obpsym(1M)						  System Administration Commands						obpsym(1M)

NAME

       obpsym - Kernel Symbolic Debugging for OpenBoot Firmware

SYNOPSIS

       modload -p misc/obpsym

DESCRIPTION

       obpsym  is  a  kernel module that installs OpenBoot callback handlers that provide kernel symbol information to OpenBoot. OpenBoot firmware
       user interface commands use the callbacks to convert numeric addresses to kernel symbol names for display purposes, and to  convert  kernel
       symbol names to numeric literals allowing symbolic names to be used as input arguments to user interface commands.

       Once obpsym is installed, kernel symbolic names may be used anywhere at the OpenBoot firmware's user interface command prompt in place of a
       literal (numeric) string. For example, if obpsym is installed, the OpenBoot firmware commands ctrace and  dis  typically  display  symbolic
       names  and offsets in the form modname:symbolname + offset. User interface Commands such as dis can be given a kernel symbolic name such as
       ufs:ufs_mount instead of a numeric address.

       Placing the command

	      forceload: misc/obpsym

       into the system(4) file forces the kernel module misc/obpsym to be loaded and activates the kernel  callbacks  during  the  kernel  startup
       sequence.

       obpsym  may  be	useful	as a kernel debugger in situations where other kernel debuggers are not useful. For example, on SPARC machines, if
       obpsym is loaded, you may be able to use the OpenBoot firmware's ctrace command to display symbolic names in the stack  backtrace  after  a
       watchdog reset.

   Kernel Symbolic Name Syntax
       The syntax for a kernel symbolic name is:

	       [ module-name : ] symbol-name

       Where  module-name is the name of the kernel module that the symbol symbol-name appears in. A NULL module name is taken as "all modules, in
       no particular order" by obpsym. The module name unix is equivalent to a NULL module name, so that  conflicts  with  words  defined  in  the
       firmware's vocabulary can be avoided.

       Typically,  OpenBoot  firmware  reads  a word from the input stream and looks the word up in its internal vocabulary before checking if the
       word is a literal. Thus, kernel symbols, such as reset may be given as unix:reset to avoid the unexpected side effect of the firmware find-
       ing and executing a matching word in its vocabulary.

FILES

       /etc/system

	   system configuration information file

       /platform/platform-name/kernel/misc/obpsym

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcar			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       kadb(1M), kernel(1M), modload(1M), modunload(1M), uname(1), system(4), attributes(5)

       OpenBoot 2.x Command Reference Manual

WARNINGS

       Some  OpenBoot  firmware user interface commands may use system resources incompatibly with the way they are used by the Unix kernel. These
       commands and the use of this feature as a kernel debugger may cause interactions that the Unix kernel is not prepared to deal with. If this
       occurs,	the Unix kernel and/or the OpenBoot firmware user interface commands may react unpredictably and may panic the system, or may hang
       or may cause other unpredictable results. For these reasons, the use of this feature is only minimally supported and recommended to be used
       only as a kernel debugger of "last resort".

       If  a breakpoint or watchpoint is triggered while the console frame buffer is powered off, the system can crash and be left in a state from
       which it is difficult to recover. If one of these is triggered while the monitor is powered off, you will not be able to see  the  debugger
       output.

NOTES

       platform-name can be found using the -i option of uname(1)

       obpsym is supported only on architectures that support OpenBoot firmware.

       On  some  systems,  OpenBoot  must  be  completely  RAM resident so the obpsym symbol callback support can be added to the firmware, if the
       firmware doesn't include support for the symbol callbacks. On these systems, obpsym may complain that it requires that "you must  use  ram-
       forth to use this module".

       See  the  OpenBoot  2.x Command Reference Manual for details on how to use the ramforth command, how to place the command into nvramrc, and
       how to set use-nvramrc? to true. On systems with version 1.x OpenBoot firmware, nvramrc doesn't exist, and the  ramforth  command  must	be
       typed manually after each reset, in order to use this module.

       Once installed, the symbol table callbacks can be disabled by using the following OpenBoot firmware command:

	      0 0 set-symbol-lookup

SunOS 5.10							    13 Dec 2001 							obpsym(1M)