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 || FUNCTION_GRAPH_TRACER 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 (EXPERIMENTAL)" 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 66# These options are only for real kernel hackers who want to get their hands dirty. 67config DEBUG_LL 68 bool "Kernel low-level debugging functions (read help!)" 69 depends on DEBUG_KERNEL 70 help 71 Say Y here to include definitions of printascii, printch, printhex 72 in the kernel. This is helpful if you are debugging code that 73 executes before the console is initialized. 74 75 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 80choice 81 prompt "Kernel low-level debugging port" 82 depends on DEBUG_LL 83 84 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 92 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. 99 100 Note that the system will appear to hang during boot if there 101 is nothing connected to read from the DCC. 102 103 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. 109 110 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). 116 117 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. 123 124 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. 130 131endchoice 132 133config EARLY_PRINTK 134 bool "Early printk" 135 depends on DEBUG_LL 136 help 137 Say Y here if you want to have an early console using the 138 kernel low-level debugging functions. Add earlyprintk to your 139 kernel parameters to enable this console. 140 141config OC_ETM 142 bool "On-chip ETM and ETB" 143 depends on ARM_AMBA 144 help 145 Enables the on-chip embedded trace macrocell and embedded trace 146 buffer driver that will allow you to collect traces of the 147 kernel code. 148 149config DEBUG_S3C_UART 150 depends on PLAT_SAMSUNG 151 int "S3C UART to use for low-level debug" 152 default "0" 153 help 154 Choice for UART for kernel low-level using S3C UARTS, 155 should be between zero and two. The port must have been 156 initialised by the boot-loader before use. 157 158 The uncompressor code port configuration is now handled 159 by CONFIG_S3C_LOWLEVEL_UART_PORT. 160 161config ARM_KPROBES_TEST 162 tristate "Kprobes test module" 163 depends on KPROBES && MODULES 164 help 165 Perform tests of kprobes API and instruction set simulation. 166 167endmenu 168