1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 2
3 config HAVE_ARCH_KGDB 3 config HAVE_ARCH_KGDB
4 bool 4 bool
5 5
6 # set if architecture has the its kgdb_arch_ha 6 # set if architecture has the its kgdb_arch_handle_qxfer_pkt
7 # function to enable gdb stub to address XML p 7 # function to enable gdb stub to address XML packet sent from GDB.
8 config HAVE_ARCH_KGDB_QXFER_PKT 8 config HAVE_ARCH_KGDB_QXFER_PKT
9 bool 9 bool
10 10
11 menuconfig KGDB 11 menuconfig KGDB
12 bool "KGDB: kernel debugger" 12 bool "KGDB: kernel debugger"
13 depends on HAVE_ARCH_KGDB 13 depends on HAVE_ARCH_KGDB
14 depends on DEBUG_KERNEL 14 depends on DEBUG_KERNEL
15 help 15 help
16 If you say Y here, it will be possib 16 If you say Y here, it will be possible to remotely debug the
17 kernel using gdb. It is recommended 17 kernel using gdb. It is recommended but not required, that
18 you also turn on the kernel config o 18 you also turn on the kernel config option
19 CONFIG_FRAME_POINTER to aid in produ 19 CONFIG_FRAME_POINTER to aid in producing more reliable stack
20 backtraces in the external debugger. 20 backtraces in the external debugger. Documentation of
21 kernel debugger is available at http 21 kernel debugger is available at http://kgdb.sourceforge.net
22 as well as in Documentation/dev-tool 22 as well as in Documentation/dev-tools/kgdb.rst. If
23 unsure, say N. 23 unsure, say N.
24 24
25 if KGDB 25 if KGDB
26 26
27 config KGDB_HONOUR_BLOCKLIST 27 config KGDB_HONOUR_BLOCKLIST
28 bool "KGDB: use kprobe blocklist to pr 28 bool "KGDB: use kprobe blocklist to prohibit unsafe breakpoints"
29 depends on HAVE_KPROBES 29 depends on HAVE_KPROBES
30 depends on MODULES 30 depends on MODULES
31 select KPROBES 31 select KPROBES
32 default y 32 default y
33 help 33 help
34 If set to Y the debug core will use 34 If set to Y the debug core will use the kprobe blocklist to
35 identify symbols where it is unsafe 35 identify symbols where it is unsafe to set breakpoints.
36 In particular this disallows instrum 36 In particular this disallows instrumentation of functions
37 called during debug trap handling an 37 called during debug trap handling and thus makes it very
38 difficult to inadvertently provoke r 38 difficult to inadvertently provoke recursive trap handling.
39 39
40 If unsure, say Y. 40 If unsure, say Y.
41 41
42 config KGDB_SERIAL_CONSOLE 42 config KGDB_SERIAL_CONSOLE
43 tristate "KGDB: use kgdb over the seri 43 tristate "KGDB: use kgdb over the serial console"
44 select CONSOLE_POLL 44 select CONSOLE_POLL
45 select MAGIC_SYSRQ 45 select MAGIC_SYSRQ
46 depends on TTY && VT !! 46 depends on TTY && HW_CONSOLE
47 default y 47 default y
48 help 48 help
49 Share a serial console with kgdb. Sy 49 Share a serial console with kgdb. Sysrq-g must be used
50 to break in initially. 50 to break in initially.
51 51
52 config KGDB_TESTS 52 config KGDB_TESTS
53 bool "KGDB: internal test suite" 53 bool "KGDB: internal test suite"
54 default n 54 default n
55 help 55 help
56 This is a kgdb I/O module specifical 56 This is a kgdb I/O module specifically designed to test
57 kgdb's internal functions. This kgd 57 kgdb's internal functions. This kgdb I/O module is
58 intended to for the development of n 58 intended to for the development of new kgdb stubs
59 as well as regression testing the kg 59 as well as regression testing the kgdb internals.
