Hi Will, Thanks for your point out very much , I see your meaning , And I do a try , But Seems it can just work when you register a Perf event with a NULL callback function, https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/tree/arch/arm/kernel/hw_breakpoint.c#n758 i don't know why it design like this? If it can always step the watchpoint, Will be suitable for my use. Thanks -----Original Message----- From: Will Deacon [mailto:will.deacon@xxxxxxx] Sent: Thursday, June 05, 2014 2:02 AM To: Wang, Yalin Cc: 'linux-mmc@xxxxxxxxxxxxxxx'; 'linux-arch-owner@xxxxxxxxxxxxxxx' Subject: Re: how to creat watchpoint in kernel for data access debug On Wed, Jun 04, 2014 at 04:05:03AM +0100, Wang, Yalin wrote: > Hi Will, > > Thanks for your proposal, > The patch google made is just like > The one I tried before , > Then the problems come : > After register the perf_event callback, In the callback function , In > google's patch , it is function crbug_345917_handler( ), It just call > panic( ) , But My callback function will do some check , Sometimes, I > want to bypass this time's breakpoint, Problems is that I don't know > how to bypass it, If I return directly in the callback function , The > breakpoint will trap again and again endless .. Take a look at enable_single_step, which uses mismatch breakpoints to try and do the step. Will -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
