Hw-breakpoint: shared debugging registers
Posted Sep 25, 2009 18:33 UTC (Fri) by HalfMoon
Parent article: Hw-breakpoint: shared debugging registers
I'll be skeptical about the framework untill I see it working with three different hardware implementations ... and working with GDB. Such things can be tricky to get right!
After x86, I'd suggest the EmbeddedICE as seen on ARM9 chips ... Linux will need to implement an in-kernel debug monitor. ARM9 chips, notably ARM926, are extremely common. An alternative might be the newer Cortex-A8 chips; extremely interesting, and with far richer debug hardware, but for the moment they're only really visible in OMAP3 chips (and thus for example BeagleBoard.org hardware).
One issue there will be how to interact with JTAG debuggers. Better maybe to call it an "opportunity"; this might be the guts of the hook needed for tools like OpenOCD to support debugging of non-kernel code.
ARM hardware has some pretty serious integrated hardware debug tools. Does x86 include stuff like an Embedded Trace Module (ETM)? On ARM those sometimes hook up to the breakpoint/watchpoint hardware to get a few more sources of trace triggers. You can do things like record per-instruction costs for the Nth invocation of a given function. Presumably this work would eventually want to coexist with that too.
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