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5d5314d6 JW |
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 | */ | |
20 | get_char_func kdb_poll_funcs[] = { | |
21 | dbg_io_get_char, | |
22 | NULL, | |
f5316b4a JW |
23 | NULL, |
24 | NULL, | |
25 | NULL, | |
26 | NULL, | |
5d5314d6 | 27 | }; |
f5316b4a JW |
28 | EXPORT_SYMBOL_GPL(kdb_poll_funcs); |
29 | ||
30 | int kdb_poll_idx = 1; | |
31 | EXPORT_SYMBOL_GPL(kdb_poll_idx); | |
5d5314d6 JW |
32 | |
33 | int 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); | |
495363d3 | 89 | kdb_initial_cpu = atomic_read(&kgdb_active); |
5d5314d6 JW |
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); | |
f5316b4a | 96 | KDB_STATE_SET(PAGER); |
5d5314d6 JW |
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 | } | |
5d5314d6 JW |
108 | if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) { |
109 | KDB_STATE_CLEAR(SSBPT); | |
110 | KDB_STATE_CLEAR(DOING_SS); | |
111 | } else { | |
112 | /* Start kdb main loop */ | |
113 | error = kdb_main_loop(KDB_REASON_ENTER, reason, | |
114 | ks->err_code, db_result, ks->linux_regs); | |
115 | } | |
116 | /* | |
117 | * Upon exit from the kdb main loop setup break points and restart | |
118 | * the system based on the requested continue state | |
119 | */ | |
120 | kdb_initial_cpu = -1; | |
121 | kdb_current_task = NULL; | |
122 | kdb_current_regs = NULL; | |
f5316b4a | 123 | KDB_STATE_CLEAR(PAGER); |
5d5314d6 JW |
124 | kdbnearsym_cleanup(); |
125 | if (error == KDB_CMD_KGDB) { | |
126 | if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) { | |
127 | /* | |
128 | * This inteface glue which allows kdb to transition in into | |
129 | * the gdb stub. In order to do this the '?' or '' gdb serial | |
130 | * packet response is processed here. And then control is | |
131 | * passed to the gdbstub. | |
132 | */ | |
133 | if (KDB_STATE(DOING_KGDB)) | |
134 | gdbstub_state(ks, "?"); | |
135 | else | |
136 | gdbstub_state(ks, ""); | |
137 | KDB_STATE_CLEAR(DOING_KGDB); | |
138 | KDB_STATE_CLEAR(DOING_KGDB2); | |
139 | } | |
140 | return DBG_PASS_EVENT; | |
141 | } | |
142 | kdb_bp_install(ks->linux_regs); | |
143 | dbg_activate_sw_breakpoints(); | |
144 | /* Set the exit state to a single step or a continue */ | |
145 | if (KDB_STATE(DOING_SS)) | |
146 | gdbstub_state(ks, "s"); | |
147 | else | |
148 | gdbstub_state(ks, "c"); | |
149 | ||
150 | KDB_FLAG_CLEAR(CATASTROPHIC); | |
151 | ||
152 | /* Invoke arch specific exception handling prior to system resume */ | |
153 | kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e"); | |
154 | if (ks->pass_exception) | |
155 | kgdb_info[ks->cpu].ret_state = 1; | |
156 | if (error == KDB_CMD_CPU) { | |
157 | KDB_STATE_SET(REENTRY); | |
158 | /* | |
159 | * Force clear the single step bit because kdb emulates this | |
160 | * differently vs the gdbstub | |
161 | */ | |
162 | kgdb_single_step = 0; | |
163 | dbg_deactivate_sw_breakpoints(); | |
164 | return DBG_SWITCH_CPU_EVENT; | |
165 | } | |
166 | return kgdb_info[ks->cpu].ret_state; | |
167 | } | |
168 |