[linux-2.6-block.git] / arch / blackfin / Kconfig.debug

menu "Kernel hacking"

source "lib/Kconfig.debug"

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
	tristate "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 coming 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.

config BFIN_PM_WAKEUP_TIME_BENCH
	bool "Display the total time for kernel to resume from power saving mode"
	default n
	help
	  Display the total time when kernel resumes normal from standby or
	  suspend to mem mode.

endmenu
Commit	Line	Data
74ce8322 MF	1	menu "Kernel hacking"
	2
	3	source "lib/Kconfig.debug"
	4
9f06c38f RG	5	config DEBUG_VERBOSE
	6	bool "Verbose fault messages"
	7	default y
	8	select PRINTK
	9	help
	10	When a program crashes due to an exception, or the kernel detects
	11	an internal error, the kernel can print a not so brief message
	12	explaining what the problem was. This debugging information is
	13	useful to developers and kernel hackers when tracking down problems,
	14	but mostly meaningless to other people. This is always helpful for
	15	debugging but serves no purpose on a production system.
	16	Most people should say N here.
	17
74ce8322	18	config DEBUG_MMRS
73ecfcf9	19	tristate "Generate Blackfin MMR tree"
74ce8322 MF	20	select DEBUG_FS
	21	help
	22	Create a tree of Blackfin MMRs via the debugfs tree. If
	23	you enable this, you will find all MMRs laid out in the
	24	/sys/kernel/debug/blackfin/ directory where you can read/write
	25	MMRs directly from userspace. This is obviously just a debug
	26	feature.
	27
	28	config DEBUG_HWERR
	29	bool "Hardware error interrupt debugging"
	30	depends on DEBUG_KERNEL
	31	help
	32	When enabled, the hardware error interrupt is never disabled, and
	33	will happen immediately when an error condition occurs. This comes
	34	at a slight cost in code size, but is necessary if you are getting
	35	hardware error interrupts and need to know where they are coming
	36	from.
	37
b9a3899d RG	38	config EXACT_HWERR
	39	bool "Try to make Hardware errors exact"
	40	depends on DEBUG_HWERR
	41	help
	42	By default, the Blackfin hardware errors are not exact - the error
	43	be reported multiple cycles after the error happens. This delay
	44	can cause the wrong application, or even the kernel to receive a
	45	signal to be killed. If you are getting HW errors in your system,
25985edc	46	try turning this on to ensure they are at least coming from the
b9a3899d RG	47	proper thread.
	48
	49	On production systems, it is safe (and a small optimization) to say N.
	50
0c7a6b21 RG	51	config DEBUG_DOUBLEFAULT
	52	bool "Debug Double Faults"
	53	default n
	54	help
	55	If an exception is caused while executing code within the exception
	56	handler, the NMI handler, the reset vector, or in emulator mode,
	57	a double fault occurs. On the Blackfin, this is a unrecoverable
	58	event. You have two options:
	59	- RESET exactly when double fault occurs. The excepting
	60	instruction address is stored in RETX, where the next kernel
	61	boot will print it out.
	62	- Print debug message. This is much more error prone, although
	63	easier to handle. It is error prone since:
	64	- The excepting instruction is not committed.
	65	- All writebacks from the instruction are prevented.
	66	- The generated exception is not taken.
	67	- The EXCAUSE field is updated with an unrecoverable event
	68	The only way to check this is to see if EXCAUSE contains the
	69	unrecoverable event value at every exception return. By selecting
	70	this option, you are skipping over the faulting instruction, and
	71	hoping things stay together enough to print out a debug message.
	72
	73	This does add a little kernel code, but is the only method to debug
	74	double faults - if unsure say "Y"
	75
	76	choice
	77	prompt "Double Fault Failure Method"
	78	default DEBUG_DOUBLEFAULT_PRINT
	79	depends on DEBUG_DOUBLEFAULT
	80
	81	config DEBUG_DOUBLEFAULT_PRINT
	82	bool "Print"
	83
	84	config DEBUG_DOUBLEFAULT_RESET
	85	bool "Reset"
	86
	87	endchoice
	88
74ce8322 MF	89	config DEBUG_HUNT_FOR_ZERO
	90	bool "Catch NULL pointer reads/writes"
	91	default y
	92	help
	93	Say Y here to catch reads/writes to anywhere in the memory range
	94	from 0x0000 - 0x0FFF (the first 4k) of memory. This is useful in
	95	catching common programming errors such as NULL pointer dereferences.
	96
	97	Misbehaving applications will be killed (generate a SEGV) while the
	98	kernel will trigger a panic.
	99
	100	Enabling this option will take up an extra entry in CPLB table.
	101	Otherwise, there is no extra overhead.
	102
	103	config DEBUG_BFIN_HWTRACE_ON
	104	bool "Turn on Blackfin's Hardware Trace"
	105	default y
	106	help
	107	All Blackfins include a Trace Unit which stores a history of the last
	108	16 changes in program flow taken by the program sequencer. The history
	109	allows the user to recreate the program sequencer’s recent path. This
	110	can be handy when an application dies - we print out the execution
	111	path of how it got to the offending instruction.
	112
	113	By turning this off, you may save a tiny amount of power.
	114
	115	choice
	116	prompt "Omit loop Tracing"
	117	default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
	118	depends on DEBUG_BFIN_HWTRACE_ON
	119	help
