From mboxrd@z Thu Jan 1 00:00:00 1970 From: andr2000@gmail.com (Oleksandr Andrushchenko) Date: Fri, 7 Apr 2017 20:38:03 +0300 Subject: [PATCH v1] arm64: Add support for on-demand backtrace of other CPUs In-Reply-To: References: <1489735663-2091-1-git-send-email-andr2000@gmail.com> <1489735663-2091-2-git-send-email-andr2000@gmail.com> <20170407170203.GC20645@e104818-lin.cambridge.arm.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/07/2017 08:09 PM, Daniel Thompson wrote: > On 07/04/17 18:02, Catalin Marinas wrote: >> On Fri, Mar 17, 2017 at 09:27:43AM +0200, Oleksandr Andrushchenko wrote: >>> From: Daniel Thompson >>> >>> Currently arm64 has no implementation of >>> arch_trigger_cpumask_backtrace. >>> The patch provides one using library code recently added by Russell >>> King >>> for for the majority of the implementation. Currently this is realized >>> using regular irqs but could, in the future, be implemented using >>> NMI-like mechanisms. >>> >>> Note: There is a small (and nasty) change to the generic code to ensure >>> good stack traces. The generic code currently assumes that >>> show_regs() will include a stack trace but arch/arm64 does not do >>> this so we must add extra code here. Ideas on a better approach >>> here would be very welcome (is there any appetite to change arm64 >>> show_regs() or should we just tease out the dump code into a >>> callback >> >> Please see this discussion here: >> >> http://lkml.kernel.org/r/20170323150357.GH9287 at leverpostej >> >> I'm not a ware of a follow up but if we change the arm64 show_regs() to >> dump the stack, we no longer need the generic code hunk in your patch. > > Great. That hack did always irk me! > > I'll tidy it up the next time I push out the PMR interrupt masking > patch set. > > Is there any interest in taking the patch before that. I don't mind > separating it out... I'm just not sure how useful it is. > Yes, please, could you make it as a separate patch, so it gets in the tree faster? As to if it is useful... It is. I am working on Xen hypervisor [1] and sometimes it is sooo useful to see what all the cores do. Thank you in advance, Oleksandr [1] https://www.xenproject.org/