Re: [Patch 3/3] HW-BKPT: Enable/disable the breakpoints when stillregistered

From: Ananth N Mavinakayanahalli
Date: Thu Aug 27 2009 - 01:55:29 EST


On Thu, Aug 27, 2009 at 01:45:06AM +0530, K.Prasad wrote:

...

> struct hw_breakpoint {
> + /*
> + * Denotes if a breakpoint is currently enabled in physical debug
> + * registers. Not to be set directly by the end-user. Must be
> + * operated through enable_hw_breakpoint() API only.
> + */
> + unsigned int enabled;

bool?

...

> +void enable_hw_breakpoint(struct hw_breakpoint *bp, struct task_struct *tsk,
> + unsigned int enabled)
> +{
> + int i;
> + struct thread_struct *thread = &(tsk->thread);
> +
> + spin_lock_bh(&hw_breakpoint_lock);
> +
> + bp->enabled = enabled;
> + /* Enable/Disable the kernel-space breakpoint */
> + if (!tsk) {
> + if (cpumask_test_cpu(smp_processor_id(), bp->cpumask))
> + arch_update_kernel_hw_breakpoint(NULL);
> + smp_call_function_many(bp->cpumask,
> + arch_update_kernel_hw_breakpoint, NULL, 1);
> + goto out;
> + }
> +
> + /* Enable/disable the user-space breakpoint */
> + for (i = 0; i < hbp_kernel_pos; i++) {
> + if (thread->hbp[i] != bp)
> + continue;
> + arch_update_user_hw_breakpoint(i, tsk);
> + if (tsk == current)
> + arch_install_thread_hw_breakpoint(tsk);
> + break;
> + }
> +out:
> + spin_unlock_bh(&hw_breakpoint_lock);
> +}
> +EXPORT_SYMBOL_GPL(enable_hw_breakpoint);

Not sure if its cleaner to have enable_hw_breakpoint() and
disable_hw_breakpoint() rather than one overloaded call.

Ananth
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