From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>,
linuxppc-dev@lists.ozlabs.org,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [v5, 01/10] powerpc64/ftrace: Add a field in paca to disable ftrace in unsafe code paths
Date: Wed, 9 May 2018 00:52:36 +1000 (AEST) [thread overview]
Message-ID: <40gMsd0tycz9s4Z@ozlabs.org> (raw)
In-Reply-To: <47c79b5591208f332876fc548186b5b1e3b68e52.1524121038.git.naveen.n.rao@linux.vnet.ibm.com>
On Thu, 2018-04-19 at 07:04:00 UTC, "Naveen N. Rao" 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_enabled',
> which is checked on ftrace entry before continuing. This field can then
> be set to zero to disable/pause ftrace, and set to a non-zero value to
> resume ftrace.
>
> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Series applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/ea678ac627e01daf5b4f1da24bf1d0
cheers
next prev parent reply other threads:[~2018-05-08 14:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-19 7:03 [PATCH v5 00/10] powerpc64/ftrace: Add support for ftrace_modify_call() and a few other fixes Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 01/10] powerpc64/ftrace: Add a field in paca to disable ftrace in unsafe code paths Naveen N. Rao
2018-05-08 14:52 ` Michael Ellerman [this message]
2018-04-19 7:04 ` [PATCH v5 02/10] powerpc64/ftrace: Rearrange #ifdef sections in ftrace.h Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 03/10] powerpc64/ftrace: Add helpers to hard disable ftrace Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 04/10] powerpc64/ftrace: Delay enabling ftrace on secondary cpus Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 05/10] powerpc64/ftrace: Disable ftrace during hotplug Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 06/10] powerpc64/ftrace: Disable ftrace during kvm entry/exit Naveen N. Rao
2018-04-19 15:22 ` Steven Rostedt
2018-04-20 6:31 ` Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 07/10] powerpc64/kexec: Hard disable ftrace before switching to the new kernel Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 08/10] powerpc64/module: Tighten detection of mcount call sites with -mprofile-kernel Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 09/10] powerpc64/ftrace: Use the generic version of ftrace_replace_code() Naveen N. Rao
2018-04-19 7:04 ` [PATCH v5 10/10] powerpc64/ftrace: Implement support for ftrace_regs_caller() Naveen N. Rao
2018-04-19 15:28 ` [PATCH v5 00/10] powerpc64/ftrace: Add support for ftrace_modify_call() and a few other fixes Steven Rostedt
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