Re: m68k, signals and single-stepping

Andreas Schwab
2010-09-30T08:21:50Z

Geert Uytterhoeven <geert@linux-m68k.org> writes:

>> So what's that SIGTRAP on exit from syscall in single-stepping mode for?

The trace exception is low priority exception that is executed after all
other exceptions are processed. So if the cpu single steps over a trap
insns, the trace exception processing is started when the trap exception
processing is complete, which is just before the cpu starts executing
the trap exception handler in the kernel. You want the SIGTRAP to be
sent to the user process, so you have to delay sending it until the
kernel returns to user space.