From f6866b9e4a6341c50eb1d923dbf48eca2ca40140 Mon Sep 17 00:00:00 2001
From: Khem Raj <raj.khem@gmail.com>
Date: Tue, 22 Mar 2016 16:19:29 +0000
Subject: [PATCH 3/6] x86: Stub out x86_local_resume()

its purpose seems
to be unwinding across signal handler boundaries, which cannot happen
in correct programs anyway. Replacing the whole function with
something like *(volatile char *)0=0; (i.e. crash), gets a working
libunwind

Upstream-Status: Pending
Signed-off-by: Khem Raj <raj.khem@gmail.com>

---
 src/x86/Gos-linux.c | 22 +---------------------
 1 file changed, 1 insertion(+), 21 deletions(-)

diff --git a/src/x86/Gos-linux.c b/src/x86/Gos-linux.c
index fb9a5e3..c25ae0c 100644
--- a/src/x86/Gos-linux.c
+++ b/src/x86/Gos-linux.c
@@ -284,27 +284,7 @@ x86_r_uc_addr (ucontext_t *uc, int reg)
 HIDDEN int
 x86_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg)
 {
-  struct cursor *c = (struct cursor *) cursor;
-  ucontext_t *uc = c->uc;
-
-  /* Ensure c->pi is up-to-date.  On x86, it's relatively common to be
-     missing DWARF unwind info.  We don't want to fail in that case,
-     because the frame-chain still would let us do a backtrace at
-     least.  */
-  dwarf_make_proc_info (&c->dwarf);
-
-  if (unlikely (c->sigcontext_format != X86_SCF_NONE))
-    {
-      struct sigcontext *sc = (struct sigcontext *) c->sigcontext_addr;
-
-      Debug (8, "resuming at ip=%x via sigreturn(%p)\n", c->dwarf.ip, sc);
-      x86_sigreturn (sc);
-    }
-  else
-    {
-      Debug (8, "resuming at ip=%x via setcontext()\n", c->dwarf.ip);
-      setcontext (uc);
-    }
+  *(volatile char *)0=0;
   return -UNW_EINVAL;
 }
 
-- 
2.20.1