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