From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
Steven Rostedt <rostedt@goodmis.org>
Cc: linuxppc-dev@lists.ozlabs.org, Paul Mackerras <paulus@ozlabs.org>,
Nicholas Piggin <npiggin@gmail.com>,
Anton Blanchard <anton@samba.org>,
sathnaga@linux.vnet.ibm.com
Subject: [PATCH v4 07/10] powerpc64/kexec: Hard disable ftrace before switching to the new kernel
Date: Wed, 4 Apr 2018 01:42:22 +0530 [thread overview]
Message-ID: <d7b2a1c5f6a57822b604363615c885d294305f63.1522784883.git.naveen.n.rao@linux.vnet.ibm.com> (raw)
In-Reply-To: <cover.1522784883.git.naveen.n.rao@linux.vnet.ibm.com>
In-Reply-To: <cover.1522784883.git.naveen.n.rao@linux.vnet.ibm.com>
If function_graph tracer is enabled during kexec, we see the below
exception in the simulator:
root@(none):/# kexec -e
kvm: exiting hardware virtualization
kexec_core: Starting new kernel
[ 19.262020070,5] OPAL: Switch to big-endian OS
kexec: Starting switchover sequence.
Interrupt to 0xC000000000004380 from 0xC000000000004380
** Execution stopped: Continuous Interrupt, Instruction caused exception, **
Now that we have a more effective way to completely disable ftrace on
ppc64, let's also use that before switching to a new kernel during
kexec.
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
arch/powerpc/kernel/machine_kexec.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index 2694d078741d..936c7e2d421e 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -98,12 +98,14 @@ void machine_kexec(struct kimage *image)
int save_ftrace_enabled;
save_ftrace_enabled = __ftrace_enabled_save();
+ this_cpu_disable_ftrace();
if (ppc_md.machine_kexec)
ppc_md.machine_kexec(image);
else
default_machine_kexec(image);
+ this_cpu_enable_ftrace();
__ftrace_enabled_restore(save_ftrace_enabled);
/* Fall back to normal restart if we're still alive. */
--
2.16.2
next prev parent reply other threads:[~2018-04-03 20:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-03 20:12 [PATCH v4 00/10] powerpc64/ftrace: Add support for ftrace_modify_call() and a few other fixes Naveen N. Rao
2018-04-03 20:12 ` [PATCH v4 01/10] powerpc64/ftrace: Add a field in paca to disable ftrace in unsafe code paths Naveen N. Rao
2018-04-03 20:12 ` [PATCH v4 02/10] powerpc64/ftrace: Disable ftrace during kvm guest entry/exit Naveen N. Rao
2018-04-03 20:12 ` [PATCH v4 03/10] powerpc64/ftrace: Rearrange #ifdef sections in ftrace.h Naveen N. Rao
2018-04-03 20:12 ` [PATCH v4 04/10] powerpc64/ftrace: Add helpers to hard disable ftrace Naveen N. Rao
2018-04-03 20:12 ` [PATCH v4 05/10] powerpc64/ftrace: Delay enabling ftrace on secondary cpus Naveen N. Rao
2018-04-03 20:12 ` [PATCH v4 06/10] powerpc64/ftrace: Disable ftrace during hotplug Naveen N. Rao
2018-04-03 20:12 ` Naveen N. Rao [this message]
2018-04-03 20:12 ` [PATCH v4 08/10] powerpc64/module: Tighten detection of mcount call sites with -mprofile-kernel Naveen N. Rao
2018-04-03 20:12 ` [PATCH v4 09/10] powerpc64/ftrace: Use the generic version of ftrace_replace_code() Naveen N. Rao
2018-04-03 20:12 ` [PATCH v4 10/10] powerpc64/ftrace: Implement support for ftrace_regs_caller() Naveen N. Rao
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