ks, "?");
136 else
137 gdbstub_state(ks, "");
138 KDB_STATE_CLEAR(DOING_KGDB);
139 KDB_STATE_CLEAR(DOING_KGDB2);
140 }
141 return DBG_PASS_EVENT;
142 }
143 kdb_bp_install(ks->linux_regs);
144 dbg_activate_sw_breakpoints();
145 /* Set the exit state to a single step or a continue */
146 if (KDB_STATE(DOING_SS))
147 gdbstub_state(ks, "s");
148 else
149 gdbstub_state(ks, "c");
150
151 KDB_FLAG_CLEAR(CATASTROPHIC);
152
153 /* Invoke arch specific exception handling prior to system resume */
154 kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
155 if (ks->pass_exception)
156 kgdb_info[ks->cpu].ret_state = 1;
157 if (error == KDB_CMD_CPU) {
158 KDB_STATE_SET(REENTRY);
159 /*
160 * Force clear the single step bit because kdb emulates this
161 * differently vs the gdbstub
162 */
163 kgdb_single_step = 0;
164 dbg_deactivate_sw_breakpoints();
165 return DBG_SWITCH_CPU_EVENT;
166 }
167 return kgdb_info[ks->cpu].ret_state;
168}
169
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