1 .. SPDX-License-Identifier: GPL-2.0
2 .. include:: <isonum.txt>
3
4 =====================
5 ACPICA Trace Facility
6 =====================
7
8 :Copyright: |copy| 2015, Intel Corporation
9 :Author: Lv Zheng <lv.zheng@intel.com>
10
11
12 Abstract
13 ========
14 This document describes the functions and the
15 method tracing facility.
16
17 Functionalities and usage examples
18 ==================================
19
20 ACPICA provides method tracing capability. And
21 currently implemented using this capability.
22
23 Log reducer
24 -----------
25
26 ACPICA subsystem provides debugging outputs wh
27 enabled. The debugging messages which are depl
28 ACPI_DEBUG_PRINT() macro can be reduced at 2 l
29 level (known as debug layer, configured via
30 /sys/module/acpi/parameters/debug_layer) and p
31 debug level, configured via /sys/module/acpi/p
32
33 But when the particular layer/level is applied
34 evaluations, the quantity of the debugging out
35 large to be put into the kernel log buffer. Th
36 to only enable the particular debug layer/leve
37 logs when the control method evaluation is sta
38 detailed logging when the control method evalu
39
40 The following command examples illustrate the
41 functionality:
42
43 a. Filter out the debug layer/level matched lo
44 are being evaluated::
45
46 # cd /sys/module/acpi/parameters
47 # echo "0xXXXXXXXX" > trace_debug_layer
48 # echo "0xYYYYYYYY" > trace_debug_level
49 # echo "enable" > trace_state
50
51 b. Filter out the debug layer/level matched lo
52 control method is being evaluated::
53
54 # cd /sys/module/acpi/parameters
55 # echo "0xXXXXXXXX" > trace_debug_layer
56 # echo "0xYYYYYYYY" > trace_debug_level
57 # echo "\PPPP.AAAA.TTTT.HHHH" > trace_me
58 # echo "method" > /sys/module/acpi/param
59
60 c. Filter out the debug layer/level matched lo
61 control method is being evaluated for the f
62
63 # cd /sys/module/acpi/parameters
64 # echo "0xXXXXXXXX" > trace_debug_layer
65 # echo "0xYYYYYYYY" > trace_debug_level
66 # echo "\PPPP.AAAA.TTTT.HHHH" > trace_me
67 # echo "method-once" > /sys/module/acpi/
68
69 Where:
70 0xXXXXXXXX/0xYYYYYYYY
71 Refer to Documentation/firmware-guide/acp
72 masking values.
73 \PPPP.AAAA.TTTT.HHHH
74 Full path of a control method that can be
75 It needn't be an entry of a control metho
76
77 AML tracer
78 ----------
79
80 There are special log entries added by the met
81 the "trace points" the AML interpreter starts/
82 method, or an AML opcode. Note that the format
83 subject to change::
84
85 [ 0.186427] exdebug-0398 ex_trace_poin
86 [ 0.186630] exdebug-0398 ex_trace_poin
87 [ 0.186820] exdebug-0398 ex_trace_poin
88 [ 0.187010] exdebug-0398 ex_trace_poin
89 [ 0.187214] exdebug-0398 ex_trace_poin
90 [ 0.187407] exdebug-0398 ex_trace_poin
91 [ 0.187594] exdebug-0398 ex_trace_poin
92 [ 0.187789] exdebug-0398 ex_trace_poin
93 [ 0.187980] exdebug-0398 ex_trace_poin
94 [ 0.188146] exdebug-0398 ex_trace_poin
95 [ 0.188334] exdebug-0398 ex_trace_poin
96 [ 0.188524] exdebug-0398 ex_trace_poin
97 [ 0.188712] exdebug-0398 ex_trace_poin
98 [ 0.188903] exdebug-0398 ex_trace_poin
99
100 Developers can utilize these special log entri
101 interpretation, thus can aid issue debugging a
102 that, as the "AML tracer" logs are implemented
103 macro, CONFIG_ACPI_DEBUG is also required to b
104 "AML tracer" logs.
