On Thu, Jun 05, 2014 at 04:40:02AM +0100, Wang, Yalin wrote: > 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? That's so that ptrace users can deal with the stepping themselves, which is expected by programs such as GDB. Also, not all ARM CPUs have mismatch breakpoints (e.g. ARMv6), so software emulation is required there. 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