| 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 |