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Commit 5ee00bd4691e7364bb7b62e2068d473cd5cb9320

Authored by Joerg Roedel
1 parent 0bd5c4f7c8
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

dma-debug: add Kconfig entry 

Impact: add a Kconfig entry for DMA-API debugging

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

Showing 2 changed files with 13 additions and 0 deletions Inline Diff

1 # 1 #
2 # General architecture dependent options 2 # General architecture dependent options
3 # 3 #
4 4
5 config OPROFILE 5 config OPROFILE
6 tristate "OProfile system profiling (EXPERIMENTAL)" 6 tristate "OProfile system profiling (EXPERIMENTAL)"
7 depends on PROFILING 7 depends on PROFILING
8 depends on HAVE_OPROFILE 8 depends on HAVE_OPROFILE
9 select TRACING 9 select TRACING
10 select RING_BUFFER 10 select RING_BUFFER
11 help 11 help
12 OProfile is a profiling system capable of profiling the 12 OProfile is a profiling system capable of profiling the
13 whole system, include the kernel, kernel modules, libraries, 13 whole system, include the kernel, kernel modules, libraries,
14 and applications. 14 and applications.
15 15
16 If unsure, say N. 16 If unsure, say N.
17 17
18 config OPROFILE_IBS 18 config OPROFILE_IBS
19 bool "OProfile AMD IBS support (EXPERIMENTAL)" 19 bool "OProfile AMD IBS support (EXPERIMENTAL)"
20 default n 20 default n
21 depends on OPROFILE && SMP && X86 21 depends on OPROFILE && SMP && X86
22 help 22 help
23 Instruction-Based Sampling (IBS) is a new profiling 23 Instruction-Based Sampling (IBS) is a new profiling
24 technique that provides rich, precise program performance 24 technique that provides rich, precise program performance
25 information. IBS is introduced by AMD Family10h processors 25 information. IBS is introduced by AMD Family10h processors
26 (AMD Opteron Quad-Core processor "Barcelona") to overcome 26 (AMD Opteron Quad-Core processor "Barcelona") to overcome
27 the limitations of conventional performance counter 27 the limitations of conventional performance counter
28 sampling. 28 sampling.
29 29
30 If unsure, say N. 30 If unsure, say N.
31 31
32 config HAVE_OPROFILE 32 config HAVE_OPROFILE
33 bool 33 bool
34 34
35 config KPROBES 35 config KPROBES
36 bool "Kprobes" 36 bool "Kprobes"
37 depends on KALLSYMS && MODULES 37 depends on KALLSYMS && MODULES
38 depends on HAVE_KPROBES 38 depends on HAVE_KPROBES
39 help 39 help
40 Kprobes allows you to trap at almost any kernel address and 40 Kprobes allows you to trap at almost any kernel address and
41 execute a callback function. register_kprobe() establishes 41 execute a callback function. register_kprobe() establishes
42 a probepoint and specifies the callback. Kprobes is useful 42 a probepoint and specifies the callback. Kprobes is useful
43 for kernel debugging, non-intrusive instrumentation and testing. 43 for kernel debugging, non-intrusive instrumentation and testing.
44 If in doubt, say "N". 44 If in doubt, say "N".
45 45
46 config HAVE_EFFICIENT_UNALIGNED_ACCESS 46 config HAVE_EFFICIENT_UNALIGNED_ACCESS
47 bool 47 bool
48 help 48 help
49 Some architectures are unable to perform unaligned accesses 49 Some architectures are unable to perform unaligned accesses
50 without the use of get_unaligned/put_unaligned. Others are 50 without the use of get_unaligned/put_unaligned. Others are
51 unable to perform such accesses efficiently (e.g. trap on 51 unable to perform such accesses efficiently (e.g. trap on
52 unaligned access and require fixing it up in the exception 52 unaligned access and require fixing it up in the exception
53 handler.) 53 handler.)
54 54
55 This symbol should be selected by an architecture if it can 55 This symbol should be selected by an architecture if it can
56 perform unaligned accesses efficiently to allow different 56 perform unaligned accesses efficiently to allow different
57 code paths to be selected for these cases. Some network 57 code paths to be selected for these cases. Some network
58 drivers, for example, could opt to not fix up alignment 58 drivers, for example, could opt to not fix up alignment
59 problems with received packets if doing so would not help 59 problems with received packets if doing so would not help
60 much. 60 much.
61 61
62 See Documentation/unaligned-memory-access.txt for more 62 See Documentation/unaligned-memory-access.txt for more
63 information on the topic of unaligned memory accesses. 63 information on the topic of unaligned memory accesses.
64 64
65 config HAVE_SYSCALL_WRAPPERS 65 config HAVE_SYSCALL_WRAPPERS
66 bool 66 bool
67 67
68 config KRETPROBES 68 config KRETPROBES
69 def_bool y 69 def_bool y
70 depends on KPROBES && HAVE_KRETPROBES 70 depends on KPROBES && HAVE_KRETPROBES
71 71
72 config HAVE_IOREMAP_PROT 72 config HAVE_IOREMAP_PROT
73 bool 73 bool
74 74
75 config HAVE_KPROBES 75 config HAVE_KPROBES
76 bool 76 bool
77 77
78 config HAVE_KRETPROBES 78 config HAVE_KRETPROBES
79 bool 79 bool
80 80
81 # 81 #
82 # An arch should select this if it provides all these things: 82 # An arch should select this if it provides all these things:
83 # 83 #
84 # task_pt_regs() in asm/processor.h or asm/ptrace.h 84 # task_pt_regs() in asm/processor.h or asm/ptrace.h
85 # arch_has_single_step() if there is hardware single-step support 85 # arch_has_single_step() if there is hardware single-step support
86 # arch_has_block_step() if there is hardware block-step support 86 # arch_has_block_step() if there is hardware block-step support
87 # asm/syscall.h supplying asm-generic/syscall.h interface 87 # asm/syscall.h supplying asm-generic/syscall.h interface
88 # linux/regset.h user_regset interfaces 88 # linux/regset.h user_regset interfaces
89 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h 89 # CORE_DUMP_USE_REGSET #define'd in linux/elf.h
90 # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit} 90 # TIF_SYSCALL_TRACE calls tracehook_report_syscall_{entry,exit}
91 # TIF_NOTIFY_RESUME calls tracehook_notify_resume() 91 # TIF_NOTIFY_RESUME calls tracehook_notify_resume()
92 # signal delivery calls tracehook_signal_handler() 92 # signal delivery calls tracehook_signal_handler()
93 # 93 #
94 config HAVE_ARCH_TRACEHOOK 94 config HAVE_ARCH_TRACEHOOK
95 bool 95 bool
96 96
97 config HAVE_DMA_ATTRS 97 config HAVE_DMA_ATTRS
98 bool 98 bool
99 99
100 config USE_GENERIC_SMP_HELPERS 100 config USE_GENERIC_SMP_HELPERS
101 bool 101 bool
102 102
103 config HAVE_CLK 103 config HAVE_CLK
104 bool 104 bool
105 help 105 help
106 The <linux/clk.h> calls support software clock gating and 106 The <linux/clk.h> calls support software clock gating and
107 thus are a key power management tool on many systems. 107 thus are a key power management tool on many systems.
108
109 config HAVE_DMA_API_DEBUG
110 bool
108 111
1 1
2 config PRINTK_TIME 2 config PRINTK_TIME
3 bool "Show timing information on printks" 3 bool "Show timing information on printks"
4 depends on PRINTK 4 depends on PRINTK
5 help 5 help
6 Selecting this option causes timing information to be 6 Selecting this option causes timing information to be
7 included in printk output. This allows you to measure 7 included in printk output. This allows you to measure
8 the interval between kernel operations, including bootup 8 the interval between kernel operations, including bootup
9 operations. This is useful for identifying long delays 9 operations. This is useful for identifying long delays
10 in kernel startup. 10 in kernel startup.
11 11
12 config ENABLE_WARN_DEPRECATED 12 config ENABLE_WARN_DEPRECATED
13 bool "Enable __deprecated logic" 13 bool "Enable __deprecated logic"
14 default y 14 default y
15 help 15 help
16 Enable the __deprecated logic in the kernel build. 16 Enable the __deprecated logic in the kernel build.
17 Disable this to suppress the "warning: 'foo' is deprecated 17 Disable this to suppress the "warning: 'foo' is deprecated
18 (declared at kernel/power/somefile.c:1234)" messages. 18 (declared at kernel/power/somefile.c:1234)" messages.
19 19
20 config ENABLE_MUST_CHECK 20 config ENABLE_MUST_CHECK
21 bool "Enable __must_check logic" 21 bool "Enable __must_check logic"
22 default y 22 default y
23 help 23 help
24 Enable the __must_check logic in the kernel build. Disable this to 24 Enable the __must_check logic in the kernel build. Disable this to
25 suppress the "warning: ignoring return value of 'foo', declared with 25 suppress the "warning: ignoring return value of 'foo', declared with
26 attribute warn_unused_result" messages. 26 attribute warn_unused_result" messages.
