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