105
106 The following command examples illustrate the
107 functionality:
108
109 a. Filter out the method start/stop "AML trace
110 methods are being evaluated::
111
112 # cd /sys/module/acpi/parameters
113 # echo "0x80" > trace_debug_layer
114 # echo "0x10" > trace_debug_level
115 # echo "enable" > trace_state
116
117 b. Filter out the method start/stop "AML trace
118 control method is being evaluated::
119
120 # cd /sys/module/acpi/parameters
121 # echo "0x80" > trace_debug_layer
122 # echo "0x10" > trace_debug_level
123 # echo "\PPPP.AAAA.TTTT.HHHH" > trace_me
124 # echo "method" > trace_state
125
126 c. Filter out the method start/stop "AML trace
127 control method is being evaluated for the f
128
129 # cd /sys/module/acpi/parameters
130 # echo "0x80" > trace_debug_layer
131 # echo "0x10" > trace_debug_level
132 # echo "\PPPP.AAAA.TTTT.HHHH" > trace_me
133 # echo "method-once" > trace_state
134
135 d. Filter out the method/opcode start/stop "AM
136 specified control method is being evaluated
137
138 # cd /sys/module/acpi/parameters
139 # echo "0x80" > trace_debug_layer
140 # echo "0x10" > trace_debug_level
141 # echo "\PPPP.AAAA.TTTT.HHHH" > trace_me
142 # echo "opcode" > trace_state
143
144 e. Filter out the method/opcode start/stop "AM
145 specified control method is being evaluated
146
147 # cd /sys/module/acpi/parameters
148 # echo "0x80" > trace_debug_layer
149 # echo "0x10" > trace_debug_level
150 # echo "\PPPP.AAAA.TTTT.HHHH" > trace_me
151 # echo "opcode-opcode" > trace_state
152
153 Note that all above method tracing facility re
154 be used as the boot parameters, for example::
155
156 acpi.trace_debug_layer=0x80 acpi.trace_debu
157 acpi.trace_method_name=\_SB.LID0._LID acpi.
158
159
160 Interface descriptions
161 ======================
162
163 All method tracing functions can be configured
164 parameters that are accessible at /sys/module/
165
166 trace_method_name
167 The full path of the AML method that the use
168
169 Note that the full path shouldn't contain th
170 name segments but may contain "\" to form an
171
172 trace_debug_layer
173 The temporary debug_layer used when the trac
174
175 Using ACPI_EXECUTER (0x80) by default, which
176 used to match all "AML tracer" logs.
177
178 trace_debug_level
179 The temporary debug_level used when the trac
180
181 Using ACPI_LV_TRACE_POINT (0x10) by default,
182 debug_level used to match all "AML tracer" l
183
184 trace_state
185 The status of the tracing feature.
186
187 Users can enable/disable this debug tracing
188 the following command::
189
190 # echo string > /sys/module/acpi/parameters
191
192 Where "string" should be one of the following:
193
194 "disable"
195 Disable the method tracing feature.
196
197 "enable"
198 Enable the method tracing feature.
199
200 ACPICA debugging messages matching "trace_de
201 during any method execution will be logged.
202
203 "method"
204 Enable the method tracing feature.
205
206 ACPICA debugging messages matching "trace_de
207 during method execution of "trace_method_nam
208
209 "method-once"
210 Enable the method tracing feature.
211
212 ACPICA debugging messages matching "trace_de
213 during method execution of "trace_method_nam
214
215 "opcode"
216 Enable the method tracing feature.
217
218 ACPICA debugging messages matching "trace_de
219 during method/opcode execution of "trace_met
220
221 "opcode-once"
222 Enable the method tracing feature.
223
224 ACPICA debugging messages matching "trace_de
225 during method/opcode execution of "trace_met
226 once.
227
228 Note that, the difference between the "enable"
229 enabling options are:
230
231 1. When "enable" is specified, since
232 "trace_debug_layer/trace_debug_level" shall
233 method evaluations, after configuring "trac
234 "trace_method_name" will be reset to NULL.
235 2. When "method/opcode" is specified, if
236 "trace_method_name" is NULL when "trace_sta
237 these options, the "trace_debug_layer/trace
238 apply to all control method evaluations.
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.