Hello Will, I've been trying to get GDB support for hardware watchpoints/breakpoints going. I've ported Matthew's GDB patch to current mainline, and am running this under a 2.6.37-1002-linaro-omap kernel on an IGEPv2 board.
However, something seems to be not quite working: I'm seeing this kernel message on boot: hw-breakpoint: debug architecture 0x4 unsupported. and then at runtime, the result of a PTRACE_GETHBPREGS call for register 0 is 0x04000106: debug architecture: 4 watchpoint size: 0 nr. watchpoints: 1 nr. breakpoints: 6 This leads me to a couple of questions: - It seems odd that the kernel says it doesn't support the debug architecture, but then reports to user space that 1 watchpoint and 6 breakpoints are supported ... GDB will never use the watchpoint, because the maximum watchpoint size is reported as zero, but GDB will attempt to use the breakpoints. Setting a breakpoint will appear to succeed, but then the breakpoint just never triggers. The kernel should IMO be more consistent in how unsupported configurations are handled ... - Why is architecture 0x4 not supported? This seems to be the variant of the v7 debug architecture with memory-mapped registers. Apparently the IGEP only supports this version ... Do you know what the Beagle-/Pandaboard and other clones do? What would it take to support this architecture variant? Given the widespread use of those boards, it would be really nice if we could support hardware debugging on them ... - Which hardware *is* supported? Can you recommend a board I should be using to verify GDB support is working? Thanks for your help in getting this working! Mit freundlichen Gruessen / Best Regards Ulrich Weigand -- Dr. Ulrich Weigand | Phone: +49-7031/16-3727 STSM, GNU compiler and toolchain for Linux on System z and Cell/B.E. IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Martin Jetter | Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen | Registergericht: Amtsgericht Stuttgart, HRB 243294 _______________________________________________ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
