* amd64obsd-tdep.c (amd64obsd_sigtramp_p): Detect new signal

trampoline to be introduced in OpenBSD 5.0.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index b2bf063..296feb7 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2011-12-17  Mark Kettenis  <kettenis@gnu.org>
+
+       * amd64obsd-tdep.c (amd64obsd_sigtramp_p): Detect new signal
+       trampoline to be introduced in OpenBSD 5.0.
+
 2011-12-17  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
        Fix build regression from the PR threads/10729 fix.

diff --git a/gdb/amd64obsd-tdep.c b/gdb/amd64obsd-tdep.c
index 2ff5c8f..e66cd2b 100644 (file)
--- a/gdb/amd64obsd-tdep.c
+++ b/gdb/amd64obsd-tdep.c
@@ -88,12 +88,18 @@ amd64obsd_sigtramp_p (struct frame_info *this_frame)
 {
   CORE_ADDR pc = get_frame_pc (this_frame);
   CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1));
-  const gdb_byte sigreturn[] =
+  const gdb_byte osigreturn[] =
   {
     0x48, 0xc7, 0xc0,
     0x67, 0x00, 0x00, 0x00,    /* movq $SYS_sigreturn, %rax */
     0xcd, 0x80                 /* int $0x80 */
   };
+  const gdb_byte sigreturn[] =
+  {
+    0x48, 0xc7, 0xc0,
+    0x67, 0x00, 0x00, 0x00,    /* movq $SYS_sigreturn, %rax */
+    0x0f, 0x05                 /* syscall */
+  };
   size_t buflen = (sizeof sigreturn) + 1;
   gdb_byte *buf;
   char *name;
@@ -116,9 +122,12 @@ amd64obsd_sigtramp_p (struct frame_info *this_frame)
 
   /* Check for sigreturn(2).  Depending on how the assembler encoded
      the `movq %rsp, %rdi' instruction, the code starts at offset 6 or
-     7.  */
+     7.  OpenBSD 5.0 and later use the `syscall' instruction.  Older
+     versions use `int $0x80'.  Check for both.  */
   if (memcmp (buf, sigreturn, sizeof sigreturn)
-      && memcpy (buf + 1, sigreturn, sizeof sigreturn))
+      && memcmp (buf + 1, sigreturn, sizeof sigreturn)
+      && memcmp (buf, osigreturn, sizeof osigreturn)
+      && memcmp (buf + 1, osigreturn, sizeof osigreturn))
     return 0;
 
   return 1;