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
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| @@ -485,6 +485,9 @@ static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs) · 484 unmodified lines | ||
| 485 | 485 | int error; |
| 486 | 486 | int i, cpu; |
| 487 | 487 | int trace_on = 0; |
| 488 | + | |
| 489 | + kgdb_disable_hw_debug(ks->linux_regs); | |
| 490 | + | |
| 488 | 491 | acquirelock: |
| 489 | 492 | /* |
| 490 | 493 | * Interrupts will be restored by the 'trap return' code, except when |
| @@ -569,8 +572,6 @@ return_normal: · 78 unmodified lines | ||
| 569 | 572 | if (dbg_io_ops->pre_exception) |
| 570 | 573 | dbg_io_ops->pre_exception(); |
| 571 | 574 | |
| 572 | − kgdb_disable_hw_debug(ks->linux_regs); | |
| 573 | − | |
| 574 | 575 | /* |
| 575 | 576 | * Get the passive CPU lock which will hold all the non-primary |
| 576 | 577 | * CPU in a spin state while the debugger is active |
| @@ -661,6 +662,8 @@ kgdb_restore: · 84 unmodified lines | ||
| 661 | 662 | else |
| 662 | 663 | kgdb_sstep_pid = 0; |
| 663 | 664 | } |
| 665 | + if (arch_kgdb_ops.correct_hw_break) | |
| 666 | + arch_kgdb_ops.correct_hw_break(); | |
| 664 | 667 | if (trace_on) |
| 665 | 668 | tracing_on(); |
| 666 | 669 | /* Free kgdb_active */ |