60 See the drivers/misc/kgdbts.c for th 60 See the drivers/misc/kgdbts.c for the details about
61 the tests. The most basic of this I 61 the tests. The most basic of this I/O module is to boot
62 a kernel boot arguments "kgdbwait kg 62 a kernel boot arguments "kgdbwait kgdbts=V1F100"
63 63
64 config KGDB_TESTS_ON_BOOT 64 config KGDB_TESTS_ON_BOOT
65 bool "KGDB: Run tests on boot" 65 bool "KGDB: Run tests on boot"
66 depends on KGDB_TESTS 66 depends on KGDB_TESTS
67 default n 67 default n
68 help 68 help
69 Run the kgdb tests on boot up automa 69 Run the kgdb tests on boot up automatically without the need
70 to pass in a kernel parameter 70 to pass in a kernel parameter
71 71
72 config KGDB_TESTS_BOOT_STRING 72 config KGDB_TESTS_BOOT_STRING
73 string "KGDB: which internal kgdb test 73 string "KGDB: which internal kgdb tests to run"
74 depends on KGDB_TESTS_ON_BOOT 74 depends on KGDB_TESTS_ON_BOOT
75 default "V1F100" 75 default "V1F100"
76 help 76 help
77 This is the command string to send t 77 This is the command string to send the kgdb test suite on
78 boot. See the drivers/misc/kgdbts.c 78 boot. See the drivers/misc/kgdbts.c for detailed
79 information about other strings you 79 information about other strings you could use beyond the
80 default of V1F100. 80 default of V1F100.
81 81
82 config KGDB_LOW_LEVEL_TRAP 82 config KGDB_LOW_LEVEL_TRAP
83 bool "KGDB: Allow debugging with traps 83 bool "KGDB: Allow debugging with traps in notifiers"
84 depends on X86 || MIPS 84 depends on X86 || MIPS
85 default n 85 default n
86 help 86 help
87 This will add an extra call back to k 87 This will add an extra call back to kgdb for the breakpoint
88 exception handler which will allow kg 88 exception handler which will allow kgdb to step through a
89 notify handler. 89 notify handler.
90 90
91 config KGDB_KDB 91 config KGDB_KDB
92 bool "KGDB_KDB: include kdb frontend f 92 bool "KGDB_KDB: include kdb frontend for kgdb"
93 default n 93 default n
94 help 94 help
95 KDB frontend for kernel 95 KDB frontend for kernel
96 96
97 config KDB_DEFAULT_ENABLE 97 config KDB_DEFAULT_ENABLE
98 hex "KDB: Select kdb command functions 98 hex "KDB: Select kdb command functions to be enabled by default"
99 depends on KGDB_KDB 99 depends on KGDB_KDB
100 default 0x1 100 default 0x1
101 help 101 help
102 Specifiers which kdb commands are en 102 Specifiers which kdb commands are enabled by default. This may
103 be set to 1 or 0 to enable all comma 103 be set to 1 or 0 to enable all commands or disable almost all
104 commands. 104 commands.
105 105
106 Alternatively the following bitmask 106 Alternatively the following bitmask applies:
107 107
108 0x0002 - allow arbitrary reads fro 108 0x0002 - allow arbitrary reads from memory and symbol lookup
109 0x0004 - allow arbitrary writes to 109 0x0004 - allow arbitrary writes to memory
110 0x0008 - allow current register st 110 0x0008 - allow current register state to be inspected
111 0x0010 - allow current register st 111 0x0010 - allow current register state to be modified
112 0x0020 - allow passive inspection 112 0x0020 - allow passive inspection (backtrace, process list, lsmod)
113 0x0040 - allow flow control manage 113 0x0040 - allow flow control management (breakpoint, single step)
114 0x0080 - enable signalling of proc 114 0x0080 - enable signalling of processes
115 0x0100 - allow machine to be reboo 115 0x0100 - allow machine to be rebooted
116 116
117 The config option merely sets the de 117 The config option merely sets the default at boot time. Both
118 issuing 'echo X > /sys/module/kdb/pa 118 issuing 'echo X > /sys/module/kdb/parameters/cmd_enable' or
119 setting with kdb.cmd_enable=X kernel 119 setting with kdb.cmd_enable=X kernel command line option will
120 override the default settings. 120 override the default settings.