27 27
28 config FRAME_WARN 28 config FRAME_WARN
29 int "Warn for stack frames larger than (needs gcc 4.4)" 29 int "Warn for stack frames larger than (needs gcc 4.4)"
30 range 0 8192 30 range 0 8192
31 default 1024 if !64BIT 31 default 1024 if !64BIT
32 default 2048 if 64BIT 32 default 2048 if 64BIT
33 help 33 help
34 Tell gcc to warn at build time for stack frames larger than this. 34 Tell gcc to warn at build time for stack frames larger than this.
35 Setting this too low will cause a lot of warnings. 35 Setting this too low will cause a lot of warnings.
36 Setting it to 0 disables the warning. 36 Setting it to 0 disables the warning.
37 Requires gcc 4.4 37 Requires gcc 4.4
38 38
39 config MAGIC_SYSRQ 39 config MAGIC_SYSRQ
40 bool "Magic SysRq key" 40 bool "Magic SysRq key"
41 depends on !UML 41 depends on !UML
42 help 42 help
43 If you say Y here, you will have some control over the system even 43 If you say Y here, you will have some control over the system even
44 if the system crashes for example during kernel debugging (e.g., you 44 if the system crashes for example during kernel debugging (e.g., you
45 will be able to flush the buffer cache to disk, reboot the system 45 will be able to flush the buffer cache to disk, reboot the system
46 immediately or dump some status information). This is accomplished 46 immediately or dump some status information). This is accomplished
47 by pressing various keys while holding SysRq (Alt+PrintScreen). It 47 by pressing various keys while holding SysRq (Alt+PrintScreen). It
48 also works on a serial console (on PC hardware at least), if you 48 also works on a serial console (on PC hardware at least), if you
49 send a BREAK and then within 5 seconds a command keypress. The 49 send a BREAK and then within 5 seconds a command keypress. The
50 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y 50 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
51 unless you really know what this hack does. 51 unless you really know what this hack does.
52 52
53 config UNUSED_SYMBOLS 53 config UNUSED_SYMBOLS
54 bool "Enable unused/obsolete exported symbols" 54 bool "Enable unused/obsolete exported symbols"
55 default y if X86 55 default y if X86
56 help 56 help
57 Unused but exported symbols make the kernel needlessly bigger. For 57 Unused but exported symbols make the kernel needlessly bigger. For
58 that reason most of these unused exports will soon be removed. This 58 that reason most of these unused exports will soon be removed. This
59 option is provided temporarily to provide a transition period in case 59 option is provided temporarily to provide a transition period in case
60 some external kernel module needs one of these symbols anyway. If you 60 some external kernel module needs one of these symbols anyway. If you
61 encounter such a case in your module, consider if you are actually 61 encounter such a case in your module, consider if you are actually
62 using the right API. (rationale: since nobody in the kernel is using 62 using the right API. (rationale: since nobody in the kernel is using
63 this in a module, there is a pretty good chance it's actually the 63 this in a module, there is a pretty good chance it's actually the
64 wrong interface to use). If you really need the symbol, please send a 64 wrong interface to use). If you really need the symbol, please send a
65 mail to the linux kernel mailing list mentioning the symbol and why 65 mail to the linux kernel mailing list mentioning the symbol and why
66 you really need it, and what the merge plan to the mainline kernel for 66 you really need it, and what the merge plan to the mainline kernel for
67 your module is. 67 your module is.
68 68
69 config DEBUG_FS 69 config DEBUG_FS
70 bool "Debug Filesystem" 70 bool "Debug Filesystem"
71 depends on SYSFS 71 depends on SYSFS
72 help 72 help
73 debugfs is a virtual file system that kernel developers use to put 73 debugfs is a virtual file system that kernel developers use to put
74 debugging files into. Enable this option to be able to read and 74 debugging files into. Enable this option to be able to read and
75 write to these files. 75 write to these files.
76 76
77 For detailed documentation on the debugfs API, see 77 For detailed documentation on the debugfs API, see
78 Documentation/DocBook/filesystems. 78 Documentation/DocBook/filesystems.
79 79
80 If unsure, say N. 80 If unsure, say N.
81 81
82 config HEADERS_CHECK 82 config HEADERS_CHECK
83 bool "Run 'make headers_check' when building vmlinux" 83 bool "Run 'make headers_check' when building vmlinux"
84 depends on !UML 84 depends on !UML
85 help 85 help
86 This option will extract the user-visible kernel headers whenever 86 This option will extract the user-visible kernel headers whenever
87 building the kernel, and will run basic sanity checks on them to 87 building the kernel, and will run basic sanity checks on them to
88 ensure that exported files do not attempt to include files which 88 ensure that exported files do not attempt to include files which
89 were not exported, etc. 89 were not exported, etc.
90 90
91 If you're making modifications to header files which are 91 If you're making modifications to header files which are
92 relevant for userspace, say 'Y', and check the headers 92 relevant for userspace, say 'Y', and check the headers
93 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in 93 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
94 your build tree), to make sure they're suitable. 94 your build tree), to make sure they're suitable.
95 95
96 config DEBUG_SECTION_MISMATCH 96 config DEBUG_SECTION_MISMATCH
97 bool "Enable full Section mismatch analysis" 97 bool "Enable full Section mismatch analysis"
98 depends on UNDEFINED 98 depends on UNDEFINED
99 # This option is on purpose disabled for now. 99 # This option is on purpose disabled for now.
100 # It will be enabled when we are down to a resonable number 100 # It will be enabled when we are down to a resonable number
101 # of section mismatch warnings (< 10 for an allyesconfig build) 101 # of section mismatch warnings (< 10 for an allyesconfig build)
102 help 102 help
103 The section mismatch analysis checks if there are illegal 103 The section mismatch analysis checks if there are illegal
104 references from one section to another section. 104 references from one section to another section.
105 Linux will during link or during runtime drop some sections 105 Linux will during link or during runtime drop some sections
106 and any use of code/data previously in these sections will 106 and any use of code/data previously in these sections will
107 most likely result in an oops. 107 most likely result in an oops.
108 In the code functions and variables are annotated with 108 In the code functions and variables are annotated with
109 __init, __devinit etc. (see full list in include/linux/init.h) 109 __init, __devinit etc. (see full list in include/linux/init.h)
110 which results in the code/data being placed in specific sections. 110 which results in the code/data being placed in specific sections.
111 The section mismatch analysis is always done after a full 111 The section mismatch analysis is always done after a full
112 kernel build but enabling this option will in addition 112 kernel build but enabling this option will in addition
113 do the following: 113 do the following:
114 - Add the option -fno-inline-functions-called-once to gcc 114 - Add the option -fno-inline-functions-called-once to gcc
115 When inlining a function annotated __init in a non-init 115 When inlining a function annotated __init in a non-init
116 function we would lose the section information and thus 116 function we would lose the section information and thus
117 the analysis would not catch the illegal reference. 117 the analysis would not catch the illegal reference.
118 This option tells gcc to inline less but will also 118 This option tells gcc to inline less but will also
119 result in a larger kernel. 119 result in a larger kernel.
120 - Run the section mismatch analysis for each module/built-in.o 120 - Run the section mismatch analysis for each module/built-in.o
121 When we run the section mismatch analysis on vmlinux.o we 121 When we run the section mismatch analysis on vmlinux.o we
122 lose valueble information about where the mismatch was 122 lose valueble information about where the mismatch was
123 introduced. 123 introduced.
124 Running the analysis for each module/built-in.o file 124 Running the analysis for each module/built-in.o file
125 will tell where the mismatch happens much closer to the 125 will tell where the mismatch happens much closer to the
126 source. The drawback is that we will report the same 126 source. The drawback is that we will report the same
127 mismatch at least twice. 127 mismatch at least twice.
128 - Enable verbose reporting from modpost to help solving 128 - Enable verbose reporting from modpost to help solving
129 the section mismatches reported. 129 the section mismatches reported.
130 130
131 config DEBUG_KERNEL 131 config DEBUG_KERNEL
132 bool "Kernel debugging" 132 bool "Kernel debugging"
133 help 133 help
134 Say Y here if you are developing drivers or trying to debug and 134 Say Y here if you are developing drivers or trying to debug and
135 identify kernel problems. 135 identify kernel problems.
136 136
137 config DEBUG_SHIRQ 137 config DEBUG_SHIRQ
138 bool "Debug shared IRQ handlers" 138 bool "Debug shared IRQ handlers"
139 depends on DEBUG_KERNEL && GENERIC_HARDIRQS 139 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
140 help 140 help
141 Enable this to generate a spurious interrupt as soon as a shared 141 Enable this to generate a spurious interrupt as soon as a shared
142 interrupt handler is registered, and just before one is deregistered. 142 interrupt handler is registered, and just before one is deregistered.
143 Drivers ought to be able to handle interrupts coming in at those 143 Drivers ought to be able to handle interrupts coming in at those
144 points; some don't and need to be caught. 144 points; some don't and need to be caught.
