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 66config DEBUG_STACK_USAGE 67 bool "Enable stack utilization instrumentation" 68 depends on DEBUG_KERNEL 69 help 70 Enables the display of the minimum amount of free stack which each 71 task has ever had available in the sysrq-T output. 72 73# These options are only for real kernel hackers who want to get their hands dirty. 74config DEBUG_LL 75 bool "Kernel low-level debugging functions" 76 depends on DEBUG_KERNEL 77 help 78 Say Y here to include definitions of printascii, printch, printhex 79 in the kernel. This is helpful if you are debugging code that 80 executes before the console is initialized. 81 82config EARLY_PRINTK 83 bool "Early printk" 84 depends on DEBUG_LL 85 help 86 Say Y here if you want to have an early console using the 87 kernel low-level debugging functions. Add earlyprintk to your 88 kernel parameters to enable this console. 89 90config DEBUG_ICEDCC 91 bool "Kernel low-level debugging via EmbeddedICE DCC channel" 92 depends on DEBUG_LL 93 help 94 Say Y here if you want the debug print routines to direct their 95 output to the EmbeddedICE macrocell's DCC channel using 96 co-processor 14. This is known to work on the ARM9 style ICE 97 channel and on the XScale with the PEEDI. 98 99 It does include a timeout to ensure that the system does not 100 totally freeze when there is nothing connected to read. 101 102config OC_ETM 103 bool "On-chip ETM and ETB" 104 select ARM_AMBA 105 help 106 Enables the on-chip embedded trace macrocell and embedded trace 107 buffer driver that will allow you to collect traces of the 108 kernel code. 109 110config DEBUG_DC21285_PORT 111 bool "Kernel low-level debugging messages via footbridge serial port" 112 depends on DEBUG_LL && FOOTBRIDGE 113 help 114 Say Y here if you want the debug print routines to direct their 115 output to the serial port in the DC21285 (Footbridge). Saying N 116 will cause the debug messages to appear on the first 16550 117 serial port. 118 119config DEBUG_CLPS711X_UART2 120 bool "Kernel low-level debugging messages via UART2" 121 depends on DEBUG_LL && ARCH_CLPS711X 122 help 123 Say Y here if you want the debug print routines to direct their 124 output to the second serial port on these devices. Saying N will 125 cause the debug messages to appear on the first serial port. 126 127config DEBUG_S3C_UART 128 depends on PLAT_SAMSUNG 129 int "S3C UART to use for low-level debug" 130 default "0" 131 help 132 Choice for UART for kernel low-level using S3C UARTS, 133 should be between zero and two. The port must have been 134 initialised by the boot-loader before use. 135 136 The uncompressor code port configuration is now handled 137 by CONFIG_S3C_LOWLEVEL_UART_PORT. 138 139endmenu 140