From c64723835c0c855fde5bec3d7528db64fe539015 Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kostik@pooma.home>
Date: Sun, 7 Mar 2010 21:53:01 +0200
Subject: [PATCH] Support walk over freebsd sigframes

---
 include/tdep-x86_64/libunwind_i.h |  3 ++-
 src/x86/offsets.h                 |  3 +++
 src/x86_64/Gis_signal_frame.c     | 13 +++++--------
 src/x86_64/Gregs.c                |  4 ++++
 src/x86_64/Gstep.c                | 14 +++++++++++++-
 5 files changed, 27 insertions(+), 10 deletions(-)

diff --git a/include/tdep-x86_64/libunwind_i.h b/include/tdep-x86_64/libunwind_i.h
index a949a4cb..974d610e 100644
--- a/include/tdep-x86_64/libunwind_i.h
+++ b/include/tdep-x86_64/libunwind_i.h
@@ -62,7 +62,8 @@ struct cursor
     enum
       {
 	X86_64_SCF_NONE,		/* no signal frame encountered */
-	X86_64_SCF_LINUX_RT_SIGFRAME	/* POSIX ucontext_t */
+	X86_64_SCF_LINUX_RT_SIGFRAME,	/* Linux ucontext_t */
+	X86_64_SCF_FREEBSD_SIGFRAME,	/* FreeBSD ucontext_t */
       }
     sigcontext_format;
     unw_word_t sigcontext_addr;
diff --git a/src/x86/offsets.h b/src/x86/offsets.h
index 94307c12..63a28729 100644
--- a/src/x86/offsets.h
+++ b/src/x86/offsets.h
@@ -82,3 +82,6 @@
 #define LINUX_FPSTATE_XMM5_OFF		0x160
 #define LINUX_FPSTATE_XMM6_OFF		0x170
 #define LINUX_FPSTATE_XMM7_OFF		0x180
+
+/* FreeBSD specific definitions */
+#define FREEBSD_UC_MCONTEXT_OFF		0x10
diff --git a/src/x86_64/Gis_signal_frame.c b/src/x86_64/Gis_signal_frame.c
index 263ad87a..ce81699f 100644
--- a/src/x86_64/Gis_signal_frame.c
+++ b/src/x86_64/Gis_signal_frame.c
@@ -97,17 +97,14 @@ eb fd			jmp	0b
       || (ret = (*a->access_mem) (as, ip + 8, &w1, 0, arg)) < 0
       || (ret = (*a->access_mem) (as, ip + 16, &w2, 0, arg)) < 0)
     return 0;
-#if 0
-  fprintf(stderr, "is_signal_frame: ip %lx w0 %lx w1 %lx w2 %lx\n",
-	  ip, w0, w1, w2);
-#endif
   w2 &= 0xffffff;
-  return (w0 == 0x48006a10247c8d48 &&
+  ret = w0 == 0x48006a10247c8d48 &&
 	  w1 == 0x050f000001a1c0c7 &&
-	  w2 == 0x0000000000fdebf4);
+	  w2 == 0x0000000000fdebf4;
+  return ret;
 }
 
-#else /* __linux__ */
+#else /* !__linux__ && !__FreeBSD__ */
 
 PROTECTED int
 unw_is_signal_frame (unw_cursor_t *cursor)
@@ -115,4 +112,4 @@ unw_is_signal_frame (unw_cursor_t *cursor)
   printf ("%s: implement me\n", __FUNCTION__);
   return -UNW_ENOINFO;
 }
-#endif /* __linux__ */
+#endif
diff --git a/src/x86_64/Gregs.c b/src/x86_64/Gregs.c
index ddf7b7e3..5dd7b0b6 100644
--- a/src/x86_64/Gregs.c
+++ b/src/x86_64/Gregs.c
@@ -41,6 +41,10 @@ linux_scratch_loc (struct cursor *c, unw_regnum_t reg)
     case X86_64_SCF_LINUX_RT_SIGFRAME:
       addr += LINUX_UC_MCONTEXT_OFF;
       break;
+
+    case X86_64_SCF_FREEBSD_SIGFRAME:
+      addr += FREEBSD_UC_MCONTEXT_OFF;
+      break;
     }
 
   return DWARF_REG_LOC (&c->dwarf, reg);
diff --git a/src/x86_64/Gstep.c b/src/x86_64/Gstep.c
index 2da1c25d..5a1654e1 100644
--- a/src/x86_64/Gstep.c
+++ b/src/x86_64/Gstep.c
@@ -28,6 +28,12 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 #include "unwind_i.h"
 #include "ucontext_i.h"
 #include <signal.h>
+#include <stddef.h>
+
+#if defined __FreeBSD__
+#include <sys/ucontext.h>
+#include <machine/sigframe.h>
+#endif
 
 PROTECTED int
 unw_step (unw_cursor_t *cursor)
@@ -79,11 +85,17 @@ unw_step (unw_cursor_t *cursor)
 
       if (unw_is_signal_frame (cursor))
 	{
-	  unw_word_t ucontext = c->dwarf.cfa;
+	  unw_word_t ucontext;
 
 	  Debug(1, "signal frame, skip over trampoline\n");
 
+#if defined __linux__
+	  ucontext = c->dwarf.cfa;
 	  c->sigcontext_format = X86_64_SCF_LINUX_RT_SIGFRAME;
+#elif defined __FreeBSD__
+	  ucontext = c->dwarf.cfa + offsetof(struct sigframe, sf_uc);
+	  c->sigcontext_format = X86_64_SCF_FREEBSD_SIGFRAME;
+#endif
 	  c->sigcontext_addr = c->dwarf.cfa;
 
 	  rsp_loc = DWARF_LOC (ucontext + UC_MCONTEXT_GREGS_RSP, 0);