145 145
146 config DETECT_SOFTLOCKUP 146 config DETECT_SOFTLOCKUP
147 bool "Detect Soft Lockups" 147 bool "Detect Soft Lockups"
148 depends on DEBUG_KERNEL && !S390 148 depends on DEBUG_KERNEL && !S390
149 default y 149 default y
150 help 150 help
151 Say Y here to enable the kernel to detect "soft lockups", 151 Say Y here to enable the kernel to detect "soft lockups",
152 which are bugs that cause the kernel to loop in kernel 152 which are bugs that cause the kernel to loop in kernel
153 mode for more than 60 seconds, without giving other tasks a 153 mode for more than 60 seconds, without giving other tasks a
154 chance to run. 154 chance to run.
155 155
156 When a soft-lockup is detected, the kernel will print the 156 When a soft-lockup is detected, the kernel will print the
157 current stack trace (which you should report), but the 157 current stack trace (which you should report), but the
158 system will stay locked up. This feature has negligible 158 system will stay locked up. This feature has negligible
159 overhead. 159 overhead.
160 160
161 (Note that "hard lockups" are separate type of bugs that 161 (Note that "hard lockups" are separate type of bugs that
162 can be detected via the NMI-watchdog, on platforms that 162 can be detected via the NMI-watchdog, on platforms that
163 support it.) 163 support it.)
164 164
165 config BOOTPARAM_SOFTLOCKUP_PANIC 165 config BOOTPARAM_SOFTLOCKUP_PANIC
166 bool "Panic (Reboot) On Soft Lockups" 166 bool "Panic (Reboot) On Soft Lockups"
167 depends on DETECT_SOFTLOCKUP 167 depends on DETECT_SOFTLOCKUP
168 help 168 help
169 Say Y here to enable the kernel to panic on "soft lockups", 169 Say Y here to enable the kernel to panic on "soft lockups",
170 which are bugs that cause the kernel to loop in kernel 170 which are bugs that cause the kernel to loop in kernel
171 mode for more than 60 seconds, without giving other tasks a 171 mode for more than 60 seconds, without giving other tasks a
172 chance to run. 172 chance to run.
173 173
174 The panic can be used in combination with panic_timeout, 174 The panic can be used in combination with panic_timeout,
175 to cause the system to reboot automatically after a 175 to cause the system to reboot automatically after a
176 lockup has been detected. This feature is useful for 176 lockup has been detected. This feature is useful for
177 high-availability systems that have uptime guarantees and 177 high-availability systems that have uptime guarantees and
178 where a lockup must be resolved ASAP. 178 where a lockup must be resolved ASAP.
179 179
180 Say N if unsure. 180 Say N if unsure.
181 181
182 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE 182 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
183 int 183 int
184 depends on DETECT_SOFTLOCKUP 184 depends on DETECT_SOFTLOCKUP
185 range 0 1 185 range 0 1
186 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC 186 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
187 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC 187 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
188 188
189 config SCHED_DEBUG 189 config SCHED_DEBUG
190 bool "Collect scheduler debugging info" 190 bool "Collect scheduler debugging info"
191 depends on DEBUG_KERNEL && PROC_FS 191 depends on DEBUG_KERNEL && PROC_FS
192 default y 192 default y
193 help 193 help
194 If you say Y here, the /proc/sched_debug file will be provided 194 If you say Y here, the /proc/sched_debug file will be provided
195 that can help debug the scheduler. The runtime overhead of this 195 that can help debug the scheduler. The runtime overhead of this
196 option is minimal. 196 option is minimal.
197 197
198 config SCHEDSTATS 198 config SCHEDSTATS
199 bool "Collect scheduler statistics" 199 bool "Collect scheduler statistics"
200 depends on DEBUG_KERNEL && PROC_FS 200 depends on DEBUG_KERNEL && PROC_FS
201 help 201 help
202 If you say Y here, additional code will be inserted into the 202 If you say Y here, additional code will be inserted into the
203 scheduler and related routines to collect statistics about 203 scheduler and related routines to collect statistics about
204 scheduler behavior and provide them in /proc/schedstat. These 204 scheduler behavior and provide them in /proc/schedstat. These
205 stats may be useful for both tuning and debugging the scheduler 205 stats may be useful for both tuning and debugging the scheduler
206 If you aren't debugging the scheduler or trying to tune a specific 206 If you aren't debugging the scheduler or trying to tune a specific
207 application, you can say N to avoid the very slight overhead 207 application, you can say N to avoid the very slight overhead
208 this adds. 208 this adds.
209 209
210 config TIMER_STATS 210 config TIMER_STATS
211 bool "Collect kernel timers statistics" 211 bool "Collect kernel timers statistics"
212 depends on DEBUG_KERNEL && PROC_FS 212 depends on DEBUG_KERNEL && PROC_FS
213 help 213 help
214 If you say Y here, additional code will be inserted into the 214 If you say Y here, additional code will be inserted into the
215 timer routines to collect statistics about kernel timers being 215 timer routines to collect statistics about kernel timers being
216 reprogrammed. The statistics can be read from /proc/timer_stats. 216 reprogrammed. The statistics can be read from /proc/timer_stats.
217 The statistics collection is started by writing 1 to /proc/timer_stats, 217 The statistics collection is started by writing 1 to /proc/timer_stats,
218 writing 0 stops it. This feature is useful to collect information 218 writing 0 stops it. This feature is useful to collect information
219 about timer usage patterns in kernel and userspace. This feature 219 about timer usage patterns in kernel and userspace. This feature
220 is lightweight if enabled in the kernel config but not activated 220 is lightweight if enabled in the kernel config but not activated
221 (it defaults to deactivated on bootup and will only be activated 221 (it defaults to deactivated on bootup and will only be activated
222 if some application like powertop activates it explicitly). 222 if some application like powertop activates it explicitly).
223 223
224 config DEBUG_OBJECTS 224 config DEBUG_OBJECTS
225 bool "Debug object operations" 225 bool "Debug object operations"
226 depends on DEBUG_KERNEL 226 depends on DEBUG_KERNEL
227 help 227 help
228 If you say Y here, additional code will be inserted into the 228 If you say Y here, additional code will be inserted into the
229 kernel to track the life time of various objects and validate 229 kernel to track the life time of various objects and validate
230 the operations on those objects. 230 the operations on those objects.
231 231
232 config DEBUG_OBJECTS_SELFTEST 232 config DEBUG_OBJECTS_SELFTEST
233 bool "Debug objects selftest" 233 bool "Debug objects selftest"
234 depends on DEBUG_OBJECTS 234 depends on DEBUG_OBJECTS
235 help 235 help
236 This enables the selftest of the object debug code. 236 This enables the selftest of the object debug code.
237 237
238 config DEBUG_OBJECTS_FREE 238 config DEBUG_OBJECTS_FREE
239 bool "Debug objects in freed memory" 239 bool "Debug objects in freed memory"
240 depends on DEBUG_OBJECTS 240 depends on DEBUG_OBJECTS
241 help 241 help
242 This enables checks whether a k/v free operation frees an area 242 This enables checks whether a k/v free operation frees an area
243 which contains an object which has not been deactivated 243 which contains an object which has not been deactivated
244 properly. This can make kmalloc/kfree-intensive workloads 244 properly. This can make kmalloc/kfree-intensive workloads
245 much slower. 245 much slower.
246 246
247 config DEBUG_OBJECTS_TIMERS 247 config DEBUG_OBJECTS_TIMERS
248 bool "Debug timer objects" 248 bool "Debug timer objects"
249 depends on DEBUG_OBJECTS 249 depends on DEBUG_OBJECTS
250 help 250 help
251 If you say Y here, additional code will be inserted into the 251 If you say Y here, additional code will be inserted into the
252 timer routines to track the life time of timer objects and 252 timer routines to track the life time of timer objects and
253 validate the timer operations. 253 validate the timer operations.
254 254
255 config DEBUG_OBJECTS_ENABLE_DEFAULT 255 config DEBUG_OBJECTS_ENABLE_DEFAULT
256 int "debug_objects bootup default value (0-1)" 256 int "debug_objects bootup default value (0-1)"
257 range 0 1 257 range 0 1
258 default "1" 258 default "1"
259 depends on DEBUG_OBJECTS 259 depends on DEBUG_OBJECTS
260 help 260 help
261 Debug objects boot parameter default value 261 Debug objects boot parameter default value
262 262
263 config DEBUG_SLAB 263 config DEBUG_SLAB
264 bool "Debug slab memory allocations" 264 bool "Debug slab memory allocations"
265 depends on DEBUG_KERNEL && SLAB 265 depends on DEBUG_KERNEL && SLAB
266 help 266 help
267 Say Y here to have the kernel do limited verification on memory 267 Say Y here to have the kernel do limited verification on memory
268 allocation as well as poisoning memory on free to catch use of freed 268 allocation as well as poisoning memory on free to catch use of freed
269 memory. This can make kmalloc/kfree-intensive workloads much slower. 269 memory. This can make kmalloc/kfree-intensive workloads much slower.
