xref: /openbmc/linux/lib/Kconfig.kgdb (revision 027c3d34)
1# SPDX-License-Identifier: GPL-2.0-only
2
3config HAVE_ARCH_KGDB
4	bool
5
6# set if architecture has the its kgdb_arch_handle_qxfer_pkt
7# function to enable gdb stub to address XML packet sent from GDB.
8config HAVE_ARCH_KGDB_QXFER_PKT
9	bool
10
11menuconfig KGDB
12	bool "KGDB: kernel debugger"
13	depends on HAVE_ARCH_KGDB
14	depends on DEBUG_KERNEL
15	help
16	  If you say Y here, it will be possible to remotely debug the
17	  kernel using gdb.  It is recommended but not required, that
18	  you also turn on the kernel config option
19	  CONFIG_FRAME_POINTER to aid in producing more reliable stack
20	  backtraces in the external debugger.  Documentation of
21	  kernel debugger is available at http://kgdb.sourceforge.net
22	  as well as in Documentation/dev-tools/kgdb.rst.  If
23	  unsure, say N.
24
25if KGDB
26
27config KGDB_HONOUR_BLOCKLIST
28	bool "KGDB: use kprobe blocklist to prohibit unsafe breakpoints"
29	depends on HAVE_KPROBES
30	depends on MODULES
31	select KPROBES
32	default y
33	help
34	  If set to Y the debug core will use the kprobe blocklist to
35	  identify symbols where it is unsafe to set breakpoints.
36	  In particular this disallows instrumentation of functions
37	  called during debug trap handling and thus makes it very
38	  difficult to inadvertently provoke recursive trap handling.
39
40	  If unsure, say Y.
41
42config KGDB_SERIAL_CONSOLE
43	tristate "KGDB: use kgdb over the serial console"
44	select CONSOLE_POLL
45	select MAGIC_SYSRQ
46	depends on TTY && HW_CONSOLE
47	default y
48	help
49	  Share a serial console with kgdb. Sysrq-g must be used
50	  to break in initially.
51
52config KGDB_TESTS
53	bool "KGDB: internal test suite"
54	default n
55	help
56	  This is a kgdb I/O module specifically designed to test
57	  kgdb's internal functions.  This kgdb I/O module is
58	  intended to for the development of new kgdb stubs
59	  as well as regression testing the kgdb internals.
60	  See the drivers/misc/kgdbts.c for the details about
61	  the tests.  The most basic of this I/O module is to boot
62	  a kernel boot arguments "kgdbwait kgdbts=V1F100"
63
64config KGDB_TESTS_ON_BOOT
65	bool "KGDB: Run tests on boot"
66	depends on KGDB_TESTS
67	default n
68	help
69	  Run the kgdb tests on boot up automatically without the need
70	  to pass in a kernel parameter
71
72config KGDB_TESTS_BOOT_STRING
73	string "KGDB: which internal kgdb tests to run"
74	depends on KGDB_TESTS_ON_BOOT
75	default "V1F100"
76	help
77	  This is the command string to send the kgdb test suite on
78	  boot.  See the drivers/misc/kgdbts.c for detailed
79	  information about other strings you could use beyond the
80	  default of V1F100.
81
82config KGDB_LOW_LEVEL_TRAP
83       bool "KGDB: Allow debugging with traps in notifiers"
84       depends on X86 || MIPS
85       default n
86       help
87	 This will add an extra call back to kgdb for the breakpoint
88	 exception handler which will allow kgdb to step through a
89	 notify handler.
90
91config KGDB_KDB
92	bool "KGDB_KDB: include kdb frontend for kgdb"
93	default n
94	help
95	  KDB frontend for kernel
96
97config KDB_DEFAULT_ENABLE
98	hex "KDB: Select kdb command functions to be enabled by default"
99	depends on KGDB_KDB
100	default 0x1
101	help
102	  Specifiers which kdb commands are enabled by default. This may
103	  be set to 1 or 0 to enable all commands or disable almost all
104	  commands.
105
106	  Alternatively the following bitmask applies:
107
108	    0x0002 - allow arbitrary reads from memory and symbol lookup
109	    0x0004 - allow arbitrary writes to memory
110	    0x0008 - allow current register state to be inspected
111	    0x0010 - allow current register state to be modified
112	    0x0020 - allow passive inspection (backtrace, process list, lsmod)
113	    0x0040 - allow flow control management (breakpoint, single step)
114	    0x0080 - enable signalling of processes
115	    0x0100 - allow machine to be rebooted
116
117	  The config option merely sets the default at boot time. Both
118	  issuing 'echo X > /sys/module/kdb/parameters/cmd_enable' or
119	  setting with kdb.cmd_enable=X kernel command line option will
120	  override the default settings.
121
122config KDB_KEYBOARD
123	bool "KGDB_KDB: keyboard as input device"
124	depends on VT && KGDB_KDB && !PARISC
125	default n
126	help
127	  KDB can use a PS/2 type keyboard for an input device
128
129config KDB_CONTINUE_CATASTROPHIC
130	int "KDB: continue after catastrophic errors"
131	depends on KGDB_KDB
132	default "0"
133	help
134	  This integer controls the behaviour of kdb when the kernel gets a
135	  catastrophic error, i.e. for a panic or oops.
136	  When KDB is active and a catastrophic error occurs, nothing extra
137	  will happen until you type 'go'.
138	  CONFIG_KDB_CONTINUE_CATASTROPHIC == 0 (default). The first time
139	  you type 'go', you will be warned by kdb. The secend time you type
140	  'go', KDB tries to continue. No guarantees that the
141	  kernel is still usable in this situation.
142	  CONFIG_KDB_CONTINUE_CATASTROPHIC == 1. KDB tries to continue.
143	  No guarantees that the kernel is still usable in this situation.
144	  CONFIG_KDB_CONTINUE_CATASTROPHIC == 2. KDB forces a reboot.
145	  If you are not sure, say 0.
146
147config ARCH_HAS_EARLY_DEBUG
148	bool
149	default n
150	help
151	  If an architecture can definitely handle entering the debugger
152	  when early_param's are parsed then it select this config.
153	  Otherwise, if "kgdbwait" is passed on the kernel command line it
154	  won't actually be processed until dbg_late_init() just after the
155	  call to kgdb_arch_late() is made.
156
157	  NOTE: Even if this isn't selected by an architecture we will
158	  still try to register kgdb to handle breakpoints and crashes
159	  when early_param's are parsed, we just won't act on the
160	  "kgdbwait" parameter until dbg_late_init().  If you get a
161	  crash and try to drop into kgdb somewhere between these two
162	  places you might or might not end up being able to use kgdb
163	  depending on exactly how far along the architecture has initted.
164
165endif # KGDB
166