	120	The trace buffer can be configured to omit recording of changes in
	121	program flow that match either the last entry or one of the last
	122	two entries. Omitting one of these entries from the record prevents
	123	the trace buffer from overflowing because of any sort of loop (for, do
	124	while, etc) in the program.
	125
	126	Because zero-overhead Hardware loops are not recorded in the trace buffer,
	127	this feature can be used to prevent trace overflow from loops that
	128	are nested four deep.
	129
	130	config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
	131	bool "Trace all Loops"
	132	help
	133	The trace buffer records all changes of flow
	134
	135	config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
	136	bool "Compress single-level loops"
	137	help
	138	The trace buffer does not record single loops - helpful if trace
	139	is spinning on a while or do loop.
	140
	141	config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
	142	bool "Compress two-level loops"
	143	help
	144	The trace buffer does not record loops two levels deep. Helpful if
	145	the trace is spinning in a nested loop
	146
	147	endchoice
	148
	149	config DEBUG_BFIN_HWTRACE_COMPRESSION
	150	int
	151	depends on DEBUG_BFIN_HWTRACE_ON
	152	default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
153	default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
154	default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
155
156
157	config DEBUG_BFIN_HWTRACE_EXPAND
158	bool "Expand Trace Buffer greater than 16 entries"
159	depends on DEBUG_BFIN_HWTRACE_ON
160	default n
161	help
162	By selecting this option, every time the 16 hardware entries in
163	the Blackfin's HW Trace buffer are full, the kernel will move them
164	into a software buffer, for dumping when there is an issue. This
165	has a great impact on performance, (an interrupt every 16 change of
166	flows) and should normally be turned off, except in those nasty
167	debugging sessions
168
169	config DEBUG_BFIN_HWTRACE_EXPAND_LEN
170	int "Size of Trace buffer (in power of 2k)"
171	range 0 4
172	depends on DEBUG_BFIN_HWTRACE_EXPAND
173	default 1
174	help
175	This sets the size of the software buffer that the trace information
176	is kept in.
177	0 for (2^0) 1k, or 256 entries,
178	1 for (2^1) 2k, or 512 entries,
179	2 for (2^2) 4k, or 1024 entries,
180	3 for (2^3) 8k, or 2048 entries,
181	4 for (2^4) 16k, or 4096 entries
182
183	config DEBUG_BFIN_NO_KERN_HWTRACE
e60cb8a9	184	bool "Turn off hwtrace in CPLB handlers"
74ce8322	185	depends on DEBUG_BFIN_HWTRACE_ON
e60cb8a9	186	default y
74ce8322	187	help
e60cb8a9	188	The CPLB error handler contains a lot of flow changes which can
74ce8322 MF	189	quickly fill up the hardware trace buffer. When debugging crashes,
	190	the hardware trace may indicate that the problem lies in kernel
	191	space when in reality an application is buggy.
	192
	193	Say Y here to disable hardware tracing in some known "jumpy" pieces
	194	of code so that the trace buffer will extend further back.
	195
	196	config EARLY_PRINTK
	197	bool "Early printk"
	198	default n
0cfbb323	199	select SERIAL_CORE_CONSOLE
74ce8322 MF	200	help
	201	This option enables special console drivers which allow the kernel
	202	to print messages very early in the bootup process.
	203
	204	This is useful for kernel debugging when your machine crashes very
	205	early before the console code is initialized. After enabling this
	206	feature, you must add "earlyprintk=serial,uart0,57600" to the
	207	command line (bootargs). It is safe to say Y here in all cases, as
	208	all of this lives in the init section and is thrown away after the
	209	kernel boots completely.
	210
60ffdb36 GY	211	config NMI_WATCHDOG
	212	bool "Enable NMI watchdog to help debugging lockup on SMP"
	213	default n
c429886a	214	depends on SMP
60ffdb36 GY	215	help
	216	If any CPU in the system does not execute the period local timer
	217	interrupt for more than 5 seconds, then the NMI handler dumps debug
	218	information. This information can be used to debug the lockup.
	219
74ce8322 MF	220	config CPLB_INFO
	221	bool "Display the CPLB information"
	222	help
cf93425d	223	Display the CPLB information via /proc/cplbinfo.
74ce8322 MF	224
	225	config ACCESS_CHECK
	226	bool "Check the user pointer address"
	227	default y
	228	help
	229	Usually the pointer transfer from user space is checked to see if its
	230	address is in the kernel space.
	231
	232	Say N here to disable that check to improve the performance.
	233
c40cdb2c MF	234	config BFIN_ISRAM_SELF_TEST
	235	bool "isram boot self tests"
	236	default n
	237	help
	238	Run some self tests of the isram driver code at boot.
	239
6ce3e9c2 RG	240	config BFIN_PSEUDODBG_INSNS
	241	bool "Support pseudo debug instructions"
	242	default n
	243	help
	244	This option allows the kernel to emulate some pseudo instructions which
	245	allow simulator test cases to be run under Linux with no changes.
	246
	247	Most people should say N here.
	248
72b099ed SZ	249	config BFIN_PM_WAKEUP_TIME_BENCH
	250	bool "Display the total time for kernel to resume from power saving mode"
	251	default n
	252	help
	253	Display the total time when kernel resumes normal from standby or
	254	suspend to mem mode.
	255
74ce8322	256	endmenu