Debug ARM semihosting Thumb-2 binary

[Jonas Maebe <jonas dot maebe at elis dot ugent dot be>]

Hi,

I'm debugging ARM binaries compiled for the semihosting interface (http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/CHDJHHDI.html 
 ). The binaries run under qemu-system-arm and I'm using QEMU's gdb  
remote target interface.

In general, this works fine, except when such binaries are Thumb-2 and  
perform system calls. The reason is that for Thumb-2, the system call  
interface of the semihosting platform uses "bkpt 0xab" (http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0491c/CJAFABBB.html 
 ). GDB intercepts this bkpt, halts the execution with a SIGINT  
message and does not pass it on to the debugged process. If the  
process is then continued, it behaves as if the system call/bkpt in  
question never was executed

Using "handle SIGINT pass" does not change this.

Is there another way to tell gdb to ignore those particular bkpt  
instructions and execute them normally? I'm using gdb 7.4 (7.2 behaves  
the same).

Thanks,


Jonas