[net-next-2.6.git] / arch / blackfin / Kconfig.debug

menu "Kernel hacking"

source "lib/Kconfig.debug"

config DEBUG_STACKOVERFLOW
	bool "Check for stack overflows"
	depends on DEBUG_KERNEL
	help
	  This option will cause messages to be printed if free stack space
	  drops below a certain limit.

config DEBUG_STACK_USAGE
	bool "Enable stack utilization instrumentation"
	depends on DEBUG_KERNEL
	help
	  Enables the display of the minimum amount of free stack which each
	  task has ever had available in the sysrq-T output.

	  This option will slow down process creation somewhat.

config DEBUG_VERBOSE
	bool "Verbose fault messages"
	default y
	select PRINTK
	help
	  When a program crashes due to an exception, or the kernel detects
	  an internal error, the kernel can print a not so brief message
	  explaining what the problem was. This debugging information is
	  useful to developers and kernel hackers when tracking down problems,
	  but mostly meaningless to other people. This is always helpful for
	  debugging but serves no purpose on a production system.
	  Most people should say N here.

config DEBUG_MMRS
	bool "Generate Blackfin MMR tree"
	select DEBUG_FS
	help
	  Create a tree of Blackfin MMRs via the debugfs tree.  If
	  you enable this, you will find all MMRs laid out in the
	  /sys/kernel/debug/blackfin/ directory where you can read/write
	  MMRs directly from userspace.  This is obviously just a debug
	  feature.

config DEBUG_HWERR
	bool "Hardware error interrupt debugging"
	depends on DEBUG_KERNEL
	help
	  When enabled, the hardware error interrupt is never disabled, and
	  will happen immediately when an error condition occurs.  This comes
	  at a slight cost in code size, but is necessary if you are getting
	  hardware error interrupts and need to know where they are coming
	  from.

config EXACT_HWERR
	bool "Try to make Hardware errors exact"
	depends on DEBUG_HWERR
	help
	  By default, the Blackfin hardware errors are not exact - the error
          be reported multiple cycles after the error happens. This delay
	  can cause the wrong application, or even the kernel to receive a
	  signal to be killed. If you are getting HW errors in your system,
	  try turning this on to ensure they are at least comming from the
	  proper thread.

	  On production systems, it is safe (and a small optimization) to say N.

config DEBUG_DOUBLEFAULT
	bool "Debug Double Faults"
	default n
	help
	  If an exception is caused while executing code within the exception
	  handler, the NMI handler, the reset vector, or in emulator mode,
	  a double fault occurs. On the Blackfin, this is a unrecoverable
	  event. You have two options:
	  - RESET exactly when double fault occurs. The excepting
	    instruction address is stored in RETX, where the next kernel
	    boot will print it out.
	  - Print debug message. This is much more error prone, although
	    easier to handle. It is error prone since:
	    - The excepting instruction is not committed.
	    - All writebacks from the instruction are prevented.
	    - The generated exception is not taken.
	    - The EXCAUSE field is updated with an unrecoverable event
	    The only way to check this is to see if EXCAUSE contains the
	    unrecoverable event value at every exception return. By selecting
	    this option, you are skipping over the faulting instruction, and 
	    hoping things stay together enough to print out a debug message.

	  This does add a little kernel code, but is the only method to debug
	  double faults - if unsure say "Y"

choice
	prompt "Double Fault Failure Method"
	default DEBUG_DOUBLEFAULT_PRINT
	depends on DEBUG_DOUBLEFAULT

config DEBUG_DOUBLEFAULT_PRINT
	bool "Print"

config DEBUG_DOUBLEFAULT_RESET
	bool "Reset"

endchoice

config DEBUG_HUNT_FOR_ZERO
	bool "Catch NULL pointer reads/writes"
	default y
	help
	  Say Y here to catch reads/writes to anywhere in the memory range
	  from 0x0000 - 0x0FFF (the first 4k) of memory.  This is useful in
	  catching common programming errors such as NULL pointer dereferences.

