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# SPDX-License-Identifier: GPL-2.0-only
config HAVE_ARCH_KGDB
bool
# set if architecture has the its kgdb_arch_handle_qxfer_pkt
# function to enable gdb stub to address XML packet sent from GDB.
config HAVE_ARCH_KGDB_QXFER_PKT
bool
menuconfig KGDB
bool "KGDB: kernel debugger"
depends on HAVE_ARCH_KGDB
depends on DEBUG_KERNEL
help
If you say Y here, it will be possible to remotely debug the
kernel using gdb. It is recommended but not required, that
you also turn on the kernel config option
CONFIG_FRAME_POINTER to aid in producing more reliable stack
backtraces in the external debugger. Documentation of
kernel debugger is available at http://kgdb.sourceforge.net
as well as in Documentation/dev-tools/kgdb.rst. If
unsure, say N.
if KGDB
config KGDB_HONOUR_BLOCKLIST
bool "KGDB: use kprobe blocklist to prohibit unsafe breakpoints"
depends on HAVE_KPROBES
depends on MODULES
select KPROBES
default y
help
If set to Y the debug core will use the kprobe blocklist to
identify symbols where it is unsafe to set breakpoints.
In particular this disallows instrumentation of functions
called during debug trap handling and thus makes it very
difficult to inadvertently provoke recursive trap handling.
If unsure, say Y.
config KGDB_SERIAL_CONSOLE
tristate "KGDB: use kgdb over the serial console"
select CONSOLE_POLL
select MAGIC_SYSRQ
depends on TTY && HW_CONSOLE
default y
help
Share a serial console with kgdb. Sysrq-g must be used
to break in initially.
config KGDB_TESTS
bool "KGDB: internal test suite"
default n
help
This is a kgdb I/O module specifically designed to test
kgdb's internal functions. This kgdb I/O module is
intended to for the development of new kgdb stubs
as well as regression testing the kgdb internals.
See the drivers/misc/kgdbts.c for the details about
the tests. The most basic of this I/O module is to boot
a kernel boot arguments "kgdbwait kgdbts=V1F100"
config KGDB_TESTS_ON_BOOT
bool "KGDB: Run tests on boot"
depends on KGDB_TESTS
default n
help
Run the kgdb tests on boot up automatically without the need
to pass in a kernel parameter
config KGDB_TESTS_BOOT_STRING
string "KGDB: which internal kgdb tests to run"
depends on KGDB_TESTS_ON_BOOT
default "V1F100"
help
This is the command string to send the kgdb test suite on
boot. See the drivers/misc/kgdbts.c for detailed
information about other strings you could use beyond the
default of V1F100.
config KGDB_LOW_LEVEL_TRAP
bool "KGDB: Allow debugging with traps in notifiers"
depends on X86 || MIPS
default n
help
This will add an extra call back to kgdb for the breakpoint
exception handler which will allow kgdb to step through a
notify handler.
config KGDB_KDB
bool "KGDB_KDB: include kdb frontend for kgdb"
default n
help
KDB frontend for kernel
config KDB_DEFAULT_ENABLE
hex "KDB: Select kdb command functions to be enabled by default"
depends on KGDB_KDB
default 0x1
help
Specifiers which kdb commands are enabled by default. This may
be set to 1 or 0 to enable all commands or disable almost all
commands.
Alternatively the following bitmask applies:
0x0002 - allow arbitrary reads from memory and symbol lookup
0x0004 - allow arbitrary writes to memory
0x0008 - allow current register state to be inspected
0x0010 - allow current register state to be modified
0x0020 - allow passive inspection (backtrace, process list, lsmod)
0x0040 - allow flow control management (breakpoint, single step)
0x0080 - enable signalling of processes
0x0100 - allow machine to be rebooted
The config option merely sets the default at boot time. Both
issuing 'echo X > /sys/module/kdb/parameters/cmd_enable' or
setting with kdb.cmd_enable=X kernel command line option will
override the default settings.
config KDB_KEYBOARD
bool "KGDB_KDB: keyboard as input device"
depends on VT && KGDB_KDB && !PARISC
default n
help
KDB can use a PS/2 type keyboard for an input device
config KDB_CONTINUE_CATASTROPHIC
int "KDB: continue after catastrophic errors"
depends on KGDB_KDB
default "0"
help
This integer controls the behaviour of kdb when the kernel gets a
catastrophic error, i.e. for a panic or oops.
When KDB is active and a catastrophic error occurs, nothing extra
will happen until you type 'go'.
CONFIG_KDB_CONTINUE_CATASTROPHIC == 0 (default). The first time
you type 'go', you will be warned by kdb. The secend time you type
'go', KDB tries to continue. No guarantees that the
kernel is still usable in this situation.
CONFIG_KDB_CONTINUE_CATASTROPHIC == 1. KDB tries to continue.
No guarantees that the kernel is still usable in this situation.
CONFIG_KDB_CONTINUE_CATASTROPHIC == 2. KDB forces a reboot.
If you are not sure, say 0.
config ARCH_HAS_EARLY_DEBUG
bool
default n
help
If an architecture can definitely handle entering the debugger
when early_param's are parsed then it select this config.
Otherwise, if "kgdbwait" is passed on the kernel command line it
won't actually be processed until dbg_late_init() just after the
call to kgdb_arch_late() is made.
NOTE: Even if this isn't selected by an architecture we will
still try to register kgdb to handle breakpoints and crashes
when early_param's are parsed, we just won't act on the
"kgdbwait" parameter until dbg_late_init(). If you get a
crash and try to drop into kgdb somewhere between these two
places you might or might not end up being able to use kgdb
depending on exactly how far along the architecture has initted.
endif # KGDB
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