270 270
271 config DEBUG_SLAB_LEAK 271 config DEBUG_SLAB_LEAK
272 bool "Memory leak debugging" 272 bool "Memory leak debugging"
273 depends on DEBUG_SLAB 273 depends on DEBUG_SLAB
274 274
275 config SLUB_DEBUG_ON 275 config SLUB_DEBUG_ON
276 bool "SLUB debugging on by default" 276 bool "SLUB debugging on by default"
277 depends on SLUB && SLUB_DEBUG 277 depends on SLUB && SLUB_DEBUG
278 default n 278 default n
279 help 279 help
280 Boot with debugging on by default. SLUB boots by default with 280 Boot with debugging on by default. SLUB boots by default with
281 the runtime debug capabilities switched off. Enabling this is 281 the runtime debug capabilities switched off. Enabling this is
282 equivalent to specifying the "slub_debug" parameter on boot. 282 equivalent to specifying the "slub_debug" parameter on boot.
283 There is no support for more fine grained debug control like 283 There is no support for more fine grained debug control like
284 possible with slub_debug=xxx. SLUB debugging may be switched 284 possible with slub_debug=xxx. SLUB debugging may be switched
285 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying 285 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
286 "slub_debug=-". 286 "slub_debug=-".
287 287
288 config SLUB_STATS 288 config SLUB_STATS
289 default n 289 default n
290 bool "Enable SLUB performance statistics" 290 bool "Enable SLUB performance statistics"
291 depends on SLUB && SLUB_DEBUG && SYSFS 291 depends on SLUB && SLUB_DEBUG && SYSFS
292 help 292 help
293 SLUB statistics are useful to debug SLUBs allocation behavior in 293 SLUB statistics are useful to debug SLUBs allocation behavior in
294 order find ways to optimize the allocator. This should never be 294 order find ways to optimize the allocator. This should never be
295 enabled for production use since keeping statistics slows down 295 enabled for production use since keeping statistics slows down
296 the allocator by a few percentage points. The slabinfo command 296 the allocator by a few percentage points. The slabinfo command
297 supports the determination of the most active slabs to figure 297 supports the determination of the most active slabs to figure
298 out which slabs are relevant to a particular load. 298 out which slabs are relevant to a particular load.
299 Try running: slabinfo -DA 299 Try running: slabinfo -DA
300 300
301 config DEBUG_PREEMPT 301 config DEBUG_PREEMPT
302 bool "Debug preemptible kernel" 302 bool "Debug preemptible kernel"
303 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64) 303 depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
304 default y 304 default y
305 help 305 help
306 If you say Y here then the kernel will use a debug variant of the 306 If you say Y here then the kernel will use a debug variant of the
307 commonly used smp_processor_id() function and will print warnings 307 commonly used smp_processor_id() function and will print warnings
308 if kernel code uses it in a preemption-unsafe way. Also, the kernel 308 if kernel code uses it in a preemption-unsafe way. Also, the kernel
309 will detect preemption count underflows. 309 will detect preemption count underflows.
310 310
311 config DEBUG_RT_MUTEXES 311 config DEBUG_RT_MUTEXES
312 bool "RT Mutex debugging, deadlock detection" 312 bool "RT Mutex debugging, deadlock detection"
313 depends on DEBUG_KERNEL && RT_MUTEXES 313 depends on DEBUG_KERNEL && RT_MUTEXES
314 help 314 help
315 This allows rt mutex semantics violations and rt mutex related 315 This allows rt mutex semantics violations and rt mutex related
316 deadlocks (lockups) to be detected and reported automatically. 316 deadlocks (lockups) to be detected and reported automatically.
317 317
318 config DEBUG_PI_LIST 318 config DEBUG_PI_LIST
319 bool 319 bool
320 default y 320 default y
321 depends on DEBUG_RT_MUTEXES 321 depends on DEBUG_RT_MUTEXES
322 322
323 config RT_MUTEX_TESTER 323 config RT_MUTEX_TESTER
324 bool "Built-in scriptable tester for rt-mutexes" 324 bool "Built-in scriptable tester for rt-mutexes"
325 depends on DEBUG_KERNEL && RT_MUTEXES 325 depends on DEBUG_KERNEL && RT_MUTEXES
326 help 326 help
327 This option enables a rt-mutex tester. 327 This option enables a rt-mutex tester.
328 328
329 config DEBUG_SPINLOCK 329 config DEBUG_SPINLOCK
330 bool "Spinlock and rw-lock debugging: basic checks" 330 bool "Spinlock and rw-lock debugging: basic checks"
331 depends on DEBUG_KERNEL 331 depends on DEBUG_KERNEL
332 help 332 help
333 Say Y here and build SMP to catch missing spinlock initialization 333 Say Y here and build SMP to catch missing spinlock initialization
334 and certain other kinds of spinlock errors commonly made. This is 334 and certain other kinds of spinlock errors commonly made. This is
335 best used in conjunction with the NMI watchdog so that spinlock 335 best used in conjunction with the NMI watchdog so that spinlock
336 deadlocks are also debuggable. 336 deadlocks are also debuggable.
337 337
338 config DEBUG_MUTEXES 338 config DEBUG_MUTEXES
339 bool "Mutex debugging: basic checks" 339 bool "Mutex debugging: basic checks"
340 depends on DEBUG_KERNEL 340 depends on DEBUG_KERNEL
341 help 341 help
342 This feature allows mutex semantics violations to be detected and 342 This feature allows mutex semantics violations to be detected and
343 reported. 343 reported.
344 344
345 config DEBUG_LOCK_ALLOC 345 config DEBUG_LOCK_ALLOC
346 bool "Lock debugging: detect incorrect freeing of live locks" 346 bool "Lock debugging: detect incorrect freeing of live locks"
347 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 347 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
348 select DEBUG_SPINLOCK 348 select DEBUG_SPINLOCK
349 select DEBUG_MUTEXES 349 select DEBUG_MUTEXES
350 select LOCKDEP 350 select LOCKDEP
351 help 351 help
352 This feature will check whether any held lock (spinlock, rwlock, 352 This feature will check whether any held lock (spinlock, rwlock,
353 mutex or rwsem) is incorrectly freed by the kernel, via any of the 353 mutex or rwsem) is incorrectly freed by the kernel, via any of the
354 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 354 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
355 vfree(), etc.), whether a live lock is incorrectly reinitialized via 355 vfree(), etc.), whether a live lock is incorrectly reinitialized via
356 spin_lock_init()/mutex_init()/etc., or whether there is any lock 356 spin_lock_init()/mutex_init()/etc., or whether there is any lock
357 held during task exit. 357 held during task exit.
358 358
359 config PROVE_LOCKING 359 config PROVE_LOCKING
360 bool "Lock debugging: prove locking correctness" 360 bool "Lock debugging: prove locking correctness"
361 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 361 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
362 select LOCKDEP 362 select LOCKDEP
363 select DEBUG_SPINLOCK 363 select DEBUG_SPINLOCK
364 select DEBUG_MUTEXES 364 select DEBUG_MUTEXES
365 select DEBUG_LOCK_ALLOC 365 select DEBUG_LOCK_ALLOC
366 default n 366 default n
367 help 367 help
368 This feature enables the kernel to prove that all locking 368 This feature enables the kernel to prove that all locking
369 that occurs in the kernel runtime is mathematically 369 that occurs in the kernel runtime is mathematically
370 correct: that under no circumstance could an arbitrary (and 370 correct: that under no circumstance could an arbitrary (and
371 not yet triggered) combination of observed locking 371 not yet triggered) combination of observed locking
372 sequences (on an arbitrary number of CPUs, running an 372 sequences (on an arbitrary number of CPUs, running an
373 arbitrary number of tasks and interrupt contexts) cause a 373 arbitrary number of tasks and interrupt contexts) cause a
374 deadlock. 374 deadlock.
375 375
376 In short, this feature enables the kernel to report locking 376 In short, this feature enables the kernel to report locking
377 related deadlocks before they actually occur. 377 related deadlocks before they actually occur.
378 378
379 The proof does not depend on how hard and complex a 379 The proof does not depend on how hard and complex a
380 deadlock scenario would be to trigger: how many 380 deadlock scenario would be to trigger: how many
381 participant CPUs, tasks and irq-contexts would be needed 381 participant CPUs, tasks and irq-contexts would be needed
382 for it to trigger. The proof also does not depend on 382 for it to trigger. The proof also does not depend on
383 timing: if a race and a resulting deadlock is possible 383 timing: if a race and a resulting deadlock is possible
384 theoretically (no matter how unlikely the race scenario 384 theoretically (no matter how unlikely the race scenario
385 is), it will be proven so and will immediately be 385 is), it will be proven so and will immediately be
386 reported by the kernel (once the event is observed that 386 reported by the kernel (once the event is observed that
387 makes the deadlock theoretically possible). 387 makes the deadlock theoretically possible).