	  Misbehaving applications will be killed (generate a SEGV) while the
	  kernel will trigger a panic.

	  Enabling this option will take up an extra entry in CPLB table.
	  Otherwise, there is no extra overhead.

config DEBUG_BFIN_HWTRACE_ON
	bool "Turn on Blackfin's Hardware Trace"
	default y
	help
	  All Blackfins include a Trace Unit which stores a history of the last
	  16 changes in program flow taken by the program sequencer. The history
	  allows the user to recreate the program sequencer’s recent path. This
	  can be handy when an application dies - we print out the execution
	  path of how it got to the offending instruction.

	  By turning this off, you may save a tiny amount of power.

choice
	prompt "Omit loop Tracing"
	default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
	depends on DEBUG_BFIN_HWTRACE_ON
	help
	  The trace buffer can be configured to omit recording of changes in
	  program flow that match either the last entry or one of the last
	  two entries. Omitting one of these entries from the record prevents
	  the trace buffer from overflowing because of any sort of loop (for, do
	  while, etc) in the program.

	  Because zero-overhead Hardware loops are not recorded in the trace buffer,
	  this feature can be used to prevent trace overflow from loops that
	  are nested four deep.

config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
	bool "Trace all Loops"
	help
	  The trace buffer records all changes of flow 

config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
	bool "Compress single-level loops"
	help
	  The trace buffer does not record single loops - helpful if trace 
	  is spinning on a while or do loop.

config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
	bool "Compress two-level loops"
	help
	  The trace buffer does not record loops two levels deep. Helpful if
	  the trace is spinning in a nested loop

endchoice

config DEBUG_BFIN_HWTRACE_COMPRESSION
	int
	depends on DEBUG_BFIN_HWTRACE_ON
	default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
	default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
	default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO


config DEBUG_BFIN_HWTRACE_EXPAND
	bool "Expand Trace Buffer greater than 16 entries"
	depends on DEBUG_BFIN_HWTRACE_ON
	default n
	help
	  By selecting this option, every time the 16 hardware entries in
	  the Blackfin's HW Trace buffer are full, the kernel will move them
	  into a software buffer, for dumping when there is an issue. This 
	  has a great impact on performance, (an interrupt every 16 change of 
	  flows) and should normally be turned off, except in those nasty
	  debugging sessions

config DEBUG_BFIN_HWTRACE_EXPAND_LEN
	int "Size of Trace buffer (in power of 2k)"
	range 0 4
	depends on DEBUG_BFIN_HWTRACE_EXPAND
	default 1
	help
	  This sets the size of the software buffer that the trace information
	  is kept in.
	  0 for (2^0)  1k, or 256 entries,
	  1 for (2^1)  2k, or 512 entries,
	  2 for (2^2)  4k, or 1024 entries,
	  3 for (2^3)  8k, or 2048 entries,
	  4 for (2^4) 16k, or 4096 entries

config DEBUG_BFIN_NO_KERN_HWTRACE
	bool "Turn off hwtrace in CPLB handlers"
	depends on DEBUG_BFIN_HWTRACE_ON
	default y
	help
	  The CPLB error handler contains a lot of flow changes which can
	  quickly fill up the hardware trace buffer.  When debugging crashes,
	  the hardware trace may indicate that the problem lies in kernel
	  space when in reality an application is buggy.

	  Say Y here to disable hardware tracing in some known "jumpy" pieces
	  of code so that the trace buffer will extend further back.

config EARLY_PRINTK
	bool "Early printk" 
	default n
	select SERIAL_CORE_CONSOLE
	help
	  This option enables special console drivers which allow the kernel
	  to print messages very early in the bootup process.

