Re: [PATCH 1/3][RFC] ftrace/ppc: Have PPC skip updating withstop_machine()

From: Michael Ellerman
Date: Fri Jun 08 2012 - 00:13:56 EST


On Thu, 2012-04-26 at 14:31 -0400, Steven Rostedt wrote:
> plain text document attachment
> (0001-ftrace-ppc-Have-PPC-skip-updating-with-stop_machine.patch)
> From: Steven Rostedt <srostedt@xxxxxxxxxx>
>
> PPC does not have the synchronization issues that x86 has with
> modifying code on one CPU while another CPU is executing it.
> The other CPU will either see the old or new code without any
> issues, unlike x86 which may issue a GPF.
>
> Instead of calling the heavy stop_machine, just update the code.

This looks nice, but it's giving me this:

arch/powerpc/kernel/ftrace.c:497:13: error: static declaration of 'ftrace_replace_code' follows non-static declaration
include/linux/ftrace.h:317:13: note: previous declaration of 'ftrace_replace_code' was here

I think the fix is just to make our ftrace_replace_code() non-static?

cheers


> +static void ftrace_replace_code(int enable)
> +{
> + struct ftrace_rec_iter *iter;
> + struct dyn_ftrace *rec;
> + int ret;
> +
> + for (iter = ftrace_rec_iter_start(); iter;
> + iter = ftrace_rec_iter_next(iter)) {
> + rec = ftrace_rec_iter_record(iter);
> + ret = __ftrace_replace_code(rec, enable);
> + if (ret) {
> + ftrace_bug(ret, rec->ip);
> + return;
> + }
> + }
> +}
> +


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