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/include/asm/module.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'arch/x86/include/asm/module.h') diff --git a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h index e3b7819caeef..9eb7c718aaf8 100644 --- a/arch/x86/include/asm/module.h +++ b/arch/x86/include/asm/module.h @@ -2,6 +2,15 @@ #define _ASM_X86_MODULE_H #include +#include + +struct mod_arch_specific { +#ifdef CONFIG_ORC_UNWINDER + unsigned int num_orcs; + int *orc_unwind_ip; + struct orc_entry *orc_unwind; +#endif +}; #ifdef CONFIG_X86_64 /* X86_64 does not define MODULE_PROC_FAMILY */ -- cgit v1.2.3