	  This is useful for kernel debugging when your machine crashes very
	  early before the console code is initialized. After enabling this
	  feature, you must add "earlyprintk=serial,uart0,57600" to the
	  command line (bootargs). It is safe to say Y here in all cases, as
	  all of this lives in the init section and is thrown away after the
	  kernel boots completely.

config NMI_WATCHDOG
	bool "Enable NMI watchdog to help debugging lockup on SMP"
	default n
	depends on SMP
	help
	  If any CPU in the system does not execute the period local timer
	  interrupt for more than 5 seconds, then the NMI handler dumps debug
	  information. This information can be used to debug the lockup.

config CPLB_INFO
	bool "Display the CPLB information"
	help
	  Display the CPLB information via /proc/cplbinfo.

config ACCESS_CHECK
	bool "Check the user pointer address"
	default y
	help
	  Usually the pointer transfer from user space is checked to see if its
	  address is in the kernel space.

	  Say N here to disable that check to improve the performance.

config BFIN_ISRAM_SELF_TEST
	bool "isram boot self tests"
	default n
	help
	  Run some self tests of the isram driver code at boot.

config BFIN_PSEUDODBG_INSNS
	bool "Support pseudo debug instructions"
	default n
	help
	  This option allows the kernel to emulate some pseudo instructions which
	  allow simulator test cases to be run under Linux with no changes.

	  Most people should say N here.

