# Kconfig - debug configuration options
# Copyright (c) 2015 Wind River Systems, Inc.
# SPDX-License-Identifier: Apache-2.0
menu "Debugging Options"
bool "Build kernel with debugging enabled"
Build a kernel suitable for debugging. Right now, this option
only disables optimization, more debugging variants can be selected
from here to allow more debugging.
bool "Generate stack usage information"
Generate an extra file that specifies the maximum amount of stack used,
on a per-function basis.
bool "Enable stack sentinel"
Store a magic value at the lowest addresses of a thread's stack.
Periodically check that this value is still present and kill the
thread gracefully if it isn't. This is currently checked in four
1) Upon any context switch for the outgoing thread
2) Any hardware interrupt that doesn't context switch, the check is
performed for the interrupted thread
3) When a thread returns from its entry point
4) When a thread calls k_yield() but doesn't context switch
This feature doesn't prevent corruption and the system may be
in an unusable state. However, given the bizarre behavior associated
with stack overflows, knowledge that this is happening is very
This feature is intended for those systems which lack hardware support
for stack overflow protection, or have insufficient system resources
to use that hardware support.
prompt "Send printk() to console"
depends on CONSOLE_HAS_DRIVER
This option directs printk() debugging output to the supported
console device, rather than suppressing the generation
of printk() output entirely. Output is sent immediately, without
any mutual exclusion or buffering.
prompt "printk() buffer size"
depends on PRINTK
depends on USERSPACE
If userspace is enabled, printk() calls are buffered so that we do
not have to make a system call for every character emitted. Specify
the size of this buffer.
prompt "Send stdout to console"
depends on CONSOLE_HAS_DRIVER
This option directs standard output (e.g. printf) to the console
device, rather than suppressing it entirely.
prompt "Send stdout at the earliest stage possible"
This option will enable stdout as early as possible, for debugging
purpose. For instance, in case of STDOUT_CONSOLE being set it will
initialize its driver earlier than normal, in order to get the stdout
sent through the console at the earliest stage possible.
prompt "Enable __ASSERT() macro"
This enables the __ASSERT() macro in the kernel code. If an assertion
fails, the calling thread is put on an infinite tight loop. Since
enabling this adds a significant footprint, it should only be enabled
in a non-production system.
prompt "__ASSERT() level"
range 0 2
depends on ASSERT
This option specifies the assertion level used by the __ASSERT()
macro. It can be set to one of three possible values:
Level 0: off
Level 1: on + warning in every file that includes __assert.h
Level 2: on + no warning
bool "Kernel object tracing (deprecated)"
For backward compatibility only
prompt "Kernel object tracing"
This option enable the feature for tracing kernel objects. This option
is for debug purposes and increases the memory footprint of the kernel.
prompt "Override compiler defaults for -fomit-frame-pointer"
Omitting the frame pointer prevents the compiler from putting the stack
frame pointer into a register. Saves a few instructions in function
prologues/epilogues and frees up a register for general-purpose use,
which can provide good performance improvements on register-constrained
architectures like x86. On some architectures (including x86) omitting
frame pointers impedes debugging as local variables are harder to
locate. At -O1 and above gcc will enable -fomit-frame-pointer
automatically but only if the architecture does not require if for
Choose Y if you want to override the default frame pointer behavior
of your compiler, otherwise choose N.
prompt "Omit frame pointer"
depends on OVERRIDE_FRAME_POINTER_DEFAULT
Choose Y for best performance. On some architectures (including x86)
this will favor code size and performance over debugability.
Choose N in you wish to retain the frame pointer. This option may
be useful if your application uses runtime backtracing and does not
support parsing unwind tables.
If unsure, disable OVERRIDE_FRAME_POINTER_DEFAULT to allow the compiler
to adopt sensible defaults for your architecture.
# Generic Debugging Options
bool "Enable system debugging information"
depends on X86
This option enables the addition of various information that can be used
by debuggers in debugging the system.
NOTE: Does not currently work with the x86 IAMCU ABI.
# Miscellaneous debugging options
prompt "OpenOCD support [EXPERIMENTAL]"
This option exports an array of offsets to kernel structs, used by
OpenOCD to determine the state of running threads. (This option
selects CONFIG_THREAD_MONITOR, so all of its caveats are implied.)