388 388
389 If a deadlock is impossible (i.e. the locking rules, as 389 If a deadlock is impossible (i.e. the locking rules, as
390 observed by the kernel, are mathematically correct), the 390 observed by the kernel, are mathematically correct), the
391 kernel reports nothing. 391 kernel reports nothing.
392 392
393 NOTE: this feature can also be enabled for rwlocks, mutexes 393 NOTE: this feature can also be enabled for rwlocks, mutexes
394 and rwsems - in which case all dependencies between these 394 and rwsems - in which case all dependencies between these
395 different locking variants are observed and mapped too, and 395 different locking variants are observed and mapped too, and
396 the proof of observed correctness is also maintained for an 396 the proof of observed correctness is also maintained for an
397 arbitrary combination of these separate locking variants. 397 arbitrary combination of these separate locking variants.
398 398
399 For more details, see Documentation/lockdep-design.txt. 399 For more details, see Documentation/lockdep-design.txt.
400 400
401 config LOCKDEP 401 config LOCKDEP
402 bool 402 bool
403 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 403 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
404 select STACKTRACE 404 select STACKTRACE
405 select FRAME_POINTER if !X86 && !MIPS && !PPC 405 select FRAME_POINTER if !X86 && !MIPS && !PPC
406 select KALLSYMS 406 select KALLSYMS
407 select KALLSYMS_ALL 407 select KALLSYMS_ALL
408 408
409 config LOCK_STAT 409 config LOCK_STAT
410 bool "Lock usage statistics" 410 bool "Lock usage statistics"
411 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 411 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
412 select LOCKDEP 412 select LOCKDEP
413 select DEBUG_SPINLOCK 413 select DEBUG_SPINLOCK
414 select DEBUG_MUTEXES 414 select DEBUG_MUTEXES
415 select DEBUG_LOCK_ALLOC 415 select DEBUG_LOCK_ALLOC
416 default n 416 default n
417 help 417 help
418 This feature enables tracking lock contention points 418 This feature enables tracking lock contention points
419 419
420 For more details, see Documentation/lockstat.txt 420 For more details, see Documentation/lockstat.txt
421 421
422 config DEBUG_LOCKDEP 422 config DEBUG_LOCKDEP
423 bool "Lock dependency engine debugging" 423 bool "Lock dependency engine debugging"
424 depends on DEBUG_KERNEL && LOCKDEP 424 depends on DEBUG_KERNEL && LOCKDEP
425 help 425 help
426 If you say Y here, the lock dependency engine will do 426 If you say Y here, the lock dependency engine will do
427 additional runtime checks to debug itself, at the price 427 additional runtime checks to debug itself, at the price
428 of more runtime overhead. 428 of more runtime overhead.
429 429
430 config TRACE_IRQFLAGS 430 config TRACE_IRQFLAGS
431 depends on DEBUG_KERNEL 431 depends on DEBUG_KERNEL
432 bool 432 bool
433 default y 433 default y
434 depends on TRACE_IRQFLAGS_SUPPORT 434 depends on TRACE_IRQFLAGS_SUPPORT
435 depends on PROVE_LOCKING 435 depends on PROVE_LOCKING
436 436
437 config DEBUG_SPINLOCK_SLEEP 437 config DEBUG_SPINLOCK_SLEEP
438 bool "Spinlock debugging: sleep-inside-spinlock checking" 438 bool "Spinlock debugging: sleep-inside-spinlock checking"
439 depends on DEBUG_KERNEL 439 depends on DEBUG_KERNEL
440 help 440 help
441 If you say Y here, various routines which may sleep will become very 441 If you say Y here, various routines which may sleep will become very
442 noisy if they are called with a spinlock held. 442 noisy if they are called with a spinlock held.
443 443
444 config DEBUG_LOCKING_API_SELFTESTS 444 config DEBUG_LOCKING_API_SELFTESTS
445 bool "Locking API boot-time self-tests" 445 bool "Locking API boot-time self-tests"
446 depends on DEBUG_KERNEL 446 depends on DEBUG_KERNEL
447 help 447 help
448 Say Y here if you want the kernel to run a short self-test during 448 Say Y here if you want the kernel to run a short self-test during
449 bootup. The self-test checks whether common types of locking bugs 449 bootup. The self-test checks whether common types of locking bugs
450 are detected by debugging mechanisms or not. (if you disable 450 are detected by debugging mechanisms or not. (if you disable
451 lock debugging then those bugs wont be detected of course.) 451 lock debugging then those bugs wont be detected of course.)
452 The following locking APIs are covered: spinlocks, rwlocks, 452 The following locking APIs are covered: spinlocks, rwlocks,
453 mutexes and rwsems. 453 mutexes and rwsems.
454 454
455 config STACKTRACE 455 config STACKTRACE
456 bool 456 bool
457 depends on STACKTRACE_SUPPORT 457 depends on STACKTRACE_SUPPORT
458 458
459 config DEBUG_KOBJECT 459 config DEBUG_KOBJECT
460 bool "kobject debugging" 460 bool "kobject debugging"
461 depends on DEBUG_KERNEL 461 depends on DEBUG_KERNEL
462 help 462 help
463 If you say Y here, some extra kobject debugging messages will be sent 463 If you say Y here, some extra kobject debugging messages will be sent
464 to the syslog. 464 to the syslog.
465 465
466 config DEBUG_HIGHMEM 466 config DEBUG_HIGHMEM
467 bool "Highmem debugging" 467 bool "Highmem debugging"
468 depends on DEBUG_KERNEL && HIGHMEM 468 depends on DEBUG_KERNEL && HIGHMEM
469 help 469 help
470 This options enables addition error checking for high memory systems. 470 This options enables addition error checking for high memory systems.
471 Disable for production systems. 471 Disable for production systems.
472 472
473 config DEBUG_BUGVERBOSE 473 config DEBUG_BUGVERBOSE
474 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED 474 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
475 depends on BUG 475 depends on BUG
476 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \ 476 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
477 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 477 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
478 default !EMBEDDED 478 default !EMBEDDED
479 help 479 help
480 Say Y here to make BUG() panics output the file name and line number 480 Say Y here to make BUG() panics output the file name and line number
481 of the BUG call as well as the EIP and oops trace. This aids 481 of the BUG call as well as the EIP and oops trace. This aids
482 debugging but costs about 70-100K of memory. 482 debugging but costs about 70-100K of memory.
483 483
484 config DEBUG_INFO 484 config DEBUG_INFO
485 bool "Compile the kernel with debug info" 485 bool "Compile the kernel with debug info"
486 depends on DEBUG_KERNEL 486 depends on DEBUG_KERNEL
487 help 487 help
488 If you say Y here the resulting kernel image will include 488 If you say Y here the resulting kernel image will include
489 debugging info resulting in a larger kernel image. 489 debugging info resulting in a larger kernel image.
490 This adds debug symbols to the kernel and modules (gcc -g), and 490 This adds debug symbols to the kernel and modules (gcc -g), and
491 is needed if you intend to use kernel crashdump or binary object 491 is needed if you intend to use kernel crashdump or binary object
492 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 492 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
493 Say Y here only if you plan to debug the kernel. 493 Say Y here only if you plan to debug the kernel.
494 494
495 If unsure, say N. 495 If unsure, say N.
496 496
497 config DEBUG_VM 497 config DEBUG_VM
498 bool "Debug VM" 498 bool "Debug VM"
499 depends on DEBUG_KERNEL 499 depends on DEBUG_KERNEL
500 help 500 help
501 Enable this to turn on extended checks in the virtual-memory system 501 Enable this to turn on extended checks in the virtual-memory system
502 that may impact performance. 502 that may impact performance.
503 503
504 If unsure, say N. 504 If unsure, say N.
505 505
506 config DEBUG_VIRTUAL 506 config DEBUG_VIRTUAL
507 bool "Debug VM translations" 507 bool "Debug VM translations"
508 depends on DEBUG_KERNEL && X86 508 depends on DEBUG_KERNEL && X86
509 help 509 help
510 Enable some costly sanity checks in virtual to page code. This can 510 Enable some costly sanity checks in virtual to page code. This can
511 catch mistakes with virt_to_page() and friends. 511 catch mistakes with virt_to_page() and friends.
512 512
513 If unsure, say N. 513 If unsure, say N.
514 514
515 config DEBUG_NOMMU_REGIONS 515 config DEBUG_NOMMU_REGIONS
516 bool "Debug the global anon/private NOMMU mapping region tree" 516 bool "Debug the global anon/private NOMMU mapping region tree"
517 depends on DEBUG_KERNEL && !MMU 517 depends on DEBUG_KERNEL && !MMU
518 help 518 help
519 This option causes the global tree of anonymous and private mapping 519 This option causes the global tree of anonymous and private mapping
520 regions to be regularly checked for invalid topology. 520 regions to be regularly checked for invalid topology.
