From mboxrd@z Thu Jan 1 00:00:00 1970 From: rostedt@goodmis.org (Steven Rostedt) Date: Thu, 9 Feb 2017 13:14:52 -0500 Subject: [PATCHv3] arm: ftrace: Adds support for CONFIG_DYNAMIC_FTRACE_WITH_REGS In-Reply-To: <20170209131414.098c848c@gandalf.local.home> References: <1486508275-18449-1-git-send-email-abelvesa@linux.com> <20170209162956.GH27312@n2100.armlinux.org.uk> <20170209121322.5229e6cf@gandalf.local.home> <20170209180644.GJ27312@n2100.armlinux.org.uk> <20170209131414.098c848c@gandalf.local.home> Message-ID: <20170209131452.472aa882@gandalf.local.home> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org [ sending again with Masami Cc'd ] On Thu, 9 Feb 2017 13:14:14 -0500 Steven Rostedt wrote: > On Thu, 9 Feb 2017 18:06:44 +0000 > Russell King - ARM Linux wrote: > > > On Thu, Feb 09, 2017 at 12:13:22PM -0500, Steven Rostedt wrote: > > > Then came along live kernel patching, which I believe this series is > > > trying to support. What is needed by pt_regs is a way to "hijack" the > > > function being called to instead call the patched function. That is, > > > ftrace is not being used for tracing, but in reality, being used to > > > modify the running kernel. It is being used to change what function > > > gets called. ftrace is just a hook for that mechanism. > > > > So, would I be correct to assume that the only parts of pt_regs that > > would be touched are those which contain arguments to the function, > > and the register which would contain the return value? > > > > For live kernel patching, perhaps. > > But for kprobes, I think they can touch anything. Matters what the > creater of the kprobe wanted to do. > > -- Steve