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 <linux/export.h> |
15 | #include <linux/hardirq.h> |
16 | #include "kdb_private.h" |
17 | #include "../debug_core.h" |
18 | |
19 | /* |
20 | * KDB interface to KGDB internals |
21 | */ |
22 | get_char_func kdb_poll_funcs[] = { |
23 | dbg_io_get_char, |
24 | NULL, |
25 | NULL, |
26 | NULL, |
27 | NULL, |
28 | NULL, |
29 | }; |
30 | EXPORT_SYMBOL_GPL(kdb_poll_funcs); |
31 | |
32 | int kdb_poll_idx = 1; |
33 | EXPORT_SYMBOL_GPL(kdb_poll_idx); |
34 | |
35 | static struct kgdb_state *kdb_ks; |
36 | |
37 | int kdb_common_init_state(struct kgdb_state *ks) |
38 | { |
39 | kdb_initial_cpu = atomic_read(v: &kgdb_active); |
40 | kdb_current_task = kgdb_info[ks->cpu].task; |
41 | kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo; |
42 | return 0; |
43 | } |
44 | |
45 | int kdb_common_deinit_state(void) |
46 | { |
47 | kdb_initial_cpu = -1; |
48 | kdb_current_task = NULL; |
49 | kdb_current_regs = NULL; |
50 | return 0; |
51 | } |
52 | |
53 | int kdb_stub(struct kgdb_state *ks) |
54 | { |
55 | int error = 0; |
56 | kdb_bp_t *bp; |
57 | unsigned long addr = kgdb_arch_pc(exception: ks->ex_vector, regs: ks->linux_regs); |
58 | kdb_reason_t reason = KDB_REASON_OOPS; |
59 | kdb_dbtrap_t db_result = KDB_DB_NOBPT; |
60 | int i; |
61 | |
62 | kdb_ks = ks; |
63 | if (KDB_STATE(REENTRY)) { |
64 | reason = KDB_REASON_SWITCH; |
65 | KDB_STATE_CLEAR(REENTRY); |
66 | addr = instruction_pointer(regs: ks->linux_regs); |
67 | } |
68 | ks->pass_exception = 0; |
69 | if (atomic_read(v: &kgdb_setting_breakpoint)) |
70 | reason = KDB_REASON_KEYBOARD; |
71 | |
72 | if (ks->err_code == KDB_REASON_SYSTEM_NMI && ks->signo == SIGTRAP) |
73 | reason = KDB_REASON_SYSTEM_NMI; |
74 | |
75 | else if (in_nmi()) |
76 | reason = KDB_REASON_NMI; |
77 | |
78 | for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) { |
79 | if ((bp->bp_enabled) && (bp->bp_addr == addr)) { |
80 | reason = KDB_REASON_BREAK; |
81 | db_result = KDB_DB_BPT; |
82 | if (addr != instruction_pointer(regs: ks->linux_regs)) |
83 | kgdb_arch_set_pc(regs: ks->linux_regs, pc: addr); |
84 | break; |
85 | } |
86 | } |
87 | if (reason == KDB_REASON_BREAK || reason == KDB_REASON_SWITCH) { |
88 | for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) { |
89 | if (bp->bp_free) |
90 | continue; |
91 | if (bp->bp_addr == addr) { |
92 | bp->bp_delay = 1; |
93 | bp->bp_delayed = 1; |
94 | /* |
95 | * SSBPT is set when the kernel debugger must single step a |
96 | * task in order to re-establish an instruction breakpoint |
97 | * which uses the instruction replacement mechanism. It is |
98 | * cleared by any action that removes the need to single-step |
99 | * the breakpoint. |
100 | */ |
101 | reason = KDB_REASON_BREAK; |
102 | db_result = KDB_DB_BPT; |
103 | KDB_STATE_SET(SSBPT); |
104 | break; |
105 | } |
106 | } |
107 | } |
108 | |
109 | if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 && |
110 | ks->signo == SIGTRAP) { |
111 | reason = KDB_REASON_SSTEP; |
112 | db_result = KDB_DB_BPT; |
113 | } |
114 | /* Set initial kdb state variables */ |
115 | KDB_STATE_CLEAR(KGDB_TRANS); |
116 | kdb_common_init_state(ks); |
117 | /* Remove any breakpoints as needed by kdb and clear single step */ |
118 | kdb_bp_remove(); |
119 | KDB_STATE_CLEAR(DOING_SS); |
120 | KDB_STATE_SET(PAGER); |
121 | if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) { |
122 | ks->pass_exception = 1; |
123 | KDB_FLAG_SET(CATASTROPHIC); |
124 | } |
125 | /* set CATASTROPHIC if the system contains unresponsive processors */ |
126 | for_each_online_cpu(i) |
127 | if (!kgdb_info[i].enter_kgdb) |
128 | KDB_FLAG_SET(CATASTROPHIC); |
129 | if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) { |
130 | KDB_STATE_CLEAR(SSBPT); |
131 | KDB_STATE_CLEAR(DOING_SS); |
132 | } else { |
133 | /* Start kdb main loop */ |
134 | error = kdb_main_loop(KDB_REASON_ENTER, reason, |
135 | ks->err_code, db_result, ks->linux_regs); |
136 | } |
137 | /* |
138 | * Upon exit from the kdb main loop setup break points and restart |
139 | * the system based on the requested continue state |
140 | */ |
141 | kdb_common_deinit_state(); |
142 | KDB_STATE_CLEAR(PAGER); |
143 | if (error == KDB_CMD_KGDB) { |
144 | if (KDB_STATE(DOING_KGDB)) |
145 | KDB_STATE_CLEAR(DOING_KGDB); |
146 | return DBG_PASS_EVENT; |
147 | } |
148 | kdb_bp_install(ks->linux_regs); |
149 | /* Set the exit state to a single step or a continue */ |
150 | if (KDB_STATE(DOING_SS)) |
151 | gdbstub_state(ks, cmd: "s" ); |
152 | else |
153 | gdbstub_state(ks, cmd: "c" ); |
154 | |
155 | KDB_FLAG_CLEAR(CATASTROPHIC); |
156 | |
157 | /* Invoke arch specific exception handling prior to system resume */ |
158 | kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, cmd: "e" ); |
159 | if (ks->pass_exception) |
160 | kgdb_info[ks->cpu].ret_state = 1; |
161 | if (error == KDB_CMD_CPU) { |
162 | KDB_STATE_SET(REENTRY); |
163 | /* |
164 | * Force clear the single step bit because kdb emulates this |
165 | * differently vs the gdbstub |
166 | */ |
167 | kgdb_single_step = 0; |
168 | return DBG_SWITCH_CPU_EVENT; |
169 | } |
170 | return kgdb_info[ks->cpu].ret_state; |
171 | } |
172 | |
173 | void kdb_gdb_state_pass(char *buf) |
174 | { |
175 | gdbstub_state(ks: kdb_ks, cmd: buf); |
176 | } |
177 | |