path: root/lib/Kconfig.debug

config PRINTK_TIME
	bool "Show timing information on printks"
	depends on PRINTK
	help
	  Selecting this option causes timing information to be
	  included in printk output.  This allows you to measure
	  the interval between kernel operations, including bootup
	  operations.  This is useful for identifying long delays
	  in kernel startup.

config ENABLE_WARN_DEPRECATED
	bool "Enable __deprecated logic"
	default y
	help
	  Enable the __deprecated logic in the kernel build.
	  Disable this to suppress the "warning: 'foo' is deprecated
	  (declared at kernel/power/somefile.c:1234)" messages.

config ENABLE_MUST_CHECK
	bool "Enable __must_check logic"
	default y
	help
	  Enable the __must_check logic in the kernel build.  Disable this to
	  suppress the "warning: ignoring return value of 'foo', declared with
	  attribute warn_unused_result" messages.

config FRAME_WARN
	int "Warn for stack frames larger than (needs gcc 4.4)"
	range 0 8192
	default 1024 if !64BIT
	default 2048 if 64BIT
	help
	  Tell gcc to warn at build time for stack frames larger than this.
	  Setting this too low will cause a lot of warnings.
	  Setting it to 0 disables the warning.
	  Requires gcc 4.4

config MAGIC_SYSRQ
	bool "Magic SysRq key"
	depends on !UML
	help
	  If you say Y here, you will have some control over the system even
	  if the system crashes for example during kernel debugging (e.g., you
	  will be able to flush the buffer cache to disk, reboot the system
	  immediately or dump some status information). This is accomplished
	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
	  also works on a serial console (on PC hardware at least), if you
	  send a BREAK and then within 5 seconds a command keypress. The
	  keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
	  unless you really know what this hack does.

config STRIP_ASM_SYMS
	bool "Strip assembler-generated symbols during link"
	default n
	help
	  Strip internal assembler-generated symbols during a link (symbols
	  that look like '.Lxxx') so they don't pollute the output of
	  get_wchan() and suchlike.

config UNUSED_SYMBOLS
	bool "Enable unused/obsolete exported symbols"
	default y if X86
	help
	  Unused but exported symbols make the kernel needlessly bigger.  For
	  that reason most of these unused exports will soon be removed.  This
	  option is provided temporarily to provide a transition period in case
	  some external kernel module needs one of these symbols anyway. If you
	  encounter such a case in your module, consider if you are actually
	  using the right API.  (rationale: since nobody in the kernel is using
	  this in a module, there is a pretty good chance it's actually the
	  wrong interface to use).  If you really need the symbol, please send a
	  mail to the linux kernel mailing list mentioning the symbol and why
	  you really need it, and what the merge plan to the mainline kernel for
	  your module is.

config DEBUG_FS
	bool "Debug Filesystem"
	help
	  debugfs is a virtual file system that kernel developers use to put
	  debugging files into.  Enable this option to be able to read and
	  write to these files.

	  For detailed documentation on the debugfs API, see
	  Documentation/DocBook/filesystems.

	  If unsure, say N.

config HEADERS_CHECK
	bool "Run 'make headers_check' when building vmlinux"
	depends on !UML
	help
	  This option will extract the user-visible kernel headers whenever
	  building the kernel, and will run basic sanity checks on them to
	  ensure that exported files do not attempt to include files which
	  were not exported, etc.

	  If you're making modifications to header files which are
	  relevant for userspace, say 'Y', and check the headers
	  exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
	  your build tree), to make sure they're suitable.

config DEBUG_SECTION_MISMATCH
	bool "Enable full Section mismatch analysis"
	depends on UNDEFINED || (BLACKFIN)
	default y
	# This option is on purpose disabled for now.
	# It will be enabled when we are down to a reasonable number
	# of section mismatch warnings (< 10 for an allyesconfig build)
	help
	  The section mismatch analysis checks if there are illegal
	  references from one section to another section.
	  Linux will during link or during runtime drop some sections
	  and any use of code/data previously in these sections will
	  most likely result in an oops.
	  In the code functions and variables are annotated with
	  __init, __devinit etc. (see full list in include/linux/init.h)
	  which results in the code/data being placed in specific sections.
	  The section mismatch analysis is always done after a full
	  kernel build but enabling this option will in addition
	  do the following:
	  - Add the option -fno-inline-functions-called-once to gcc
	    When inlining a function annotated __init in a non-init
	    function we would lose the section information and thus
	    the analysis would not catch the illegal reference.
	    This option tells gcc to inline less but will also
	    result in a larger kernel.
	  - Run the section mismatch analysis for each module/built-in.o
	    When we run the section mismatch analysis on vmlinux.o we
	    lose valueble information about where the mismatch was
	    introduced.
	    Running the analysis for each module/built-in.o file
	    will tell where the mismatch happens much closer to the
	    source. The drawback is that we will report the same
	    mismatch at least twice.
	  - Enable verbose reporting from modpost to help solving
	    the section mismatches reported.

config DEBUG_KERNEL
	bool "Kernel debugging"
	help
	  Say Y here if you are developing drivers or trying to debug and
	  identify kernel problems.

config DEBUG_SHIRQ
	bool "Debug shared IRQ handlers"
	depends on DEBUG_KERNEL && GENERIC_HARDIRQS
	help
	  Enable this to generate a spurious interrupt as soon as a shared
	  interrupt handler is registered, and just before one is deregistered.
	  Drivers ought to be able to handle interrupts coming in at those
	  points; some don't and need to be caught.

config LOCKUP_DETECTOR
	bool "Detect Hard and Soft Lockups"
	depends on DEBUG_KERNEL && !S390
	help
	  Say Y here to enable the kernel to act as a watchdog to detect
	  hard and soft lockups.

	  Softlockups are bugs that cause the kernel to loop in kernel
	  mode for more than 60 seconds, without giving other tasks a
	  chance to run.  The current stack trace is displayed upon
	  detection and the system will stay locked up.

	  Hardlockups are bugs that cause the CPU to loop in kernel mode
	  for more than 60 seconds, without letting other interrupts have a
	  chance to run.  The current stack trace is displayed upon detection
	  and the system will stay locked up.

	  The overhead should be minimal.  A periodic hrtimer runs to
	  generate interrupts and kick the watchdog task every 10-12 seconds.
	  An NMI is generated every 60 seconds or so to check for hardlockups.

config HARDLOCKUP_DETECTOR
	def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
		 !ARCH_HAS_NMI_WATCHDOG

config BOOTPARAM_SOFTLOCKUP_PANIC
	bool "Panic (Reboot) On Soft Lockups"
	depends on LOCKUP_DETECTOR
	help
	  Say Y here to enable the kernel to panic on "soft lockups",