Michael Ellerman wrote:
Michael Ellerman <m...@ellerman.id.au> writes:
"Naveen N. Rao" <naveen.n....@linux.vnet.ibm.com> writes:
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 disable ftrace, let's use that
before switching to a new kernel during kexec.
Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
---
arch/powerpc/kernel/machine_kexec.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/machine_kexec.c
b/arch/powerpc/kernel/machine_kexec.c
index 2694d078741d..4a1b24a9dd61 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -95,16 +95,14 @@ void arch_crash_save_vmcoreinfo(void)
*/
void machine_kexec(struct kimage *image)
{
- int save_ftrace_enabled;
-
- save_ftrace_enabled = __ftrace_enabled_save();
+ get_paca()->ftrace_disabled = 1;
This doesn't compile on 32-bit:
Failed: powerpc-next/corenet32_smp_defconfig/powerpc-5.3
(http://kisskb.ozlabs.ibm.com/kisskb/buildresult/13314085/log/)
/kisskb/src/arch/powerpc/kernel/machine_kexec.c:105:12: error: invalid type
argument of '->' (have 'int')
/kisskb/src/arch/powerpc/kernel/machine_kexec.c:98:12: error: invalid type
argument of '->' (have 'int')
/kisskb/src/arch/powerpc/kernel/machine_kexec.c:98:2: error: implicit
declaration of function 'get_paca' [-Werror=implicit-function-declaration]
Hmm... pmac32_defconfig built fine for me, so I thought we are ok there.
A wrapper is probably best that does nothing on 32-bit.
Actually it should probably do __ftrace_enabled_save() etc. on 32-bit,
like the existing code does.
Agree. In hindsight, I'm not updating ftrace_32.S, so I think I will
gate this with CONFIG_PPC64.
Thanks,
Naveen
