[deliverable/linux.git] / arch / blackfin / Kconfig.debug

menu "Kernel hacking"

source "lib/Kconfig.debug"

config HAVE_ARCH_KGDB
       def_bool y

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 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_ICACHE_CHECK
	bool "Check Instruction cache coherency"
	depends on DEBUG_KERNEL
	depends on DEBUG_HWERR
	help
	  Say Y here if you are getting weird unexplained errors. This will
	  ensure that icache is what SDRAM says it should be by doing a
	  byte wise comparison between SDRAM and instruction cache. This
	  also relocates the irq_panic() function to L1 memory, (which is
	  un-cached).

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 "Trace user apps (turn off hwtrace in kernel)"
	depends on DEBUG_BFIN_HWTRACE_ON
	default n
	help
	  Some pieces of the kernel contain 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
	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 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.

endmenu
Commit	Line	Data
74ce8322 MF	1	menu "Kernel hacking"
	2
	3	source "lib/Kconfig.debug"
	4
a5ac0129 SZ	5	config HAVE_ARCH_KGDB
	6	def_bool y
	7
74ce8322 MF	8	config DEBUG_MMRS
	9	bool "Generate Blackfin MMR tree"
	10	select DEBUG_FS
	11	help
	12	Create a tree of Blackfin MMRs via the debugfs tree. If
	13	you enable this, you will find all MMRs laid out in the
	14	/sys/kernel/debug/blackfin/ directory where you can read/write
	15	MMRs directly from userspace. This is obviously just a debug
	16	feature.
	17
	18	config DEBUG_HWERR
	19	bool "Hardware error interrupt debugging"
	20	depends on DEBUG_KERNEL
	21	help
	22	When enabled, the hardware error interrupt is never disabled, and
	23	will happen immediately when an error condition occurs. This comes
	24	at a slight cost in code size, but is necessary if you are getting
	25	hardware error interrupts and need to know where they are coming
	26	from.
	27
0c7a6b21 RG	28	config DEBUG_DOUBLEFAULT
	29	bool "Debug Double Faults"
	30	default n
	31	help
	32	If an exception is caused while executing code within the exception
	33	handler, the NMI handler, the reset vector, or in emulator mode,
	34	a double fault occurs. On the Blackfin, this is a unrecoverable
	35	event. You have two options:
	36	- RESET exactly when double fault occurs. The excepting
	37	instruction address is stored in RETX, where the next kernel
	38	boot will print it out.
	39	- Print debug message. This is much more error prone, although
	40	easier to handle. It is error prone since:
	41	- The excepting instruction is not committed.
	42	- All writebacks from the instruction are prevented.
	43	- The generated exception is not taken.
	44	- The EXCAUSE field is updated with an unrecoverable event
	45	The only way to check this is to see if EXCAUSE contains the
	46	unrecoverable event value at every exception return. By selecting
	47	this option, you are skipping over the faulting instruction, and
	48	hoping things stay together enough to print out a debug message.
	49
	50	This does add a little kernel code, but is the only method to debug
	51	double faults - if unsure say "Y"
	52
	53	choice
	54	prompt "Double Fault Failure Method"
	55	default DEBUG_DOUBLEFAULT_PRINT
	56	depends on DEBUG_DOUBLEFAULT
	57
	58	config DEBUG_DOUBLEFAULT_PRINT
	59	bool "Print"
	60
	61	config DEBUG_DOUBLEFAULT_RESET
	62	bool "Reset"
	63
	64	endchoice
	65
74ce8322 MF	66	config DEBUG_ICACHE_CHECK
	67	bool "Check Instruction cache coherency"
	68	depends on DEBUG_KERNEL
	69	depends on DEBUG_HWERR
	70	help
	71	Say Y here if you are getting weird unexplained errors. This will
	72	ensure that icache is what SDRAM says it should be by doing a
	73	byte wise comparison between SDRAM and instruction cache. This
	74	also relocates the irq_panic() function to L1 memory, (which is
	75	un-cached).
	76
	77	config DEBUG_HUNT_FOR_ZERO
	78	bool "Catch NULL pointer reads/writes"
	79	default y
	80	help
	81	Say Y here to catch reads/writes to anywhere in the memory range
	82	from 0x0000 - 0x0FFF (the first 4k) of memory. This is useful in
	83	catching common programming errors such as NULL pointer dereferences.
	84
	85	Misbehaving applications will be killed (generate a SEGV) while the
	86	kernel will trigger a panic.
	87
	88	Enabling this option will take up an extra entry in CPLB table.
	89	Otherwise, there is no extra overhead.
	90
	91	config DEBUG_BFIN_HWTRACE_ON
	92	bool "Turn on Blackfin's Hardware Trace"
	93	default y
	94	help
	95	All Blackfins include a Trace Unit which stores a history of the last
