debug_core: disable hw_breakpoints on all cores in kgdb_cpu_enter()
authorDongdong Deng <dongdong.deng@windriver.com>
Mon, 13 Sep 2010 11:58:00 +0000 (06:58 -0500)
committerJason Wessel <jason.wessel@windriver.com>
Fri, 22 Oct 2010 20:34:12 +0000 (15:34 -0500)
commitc1bb9a9c1911036549c5cdfb23f32d7d20ffdc5a
tree8d86976df36697e54ae3582d6c30b7355a942647
parent91b152aa85bbcf076e269565394c31964f940371
debug_core: disable hw_breakpoints on all cores in kgdb_cpu_enter()

The slave cpus do not have the hw breakpoints disabled upon entry to
the debug_core and as a result could cause unrecoverable recursive
faults on badly placed breakpoints, or get out of sync with the arch
specific hw breakpoint operations.

This patch addresses the problem by invoking kgdb_disable_hw_debug()
earlier in kgdb_enter_cpu for each cpu that enters the debug core.

The hw breakpoint dis/enable flow should be:

master_debug_cpu   slave_debug_cpu
         \              /
          kgdb_cpu_enter
                |
        kgdb_disable_hw_debug --> uninstall pre-enabled hw_breakpoint
                |
 do add/rm dis/enable operates to hw_breakpoints on master_debug_cpu..
                |
        correct_hw_break --> correct/install the enabled hw_breakpoint
                |
           leave_kgdb

Signed-off-by: Dongdong Deng <dongdong.deng@windriver.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
kernel/debug/debug_core.c