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Linus Torvalds1da177e2005-04-16 15:20:36 -07001menu "Kernel hacking"
2
3source "lib/Kconfig.debug"
4
Nicolas Pitre087aaff2010-09-22 18:34:36 -04005config 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
Catalin Marinasadf8b372009-02-12 13:56:34 +010019# RMK wants arm kernels compiled with frame pointers or stack unwinding.
Linus Torvalds1da177e2005-04-16 15:20:36 -070020# 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
Catalin Marinas16c79652009-07-24 12:33:02 +010025 depends on !THUMB2_KERNEL
Rabin Vincent0e341af2010-11-06 23:03:53 +053026 default y if !ARM_UNWIND || FUNCTION_GRAPH_TRACER
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 help
28 If you say N here, the resulting kernel will be slightly smaller and
Catalin Marinasadf8b372009-02-12 13:56:34 +010029 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
Russell King4a50bfe2010-12-05 23:06:22 +000034 bool "Enable stack unwinding support (EXPERIMENTAL)"
Catalin Marinasadf8b372009-02-12 13:56:34 +010035 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.
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
Rabin Vincent09bfafa2010-08-10 19:32:37 +010044config OLD_MCOUNT
45 bool
46 depends on FUNCTION_TRACER && FRAME_POINTER
47 default y
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049config 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070066# These options are only for real kernel hackers who want to get their hands dirty.
67config DEBUG_LL
Will Deacon4f5ef922011-09-01 19:04:44 +010068 bool "Kernel low-level debugging functions (read help!)"
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 depends on DEBUG_KERNEL
70 help
Russell King35efb602005-09-09 15:57:17 +010071 Say Y here to include definitions of printascii, printch, printhex
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 in the kernel. This is helpful if you are debugging code that
73 executes before the console is initialized.
74
Will Deacon4f5ef922011-09-01 19:04:44 +010075 Note that selecting this option will limit the kernel to a single
76 UART definition, as specified below. Attempting to boot the kernel
77 image on a different platform *will not work*, so this option should
78 not be enabled for kernels that are intended to be portable.
79
Will Deacon17916b22011-09-01 18:58:51 +010080choice
81 prompt "Kernel low-level debugging port"
82 depends on DEBUG_LL
83
Will Deaconf73765f2011-10-03 18:29:03 +010084 config DEBUG_LL_UART_NONE
85 bool "No low-level debugging UART"
86 help
87 Say Y here if your platform doesn't provide a UART option
88 below. This relies on your platform choosing the right UART
89 definition internally in order for low-level debugging to
90 work.
91
Stephen Boyd6996f422011-09-22 20:28:36 +010092 config DEBUG_ICEDCC
93 bool "Kernel low-level debugging via EmbeddedICE DCC channel"
94 help
95 Say Y here if you want the debug print routines to direct
96 their output to the EmbeddedICE macrocell's DCC channel using
97 co-processor 14. This is known to work on the ARM9 style ICE
98 channel and on the XScale with the PEEDI.
99
Will Deaconf73765f2011-10-03 18:29:03 +0100100 Note that the system will appear to hang during boot if there
101 is nothing connected to read from the DCC.
Stephen Boyd164acf92011-09-22 20:28:35 +0100102
103 config DEBUG_FOOTBRIDGE_COM1
104 bool "Kernel low-level debugging messages via footbridge 8250 at PCI COM1"
105 depends on FOOTBRIDGE
106 help
107 Say Y here if you want the debug print routines to direct
108 their output to the 8250 at PCI COM1.
109
Will Deacon17916b22011-09-01 18:58:51 +0100110 config DEBUG_DC21285_PORT
111 bool "Kernel low-level debugging messages via footbridge serial port"
112 depends on FOOTBRIDGE
113 help
114 Say Y here if you want the debug print routines to direct
115 their output to the serial port in the DC21285 (Footbridge).
Stephen Boyd164acf92011-09-22 20:28:35 +0100116
117 config DEBUG_CLPS711X_UART1
118 bool "Kernel low-level debugging messages via UART1"
119 depends on ARCH_CLPS711X
120 help
121 Say Y here if you want the debug print routines to direct
122 their output to the first serial port on these devices.
Will Deacon17916b22011-09-01 18:58:51 +0100123
124 config DEBUG_CLPS711X_UART2
125 bool "Kernel low-level debugging messages via UART2"
126 depends on ARCH_CLPS711X
127 help
128 Say Y here if you want the debug print routines to direct
129 their output to the second serial port on these devices.
Will Deacon17916b22011-09-01 18:58:51 +0100130
Rob Herring220e6cf2011-06-07 10:02:55 -0500131 config DEBUG_HIGHBANK_UART
132 bool "Kernel low-level debugging messages via Highbank UART"
133 depends on ARCH_HIGHBANK
134 help
135 Say Y here if you want the debug print routines to direct
136 their output to the UART on Highbank based devices.
137
Will Deacon17916b22011-09-01 18:58:51 +0100138endchoice
139
Catalin Marinas93fd03a2009-12-09 10:02:18 +0000140config EARLY_PRINTK
141 bool "Early printk"
142 depends on DEBUG_LL
143 help
144 Say Y here if you want to have an early console using the
145 kernel low-level debugging functions. Add earlyprintk to your
146 kernel parameters to enable this console.
147
Alexander Shishkinc5d6c772009-12-01 14:00:51 +0100148config OC_ETM
149 bool "On-chip ETM and ETB"
150 select ARM_AMBA
151 help
152 Enables the on-chip embedded trace macrocell and embedded trace
153 buffer driver that will allow you to collect traces of the
154 kernel code.
155
Ben Dooks3ec20522007-07-22 16:12:04 +0100156config DEBUG_S3C_UART
Ben Dooks89f1fa02010-01-29 09:02:17 +0000157 depends on PLAT_SAMSUNG
Ben Dooks3ec20522007-07-22 16:12:04 +0100158 int "S3C UART to use for low-level debug"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 default "0"
160 help
Ben Dooks3ec20522007-07-22 16:12:04 +0100161 Choice for UART for kernel low-level using S3C UARTS,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 should be between zero and two. The port must have been
Egry Gaborc41045a2006-06-04 21:22:11 +0100163 initialised by the boot-loader before use.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164
165 The uncompressor code port configuration is now handled
Ben Dooksc7657842007-07-22 16:11:20 +0100166 by CONFIG_S3C_LOWLEVEL_UART_PORT.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
Jon Medhurst4189bc72011-08-27 12:36:58 +0100168config ARM_KPROBES_TEST
169 tristate "Kprobes test module"
170 depends on KPROBES && MODULES
171 help
172 Perform tests of kprobes API and instruction set simulation.
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174endmenu