menu "Kernel hacking"
source "lib/Kconfig.debug"
config ARM_PTDUMP
bool "Export kernel pagetable layout to userspace via debugfs"
depends on DEBUG_KERNEL
select DEBUG_FS
---help---
Say Y here if you want to show the kernel pagetable layout in a
debugfs file. This information is only useful for kernel developers
who are working in architecture specific areas of the kernel.
It is probably not a good idea to enable this feature in a production
kernel.
If in doubt, say "N"
config STRICT_DEVMEM
bool "Filter access to /dev/mem"
depends on MMU
---help---
If this option is disabled, you allow userspace (root) access to all
of memory, including kernel and userspace memory. Accidental
access to this is obviously disastrous, but specific access can
be used by people debugging the kernel.
If this option is switched on, the /dev/mem file only allows
userspace access to memory mapped peripherals.
If in doubt, say Y.
# RMK wants arm kernels compiled with frame pointers or stack unwinding.
# If you know what you are doing and are willing to live without stack
# traces, you can get a slightly smaller kernel by setting this option to
# n, but then RMK will have to kill you ;).
config FRAME_POINTER
bool
depends on !THUMB2_KERNEL
default y if !ARM_UNWIND || FUNCTION_GRAPH_TRACER
help
If you say N here, the resulting kernel will be slightly smaller and
faster. However, if neither FRAME_POINTER nor ARM_UNWIND are enabled,
when a problem occurs with the kernel, the information that is
reported is severely limited.
config ARM_UNWIND
bool "Enable stack unwinding support (EXPERIMENTAL)"
depends on AEABI
default y
help
This option enables stack unwinding support in the kernel
using the information automatically generated by the
compiler. The resulting kernel image is slightly bigger but
the performance is not affected. Currently, this feature
only works with EABI compilers. If unsure say Y.
config OLD_MCOUNT
bool
depends on FUNCTION_TRACER && FRAME_POINTER
default y
config DEBUG_USER
bool "Verbose user fault messages"
help
When a user program crashes due to an exception, the kernel can
print a brief message explaining what the problem was. This is
sometimes helpful for debugging but serves no purpose on a
production system. Most people should say N here.
In addition, you need to pass user_debug=N on the kernel command
line to enable this feature. N consists of the sum of:
1 - undefined instruction events
2 - system calls
4 - invalid data aborts
8 - SIGSEGV faults
16 - SIGBUS faults
# These options are only for real kernel hackers who want to get their hands dirty.
config DEBUG_LL
bool "Kernel low-level debugging functions (read help!)"
depends on DEBUG_KERNEL
help
Say Y here to include definitions of printascii, printch, printhex
in the kernel. This is helpful if you are debugging code that
executes before the console is initialized.
Note that selecting this option will limit the kernel to a single
UART definition, as specified below. Attempting to boot the kernel
image on a different platform *will not work*, so this option should
not be enabled for kernels that are intended to be portable.
choice
prompt "Kernel low-level debugging port"
depends on DEBUG_LL
config AT91_DEBUG_LL_DBGU0
bool "Kernel low-level debugging on rm9200, 9260/9g20, 9261/9g10 and 9rl"
depends on HAVE_AT91_DBGU0
config AT91_DEBUG_LL_DBGU1
bool "Kernel low-level debugging on 9263 and 9g45"
depends on HAVE_AT91_DBGU1
config AT91_DEBUG_LL_DBGU2
bool "Kernel low-level debugging on sama5d4"
depends on HAVE_AT91_DBGU2
config DEBUG_BCM2835
bool "Kernel low-level debugging on BCM2835 PL011 UART"
depends on ARCH_BCM2835
select DEBUG_UART_PL01X
config DEBUG_BCM_5301X
bool "Kernel low-level debugging on BCM5301X UART1"
depends on ARCH_BCM_5301X
select DEBUG_UART_PL01X
config DEBUG_BCM_KONA_UART
bool "Kernel low-level debugging messages via BCM KONA UART"
depends on ARCH_BCM_MOBILE
select DEBUG_UART_8250
help
Say Y here if you want kernel low-level debugging support
on Broadcom SoC platforms.
This low level debug works for Broadcom
mobile SoCs in the Kona family of chips (e.g. bcm28155,
bcm11351, etc...)
config DEBUG_BCM63XX
bool "Kernel low-level debugging on BCM63XX UART"
depends on ARCH_BCM_63XX
select DEBUG_UART_BCM63XX
config DEBUG_BERLIN_UART
bool "Marvell Berlin SoC Debug UART"
depends on ARCH_BERLIN
select DEBUG_UART_8250
help