I am trying to debug the kernel on remote target, the AM3359 but my first break point works at the entry point of kernel, after that the processor do not accept any other break point. I am a newbie on arm but I think that I have to change the state from microprocessor, something like "debug mode" so that I can use break points.
I did a test using an standalone program with no problem but I think that linux set something at the beginning that makes break points or single step impossible.
78 .arm
79
80 __HEAD
81 ENTRY(stext)
82
83 THUMB( adr r9, BSYM(1f) ) @ Kernel is always entered in ARM.
84 THUMB( bx r9 ) @ If this is a Thumb-2 kernel, <=================== The only break point that works
85 THUMB( .thumb ) @ switch to Thumb now.
86 THUMB(1: )
87
88 setmode PSR_F_BIT | PSR_I_BIT | SVC_MODE, r9 @ ensure svc mode
89 @ and irqs disabled
90 mrc p15, 0, r9, c0, c0 @ get processor id
91 bl __lookup_processor_type @ r5=procinfo r9=cpuid
92 movs r10, r5 @ invalid processor (r5=0)?
93 THUMB( it eq ) @ force fixup-able long branch encoding
94 beq __error_p @ yes, error 'p'
I have been digging at ARM documentation but I don't understand how to change the cpu to debug mode. Maybe the line 88 is setting the condition.
Any help is welcome.
