[PATCH] x86-64: Speed up dwarf2 unwinder

This changes the dwarf2 unwinder to do a binary search for CIEs
instead of a linear work. The linker is unfortunately not
able to build a proper lookup table at link time, instead it creates
one at runtime as soon as the bootmem allocator is usable (so you'll continue
using the linear lookup for the first [hopefully] few calls).
The code should be ready to utilize a build-time created table once
a fixed linker becomes available.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>

1 files changed, 1 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index 62a1343cf327..389ff0cca9a7 100644
--- a/Makefile
+++ b/Makefile
@@ -499,6 +499,7 @@ endif
 
 ifdef CONFIG_UNWIND_INFO
 CFLAGS          += -fasynchronous-unwind-tables
+LDFLAGS_vmlinux += --eh-frame-hdr
 endif
 
 ifdef CONFIG_DEBUG_INFO