Messages in this thread | | | Date | Thu, 9 Feb 2017 13:14:52 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCHv3] arm: ftrace: Adds support for CONFIG_DYNAMIC_FTRACE_WITH_REGS |
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[ sending again with Masami Cc'd ]
On Thu, 9 Feb 2017 13:14:14 -0500 Steven Rostedt <rostedt@goodmis.org> wrote:
> On Thu, 9 Feb 2017 18:06:44 +0000 > Russell King - ARM Linux <linux@armlinux.org.uk> 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
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