1obpsym(1M) System Administration Commands obpsym(1M)
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6 obpsym - Kernel Symbolic Debugging for OpenBoot Firmware
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9 modload -p misc/obpsym
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13 obpsym is a kernel module that installs OpenBoot callback handlers that
14 provide kernel symbol information to OpenBoot. OpenBoot firmware user
15 interface commands use the callbacks to convert numeric addresses to
16 kernel symbol names for display purposes, and to convert kernel symbol
17 names to numeric literals allowing symbolic names to be used as input
18 arguments to user interface commands.
19 Once obpsym is installed, kernel symbolic names may be used anywhere at
22 the OpenBoot firmware's user interface command prompt in place of a
23 literal (numeric) string. For example, if obpsym is installed, the
24 OpenBoot firmware commands ctrace and dis typically display symbolic
25 names and offsets in the form modname:symbolname + offset. User inter‐
26 face Commands such as dis can be given a kernel symbolic name such as
27 ufs:ufs_mount instead of a numeric address.
28 Placing the command
31 forceload: misc/obpsym
34 into the system(4) file forces the kernel module misc/obpsym to be
37 loaded and activates the kernel callbacks during the kernel startup
38 sequence.
39 obpsym may be useful as a kernel debugger in situations where other
42 kernel debuggers are not useful. For example, on SPARC machines, if
43 obpsym is loaded, you may be able to use the OpenBoot firmware's ctrace
44 command to display symbolic names in the stack backtrace after a watch‐
45 dog reset.
46 Kernel Symbolic Name Syntax
48 The syntax for a kernel symbolic name is:
49 [ module-name : ] symbol-name
52 Where module-name is the name of the kernel module that the symbol sym‐
55 bol-name appears in. A NULL module name is taken as "all modules, in no
56 particular order" by obpsym. The module name unix is equivalent to a
57 NULL module name, so that conflicts with words defined in the
58 firmware's vocabulary can be avoided.
59 Typically, OpenBoot firmware reads a word from the input stream and
62 looks the word up in its internal vocabulary before checking if the
63 word is a literal. Thus, kernel symbols, such as reset may be given as
64 unix:reset to avoid the unexpected side effect of the firmware finding
65 and executing a matching word in its vocabulary.
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68 /etc/system
69 system configuration information file
71 /platform/platform-name/kernel/misc/obpsym
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79 See attributes(5) for descriptions of the following attributes:
80 ┌─────────────────────────────┬─────────────────────────────┐
85 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
86 ├─────────────────────────────┼─────────────────────────────┤
87 │Availability │SUNWcar │
88 └─────────────────────────────┴─────────────────────────────┘
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91 kadb(1M), kernel(1M), modload(1M), modunload(1M), uname(1), system(4),
92 attributes(5)
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98 Some OpenBoot firmware user interface commands may use system resources
99 incompatibly with the way they are used by the Unix kernel. These com‐
100 mands and the use of this feature as a kernel debugger may cause inter‐
101 actions that the Unix kernel is not prepared to deal with. If this
102 occurs, the Unix kernel and/or the OpenBoot firmware user interface
103 commands may react unpredictably and may panic the system, or may hang
104 or may cause other unpredictable results. For these reasons, the use of
105 this feature is only minimally supported and recommended to be used
106 only as a kernel debugger of "last resort".
107 If a breakpoint or watchpoint is triggered while the console frame buf‐
110 fer is powered off, the system can crash and be left in a state from
111 which it is difficult to recover. If one of these is triggered while
112 the monitor is powered off, you will not be able to see the debugger
113 output.
114
116 platform-name can be found using the -i option of uname(1)
117 obpsym is supported only on architectures that support OpenBoot
120 firmware.
121 On some systems, OpenBoot must be completely RAM resident so the obpsym
124 symbol callback support can be added to the firmware, if the firmware
125 doesn't include support for the symbol callbacks. On these systems,
126 obpsym may complain that it requires that "you must use ramforth to use
127 this module".
128 See the for details on how to use the ramforth command, how to place
131 the command into nvramrc, and how to set use-nvramrc? to true. On sys‐
132 tems with version 1.x OpenBoot firmware, nvramrc doesn't exist, and the
133 ramforth command must be typed manually after each reset, in order to
134 use this module.
135 Once installed, the symbol table callbacks can be disabled by using the
138 following OpenBoot firmware command:
139 0 0 set-symbol-lookup
142SunOS 5.11 13 Dec 2001 obpsym(1M)