From ee9f8fce99640811b2b8e79d0d1dbe8bab69ba67 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Mon, 24 Jul 2017 18:36:57 -0500 Subject: x86/unwind: Add the ORC unwinder Add the new ORC unwinder which is enabled by CONFIG_ORC_UNWINDER=y. It plugs into the existing x86 unwinder framework. It relies on objtool to generate the needed .orc_unwind and .orc_unwind_ip sections. For more details on why ORC is used instead of DWARF, see Documentation/x86/orc-unwinder.txt - but the short version is that it's a simplified, fundamentally more robust debugninfo data structure, which also allows up to two orders of magnitude faster lookups than the DWARF unwinder - which matters to profiling workloads like perf. Thanks to Andy Lutomirski for the performance improvement ideas: splitting the ORC unwind table into two parallel arrays and creating a fast lookup table to search a subset of the unwind table. Signed-off-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Jiri Slaby Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/0a6cbfb40f8da99b7a45a1a8302dc6aef16ec812.1500938583.git.jpoimboe@redhat.com [ Extended the changelog. ] Signed-off-by: Ingo Molnar --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86/Kconfig') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 781521b7cf9e..7ccf26a427cb 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -157,6 +157,7 @@ config X86 select HAVE_MEMBLOCK select HAVE_MEMBLOCK_NODE_MAP select HAVE_MIXED_BREAKPOINTS_REGS + select HAVE_MOD_ARCH_SPECIFIC select HAVE_NMI select HAVE_OPROFILE select HAVE_OPTPROBES -- cgit