arch/arm/Kconfig.debug

   1 menu "Kernel hacking"
   2
   3 source "lib/Kconfig.debug"
   4
   5 config 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 ;).
  23 config 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
  33 config 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
  44 config OLD_MCOUNT
  45         bool
  46         depends on FUNCTION_TRACER && FRAME_POINTER
  47         default y
  48
  49 config 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 config 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
  77 config 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.
  85 config 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
  93 config 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
 101 config 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
 113 config 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
 121 config 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
 130 config 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
 138 config 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
 150 endmenu