endmenu
Commit	Line	Data
74ce8322 MF	1	menu "Kernel hacking"
	2
	3	source "lib/Kconfig.debug"
	4
a45d575f RG	5	config DEBUG_STACKOVERFLOW
	6	bool "Check for stack overflows"
	7	depends on DEBUG_KERNEL
	8	help
	9	This option will cause messages to be printed if free stack space
	10	drops below a certain limit.
	11
	12	config DEBUG_STACK_USAGE
	13	bool "Enable stack utilization instrumentation"
	14	depends on DEBUG_KERNEL
	15	help
	16	Enables the display of the minimum amount of free stack which each
	17	task has ever had available in the sysrq-T output.
	18
	19	This option will slow down process creation somewhat.
	20
9f06c38f RG	21	config DEBUG_VERBOSE
	22	bool "Verbose fault messages"
	23	default y
	24	select PRINTK
	25	help
	26	When a program crashes due to an exception, or the kernel detects
	27	an internal error, the kernel can print a not so brief message
	28	explaining what the problem was. This debugging information is
	29	useful to developers and kernel hackers when tracking down problems,
	30	but mostly meaningless to other people. This is always helpful for
	31	debugging but serves no purpose on a production system.
	32	Most people should say N here.
	33
74ce8322 MF	34	config DEBUG_MMRS
	35	bool "Generate Blackfin MMR tree"
	36	select DEBUG_FS
	37	help
	38	Create a tree of Blackfin MMRs via the debugfs tree. If
	39	you enable this, you will find all MMRs laid out in the
	40	/sys/kernel/debug/blackfin/ directory where you can read/write
	41	MMRs directly from userspace. This is obviously just a debug
	42	feature.
	43
	44	config DEBUG_HWERR
	45	bool "Hardware error interrupt debugging"
	46	depends on DEBUG_KERNEL
	47	help
	48	When enabled, the hardware error interrupt is never disabled, and
	49	will happen immediately when an error condition occurs. This comes
	50	at a slight cost in code size, but is necessary if you are getting
	51	hardware error interrupts and need to know where they are coming
	52	from.
	53
b9a3899d RG	54	config EXACT_HWERR
	55	bool "Try to make Hardware errors exact"
	56	depends on DEBUG_HWERR
	57	help
	58	By default, the Blackfin hardware errors are not exact - the error
	59	be reported multiple cycles after the error happens. This delay
	60	can cause the wrong application, or even the kernel to receive a
	61	signal to be killed. If you are getting HW errors in your system,
	62	try turning this on to ensure they are at least comming from the
	63	proper thread.
	64
	65	On production systems, it is safe (and a small optimization) to say N.
	66
0c7a6b21 RG	67	config DEBUG_DOUBLEFAULT
	68	bool "Debug Double Faults"
	69	default n
	70	help
	71	If an exception is caused while executing code within the exception
	72	handler, the NMI handler, the reset vector, or in emulator mode,
	73	a double fault occurs. On the Blackfin, this is a unrecoverable
	74	event. You have two options:
	75	- RESET exactly when double fault occurs. The excepting
	76	instruction address is stored in RETX, where the next kernel
	77	boot will print it out.
	78	- Print debug message. This is much more error prone, although
	79	easier to handle. It is error prone since:
	80	- The excepting instruction is not committed.
	81	- All writebacks from the instruction are prevented.
	82	- The generated exception is not taken.
	83	- The EXCAUSE field is updated with an unrecoverable event
	84	The only way to check this is to see if EXCAUSE contains the
	85	unrecoverable event value at every exception return. By selecting
	86	this option, you are skipping over the faulting instruction, and
	87	hoping things stay together enough to print out a debug message.
	88
	89	This does add a little kernel code, but is the only method to debug
	90	double faults - if unsure say "Y"
	91
	92	choice
	93	prompt "Double Fault Failure Method"
	94	default DEBUG_DOUBLEFAULT_PRINT
	95	depends on DEBUG_DOUBLEFAULT
	96
	97	config DEBUG_DOUBLEFAULT_PRINT
	98	bool "Print"
	99
	100	config DEBUG_DOUBLEFAULT_RESET
	101	bool "Reset"
	102
	103	endchoice
	104
74ce8322 MF	105	config DEBUG_HUNT_FOR_ZERO
	106	bool "Catch NULL pointer reads/writes"
	107	default y
	108	help
	109	Say Y here to catch reads/writes to anywhere in the memory range
	110	from 0x0000 - 0x0FFF (the first 4k) of memory. This is useful in
	111	catching common programming errors such as NULL pointer dereferences.
	112
	113	Misbehaving applications will be killed (generate a SEGV) while the
	114	kernel will trigger a panic.
	115
	116	Enabling this option will take up an extra entry in CPLB table.
	117	Otherwise, there is no extra overhead.
	118
	119	config DEBUG_BFIN_HWTRACE_ON
	120	bool "Turn on Blackfin's Hardware Trace"
	121	default y
	122	help
	123	All Blackfins include a Trace Unit which stores a history of the last
	124	16 changes in program flow taken by the program sequencer. The history
	125	allows the user to recreate the program sequencer’s recent path. This
	126	can be handy when an application dies - we print out the execution
	127	path of how it got to the offending instruction.
	128
	129	By turning this off, you may save a tiny amount of power.
	130
	131	choice
	132	prompt "Omit loop Tracing"
