From mboxrd@z Thu Jan 1 00:00:00 1970 From: rostedt@goodmis.org (Steven Rostedt) Date: Thu, 3 Dec 2015 10:31:39 -0500 Subject: [PATCH] arm64: ftrace: stop using kstop_machine to enable/disable tracing In-Reply-To: <20151203150926.GG11337@arm.com> References: <1448697009-17211-1-git-send-email-huawei.libin@huawei.com> <20151202123654.GC4523@arm.com> <56600992.4040005@huawei.com> <20151203093821.GD7023@arm.com> <20151203100525.70cc40de@gandalf.local.home> <20151203150926.GG11337@arm.com> Message-ID: <20151203103139.35648cc2@gandalf.local.home> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, 3 Dec 2015 15:09:26 +0000 Will Deacon wrote: > Yeah, I think the comments on x86 and arm64 are out of date. They also > mention the freeing of __init sections -- is that still a concern? No we black list them, any section that we are not sure will be there when we expect it to has recordmcount.c nop out the calls to mcount and they are ignored. Remember the e1000e bug? This was the reproducer. Anyway, on my todo list is to allow init sections to be traced. To do so would mean that I need to add generic code that lets ftrace know to remove init sections at boot up. Right now (or at least the last time I checked, which was back in 2009), every arch had its own way of freeing init memory. If that has changed, or I can just place a hook where it happens (which is probably the easy part), I can allow init code to be traced too. -- Steve