	96	16 changes in program flow taken by the program sequencer. The history
	97	allows the user to recreate the program sequencer’s recent path. This
	98	can be handy when an application dies - we print out the execution
	99	path of how it got to the offending instruction.
	100
	101	By turning this off, you may save a tiny amount of power.
	102
	103	choice
	104	prompt "Omit loop Tracing"
	105	default DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
	106	depends on DEBUG_BFIN_HWTRACE_ON
	107	help
	108	The trace buffer can be configured to omit recording of changes in
	109	program flow that match either the last entry or one of the last
	110	two entries. Omitting one of these entries from the record prevents
	111	the trace buffer from overflowing because of any sort of loop (for, do
	112	while, etc) in the program.
	113
	114	Because zero-overhead Hardware loops are not recorded in the trace buffer,
	115	this feature can be used to prevent trace overflow from loops that
	116	are nested four deep.
	117
	118	config DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
	119	bool "Trace all Loops"
	120	help
	121	The trace buffer records all changes of flow
	122
	123	config DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
	124	bool "Compress single-level loops"
	125	help
	126	The trace buffer does not record single loops - helpful if trace
	127	is spinning on a while or do loop.
	128
	129	config DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
130	bool "Compress two-level loops"
131	help
132	The trace buffer does not record loops two levels deep. Helpful if
133	the trace is spinning in a nested loop
134
135	endchoice
136
137	config DEBUG_BFIN_HWTRACE_COMPRESSION
138	int
139	depends on DEBUG_BFIN_HWTRACE_ON
140	default 0 if DEBUG_BFIN_HWTRACE_COMPRESSION_OFF
141	default 1 if DEBUG_BFIN_HWTRACE_COMPRESSION_ONE
142	default 2 if DEBUG_BFIN_HWTRACE_COMPRESSION_TWO
143
144
145	config DEBUG_BFIN_HWTRACE_EXPAND
146	bool "Expand Trace Buffer greater than 16 entries"
147	depends on DEBUG_BFIN_HWTRACE_ON
148	default n
149	help
150	By selecting this option, every time the 16 hardware entries in
151	the Blackfin's HW Trace buffer are full, the kernel will move them
152	into a software buffer, for dumping when there is an issue. This
153	has a great impact on performance, (an interrupt every 16 change of
154	flows) and should normally be turned off, except in those nasty
155	debugging sessions
156
157	config DEBUG_BFIN_HWTRACE_EXPAND_LEN
158	int "Size of Trace buffer (in power of 2k)"
159	range 0 4
160	depends on DEBUG_BFIN_HWTRACE_EXPAND
161	default 1
162	help
163	This sets the size of the software buffer that the trace information
164	is kept in.
165	0 for (2^0) 1k, or 256 entries,
166	1 for (2^1) 2k, or 512 entries,
167	2 for (2^2) 4k, or 1024 entries,
168	3 for (2^3) 8k, or 2048 entries,
169	4 for (2^4) 16k, or 4096 entries
170
171	config DEBUG_BFIN_NO_KERN_HWTRACE
172	bool "Trace user apps (turn off hwtrace in kernel)"
173	depends on DEBUG_BFIN_HWTRACE_ON
174	default n
175	help
176	Some pieces of the kernel contain a lot of flow changes which can
177	quickly fill up the hardware trace buffer. When debugging crashes,
178	the hardware trace may indicate that the problem lies in kernel
179	space when in reality an application is buggy.
180
181	Say Y here to disable hardware tracing in some known "jumpy" pieces
182	of code so that the trace buffer will extend further back.
183
184	config EARLY_PRINTK
185	bool "Early printk"
186	default n
187	help
188	This option enables special console drivers which allow the kernel
189	to print messages very early in the bootup process.
190
191	This is useful for kernel debugging when your machine crashes very
192	early before the console code is initialized. After enabling this
193	feature, you must add "earlyprintk=serial,uart0,57600" to the
194	command line (bootargs). It is safe to say Y here in all cases, as
195	all of this lives in the init section and is thrown away after the
196	kernel boots completely.
197
74ce8322 MF	198	config CPLB_INFO
	199	bool "Display the CPLB information"
	200	help
cf93425d	201	Display the CPLB information via /proc/cplbinfo.
74ce8322 MF	202
	203	config ACCESS_CHECK
	204	bool "Check the user pointer address"
	205	default y
	206	help
	207	Usually the pointer transfer from user space is checked to see if its
	208	address is in the kernel space.
	209
	210	Say N here to disable that check to improve the performance.
	211
	212	endmenu