521 521
522 config DEBUG_WRITECOUNT 522 config DEBUG_WRITECOUNT
523 bool "Debug filesystem writers count" 523 bool "Debug filesystem writers count"
524 depends on DEBUG_KERNEL 524 depends on DEBUG_KERNEL
525 help 525 help
526 Enable this to catch wrong use of the writers count in struct 526 Enable this to catch wrong use of the writers count in struct
527 vfsmount. This will increase the size of each file struct by 527 vfsmount. This will increase the size of each file struct by
528 32 bits. 528 32 bits.
529 529
530 If unsure, say N. 530 If unsure, say N.
531 531
532 config DEBUG_MEMORY_INIT 532 config DEBUG_MEMORY_INIT
533 bool "Debug memory initialisation" if EMBEDDED 533 bool "Debug memory initialisation" if EMBEDDED
534 default !EMBEDDED 534 default !EMBEDDED
535 help 535 help
536 Enable this for additional checks during memory initialisation. 536 Enable this for additional checks during memory initialisation.
537 The sanity checks verify aspects of the VM such as the memory model 537 The sanity checks verify aspects of the VM such as the memory model
538 and other information provided by the architecture. Verbose 538 and other information provided by the architecture. Verbose
539 information will be printed at KERN_DEBUG loglevel depending 539 information will be printed at KERN_DEBUG loglevel depending
540 on the mminit_loglevel= command-line option. 540 on the mminit_loglevel= command-line option.
541 541
542 If unsure, say Y 542 If unsure, say Y
543 543
544 config DEBUG_LIST 544 config DEBUG_LIST
545 bool "Debug linked list manipulation" 545 bool "Debug linked list manipulation"
546 depends on DEBUG_KERNEL 546 depends on DEBUG_KERNEL
547 help 547 help
548 Enable this to turn on extended checks in the linked-list 548 Enable this to turn on extended checks in the linked-list
549 walking routines. 549 walking routines.
550 550
551 If unsure, say N. 551 If unsure, say N.
552 552
553 config DEBUG_SG 553 config DEBUG_SG
554 bool "Debug SG table operations" 554 bool "Debug SG table operations"
555 depends on DEBUG_KERNEL 555 depends on DEBUG_KERNEL
556 help 556 help
557 Enable this to turn on checks on scatter-gather tables. This can 557 Enable this to turn on checks on scatter-gather tables. This can
558 help find problems with drivers that do not properly initialize 558 help find problems with drivers that do not properly initialize
559 their sg tables. 559 their sg tables.
560 560
561 If unsure, say N. 561 If unsure, say N.
562 562
563 config DEBUG_NOTIFIERS 563 config DEBUG_NOTIFIERS
564 bool "Debug notifier call chains" 564 bool "Debug notifier call chains"
565 depends on DEBUG_KERNEL 565 depends on DEBUG_KERNEL
566 help 566 help
567 Enable this to turn on sanity checking for notifier call chains. 567 Enable this to turn on sanity checking for notifier call chains.
568 This is most useful for kernel developers to make sure that 568 This is most useful for kernel developers to make sure that
569 modules properly unregister themselves from notifier chains. 569 modules properly unregister themselves from notifier chains.
570 This is a relatively cheap check but if you care about maximum 570 This is a relatively cheap check but if you care about maximum
571 performance, say N. 571 performance, say N.
572 572
573 # 573 #
574 # Select this config option from the architecture Kconfig, if it 574 # Select this config option from the architecture Kconfig, if it
575 # it is preferred to always offer frame pointers as a config 575 # it is preferred to always offer frame pointers as a config
576 # option on the architecture (regardless of KERNEL_DEBUG): 576 # option on the architecture (regardless of KERNEL_DEBUG):
577 # 577 #
578 config ARCH_WANT_FRAME_POINTERS 578 config ARCH_WANT_FRAME_POINTERS
579 bool 579 bool
580 help 580 help
581 581
582 config FRAME_POINTER 582 config FRAME_POINTER
583 bool "Compile the kernel with frame pointers" 583 bool "Compile the kernel with frame pointers"
584 depends on DEBUG_KERNEL && \ 584 depends on DEBUG_KERNEL && \
585 (CRIS || M68K || M68KNOMMU || FRV || UML || S390 || \ 585 (CRIS || M68K || M68KNOMMU || FRV || UML || S390 || \
586 AVR32 || SUPERH || BLACKFIN || MN10300) || \ 586 AVR32 || SUPERH || BLACKFIN || MN10300) || \
587 ARCH_WANT_FRAME_POINTERS 587 ARCH_WANT_FRAME_POINTERS
588 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 588 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
589 help 589 help
590 If you say Y here the resulting kernel image will be slightly 590 If you say Y here the resulting kernel image will be slightly
591 larger and slower, but it gives very useful debugging information 591 larger and slower, but it gives very useful debugging information
592 in case of kernel bugs. (precise oopses/stacktraces/warnings) 592 in case of kernel bugs. (precise oopses/stacktraces/warnings)
593 593
594 config BOOT_PRINTK_DELAY 594 config BOOT_PRINTK_DELAY
595 bool "Delay each boot printk message by N milliseconds" 595 bool "Delay each boot printk message by N milliseconds"
596 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY 596 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
597 help 597 help
598 This build option allows you to read kernel boot messages 598 This build option allows you to read kernel boot messages
599 by inserting a short delay after each one. The delay is 599 by inserting a short delay after each one. The delay is
600 specified in milliseconds on the kernel command line, 600 specified in milliseconds on the kernel command line,
601 using "boot_delay=N". 601 using "boot_delay=N".
602 602
603 It is likely that you would also need to use "lpj=M" to preset 603 It is likely that you would also need to use "lpj=M" to preset
604 the "loops per jiffie" value. 604 the "loops per jiffie" value.
605 See a previous boot log for the "lpj" value to use for your 605 See a previous boot log for the "lpj" value to use for your
606 system, and then set "lpj=M" before setting "boot_delay=N". 606 system, and then set "lpj=M" before setting "boot_delay=N".
607 NOTE: Using this option may adversely affect SMP systems. 607 NOTE: Using this option may adversely affect SMP systems.
608 I.e., processors other than the first one may not boot up. 608 I.e., processors other than the first one may not boot up.
609 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect 609 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
610 what it believes to be lockup conditions. 610 what it believes to be lockup conditions.
611 611
612 config RCU_TORTURE_TEST 612 config RCU_TORTURE_TEST
613 tristate "torture tests for RCU" 613 tristate "torture tests for RCU"
614 depends on DEBUG_KERNEL 614 depends on DEBUG_KERNEL
615 default n 615 default n
616 help 616 help
617 This option provides a kernel module that runs torture tests 617 This option provides a kernel module that runs torture tests
618 on the RCU infrastructure. The kernel module may be built 618 on the RCU infrastructure. The kernel module may be built
619 after the fact on the running kernel to be tested, if desired. 619 after the fact on the running kernel to be tested, if desired.
620 620
621 Say Y here if you want RCU torture tests to be built into 621 Say Y here if you want RCU torture tests to be built into
622 the kernel. 622 the kernel.
623 Say M if you want the RCU torture tests to build as a module. 623 Say M if you want the RCU torture tests to build as a module.
624 Say N if you are unsure. 624 Say N if you are unsure.
625 625
626 config RCU_TORTURE_TEST_RUNNABLE 626 config RCU_TORTURE_TEST_RUNNABLE
627 bool "torture tests for RCU runnable by default" 627 bool "torture tests for RCU runnable by default"
628 depends on RCU_TORTURE_TEST = y 628 depends on RCU_TORTURE_TEST = y
629 default n 629 default n
630 help 630 help
631 This option provides a way to build the RCU torture tests 631 This option provides a way to build the RCU torture tests
632 directly into the kernel without them starting up at boot 632 directly into the kernel without them starting up at boot
633 time. You can use /proc/sys/kernel/rcutorture_runnable 633 time. You can use /proc/sys/kernel/rcutorture_runnable
634 to manually override this setting. This /proc file is 634 to manually override this setting. This /proc file is
635 available only when the RCU torture tests have been built 635 available only when the RCU torture tests have been built
636 into the kernel. 636 into the kernel.
637 637
638 Say Y here if you want the RCU torture tests to start during 638 Say Y here if you want the RCU torture tests to start during
639 boot (you probably don't). 639 boot (you probably don't).
640 Say N here if you want the RCU torture tests to start only 640 Say N here if you want the RCU torture tests to start only
641 after being manually enabled via /proc. 641 after being manually enabled via /proc.
642 642
643 config RCU_CPU_STALL_DETECTOR 643 config RCU_CPU_STALL_DETECTOR
644 bool "Check for stalled CPUs delaying RCU grace periods" 644 bool "Check for stalled CPUs delaying RCU grace periods"
645 depends on CLASSIC_RCU || TREE_RCU 645 depends on CLASSIC_RCU || TREE_RCU
646 default n 646 default n
647 help 647 help
648 This option causes RCU to printk information on which 648 This option causes RCU to printk information on which
649 CPUs are delaying the current grace period, but only when 649 CPUs are delaying the current grace period, but only when
650 the grace period extends for excessive time periods. 650 the grace period extends for excessive time periods.
