FAQ for RTOS-LINUX The embedded tools company
"MMU.FORMAT LINUX swapper_pg_dir"
"SYstem.Option MMU ON/OFF" Error
Linux trace in simulator
Problems with Software Breakpoints
TASK.MODULE Display Problems



FAQ for RTOS-LINUX

TOP       "MMU.FORMAT LINUX swapper_pg_dir"
Why does "MMU.FORMAT LINUX swapper_pg_dir" report "invalid combination"?
 
Space IDs must be switched on for this command to work: "SYStem.Option MMUSPACES ON".

TOP       "SYstem.Option MMU ON/OFF" Error
Why does "SYstem.Option MMU ON/OFF" report "Cannot change from short to long"?
 
This command executes only, if no symbols are loaded. Delete previous loaded symbols with "sYmbol.Delete".

TOP       Linux trace in simulator
What is needed to revise a Linux trace with a TRACE32 instruction set simulator?
 
Example for ARM926

SAVING IN TRACE32 DEBUGGER:
Trace.SAVE trace.ad                                     ; save trace recording
Data.SAVE.Binary image.bin ASD:address_range            ; save whole Linux address range
                                                        ; including code area, data area and MMU table
Data.SAVE.Binary p15.bin C15:0x0--0xfff /Long           ; save important CP15 registers



LOADING IN TRACE32 INSTRUCTION SET SIMULATOR:
SYStem.RESet
SYStem.CPU ARM926
SYStem.Option MMUspaces ON                              ; enable space-id
System.Up                                               ; establish the communication between ARM926 and
                                                        ; the debugger
Data.LOAD.Binary image.bin ASD:address_range            ; load Linux image
Data.LOAD.Binary cp15.bin c15:0                         ; load important CP15 registers

Data.LOAD.Elf vmlinux /GNU /NOCODE                      ; load symbol information

; specifiy MMU table format
MMU.FORMAT linux swapper_pg_dir 0xc0000000--0xc1ffffff  kernel_load_address
MMU.Create 0xc0000000--0xc1ffffff  kernel_load_address
MMU.COMMON 0xc000000--0xfffffff
MMU.ON
MMU.SCANALL                                             ; rescan MMU table

TASK.CONFIG linux                                       ; configure Linux awareness
Menu.ReProgram linux
Help.Filter.ADD rtoslinux

Trace.LOAD trace.ad                                     ; load trace recording


TOP       Problems with Software Breakpoints
After halting at a function entry point with an on-chip breakpoint, or after stepping into a new function, the Data.List window shows "???"for all assembler lines, even after rescanning the MMU.
 
You probably fell over the demand paging mechanism of Linux.
Please read the "n-Demand Paging" chapter in the Linux Awareness Manual.

TOP       TASK.MODULE Display Problems
After loading a new kernel module, TASK.MODULE shows nothing, dashed lines or errors.
 
The target MMU is changed when loading kernel modules. Rescan the target MMU with MMU.SCANALL.



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Copyright © 2008 Lauterbach Datentechnik GmbH, Fichtenstr. 27, D-85649 Hofolding, Germany  Impressum
The information presented is intended to give overview information only.
Changes and technical enhancements or modifications can be made without notice.
Last generated/modified: Nov-4-2008