121 121
122 config KDB_KEYBOARD 122 config KDB_KEYBOARD
123 bool "KGDB_KDB: keyboard as input devi 123 bool "KGDB_KDB: keyboard as input device"
124 depends on VT && KGDB_KDB && !PARISC 124 depends on VT && KGDB_KDB && !PARISC
125 depends on HAS_IOPORT <<
126 default n 125 default n
127 help 126 help
128 KDB can use a PS/2 type keyboard for 127 KDB can use a PS/2 type keyboard for an input device
129 128
130 config KDB_CONTINUE_CATASTROPHIC 129 config KDB_CONTINUE_CATASTROPHIC
131 int "KDB: continue after catastrophic 130 int "KDB: continue after catastrophic errors"
132 depends on KGDB_KDB 131 depends on KGDB_KDB
133 default "0" 132 default "0"
134 help 133 help
135 This integer controls the behaviour 134 This integer controls the behaviour of kdb when the kernel gets a
136 catastrophic error, i.e. for a panic 135 catastrophic error, i.e. for a panic or oops.
137 When KDB is active and a catastrophi 136 When KDB is active and a catastrophic error occurs, nothing extra
138 will happen until you type 'go'. 137 will happen until you type 'go'.
139 CONFIG_KDB_CONTINUE_CATASTROPHIC == 138 CONFIG_KDB_CONTINUE_CATASTROPHIC == 0 (default). The first time
140 you type 'go', you will be warned by 139 you type 'go', you will be warned by kdb. The secend time you type
141 'go', KDB tries to continue. No guar 140 'go', KDB tries to continue. No guarantees that the
142 kernel is still usable in this situa 141 kernel is still usable in this situation.
143 CONFIG_KDB_CONTINUE_CATASTROPHIC == 142 CONFIG_KDB_CONTINUE_CATASTROPHIC == 1. KDB tries to continue.
144 No guarantees that the kernel is sti 143 No guarantees that the kernel is still usable in this situation.
145 CONFIG_KDB_CONTINUE_CATASTROPHIC == 144 CONFIG_KDB_CONTINUE_CATASTROPHIC == 2. KDB forces a reboot.
146 If you are not sure, say 0. 145 If you are not sure, say 0.
147 146
148 config ARCH_HAS_EARLY_DEBUG 147 config ARCH_HAS_EARLY_DEBUG
149 bool 148 bool
150 default n 149 default n
151 help 150 help
152 If an architecture can definitely ha 151 If an architecture can definitely handle entering the debugger
153 when early_param's are parsed then i 152 when early_param's are parsed then it select this config.
154 Otherwise, if "kgdbwait" is passed o 153 Otherwise, if "kgdbwait" is passed on the kernel command line it
155 won't actually be processed until db 154 won't actually be processed until dbg_late_init() just after the
156 call to kgdb_arch_late() is made. 155 call to kgdb_arch_late() is made.
157 156
158 NOTE: Even if this isn't selected by 157 NOTE: Even if this isn't selected by an architecture we will
159 still try to register kgdb to handle 158 still try to register kgdb to handle breakpoints and crashes
160 when early_param's are parsed, we ju 159 when early_param's are parsed, we just won't act on the
161 "kgdbwait" parameter until dbg_late_ 160 "kgdbwait" parameter until dbg_late_init(). If you get a
162 crash and try to drop into kgdb some 161 crash and try to drop into kgdb somewhere between these two
163 places you might or might not end up 162 places you might or might not end up being able to use kgdb
164 depending on exactly how far along t 163 depending on exactly how far along the architecture has initted.
165 164
166 endif # KGDB 165 endif # KGDB
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