linux/lib/Kconfig.kgdb
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   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
 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