651 651
652 Say Y if you want RCU to perform such checks. 652 Say Y if you want RCU to perform such checks.
653 653
654 Say N if you are unsure. 654 Say N if you are unsure.
655 655
656 config KPROBES_SANITY_TEST 656 config KPROBES_SANITY_TEST
657 bool "Kprobes sanity tests" 657 bool "Kprobes sanity tests"
658 depends on DEBUG_KERNEL 658 depends on DEBUG_KERNEL
659 depends on KPROBES 659 depends on KPROBES
660 default n 660 default n
661 help 661 help
662 This option provides for testing basic kprobes functionality on 662 This option provides for testing basic kprobes functionality on
663 boot. A sample kprobe, jprobe and kretprobe are inserted and 663 boot. A sample kprobe, jprobe and kretprobe are inserted and
664 verified for functionality. 664 verified for functionality.
665 665
666 Say N if you are unsure. 666 Say N if you are unsure.
667 667
668 config BACKTRACE_SELF_TEST 668 config BACKTRACE_SELF_TEST
669 tristate "Self test for the backtrace code" 669 tristate "Self test for the backtrace code"
670 depends on DEBUG_KERNEL 670 depends on DEBUG_KERNEL
671 default n 671 default n
672 help 672 help
673 This option provides a kernel module that can be used to test 673 This option provides a kernel module that can be used to test
674 the kernel stack backtrace code. This option is not useful 674 the kernel stack backtrace code. This option is not useful
675 for distributions or general kernels, but only for kernel 675 for distributions or general kernels, but only for kernel
676 developers working on architecture code. 676 developers working on architecture code.
677 677
678 Note that if you want to also test saved backtraces, you will 678 Note that if you want to also test saved backtraces, you will
679 have to enable STACKTRACE as well. 679 have to enable STACKTRACE as well.
680 680
681 Say N if you are unsure. 681 Say N if you are unsure.
682 682
683 config DEBUG_BLOCK_EXT_DEVT 683 config DEBUG_BLOCK_EXT_DEVT
684 bool "Force extended block device numbers and spread them" 684 bool "Force extended block device numbers and spread them"
685 depends on DEBUG_KERNEL 685 depends on DEBUG_KERNEL
686 depends on BLOCK 686 depends on BLOCK
687 default n 687 default n
688 help 688 help
689 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON 689 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
690 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT 690 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
691 YOU ARE DOING. Distros, please enable this and fix whatever 691 YOU ARE DOING. Distros, please enable this and fix whatever
692 is broken. 692 is broken.
693 693
694 Conventionally, block device numbers are allocated from 694 Conventionally, block device numbers are allocated from
695 predetermined contiguous area. However, extended block area 695 predetermined contiguous area. However, extended block area
696 may introduce non-contiguous block device numbers. This 696 may introduce non-contiguous block device numbers. This
697 option forces most block device numbers to be allocated from 697 option forces most block device numbers to be allocated from
698 the extended space and spreads them to discover kernel or 698 the extended space and spreads them to discover kernel or
699 userland code paths which assume predetermined contiguous 699 userland code paths which assume predetermined contiguous
700 device number allocation. 700 device number allocation.
701 701
702 Note that turning on this debug option shuffles all the 702 Note that turning on this debug option shuffles all the
703 device numbers for all IDE and SCSI devices including libata 703 device numbers for all IDE and SCSI devices including libata
704 ones, so root partition specified using device number 704 ones, so root partition specified using device number
705 directly (via rdev or root=MAJ:MIN) won't work anymore. 705 directly (via rdev or root=MAJ:MIN) won't work anymore.
706 Textual device names (root=/dev/sdXn) will continue to work. 706 Textual device names (root=/dev/sdXn) will continue to work.
707 707
708 Say N if you are unsure. 708 Say N if you are unsure.
709 709
710 config LKDTM 710 config LKDTM
711 tristate "Linux Kernel Dump Test Tool Module" 711 tristate "Linux Kernel Dump Test Tool Module"
712 depends on DEBUG_KERNEL 712 depends on DEBUG_KERNEL
713 depends on KPROBES 713 depends on KPROBES
714 depends on BLOCK 714 depends on BLOCK
715 default n 715 default n
716 help 716 help
717 This module enables testing of the different dumping mechanisms by 717 This module enables testing of the different dumping mechanisms by
718 inducing system failures at predefined crash points. 718 inducing system failures at predefined crash points.
719 If you don't need it: say N 719 If you don't need it: say N
720 Choose M here to compile this code as a module. The module will be 720 Choose M here to compile this code as a module. The module will be
721 called lkdtm. 721 called lkdtm.
722 722
723 Documentation on how to use the module can be found in 723 Documentation on how to use the module can be found in
724 drivers/misc/lkdtm.c 724 drivers/misc/lkdtm.c
725 725
726 config FAULT_INJECTION 726 config FAULT_INJECTION
727 bool "Fault-injection framework" 727 bool "Fault-injection framework"
728 depends on DEBUG_KERNEL 728 depends on DEBUG_KERNEL
729 help 729 help
730 Provide fault-injection framework. 730 Provide fault-injection framework.
731 For more details, see Documentation/fault-injection/. 731 For more details, see Documentation/fault-injection/.
732 732
733 config FAILSLAB 733 config FAILSLAB
734 bool "Fault-injection capability for kmalloc" 734 bool "Fault-injection capability for kmalloc"
735 depends on FAULT_INJECTION 735 depends on FAULT_INJECTION
736 depends on SLAB || SLUB 736 depends on SLAB || SLUB
737 help 737 help
738 Provide fault-injection capability for kmalloc. 738 Provide fault-injection capability for kmalloc.
739 739
740 config FAIL_PAGE_ALLOC 740 config FAIL_PAGE_ALLOC
741 bool "Fault-injection capabilitiy for alloc_pages()" 741 bool "Fault-injection capabilitiy for alloc_pages()"
742 depends on FAULT_INJECTION 742 depends on FAULT_INJECTION
743 help 743 help
744 Provide fault-injection capability for alloc_pages(). 744 Provide fault-injection capability for alloc_pages().
745 745
746 config FAIL_MAKE_REQUEST 746 config FAIL_MAKE_REQUEST
747 bool "Fault-injection capability for disk IO" 747 bool "Fault-injection capability for disk IO"
748 depends on FAULT_INJECTION && BLOCK 748 depends on FAULT_INJECTION && BLOCK
749 help 749 help
750 Provide fault-injection capability for disk IO. 750 Provide fault-injection capability for disk IO.
751 751
752 config FAIL_IO_TIMEOUT 752 config FAIL_IO_TIMEOUT
753 bool "Faul-injection capability for faking disk interrupts" 753 bool "Faul-injection capability for faking disk interrupts"
754 depends on FAULT_INJECTION && BLOCK 754 depends on FAULT_INJECTION && BLOCK
755 help 755 help
756 Provide fault-injection capability on end IO handling. This 756 Provide fault-injection capability on end IO handling. This
757 will make the block layer "forget" an interrupt as configured, 757 will make the block layer "forget" an interrupt as configured,
758 thus exercising the error handling. 758 thus exercising the error handling.
759 759
760 Only works with drivers that use the generic timeout handling, 760 Only works with drivers that use the generic timeout handling,
761 for others it wont do anything. 761 for others it wont do anything.
762 762
763 config FAULT_INJECTION_DEBUG_FS 763 config FAULT_INJECTION_DEBUG_FS
764 bool "Debugfs entries for fault-injection capabilities" 764 bool "Debugfs entries for fault-injection capabilities"
765 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 765 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
766 help 766 help
767 Enable configuration of fault-injection capabilities via debugfs. 767 Enable configuration of fault-injection capabilities via debugfs.
768 768
769 config FAULT_INJECTION_STACKTRACE_FILTER 769 config FAULT_INJECTION_STACKTRACE_FILTER
770 bool "stacktrace filter for fault-injection capabilities" 770 bool "stacktrace filter for fault-injection capabilities"
771 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 771 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
772 depends on !X86_64 772 depends on !X86_64
773 select STACKTRACE 773 select STACKTRACE
774 select FRAME_POINTER if !PPC 774 select FRAME_POINTER if !PPC
775 help 775 help
776 Provide stacktrace filter for fault-injection capabilities 776 Provide stacktrace filter for fault-injection capabilities
777 777
778 config LATENCYTOP 778 config LATENCYTOP
779 bool "Latency measuring infrastructure" 779 bool "Latency measuring infrastructure"
780 select FRAME_POINTER if !MIPS && !PPC 780 select FRAME_POINTER if !MIPS && !PPC
781 select KALLSYMS 781 select KALLSYMS
782 select KALLSYMS_ALL 782 select KALLSYMS_ALL
783 select STACKTRACE 783 select STACKTRACE
784 select SCHEDSTATS 784 select SCHEDSTATS
785 select SCHED_DEBUG 785 select SCHED_DEBUG
786 depends on HAVE_LATENCYTOP_SUPPORT 786 depends on HAVE_LATENCYTOP_SUPPORT
787 help 787 help
788 Enable this option if you want to use the LatencyTOP tool 788 Enable this option if you want to use the LatencyTOP tool
789 to find out which userspace is blocking on what kernel operations. 789 to find out which userspace is blocking on what kernel operations.
