Root/arch/arm/Kconfig.debug

1menu "Kernel hacking"
2
3source "lib/Kconfig.debug"
4
5config STRICT_DEVMEM
6    bool "Filter access to /dev/mem"
7    depends on MMU
8    ---help---
9      If this option is disabled, you allow userspace (root) access to all
10      of memory, including kernel and userspace memory. Accidental
11      access to this is obviously disastrous, but specific access can
12      be used by people debugging the kernel.
13
14      If this option is switched on, the /dev/mem file only allows
15      userspace access to memory mapped peripherals.
16
17          If in doubt, say Y.
18
19# RMK wants arm kernels compiled with frame pointers or stack unwinding.
20# If you know what you are doing and are willing to live without stack
21# traces, you can get a slightly smaller kernel by setting this option to
22# n, but then RMK will have to kill you ;).
23config FRAME_POINTER
24    bool
25    depends on !THUMB2_KERNEL
26    default y if !ARM_UNWIND
27    help
28      If you say N here, the resulting kernel will be slightly smaller and
29      faster. However, if neither FRAME_POINTER nor ARM_UNWIND are enabled,
30      when a problem occurs with the kernel, the information that is
31      reported is severely limited.
32
33config ARM_UNWIND
34    bool "Enable stack unwinding support"
35    depends on AEABI && EXPERIMENTAL
36    default y
37    help
38      This option enables stack unwinding support in the kernel
39      using the information automatically generated by the
40      compiler. The resulting kernel image is slightly bigger but
41      the performance is not affected. Currently, this feature
42      only works with EABI compilers. If unsure say Y.
43
44config OLD_MCOUNT
45    bool
46    depends on FUNCTION_TRACER && FRAME_POINTER
47    default y
48
49config DEBUG_USER
50    bool "Verbose user fault messages"
51    help
52      When a user program crashes due to an exception, the kernel can
53      print a brief message explaining what the problem was. This is
54      sometimes helpful for debugging but serves no purpose on a
55      production system. Most people should say N here.
56
57      In addition, you need to pass user_debug=N on the kernel command
58      line to enable this feature. N consists of the sum of:
59
60          1 - undefined instruction events
61          2 - system calls
62          4 - invalid data aborts
63          8 - SIGSEGV faults
64         16 - SIGBUS faults
65
66config DEBUG_ERRORS
67    bool "Verbose kernel error messages"
68    depends on DEBUG_KERNEL
69    help
70      This option controls verbose debugging information which can be
71      printed when the kernel detects an internal error. This debugging
72      information is useful to kernel hackers when tracking down problems,
73      but mostly meaningless to other people. It's safe to say Y unless
74      you are concerned with the code size or don't want to see these
75      messages.
76
77config DEBUG_STACK_USAGE
78    bool "Enable stack utilization instrumentation"
79    depends on DEBUG_KERNEL
80    help
81      Enables the display of the minimum amount of free stack which each
82      task has ever had available in the sysrq-T output.
83
84# These options are only for real kernel hackers who want to get their hands dirty.
85config DEBUG_LL
86    bool "Kernel low-level debugging functions"
87    depends on DEBUG_KERNEL
88    help
89      Say Y here to include definitions of printascii, printch, printhex
90      in the kernel. This is helpful if you are debugging code that
91      executes before the console is initialized.
92
93config EARLY_PRINTK
94    bool "Early printk"
95    depends on DEBUG_LL
96    help
97      Say Y here if you want to have an early console using the
98      kernel low-level debugging functions. Add earlyprintk to your
99      kernel parameters to enable this console.
100
101config DEBUG_ICEDCC
102    bool "Kernel low-level debugging via EmbeddedICE DCC channel"
103    depends on DEBUG_LL
104    help
105      Say Y here if you want the debug print routines to direct their
106      output to the EmbeddedICE macrocell's DCC channel using
107      co-processor 14. This is known to work on the ARM9 style ICE
108      channel and on the XScale with the PEEDI.
109
110      It does include a timeout to ensure that the system does not
111      totally freeze when there is nothing connected to read.
112
113config OC_ETM
114    bool "On-chip ETM and ETB"
115    select ARM_AMBA
116    help
117      Enables the on-chip embedded trace macrocell and embedded trace
118      buffer driver that will allow you to collect traces of the
119      kernel code.
120
121config DEBUG_DC21285_PORT
122    bool "Kernel low-level debugging messages via footbridge serial port"
123    depends on DEBUG_LL && FOOTBRIDGE
124    help
125      Say Y here if you want the debug print routines to direct their
126      output to the serial port in the DC21285 (Footbridge). Saying N
127      will cause the debug messages to appear on the first 16550
128      serial port.
129
130config DEBUG_CLPS711X_UART2
131    bool "Kernel low-level debugging messages via UART2"
132    depends on DEBUG_LL && ARCH_CLPS711X
133    help
134      Say Y here if you want the debug print routines to direct their
135      output to the second serial port on these devices. Saying N will
136      cause the debug messages to appear on the first serial port.
137
138config DEBUG_S3C_UART
139    depends on PLAT_SAMSUNG
140    int "S3C UART to use for low-level debug"
141    default "0"
142    help
143      Choice for UART for kernel low-level using S3C UARTS,
144      should be between zero and two. The port must have been
145      initialised by the boot-loader before use.
146
147      The uncompressor code port configuration is now handled
148      by CONFIG_S3C_LOWLEVEL_UART_PORT.
149
150endmenu
151

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