- 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.