	133	default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
	134	depends on DEBUG_BFIN_HWTRACE_ON
	135	help
	136	The trace buffer can be configured to omit recording of changes in
	137	program flow that match either the last entry or one of the last
	138	two entries. Omitting one of these entries from the record prevents
	139	the trace buffer from overflowing because of any sort of loop (for, do
	140	while, etc) in the program.
	141
	142	Because zero-overhead Hardware loops are not recorded in the trace buffer,
	143	this feature can be used to prevent trace overflow from loops that
	144	are nested four deep.
	145
	146	config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
	147	bool "Trace all Loops"
	148	help
	149	The trace buffer records all changes of flow
	150
	151	config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
	152	bool "Compress single-level loops"
	153	help
	154	The trace buffer does not record single loops - helpful if trace
	155	is spinning on a while or do loop.
	156
	157	config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
	158	bool "Compress two-level loops"
	159	help
	160	The trace buffer does not record loops two levels deep. Helpful if
	161	the trace is spinning in a nested loop
	162
	163	endchoice
	164
	165	config DEBUG_BFIN_HWTRACE_COMPRESSION
	166	int
	167	depends on DEBUG_BFIN_HWTRACE_ON
	168	default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
169	default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
170	default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
171
172
173	config DEBUG_BFIN_HWTRACE_EXPAND
174	bool "Expand Trace Buffer greater than 16 entries"
175	depends on DEBUG_BFIN_HWTRACE_ON
176	default n
177	help
178	By selecting this option, every time the 16 hardware entries in
179	the Blackfin's HW Trace buffer are full, the kernel will move them
180	into a software buffer, for dumping when there is an issue. This
181	has a great impact on performance, (an interrupt every 16 change of
182	flows) and should normally be turned off, except in those nasty
183	debugging sessions
184
185	config DEBUG_BFIN_HWTRACE_EXPAND_LEN
186	int "Size of Trace buffer (in power of 2k)"
187	range 0 4
188	depends on DEBUG_BFIN_HWTRACE_EXPAND
189	default 1
190	help
191	This sets the size of the software buffer that the trace information
192	is kept in.
193	0 for (2^0) 1k, or 256 entries,
194	1 for (2^1) 2k, or 512 entries,
195	2 for (2^2) 4k, or 1024 entries,
196	3 for (2^3) 8k, or 2048 entries,
197	4 for (2^4) 16k, or 4096 entries
198
199	config DEBUG_BFIN_NO_KERN_HWTRACE
e60cb8a9	200	bool "Turn off hwtrace in CPLB handlers"
74ce8322	201	depends on DEBUG_BFIN_HWTRACE_ON
e60cb8a9	202	default y
74ce8322	203	help
e60cb8a9	204	The CPLB error handler contains a lot of flow changes which can
74ce8322 MF	205	quickly fill up the hardware trace buffer. When debugging crashes,
	206	the hardware trace may indicate that the problem lies in kernel
	207	space when in reality an application is buggy.
	208
	209	Say Y here to disable hardware tracing in some known "jumpy" pieces
	210	of code so that the trace buffer will extend further back.
	211
	212	config EARLY_PRINTK
	213	bool "Early printk"
	214	default n
0cfbb323	215	select SERIAL_CORE_CONSOLE
74ce8322 MF	216	help
	217	This option enables special console drivers which allow the kernel
	218	to print messages very early in the bootup process.
	219
	220	This is useful for kernel debugging when your machine crashes very
	221	early before the console code is initialized. After enabling this
	222	feature, you must add "earlyprintk=serial,uart0,57600" to the
	223	command line (bootargs). It is safe to say Y here in all cases, as
	224	all of this lives in the init section and is thrown away after the
	225	kernel boots completely.
	226
60ffdb36 GY	227	config NMI_WATCHDOG
	228	bool "Enable NMI watchdog to help debugging lockup on SMP"
	229	default n
c429886a	230	depends on SMP
60ffdb36 GY	231	help
	232	If any CPU in the system does not execute the period local timer
	233	interrupt for more than 5 seconds, then the NMI handler dumps debug
	234	information. This information can be used to debug the lockup.
	235
74ce8322 MF	236	config CPLB_INFO
	237	bool "Display the CPLB information"
	238	help
cf93425d	239	Display the CPLB information via /proc/cplbinfo.
74ce8322 MF	240
	241	config ACCESS_CHECK
	242	bool "Check the user pointer address"
	243	default y
	244	help
	245	Usually the pointer transfer from user space is checked to see if its
	246	address is in the kernel space.
	247
	248	Say N here to disable that check to improve the performance.
	249
c40cdb2c MF	250	config BFIN_ISRAM_SELF_TEST
	251	bool "isram boot self tests"
	252	default n
	253	help
	254	Run some self tests of the isram driver code at boot.
	255
6ce3e9c2 RG	256	config BFIN_PSEUDODBG_INSNS
	257	bool "Support pseudo debug instructions"
	258	default n
	259	help
	260	This option allows the kernel to emulate some pseudo instructions which
	261	allow simulator test cases to be run under Linux with no changes.
	262
	263	Most people should say N here.
	264
74ce8322	265	endmenu