[PATCH v2 1/5] powerpc64/ftrace: Add a field in paca to disable ftrace in unsafe code paths

[Steven Rostedt]

On Wed, 21 Mar 2018 16:13:18 +0530
"Naveen N. Rao" <naveen.n.rao at linux.vnet.ibm.com> wrote:

> We have some C code that we call into from real mode where we cannot
> take any exceptions. Though the C functions themselves are mostly safe,
> if these functions are traced, there is a possibility that we may take
> an exception. For instance, in certain conditions, the ftrace code uses
> WARN(), which uses a 'trap' to do its job.
> 
> For such scenarios, introduce a new field in paca 'ftrace_disabled',
> which is checked on ftrace entry before continuing. This field can then
> be set to a non-zero value to disable/pause ftrace, and reset to zero to
> resume ftrace.

Looks fine to me:

Acked-by: Steven Rostedt (VMware) <rostedt at goodmis.org>

-- Steve

> 
> Signed-off-by: Naveen N. Rao <naveen.n.rao at linux.vnet.ibm.com>
> ---