[RFC 1/1] orc: mark it as reliable

Jiri Slaby
2017-10-04T09:23:18Z

We need a reliable stack unwinder for kernel live patching, but we do
not want to enable frame pointers for performance reasons. So let ORC be
a reliable stack unwinder on x86 as it performs nicely wrt reliability
of traces.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
---

I am sending this as an RFC. Do you still consider ORC to be not-enough
reliable?

arch/x86/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 063f1e0d51aa..7403267407fc 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -172,7 +172,7 @@ config X86
select HAVE_PERF_USER_STACK_DUMP
select HAVE_RCU_TABLE_FREE
select HAVE_REGS_AND_STACK_ACCESS_API
- select HAVE_RELIABLE_STACKTRACE if X86_64 && FRAME_POINTER_UNWINDER && STACK_VALIDATION
+ select HAVE_RELIABLE_STACKTRACE if X86_64 && (FRAME_POINTER_UNWINDER || ORC_UNWINDER) && STACK_VALIDATION
select HAVE_STACK_VALIDATION if X86_64
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UNSTABLE_SCHED_CLOCK
--
2.14.2