790 790
791 config SYSCTL_SYSCALL_CHECK 791 config SYSCTL_SYSCALL_CHECK
792 bool "Sysctl checks" 792 bool "Sysctl checks"
793 depends on SYSCTL_SYSCALL 793 depends on SYSCTL_SYSCALL
794 ---help--- 794 ---help---
795 sys_sysctl uses binary paths that have been found challenging 795 sys_sysctl uses binary paths that have been found challenging
796 to properly maintain and use. This enables checks that help 796 to properly maintain and use. This enables checks that help
797 you to keep things correct. 797 you to keep things correct.
798 798
799 source kernel/trace/Kconfig 799 source kernel/trace/Kconfig
800 800
801 config PROVIDE_OHCI1394_DMA_INIT 801 config PROVIDE_OHCI1394_DMA_INIT
802 bool "Remote debugging over FireWire early on boot" 802 bool "Remote debugging over FireWire early on boot"
803 depends on PCI && X86 803 depends on PCI && X86
804 help 804 help
805 If you want to debug problems which hang or crash the kernel early 805 If you want to debug problems which hang or crash the kernel early
806 on boot and the crashing machine has a FireWire port, you can use 806 on boot and the crashing machine has a FireWire port, you can use
807 this feature to remotely access the memory of the crashed machine 807 this feature to remotely access the memory of the crashed machine
808 over FireWire. This employs remote DMA as part of the OHCI1394 808 over FireWire. This employs remote DMA as part of the OHCI1394
809 specification which is now the standard for FireWire controllers. 809 specification which is now the standard for FireWire controllers.
810 810
811 With remote DMA, you can monitor the printk buffer remotely using 811 With remote DMA, you can monitor the printk buffer remotely using
812 firescope and access all memory below 4GB using fireproxy from gdb. 812 firescope and access all memory below 4GB using fireproxy from gdb.
813 Even controlling a kernel debugger is possible using remote DMA. 813 Even controlling a kernel debugger is possible using remote DMA.
814 814
815 Usage: 815 Usage:
816 816
817 If ohci1394_dma=early is used as boot parameter, it will initialize 817 If ohci1394_dma=early is used as boot parameter, it will initialize
818 all OHCI1394 controllers which are found in the PCI config space. 818 all OHCI1394 controllers which are found in the PCI config space.
819 819
820 As all changes to the FireWire bus such as enabling and disabling 820 As all changes to the FireWire bus such as enabling and disabling
821 devices cause a bus reset and thereby disable remote DMA for all 821 devices cause a bus reset and thereby disable remote DMA for all
822 devices, be sure to have the cable plugged and FireWire enabled on 822 devices, be sure to have the cable plugged and FireWire enabled on
823 the debugging host before booting the debug target for debugging. 823 the debugging host before booting the debug target for debugging.
824 824
825 This code (~1k) is freed after boot. By then, the firewire stack 825 This code (~1k) is freed after boot. By then, the firewire stack
826 in charge of the OHCI-1394 controllers should be used instead. 826 in charge of the OHCI-1394 controllers should be used instead.
827 827
828 See Documentation/debugging-via-ohci1394.txt for more information. 828 See Documentation/debugging-via-ohci1394.txt for more information.
829 829
830 config FIREWIRE_OHCI_REMOTE_DMA 830 config FIREWIRE_OHCI_REMOTE_DMA
831 bool "Remote debugging over FireWire with firewire-ohci" 831 bool "Remote debugging over FireWire with firewire-ohci"
832 depends on FIREWIRE_OHCI 832 depends on FIREWIRE_OHCI
833 help 833 help
834 This option lets you use the FireWire bus for remote debugging 834 This option lets you use the FireWire bus for remote debugging
835 with help of the firewire-ohci driver. It enables unfiltered 835 with help of the firewire-ohci driver. It enables unfiltered
836 remote DMA in firewire-ohci. 836 remote DMA in firewire-ohci.
837 See Documentation/debugging-via-ohci1394.txt for more information. 837 See Documentation/debugging-via-ohci1394.txt for more information.
838 838
839 If unsure, say N. 839 If unsure, say N.
840 840
841 config BUILD_DOCSRC 841 config BUILD_DOCSRC
842 bool "Build targets in Documentation/ tree" 842 bool "Build targets in Documentation/ tree"
843 depends on HEADERS_CHECK 843 depends on HEADERS_CHECK
844 help 844 help
845 This option attempts to build objects from the source files in the 845 This option attempts to build objects from the source files in the
846 kernel Documentation/ tree. 846 kernel Documentation/ tree.
847 847
848 Say N if you are unsure. 848 Say N if you are unsure.
849 849
850 config DYNAMIC_PRINTK_DEBUG 850 config DYNAMIC_PRINTK_DEBUG
851 bool "Enable dynamic printk() call support" 851 bool "Enable dynamic printk() call support"
852 default n 852 default n
853 depends on PRINTK 853 depends on PRINTK
854 select PRINTK_DEBUG 854 select PRINTK_DEBUG
855 help 855 help
856 856
857 Compiles debug level messages into the kernel, which would not 857 Compiles debug level messages into the kernel, which would not
858 otherwise be available at runtime. These messages can then be 858 otherwise be available at runtime. These messages can then be
859 enabled/disabled on a per module basis. This mechanism implicitly 859 enabled/disabled on a per module basis. This mechanism implicitly
860 enables all pr_debug() and dev_dbg() calls. The impact of this 860 enables all pr_debug() and dev_dbg() calls. The impact of this
861 compile option is a larger kernel text size of about 2%. 861 compile option is a larger kernel text size of about 2%.
862 862
863 Usage: 863 Usage:
864 864
865 Dynamic debugging is controlled by the debugfs file, 865 Dynamic debugging is controlled by the debugfs file,
866 dynamic_printk/modules. This file contains a list of the modules that 866 dynamic_printk/modules. This file contains a list of the modules that
867 can be enabled. The format of the file is the module name, followed 867 can be enabled. The format of the file is the module name, followed
868 by a set of flags that can be enabled. The first flag is always the 868 by a set of flags that can be enabled. The first flag is always the
869 'enabled' flag. For example: 869 'enabled' flag. For example:
870 870
871 <module_name> <enabled=0/1> 871 <module_name> <enabled=0/1>
872 . 872 .
873 . 873 .
874 . 874 .
875 875
876 <module_name> : Name of the module in which the debug call resides 876 <module_name> : Name of the module in which the debug call resides
877 <enabled=0/1> : whether the messages are enabled or not 877 <enabled=0/1> : whether the messages are enabled or not
878 878
879 From a live system: 879 From a live system:
880 880
881 snd_hda_intel enabled=0 881 snd_hda_intel enabled=0
882 fixup enabled=0 882 fixup enabled=0
883 driver enabled=0 883 driver enabled=0
884 884
885 Enable a module: 885 Enable a module:
886 886
887 $echo "set enabled=1 <module_name>" > dynamic_printk/modules 887 $echo "set enabled=1 <module_name>" > dynamic_printk/modules
888 888
889 Disable a module: 889 Disable a module:
890 890
891 $echo "set enabled=0 <module_name>" > dynamic_printk/modules 891 $echo "set enabled=0 <module_name>" > dynamic_printk/modules
892 892
893 Enable all modules: 893 Enable all modules:
894 894
895 $echo "set enabled=1 all" > dynamic_printk/modules 895 $echo "set enabled=1 all" > dynamic_printk/modules
896 896
897 Disable all modules: 897 Disable all modules:
898 898
899 $echo "set enabled=0 all" > dynamic_printk/modules 899 $echo "set enabled=0 all" > dynamic_printk/modules
900 900
901 Finally, passing "dynamic_printk" at the command line enables 901 Finally, passing "dynamic_printk" at the command line enables
902 debugging for all modules. This mode can be turned off via the above 902 debugging for all modules. This mode can be turned off via the above
903 disable command. 903 disable command.
904 904
905 config DMA_API_DEBUG
906 bool "Enable debugging of DMA-API usage"
907 depends on HAVE_DMA_API_DEBUG
908 help
909 Enable this option to debug the use of the DMA API by device drivers.
910 With this option you will be able to detect common bugs in device
911 drivers like double-freeing of DMA mappings or freeing mappings that
912 were never allocated.
913 This option causes a performance degredation. Use only if you want
914 to debug device drivers. If unsure, say N.
915
905 source "samples/Kconfig" 916 source "samples/Kconfig"
906 917
907 source "lib/Kconfig.kgdb" 918 source "lib/Kconfig.kgdb"
908 919