From d31a580266eeb1f355df90fde8a71f480e30ad70 Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Fri, 18 May 2018 08:47:12 +0200 Subject: x86/unwind/orc: Detect the end of the stack The existing UNWIND_HINT_EMPTY annotations happen to be good indicators of where entry code calls into C code for the first time. So also use them to mark the end of the stack for the ORC unwinder. Use that information to set unwind->error if the ORC unwinder doesn't unwind all the way to the end. This will be needed for enabling HAVE_RELIABLE_STACKTRACE for the ORC unwinder so we can use it with the livepatch consistency model. Thanks to Jiri Slaby for teaching the ORCs about the unwind hints. Signed-off-by: Josh Poimboeuf Signed-off-by: Jiri Slaby Acked-by: Josh Poimboeuf Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: https://lkml.kernel.org/lkml/20180518064713.26440-5-jslaby@suse.cz Signed-off-by: Ingo Molnar --- arch/x86/entry/entry_64.S | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86/entry') diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 73a522d53b53..c6f3677e6105 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -408,6 +408,7 @@ ENTRY(ret_from_fork) 1: /* kernel thread */ + UNWIND_HINT_EMPTY movq %r12, %rdi CALL_NOSPEC %rbx /* -- cgit v1.2.3